text: /*
   * VIM - Vi IMproved	by Bram Moolenaar
   *
   * Do ":help uganda"  in Vim to read copying and usage conditions.
   * Do ":help credits" in Vim to see a list of people who contributed.
   * See README.txt for an overview of the Vim source code.
   */
  
  /*
   * ops.c: implementation of various operators: op_shift, op_delete, op_tilde,
   *	  op_change, op_yank, do_put, do_join
   */
  
  #include <assert.h>
  #include <inttypes.h>
  #include <stdbool.h>
  #include <string.h>
  
  #include "nvim/vim.h"
  #include "nvim/ascii.h"
  #include "nvim/ops.h"
  #include "nvim/buffer.h"
  #include "nvim/charset.h"
  #include "nvim/cursor.h"
  #include "nvim/edit.h"
  #include "nvim/eval.h"
  #include "nvim/ex_cmds.h"
  #include "nvim/ex_cmds2.h"
  #include "nvim/ex_getln.h"
  #include "nvim/fold.h"
  #include "nvim/getchar.h"
  #include "nvim/indent.h"
  #include "nvim/log.h"
  #include "nvim/mark.h"
  #include "nvim/mbyte.h"
  #include "nvim/memline.h"
  #include "nvim/memory.h"
  #include "nvim/message.h"
  #include "nvim/misc1.h"
  #include "nvim/misc2.h"
  #include "nvim/move.h"
  #include "nvim/normal.h"
  #include "nvim/option.h"
  #include "nvim/path.h"
  #include "nvim/screen.h"
  #include "nvim/search.h"
  #include "nvim/strings.h"
  #include "nvim/term.h"
  #include "nvim/undo.h"
  #include "nvim/window.h"
  #include "nvim/os/input.h"
  
  /*
   * Registers:
   *      0 = unnamed register, for normal yanks and puts
   *   1..9 = registers '1' to '9', for deletes
   * 10..35 = registers 'a' to 'z'
   *     36 = delete register '-'
   */
  #define NUM_REGISTERS 38
  #define DELETION_REGISTER 36
  #define CLIP_REGISTER 37
  
  #define CB_UNNAMEDMASK (CB_UNNAMED | CB_UNNAMEDPLUS)
  #define CB_LATEST (-1)
  /*
   * Each yank register is an array of pointers to lines.
   */
  static struct yankreg {
    char_u      **y_array;        /* pointer to array of line pointers */
    linenr_T y_size;              /* number of lines in y_array */
    char_u y_type;                /* MLINE, MCHAR or MBLOCK */
    colnr_T y_width;              /* only set if y_type == MBLOCK */
  } y_regs[NUM_REGISTERS];
  
  static struct yankreg   *y_current;         /* ptr to current yankreg */
  static int y_append;                        /* TRUE when appending */
  static struct yankreg   *y_previous = NULL; /* ptr to last written yankreg */
  
  static bool clipboard_didwarn_unnamed = false;
  /*
   * structure used by block_prep, op_delete and op_yank for blockwise operators
   * also op_change, op_shift, op_insert, op_replace - AKelly
   */
  struct block_def {
    int startspaces;              /* 'extra' cols before first char */
    int endspaces;                /* 'extra' cols after last char */
    int textlen;                  /* chars in block */
    char_u      *textstart;       /* pointer to 1st char (partially) in block */
    colnr_T textcol;              /* index of chars (partially) in block */
    colnr_T start_vcol;           /* start col of 1st char wholly inside block */
    colnr_T end_vcol;             /* start col of 1st char wholly after block */
    int is_short;                 /* TRUE if line is too short to fit in block */
    int is_MAX;                   /* TRUE if curswant==MAXCOL when starting */
    int is_oneChar;               /* TRUE if block within one character */
    int pre_whitesp;              /* screen cols of ws before block */
    int pre_whitesp_c;            /* chars of ws before block */
    colnr_T end_char_vcols;       /* number of vcols of post-block char */
    colnr_T start_char_vcols;       /* number of vcols of pre-block char */
  };
  
  #ifdef INCLUDE_GENERATED_DECLARATIONS
  # include "ops.c.generated.h"
  #endif
  
  /*
   * The names of operators.
   * IMPORTANT: Index must correspond with defines in vim.h!!!
   * The third field indicates whether the operator always works on lines.
   */
  static char opchars[][3] =
  {
    {NUL, NUL, FALSE},    /* OP_NOP */
    {'d', NUL, FALSE},    /* OP_DELETE */
    {'y', NUL, FALSE},    /* OP_YANK */
    {'c', NUL, FALSE},    /* OP_CHANGE */
    {'<', NUL, TRUE},     /* OP_LSHIFT */
    {'>', NUL, TRUE},     /* OP_RSHIFT */
    {'!', NUL, TRUE},     /* OP_FILTER */
    {'g', '~', FALSE},    /* OP_TILDE */
    {'=', NUL, TRUE},     /* OP_INDENT */
    {'g', 'q', TRUE},     /* OP_FORMAT */
    {':', NUL, TRUE},     /* OP_COLON */
    {'g', 'U', FALSE},    /* OP_UPPER */
    {'g', 'u', FALSE},    /* OP_LOWER */
    {'J', NUL, TRUE},     /* DO_JOIN */
    {'g', 'J', TRUE},     /* DO_JOIN_NS */
    {'g', '?', FALSE},    /* OP_ROT13 */
    {'r', NUL, FALSE},    /* OP_REPLACE */
    {'I', NUL, FALSE},    /* OP_INSERT */
    {'A', NUL, FALSE},    /* OP_APPEND */
    {'z', 'f', TRUE},     /* OP_FOLD */
    {'z', 'o', TRUE},     /* OP_FOLDOPEN */
    {'z', 'O', TRUE},     /* OP_FOLDOPENREC */
    {'z', 'c', TRUE},     /* OP_FOLDCLOSE */
    {'z', 'C', TRUE},     /* OP_FOLDCLOSEREC */
    {'z', 'd', TRUE},     /* OP_FOLDDEL */
    {'z', 'D', TRUE},     /* OP_FOLDDELREC */
    {'g', 'w', TRUE},     /* OP_FORMAT2 */
    {'g', '@', FALSE},    /* OP_FUNCTION */
  };
  
  /*
   * Translate a command name into an operator type.
   * Must only be called with a valid operator name!
   */
  int get_op_type(int char1, int char2)
  {
    int i;
  
    if (char1 == 'r')             /* ignore second character */
      return OP_REPLACE;
    if (char1 == '~')             /* when tilde is an operator */
      return OP_TILDE;
    for (i = 0;; ++i)
      if (opchars[i][0] == char1 && opchars[i][1] == char2)
        break;
    return i;
  }
  
  /*
   * Return TRUE if operator "op" always works on whole lines.
   */
  int op_on_lines(int op)
  {
    return opchars[op][2];
  }
  
  /*
   * Get first operator command character.
   * Returns 'g' or 'z' if there is another command character.
   */
  int get_op_char(int optype)
  {
    return opchars[optype][0];
  }
  
  /*
   * Get second operator command character.
   */
  int get_extra_op_char(int optype)
  {
    return opchars[optype][1];
  }
  
  /*
   * op_shift - handle a shift operation
   */
  void op_shift(oparg_T *oap, int curs_top, int amount)
  {
    long i;
    int first_char;
    char_u          *s;
    int block_col = 0;
  
    if (u_save((linenr_T)(oap->start.lnum - 1),
            (linenr_T)(oap->end.lnum + 1)) == FAIL)
      return;
  
    if (oap->block_mode)
      block_col = curwin->w_cursor.col;
  
    for (i = oap->line_count; --i >= 0; ) {
      first_char = *get_cursor_line_ptr();
      if (first_char == NUL)                              /* empty line */
        curwin->w_cursor.col = 0;
      else if (oap->block_mode)
        shift_block(oap, amount);
      else
      /* Move the line right if it doesn't start with '#', 'smartindent'
       * isn't set or 'cindent' isn't set or '#' isn't in 'cino'. */
      if (first_char != '#' || !preprocs_left()) {
        shift_line(oap->op_type == OP_LSHIFT, p_sr, amount, FALSE);
      }
      ++curwin->w_cursor.lnum;
    }
  
    changed_lines(oap->start.lnum, 0, oap->end.lnum + 1, 0L);
    /* The cursor line is not in a closed fold */
    foldOpenCursor();
  
    if (oap->block_mode) {
      curwin->w_cursor.lnum = oap->start.lnum;
      curwin->w_cursor.col = block_col;
    } else if (curs_top) { /* put cursor on first line, for ">>" */
      curwin->w_cursor.lnum = oap->start.lnum;
      beginline(BL_SOL | BL_FIX);       /* shift_line() may have set cursor.col */
    } else
      --curwin->w_cursor.lnum;            /* put cursor on last line, for ":>" */
  
    if (oap->line_count > p_report) {
      if (oap->op_type == OP_RSHIFT)
        s = (char_u *)">";
      else
        s = (char_u *)"<";
      if (oap->line_count == 1) {
        if (amount == 1)
          sprintf((char *)IObuff, _("1 line %sed 1 time"), s);
        else
          sprintf((char *)IObuff, _("1 line %sed %d times"), s, amount);
      } else {
        if (amount == 1)
          sprintf((char *)IObuff, _("%" PRId64 " lines %sed 1 time"),
              (int64_t)oap->line_count, s);
        else
          sprintf((char *)IObuff, _("%" PRId64 " lines %sed %d times"),
              (int64_t)oap->line_count, s, amount);
      }
      msg(IObuff);
    }
  
    /*
     * Set "'[" and "']" marks.
     */
    curbuf->b_op_start = oap->start;
    curbuf->b_op_end.lnum = oap->end.lnum;
    curbuf->b_op_end.col = (colnr_T)STRLEN(ml_get(oap->end.lnum));
    if (curbuf->b_op_end.col > 0)
      --curbuf->b_op_end.col;
  }
  
  /*
   * shift the current line one shiftwidth left (if left != 0) or right
   * leaves cursor on first blank in the line
   */
  void 
  shift_line (
      int left,
      int round,
      int amount,
      int call_changed_bytes         /* call changed_bytes() */
  )
  {
    int count;
    int i, j;
    int p_sw = (int)get_sw_value(curbuf);
  
    count = get_indent();         /* get current indent */
  
    if (round) {                  /* round off indent */
      i = count / p_sw;           /* number of p_sw rounded down */
      j = count % p_sw;           /* extra spaces */
      if (j && left)              /* first remove extra spaces */
        --amount;
      if (left) {
        i -= amount;
        if (i < 0)
          i = 0;
      } else
        i += amount;
      count = i * p_sw;
    } else {            /* original vi indent */
      if (left) {
        count -= p_sw * amount;
        if (count < 0)
          count = 0;
      } else
        count += p_sw * amount;
    }
  
    /* Set new indent */
    if (State & VREPLACE_FLAG)
      change_indent(INDENT_SET, count, FALSE, NUL, call_changed_bytes);
    else
      (void)set_indent(count, call_changed_bytes ? SIN_CHANGED : 0);
  }
  
  /*
   * Shift one line of the current block one shiftwidth right or left.
   * Leaves cursor on first character in block.
   */
  static void shift_block(oparg_T *oap, int amount)
  {
    int left = (oap->op_type == OP_LSHIFT);
    int oldstate = State;
    int total;
    char_u              *newp, *oldp;
    int oldcol = curwin->w_cursor.col;
    int p_sw = (int)get_sw_value(curbuf);
    int p_ts = (int)curbuf->b_p_ts;
    struct block_def bd;
    int incr;
    colnr_T ws_vcol;
    int i = 0, j = 0;
    int len;
    int old_p_ri = p_ri;
  
    p_ri = 0;                     /* don't want revins in indent */
  
    State = INSERT;               /* don't want REPLACE for State */
    block_prep(oap, &bd, curwin->w_cursor.lnum, TRUE);
    if (bd.is_short)
      return;
  
    /* total is number of screen columns to be inserted/removed */
    total = amount * p_sw;
    oldp = get_cursor_line_ptr();
  
    if (!left) {
      /*
       *  1. Get start vcol
       *  2. Total ws vcols
       *  3. Divvy into TABs & spp
       *  4. Construct new string
       */
      total += bd.pre_whitesp;     /* all virtual WS up to & incl a split TAB */
      ws_vcol = bd.start_vcol - bd.pre_whitesp;
      if (bd.startspaces) {
        if (has_mbyte)
          bd.textstart += (*mb_ptr2len)(bd.textstart);
        else
          ++bd.textstart;
      }
      for (; vim_iswhite(*bd.textstart); ) {
        // TODO: is passing bd.textstart for start of the line OK?
        incr = lbr_chartabsize_adv(bd.textstart, &bd.textstart, (colnr_T)(bd.start_vcol));
        total += incr;
        bd.start_vcol += incr;
      }
      /* OK, now total=all the VWS reqd, and textstart points at the 1st
       * non-ws char in the block. */
      if (!curbuf->b_p_et)
        i = ((ws_vcol % p_ts) + total) / p_ts;       /* number of tabs */
      if (i)
        j = ((ws_vcol % p_ts) + total) % p_ts;       /* number of spp */
      else
        j = total;
      /* if we're splitting a TAB, allow for it */
      bd.textcol -= bd.pre_whitesp_c - (bd.startspaces != 0);
      len = (int)STRLEN(bd.textstart) + 1;
      newp = (char_u *) xmalloc((size_t)(bd.textcol + i + j + len));
      memset(newp, NUL, (size_t)(bd.textcol + i + j + len));
      memmove(newp, oldp, (size_t)bd.textcol);
      memset(newp + bd.textcol, TAB, (size_t)i);
      memset(newp + bd.textcol + i, ' ', (size_t)j);
      /* the end */
      memmove(newp + bd.textcol + i + j, bd.textstart, (size_t)len);
    } else { /* left */
      colnr_T destination_col;            /* column to which text in block will
                                             be shifted */
      char_u      *verbatim_copy_end;     /* end of the part of the line which is
                                             copied verbatim */
      colnr_T verbatim_copy_width;        /* the (displayed) width of this part
                                             of line */
      unsigned fill;                      /* nr of spaces that replace a TAB */
      unsigned new_line_len;              /* the length of the line after the
                                             block shift */
      size_t block_space_width;
      size_t shift_amount;
      char_u      *non_white = bd.textstart;
      colnr_T non_white_col;
  
      /*
       * Firstly, let's find the first non-whitespace character that is
       * displayed after the block's start column and the character's column
       * number. Also, let's calculate the width of all the whitespace
       * characters that are displayed in the block and precede the searched
       * non-whitespace character.
       */
  
      /* If "bd.startspaces" is set, "bd.textstart" points to the character,
       * the part of which is displayed at the block's beginning. Let's start
       * searching from the next character. */
      if (bd.startspaces)
        mb_ptr_adv(non_white);
  
      /* The character's column is in "bd.start_vcol".  */
      non_white_col = bd.start_vcol;
  
      while (vim_iswhite(*non_white)) {
        incr = lbr_chartabsize_adv(bd.textstart, &non_white, non_white_col);
        non_white_col += incr;
      }
  
      block_space_width = non_white_col - oap->start_vcol;
      /* We will shift by "total" or "block_space_width", whichever is less.
       */
      shift_amount = (block_space_width < (size_t)total
                      ? block_space_width : (size_t)total);
  
      /* The column to which we will shift the text.  */
      destination_col = (colnr_T)(non_white_col - shift_amount);
  
      /* Now let's find out how much of the beginning of the line we can
       * reuse without modification.  */
      verbatim_copy_end = bd.textstart;
      verbatim_copy_width = bd.start_vcol;
  
      /* If "bd.startspaces" is set, "bd.textstart" points to the character
       * preceding the block. We have to subtract its width to obtain its
       * column number.  */
      if (bd.startspaces)
        verbatim_copy_width -= bd.start_char_vcols;
      while (verbatim_copy_width < destination_col) {
        char_u *line = verbatim_copy_end;
  
        // TODO: is passing verbatim_copy_end for start of the line OK?
        incr = lbr_chartabsize(line, verbatim_copy_end, verbatim_copy_width);
        if (verbatim_copy_width + incr > destination_col)
          break;
        verbatim_copy_width += incr;
        mb_ptr_adv(verbatim_copy_end);
      }
  
      /* If "destination_col" is different from the width of the initial
      * part of the line that will be copied, it means we encountered a tab
      * character, which we will have to partly replace with spaces.  */
      fill = destination_col - verbatim_copy_width;
  
      /* The replacement line will consist of:
       * - the beginning of the original line up to "verbatim_copy_end",
       * - "fill" number of spaces,
       * - the rest of the line, pointed to by non_white.  */
      new_line_len = (unsigned)(verbatim_copy_end - oldp)
                     + fill
                     + (unsigned)STRLEN(non_white) + 1;
  
      newp = (char_u *) xmalloc((size_t)(new_line_len));
      memmove(newp, oldp, (size_t)(verbatim_copy_end - oldp));
      memset(newp + (verbatim_copy_end - oldp), ' ', (size_t)fill);
      STRMOVE(newp + (verbatim_copy_end - oldp) + fill, non_white);
    }
    /* replace the line */
    ml_replace(curwin->w_cursor.lnum, newp, FALSE);
    changed_bytes(curwin->w_cursor.lnum, (colnr_T)bd.textcol);
    State = oldstate;
    curwin->w_cursor.col = oldcol;
    p_ri = old_p_ri;
  }
  
  /*
   * Insert string "s" (b_insert ? before : after) block :AKelly
   * Caller must prepare for undo.
   */
  static void block_insert(oparg_T *oap, char_u *s, int b_insert, struct block_def *bdp)
  {
    int p_ts;
    int count = 0;                /* extra spaces to replace a cut TAB */
    int spaces = 0;               /* non-zero if cutting a TAB */
    colnr_T offset;               /* pointer along new line */
    unsigned s_len;               /* STRLEN(s) */
    char_u      *newp, *oldp;     /* new, old lines */
    linenr_T lnum;                /* loop var */
    int oldstate = State;
  
    State = INSERT;               /* don't want REPLACE for State */
    s_len = (unsigned)STRLEN(s);
  
    for (lnum = oap->start.lnum + 1; lnum <= oap->end.lnum; lnum++) {
      block_prep(oap, bdp, lnum, TRUE);
      if (bdp->is_short && b_insert)
        continue;         /* OP_INSERT, line ends before block start */
  
      oldp = ml_get(lnum);
  
      if (b_insert) {
        p_ts = bdp->start_char_vcols;
        spaces = bdp->startspaces;
        if (spaces != 0)
          count = p_ts - 1;         /* we're cutting a TAB */
        offset = bdp->textcol;
      } else { /* append */
        p_ts = bdp->end_char_vcols;
        if (!bdp->is_short) {     /* spaces = padding after block */
          spaces = (bdp->endspaces ? p_ts - bdp->endspaces : 0);
          if (spaces != 0)
            count = p_ts - 1;           /* we're cutting a TAB */
          offset = bdp->textcol + bdp->textlen - (spaces != 0);
        } else { /* spaces = padding to block edge */
                   /* if $ used, just append to EOL (ie spaces==0) */
          if (!bdp->is_MAX)
            spaces = (oap->end_vcol - bdp->end_vcol) + 1;
          count = spaces;
          offset = bdp->textcol + bdp->textlen;
        }
      }
  
      if (has_mbyte && spaces > 0) {
        int off;
  
        // Avoid starting halfway through a multi-byte character.
        if (b_insert) {
          off = (*mb_head_off)(oldp, oldp + offset + spaces);
        } else {
          off = (*mb_off_next)(oldp, oldp + offset);
          offset += off;
        }
        spaces -= off;
        count -= off;
      }
  
      newp = (char_u *) xmalloc((size_t)(STRLEN(oldp) + s_len + count + 1));
  
      /* copy up to shifted part */
      memmove(newp, oldp, (size_t)(offset));
      oldp += offset;
  
      /* insert pre-padding */
      memset(newp + offset, ' ', (size_t)spaces);
  
      /* copy the new text */
      memmove(newp + offset + spaces, s, (size_t)s_len);
      offset += s_len;
  
      if (spaces && !bdp->is_short) {
        /* insert post-padding */
        memset(newp + offset + spaces, ' ', (size_t)(p_ts - spaces));
        /* We're splitting a TAB, don't copy it. */
        oldp++;
        /* We allowed for that TAB, remember this now */
        count++;
      }
  
      if (spaces > 0)
        offset += count;
      STRMOVE(newp + offset, oldp);
  
      ml_replace(lnum, newp, FALSE);
  
      if (lnum == oap->end.lnum) {
        /* Set "']" mark to the end of the block instead of the end of
         * the insert in the first line.  */
        curbuf->b_op_end.lnum = oap->end.lnum;
        curbuf->b_op_end.col = offset;
      }
    }   /* for all lnum */
  
    changed_lines(oap->start.lnum + 1, 0, oap->end.lnum + 1, 0L);
  
    State = oldstate;
  }
  
  /*
   * op_reindent - handle reindenting a block of lines.
   */
  void op_reindent(oparg_T *oap, Indenter how)
  {
    long i;
    char_u      *l;
    int count;
    linenr_T first_changed = 0;
    linenr_T last_changed = 0;
    linenr_T start_lnum = curwin->w_cursor.lnum;
  
    /* Don't even try when 'modifiable' is off. */
    if (!curbuf->b_p_ma) {
      EMSG(_(e_modifiable));
      return;
    }
  
    for (i = oap->line_count; --i >= 0 && !got_int; ) {
      /* it's a slow thing to do, so give feedback so there's no worry that
       * the computer's just hung. */
  
      if (i > 1
          && (i % 50 == 0 || i == oap->line_count - 1)
          && oap->line_count > p_report)
        smsg((char_u *)_("%" PRId64 " lines to indent... "), (int64_t)i);
  
      /*
       * Be vi-compatible: For lisp indenting the first line is not
       * indented, unless there is only one line.
       */
      if (i != oap->line_count - 1 || oap->line_count == 1
          || how != get_lisp_indent) {
        l = skipwhite(get_cursor_line_ptr());
        if (*l == NUL)                        /* empty or blank line */
          count = 0;
        else
          count = how();                      /* get the indent for this line */
  
        if (set_indent(count, SIN_UNDO)) {
          /* did change the indent, call changed_lines() later */
          if (first_changed == 0)
            first_changed = curwin->w_cursor.lnum;
          last_changed = curwin->w_cursor.lnum;
        }
      }
      ++curwin->w_cursor.lnum;
      curwin->w_cursor.col = 0;      /* make sure it's valid */
    }
  
    /* put cursor on first non-blank of indented line */
    curwin->w_cursor.lnum = start_lnum;
    beginline(BL_SOL | BL_FIX);
  
    /* Mark changed lines so that they will be redrawn.  When Visual
     * highlighting was present, need to continue until the last line.  When
     * there is no change still need to remove the Visual highlighting. */
    if (last_changed != 0)
      changed_lines(first_changed, 0,
          oap->is_VIsual ? start_lnum + oap->line_count :
          last_changed + 1, 0L);
    else if (oap->is_VIsual)
      redraw_curbuf_later(INVERTED);
  
    if (oap->line_count > p_report) {
      i = oap->line_count - (i + 1);
      if (i == 1)
        MSG(_("1 line indented "));
      else
        smsg((char_u *)_("%" PRId64 " lines indented "), (int64_t)i);
    }
    /* set '[ and '] marks */
    curbuf->b_op_start = oap->start;
    curbuf->b_op_end = oap->end;
  }
  
  /*
   * Keep the last expression line here, for repeating.
   */
  static char_u   *expr_line = NULL;
  
  /*
   * Get an expression for the "\"=expr1" or "CTRL-R =expr1"
   * Returns '=' when OK, NUL otherwise.
   */
  int get_expr_register(void)
  {
    char_u      *new_line;
  
    new_line = getcmdline('=', 0L, 0);
    if (new_line == NULL)
      return NUL;
    if (*new_line == NUL)         /* use previous line */
      free(new_line);
    else
      set_expr_line(new_line);
    return '=';
  }
  
  /*
   * Set the expression for the '=' register.
   * Argument must be an allocated string.
   */
  void set_expr_line(char_u *new_line)
  {
    free(expr_line);
    expr_line = new_line;
  }
  
  /*
   * Get the result of the '=' register expression.
   * Returns a pointer to allocated memory, or NULL for failure.
   */
  char_u *get_expr_line(void)
  {
    char_u      *expr_copy;
    char_u      *rv;
    static int nested = 0;
  
    if (expr_line == NULL)
      return NULL;
  
    /* Make a copy of the expression, because evaluating it may cause it to be
     * changed. */
    expr_copy = vim_strsave(expr_line);
  
    /* When we are invoked recursively limit the evaluation to 10 levels.
     * Then return the string as-is. */
    if (nested >= 10)
      return expr_copy;
  
    ++nested;
    rv = eval_to_string(expr_copy, NULL, TRUE);
    --nested;
    free(expr_copy);
    return rv;
  }
  
  /*
   * Get the '=' register expression itself, without evaluating it.
   */
  char_u *get_expr_line_src(void)
  {
    if (expr_line == NULL)
      return NULL;
    return vim_strsave(expr_line);
  }
  
  /*
   * Check if 'regname' is a valid name of a yank register.
   * Note: There is no check for 0 (default register), caller should do this
   */
  int 
  valid_yank_reg (
      int regname,
      int writing                /* if TRUE check for writable registers */
  )
  {
    if (       (regname > 0 && ASCII_ISALNUM(regname))
               || (!writing && vim_strchr((char_u *)
                       "/.%#:="
                       , regname) != NULL)
               || regname == '"'
               || regname == '-'
               || regname == '_'
               || regname == '*'
               || regname == '+'
               )
      return TRUE;
    return FALSE;
  }
  
  /*
   * Set y_current and y_append, according to the value of "regname".
   * Cannot handle the '_' register.
   * Must only be called with a valid register name!
   *
   * If regname is 0 and writing, use register 0
   * If regname is 0 and reading, use previous register
   */
  void get_yank_register(int regname, int writing)
  {
    int i;
  
    y_append = FALSE;
    int unnamedclip = cb_flags & CB_UNNAMEDMASK;
    if ((regname == 0 || regname == '"') && !unnamedclip && !writing && y_previous != NULL) {
      y_current = y_previous;
      return;
    }
    i = regname;
    if (VIM_ISDIGIT(i))
      i -= '0';
    else if (ASCII_ISLOWER(i))
      i = CharOrdLow(i) + 10;
    else if (ASCII_ISUPPER(i)) {
      i = CharOrdUp(i) + 10;
      y_append = TRUE;
    } else if (regname == '-')
      i = DELETION_REGISTER;
    else if (regname == '*' || regname == '+')
      i = CLIP_REGISTER;
    else                  /* not 0-9, a-z, A-Z or '-': use register 0 */
      i = 0;
    y_current = &(y_regs[i]);
    if (writing)          /* remember the register we write into for do_put() */
      y_previous = y_current;
  }
  
  
  /*
   * Obtain the contents of a "normal" register. The register is made empty.
   * The returned pointer has allocated memory, use put_register() later.
   */
  void *
  get_register (
      int name,
      int copy               /* make a copy, if FALSE make register empty. */
  ) FUNC_ATTR_NONNULL_RET
  {
    get_yank_register(name, 0);
    get_clipboard(name);
  
    struct yankreg *reg = xmalloc(sizeof(struct yankreg));
    *reg = *y_current;
    if (copy) {
      if (reg->y_size == 0) {
        reg->y_array = NULL;
      } else {
        reg->y_array = xmalloc(reg->y_size * sizeof(char_u *));
        for (linenr_T i = 0; i < reg->y_size; ++i) {
          reg->y_array[i] = vim_strsave(y_current->y_array[i]);
        }
      }
    } else
      y_current->y_array = NULL;
  
    return (void *)reg;
  }
  
  /*
   * Put "reg" into register "name".  Free any previous contents and "reg".
   */
  void put_register(int name, void *reg)
  {
    get_yank_register(name, 0);
    free_yank_all();
    *y_current = *(struct yankreg *)reg;
    free(reg);
    set_clipboard(name);
  }
  
  /*
   * return TRUE if the current yank register has type MLINE
   */
  int yank_register_mline(int regname)
  {
    if (regname != 0 && !valid_yank_reg(regname, FALSE))
      return FALSE;
    if (regname == '_')           /* black hole is always empty */
      return FALSE;
    get_yank_register(regname, FALSE);
    return y_current->y_type == MLINE;
  }
  
  /*
   * Start or stop recording into a yank register.
   *
   * Return FAIL for failure, OK otherwise.
   */
  int do_record(int c)
  {
    char_u          *p;
    static int regname;
    struct yankreg  *old_y_previous, *old_y_current;
    int retval;
  
    if (Recording == FALSE) {         /* start recording */
      /* registers 0-9, a-z and " are allowed */
      if (c < 0 || (!ASCII_ISALNUM(c) && c != '"'))
        retval = FAIL;
      else {
        Recording = TRUE;
        showmode();
        regname = c;
        retval = OK;
      }
    } else {                        /* stop recording */
      /*
       * Get the recorded key hits.  K_SPECIAL and CSI will be escaped, this
       * needs to be removed again to put it in a register.  exec_reg then
       * adds the escaping back later.
       */
      Recording = FALSE;
      MSG("");
      p = get_recorded();
      if (p == NULL)
        retval = FAIL;
      else {
        /* Remove escaping for CSI and K_SPECIAL in multi-byte chars. */
        vim_unescape_csi(p);
  
        /*
         * We don't want to change the default register here, so save and
         * restore the current register name.
         */
        old_y_previous = y_previous;
        old_y_current = y_current;
  
        retval = stuff_yank(regname, p);
  
        y_previous = old_y_previous;
        y_current = old_y_current;
      }
    }
    return retval;
  }
  
  /*
   * Stuff string "p" into yank register "regname" as a single line (append if
   * uppercase).	"p" must have been alloced.
   *
   * return FAIL for failure, OK otherwise
   */
  static int stuff_yank(int regname, char_u *p)
  {
    /* check for read-only register */
    if (regname != 0 && !valid_yank_reg(regname, TRUE)) {
      free(p);
      return FAIL;
    }
    if (regname == '_') {             /* black hole: don't do anything */
      free(p);
      return OK;
    }
    get_yank_register(regname, TRUE);
    if (y_append && y_current->y_array != NULL) {
      char_u **pp = &(y_current->y_array[y_current->y_size - 1]);
      char_u *lp = xmalloc(STRLEN(*pp) + STRLEN(p) + 1);
      STRCPY(lp, *pp);
      // TODO(philix): use xstpcpy() in stuff_yank()
      STRCAT(lp, p);
      free(p);
      free(*pp);
      *pp = lp;
    } else {
      free_yank_all();
      y_current->y_array = (char_u **)xmalloc(sizeof(char_u *));
      y_current->y_array[0] = p;
      y_current->y_size = 1;
      y_current->y_type = MCHAR;      /* used to be MLINE, why? */
    }
    return OK;
  }
  
  static int execreg_lastc = NUL;
  
  /*
   * execute a yank register: copy it into the stuff buffer
   *
   * return FAIL for failure, OK otherwise
   */
  int 
  do_execreg (
      int regname,
      int colon,                      /* insert ':' before each line */
      int addcr,                      /* always add '\n' to end of line */
      int silent                     /* set "silent" flag in typeahead buffer */
  )
  {
    long i;
    char_u      *p;
    int retval = OK;
    int remap;
  
    if (regname == '@') {                 /* repeat previous one */
      if (execreg_lastc == NUL) {
        EMSG(_("E748: No previously used register"));
        return FAIL;
      }
      regname = execreg_lastc;
    }
    /* check for valid regname */
    if (regname == '%' || regname == '#' || !valid_yank_reg(regname, FALSE)) {
      emsg_invreg(regname);
      return FAIL;
    }
    execreg_lastc = regname;
  
    get_clipboard(regname);
  
    if (regname == '_')                   /* black hole: don't stuff anything */
      return OK;
  
    if (regname == ':') {                 /* use last command line */
      if (last_cmdline == NULL) {
        EMSG(_(e_nolastcmd));
        return FAIL;
      }
      free(new_last_cmdline);     /* don't keep the cmdline containing @: */
      new_last_cmdline = NULL;
      /* Escape all control characters with a CTRL-V */
      p = vim_strsave_escaped_ext(
          last_cmdline,
          (char_u *)
          "\001\002\003\004\005\006\007\010\011\012\013\014\015\016\017\020\021\022\023\024\025\026\027\030\031\032\033\034\035\036\037",
          Ctrl_V, FALSE);
      /* When in Visual mode "'<,'>" will be prepended to the command.
       * Remove it when it's already there. */
      if (VIsual_active && STRNCMP(p, "'<,'>", 5) == 0)
        retval = put_in_typebuf(p + 5, TRUE, TRUE, silent);
      else
        retval = put_in_typebuf(p, TRUE, TRUE, silent);
      free(p);
    } else if (regname == '=') {
      p = get_expr_line();
      if (p == NULL)
        return FAIL;
      retval = put_in_typebuf(p, TRUE, colon, silent);
      free(p);
    } else if (regname == '.') {        /* use last inserted text */
      p = get_last_insert_save();
      if (p == NULL) {
        EMSG(_(e_noinstext));
        return FAIL;
      }
      retval = put_in_typebuf(p, FALSE, colon, silent);
      free(p);
    } else {
      get_yank_register(regname, FALSE);
      if (y_current->y_array == NULL)
        return FAIL;
  
      /* Disallow remaping for ":@r". */
      remap = colon ? REMAP_NONE : REMAP_YES;
  
      /*
       * Insert lines into typeahead buffer, from last one to first one.
       */
      put_reedit_in_typebuf(silent);
      for (i = y_current->y_size; --i >= 0; ) {
        char_u *escaped;
  
        /* insert NL between lines and after last line if type is MLINE */
        if (y_current->y_type == MLINE || i < y_current->y_size - 1
            || addcr) {
          if (ins_typebuf((char_u *)"\n", remap, 0, TRUE, silent) == FAIL)
            return FAIL;
        }
        escaped = vim_strsave_escape_csi(y_current->y_array[i]);
        retval = ins_typebuf(escaped, remap, 0, TRUE, silent);
        free(escaped);
        if (retval == FAIL)
          return FAIL;
        if (colon && ins_typebuf((char_u *)":", remap, 0, TRUE, silent)
            == FAIL)
          return FAIL;
      }
      Exec_reg = TRUE;            /* disable the 'q' command */
    }
    return retval;
  }
  
  /*
   * If "restart_edit" is not zero, put it in the typeahead buffer, so that it's
   * used only after other typeahead has been processed.
   */
  static void put_reedit_in_typebuf(int silent)
  {
    char_u buf[3];
  
    if (restart_edit != NUL) {
      if (restart_edit == 'V') {
        buf[0] = 'g';
        buf[1] = 'R';
        buf[2] = NUL;
      } else {
        buf[0] = restart_edit == 'I' ? 'i' : restart_edit;
        buf[1] = NUL;
      }
      if (ins_typebuf(buf, REMAP_NONE, 0, TRUE, silent) == OK)
        restart_edit = NUL;
    }
  }
  
  /*
   * Insert register contents "s" into the typeahead buffer, so that it will be
   * executed again.
   * When "esc" is TRUE it is to be taken literally: Escape CSI characters and
   * no remapping.
   */
  static int 
  put_in_typebuf (
      char_u *s,
      int esc,
      int colon,                  /* add ':' before the line */
      int silent
  )
  {
    int retval = OK;
  
    put_reedit_in_typebuf(silent);
    if (colon)
      retval = ins_typebuf((char_u *)"\n", REMAP_NONE, 0, TRUE, silent);
    if (retval == OK) {
      char_u  *p;
  
      if (esc)
        p = vim_strsave_escape_csi(s);
      else
        p = s;
      if (p == NULL)
        retval = FAIL;
      else
        retval = ins_typebuf(p, esc ? REMAP_NONE : REMAP_YES,
            0, TRUE, silent);
      if (esc)
        free(p);
    }
    if (colon && retval == OK)
      retval = ins_typebuf((char_u *)":", REMAP_NONE, 0, TRUE, silent);
    return retval;
  }
  
  /*
   * Insert a yank register: copy it into the Read buffer.
   * Used by CTRL-R command and middle mouse button in insert mode.
   *
   * return FAIL for failure, OK otherwise
   */
  int 
  insert_reg (
      int regname,
      int literally                  /* insert literally, not as if typed */
  )
  {
    long i;
    int retval = OK;
    char_u      *arg;
    int allocated;
  
    /*
     * It is possible to get into an endless loop by having CTRL-R a in
     * register a and then, in insert mode, doing CTRL-R a.
     * If you hit CTRL-C, the loop will be broken here.
     */
    os_breakcheck();
    if (got_int)
      return FAIL;
  
    /* check for valid regname */
    if (regname != NUL && !valid_yank_reg(regname, FALSE))
      return FAIL;
  
    get_clipboard(regname);
  
    if (regname == '.')                   /* insert last inserted text */
      retval = stuff_inserted(NUL, 1L, TRUE);
    else if (get_spec_reg(regname, &arg, &allocated, TRUE)) {
      if (arg == NULL)
        return FAIL;
      stuffescaped(arg, literally);
      if (allocated)
        free(arg);
    } else {                            /* name or number register */
      get_yank_register(regname, FALSE);
      if (y_current->y_array == NULL)
        retval = FAIL;
      else {
        for (i = 0; i < y_current->y_size; ++i) {
          stuffescaped(y_current->y_array[i], literally);
          /*
           * Insert a newline between lines and after last line if
           * y_type is MLINE.
           */
          if (y_current->y_type == MLINE || i < y_current->y_size - 1)
            stuffcharReadbuff('\n');
        }
      }
    }
  
    return retval;
  }
  
  /*
   * Stuff a string into the typeahead buffer, such that edit() will insert it
   * literally ("literally" TRUE) or interpret is as typed characters.
   */
  static void stuffescaped(char_u *arg, int literally)
  {
    int c;
    char_u      *start;
  
    while (*arg != NUL) {
      /* Stuff a sequence of normal ASCII characters, that's fast.  Also
       * stuff K_SPECIAL to get the effect of a special key when "literally"
       * is TRUE. */
      start = arg;
      while ((*arg >= ' ' && *arg < DEL) || (*arg == K_SPECIAL && !literally))
        ++arg;
      if (arg > start)
        stuffReadbuffLen(start, (long)(arg - start));
  
      /* stuff a single special character */
      if (*arg != NUL) {
        if (has_mbyte)
          c = mb_cptr2char_adv(&arg);
        else
          c = *arg++;
        if (literally && ((c < ' ' && c != TAB) || c == DEL))
          stuffcharReadbuff(Ctrl_V);
        stuffcharReadbuff(c);
      }
    }
  }
  
  /*
   * If "regname" is a special register, return TRUE and store a pointer to its
   * value in "argp".
   */
  int 
  get_spec_reg (
      int regname,
      char_u **argp,
      int *allocated,         /* return: TRUE when value was allocated */
      int errmsg                     /* give error message when failing */
  )
  {
    int cnt;
  
    *argp = NULL;
    *allocated = FALSE;
    switch (regname) {
    case '%':                     /* file name */
      if (errmsg)
        check_fname();            /* will give emsg if not set */
      *argp = curbuf->b_fname;
      return TRUE;
  
    case '#':                     /* alternate file name */
      *argp = getaltfname(errmsg);                /* may give emsg if not set */
      return TRUE;
  
    case '=':                     /* result of expression */
      *argp = get_expr_line();
      *allocated = TRUE;
      return TRUE;
  
    case ':':                     /* last command line */
      if (last_cmdline == NULL && errmsg)
        EMSG(_(e_nolastcmd));
      *argp = last_cmdline;
      return TRUE;
  
    case '/':                     /* last search-pattern */
      if (last_search_pat() == NULL && errmsg)
        EMSG(_(e_noprevre));
      *argp = last_search_pat();
      return TRUE;
  
    case '.':                     /* last inserted text */
      *argp = get_last_insert_save();
      *allocated = TRUE;
      if (*argp == NULL && errmsg)
        EMSG(_(e_noinstext));
      return TRUE;
  
    case Ctrl_F:                  /* Filename under cursor */
    case Ctrl_P:                  /* Path under cursor, expand via "path" */
      if (!errmsg)
        return FALSE;
      *argp = file_name_at_cursor(FNAME_MESS | FNAME_HYP
          | (regname == Ctrl_P ? FNAME_EXP : 0), 1L, NULL);
      *allocated = TRUE;
      return TRUE;
  
    case Ctrl_W:                  /* word under cursor */
    case Ctrl_A:                  /* WORD (mnemonic All) under cursor */
      if (!errmsg)
        return FALSE;
      cnt = find_ident_under_cursor(argp, regname == Ctrl_W
          ?  (FIND_IDENT|FIND_STRING) : FIND_STRING);
      *argp = cnt ? vim_strnsave(*argp, cnt) : NULL;
      *allocated = TRUE;
      return TRUE;
  
    case '_':                     /* black hole: always empty */
      *argp = (char_u *)"";
      return TRUE;
    }
  
    return FALSE;
  }
  
  /*
   * Paste a yank register into the command line.
   * Only for non-special registers.
   * Used by CTRL-R command in command-line mode
   * insert_reg() can't be used here, because special characters from the
   * register contents will be interpreted as commands.
   *
   * return FAIL for failure, OK otherwise
   */
  int 
  cmdline_paste_reg (
      int regname,
      int literally,          /* Insert text literally instead of "as typed" */
      int remcr              /* don't add trailing CR */
  )
  {
    long i;
  
    get_yank_register(regname, FALSE);
    if (y_current->y_array == NULL)
      return FAIL;
  
    for (i = 0; i < y_current->y_size; ++i) {
      cmdline_paste_str(y_current->y_array[i], literally);
  
      /* Insert ^M between lines and after last line if type is MLINE.
       * Don't do this when "remcr" is TRUE and the next line is empty. */
      if (y_current->y_type == MLINE
          || (i < y_current->y_size - 1
              && !(remcr
                   && i == y_current->y_size - 2
                   && *y_current->y_array[i + 1] == NUL)))
        cmdline_paste_str((char_u *)"\r", literally);
  
      /* Check for CTRL-C, in case someone tries to paste a few thousand
       * lines and gets bored. */
      os_breakcheck();
      if (got_int)
        return FAIL;
    }
    return OK;
  }
  
  /*
   * Handle a delete operation.
   *
   * Return FAIL if undo failed, OK otherwise.
   */
  int op_delete(oparg_T *oap)
  {
    int n;
    linenr_T lnum;
    char_u              *ptr;
    char_u              *newp, *oldp;
    struct block_def bd;
    linenr_T old_lcount = curbuf->b_ml.ml_line_count;
    int did_yank = FALSE;
  
    if (curbuf->b_ml.ml_flags & ML_EMPTY)             /* nothing to do */
      return OK;
  
    /* Nothing to delete, return here.	Do prepare undo, for op_change(). */
    if (oap->empty)
      return u_save_cursor();
  
    if (!curbuf->b_p_ma) {
      EMSG(_(e_modifiable));
      return FAIL;
    }
  
    if (has_mbyte)
      mb_adjust_opend(oap);
  
    /*
     * Imitate the strange Vi behaviour: If the delete spans more than one
     * line and motion_type == MCHAR and the result is a blank line, make the
     * delete linewise.  Don't do this for the change command or Visual mode.
     */
    if (       oap->motion_type == MCHAR
               && !oap->is_VIsual
               && !oap->block_mode
               && oap->line_count > 1
               && oap->motion_force == NUL
               && oap->op_type == OP_DELETE) {
      ptr = ml_get(oap->end.lnum) + oap->end.col;
      if (*ptr != NUL)
        ptr += oap->inclusive;
      ptr = skipwhite(ptr);
      if (*ptr == NUL && inindent(0))
        oap->motion_type = MLINE;
    }
  
    /*
     * Check for trying to delete (e.g. "D") in an empty line.
     * Note: For the change operator it is ok.
     */
    if (       oap->motion_type == MCHAR
               && oap->line_count == 1
               && oap->op_type == OP_DELETE
               && *ml_get(oap->start.lnum) == NUL) {
      /*
       * It's an error to operate on an empty region, when 'E' included in
       * 'cpoptions' (Vi compatible).
       */
      if (virtual_op)
        /* Virtual editing: Nothing gets deleted, but we set the '[ and ']
         * marks as if it happened. */
        goto setmarks;
      if (vim_strchr(p_cpo, CPO_EMPTYREGION) != NULL)
        beep_flush();
      return OK;
    }
  
    /*
     * Do a yank of whatever we're about to delete.
     * If a yank register was specified, put the deleted text into that
     * register.  For the black hole register '_' don't yank anything.
     */
    if (oap->regname != '_') {
      if (oap->regname != 0) {
        /* check for read-only register */
        if (!( valid_yank_reg(oap->regname, TRUE) )) {
          beep_flush();
          return OK;
        }
        get_yank_register(oap->regname, TRUE);       /* yank into specif'd reg. */
        if (op_yank(oap, TRUE, FALSE) == OK)         /* yank without message */
          did_yank = TRUE;
      }
  
      /*
       * Put deleted text into register 1 and shift number registers if the
       * delete contains a line break, or when a regname has been specified.
       */
      if (oap->regname != 0 || oap->motion_type == MLINE
          || oap->line_count > 1 || oap->use_reg_one) {
        y_current = &y_regs[9];
        free_yank_all();                          /* free register nine */
        for (n = 9; n > 1; --n)
          y_regs[n] = y_regs[n - 1];
        y_previous = y_current = &y_regs[1];
        y_regs[1].y_array = NULL;                 /* set register one to empty */
        if (op_yank(oap, TRUE, FALSE) == OK)
          did_yank = TRUE;
      }
  
      /* Yank into small delete register when no named register specified
       * and the delete is within one line. */
      if (oap->regname == 0 && oap->motion_type != MLINE
          && oap->line_count == 1) {
        oap->regname = '-';
        get_yank_register(oap->regname, TRUE);
        if (op_yank(oap, TRUE, FALSE) == OK)
          did_yank = TRUE;
        oap->regname = 0;
      }
  
      if(oap->regname == 0 && did_yank) {
        set_clipboard(CB_LATEST);
      }
      /*
       * If there's too much stuff to fit in the yank register, then get a
       * confirmation before doing the delete. This is crude, but simple.
       * And it avoids doing a delete of something we can't put back if we
       * want.
       */
      if (!did_yank) {
        int msg_silent_save = msg_silent;
  
        msg_silent = 0;           /* must display the prompt */
        n = ask_yesno((char_u *)_("cannot yank; delete anyway"), TRUE);
        msg_silent = msg_silent_save;
        if (n != 'y') {
          EMSG(_(e_abort));
          return FAIL;
        }
      }
    }
  
    /*
     * block mode delete
     */
    if (oap->block_mode) {
      if (u_save((linenr_T)(oap->start.lnum - 1),
              (linenr_T)(oap->end.lnum + 1)) == FAIL)
        return FAIL;
  
      for (lnum = curwin->w_cursor.lnum; lnum <= oap->end.lnum; ++lnum) {
        block_prep(oap, &bd, lnum, TRUE);
        if (bd.textlen == 0)              /* nothing to delete */
          continue;
  
        /* Adjust cursor position for tab replaced by spaces and 'lbr'. */
        if (lnum == curwin->w_cursor.lnum) {
          curwin->w_cursor.col = bd.textcol + bd.startspaces;
          curwin->w_cursor.coladd = 0;
        }
  
        /* n == number of chars deleted
         * If we delete a TAB, it may be replaced by several characters.
         * Thus the number of characters may increase!
         */
        n = bd.textlen - bd.startspaces - bd.endspaces;
        oldp = ml_get(lnum);
        newp = (char_u *) xmalloc((size_t)(STRLEN(oldp) + 1 - n));
        /* copy up to deleted part */
        memmove(newp, oldp, (size_t)bd.textcol);
        /* insert spaces */
        memset(newp + bd.textcol, ' ',
            (size_t)(bd.startspaces + bd.endspaces));
        /* copy the part after the deleted part */
        oldp += bd.textcol + bd.textlen;
        STRMOVE(newp + bd.textcol + bd.startspaces + bd.endspaces, oldp);
        /* replace the line */
        ml_replace(lnum, newp, FALSE);
      }
  
      check_cursor_col();
      changed_lines(curwin->w_cursor.lnum, curwin->w_cursor.col,
          oap->end.lnum + 1, 0L);
      oap->line_count = 0;            /* no lines deleted */
    } else if (oap->motion_type == MLINE) {
      if (oap->op_type == OP_CHANGE) {
        /* Delete the lines except the first one.  Temporarily move the
         * cursor to the next line.  Save the current line number, if the
         * last line is deleted it may be changed.
         */
        if (oap->line_count > 1) {
          lnum = curwin->w_cursor.lnum;
          ++curwin->w_cursor.lnum;
          del_lines((long)(oap->line_count - 1), TRUE);
          curwin->w_cursor.lnum = lnum;
        }
        if (u_save_cursor() == FAIL)
          return FAIL;
        if (curbuf->b_p_ai) {                 /* don't delete indent */
          beginline(BL_WHITE);                /* cursor on first non-white */
          did_ai = TRUE;                      /* delete the indent when ESC hit */
          ai_col = curwin->w_cursor.col;
        } else
          beginline(0);                       /* cursor in column 0 */
        truncate_line(FALSE);         /* delete the rest of the line */
                                      /* leave cursor past last char in line */
        if (oap->line_count > 1)
          u_clearline();              /* "U" command not possible after "2cc" */
      } else {
        del_lines(oap->line_count, TRUE);
        beginline(BL_WHITE | BL_FIX);
        u_clearline();            /* "U" command not possible after "dd" */
      }
    } else {
      if (virtual_op) {
        int endcol = 0;
  
        /* For virtualedit: break the tabs that are partly included. */
        if (gchar_pos(&oap->start) == '\t') {
          if (u_save_cursor() == FAIL)            /* save first line for undo */
            return FAIL;
          if (oap->line_count == 1)
            endcol = getviscol2(oap->end.col, oap->end.coladd);
          coladvance_force(getviscol2(oap->start.col, oap->start.coladd));
          oap->start = curwin->w_cursor;
          if (oap->line_count == 1) {
            coladvance(endcol);
            oap->end.col = curwin->w_cursor.col;
            oap->end.coladd = curwin->w_cursor.coladd;
            curwin->w_cursor = oap->start;
          }
        }
  
        /* Break a tab only when it's included in the area. */
        if (gchar_pos(&oap->end) == '\t'
            && oap->end.coladd == 0
            && oap->inclusive) {
          /* save last line for undo */
          if (u_save((linenr_T)(oap->end.lnum - 1),
                  (linenr_T)(oap->end.lnum + 1)) == FAIL)
            return FAIL;
          curwin->w_cursor = oap->end;
          coladvance_force(getviscol2(oap->end.col, oap->end.coladd));
          oap->end = curwin->w_cursor;
          curwin->w_cursor = oap->start;
        }
      }
  
      if (oap->line_count == 1) {         /* delete characters within one line */
        if (u_save_cursor() == FAIL)              /* save line for undo */
          return FAIL;
  
        /* if 'cpoptions' contains '$', display '$' at end of change */
        if (           vim_strchr(p_cpo, CPO_DOLLAR) != NULL
                       && oap->op_type == OP_CHANGE
                       && oap->end.lnum == curwin->w_cursor.lnum
                       && !oap->is_VIsual
                       )
          display_dollar(oap->end.col - !oap->inclusive);
  
        n = oap->end.col - oap->start.col + 1 - !oap->inclusive;
  
        if (virtual_op) {
          /* fix up things for virtualedit-delete:
           * break the tabs which are going to get in our way
           */
          char_u          *curline = get_cursor_line_ptr();
          int len = (int)STRLEN(curline);
  
          if (oap->end.coladd != 0
              && (int)oap->end.col >= len - 1
              && !(oap->start.coladd && (int)oap->end.col >= len - 1))
            n++;
          /* Delete at least one char (e.g, when on a control char). */
          if (n == 0 && oap->start.coladd != oap->end.coladd)
            n = 1;
  
          /* When deleted a char in the line, reset coladd. */
          if (gchar_cursor() != NUL)
            curwin->w_cursor.coladd = 0;
        }
        if (oap->op_type == OP_DELETE
            && oap->inclusive
            && oap->end.lnum == curbuf->b_ml.ml_line_count
            && n > (int)STRLEN(ml_get(oap->end.lnum))) {
          /* Special case: gH<Del> deletes the last line. */
          del_lines(1L, FALSE);
        } else {
          (void)del_bytes((long)n, !virtual_op, oap->op_type == OP_DELETE
              && !oap->is_VIsual
              );
        }
      } else {                          /* delete characters between lines */
        pos_T curpos;
        int delete_last_line;
  
        /* save deleted and changed lines for undo */
        if (u_save((linenr_T)(curwin->w_cursor.lnum - 1),
                (linenr_T)(curwin->w_cursor.lnum + oap->line_count)) == FAIL)
          return FAIL;
  
        delete_last_line = (oap->end.lnum == curbuf->b_ml.ml_line_count);
        truncate_line(TRUE);              /* delete from cursor to end of line */
  
        curpos = curwin->w_cursor;        /* remember curwin->w_cursor */
        ++curwin->w_cursor.lnum;
        del_lines((long)(oap->line_count - 2), FALSE);
  
        if (delete_last_line)
          oap->end.lnum = curbuf->b_ml.ml_line_count;
  
        n = (oap->end.col + 1 - !oap->inclusive);
        if (oap->inclusive && delete_last_line
            && n > (int)STRLEN(ml_get(oap->end.lnum))) {
          /* Special case: gH<Del> deletes the last line. */
          del_lines(1L, FALSE);
          curwin->w_cursor = curpos;              /* restore curwin->w_cursor */
          if (curwin->w_cursor.lnum > curbuf->b_ml.ml_line_count)
            curwin->w_cursor.lnum = curbuf->b_ml.ml_line_count;
        } else {
          /* delete from start of line until op_end */
          curwin->w_cursor.col = 0;
          (void)del_bytes((long)n, !virtual_op, oap->op_type == OP_DELETE
              && !oap->is_VIsual
              );
          curwin->w_cursor = curpos;              /* restore curwin->w_cursor */
        }
        if (curwin->w_cursor.lnum < curbuf->b_ml.ml_line_count) {
          do_join(2, FALSE, FALSE, FALSE, false);
        }
      }
    }
  
    msgmore(curbuf->b_ml.ml_line_count - old_lcount);
  
  setmarks:
    if (oap->block_mode) {
      curbuf->b_op_end.lnum = oap->end.lnum;
      curbuf->b_op_end.col = oap->start.col;
    } else
      curbuf->b_op_end = oap->start;
    curbuf->b_op_start = oap->start;
  
    return OK;
  }
  
  /*
   * Adjust end of operating area for ending on a multi-byte character.
   * Used for deletion.
   */
  static void mb_adjust_opend(oparg_T *oap)
  {
    char_u      *p;
  
    if (oap->inclusive) {
      p = ml_get(oap->end.lnum);
      oap->end.col += mb_tail_off(p, p + oap->end.col);
    }
  }
  
  /*
   * Put character 'c' at position 'lp'
   */
  static inline void pchar(pos_T lp, int c)
  {
      *(ml_get_buf(curbuf, lp.lnum, TRUE) + lp.col) = c;;
  }
  
  /*
   * Replace a whole area with one character.
   */
  int op_replace(oparg_T *oap, int c)
  {
    int n, numc;
    int num_chars;
    char_u              *newp, *oldp;
    size_t oldlen;
    struct block_def bd;
    char_u              *after_p = NULL;
    int had_ctrl_v_cr = (c == -1 || c == -2);
  
    if ((curbuf->b_ml.ml_flags & ML_EMPTY ) || oap->empty)
      return OK;              /* nothing to do */
  
    if (had_ctrl_v_cr)
      c = (c == -1 ? '\r' : '\n');
  
    if (has_mbyte)
      mb_adjust_opend(oap);
  
    if (u_save((linenr_T)(oap->start.lnum - 1),
            (linenr_T)(oap->end.lnum + 1)) == FAIL)
      return FAIL;
  
    /*
     * block mode replace
     */
    if (oap->block_mode) {
      bd.is_MAX = (curwin->w_curswant == MAXCOL);
      for (; curwin->w_cursor.lnum <= oap->end.lnum; ++curwin->w_cursor.lnum) {
        curwin->w_cursor.col = 0;        /* make sure cursor position is valid */
        block_prep(oap, &bd, curwin->w_cursor.lnum, TRUE);
        if (bd.textlen == 0 && (!virtual_op || bd.is_MAX))
          continue;                   /* nothing to replace */
  
        /* n == number of extra chars required
         * If we split a TAB, it may be replaced by several characters.
         * Thus the number of characters may increase!
         */
        /* If the range starts in virtual space, count the initial
         * coladd offset as part of "startspaces" */
        if (virtual_op && bd.is_short && *bd.textstart == NUL) {
          pos_T vpos;
  
          vpos.lnum = curwin->w_cursor.lnum;
          getvpos(&vpos, oap->start_vcol);
          bd.startspaces += vpos.coladd;
          n = bd.startspaces;
        } else
          /* allow for pre spaces */
          n = (bd.startspaces ? bd.start_char_vcols - 1 : 0);
  
        /* allow for post spp */
        n += (bd.endspaces
              && !bd.is_oneChar
              && bd.end_char_vcols > 0) ? bd.end_char_vcols - 1 : 0;
        /* Figure out how many characters to replace. */
        numc = oap->end_vcol - oap->start_vcol + 1;
        if (bd.is_short && (!virtual_op || bd.is_MAX))
          numc -= (oap->end_vcol - bd.end_vcol) + 1;
  
        /* A double-wide character can be replaced only up to half the
         * times. */
        if ((*mb_char2cells)(c) > 1) {
          if ((numc & 1) && !bd.is_short) {
            ++bd.endspaces;
            ++n;
          }
          numc = numc / 2;
        }
  
        /* Compute bytes needed, move character count to num_chars. */
        num_chars = numc;
        numc *= (*mb_char2len)(c);
        /* oldlen includes textlen, so don't double count */
        n += numc - bd.textlen;
  
        oldp = get_cursor_line_ptr();
        oldlen = STRLEN(oldp);
        newp = (char_u *) xmalloc((size_t)(oldlen + 1 + n));
        memset(newp, NUL, (size_t)(oldlen + 1 + n));
        /* copy up to deleted part */
        memmove(newp, oldp, (size_t)bd.textcol);
        oldp += bd.textcol + bd.textlen;
        /* insert pre-spaces */
        memset(newp + bd.textcol, ' ', (size_t)bd.startspaces);
        /* insert replacement chars CHECK FOR ALLOCATED SPACE */
        /* -1/-2 is used for entering CR literally. */
        if (had_ctrl_v_cr || (c != '\r' && c != '\n')) {
          if (has_mbyte) {
            n = (int)STRLEN(newp);
            while (--num_chars >= 0)
              n += (*mb_char2bytes)(c, newp + n);
          } else
            memset(newp + STRLEN(newp), c, (size_t)numc);
          if (!bd.is_short) {
            /* insert post-spaces */
            memset(newp + STRLEN(newp), ' ', (size_t)bd.endspaces);
            /* copy the part after the changed part */
            STRMOVE(newp + STRLEN(newp), oldp);
          }
        } else {
          /* Replacing with \r or \n means splitting the line. */
          after_p = (char_u *) xmalloc((size_t)(oldlen + 1 + n - STRLEN(newp)));
          STRMOVE(after_p, oldp);
        }
        /* replace the line */
        ml_replace(curwin->w_cursor.lnum, newp, FALSE);
        if (after_p != NULL) {
          ml_append(curwin->w_cursor.lnum++, after_p, 0, FALSE);
          appended_lines_mark(curwin->w_cursor.lnum, 1L);
          oap->end.lnum++;
          free(after_p);
        }
      }
    } else {
      /*
       * MCHAR and MLINE motion replace.
       */
      if (oap->motion_type == MLINE) {
        oap->start.col = 0;
        curwin->w_cursor.col = 0;
        oap->end.col = (colnr_T)STRLEN(ml_get(oap->end.lnum));
        if (oap->end.col)
          --oap->end.col;
      } else if (!oap->inclusive)
        dec(&(oap->end));
  
      while (ltoreq(curwin->w_cursor, oap->end)) {
        n = gchar_cursor();
        if (n != NUL) {
          if ((*mb_char2len)(c) > 1 || (*mb_char2len)(n) > 1) {
            /* This is slow, but it handles replacing a single-byte
             * with a multi-byte and the other way around. */
            if (curwin->w_cursor.lnum == oap->end.lnum)
              oap->end.col += (*mb_char2len)(c) - (*mb_char2len)(n);
            n = State;
            State = REPLACE;
            ins_char(c);
            State = n;
            /* Backup to the replaced character. */
            dec_cursor();
          } else {
            if (n == TAB) {
              int end_vcol = 0;
  
              if (curwin->w_cursor.lnum == oap->end.lnum) {
                /* oap->end has to be recalculated when
                 * the tab breaks */
                end_vcol = getviscol2(oap->end.col,
                    oap->end.coladd);
              }
              coladvance_force(getviscol());
              if (curwin->w_cursor.lnum == oap->end.lnum)
                getvpos(&oap->end, end_vcol);
            }
            pchar(curwin->w_cursor, c);
          }
        } else if (virtual_op && curwin->w_cursor.lnum == oap->end.lnum) {
          int virtcols = oap->end.coladd;
  
          if (curwin->w_cursor.lnum == oap->start.lnum
              && oap->start.col == oap->end.col && oap->start.coladd)
            virtcols -= oap->start.coladd;
  
          /* oap->end has been trimmed so it's effectively inclusive;
           * as a result an extra +1 must be counted so we don't
           * trample the NUL byte. */
          coladvance_force(getviscol2(oap->end.col, oap->end.coladd) + 1);
          curwin->w_cursor.col -= (virtcols + 1);
          for (; virtcols >= 0; virtcols--) {
            pchar(curwin->w_cursor, c);
            if (inc(&curwin->w_cursor) == -1)
              break;
          }
        }
  
        /* Advance to next character, stop at the end of the file. */
        if (inc_cursor() == -1)
          break;
      }
    }
  
    curwin->w_cursor = oap->start;
    check_cursor();
    changed_lines(oap->start.lnum, oap->start.col, oap->end.lnum + 1, 0L);
  
    /* Set "'[" and "']" marks. */
    curbuf->b_op_start = oap->start;
    curbuf->b_op_end = oap->end;
  
    return OK;
  }
  
  
  /*
   * Handle the (non-standard vi) tilde operator.  Also for "gu", "gU" and "g?".
   */
  void op_tilde(oparg_T *oap)
  {
    pos_T pos;
    struct block_def bd;
    int did_change = FALSE;
  
    if (u_save((linenr_T)(oap->start.lnum - 1),
            (linenr_T)(oap->end.lnum + 1)) == FAIL)
      return;
  
    pos = oap->start;
    if (oap->block_mode) {                    /* Visual block mode */
      for (; pos.lnum <= oap->end.lnum; ++pos.lnum) {
        int one_change;
  
        block_prep(oap, &bd, pos.lnum, FALSE);
        pos.col = bd.textcol;
        one_change = swapchars(oap->op_type, &pos, bd.textlen);
        did_change |= one_change;
  
      }
      if (did_change)
        changed_lines(oap->start.lnum, 0, oap->end.lnum + 1, 0L);
    } else {                                /* not block mode */
      if (oap->motion_type == MLINE) {
        oap->start.col = 0;
        pos.col = 0;
        oap->end.col = (colnr_T)STRLEN(ml_get(oap->end.lnum));
        if (oap->end.col)
          --oap->end.col;
      } else if (!oap->inclusive)
        dec(&(oap->end));
  
      if (pos.lnum == oap->end.lnum)
        did_change = swapchars(oap->op_type, &pos,
            oap->end.col - pos.col + 1);
      else
        for (;; ) {
          did_change |= swapchars(oap->op_type, &pos,
              pos.lnum == oap->end.lnum ? oap->end.col + 1 :
              (int)STRLEN(ml_get_pos(&pos)));
          if (ltoreq(oap->end, pos) || inc(&pos) == -1)
            break;
        }
      if (did_change) {
        changed_lines(oap->start.lnum, oap->start.col, oap->end.lnum + 1,
            0L);
      }
    }
  
    if (!did_change && oap->is_VIsual)
      /* No change: need to remove the Visual selection */
      redraw_curbuf_later(INVERTED);
  
    /*
     * Set '[ and '] marks.
     */
    curbuf->b_op_start = oap->start;
    curbuf->b_op_end = oap->end;
  
    if (oap->line_count > p_report) {
      if (oap->line_count == 1)
        MSG(_("1 line changed"));
      else
        smsg((char_u *)_("%" PRId64 " lines changed"), (int64_t)oap->line_count);
    }
  }
  
  /*
   * Invoke swapchar() on "length" bytes at position "pos".
   * "pos" is advanced to just after the changed characters.
   * "length" is rounded up to include the whole last multi-byte character.
   * Also works correctly when the number of bytes changes.
   * Returns TRUE if some character was changed.
   */
  static int swapchars(int op_type, pos_T *pos, int length)
  {
    int todo;
    int did_change = 0;
  
    for (todo = length; todo > 0; --todo) {
      if (has_mbyte) {
        int len = (*mb_ptr2len)(ml_get_pos(pos));
  
        /* we're counting bytes, not characters */
        if (len > 0)
          todo -= len - 1;
      }
      did_change |= swapchar(op_type, pos);
      if (inc(pos) == -1)        /* at end of file */
        break;
    }
    return did_change;
  }
  
  /*
   * If op_type == OP_UPPER: make uppercase,
   * if op_type == OP_LOWER: make lowercase,
   * if op_type == OP_ROT13: do rot13 encoding,
   * else swap case of character at 'pos'
   * returns TRUE when something actually changed.
   */
  int swapchar(int op_type, pos_T *pos)
  {
    int c;
    int nc;
  
    c = gchar_pos(pos);
  
    /* Only do rot13 encoding for ASCII characters. */
    if (c >= 0x80 && op_type == OP_ROT13)
      return FALSE;
  
    if (op_type == OP_UPPER && c == 0xdf
        && (enc_latin1like || STRCMP(p_enc, "iso-8859-2") == 0)) {
      pos_T sp = curwin->w_cursor;
  
      /* Special handling of German sharp s: change to "SS". */
      curwin->w_cursor = *pos;
      del_char(FALSE);
      ins_char('S');
      ins_char('S');
      curwin->w_cursor = sp;
      inc(pos);
    }
  
    if (enc_dbcs != 0 && c >= 0x100)      /* No lower/uppercase letter */
      return FALSE;
    nc = c;
    if (vim_islower(c)) {
      if (op_type == OP_ROT13)
        nc = ROT13(c, 'a');
      else if (op_type != OP_LOWER)
        nc = vim_toupper(c);
    } else if (vim_isupper(c)) {
      if (op_type == OP_ROT13)
        nc = ROT13(c, 'A');
      else if (op_type != OP_UPPER)
        nc = vim_tolower(c);
    }
    if (nc != c) {
      if (enc_utf8 && (c >= 0x80 || nc >= 0x80)) {
        pos_T sp = curwin->w_cursor;
  
        curwin->w_cursor = *pos;
        /* don't use del_char(), it also removes composing chars */
        del_bytes(utf_ptr2len(get_cursor_pos_ptr()), FALSE, FALSE);
        ins_char(nc);
        curwin->w_cursor = sp;
      } else
        pchar(*pos, nc);
      return TRUE;
    }
    return FALSE;
  }
  
  /*
   * op_insert - Insert and append operators for Visual mode.
   */
  void op_insert(oparg_T *oap, long count1)
  {
    long ins_len, pre_textlen = 0;
    char_u              *firstline, *ins_text;
    struct block_def bd;
    int i;
  
    /* edit() changes this - record it for OP_APPEND */
    bd.is_MAX = (curwin->w_curswant == MAXCOL);
  
    /* vis block is still marked. Get rid of it now. */
    curwin->w_cursor.lnum = oap->start.lnum;
    update_screen(INVERTED);
  
    if (oap->block_mode) {
      /* When 'virtualedit' is used, need to insert the extra spaces before
       * doing block_prep().  When only "block" is used, virtual edit is
       * already disabled, but still need it when calling
       * coladvance_force(). */
      if (curwin->w_cursor.coladd > 0) {
        int old_ve_flags = ve_flags;
  
        ve_flags = VE_ALL;
        if (u_save_cursor() == FAIL)
          return;
        coladvance_force(oap->op_type == OP_APPEND
            ? oap->end_vcol + 1 : getviscol());
        if (oap->op_type == OP_APPEND)
          --curwin->w_cursor.col;
        ve_flags = old_ve_flags;
      }
      /* Get the info about the block before entering the text */
      block_prep(oap, &bd, oap->start.lnum, TRUE);
      firstline = ml_get(oap->start.lnum) + bd.textcol;
      if (oap->op_type == OP_APPEND)
        firstline += bd.textlen;
      pre_textlen = (long)STRLEN(firstline);
    }
  
    if (oap->op_type == OP_APPEND) {
      if (oap->block_mode
          && curwin->w_cursor.coladd == 0
          ) {
        /* Move the cursor to the character right of the block. */
        curwin->w_set_curswant = TRUE;
        while (*get_cursor_pos_ptr() != NUL
               && (curwin->w_cursor.col < bd.textcol + bd.textlen))
          ++curwin->w_cursor.col;
        if (bd.is_short && !bd.is_MAX) {
          /* First line was too short, make it longer and adjust the
           * values in "bd". */
          if (u_save_cursor() == FAIL)
            return;
          for (i = 0; i < bd.endspaces; ++i)
            ins_char(' ');
          bd.textlen += bd.endspaces;
        }
      } else {
        curwin->w_cursor = oap->end;
        check_cursor_col();
  
        /* Works just like an 'i'nsert on the next character. */
        if (!lineempty(curwin->w_cursor.lnum)
            && oap->start_vcol != oap->end_vcol)
          inc_cursor();
      }
    }
  
    edit(NUL, FALSE, (linenr_T)count1);
  
    /* If user has moved off this line, we don't know what to do, so do
     * nothing.
     * Also don't repeat the insert when Insert mode ended with CTRL-C. */
    if (curwin->w_cursor.lnum != oap->start.lnum || got_int)
      return;
  
    if (oap->block_mode) {
      struct block_def bd2;
  
      /* The user may have moved the cursor before inserting something, try
       * to adjust the block for that. */
      if (oap->start.lnum == curbuf->b_op_start_orig.lnum && !bd.is_MAX) {
        if (oap->op_type == OP_INSERT
            && oap->start.col + oap->start.coladd
               != curbuf->b_op_start_orig.col + curbuf->b_op_start_orig.coladd) {
          oap->start.col = curbuf->b_op_start_orig.col;
          pre_textlen -= getviscol2(oap->start.col, oap->start.coladd)
                         - oap->start_vcol;
          oap->start_vcol = getviscol2(oap->start.col, oap->start.coladd);
        } else if (oap->op_type == OP_APPEND
                   && oap->end.col + oap->end.coladd
                      >= curbuf->b_op_start_orig.col
                         + curbuf->b_op_start_orig.coladd) {
          oap->start.col = curbuf->b_op_start_orig.col;
          /* reset pre_textlen to the value of OP_INSERT */
          pre_textlen += bd.textlen;
          pre_textlen -= getviscol2(oap->start.col, oap->start.coladd)
                         - oap->start_vcol;
          oap->start_vcol = getviscol2(oap->start.col, oap->start.coladd);
          oap->op_type = OP_INSERT;
        }
      }
  
      /*
       * Spaces and tabs in the indent may have changed to other spaces and
       * tabs.  Get the starting column again and correct the length.
       * Don't do this when "$" used, end-of-line will have changed.
       */
      block_prep(oap, &bd2, oap->start.lnum, TRUE);
      if (!bd.is_MAX || bd2.textlen < bd.textlen) {
        if (oap->op_type == OP_APPEND) {
          pre_textlen += bd2.textlen - bd.textlen;
          if (bd2.endspaces)
            --bd2.textlen;
        }
        bd.textcol = bd2.textcol;
        bd.textlen = bd2.textlen;
      }
  
      /*
       * Subsequent calls to ml_get() flush the firstline data - take a
       * copy of the required string.
       */
      firstline = ml_get(oap->start.lnum) + bd.textcol;
      if (oap->op_type == OP_APPEND)
        firstline += bd.textlen;
      if (pre_textlen >= 0
          && (ins_len = (long)STRLEN(firstline) - pre_textlen) > 0) {
        ins_text = vim_strnsave(firstline, (int)ins_len);
        /* block handled here */
        if (u_save(oap->start.lnum,
                (linenr_T)(oap->end.lnum + 1)) == OK)
          block_insert(oap, ins_text, (oap->op_type == OP_INSERT),
              &bd);
  
        curwin->w_cursor.col = oap->start.col;
        check_cursor();
        free(ins_text);
      }
    }
  }
  
  /*
   * op_change - handle a change operation
   *
   * return TRUE if edit() returns because of a CTRL-O command
   */
  int op_change(oparg_T *oap)
  {
    colnr_T l;
    int retval;
    long offset;
    linenr_T linenr;
    long ins_len;
    long pre_textlen = 0;
    long pre_indent = 0;
    char_u              *firstline;
    char_u              *ins_text, *newp, *oldp;
    struct block_def bd;
  
    l = oap->start.col;
    if (oap->motion_type == MLINE) {
      l = 0;
      if (!p_paste && curbuf->b_p_si
          && !curbuf->b_p_cin
          )
        can_si = TRUE;            /* It's like opening a new line, do si */
    }
  
    /* First delete the text in the region.  In an empty buffer only need to
     * save for undo */
    if (curbuf->b_ml.ml_flags & ML_EMPTY) {
      if (u_save_cursor() == FAIL)
        return FALSE;
    } else if (op_delete(oap) == FAIL)
      return FALSE;
  
    if ((l > curwin->w_cursor.col) && !lineempty(curwin->w_cursor.lnum)
        && !virtual_op)
      inc_cursor();
  
    /* check for still on same line (<CR> in inserted text meaningless) */
    /* skip blank lines too */
    if (oap->block_mode) {
      /* Add spaces before getting the current line length. */
      if (virtual_op && (curwin->w_cursor.coladd > 0
                         || gchar_cursor() == NUL))
        coladvance_force(getviscol());
      firstline = ml_get(oap->start.lnum);
      pre_textlen = (long)STRLEN(firstline);
      pre_indent = (long)(skipwhite(firstline) - firstline);
      bd.textcol = curwin->w_cursor.col;
    }
  
    if (oap->motion_type == MLINE)
      fix_indent();
  
    retval = edit(NUL, FALSE, (linenr_T)1);
  
    /*
     * In Visual block mode, handle copying the new text to all lines of the
     * block.
     * Don't repeat the insert when Insert mode ended with CTRL-C.
     */
    if (oap->block_mode && oap->start.lnum != oap->end.lnum && !got_int) {
      /* Auto-indenting may have changed the indent.  If the cursor was past
       * the indent, exclude that indent change from the inserted text. */
      firstline = ml_get(oap->start.lnum);
      if (bd.textcol > (colnr_T)pre_indent) {
        long new_indent = (long)(skipwhite(firstline) - firstline);
  
        pre_textlen += new_indent - pre_indent;
        bd.textcol += new_indent - pre_indent;
      }
  
      ins_len = (long)STRLEN(firstline) - pre_textlen;
      if (ins_len > 0) {
        /* Subsequent calls to ml_get() flush the firstline data - take a
         * copy of the inserted text.  */
        ins_text = (char_u *) xmalloc((size_t)(ins_len + 1));
        STRLCPY(ins_text, firstline + bd.textcol, ins_len + 1);
        for (linenr = oap->start.lnum + 1; linenr <= oap->end.lnum;
             linenr++) {
          block_prep(oap, &bd, linenr, TRUE);
          if (!bd.is_short || virtual_op) {
            pos_T vpos;
  
            /* If the block starts in virtual space, count the
             * initial coladd offset as part of "startspaces" */
            if (bd.is_short) {
              vpos.lnum = linenr;
              (void)getvpos(&vpos, oap->start_vcol);
            } else
              vpos.coladd = 0;
            oldp = ml_get(linenr);
            newp = (char_u *) xmalloc((size_t)(STRLEN(oldp) + vpos.coladd + ins_len + 1));
            /* copy up to block start */
            memmove(newp, oldp, (size_t)bd.textcol);
            offset = bd.textcol;
            memset(newp + offset, ' ', (size_t)vpos.coladd);
            offset += vpos.coladd;
            memmove(newp + offset, ins_text, (size_t)ins_len);
            offset += ins_len;
            oldp += bd.textcol;
            STRMOVE(newp + offset, oldp);
            ml_replace(linenr, newp, FALSE);
          }
        }
        check_cursor();
        changed_lines(oap->start.lnum + 1, 0, oap->end.lnum + 1, 0L);
        free(ins_text);
      }
    }
  
    return retval;
  }
  
  /*
   * set all the yank registers to empty (called from main())
   */
  void init_yank(void)
  {
    int i;
  
    for (i = 0; i < NUM_REGISTERS; ++i)
      y_regs[i].y_array = NULL;
  }
  
  #if defined(EXITFREE)
  void clear_registers(void)
  {
    int i;
  
    for (i = 0; i < NUM_REGISTERS; ++i) {
      y_current = &y_regs[i];
      if (y_current->y_array != NULL)
        free_yank_all();
    }
  }
  
  #endif
  
  /*
   * Free "n" lines from the current yank register.
   * Called for normal freeing and in case of error.
   */
  static void free_yank(long n)
  {
    if (y_current->y_array != NULL) {
      long i;
  
      for (i = n; --i >= 0; ) {
        free(y_current->y_array[i]);
      }
      free(y_current->y_array);
      y_current->y_array = NULL;
    }
  }
  
  static void free_yank_all(void)
  {
    free_yank(y_current->y_size);
  }
  
  /*
   * Yank the text between "oap->start" and "oap->end" into a yank register.
   * If we are to append (uppercase register), we first yank into a new yank
   * register and then concatenate the old and the new one (so we keep the old
   * one in case of out-of-memory).
   *
   * Return FAIL for failure, OK otherwise.
   */
  int op_yank(oparg_T *oap, int deleting, int mess)
  {
    long y_idx;                           /* index in y_array[] */
    struct yankreg      *curr;            /* copy of y_current */
    struct yankreg newreg;                /* new yank register when appending */
    char_u              **new_ptr;
    linenr_T lnum;                        /* current line number */
    long j;
    int yanktype = oap->motion_type;
    long yanklines = oap->line_count;
    linenr_T yankendlnum = oap->end.lnum;
    char_u              *p;
    char_u              *pnew;
    struct block_def bd;
  
    /* check for read-only register */
    if (oap->regname != 0 && !valid_yank_reg(oap->regname, TRUE)) {
      beep_flush();
      return FAIL;
    }
    if (oap->regname == '_')          /* black hole: nothing to do */
      return OK;
  
    if (!deleting)                    /* op_delete() already set y_current */
      get_yank_register(oap->regname, TRUE);
  
    curr = y_current;
    /* append to existing contents */
    if (y_append && y_current->y_array != NULL)
      y_current = &newreg;
    else
      free_yank_all();                /* free previously yanked lines */
  
    /*
     * If the cursor was in column 1 before and after the movement, and the
     * operator is not inclusive, the yank is always linewise.
     */
    if (       oap->motion_type == MCHAR
               && oap->start.col == 0
               && !oap->inclusive
               && (!oap->is_VIsual || *p_sel == 'o')
               && !oap->block_mode
               && oap->end.col == 0
               && yanklines > 1) {
      yanktype = MLINE;
      --yankendlnum;
      --yanklines;
    }
  
    y_current->y_size = yanklines;
    y_current->y_type = yanktype;     /* set the yank register type */
    y_current->y_width = 0;
    y_current->y_array = xcalloc(yanklines, sizeof(char_u *));
  
    y_idx = 0;
    lnum = oap->start.lnum;
  
    if (oap->block_mode) {
      /* Visual block mode */
      y_current->y_type = MBLOCK;             /* set the yank register type */
      y_current->y_width = oap->end_vcol - oap->start_vcol;
  
      if (curwin->w_curswant == MAXCOL && y_current->y_width > 0)
        y_current->y_width--;
    }
  
    for (; lnum <= yankendlnum; lnum++, y_idx++) {
      switch (y_current->y_type) {
      case MBLOCK:
        block_prep(oap, &bd, lnum, FALSE);
        yank_copy_line(&bd, y_idx);
        break;
  
      case MLINE:
        y_current->y_array[y_idx] = vim_strsave(ml_get(lnum));
        break;
  
      case MCHAR:
      {
        colnr_T startcol = 0, endcol = MAXCOL;
        int is_oneChar = FALSE;
        colnr_T cs, ce;
        p = ml_get(lnum);
        bd.startspaces = 0;
        bd.endspaces = 0;
  
        if (lnum == oap->start.lnum) {
          startcol = oap->start.col;
          if (virtual_op) {
            getvcol(curwin, &oap->start, &cs, NULL, &ce);
            if (ce != cs && oap->start.coladd > 0) {
              /* Part of a tab selected -- but don't
               * double-count it. */
              bd.startspaces = (ce - cs + 1)
                               - oap->start.coladd;
              startcol++;
            }
          }
        }
  
        if (lnum == oap->end.lnum) {
          endcol = oap->end.col;
          if (virtual_op) {
            getvcol(curwin, &oap->end, &cs, NULL, &ce);
            if (p[endcol] == NUL || (cs + oap->end.coladd < ce
                                     /* Don't add space for double-wide
                                      * char; endcol will be on last byte
                                      * of multi-byte char. */
                                     && (*mb_head_off)(p, p + endcol) == 0
                                     )) {
              if (oap->start.lnum == oap->end.lnum
                  && oap->start.col == oap->end.col) {
                /* Special case: inside a single char */
                is_oneChar = TRUE;
                bd.startspaces = oap->end.coladd
                                 - oap->start.coladd + oap->inclusive;
                endcol = startcol;
              } else {
                bd.endspaces = oap->end.coladd
                               + oap->inclusive;
                endcol -= oap->inclusive;
              }
            }
          }
        }
        if (endcol == MAXCOL)
          endcol = (colnr_T)STRLEN(p);
        if (startcol > endcol
            || is_oneChar
            )
          bd.textlen = 0;
        else {
          bd.textlen = endcol - startcol + oap->inclusive;
        }
        bd.textstart = p + startcol;
        yank_copy_line(&bd, y_idx);
        break;
      }
        /* NOTREACHED */
      }
    }
  
    if (curr != y_current) {      /* append the new block to the old block */
      new_ptr = xmalloc(sizeof(char_u *) * (curr->y_size + y_current->y_size));
      for (j = 0; j < curr->y_size; ++j)
        new_ptr[j] = curr->y_array[j];
      free(curr->y_array);
      curr->y_array = new_ptr;
  
      if (yanktype == MLINE)      /* MLINE overrides MCHAR and MBLOCK */
        curr->y_type = MLINE;
  
      /* Concatenate the last line of the old block with the first line of
       * the new block, unless being Vi compatible. */
      if (curr->y_type == MCHAR && vim_strchr(p_cpo, CPO_REGAPPEND) == NULL) {
        pnew = xmalloc(STRLEN(curr->y_array[curr->y_size - 1])
                       + STRLEN(y_current->y_array[0]) + 1);
        STRCPY(pnew, curr->y_array[--j]);
        STRCAT(pnew, y_current->y_array[0]);
        free(curr->y_array[j]);
        free(y_current->y_array[0]);
        curr->y_array[j++] = pnew;
        y_idx = 1;
      } else
        y_idx = 0;
      while (y_idx < y_current->y_size)
        curr->y_array[j++] = y_current->y_array[y_idx++];
      curr->y_size = j;
      free(y_current->y_array);
      y_current = curr;
    }
    if (curwin->w_p_rnu) {
      redraw_later(SOME_VALID);  // cursor moved to start
    }
    if (mess) {                   /* Display message about yank? */
      if (yanktype == MCHAR
          && !oap->block_mode
          && yanklines == 1)
        yanklines = 0;
      /* Some versions of Vi use ">=" here, some don't...  */
      if (yanklines > p_report) {
        /* redisplay now, so message is not deleted */
        update_topline_redraw();
        if (yanklines == 1) {
          if (oap->block_mode)
            MSG(_("block of 1 line yanked"));
          else
            MSG(_("1 line yanked"));
        } else if (oap->block_mode)
          smsg((char_u *)_("block of %" PRId64 " lines yanked"),
               (int64_t)yanklines);
        else
          smsg((char_u *)_("%" PRId64 " lines yanked"), (int64_t)yanklines);
      }
    }
  
    /*
     * Set "'[" and "']" marks.
     */
    curbuf->b_op_start = oap->start;
    curbuf->b_op_end = oap->end;
    if (yanktype == MLINE
        && !oap->block_mode
        ) {
      curbuf->b_op_start.col = 0;
      curbuf->b_op_end.col = MAXCOL;
    }
  
    set_clipboard(oap->regname);
  
    return OK;
  }
  
  static void yank_copy_line(struct block_def *bd, long y_idx)
  {
    char_u *pnew = xmallocz(bd->startspaces + bd->endspaces + bd->textlen);
  
    y_current->y_array[y_idx] = pnew;
    memset(pnew, ' ', (size_t)bd->startspaces);
    pnew += bd->startspaces;
    memmove(pnew, bd->textstart, (size_t)bd->textlen);
    pnew += bd->textlen;
    memset(pnew, ' ', (size_t)bd->endspaces);
    pnew += bd->endspaces;
    *pnew = NUL;
  }
  
  
  /*
   * Put contents of register "regname" into the text.
   * Caller must check "regname" to be valid!
   * "flags": PUT_FIXINDENT	make indent look nice
   *	    PUT_CURSEND		leave cursor after end of new text
   *	    PUT_LINE		force linewise put (":put")
   */
  void 
  do_put (
      int regname,
      int dir,                        /* BACKWARD for 'P', FORWARD for 'p' */
      long count,
      int flags
  )
  {
    char_u      *ptr;
    char_u      *newp, *oldp;
    int yanklen;
    int totlen = 0;                       /* init for gcc */
    linenr_T lnum;
    colnr_T col;
    long i;                               /* index in y_array[] */
    int y_type;
    long y_size;
    int oldlen;
    long y_width = 0;
    colnr_T vcol;
    int delcount;
    int incr = 0;
    long j;
    struct block_def bd;
    char_u      **y_array = NULL;
    long nr_lines = 0;
    pos_T new_cursor;
    int indent;
    int orig_indent = 0;                  /* init for gcc */
    int indent_diff = 0;                  /* init for gcc */
    int first_indent = TRUE;
    int lendiff = 0;
    pos_T old_pos;
    char_u      *insert_string = NULL;
    int allocated = FALSE;
    long cnt;
  
    get_clipboard(regname);
  
    if (flags & PUT_FIXINDENT)
      orig_indent = get_indent();
  
    curbuf->b_op_start = curwin->w_cursor;        /* default for '[ mark */
    curbuf->b_op_end = curwin->w_cursor;          /* default for '] mark */
  
    /*
     * Using inserted text works differently, because the register includes
     * special characters (newlines, etc.).
     */
    if (regname == '.') {
      (void)stuff_inserted((dir == FORWARD ? (count == -1 ? 'o' : 'a') :
                            (count == -1 ? 'O' : 'i')), count, FALSE);
      /* Putting the text is done later, so can't really move the cursor to
       * the next character.  Use "l" to simulate it. */
      if ((flags & PUT_CURSEND) && gchar_cursor() != NUL)
        stuffcharReadbuff('l');
      return;
    }
  
    /*
     * For special registers '%' (file name), '#' (alternate file name) and
     * ':' (last command line), etc. we have to create a fake yank register.
     */
    if (get_spec_reg(regname, &insert_string, &allocated, TRUE)) {
      if (insert_string == NULL)
        return;
    }
  
    /* Autocommands may be executed when saving lines for undo, which may make
     * y_array invalid.  Start undo now to avoid that. */
    if (u_save(curwin->w_cursor.lnum, curwin->w_cursor.lnum + 1) == FAIL) {
      ELOG(_("Failed to save undo information"));
      return;
    }
  
    if (insert_string != NULL) {
      y_type = MCHAR;
      if (regname == '=') {
        /* For the = register we need to split the string at NL
         * characters.
         * Loop twice: count the number of lines and save them. */
        for (;; ) {
          y_size = 0;
          ptr = insert_string;
          while (ptr != NULL) {
            if (y_array != NULL)
              y_array[y_size] = ptr;
            ++y_size;
            ptr = vim_strchr(ptr, '\n');
            if (ptr != NULL) {
              if (y_array != NULL)
                *ptr = NUL;
              ++ptr;
              /* A trailing '\n' makes the register linewise. */
              if (*ptr == NUL) {
                y_type = MLINE;
                break;
              }
            }
          }
          if (y_array != NULL)
            break;
          y_array = (char_u **)xmalloc(y_size * sizeof(char_u *));
        }
      } else {
        y_size = 1;               /* use fake one-line yank register */
        y_array = &insert_string;
      }
    } else {
      get_yank_register(regname, FALSE);
  
      y_type = y_current->y_type;
      y_width = y_current->y_width;
      y_size = y_current->y_size;
      y_array = y_current->y_array;
    }
  
    if (y_type == MLINE) {
      if (flags & PUT_LINE_SPLIT) {
        /* "p" or "P" in Visual mode: split the lines to put the text in
         * between. */
        if (u_save_cursor() == FAIL)
          goto end;
        ptr = vim_strsave(get_cursor_pos_ptr());
        ml_append(curwin->w_cursor.lnum, ptr, (colnr_T)0, FALSE);
        free(ptr);
  
        ptr = vim_strnsave(get_cursor_line_ptr(), curwin->w_cursor.col);
        ml_replace(curwin->w_cursor.lnum, ptr, FALSE);
        ++nr_lines;
        dir = FORWARD;
      }
      if (flags & PUT_LINE_FORWARD) {
        /* Must be "p" for a Visual block, put lines below the block. */
        curwin->w_cursor = curbuf->b_visual.vi_end;
        dir = FORWARD;
      }
      curbuf->b_op_start = curwin->w_cursor;      /* default for '[ mark */
      curbuf->b_op_end = curwin->w_cursor;        /* default for '] mark */
    }
  
    if (flags & PUT_LINE)         /* :put command or "p" in Visual line mode. */
      y_type = MLINE;
  
    if (y_size == 0 || y_array == NULL) {
      EMSG2(_("E353: Nothing in register %s"),
          regname == 0 ? (char_u *)"\"" : transchar(regname));
      goto end;
    }
  
    if (y_type == MBLOCK) {
      lnum = curwin->w_cursor.lnum + y_size + 1;
      if (lnum > curbuf->b_ml.ml_line_count)
        lnum = curbuf->b_ml.ml_line_count + 1;
      if (u_save(curwin->w_cursor.lnum - 1, lnum) == FAIL)
        goto end;
    } else if (y_type == MLINE) {
      lnum = curwin->w_cursor.lnum;
      /* Correct line number for closed fold.  Don't move the cursor yet,
       * u_save() uses it. */
      if (dir == BACKWARD)
        (void)hasFolding(lnum, &lnum, NULL);
      else
        (void)hasFolding(lnum, NULL, &lnum);
      if (dir == FORWARD)
        ++lnum;
      /* In an empty buffer the empty line is going to be replaced, include
       * it in the saved lines. */
      if ((bufempty() ? u_save(0, 2) : u_save(lnum - 1, lnum)) == FAIL)
        goto end;
      if (dir == FORWARD)
        curwin->w_cursor.lnum = lnum - 1;
      else
        curwin->w_cursor.lnum = lnum;
      curbuf->b_op_start = curwin->w_cursor;      /* for mark_adjust() */
    } else if (u_save_cursor() == FAIL)
      goto end;
  
    yanklen = (int)STRLEN(y_array[0]);
  
    if (ve_flags == VE_ALL && y_type == MCHAR) {
      if (gchar_cursor() == TAB) {
        /* Don't need to insert spaces when "p" on the last position of a
         * tab or "P" on the first position. */
        if (dir == FORWARD
            ? (int)curwin->w_cursor.coladd < curbuf->b_p_ts - 1
            : curwin->w_cursor.coladd > 0)
          coladvance_force(getviscol());
        else
          curwin->w_cursor.coladd = 0;
      } else if (curwin->w_cursor.coladd > 0 || gchar_cursor() == NUL)
        coladvance_force(getviscol() + (dir == FORWARD));
    }
  
    lnum = curwin->w_cursor.lnum;
    col = curwin->w_cursor.col;
  
    /*
     * Block mode
     */
    if (y_type == MBLOCK) {
      char c = gchar_cursor();
      colnr_T endcol2 = 0;
  
      if (dir == FORWARD && c != NUL) {
        if (ve_flags == VE_ALL)
          getvcol(curwin, &curwin->w_cursor, &col, NULL, &endcol2);
        else
          getvcol(curwin, &curwin->w_cursor, NULL, NULL, &col);
  
        if (has_mbyte)
          /* move to start of next multi-byte character */
          curwin->w_cursor.col += (*mb_ptr2len)(get_cursor_pos_ptr());
        else if (c != TAB || ve_flags != VE_ALL)
          ++curwin->w_cursor.col;
        ++col;
      } else
        getvcol(curwin, &curwin->w_cursor, &col, NULL, &endcol2);
  
      col += curwin->w_cursor.coladd;
      if (ve_flags == VE_ALL
          && (curwin->w_cursor.coladd > 0
              || endcol2 == curwin->w_cursor.col)) {
        if (dir == FORWARD && c == NUL)
          ++col;
        if (dir != FORWARD && c != NUL)
          ++curwin->w_cursor.col;
        if (c == TAB) {
          if (dir == BACKWARD && curwin->w_cursor.col)
            curwin->w_cursor.col--;
          if (dir == FORWARD && col - 1 == endcol2)
            curwin->w_cursor.col++;
        }
      }
      curwin->w_cursor.coladd = 0;
      bd.textcol = 0;
      for (i = 0; i < y_size; ++i) {
        int spaces;
        char shortline;
  
        bd.startspaces = 0;
        bd.endspaces = 0;
        vcol = 0;
        delcount = 0;
  
        /* add a new line */
        if (curwin->w_cursor.lnum > curbuf->b_ml.ml_line_count) {
          if (ml_append(curbuf->b_ml.ml_line_count, (char_u *)"",
                  (colnr_T)1, FALSE) == FAIL)
            break;
          ++nr_lines;
        }
        /* get the old line and advance to the position to insert at */
        oldp = get_cursor_line_ptr();
        oldlen = (int)STRLEN(oldp);
        for (ptr = oldp; vcol < col && *ptr; ) {
          /* Count a tab for what it's worth (if list mode not on) */
          incr = lbr_chartabsize_adv(oldp, &ptr, (colnr_T)vcol);
          vcol += incr;
        }
        bd.textcol = (colnr_T)(ptr - oldp);
  
        shortline = (vcol < col) || (vcol == col && !*ptr);
  
        if (vcol < col)       /* line too short, padd with spaces */
          bd.startspaces = col - vcol;
        else if (vcol > col) {
          bd.endspaces = vcol - col;
          bd.startspaces = incr - bd.endspaces;
          --bd.textcol;
          delcount = 1;
          if (has_mbyte)
            bd.textcol -= (*mb_head_off)(oldp, oldp + bd.textcol);
          if (oldp[bd.textcol] != TAB) {
            /* Only a Tab can be split into spaces.  Other
             * characters will have to be moved to after the
             * block, causing misalignment. */
            delcount = 0;
            bd.endspaces = 0;
          }
        }
  
        yanklen = (int)STRLEN(y_array[i]);
  
        /* calculate number of spaces required to fill right side of block*/
        spaces = y_width + 1;
        for (j = 0; j < yanklen; j++)
          spaces -= lbr_chartabsize(NULL, &y_array[i][j], 0);
        if (spaces < 0)
          spaces = 0;
  
        /* insert the new text */
        totlen = count * (yanklen + spaces) + bd.startspaces + bd.endspaces;
        newp = (char_u *) xmalloc((size_t)(totlen + oldlen + 1));
        /* copy part up to cursor to new line */
        ptr = newp;
        memmove(ptr, oldp, (size_t)bd.textcol);
        ptr += bd.textcol;
        /* may insert some spaces before the new text */
        memset(ptr, ' ', (size_t)bd.startspaces);
        ptr += bd.startspaces;
        /* insert the new text */
        for (j = 0; j < count; ++j) {
          memmove(ptr, y_array[i], (size_t)yanklen);
          ptr += yanklen;
  
          /* insert block's trailing spaces only if there's text behind */
          if ((j < count - 1 || !shortline) && spaces) {
            memset(ptr, ' ', (size_t)spaces);
            ptr += spaces;
          }
        }
        /* may insert some spaces after the new text */
        memset(ptr, ' ', (size_t)bd.endspaces);
        ptr += bd.endspaces;
        /* move the text after the cursor to the end of the line. */
        memmove(ptr, oldp + bd.textcol + delcount,
            (size_t)(oldlen - bd.textcol - delcount + 1));
        ml_replace(curwin->w_cursor.lnum, newp, FALSE);
  
        ++curwin->w_cursor.lnum;
        if (i == 0)
          curwin->w_cursor.col += bd.startspaces;
      }
  
      changed_lines(lnum, 0, curwin->w_cursor.lnum, nr_lines);
  
      /* Set '[ mark. */
      curbuf->b_op_start = curwin->w_cursor;
      curbuf->b_op_start.lnum = lnum;
  
      /* adjust '] mark */
      curbuf->b_op_end.lnum = curwin->w_cursor.lnum - 1;
      curbuf->b_op_end.col = bd.textcol + totlen - 1;
      curbuf->b_op_end.coladd = 0;
      if (flags & PUT_CURSEND) {
        colnr_T len;
  
        curwin->w_cursor = curbuf->b_op_end;
        curwin->w_cursor.col++;
  
        /* in Insert mode we might be after the NUL, correct for that */
        len = (colnr_T)STRLEN(get_cursor_line_ptr());
        if (curwin->w_cursor.col > len)
          curwin->w_cursor.col = len;
      } else
        curwin->w_cursor.lnum = lnum;
    } else {
      /*
       * Character or Line mode
       */
      if (y_type == MCHAR) {
        /* if type is MCHAR, FORWARD is the same as BACKWARD on the next
         * char */
        if (dir == FORWARD && gchar_cursor() != NUL) {
          if (has_mbyte) {
            int bytelen = (*mb_ptr2len)(get_cursor_pos_ptr());
  
            /* put it on the next of the multi-byte character. */
            col += bytelen;
            if (yanklen) {
              curwin->w_cursor.col += bytelen;
              curbuf->b_op_end.col += bytelen;
            }
          } else {
            ++col;
            if (yanklen) {
              ++curwin->w_cursor.col;
              ++curbuf->b_op_end.col;
            }
          }
        }
        curbuf->b_op_start = curwin->w_cursor;
      }
      /*
       * Line mode: BACKWARD is the same as FORWARD on the previous line
       */
      else if (dir == BACKWARD)
        --lnum;
      new_cursor = curwin->w_cursor;
  
      /*
       * simple case: insert into current line
       */
      if (y_type == MCHAR && y_size == 1) {
        do {
          totlen = count * yanklen;
          if (totlen > 0) {
            oldp = ml_get(lnum);
            newp = (char_u *) xmalloc((size_t)(STRLEN(oldp) + totlen + 1));
            memmove(newp, oldp, (size_t)col);
            ptr = newp + col;
            for (i = 0; i < count; ++i) {
              memmove(ptr, y_array[0], (size_t)yanklen);
              ptr += yanklen;
            }
            STRMOVE(ptr, oldp + col);
            ml_replace(lnum, newp, FALSE);
            /* Place cursor on last putted char. */
            if (lnum == curwin->w_cursor.lnum) {
              /* make sure curwin->w_virtcol is updated */
              changed_cline_bef_curs();
              curwin->w_cursor.col += (colnr_T)(totlen - 1);
            }
          }
          if (VIsual_active)
            lnum++;
        } while (VIsual_active && lnum <= curbuf->b_visual.vi_end.lnum);
  
        if (VIsual_active) {  /* reset lnum to the last visual line */
          lnum--;
        }
  
        curbuf->b_op_end = curwin->w_cursor;
        /* For "CTRL-O p" in Insert mode, put cursor after last char */
        if (totlen && (restart_edit != 0 || (flags & PUT_CURSEND)))
          ++curwin->w_cursor.col;
        changed_bytes(lnum, col);
      } else {
        /*
         * Insert at least one line.  When y_type is MCHAR, break the first
         * line in two.
         */
        for (cnt = 1; cnt <= count; ++cnt) {
          i = 0;
          if (y_type == MCHAR) {
            /*
             * Split the current line in two at the insert position.
             * First insert y_array[size - 1] in front of second line.
             * Then append y_array[0] to first line.
             */
            lnum = new_cursor.lnum;
            ptr = ml_get(lnum) + col;
            totlen = (int)STRLEN(y_array[y_size - 1]);
            newp = (char_u *) xmalloc((size_t)(STRLEN(ptr) + totlen + 1));
            STRCPY(newp, y_array[y_size - 1]);
            STRCAT(newp, ptr);
            /* insert second line */
            ml_append(lnum, newp, (colnr_T)0, FALSE);
            free(newp);
  
            oldp = ml_get(lnum);
            newp = (char_u *) xmalloc((size_t)(col + yanklen + 1));
            /* copy first part of line */
            memmove(newp, oldp, (size_t)col);
            /* append to first line */
            memmove(newp + col, y_array[0], (size_t)(yanklen + 1));
            ml_replace(lnum, newp, FALSE);
  
            curwin->w_cursor.lnum = lnum;
            i = 1;
          }
  
          for (; i < y_size; ++i) {
            if ((y_type != MCHAR || i < y_size - 1)
                && ml_append(lnum, y_array[i], (colnr_T)0, FALSE)
                == FAIL)
              goto error;
            lnum++;
            ++nr_lines;
            if (flags & PUT_FIXINDENT) {
              old_pos = curwin->w_cursor;
              curwin->w_cursor.lnum = lnum;
              ptr = ml_get(lnum);
              if (cnt == count && i == y_size - 1)
                lendiff = (int)STRLEN(ptr);
              if (*ptr == '#' && preprocs_left())
                indent = 0;                   /* Leave # lines at start */
              else if (*ptr == NUL)
                indent = 0;                   /* Ignore empty lines */
              else if (first_indent) {
                indent_diff = orig_indent - get_indent();
                indent = orig_indent;
                first_indent = FALSE;
              } else if ((indent = get_indent() + indent_diff) < 0)
                indent = 0;
              (void)set_indent(indent, 0);
              curwin->w_cursor = old_pos;
              /* remember how many chars were removed */
              if (cnt == count && i == y_size - 1)
                lendiff -= (int)STRLEN(ml_get(lnum));
            }
          }
        }
  
  error:
        /* Adjust marks. */
        if (y_type == MLINE) {
          curbuf->b_op_start.col = 0;
          if (dir == FORWARD)
            curbuf->b_op_start.lnum++;
        }
        mark_adjust(curbuf->b_op_start.lnum + (y_type == MCHAR),
            (linenr_T)MAXLNUM, nr_lines, 0L);
  
        /* note changed text for displaying and folding */
        if (y_type == MCHAR)
          changed_lines(curwin->w_cursor.lnum, col,
              curwin->w_cursor.lnum + 1, nr_lines);
        else
          changed_lines(curbuf->b_op_start.lnum, 0,
              curbuf->b_op_start.lnum, nr_lines);
  
        /* put '] mark at last inserted character */
        curbuf->b_op_end.lnum = lnum;
        /* correct length for change in indent */
        col = (colnr_T)STRLEN(y_array[y_size - 1]) - lendiff;
        if (col > 1)
          curbuf->b_op_end.col = col - 1;
        else
          curbuf->b_op_end.col = 0;
  
        if (flags & PUT_CURSLINE) {
          /* ":put": put cursor on last inserted line */
          curwin->w_cursor.lnum = lnum;
          beginline(BL_WHITE | BL_FIX);
        } else if (flags & PUT_CURSEND) {
          /* put cursor after inserted text */
          if (y_type == MLINE) {
            if (lnum >= curbuf->b_ml.ml_line_count)
              curwin->w_cursor.lnum = curbuf->b_ml.ml_line_count;
            else
              curwin->w_cursor.lnum = lnum + 1;
            curwin->w_cursor.col = 0;
          } else {
            curwin->w_cursor.lnum = lnum;
            curwin->w_cursor.col = col;
          }
        } else if (y_type == MLINE) {
          /* put cursor on first non-blank in first inserted line */
          curwin->w_cursor.col = 0;
          if (dir == FORWARD)
            ++curwin->w_cursor.lnum;
          beginline(BL_WHITE | BL_FIX);
        } else            /* put cursor on first inserted character */
          curwin->w_cursor = new_cursor;
      }
    }
  
    msgmore(nr_lines);
    curwin->w_set_curswant = TRUE;
  
  end:
    if (allocated)
      free(insert_string);
    if (regname == '=')
      free(y_array);
  
    VIsual_active = FALSE;
  
    /* If the cursor is past the end of the line put it at the end. */
    adjust_cursor_eol();
  }
  
  /*
   * When the cursor is on the NUL past the end of the line and it should not be
   * there move it left.
   */
  void adjust_cursor_eol(void)
  {
    if (curwin->w_cursor.col > 0
        && gchar_cursor() == NUL
        && (ve_flags & VE_ONEMORE) == 0
        && !(restart_edit || (State & INSERT))) {
      /* Put the cursor on the last character in the line. */
      dec_cursor();
  
      if (ve_flags == VE_ALL) {
        colnr_T scol, ecol;
  
        /* Coladd is set to the width of the last character. */
        getvcol(curwin, &curwin->w_cursor, &scol, NULL, &ecol);
        curwin->w_cursor.coladd = ecol - scol + 1;
      }
    }
  }
  
  /*
   * Return TRUE if lines starting with '#' should be left aligned.
   */
  int preprocs_left(void)
  {
    return
      (curbuf->b_p_si && !curbuf->b_p_cin) ||
      (curbuf->b_p_cin && in_cinkeys('#', ' ', TRUE)
       && curbuf->b_ind_hash_comment == 0)
    ;
  }
  
  /* Return the character name of the register with the given number */
  int get_register_name(int num)
  {
    if (num == -1)
      return '"';
    else if (num < 10)
      return num + '0';
    else if (num == DELETION_REGISTER)
      return '-';
    else {
      return num + 'a' - 10;
    }
  }
  
  /*
   * ":dis" and ":registers": Display the contents of the yank registers.
   */
  void ex_display(exarg_T *eap)
  {
    int i, n;
    long j;
    char_u              *p;
    struct yankreg      *yb;
    int name;
    int attr;
    char_u              *arg = eap->arg;
    int clen;
  
    if (arg != NULL && *arg == NUL)
      arg = NULL;
    attr = hl_attr(HLF_8);
  
    /* Highlight title */
    MSG_PUTS_TITLE(_("\n--- Registers ---"));
    for (i = -1; i < NUM_REGISTERS && !got_int; ++i) {
      name = get_register_name(i);
      if (arg != NULL && vim_strchr(arg, name) == NULL
  #ifdef ONE_CLIPBOARD
          /* Star register and plus register contain the same thing. */
          && (name != '*' || vim_strchr(arg, '+') == NULL)
  #endif
          )
        continue;             /* did not ask for this register */
  
      get_clipboard(name);
  
      if (i == -1) {
        if (y_previous != NULL)
          yb = y_previous;
        else
          yb = &(y_regs[0]);
      } else
        yb = &(y_regs[i]);
  
      if (name == vim_tolower(redir_reg)
          || (redir_reg == '"' && yb == y_previous))
        continue;             /* do not list register being written to, the
                               * pointer can be freed */
  
      if (yb->y_array != NULL) {
        msg_putchar('\n');
        msg_putchar('"');
        msg_putchar(name);
        MSG_PUTS("   ");
  
        n = (int)Columns - 6;
        for (j = 0; j < yb->y_size && n > 1; ++j) {
          if (j) {
            MSG_PUTS_ATTR("^J", attr);
            n -= 2;
          }
          for (p = yb->y_array[j]; *p && (n -= ptr2cells(p)) >= 0; ++p) {
            clen = (*mb_ptr2len)(p);
            msg_outtrans_len(p, clen);
            p += clen - 1;
          }
        }
        if (n > 1 && yb->y_type == MLINE)
          MSG_PUTS_ATTR("^J", attr);
        out_flush();                          /* show one line at a time */
      }
      os_breakcheck();
    }
  
    /*
     * display last inserted text
     */
    if ((p = get_last_insert()) != NULL
        && (arg == NULL || vim_strchr(arg, '.') != NULL) && !got_int) {
      MSG_PUTS("\n\".   ");
      dis_msg(p, TRUE);
    }
  
    /*
     * display last command line
     */
    if (last_cmdline != NULL && (arg == NULL || vim_strchr(arg, ':') != NULL)
        && !got_int) {
      MSG_PUTS("\n\":   ");
      dis_msg(last_cmdline, FALSE);
    }
  
    /*
     * display current file name
     */
    if (curbuf->b_fname != NULL
        && (arg == NULL || vim_strchr(arg, '%') != NULL) && !got_int) {
      MSG_PUTS("\n\"%   ");
      dis_msg(curbuf->b_fname, FALSE);
    }
  
    /*
     * display alternate file name
     */
    if ((arg == NULL || vim_strchr(arg, '%') != NULL) && !got_int) {
      char_u      *fname;
      linenr_T dummy;
  
      if (buflist_name_nr(0, &fname, &dummy) != FAIL) {
        MSG_PUTS("\n\"#   ");
        dis_msg(fname, FALSE);
      }
    }
  
    /*
     * display last search pattern
     */
    if (last_search_pat() != NULL
        && (arg == NULL || vim_strchr(arg, '/') != NULL) && !got_int) {
      MSG_PUTS("\n\"/   ");
      dis_msg(last_search_pat(), FALSE);
    }
  
    /*
     * display last used expression
     */
    if (expr_line != NULL && (arg == NULL || vim_strchr(arg, '=') != NULL)
        && !got_int) {
      MSG_PUTS("\n\"=   ");
      dis_msg(expr_line, FALSE);
    }
  }
  
  /*
   * display a string for do_dis()
   * truncate at end of screen line
   */
  static void 
  dis_msg (
      char_u *p,
      int skip_esc                       /* if TRUE, ignore trailing ESC */
  )
  {
    int n;
    int l;
  
    n = (int)Columns - 6;
    while (*p != NUL
           && !(*p == ESC && skip_esc && *(p + 1) == NUL)
           && (n -= ptr2cells(p)) >= 0) {
      if (has_mbyte && (l = (*mb_ptr2len)(p)) > 1) {
        msg_outtrans_len(p, l);
        p += l;
      } else
        msg_outtrans_len(p++, 1);
    }
    os_breakcheck();
  }
  
  /*
   * If "process" is TRUE and the line begins with a comment leader (possibly
   * after some white space), return a pointer to the text after it. Put a boolean
   * value indicating whether the line ends with an unclosed comment in
   * "is_comment".
   * line - line to be processed,
   * process - if FALSE, will only check whether the line ends with an unclosed
   *	     comment,
   * include_space - whether to also skip space following the comment leader,
   * is_comment - will indicate whether the current line ends with an unclosed
   *		comment.
   */
  static char_u *skip_comment(char_u *line, int process, int include_space, int *is_comment)
  {
    char_u *comment_flags = NULL;
    int lead_len;
    int leader_offset = get_last_leader_offset(line, &comment_flags);
  
    *is_comment = FALSE;
    if (leader_offset != -1) {
      /* Let's check whether the line ends with an unclosed comment.
       * If the last comment leader has COM_END in flags, there's no comment.
       */
      while (*comment_flags) {
        if (*comment_flags == COM_END
            || *comment_flags == ':')
          break;
        ++comment_flags;
      }
      if (*comment_flags != COM_END)
        *is_comment = TRUE;
    }
  
    if (process == FALSE)
      return line;
  
    lead_len = get_leader_len(line, &comment_flags, FALSE, include_space);
  
    if (lead_len == 0)
      return line;
  
    /* Find:
     * - COM_END,
     * - colon,
     * whichever comes first.
     */
    while (*comment_flags) {
      if (*comment_flags == COM_END
          || *comment_flags == ':') {
        break;
      }
      ++comment_flags;
    }
  
    /* If we found a colon, it means that we are not processing a line
     * starting with a closing part of a three-part comment. That's good,
     * because we don't want to remove those as this would be annoying.
     */
    if (*comment_flags == ':' || *comment_flags == NUL)
      line += lead_len;
  
    return line;
  }
  
  // Join 'count' lines (minimal 2) at cursor position.
  // When "save_undo" is TRUE save lines for undo first.
  // Set "use_formatoptions" to FALSE when e.g. processing backspace and comment
  // leaders should not be removed.
  // When setmark is true, sets the '[ and '] mark, else, the caller is expected
  // to set those marks.
  //
  // return FAIL for failure, OK otherwise
  int do_join(long count,
              int insert_space,
              int save_undo,
              int use_formatoptions,
              bool setmark)
  {
    char_u      *curr = NULL;
    char_u      *curr_start = NULL;
    char_u      *cend;
    char_u      *newp;
    char_u      *spaces;          /* number of spaces inserted before a line */
    int endcurr1 = NUL;
    int endcurr2 = NUL;
    int currsize = 0;             /* size of the current line */
    int sumsize = 0;              /* size of the long new line */
    linenr_T t;
    colnr_T col = 0;
    int ret = OK;
    int         *comments = NULL;
    int remove_comments = (use_formatoptions == TRUE)
                          && has_format_option(FO_REMOVE_COMS);
    int prev_was_comment;
  
    assert(count > 1);
    if (save_undo && u_save((linenr_T)(curwin->w_cursor.lnum - 1),
            (linenr_T)(curwin->w_cursor.lnum + count)) == FAIL)
      return FAIL;
  
    /* Allocate an array to store the number of spaces inserted before each
     * line.  We will use it to pre-compute the length of the new line and the
     * proper placement of each original line in the new one. */
    spaces = xcalloc(count, 1);
    if (remove_comments) {
      comments = xcalloc(count, sizeof(*comments));
    }
  
    /*
     * Don't move anything, just compute the final line length
     * and setup the array of space strings lengths
     */
    for (t = 0; t < count; ++t) {
      curr = curr_start = ml_get((linenr_T)(curwin->w_cursor.lnum + t));
      if (t == 0 && setmark) {
        // Set the '[ mark.
        curwin->w_buffer->b_op_start.lnum = curwin->w_cursor.lnum;
        curwin->w_buffer->b_op_start.col = (colnr_T)STRLEN(curr);
      }
      if (remove_comments) {
        /* We don't want to remove the comment leader if the
         * previous line is not a comment. */
        if (t > 0 && prev_was_comment) {
  
          char_u *new_curr = skip_comment(curr, TRUE, insert_space,
              &prev_was_comment);
          comments[t] = (int)(new_curr - curr);
          curr = new_curr;
        } else
          curr = skip_comment(curr, FALSE, insert_space,
              &prev_was_comment);
      }
  
      if (insert_space && t > 0) {
        curr = skipwhite(curr);
        if (*curr != ')' && currsize != 0 && endcurr1 != TAB
            && (!has_format_option(FO_MBYTE_JOIN)
                || (mb_ptr2char(curr) < 0x100 && endcurr1 < 0x100))
            && (!has_format_option(FO_MBYTE_JOIN2)
                || mb_ptr2char(curr) < 0x100 || endcurr1 < 0x100)
            ) {
          /* don't add a space if the line is ending in a space */
          if (endcurr1 == ' ')
            endcurr1 = endcurr2;
          else
            ++spaces[t];
          /* extra space when 'joinspaces' set and line ends in '.' */
          if (       p_js
                     && (endcurr1 == '.'
                         || (vim_strchr(p_cpo, CPO_JOINSP) == NULL
                             && (endcurr1 == '?' || endcurr1 == '!'))))
            ++spaces[t];
        }
      }
      currsize = (int)STRLEN(curr);
      sumsize += currsize + spaces[t];
      endcurr1 = endcurr2 = NUL;
      if (insert_space && currsize > 0) {
        if (has_mbyte) {
          cend = curr + currsize;
          mb_ptr_back(curr, cend);
          endcurr1 = (*mb_ptr2char)(cend);
          if (cend > curr) {
            mb_ptr_back(curr, cend);
            endcurr2 = (*mb_ptr2char)(cend);
          }
        } else {
          endcurr1 = *(curr + currsize - 1);
          if (currsize > 1)
            endcurr2 = *(curr + currsize - 2);
        }
      }
      line_breakcheck();
      if (got_int) {
        ret = FAIL;
        goto theend;
      }
    }
  
    /* store the column position before last line */
    col = sumsize - currsize - spaces[count - 1];
  
    /* allocate the space for the new line */
    newp = (char_u *) xmalloc((size_t)(sumsize + 1));
    cend = newp + sumsize;
    *cend = 0;
  
    /*
     * Move affected lines to the new long one.
     *
     * Move marks from each deleted line to the joined line, adjusting the
     * column.  This is not Vi compatible, but Vi deletes the marks, thus that
     * should not really be a problem.
     */
    for (t = count - 1;; --t) {
      cend -= currsize;
      memmove(cend, curr, (size_t)currsize);
      if (spaces[t] > 0) {
        cend -= spaces[t];
        memset(cend, ' ', (size_t)(spaces[t]));
      }
      mark_col_adjust(curwin->w_cursor.lnum + t, (colnr_T)0, (linenr_T)-t,
          (long)(cend - newp + spaces[t] - (curr - curr_start)));
      if (t == 0)
        break;
      curr = curr_start = ml_get((linenr_T)(curwin->w_cursor.lnum + t - 1));
      if (remove_comments)
        curr += comments[t - 1];
      if (insert_space && t > 1)
        curr = skipwhite(curr);
      currsize = (int)STRLEN(curr);
    }
    ml_replace(curwin->w_cursor.lnum, newp, FALSE);
  
    if (setmark) {
      // Set the '] mark.
      curwin->w_buffer->b_op_end.lnum = curwin->w_cursor.lnum;
      curwin->w_buffer->b_op_end.col = (colnr_T)STRLEN(newp);
    }
  
    /* Only report the change in the first line here, del_lines() will report
     * the deleted line. */
    changed_lines(curwin->w_cursor.lnum, currsize,
        curwin->w_cursor.lnum + 1, 0L);
  
    /*
     * Delete following lines. To do this we move the cursor there
     * briefly, and then move it back. After del_lines() the cursor may
     * have moved up (last line deleted), so the current lnum is kept in t.
     */
    t = curwin->w_cursor.lnum;
    ++curwin->w_cursor.lnum;
    del_lines(count - 1, FALSE);
    curwin->w_cursor.lnum = t;
  
    /*
     * Set the cursor column:
     * Vi compatible: use the column of the first join
     * vim:	      use the column of the last join
     */
    curwin->w_cursor.col =
      (vim_strchr(p_cpo, CPO_JOINCOL) != NULL ? currsize : col);
    check_cursor_col();
  
    curwin->w_cursor.coladd = 0;
    curwin->w_set_curswant = TRUE;
  
  theend:
    free(spaces);
    if (remove_comments)
      free(comments);
    return ret;
  }
  
  /*
   * Return TRUE if the two comment leaders given are the same.  "lnum" is
   * the first line.  White-space is ignored.  Note that the whole of
   * 'leader1' must match 'leader2_len' characters from 'leader2' -- webb
   */
  static int same_leader(linenr_T lnum, int leader1_len, char_u *leader1_flags, int leader2_len, char_u *leader2_flags)
  {
    int idx1 = 0, idx2 = 0;
    char_u  *p;
    char_u  *line1;
    char_u  *line2;
  
    if (leader1_len == 0)
      return leader2_len == 0;
  
    /*
     * If first leader has 'f' flag, the lines can be joined only if the
     * second line does not have a leader.
     * If first leader has 'e' flag, the lines can never be joined.
     * If fist leader has 's' flag, the lines can only be joined if there is
     * some text after it and the second line has the 'm' flag.
     */
    if (leader1_flags != NULL) {
      for (p = leader1_flags; *p && *p != ':'; ++p) {
        if (*p == COM_FIRST)
          return leader2_len == 0;
        if (*p == COM_END)
          return FALSE;
        if (*p == COM_START) {
          if (*(ml_get(lnum) + leader1_len) == NUL)
            return FALSE;
          if (leader2_flags == NULL || leader2_len == 0)
            return FALSE;
          for (p = leader2_flags; *p && *p != ':'; ++p)
            if (*p == COM_MIDDLE)
              return TRUE;
          return FALSE;
        }
      }
    }
  
    /*
     * Get current line and next line, compare the leaders.
     * The first line has to be saved, only one line can be locked at a time.
     */
    line1 = vim_strsave(ml_get(lnum));
    for (idx1 = 0; vim_iswhite(line1[idx1]); ++idx1)
      ;
    line2 = ml_get(lnum + 1);
    for (idx2 = 0; idx2 < leader2_len; ++idx2) {
      if (!vim_iswhite(line2[idx2])) {
        if (line1[idx1++] != line2[idx2])
          break;
      } else
        while (vim_iswhite(line1[idx1]))
          ++idx1;
    }
    free(line1);
  
    return idx2 == leader2_len && idx1 == leader1_len;
  }
  
  /*
   * Implementation of the format operator 'gq'.
   */
  void 
  op_format (
      oparg_T *oap,
      int keep_cursor                        /* keep cursor on same text char */
  )
  {
    long old_line_count = curbuf->b_ml.ml_line_count;
  
    /* Place the cursor where the "gq" or "gw" command was given, so that "u"
     * can put it back there. */
    curwin->w_cursor = oap->cursor_start;
  
    if (u_save((linenr_T)(oap->start.lnum - 1),
            (linenr_T)(oap->end.lnum + 1)) == FAIL)
      return;
    curwin->w_cursor = oap->start;
  
    if (oap->is_VIsual)
      /* When there is no change: need to remove the Visual selection */
      redraw_curbuf_later(INVERTED);
  
    /* Set '[ mark at the start of the formatted area */
    curbuf->b_op_start = oap->start;
  
    /* For "gw" remember the cursor position and put it back below (adjusted
     * for joined and split lines). */
    if (keep_cursor)
      saved_cursor = oap->cursor_start;
  
    format_lines(oap->line_count, keep_cursor);
  
    /*
     * Leave the cursor at the first non-blank of the last formatted line.
     * If the cursor was moved one line back (e.g. with "Q}") go to the next
     * line, so "." will do the next lines.
     */
    if (oap->end_adjusted && curwin->w_cursor.lnum < curbuf->b_ml.ml_line_count)
      ++curwin->w_cursor.lnum;
    beginline(BL_WHITE | BL_FIX);
    old_line_count = curbuf->b_ml.ml_line_count - old_line_count;
    msgmore(old_line_count);
  
    /* put '] mark on the end of the formatted area */
    curbuf->b_op_end = curwin->w_cursor;
  
    if (keep_cursor) {
      curwin->w_cursor = saved_cursor;
      saved_cursor.lnum = 0;
    }
  
    if (oap->is_VIsual) {
      FOR_ALL_WINDOWS_IN_TAB(wp, curtab) {
        if (wp->w_old_cursor_lnum != 0) {
          /* When lines have been inserted or deleted, adjust the end of
           * the Visual area to be redrawn. */
          if (wp->w_old_cursor_lnum > wp->w_old_visual_lnum) {
            wp->w_old_cursor_lnum += old_line_count;
          } else {
            wp->w_old_visual_lnum += old_line_count;
          }
        }
      }
    }
  }
  
  /*
   * Implementation of the format operator 'gq' for when using 'formatexpr'.
   */
  void op_formatexpr(oparg_T *oap)
  {
    if (oap->is_VIsual)
      /* When there is no change: need to remove the Visual selection */
      redraw_curbuf_later(INVERTED);
  
    if (fex_format(oap->start.lnum, oap->line_count, NUL) != 0)
      /* As documented: when 'formatexpr' returns non-zero fall back to
       * internal formatting. */
      op_format(oap, FALSE);
  }
  
  int 
  fex_format (
      linenr_T lnum,
      long count,
      int c                  /* character to be inserted */
  )
  {
    int use_sandbox = was_set_insecurely((char_u *)"formatexpr",
        OPT_LOCAL);
    int r;
  
    /*
     * Set v:lnum to the first line number and v:count to the number of lines.
     * Set v:char to the character to be inserted (can be NUL).
     */
    set_vim_var_nr(VV_LNUM, lnum);
    set_vim_var_nr(VV_COUNT, count);
    set_vim_var_char(c);
  
    /*
     * Evaluate the function.
     */
    if (use_sandbox)
      ++sandbox;
    r = eval_to_number(curbuf->b_p_fex);
    if (use_sandbox)
      --sandbox;
  
    set_vim_var_string(VV_CHAR, NULL, -1);
  
    return r;
  }
  
  /*
   * Format "line_count" lines, starting at the cursor position.
   * When "line_count" is negative, format until the end of the paragraph.
   * Lines after the cursor line are saved for undo, caller must have saved the
   * first line.
   */
  void 
  format_lines (
      linenr_T line_count,
      int avoid_fex                          /* don't use 'formatexpr' */
  )
  {
    int max_len;
    int is_not_par;                       /* current line not part of parag. */
    int next_is_not_par;                  /* next line not part of paragraph */
    int is_end_par;                       /* at end of paragraph */
    int prev_is_end_par = FALSE;          /* prev. line not part of parag. */
    int next_is_start_par = FALSE;
    int leader_len = 0;                   /* leader len of current line */
    int next_leader_len;                  /* leader len of next line */
    char_u      *leader_flags = NULL;     /* flags for leader of current line */
    char_u      *next_leader_flags;       /* flags for leader of next line */
    int do_comments;                      /* format comments */
    int do_comments_list = 0;             /* format comments with 'n' or '2' */
    int advance = TRUE;
    int second_indent = -1;               /* indent for second line (comment
                                           * aware) */
    int do_second_indent;
    int do_number_indent;
    int do_trail_white;
    int first_par_line = TRUE;
    int smd_save;
    long count;
    int need_set_indent = TRUE;           /* set indent of next paragraph */
    int force_format = FALSE;
    int old_State = State;
  
    /* length of a line to force formatting: 3 * 'tw' */
    max_len = comp_textwidth(TRUE) * 3;
  
    /* check for 'q', '2' and '1' in 'formatoptions' */
    do_comments = has_format_option(FO_Q_COMS);
    do_second_indent = has_format_option(FO_Q_SECOND);
    do_number_indent = has_format_option(FO_Q_NUMBER);
    do_trail_white = has_format_option(FO_WHITE_PAR);
  
    /*
     * Get info about the previous and current line.
     */
    if (curwin->w_cursor.lnum > 1)
      is_not_par = fmt_check_par(curwin->w_cursor.lnum - 1
          , &leader_len, &leader_flags, do_comments
          );
    else
      is_not_par = TRUE;
    next_is_not_par = fmt_check_par(curwin->w_cursor.lnum
        , &next_leader_len, &next_leader_flags, do_comments
        );
    is_end_par = (is_not_par || next_is_not_par);
    if (!is_end_par && do_trail_white)
      is_end_par = !ends_in_white(curwin->w_cursor.lnum - 1);
  
    curwin->w_cursor.lnum--;
    for (count = line_count; count != 0 && !got_int; --count) {
      /*
       * Advance to next paragraph.
       */
      if (advance) {
        curwin->w_cursor.lnum++;
        prev_is_end_par = is_end_par;
        is_not_par = next_is_not_par;
        leader_len = next_leader_len;
        leader_flags = next_leader_flags;
      }
  
      /*
       * The last line to be formatted.
       */
      if (count == 1 || curwin->w_cursor.lnum == curbuf->b_ml.ml_line_count) {
        next_is_not_par = TRUE;
        next_leader_len = 0;
        next_leader_flags = NULL;
      } else {
        next_is_not_par = fmt_check_par(curwin->w_cursor.lnum + 1
            , &next_leader_len, &next_leader_flags, do_comments
            );
        if (do_number_indent)
          next_is_start_par =
            (get_number_indent(curwin->w_cursor.lnum + 1) > 0);
      }
      advance = TRUE;
      is_end_par = (is_not_par || next_is_not_par || next_is_start_par);
      if (!is_end_par && do_trail_white)
        is_end_par = !ends_in_white(curwin->w_cursor.lnum);
  
      /*
       * Skip lines that are not in a paragraph.
       */
      if (is_not_par) {
        if (line_count < 0)
          break;
      } else {
        /*
         * For the first line of a paragraph, check indent of second line.
         * Don't do this for comments and empty lines.
         */
        if (first_par_line
            && (do_second_indent || do_number_indent)
            && prev_is_end_par
            && curwin->w_cursor.lnum < curbuf->b_ml.ml_line_count) {
          if (do_second_indent && !lineempty(curwin->w_cursor.lnum + 1)) {
            if (leader_len == 0 && next_leader_len == 0) {
              /* no comment found */
              second_indent =
                get_indent_lnum(curwin->w_cursor.lnum + 1);
            } else {
              second_indent = next_leader_len;
              do_comments_list = 1;
            }
          } else if (do_number_indent) {
            if (leader_len == 0 && next_leader_len == 0) {
              /* no comment found */
              second_indent =
                get_number_indent(curwin->w_cursor.lnum);
            } else {
              /* get_number_indent() is now "comment aware"... */
              second_indent =
                get_number_indent(curwin->w_cursor.lnum);
              do_comments_list = 1;
            }
          }
        }
  
        /*
         * When the comment leader changes, it's the end of the paragraph.
         */
        if (curwin->w_cursor.lnum >= curbuf->b_ml.ml_line_count
            || !same_leader(curwin->w_cursor.lnum,
                leader_len, leader_flags,
                next_leader_len, next_leader_flags)
            )
          is_end_par = TRUE;
  
        /*
         * If we have got to the end of a paragraph, or the line is
         * getting long, format it.
         */
        if (is_end_par || force_format) {
          if (need_set_indent)
            /* replace indent in first line with minimal number of
             * tabs and spaces, according to current options */
            (void)set_indent(get_indent(), SIN_CHANGED);
  
          /* put cursor on last non-space */
          State = NORMAL;         /* don't go past end-of-line */
          coladvance((colnr_T)MAXCOL);
          while (curwin->w_cursor.col && vim_isspace(gchar_cursor()))
            dec_cursor();
  
          /* do the formatting, without 'showmode' */
          State = INSERT;         /* for open_line() */
          smd_save = p_smd;
          p_smd = FALSE;
          insertchar(NUL, INSCHAR_FORMAT
              + (do_comments ? INSCHAR_DO_COM : 0)
              + (do_comments && do_comments_list
                 ? INSCHAR_COM_LIST : 0)
              + (avoid_fex ? INSCHAR_NO_FEX : 0), second_indent);
          State = old_State;
          p_smd = smd_save;
          second_indent = -1;
          /* at end of par.: need to set indent of next par. */
          need_set_indent = is_end_par;
          if (is_end_par) {
            /* When called with a negative line count, break at the
             * end of the paragraph. */
            if (line_count < 0)
              break;
            first_par_line = TRUE;
          }
          force_format = FALSE;
        }
  
        /*
         * When still in same paragraph, join the lines together.  But
         * first delete the leader from the second line.
         */
        if (!is_end_par) {
          advance = FALSE;
          curwin->w_cursor.lnum++;
          curwin->w_cursor.col = 0;
          if (line_count < 0 && u_save_cursor() == FAIL)
            break;
          if (next_leader_len > 0) {
            (void)del_bytes((long)next_leader_len, FALSE, FALSE);
            mark_col_adjust(curwin->w_cursor.lnum, (colnr_T)0, 0L,
                (long)-next_leader_len);
          } else if (second_indent > 0) {  /* the "leader" for FO_Q_SECOND */
            char_u *p = get_cursor_line_ptr();
            int indent = (int)(skipwhite(p) - p);
  
            if (indent > 0) {
              (void)del_bytes(indent, FALSE, FALSE);
              mark_col_adjust(curwin->w_cursor.lnum,
                  (colnr_T)0, 0L, (long)-indent);
            }
          }
          curwin->w_cursor.lnum--;
          if (do_join(2, TRUE, FALSE, FALSE, false) == FAIL) {
            beep_flush();
            break;
          }
          first_par_line = FALSE;
          /* If the line is getting long, format it next time */
          if (STRLEN(get_cursor_line_ptr()) > (size_t)max_len)
            force_format = TRUE;
          else
            force_format = FALSE;
        }
      }
      line_breakcheck();
    }
  }
  
  /*
   * Return TRUE if line "lnum" ends in a white character.
   */
  static int ends_in_white(linenr_T lnum)
  {
    char_u      *s = ml_get(lnum);
    size_t l;
  
    if (*s == NUL)
      return FALSE;
    /* Don't use STRLEN() inside vim_iswhite(), SAS/C complains: "macro
     * invocation may call function multiple times". */
    l = STRLEN(s) - 1;
    return vim_iswhite(s[l]);
  }
  
  /*
   * Blank lines, and lines containing only the comment leader, are left
   * untouched by the formatting.  The function returns TRUE in this
   * case.  It also returns TRUE when a line starts with the end of a comment
   * ('e' in comment flags), so that this line is skipped, and not joined to the
   * previous line.  A new paragraph starts after a blank line, or when the
   * comment leader changes -- webb.
   */
  static int fmt_check_par(linenr_T lnum, int *leader_len, char_u **leader_flags, int do_comments)
  {
    char_u      *flags = NULL;        /* init for GCC */
    char_u      *ptr;
  
    ptr = ml_get(lnum);
    if (do_comments)
      *leader_len = get_leader_len(ptr, leader_flags, FALSE, TRUE);
    else
      *leader_len = 0;
  
    if (*leader_len > 0) {
      /*
       * Search for 'e' flag in comment leader flags.
       */
      flags = *leader_flags;
      while (*flags && *flags != ':' && *flags != COM_END)
        ++flags;
    }
  
    return *skipwhite(ptr + *leader_len) == NUL
           || (*leader_len > 0 && *flags == COM_END)
           || startPS(lnum, NUL, FALSE);
  }
  
  /*
   * Return TRUE when a paragraph starts in line "lnum".  Return FALSE when the
   * previous line is in the same paragraph.  Used for auto-formatting.
   */
  int paragraph_start(linenr_T lnum)
  {
    char_u *p;
    int leader_len = 0;                   /* leader len of current line */
    char_u *leader_flags = NULL;          /* flags for leader of current line */
    int next_leader_len = 0;              /* leader len of next line */
    char_u *next_leader_flags = NULL;     /* flags for leader of next line */
    int do_comments;                      /* format comments */
  
    if (lnum <= 1)
      return TRUE;                /* start of the file */
  
    p = ml_get(lnum - 1);
    if (*p == NUL)
      return TRUE;                /* after empty line */
  
    do_comments = has_format_option(FO_Q_COMS);
    if (fmt_check_par(lnum - 1
            , &leader_len, &leader_flags, do_comments
            ))
      return TRUE;                /* after non-paragraph line */
  
    if (fmt_check_par(lnum
            , &next_leader_len, &next_leader_flags, do_comments
            ))
      return TRUE;                /* "lnum" is not a paragraph line */
  
    if (has_format_option(FO_WHITE_PAR) && !ends_in_white(lnum - 1))
      return TRUE;                /* missing trailing space in previous line. */
  
    if (has_format_option(FO_Q_NUMBER) && (get_number_indent(lnum) > 0))
      return TRUE;                /* numbered item starts in "lnum". */
  
    if (!same_leader(lnum - 1, leader_len, leader_flags,
            next_leader_len, next_leader_flags))
      return TRUE;                /* change of comment leader. */
  
    return FALSE;
  }
  
  /*
   * prepare a few things for block mode yank/delete/tilde
   *
   * for delete:
   * - textlen includes the first/last char to be (partly) deleted
   * - start/endspaces is the number of columns that are taken by the
   *   first/last deleted char minus the number of columns that have to be
   *   deleted.
   * for yank and tilde:
   * - textlen includes the first/last char to be wholly yanked
   * - start/endspaces is the number of columns of the first/last yanked char
   *   that are to be yanked.
   */
  static void block_prep(oparg_T *oap, struct block_def *bdp, linenr_T lnum, int is_del)
  {
    int incr = 0;
    char_u      *pend;
    char_u      *pstart;
    char_u      *line;
    char_u      *prev_pstart;
    char_u      *prev_pend;
  
    bdp->startspaces = 0;
    bdp->endspaces = 0;
    bdp->textlen = 0;
    bdp->start_vcol = 0;
    bdp->end_vcol = 0;
    bdp->is_short = FALSE;
    bdp->is_oneChar = FALSE;
    bdp->pre_whitesp = 0;
    bdp->pre_whitesp_c = 0;
    bdp->end_char_vcols = 0;
    bdp->start_char_vcols = 0;
  
    line = ml_get(lnum);
    pstart = line;
    prev_pstart = line;
    while (bdp->start_vcol < oap->start_vcol && *pstart) {
      /* Count a tab for what it's worth (if list mode not on) */
      incr = lbr_chartabsize(line, pstart, (colnr_T)bdp->start_vcol);
      bdp->start_vcol += incr;
      if (vim_iswhite(*pstart)) {
        bdp->pre_whitesp += incr;
        bdp->pre_whitesp_c++;
      } else {
        bdp->pre_whitesp = 0;
        bdp->pre_whitesp_c = 0;
      }
      prev_pstart = pstart;
      mb_ptr_adv(pstart);
    }
    bdp->start_char_vcols = incr;
    if (bdp->start_vcol < oap->start_vcol) {      /* line too short */
      bdp->end_vcol = bdp->start_vcol;
      bdp->is_short = TRUE;
      if (!is_del || oap->op_type == OP_APPEND)
        bdp->endspaces = oap->end_vcol - oap->start_vcol + 1;
    } else {
      /* notice: this converts partly selected Multibyte characters to
       * spaces, too. */
      bdp->startspaces = bdp->start_vcol - oap->start_vcol;
      if (is_del && bdp->startspaces)
        bdp->startspaces = bdp->start_char_vcols - bdp->startspaces;
      pend = pstart;
      bdp->end_vcol = bdp->start_vcol;
      if (bdp->end_vcol > oap->end_vcol) {        /* it's all in one character */
        bdp->is_oneChar = TRUE;
        if (oap->op_type == OP_INSERT)
          bdp->endspaces = bdp->start_char_vcols - bdp->startspaces;
        else if (oap->op_type == OP_APPEND) {
          bdp->startspaces += oap->end_vcol - oap->start_vcol + 1;
          bdp->endspaces = bdp->start_char_vcols - bdp->startspaces;
        } else {
          bdp->startspaces = oap->end_vcol - oap->start_vcol + 1;
          if (is_del && oap->op_type != OP_LSHIFT) {
            /* just putting the sum of those two into
             * bdp->startspaces doesn't work for Visual replace,
             * so we have to split the tab in two */
            bdp->startspaces = bdp->start_char_vcols
                               - (bdp->start_vcol - oap->start_vcol);
            bdp->endspaces = bdp->end_vcol - oap->end_vcol - 1;
          }
        }
      } else {
        prev_pend = pend;
        while (bdp->end_vcol <= oap->end_vcol && *pend != NUL) {
          /* Count a tab for what it's worth (if list mode not on) */
          prev_pend = pend;
          // TODO: is passing prev_pend for start of the line OK?
          // prehaps it should be "line"
          incr = lbr_chartabsize_adv(prev_pend, &pend, (colnr_T)bdp->end_vcol);
          bdp->end_vcol += incr;
        }
        if (bdp->end_vcol <= oap->end_vcol
            && (!is_del
                || oap->op_type == OP_APPEND
                || oap->op_type == OP_REPLACE)) {         /* line too short */
          bdp->is_short = TRUE;
          /* Alternative: include spaces to fill up the block.
           * Disadvantage: can lead to trailing spaces when the line is
           * short where the text is put */
          /* if (!is_del || oap->op_type == OP_APPEND) */
          if (oap->op_type == OP_APPEND || virtual_op)
            bdp->endspaces = oap->end_vcol - bdp->end_vcol
                             + oap->inclusive;
          else
            bdp->endspaces = 0;           /* replace doesn't add characters */
        } else if (bdp->end_vcol > oap->end_vcol) {
          bdp->endspaces = bdp->end_vcol - oap->end_vcol - 1;
          if (!is_del && bdp->endspaces) {
            bdp->endspaces = incr - bdp->endspaces;
            if (pend != pstart)
              pend = prev_pend;
          }
        }
      }
      bdp->end_char_vcols = incr;
      if (is_del && bdp->startspaces)
        pstart = prev_pstart;
      bdp->textlen = (int)(pend - pstart);
    }
    bdp->textcol = (colnr_T) (pstart - line);
    bdp->textstart = pstart;
  }
  
  
  static void reverse_line(char_u *s)
  {
    int i, j;
    char_u c;
  
    if ((i = (int)STRLEN(s) - 1) <= 0)
      return;
  
    curwin->w_cursor.col = i - curwin->w_cursor.col;
    for (j = 0; j < i; j++, i--) {
      c = s[i]; s[i] = s[j]; s[j] = c;
    }
  }
  
  # define RLADDSUBFIX(ptr) if (curwin->w_p_rl) reverse_line(ptr);
  
  /*
   * add or subtract 'Prenum1' from a number in a line
   * 'command' is CTRL-A for add, CTRL-X for subtract
   *
   * return FAIL for failure, OK otherwise
   */
  int do_addsub(int command, linenr_T Prenum1)
  {
    int col;
    char_u      *buf1;
    char_u buf2[NUMBUFLEN];
    int hex;                      /* 'X' or 'x': hex; '0': octal */
    static int hexupper = FALSE;          /* 0xABC */
    unsigned long n, oldn;
    char_u      *ptr;
    int c;
    int length = 0;                       /* character length of the number */
    int todel;
    int dohex;
    int dooct;
    int doalp;
    int firstdigit;
    int negative;
    int subtract;
  
    dohex = (vim_strchr(curbuf->b_p_nf, 'x') != NULL);    /* "heX" */
    dooct = (vim_strchr(curbuf->b_p_nf, 'o') != NULL);    /* "Octal" */
    doalp = (vim_strchr(curbuf->b_p_nf, 'p') != NULL);    /* "alPha" */
  
    ptr = get_cursor_line_ptr();
    RLADDSUBFIX(ptr);
  
    /*
     * First check if we are on a hexadecimal number, after the "0x".
     */
    col = curwin->w_cursor.col;
    if (dohex)
      while (col > 0 && vim_isxdigit(ptr[col]))
        --col;
    if (       dohex
               && col > 0
               && (ptr[col] == 'X'
                   || ptr[col] == 'x')
               && ptr[col - 1] == '0'
               && vim_isxdigit(ptr[col + 1])) {
      /*
       * Found hexadecimal number, move to its start.
       */
      --col;
    } else {
      /*
       * Search forward and then backward to find the start of number.
       */
      col = curwin->w_cursor.col;
  
      while (ptr[col] != NUL
             && !vim_isdigit(ptr[col])
             && !(doalp && ASCII_ISALPHA(ptr[col])))
        ++col;
  
      while (col > 0
             && vim_isdigit(ptr[col - 1])
             && !(doalp && ASCII_ISALPHA(ptr[col])))
        --col;
    }
  
    /*
     * If a number was found, and saving for undo works, replace the number.
     */
    firstdigit = ptr[col];
    RLADDSUBFIX(ptr);
    if ((!VIM_ISDIGIT(firstdigit) && !(doalp && ASCII_ISALPHA(firstdigit)))
        || u_save_cursor() != OK) {
      beep_flush();
      return FAIL;
    }
  
    /* get ptr again, because u_save() may have changed it */
    ptr = get_cursor_line_ptr();
    RLADDSUBFIX(ptr);
  
    if (doalp && ASCII_ISALPHA(firstdigit)) {
      /* decrement or increment alphabetic character */
      if (command == Ctrl_X) {
        if (CharOrd(firstdigit) < Prenum1) {
          if (isupper(firstdigit))
            firstdigit = 'A';
          else
            firstdigit = 'a';
        } else
          firstdigit -= Prenum1;
      } else {
        if (26 - CharOrd(firstdigit) - 1 < Prenum1) {
          if (isupper(firstdigit))
            firstdigit = 'Z';
          else
            firstdigit = 'z';
        } else
          firstdigit += Prenum1;
      }
      curwin->w_cursor.col = col;
      (void)del_char(FALSE);
      ins_char(firstdigit);
    } else {
      negative = FALSE;
      if (col > 0 && ptr[col - 1] == '-') {           /* negative number */
        --col;
        negative = TRUE;
      }
  
      /* get the number value (unsigned) */
      vim_str2nr(ptr + col, &hex, &length, dooct, dohex, NULL, &n);
  
      /* ignore leading '-' for hex and octal numbers */
      if (hex && negative) {
        ++col;
        --length;
        negative = FALSE;
      }
  
      /* add or subtract */
      subtract = FALSE;
      if (command == Ctrl_X)
        subtract ^= TRUE;
      if (negative)
        subtract ^= TRUE;
  
      oldn = n;
      if (subtract)
        n -= (unsigned long)Prenum1;
      else
        n += (unsigned long)Prenum1;
  
      /* handle wraparound for decimal numbers */
      if (!hex) {
        if (subtract) {
          if (n > oldn) {
            n = 1 + (n ^ (unsigned long)-1);
            negative ^= TRUE;
          }
        } else { /* add */
          if (n < oldn) {
            n = (n ^ (unsigned long)-1);
            negative ^= TRUE;
          }
        }
        if (n == 0)
          negative = FALSE;
      }
  
      /*
       * Delete the old number.
       */
      curwin->w_cursor.col = col;
      todel = length;
      c = gchar_cursor();
      /*
       * Don't include the '-' in the length, only the length of the part
       * after it is kept the same.
       */
      if (c == '-')
        --length;
      while (todel-- > 0) {
        if (c < 0x100 && isalpha(c)) {
          if (isupper(c))
            hexupper = TRUE;
          else
            hexupper = FALSE;
        }
        /* del_char() will mark line needing displaying */
        (void)del_char(FALSE);
        c = gchar_cursor();
      }
  
      /*
       * Prepare the leading characters in buf1[].
       * When there are many leading zeros it could be very long.  Allocate
       * a bit too much.
       */
      buf1 = xmalloc(length + NUMBUFLEN);
      ptr = buf1;
      if (negative) {
        *ptr++ = '-';
      }
      if (hex) {
        *ptr++ = '0';
        --length;
      }
      if (hex == 'x' || hex == 'X') {
        *ptr++ = hex;
        --length;
      }
  
      /*
       * Put the number characters in buf2[].
       */
      if (hex == 0)
        sprintf((char *)buf2, "%" PRIu64, (uint64_t)n);
      else if (hex == '0')
        sprintf((char *)buf2, "%" PRIo64, (uint64_t)n);
      else if (hex && hexupper)
        sprintf((char *)buf2, "%" PRIX64, (uint64_t)n);
      else
        sprintf((char *)buf2, "%" PRIx64, (uint64_t)n);
      length -= (int)STRLEN(buf2);
  
      /*
       * Adjust number of zeros to the new number of digits, so the
       * total length of the number remains the same.
       * Don't do this when
       * the result may look like an octal number.
       */
      if (firstdigit == '0' && !(dooct && hex == 0))
        while (length-- > 0)
          *ptr++ = '0';
      *ptr = NUL;
      STRCAT(buf1, buf2);
      ins_str(buf1);              /* insert the new number */
      free(buf1);
    }
    --curwin->w_cursor.col;
    curwin->w_set_curswant = TRUE;
    ptr = ml_get_buf(curbuf, curwin->w_cursor.lnum, TRUE);
    RLADDSUBFIX(ptr);
    return OK;
  }
  
  int read_viminfo_register(vir_T *virp, int force)
  {
    int eof;
    int do_it = TRUE;
    int size;
    int limit;
    int set_prev = FALSE;
    char_u      *str;
    char_u      **array = NULL;
  
    /* We only get here (hopefully) if line[0] == '"' */
    str = virp->vir_line + 1;
  
    /* If the line starts with "" this is the y_previous register. */
    if (*str == '"') {
      set_prev = TRUE;
      str++;
    }
  
    if (!ASCII_ISALNUM(*str) && *str != '-') {
      if (viminfo_error("E577: ", _("Illegal register name"), virp->vir_line))
        return TRUE;              /* too many errors, pretend end-of-file */
      do_it = FALSE;
    }
    get_yank_register(*str++, FALSE);
    if (!force && y_current->y_array != NULL)
      do_it = FALSE;
  
    if (*str == '@') {
      /* "x@: register x used for @@ */
      if (force || execreg_lastc == NUL)
        execreg_lastc = str[-1];
    }
  
    size = 0;
    limit = 100;          /* Optimized for registers containing <= 100 lines */
    if (do_it) {
      if (set_prev)
        y_previous = y_current;
  
      free_yank_all();
      array = xmalloc(limit * sizeof(char_u *));
  
      str = skipwhite(skiptowhite(str));
      if (STRNCMP(str, "CHAR", 4) == 0)
        y_current->y_type = MCHAR;
      else if (STRNCMP(str, "BLOCK", 5) == 0)
        y_current->y_type = MBLOCK;
      else
        y_current->y_type = MLINE;
      /* get the block width; if it's missing we get a zero, which is OK */
      str = skipwhite(skiptowhite(str));
      y_current->y_width = getdigits_int(&str);
    }
  
    while (!(eof = viminfo_readline(virp))
           && (virp->vir_line[0] == TAB || virp->vir_line[0] == '<')) {
      if (do_it) {
        if (size >= limit) {
          limit *= 2;
          array = xrealloc(array, limit * sizeof(char_u *));
        }
        array[size++] = viminfo_readstring(virp, 1, TRUE);
      }
    }
  
    if (do_it) {
      if (size == 0) {
        free(array);
      } else if (size < limit) {
        y_current->y_array = xrealloc(array, size * sizeof(char_u *));
      } else {
        y_current->y_array = array;
      }
      y_current->y_size = size;
    }
    return eof;
  }
  
  void write_viminfo_registers(FILE *fp)
  {
    int i, j;
    char_u  *type;
    char_u c;
    int num_lines;
    int max_num_lines;
    int max_kbyte;
    long len;
  
    fputs(_("\n# Registers:\n"), fp);
  
    /* Get '<' value, use old '"' value if '<' is not found. */
    max_num_lines = get_viminfo_parameter('<');
    if (max_num_lines < 0)
      max_num_lines = get_viminfo_parameter('"');
    if (max_num_lines == 0)
      return;
    max_kbyte = get_viminfo_parameter('s');
    if (max_kbyte == 0)
      return;
  
    for (i = 0; i < NUM_REGISTERS; i++) {
      if (y_regs[i].y_array == NULL)
        continue;
      // Skip '*'/'+' register, we don't want them back next time
      if (i == CLIP_REGISTER)
        continue;
      /* Skip empty registers. */
      num_lines = y_regs[i].y_size;
      if (num_lines == 0
          || (num_lines == 1 && y_regs[i].y_type == MCHAR
              && *y_regs[i].y_array[0] == NUL))
        continue;
  
      if (max_kbyte > 0) {
        /* Skip register if there is more text than the maximum size. */
        len = 0;
        for (j = 0; j < num_lines; j++)
          len += (long)STRLEN(y_regs[i].y_array[j]) + 1L;
        if (len > (long)max_kbyte * 1024L)
          continue;
      }
  
      switch (y_regs[i].y_type) {
      case MLINE:
        type = (char_u *)"LINE";
        break;
      case MCHAR:
        type = (char_u *)"CHAR";
        break;
      case MBLOCK:
        type = (char_u *)"BLOCK";
        break;
      default:
        sprintf((char *)IObuff, _("E574: Unknown register type %d"),
            y_regs[i].y_type);
        emsg(IObuff);
        type = (char_u *)"LINE";
        break;
      }
      if (y_previous == &y_regs[i])
        fprintf(fp, "\"");
      c = get_register_name(i);
      fprintf(fp, "\"%c", c);
      if (c == execreg_lastc)
        fprintf(fp, "@");
      fprintf(fp, "\t%s\t%d\n", type,
          (int)y_regs[i].y_width
          );
  
      /* If max_num_lines < 0, then we save ALL the lines in the register */
      if (max_num_lines > 0 && num_lines > max_num_lines)
        num_lines = max_num_lines;
      for (j = 0; j < num_lines; j++) {
        putc('\t', fp);
        viminfo_writestring(fp, y_regs[i].y_array[j]);
      }
    }
  }
  
  
  
  
  
  /*
   * Return the type of a register.
   * Used for getregtype()
   * Returns MAUTO for error.
   */
  char_u get_reg_type(int regname, long *reglen)
  {
    switch (regname) {
    case '%':                     /* file name */
    case '#':                     /* alternate file name */
    case '=':                     /* expression */
    case ':':                     /* last command line */
    case '/':                     /* last search-pattern */
    case '.':                     /* last inserted text */
    case Ctrl_F:                  /* Filename under cursor */
    case Ctrl_P:                  /* Path under cursor, expand via "path" */
    case Ctrl_W:                  /* word under cursor */
    case Ctrl_A:                  /* WORD (mnemonic All) under cursor */
    case '_':                     /* black hole: always empty */
      return MCHAR;
    }
  
    get_clipboard(regname);
  
    if (regname != NUL && !valid_yank_reg(regname, FALSE))
      return MAUTO;
  
    get_yank_register(regname, FALSE);
  
    if (y_current->y_array != NULL) {
      if (reglen != NULL && y_current->y_type == MBLOCK)
        *reglen = y_current->y_width;
      return y_current->y_type;
    }
    return MAUTO;
  }
  
  /// When `flags` has `kGRegList` return a list with text `s`.
  /// Otherwise just return `s`.
  ///
  /// Returns a void * for use in get_reg_contents().
  static void *get_reg_wrap_one_line(char_u *s, int flags)
  {
    if (!(flags & kGRegList)) {
      return s;
    }
    list_T *list = list_alloc();
    list_append_string(list, NULL, -1);
    list->lv_first->li_tv.vval.v_string = s;
    return list;
  }
  
  /// Gets the contents of a register.
  /// @remark Used for `@r` in expressions and for `getreg()`.
  ///
  /// @param regname  The register.
  /// @param flags    see @ref GRegFlags
  ///
  /// @returns The contents of the register as an allocated string.
  /// @returns A linked list when `flags` contains @ref kGRegList.
  /// @returns NULL for error.
  void *get_reg_contents(int regname, int flags)
  {
    long i;
  
    // Don't allow using an expression register inside an expression.
    if (regname == '=') {
      if (flags & kGRegNoExpr) {
        return NULL;
      }
      if (flags & kGRegExprSrc) {
        return get_reg_wrap_one_line(get_expr_line_src(), flags);
      }
      return get_reg_wrap_one_line(get_expr_line(), flags);
    }
  
    if (regname == '@')       /* "@@" is used for unnamed register */
      regname = '"';
  
    /* check for valid regname */
    if (regname != NUL && !valid_yank_reg(regname, FALSE))
      return NULL;
  
    get_clipboard(regname);
  
    char_u *retval;
    int allocated;
    if (get_spec_reg(regname, &retval, &allocated, FALSE)) {
      if (retval == NULL)
        return NULL;
      if (allocated) {
        return get_reg_wrap_one_line(retval, flags);
      }
      return get_reg_wrap_one_line(vim_strsave(retval), flags);
    }
  
    get_yank_register(regname, FALSE);
    if (y_current->y_array == NULL)
      return NULL;
  
    if (flags & kGRegList) {
      list_T *list = list_alloc();
      for (int i = 0; i < y_current->y_size; ++i) {
        list_append_string(list, y_current->y_array[i], -1);
      }
  
      return list;
    }
  
    /*
     * Compute length of resulting string.
     */
    size_t len = 0;
    for (i = 0; i < y_current->y_size; ++i) {
      len += STRLEN(y_current->y_array[i]);
      /*
       * Insert a newline between lines and after last line if
       * y_type is MLINE.
       */
      if (y_current->y_type == MLINE || i < y_current->y_size - 1)
        ++len;
    }
  
    retval = xmalloc(len + 1);
  
    /*
     * Copy the lines of the yank register into the string.
     */
    len = 0;
    for (i = 0; i < y_current->y_size; ++i) {
      STRCPY(retval + len, y_current->y_array[i]);
      len += STRLEN(retval + len);
  
      /*
       * Insert a NL between lines and after the last line if y_type is
       * MLINE.
       */
      if (y_current->y_type == MLINE || i < y_current->y_size - 1)
        retval[len++] = '\n';
    }
    retval[len] = NUL;
  
    return retval;
  }
  
  static bool init_write_reg(int name, struct yankreg **old_y_previous,
                             struct yankreg **old_y_current, int must_append)
  {
    if (!valid_yank_reg(name, true)) {  // check for valid reg name
      emsg_invreg(name);
      return false;
    }
  
    // Don't want to change the current (unnamed) register.
    *old_y_previous = y_previous;
    *old_y_current = y_current;
  
    get_yank_register(name, true);
    if (!y_append && !must_append) {
      free_yank_all();
    }
    return true;
  }
  
  static void finish_write_reg(int name, struct yankreg  *old_y_previous,
                               struct yankreg  *old_y_current)
  {
    // Send text of clipboard register to the clipboard.
    set_clipboard(name);
  
    // ':let @" = "val"' should change the meaning of the "" register
    if (name != '"') {
      y_previous = old_y_previous;
    }
    y_current = old_y_current;
  }
  
  /// write_reg_contents - store `str` in register `name`
  ///
  /// @see write_reg_contents_ex
  void write_reg_contents(int name, const char_u *str, ssize_t len,
                          int must_append)
  {
    write_reg_contents_ex(name, str, len, must_append, MAUTO, 0L);
  }
  
  void write_reg_contents_lst(int name, char_u **strings, int maxlen,
                              int must_append, int yank_type, long block_len)
  {
    if (name == '/' || name == '=') {
      char_u  *s = strings[0];
      if (strings[0] == NULL) {
        s = (char_u *)"";
      } else if (strings[1] != NULL) {
        EMSG(_("E883: search pattern and expression register may not "
               "contain two or more lines"));
        return;
      }
      write_reg_contents_ex(name, s, -1, must_append, yank_type, block_len);
      return;
    }
  
    // black hole: nothing to do
    if (name == '_') {
      return;
    }
  
    struct yankreg  *old_y_previous, *old_y_current;
    if (!init_write_reg(name, &old_y_previous, &old_y_current, must_append)) {
      return;
    }
  
    str_to_reg(y_current, yank_type, (char_u *) strings, -1, block_len, true);
    finish_write_reg(name, old_y_previous, old_y_current);
  }
  
  /// write_reg_contents_ex - store `str` in register `name`
  ///
  /// If `str` ends in '\n' or '\r', use linewise, otherwise use
  /// characterwise.
  ///
  /// @warning when `name` is '/', `len` and `must_append` are ignored. This
  ///          means that `str` MUST be NUL-terminated.
  ///
  /// @param name The name of the register
  /// @param str The contents to write
  /// @param len If >= 0, write `len` bytes of `str`. Otherwise, write
  ///               `strlen(str)` bytes. If `len` is larger than the
  ///               allocated size of `src`, the behaviour is undefined.
  /// @param must_append If true, append the contents of `str` to the current
  ///                    contents of the register. Note that regardless of
  ///                    `must_append`, this function will append when `name`
  ///                    is an uppercase letter.
  /// @param yank_type MCHAR, MLINE, MBLOCK or MAUTO
  /// @param block_len width of visual block
  void write_reg_contents_ex(int name,
                             const char_u *str,
                             ssize_t len,
                             int must_append,
                             int yank_type,
                             long block_len)
  {
    if (len < 0) {
      len = (ssize_t) STRLEN(str);
    }
  
    /* Special case: '/' search pattern */
    if (name == '/') {
      set_last_search_pat(str, RE_SEARCH, TRUE, TRUE);
      return;
    }
  
    if (name == '=') {
      size_t offset = 0;
      size_t totlen = (size_t) len;
  
      if (must_append && expr_line) {
        // append has been specified and expr_line already exists, so we'll
        // append the new string to expr_line.
        size_t exprlen = STRLEN(expr_line);
  
        totlen += exprlen;
        offset = exprlen;
      }
  
      // modify the global expr_line, extend/shrink it if necessary (realloc).
      // Copy the input string into the adjusted memory at the specified
      // offset.
      expr_line = xrealloc(expr_line, totlen + 1);
      memcpy(expr_line + offset, str, (size_t) len);
      expr_line[totlen] = NUL;
  
      return;
    }
  
    if (name == '_') {        // black hole: nothing to do
      return;
    }
  
    struct yankreg  *old_y_previous, *old_y_current;
    if (!init_write_reg(name, &old_y_previous, &old_y_current, must_append)) {
  	    return;
    }
    str_to_reg(y_current, yank_type, str, len, block_len, false);
    finish_write_reg(name, old_y_previous, old_y_current);
  }
  
  /// str_to_reg - Put a string into a register.
  ///
  /// When the register is not empty, the string is appended.
  ///
  /// @param y_ptr pointer to yank register
  /// @param yank_type MCHAR, MLINE, MBLOCK or MAUTO
  /// @param str string or list of strings to put in register
  /// @param len length of the string (Ignored when str_list=true.)
  /// @param blocklen width of visual block, or -1 for "I don't know."
  /// @param str_list True if str is `char_u **`.
  static void str_to_reg(struct yankreg *y_ptr, int yank_type, const char_u *str,
                         size_t len, colnr_T blocklen, bool str_list)
    FUNC_ATTR_NONNULL_ALL
  {
    if (y_ptr->y_array == NULL) {  // NULL means empty register
      y_ptr->y_size = 0;
    }
  
    int type = yank_type;  // MCHAR, MLINE or MBLOCK
    if (yank_type == MAUTO) {
      type = ((str_list ||
               (len > 0 && (str[len - 1] == NL || str[len - 1] == CAR)))
              ? MLINE : MCHAR);
    }
  
    size_t newlines = 0;
    bool extraline = false;  // extra line at the end
    bool append = false;     // append to last line in register
  
    // Count the number of lines within the string
    if (str_list) {
      for (char_u **ss = (char_u **) str; *ss != NULL; ++ss) {
        newlines++;
      }
    } else {
      newlines = memcnt(str, '\n', len);
      if (type == MCHAR || len == 0 || str[len - 1] != '\n') {
        extraline = 1;
        ++newlines;         // count extra newline at the end
      }
      if (y_ptr->y_size > 0 && y_ptr->y_type == MCHAR) {
        append = true;
        --newlines;         // uncount newline when appending first line
      }
    }
  
  
    // Grow the register array to hold the pointers to the new lines.
    char_u **pp = xrealloc(y_ptr->y_array,
                           (y_ptr->y_size + newlines) * sizeof(char_u *));
    y_ptr->y_array = pp;
  
    linenr_T lnum = y_ptr->y_size;  // The current line number.
  
    // If called with `blocklen < 0`, we have to update the yank reg's width.
    size_t maxlen = 0;
  
    // Find the end of each line and save it into the array.
    if (str_list) {
      for (char_u **ss = (char_u **) str; *ss != NULL; ++ss, ++lnum) {
        size_t ss_len = STRLEN(*ss);
        pp[lnum] = xmemdupz(*ss, ss_len);
        if (ss_len > maxlen) {
          maxlen = ss_len;
        }
      }
    } else {
      size_t line_len;
      for (const char_u *start = str, *end = str + len;
           start < end + extraline;
           start += line_len + 1, lnum++) {
        line_len = (const char_u *) xmemscan(start, '\n', end - start) - start;
        if (line_len > maxlen) {
          maxlen = line_len;
        }
  
        // When appending, copy the previous line and free it after.
        size_t extra = append ? STRLEN(pp[--lnum]) : 0;
        char_u *s = xmallocz(line_len + extra);
        memcpy(s, pp[lnum], extra);
        memcpy(s + extra, start, line_len);
        ssize_t s_len = extra + line_len;
  
        if (append) {
          free(pp[lnum]);
          append = false;  // only first line is appended
        }
        pp[lnum] = s;
  
        // Convert NULs to '\n' to prevent truncation.
        memchrsub(pp[lnum], NUL, '\n', s_len);
      }
    }
    y_ptr->y_type = type;
    y_ptr->y_size = lnum;
    if (type == MBLOCK) {
      y_ptr->y_width = (blocklen == -1 ? (colnr_T) maxlen - 1 : blocklen);
    } else {
      y_ptr->y_width = 0;
    }
  }
  
  void clear_oparg(oparg_T *oap)
  {
    memset(oap, 0, sizeof(oparg_T));
  }
  
  
  /*
   *  Count the number of bytes, characters and "words" in a line.
   *
   *  "Words" are counted by looking for boundaries between non-space and
   *  space characters.  (it seems to produce results that match 'wc'.)
   *
   *  Return value is byte count; word count for the line is added to "*wc".
   *  Char count is added to "*cc".
   *
   *  The function will only examine the first "limit" characters in the
   *  line, stopping if it encounters an end-of-line (NUL byte).  In that
   *  case, eol_size will be added to the character count to account for
   *  the size of the EOL character.
   */
  static long line_count_info(char_u *line, long *wc, long *cc, long limit, int eol_size)
  {
    long i;
    long words = 0;
    long chars = 0;
    int is_word = 0;
  
    for (i = 0; i < limit && line[i] != NUL; ) {
      if (is_word) {
        if (vim_isspace(line[i])) {
          words++;
          is_word = 0;
        }
      } else if (!vim_isspace(line[i]))
        is_word = 1;
      ++chars;
      i += (*mb_ptr2len)(line + i);
    }
  
    if (is_word)
      words++;
    *wc += words;
  
    /* Add eol_size if the end of line was reached before hitting limit. */
    if (i < limit && line[i] == NUL) {
      i += eol_size;
      chars += eol_size;
    }
    *cc += chars;
    return i;
  }
  
  /*
   * Give some info about the position of the cursor (for "g CTRL-G").
   * In Visual mode, give some info about the selected region.  (In this case,
   * the *_count_cursor variables store running totals for the selection.)
   */
  void cursor_pos_info(void)
  {
    char_u      *p;
    char_u buf1[50];
    char_u buf2[40];
    linenr_T lnum;
    long byte_count = 0;
    long byte_count_cursor = 0;
    long char_count = 0;
    long char_count_cursor = 0;
    long word_count = 0;
    long word_count_cursor = 0;
    int eol_size;
    long last_check = 100000L;
    long line_count_selected = 0;
    pos_T min_pos, max_pos;
    oparg_T oparg;
    struct block_def bd;
    const int l_VIsual_active = VIsual_active;
    const int l_VIsual_mode = VIsual_mode;
  
    /*
     * Compute the length of the file in characters.
     */
    if (curbuf->b_ml.ml_flags & ML_EMPTY) {
      MSG(_(no_lines_msg));
    } else {
      if (get_fileformat(curbuf) == EOL_DOS)
        eol_size = 2;
      else
        eol_size = 1;
  
      if (l_VIsual_active) {
        if (lt(VIsual, curwin->w_cursor)) {
          min_pos = VIsual;
          max_pos = curwin->w_cursor;
        } else {
          min_pos = curwin->w_cursor;
          max_pos = VIsual;
        }
        if (*p_sel == 'e' && max_pos.col > 0)
          --max_pos.col;
  
        if (l_VIsual_mode == Ctrl_V) {
          char_u * saved_sbr = p_sbr;
  
          /* Make 'sbr' empty for a moment to get the correct size. */
          p_sbr = empty_option;
          oparg.is_VIsual = true;
          oparg.block_mode = true;
          oparg.op_type = OP_NOP;
          getvcols(curwin, &min_pos, &max_pos,
              &oparg.start_vcol, &oparg.end_vcol);
          p_sbr = saved_sbr;
          if (curwin->w_curswant == MAXCOL)
            oparg.end_vcol = MAXCOL;
          /* Swap the start, end vcol if needed */
          if (oparg.end_vcol < oparg.start_vcol) {
            oparg.end_vcol += oparg.start_vcol;
            oparg.start_vcol = oparg.end_vcol - oparg.start_vcol;
            oparg.end_vcol -= oparg.start_vcol;
          }
        }
        line_count_selected = max_pos.lnum - min_pos.lnum + 1;
      }
  
      for (lnum = 1; lnum <= curbuf->b_ml.ml_line_count; ++lnum) {
        /* Check for a CTRL-C every 100000 characters. */
        if (byte_count > last_check) {
          os_breakcheck();
          if (got_int)
            return;
          last_check = byte_count + 100000L;
        }
  
        /* Do extra processing for VIsual mode. */
        if (l_VIsual_active
            && lnum >= min_pos.lnum && lnum <= max_pos.lnum) {
          char_u      *s = NULL;
          long len = 0L;
  
          switch (l_VIsual_mode) {
          case Ctrl_V:
            virtual_op = virtual_active();
            block_prep(&oparg, &bd, lnum, 0);
            virtual_op = MAYBE;
            s = bd.textstart;
            len = (long)bd.textlen;
            break;
          case 'V':
            s = ml_get(lnum);
            len = MAXCOL;
            break;
          case 'v':
          {
            colnr_T start_col = (lnum == min_pos.lnum)
                                ? min_pos.col : 0;
            colnr_T end_col = (lnum == max_pos.lnum)
                              ? max_pos.col - start_col + 1 : MAXCOL;
  
            s = ml_get(lnum) + start_col;
            len = end_col;
          }
          break;
          }
          if (s != NULL) {
            byte_count_cursor += line_count_info(s, &word_count_cursor,
                &char_count_cursor, len, eol_size);
            if (lnum == curbuf->b_ml.ml_line_count
                && !curbuf->b_p_eol
                && curbuf->b_p_bin
                && (long)STRLEN(s) < len)
              byte_count_cursor -= eol_size;
          }
        } else {
          /* In non-visual mode, check for the line the cursor is on */
          if (lnum == curwin->w_cursor.lnum) {
            word_count_cursor += word_count;
            char_count_cursor += char_count;
            byte_count_cursor = byte_count +
                                line_count_info(ml_get(lnum),
                &word_count_cursor, &char_count_cursor,
                (long)(curwin->w_cursor.col + 1), eol_size);
          }
        }
        /* Add to the running totals */
        byte_count += line_count_info(ml_get(lnum), &word_count,
            &char_count, (long)MAXCOL, eol_size);
      }
  
      /* Correction for when last line doesn't have an EOL. */
      if (!curbuf->b_p_eol && curbuf->b_p_bin)
        byte_count -= eol_size;
  
      if (l_VIsual_active) {
        if (l_VIsual_mode == Ctrl_V && curwin->w_curswant < MAXCOL) {
          getvcols(curwin, &min_pos, &max_pos, &min_pos.col,
              &max_pos.col);
          vim_snprintf((char *)buf1, sizeof(buf1), _("%" PRId64 " Cols; "),
              (int64_t)(oparg.end_vcol - oparg.start_vcol + 1));
        } else
          buf1[0] = NUL;
  
        if (char_count_cursor == byte_count_cursor
            && char_count == byte_count)
          vim_snprintf((char *)IObuff, IOSIZE,
              _("Selected %s%" PRId64 " of %" PRId64 " Lines; %" PRId64
                " of %" PRId64 " Words; %" PRId64 " of %" PRId64 " Bytes"),
              buf1, (int64_t)line_count_selected,
              (int64_t)curbuf->b_ml.ml_line_count,
              (int64_t)word_count_cursor, (int64_t)word_count,
              (int64_t)byte_count_cursor, (int64_t)byte_count);
        else
          vim_snprintf((char *)IObuff, IOSIZE,
              _("Selected %s%" PRId64 " of %" PRId64 " Lines; %" PRId64
                " of %" PRId64 " Words; %" PRId64 " of %" PRId64
                " Chars; %" PRId64 " of %" PRId64 " Bytes"),
              buf1, (int64_t)line_count_selected,
              (int64_t)curbuf->b_ml.ml_line_count,
              (int64_t)word_count_cursor, (int64_t)word_count,
              (int64_t)char_count_cursor, (int64_t)char_count,
              (int64_t)byte_count_cursor, (int64_t)byte_count);
      } else {
        p = get_cursor_line_ptr();
        validate_virtcol();
        col_print(buf1, sizeof(buf1), (int)curwin->w_cursor.col + 1,
            (int)curwin->w_virtcol + 1);
        col_print(buf2, sizeof(buf2), (int)STRLEN(p), linetabsize(p));
  
        if (char_count_cursor == byte_count_cursor
            && char_count == byte_count)
          vim_snprintf((char *)IObuff, IOSIZE,
              _("Col %s of %s; Line %" PRId64 " of %" PRId64 "; Word %" PRId64
                " of %" PRId64 "; Byte %" PRId64 " of %" PRId64 ""),
              (char *)buf1, (char *)buf2,
              (int64_t)curwin->w_cursor.lnum,
              (int64_t)curbuf->b_ml.ml_line_count,
              (int64_t)word_count_cursor, (int64_t)word_count,
              (int64_t)byte_count_cursor, (int64_t)byte_count);
        else
          vim_snprintf((char *)IObuff, IOSIZE,
              _(
                  "Col %s of %s; Line %" PRId64 " of %" PRId64 "; Word %" PRId64
                  " of %" PRId64 "; Char %" PRId64 " of %" PRId64
                  "; Byte %" PRId64 " of %" PRId64 ""),
              (char *)buf1, (char *)buf2,
              (int64_t)curwin->w_cursor.lnum,
              (int64_t)curbuf->b_ml.ml_line_count,
              (int64_t)word_count_cursor, (int64_t)word_count,
              (int64_t)char_count_cursor, (int64_t)char_count,
              (int64_t)byte_count_cursor, (int64_t)byte_count);
      }
  
      byte_count = bomb_size();
      if (byte_count > 0)
        sprintf((char *)IObuff + STRLEN(IObuff), _("(+%" PRId64 " for BOM)"),
            (int64_t)byte_count);
      /* Don't shorten this message, the user asked for it. */
      p = p_shm;
      p_shm = (char_u *)"";
      msg(IObuff);
      p_shm = p;
    }
  }
  
  static void free_register(struct yankreg *reg)
  {
    // Save 'y_current' into 'curr'
    struct yankreg *curr = y_current;
    // Set it to 'y_current' since 'free_yank_all' operates on it
    y_current = reg;
    free_yank_all();
    // Restore 'y_current'
    y_current = curr;
  }
  
  // return target register
  static struct yankreg* adjust_clipboard_name(int *name) {
    if (*name == '*' || *name == '+') {
      if(!eval_has_provider("clipboard")) {
        EMSG("clipboard: provider is not available");
        return NULL;
      }
      return &y_regs[CLIP_REGISTER];
    } else if ((*name == NUL || *name == CB_LATEST) && (cb_flags & CB_UNNAMEDMASK)) {
      if(!eval_has_provider("clipboard")) {
        if (!clipboard_didwarn_unnamed) {
          msg((char_u*)"clipboard: provider not available, ignoring clipboard=unnamed[plus]");
          clipboard_didwarn_unnamed = true;
        }
        return NULL;
      }
      struct yankreg* target;
      if (*name == CB_LATEST) {
        target = y_current;
      } else {
        target = &y_regs[0];
      }
      if (cb_flags & CB_UNNAMEDPLUS) {
        *name = '+';
      } else {
        *name = '*';
      }
      return target; // unnamed register
    }
    // don't do anything for other register names
    return NULL;
  }
  
  static void get_clipboard(int name)
  {
    struct yankreg* reg = adjust_clipboard_name(&name);
    if (reg == NULL) {
      return;
    }
    free_register(reg);
  
    list_T *args = list_alloc();
    char_u regname = name;
    list_append_string(args, &regname, 1);
  
    typval_T result = eval_call_provider("clipboard", "get", args);
  
    if (result.v_type != VAR_LIST) {
      goto err;
    }
  
    list_T *res = result.vval.v_list, *lines = NULL;
    if (res->lv_len == 2 && res->lv_first->li_tv.v_type == VAR_LIST) {
      lines = res->lv_first->li_tv.vval.v_list;
      if (res->lv_last->li_tv.v_type != VAR_STRING) {
        goto err;
      }
      char_u* regtype = res->lv_last->li_tv.vval.v_string;
      if (regtype == NULL || strlen((char*)regtype) != 1) {
        goto err;
      }
      switch (regtype[0]) {
      case 'v': case 'c':
        reg->y_type = MCHAR;
        break;
      case 'V': case 'l':
        reg->y_type = MLINE;
        break;
      case 'b': case Ctrl_V:
        reg->y_type = MBLOCK;
        break;
      default:
        goto err;
      }
    } else {
      lines = res;
      // provider did not specify regtype, calculate it below
      reg->y_type = MAUTO;
    }
  
    reg->y_array = xcalloc(lines->lv_len, sizeof(uint8_t *));
    reg->y_size = lines->lv_len;
  
    int i = 0;
    for (listitem_T *li = lines->lv_first; li != NULL; li = li->li_next) {
      if (li->li_tv.v_type != VAR_STRING) {
        goto err;
      }
      reg->y_array[i++] = (uint8_t *)xstrdup((char *)li->li_tv.vval.v_string);
    }
  
    if (reg->y_type == MAUTO) {
      if (reg->y_size > 0 && strlen((char*)reg->y_array[reg->y_size-1]) == 0) {
        reg->y_type = MLINE;
        free(reg->y_array[reg->y_size-1]);
        reg->y_size--;
      } else {
        reg->y_type = MCHAR;
      }
    } else if (reg->y_type == MBLOCK) {
      int maxlen = 0;
      for (int i = 0; i < reg->y_size; i++) {
        int rowlen = STRLEN(reg->y_array[i]);
        if (rowlen > maxlen) {
          maxlen = rowlen;
        }
      }
      reg->y_width = maxlen-1;
    }
  
    return;
  
  err:
    if (reg->y_array) {
      for (int i = 0; i < reg->y_size; i++) {
        free(reg->y_array[i]);
      }
      free(reg->y_array);
    }
    reg->y_array = NULL;
    reg->y_size = 0;
    EMSG("clipboard: provider returned invalid data");
  }
  
  static void set_clipboard(int name)
  {
    struct yankreg* reg = adjust_clipboard_name(&name);
    if (reg == NULL) {
      return;
    }
  
    list_T *lines = list_alloc();
  
    for (int i = 0; i < reg->y_size; i++) {
      list_append_string(lines, reg->y_array[i], -1);
    }
  
    list_T *args = list_alloc();
    list_append_list(args, lines);
  
    char_u regtype;
    switch (reg->y_type) {
    case MLINE:
      regtype = 'V';
      list_append_string(lines, (char_u*)"", 0);
      break;
    case MCHAR:
      regtype = 'v';
      break;
    case MBLOCK:
      regtype = 'b';
      break;
    }
    list_append_string(args, &regtype, 1);
  
    char_u regname = name;
    list_append_string(args, &regname, 1);
  
    (void)eval_call_provider("clipboard", "set", args);
  }
  