text: /* See LICENSE for license details. */
  #include <ctype.h>
  #include <errno.h>
  #include <fcntl.h>
  #include <limits.h>
  #include <pwd.h>
  #include <stdarg.h>
  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  #include <signal.h>
  #include <sys/ioctl.h>
  #include <sys/select.h>
  #include <sys/types.h>
  #include <sys/wait.h>
  #include <termios.h>
  #include <unistd.h>
  #include <wchar.h>
  
  #include "st.h"
  #include "win.h"
  
  #if   defined(__linux)
   #include <pty.h>
  #elif defined(__OpenBSD__) || defined(__NetBSD__) || defined(__APPLE__)
   #include <util.h>
  #elif defined(__FreeBSD__) || defined(__DragonFly__)
   #include <libutil.h>
  #endif
  
  /* Arbitrary sizes */
  #define UTF_INVALID   0xFFFD
  #define UTF_SIZ       4
  #define ESC_BUF_SIZ   (128*UTF_SIZ)
  #define ESC_ARG_SIZ   16
  #define STR_BUF_SIZ   ESC_BUF_SIZ
  #define STR_ARG_SIZ   ESC_ARG_SIZ
  
  /* macros */
  #define IS_SET(flag)    ((term.mode & (flag)) != 0)
  #define ISCONTROLC0(c)    (BETWEEN(c, 0, 0x1f) || (c) == 0x7f)
  #define ISCONTROLC1(c)    (BETWEEN(c, 0x80, 0x9f))
  #define ISCONTROL(c)    (ISCONTROLC0(c) || ISCONTROLC1(c))
  #define ISDELIM(u)      (u && wcschr(worddelimiters, u))
  
  enum term_mode {
    MODE_WRAP        = 1 << 0,
    MODE_INSERT      = 1 << 1,
    MODE_ALTSCREEN   = 1 << 2,
    MODE_CRLF        = 1 << 3,
    MODE_ECHO        = 1 << 4,
    MODE_PRINT       = 1 << 5,
    MODE_UTF8        = 1 << 6,
  };
  
  enum cursor_movement {
    CURSOR_SAVE,
    CURSOR_LOAD
  };
  
  enum cursor_state {
    CURSOR_DEFAULT  = 0,
    CURSOR_WRAPNEXT = 1,
    CURSOR_ORIGIN   = 2
  };
  
  enum charset {
    CS_GRAPHIC0,
    CS_GRAPHIC1,
    CS_UK,
    CS_USA,
    CS_MULTI,
    CS_GER,
    CS_FIN
  };
  
  enum escape_state {
    ESC_START      = 1,
    ESC_CSI        = 2,
    ESC_STR        = 4,  /* DCS, OSC, PM, APC */
    ESC_ALTCHARSET = 8,
    ESC_STR_END    = 16, /* a final string was encountered */
    ESC_TEST       = 32, /* Enter in test mode */
    ESC_UTF8       = 64,
  };
  
  typedef struct {
    Glyph attr; /* current char attributes */
    int x;
    int y;
    char state;
  } TCursor;
  
  typedef struct {
    int mode;
    int type;
    int snap;
    /*
     * Selection variables:
     * nb – normalized coordinates of the beginning of the selection
     * ne – normalized coordinates of the end of the selection
     * ob – original coordinates of the beginning of the selection
     * oe – original coordinates of the end of the selection
     */
    struct {
      int x, y;
    } nb, ne, ob, oe;
  
    int alt;
  } Selection;
  
  /* Internal representation of the screen */
  typedef struct {
    int row;      /* nb row */
    int col;      /* nb col */
    Line *line;   /* screen */
    Line *alt;    /* alternate screen */
    int *dirty;   /* dirtyness of lines */
    TCursor c;    /* cursor */
    int ocx;      /* old cursor col */
    int ocy;      /* old cursor row */
    int top;      /* top    scroll limit */
    int bot;      /* bottom scroll limit */
    int mode;     /* terminal mode flags */
    int esc;      /* escape state flags */
    char trantbl[4]; /* charset table translation */
    int charset;  /* current charset */
    int icharset; /* selected charset for sequence */
    int *tabs;
    Rune lastc;   /* last printed char outside of sequence, 0 if control */
  } Term;
  
  /* CSI Escape sequence structs */
  /* ESC '[' [[ [<priv>] <arg> [;]] <mode> [<mode>]] */
  typedef struct {
    char buf[ESC_BUF_SIZ]; /* raw string */
    size_t len;            /* raw string length */
    char priv;
    int arg[ESC_ARG_SIZ];
    int narg;              /* nb of args */
    char mode[2];
  } CSIEscape;
  
  /* STR Escape sequence structs */
  /* ESC type [[ [<priv>] <arg> [;]] <mode>] ESC '\' */
  typedef struct {
    char type;             /* ESC type ... */
    char *buf;             /* allocated raw string */
    size_t siz;            /* allocation size */
    size_t len;            /* raw string length */
    char *args[STR_ARG_SIZ];
    int narg;              /* nb of args */
  } STREscape;
  
  static void execsh(char *, char **);
  static void stty(char **);
  static void sigchld(int);
  static void ttywriteraw(const char *, size_t);
  
  static void csidump(void);
  static void csihandle(void);
  static void csiparse(void);
  static void csireset(void);
  static int eschandle(uchar);
  static void strdump(void);
  static void strhandle(void);
  static void strparse(void);
  static void strreset(void);
  
  static void tprinter(char *, size_t);
  static void tdumpsel(void);
  static void tdumpline(int);
  static void tdump(void);
  static void tclearregion(int, int, int, int);
  static void tcursor(int);
  static void tdeletechar(int);
  static void tdeleteline(int);
  static void tinsertblank(int);
  static void tinsertblankline(int);
  static int tlinelen(int);
  static void tmoveto(int, int);
  static void tmoveato(int, int);
  static void tnewline(int);
  static void tputtab(int);
  static void tputc(Rune);
  static void treset(void);
  static void tscrollup(int, int);
  static void tscrolldown(int, int);
  static void tsetattr(int *, int);
  static void tsetchar(Rune, Glyph *, int, int);
  static void tsetdirt(int, int);
  static void tsetscroll(int, int);
  static void tswapscreen(void);
  static void tsetmode(int, int, int *, int);
  static int twrite(const char *, int, int);
  static void tfulldirt(void);
  static void tcontrolcode(uchar );
  static void tdectest(char );
  static void tdefutf8(char);
  static int32_t tdefcolor(int *, int *, int);
  static void tdeftran(char);
  static void tstrsequence(uchar);
  
  static void drawregion(int, int, int, int);
  
  static void selnormalize(void);
  static void selscroll(int, int);
  static void selsnap(int *, int *, int);
  
  static size_t utf8decode(const char *, Rune *, size_t);
  static Rune utf8decodebyte(char, size_t *);
  static char utf8encodebyte(Rune, size_t);
  static size_t utf8validate(Rune *, size_t);
  
  static char *base64dec(const char *);
  static char base64dec_getc(const char **);
  
  static ssize_t xwrite(int, const char *, size_t);
  
  /* Globals */
  static Term term;
  static Selection sel;
  static CSIEscape csiescseq;
  static STREscape strescseq;
  static int iofd = 1;
  static int cmdfd;
  static pid_t pid;
  
  static uchar utfbyte[UTF_SIZ + 1] = {0x80,    0, 0xC0, 0xE0, 0xF0};
  static uchar utfmask[UTF_SIZ + 1] = {0xC0, 0x80, 0xE0, 0xF0, 0xF8};
  static Rune utfmin[UTF_SIZ + 1] = {       0,    0,  0x80,  0x800,  0x10000};
  static Rune utfmax[UTF_SIZ + 1] = {0x10FFFF, 0x7F, 0x7FF, 0xFFFF, 0x10FFFF};
  
  #include <time.h>
  static int su = 0;
  struct timespec sutv;
  
  static void
  tsync_begin()
  {
  	clock_gettime(CLOCK_MONOTONIC, &sutv);
  	su = 1;
  }
  
  static void
  tsync_end()
  {
  	su = 0;
  }
  
  int
  tinsync(uint timeout)
  {
  	struct timespec now;
  	if (su && !clock_gettime(CLOCK_MONOTONIC, &now)
  	       && TIMEDIFF(now, sutv) >= timeout)
  		su = 0;
  	return su;
  }
  
  ssize_t
  xwrite(int fd, const char *s, size_t len)
  {
    size_t aux = len;
    ssize_t r;
  
    while (len > 0) {
      r = write(fd, s, len);
      if (r < 0)
        return r;
      len -= r;
      s += r;
    }
  
    return aux;
  }
  
  void *
  xmalloc(size_t len)
  {
    void *p;
  
    if (!(p = malloc(len)))
      die("malloc: %s\n", strerror(errno));
  
    return p;
  }
  
  void *
  xrealloc(void *p, size_t len)
  {
    if ((p = realloc(p, len)) == NULL)
      die("realloc: %s\n", strerror(errno));
  
    return p;
  }
  
  char *
  xstrdup(char *s)
  {
    if ((s = strdup(s)) == NULL)
      die("strdup: %s\n", strerror(errno));
  
    return s;
  }
  
  size_t
  utf8decode(const char *c, Rune *u, size_t clen)
  {
    size_t i, j, len, type;
    Rune udecoded;
  
    *u = UTF_INVALID;
    if (!clen)
      return 0;
    udecoded = utf8decodebyte(c[0], &len);
    if (!BETWEEN(len, 1, UTF_SIZ))
      return 1;
    for (i = 1, j = 1; i < clen && j < len; ++i, ++j) {
      udecoded = (udecoded << 6) | utf8decodebyte(c[i], &type);
      if (type != 0)
        return j;
    }
    if (j < len)
      return 0;
    *u = udecoded;
    utf8validate(u, len);
  
    return len;
  }
  
  Rune
  utf8decodebyte(char c, size_t *i)
  {
    for (*i = 0; *i < LEN(utfmask); ++(*i))
      if (((uchar)c & utfmask[*i]) == utfbyte[*i])
        return (uchar)c & ~utfmask[*i];
  
    return 0;
  }
  
  size_t
  utf8encode(Rune u, char *c)
  {
    size_t len, i;
  
    len = utf8validate(&u, 0);
    if (len > UTF_SIZ)
      return 0;
  
    for (i = len - 1; i != 0; --i) {
      c[i] = utf8encodebyte(u, 0);
      u >>= 6;
    }
    c[0] = utf8encodebyte(u, len);
  
    return len;
  }
  
  char
  utf8encodebyte(Rune u, size_t i)
  {
    return utfbyte[i] | (u & ~utfmask[i]);
  }
  
  size_t
  utf8validate(Rune *u, size_t i)
  {
    if (!BETWEEN(*u, utfmin[i], utfmax[i]) || BETWEEN(*u, 0xD800, 0xDFFF))
      *u = UTF_INVALID;
    for (i = 1; *u > utfmax[i]; ++i)
      ;
  
    return i;
  }
  
  static const char base64_digits[] = {
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 62, 0, 0, 0,
    63, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 0, 0, 0, -1, 0, 0, 0, 0, 1,
    2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21,
    22, 23, 24, 25, 0, 0, 0, 0, 0, 0, 26, 27, 28, 29, 30, 31, 32, 33, 34,
    35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
  };
  
  char
  base64dec_getc(const char **src)
  {
    while (**src && !isprint(**src))
      (*src)++;
    return **src ? *((*src)++) : '=';  /* emulate padding if string ends */
  }
  
  char *
  base64dec(const char *src)
  {
    size_t in_len = strlen(src);
    char *result, *dst;
  
    if (in_len % 4)
      in_len += 4 - (in_len % 4);
    result = dst = xmalloc(in_len / 4 * 3 + 1);
    while (*src) {
      int a = base64_digits[(unsigned char) base64dec_getc(&src)];
      int b = base64_digits[(unsigned char) base64dec_getc(&src)];
      int c = base64_digits[(unsigned char) base64dec_getc(&src)];
      int d = base64_digits[(unsigned char) base64dec_getc(&src)];
  
      /* invalid input. 'a' can be -1, e.g. if src is "\n" (c-str) */
      if (a == -1 || b == -1)
        break;
  
      *dst++ = (a << 2) | ((b & 0x30) >> 4);
      if (c == -1)
        break;
      *dst++ = ((b & 0x0f) << 4) | ((c & 0x3c) >> 2);
      if (d == -1)
        break;
      *dst++ = ((c & 0x03) << 6) | d;
    }
    *dst = '\0';
    return result;
  }
  
  void
  selinit(void)
  {
    sel.mode = SEL_IDLE;
    sel.snap = 0;
    sel.ob.x = -1;
  }
  
  int
  tlinelen(int y)
  {
    int i = term.col;
  
    if (term.line[y][i - 1].mode & ATTR_WRAP)
      return i;
  
    while (i > 0 && term.line[y][i - 1].u == ' ')
      --i;
  
    return i;
  }
  
  void
  selstart(int col, int row, int snap)
  {
    selclear();
    sel.mode = SEL_EMPTY;
    sel.type = SEL_REGULAR;
    sel.alt = IS_SET(MODE_ALTSCREEN);
    sel.snap = snap;
    sel.oe.x = sel.ob.x = col;
    sel.oe.y = sel.ob.y = row;
    selnormalize();
  
    if (sel.snap != 0)
      sel.mode = SEL_READY;
    tsetdirt(sel.nb.y, sel.ne.y);
  }
  
  void
  selextend(int col, int row, int type, int done)
  {
    int oldey, oldex, oldsby, oldsey, oldtype;
  
    if (sel.mode == SEL_IDLE)
      return;
    if (done && sel.mode == SEL_EMPTY) {
      selclear();
      return;
    }
  
    oldey = sel.oe.y;
    oldex = sel.oe.x;
    oldsby = sel.nb.y;
    oldsey = sel.ne.y;
    oldtype = sel.type;
  
    sel.oe.x = col;
    sel.oe.y = row;
    selnormalize();
    sel.type = type;
  
    if (oldey != sel.oe.y || oldex != sel.oe.x || oldtype != sel.type || sel.mode == SEL_EMPTY)
      tsetdirt(MIN(sel.nb.y, oldsby), MAX(sel.ne.y, oldsey));
  
    sel.mode = done ? SEL_IDLE : SEL_READY;
  }
  
  void
  selnormalize(void)
  {
    int i;
  
    if (sel.type == SEL_REGULAR && sel.ob.y != sel.oe.y) {
      sel.nb.x = sel.ob.y < sel.oe.y ? sel.ob.x : sel.oe.x;
      sel.ne.x = sel.ob.y < sel.oe.y ? sel.oe.x : sel.ob.x;
    } else {
      sel.nb.x = MIN(sel.ob.x, sel.oe.x);
      sel.ne.x = MAX(sel.ob.x, sel.oe.x);
    }
    sel.nb.y = MIN(sel.ob.y, sel.oe.y);
    sel.ne.y = MAX(sel.ob.y, sel.oe.y);
  
    selsnap(&sel.nb.x, &sel.nb.y, -1);
    selsnap(&sel.ne.x, &sel.ne.y, +1);
  
    /* expand selection over line breaks */
    if (sel.type == SEL_RECTANGULAR)
      return;
    i = tlinelen(sel.nb.y);
    if (i < sel.nb.x)
      sel.nb.x = i;
    if (tlinelen(sel.ne.y) <= sel.ne.x)
      sel.ne.x = term.col - 1;
  }
  
  int
  selected(int x, int y)
  {
    if (sel.mode == SEL_EMPTY || sel.ob.x == -1 ||
        sel.alt != IS_SET(MODE_ALTSCREEN))
      return 0;
  
    if (sel.type == SEL_RECTANGULAR)
      return BETWEEN(y, sel.nb.y, sel.ne.y)
          && BETWEEN(x, sel.nb.x, sel.ne.x);
  
    return BETWEEN(y, sel.nb.y, sel.ne.y)
        && (y != sel.nb.y || x >= sel.nb.x)
        && (y != sel.ne.y || x <= sel.ne.x);
  }
  
  void
  selsnap(int *x, int *y, int direction)
  {
    int newx, newy, xt, yt;
    int delim, prevdelim;
    Glyph *gp, *prevgp;
  
    switch (sel.snap) {
    case SNAP_WORD:
      /*
       * Snap around if the word wraps around at the end or
       * beginning of a line.
       */
      prevgp = &term.line[*y][*x];
      prevdelim = ISDELIM(prevgp->u);
      for (;;) {
        newx = *x + direction;
        newy = *y;
        if (!BETWEEN(newx, 0, term.col - 1)) {
          newy += direction;
          newx = (newx + term.col) % term.col;
          if (!BETWEEN(newy, 0, term.row - 1))
            break;
  
          if (direction > 0)
            yt = *y, xt = *x;
          else
            yt = newy, xt = newx;
          if (!(term.line[yt][xt].mode & ATTR_WRAP))
            break;
        }
  
        if (newx >= tlinelen(newy))
          break;
  
        gp = &term.line[newy][newx];
        delim = ISDELIM(gp->u);
        if (!(gp->mode & ATTR_WDUMMY) && (delim != prevdelim
            || (delim && gp->u != prevgp->u)))
          break;
  
        *x = newx;
        *y = newy;
        prevgp = gp;
        prevdelim = delim;
      }
      break;
    case SNAP_LINE:
      /*
       * Snap around if the the previous line or the current one
       * has set ATTR_WRAP at its end. Then the whole next or
       * previous line will be selected.
       */
      *x = (direction < 0) ? 0 : term.col - 1;
      if (direction < 0) {
        for (; *y > 0; *y += direction) {
          if (!(term.line[*y-1][term.col-1].mode
              & ATTR_WRAP)) {
            break;
          }
        }
      } else if (direction > 0) {
        for (; *y < term.row-1; *y += direction) {
          if (!(term.line[*y][term.col-1].mode
              & ATTR_WRAP)) {
            break;
          }
        }
      }
      break;
    }
  }
  
  char *
  getsel(void)
  {
    char *str, *ptr;
    int y, bufsize, lastx, linelen;
    Glyph *gp, *last;
  
    if (sel.ob.x == -1)
      return NULL;
  
    bufsize = (term.col+1) * (sel.ne.y-sel.nb.y+1) * UTF_SIZ;
    ptr = str = xmalloc(bufsize);
  
    /* append every set & selected glyph to the selection */
    for (y = sel.nb.y; y <= sel.ne.y; y++) {
      if ((linelen = tlinelen(y)) == 0) {
        *ptr++ = '\n';
        continue;
      }
  
      if (sel.type == SEL_RECTANGULAR) {
        gp = &term.line[y][sel.nb.x];
        lastx = sel.ne.x;
      } else {
        gp = &term.line[y][sel.nb.y == y ? sel.nb.x : 0];
        lastx = (sel.ne.y == y) ? sel.ne.x : term.col-1;
      }
      last = &term.line[y][MIN(lastx, linelen-1)];
      while (last >= gp && last->u == ' ')
        --last;
  
      for ( ; gp <= last; ++gp) {
        if (gp->mode & ATTR_WDUMMY)
          continue;
  
        ptr += utf8encode(gp->u, ptr);
      }
  
      /*
       * Copy and pasting of line endings is inconsistent
       * in the inconsistent terminal and GUI world.
       * The best solution seems like to produce '\n' when
       * something is copied from st and convert '\n' to
       * '\r', when something to be pasted is received by
       * st.
       * FIXME: Fix the computer world.
       */
      if ((y < sel.ne.y || lastx >= linelen) &&
          (!(last->mode & ATTR_WRAP) || sel.type == SEL_RECTANGULAR))
        *ptr++ = '\n';
    }
    *ptr = 0;
    return str;
  }
  
  void
  selclear(void)
  {
    if (sel.ob.x == -1)
      return;
    sel.mode = SEL_IDLE;
    sel.ob.x = -1;
    tsetdirt(sel.nb.y, sel.ne.y);
  }
  
  void
  die(const char *errstr, ...)
  {
    va_list ap;
  
    va_start(ap, errstr);
    vfprintf(stderr, errstr, ap);
    va_end(ap);
    exit(1);
  }
  
  void
  execsh(char *cmd, char **args)
  {
    char *sh, *prog, *arg;
    const struct passwd *pw;
  
    errno = 0;
    if ((pw = getpwuid(getuid())) == NULL) {
      if (errno)
        die("getpwuid: %s\n", strerror(errno));
      else
        die("who are you?\n");
    }
  
    if ((sh = getenv("SHELL")) == NULL)
      sh = (pw->pw_shell[0]) ? pw->pw_shell : cmd;
  
    if (args) {
      prog = args[0];
      arg = NULL;
    } else if (scroll) {
      prog = scroll;
      arg = utmp ? utmp : sh;
    } else if (utmp) {
      prog = utmp;
      arg = NULL;
    } else {
      prog = sh;
      arg = NULL;
    }
    DEFAULT(args, ((char *[]) {prog, arg, NULL}));
  
    unsetenv("COLUMNS");
    unsetenv("LINES");
    unsetenv("TERMCAP");
    setenv("LOGNAME", pw->pw_name, 1);
    setenv("USER", pw->pw_name, 1);
    setenv("SHELL", sh, 1);
    setenv("HOME", pw->pw_dir, 1);
    setenv("TERM", termname, 1);
  
    signal(SIGCHLD, SIG_DFL);
    signal(SIGHUP, SIG_DFL);
    signal(SIGINT, SIG_DFL);
    signal(SIGQUIT, SIG_DFL);
    signal(SIGTERM, SIG_DFL);
    signal(SIGALRM, SIG_DFL);
  
    execvp(prog, args);
    _exit(1);
  }
  
  void
  sigchld(int a)
  {
    int stat;
    pid_t p;
  
    if ((p = waitpid(pid, &stat, WNOHANG)) < 0)
      die("waiting for pid %hd failed: %s\n", pid, strerror(errno));
  
    if (pid != p)
      return;
  
    if (WIFEXITED(stat) && WEXITSTATUS(stat))
      die("child exited with status %d\n", WEXITSTATUS(stat));
    else if (WIFSIGNALED(stat))
      die("child terminated due to signal %d\n", WTERMSIG(stat));
    _exit(0);
  }
  
  void
  stty(char **args)
  {
    char cmd[_POSIX_ARG_MAX], **p, *q, *s;
    size_t n, siz;
  
    if ((n = strlen(stty_args)) > sizeof(cmd)-1)
      die("incorrect stty parameters\n");
    memcpy(cmd, stty_args, n);
    q = cmd + n;
    siz = sizeof(cmd) - n;
    for (p = args; p && (s = *p); ++p) {
      if ((n = strlen(s)) > siz-1)
        die("stty parameter length too long\n");
      *q++ = ' ';
      memcpy(q, s, n);
      q += n;
      siz -= n + 1;
    }
    *q = '\0';
    if (system(cmd) != 0)
      perror("Couldn't call stty");
  }
  
  int
  ttynew(char *line, char *cmd, char *out, char **args)
  {
    int m, s;
  
    if (out) {
      term.mode |= MODE_PRINT;
      iofd = (!strcmp(out, "-")) ?
          1 : open(out, O_WRONLY | O_CREAT, 0666);
      if (iofd < 0) {
        fprintf(stderr, "Error opening %s:%s\n",
          out, strerror(errno));
      }
    }
  
    if (line) {
      if ((cmdfd = open(line, O_RDWR)) < 0)
        die("open line '%s' failed: %s\n",
            line, strerror(errno));
      dup2(cmdfd, 0);
      stty(args);
      return cmdfd;
    }
  
    /* seems to work fine on linux, openbsd and freebsd */
    if (openpty(&m, &s, NULL, NULL, NULL) < 0)
      die("openpty failed: %s\n", strerror(errno));
  
    switch (pid = fork()) {
    case -1:
      die("fork failed: %s\n", strerror(errno));
      break;
    case 0:
      close(iofd);
      setsid(); /* create a new process group */
      dup2(s, 0);
      dup2(s, 1);
      dup2(s, 2);
      if (ioctl(s, TIOCSCTTY, NULL) < 0)
        die("ioctl TIOCSCTTY failed: %s\n", strerror(errno));
      close(s);
      close(m);
  #ifdef __OpenBSD__
      if (pledge("stdio getpw proc exec", NULL) == -1)
        die("pledge\n");
  #endif
      execsh(cmd, args);
      break;
    default:
  #ifdef __OpenBSD__
      if (pledge("stdio rpath tty proc", NULL) == -1)
        die("pledge\n");
  #endif
      close(s);
      cmdfd = m;
      signal(SIGCHLD, sigchld);
      break;
    }
    return cmdfd;
  }
  
  static int twrite_aborted = 0;
  int ttyread_pending() { return twrite_aborted; }
  
  size_t
  ttyread(void)
  {
    static char buf[BUFSIZ];
    static int buflen = 0;
    int ret, written;
  
    /* append read bytes to unprocessed bytes */
    ret = twrite_aborted ? 1 : read(cmdfd, buf+buflen, LEN(buf)-buflen);
  
    switch (ret) {
    case 0:
      exit(0);
    case -1:
      die("couldn't read from shell: %s\n", strerror(errno));
    default:
      buflen += twrite_aborted ? 0 : ret;
      written = twrite(buf, buflen, 0);
      buflen -= written;
      /* keep any incomplete UTF-8 byte sequence for the next call */
      if (buflen > 0)
        memmove(buf, buf + written, buflen);
      return ret;
    }
  }
  
  void
  ttywrite(const char *s, size_t n, int may_echo)
  {
    const char *next;
  
    if (may_echo && IS_SET(MODE_ECHO))
      twrite(s, n, 1);
  
    if (!IS_SET(MODE_CRLF)) {
      ttywriteraw(s, n);
      return;
    }
  
    /* This is similar to how the kernel handles ONLCR for ttys */
    while (n > 0) {
      if (*s == '\r') {
        next = s + 1;
        ttywriteraw("\r\n", 2);
      } else {
        next = memchr(s, '\r', n);
        DEFAULT(next, s + n);
        ttywriteraw(s, next - s);
      }
      n -= next - s;
      s = next;
    }
  }
  
  void
  ttywriteraw(const char *s, size_t n)
  {
    fd_set wfd, rfd;
    ssize_t r;
    size_t lim = 256;
  
    /*
     * Remember that we are using a pty, which might be a modem line.
     * Writing too much will clog the line. That's why we are doing this
     * dance.
     * FIXME: Migrate the world to Plan 9.
     */
    while (n > 0) {
      FD_ZERO(&wfd);
      FD_ZERO(&rfd);
      FD_SET(cmdfd, &wfd);
      FD_SET(cmdfd, &rfd);
  
      /* Check if we can write. */
      if (pselect(cmdfd+1, &rfd, &wfd, NULL, NULL, NULL) < 0) {
        if (errno == EINTR)
          continue;
        die("select failed: %s\n", strerror(errno));
      }
      if (FD_ISSET(cmdfd, &wfd)) {
        /*
         * Only write the bytes written by ttywrite() or the
         * default of 256. This seems to be a reasonable value
         * for a serial line. Bigger values might clog the I/O.
         */
        if ((r = write(cmdfd, s, (n < lim)? n : lim)) < 0)
          goto write_error;
        if (r < n) {
          /*
           * We weren't able to write out everything.
           * This means the buffer is getting full
           * again. Empty it.
           */
          if (n < lim)
            lim = ttyread();
          n -= r;
          s += r;
        } else {
          /* All bytes have been written. */
          break;
        }
      }
      if (FD_ISSET(cmdfd, &rfd))
        lim = ttyread();
    }
    return;
  
  write_error:
    die("write error on tty: %s\n", strerror(errno));
  }
  
  void
  ttyresize(int tw, int th)
  {
    struct winsize w;
  
    w.ws_row = term.row;
    w.ws_col = term.col;
    w.ws_xpixel = tw;
    w.ws_ypixel = th;
    if (ioctl(cmdfd, TIOCSWINSZ, &w) < 0)
      fprintf(stderr, "Couldn't set window size: %s\n", strerror(errno));
  }
  
  void
  ttyhangup()
  {
    /* Send SIGHUP to shell */
    kill(pid, SIGHUP);
  }
  
  int
  tattrset(int attr)
  {
    int i, j;
  
    for (i = 0; i < term.row-1; i++) {
      for (j = 0; j < term.col-1; j++) {
        if (term.line[i][j].mode & attr)
          return 1;
      }
    }
  
    return 0;
  }
  
  void
  tsetdirt(int top, int bot)
  {
    int i;
  
    LIMIT(top, 0, term.row-1);
    LIMIT(bot, 0, term.row-1);
  
    for (i = top; i <= bot; i++)
      term.dirty[i] = 1;
  }
  
  void
  tsetdirtattr(int attr)
  {
    int i, j;
  
    for (i = 0; i < term.row-1; i++) {
      for (j = 0; j < term.col-1; j++) {
        if (term.line[i][j].mode & attr) {
          tsetdirt(i, i);
          break;
        }
      }
    }
  }
  
  void
  tfulldirt(void)
  {
    tsync_end();
    tsetdirt(0, term.row-1);
  }
  
  void
  tcursor(int mode)
  {
    static TCursor c[2];
    int alt = IS_SET(MODE_ALTSCREEN);
  
    if (mode == CURSOR_SAVE) {
      c[alt] = term.c;
    } else if (mode == CURSOR_LOAD) {
      term.c = c[alt];
      tmoveto(c[alt].x, c[alt].y);
    }
  }
  
  void
  treset(void)
  {
    uint i;
  
    term.c = (TCursor){{
      .mode = ATTR_NULL,
      .fg = defaultfg,
      .bg = defaultbg
    }, .x = 0, .y = 0, .state = CURSOR_DEFAULT};
  
    memset(term.tabs, 0, term.col * sizeof(*term.tabs));
    for (i = tabspaces; i < term.col; i += tabspaces)
      term.tabs[i] = 1;
    term.top = 0;
    term.bot = term.row - 1;
    term.mode = MODE_WRAP|MODE_UTF8;
    memset(term.trantbl, CS_USA, sizeof(term.trantbl));
    term.charset = 0;
  
    for (i = 0; i < 2; i++) {
      tmoveto(0, 0);
      tcursor(CURSOR_SAVE);
      tclearregion(0, 0, term.col-1, term.row-1);
      tswapscreen();
    }
  }
  
  void
  tnew(int col, int row)
  {
    term = (Term){ .c = { .attr = { .fg = defaultfg, .bg = defaultbg } } };
    tresize(col, row);
    treset();
  }
  
  void
  tswapscreen(void)
  {
    Line *tmp = term.line;
  
    term.line = term.alt;
    term.alt = tmp;
    term.mode ^= MODE_ALTSCREEN;
    tfulldirt();
  }
  
  void
  tscrolldown(int orig, int n)
  {
    int i;
    Line temp;
  
    LIMIT(n, 0, term.bot-orig+1);
  
    tsetdirt(orig, term.bot-n);
    tclearregion(0, term.bot-n+1, term.col-1, term.bot);
  
    for (i = term.bot; i >= orig+n; i--) {
      temp = term.line[i];
      term.line[i] = term.line[i-n];
      term.line[i-n] = temp;
    }
  
    selscroll(orig, n);
  }
  
  void
  tscrollup(int orig, int n)
  {
    int i;
    Line temp;
  
    LIMIT(n, 0, term.bot-orig+1);
  
    tclearregion(0, orig, term.col-1, orig+n-1);
    tsetdirt(orig+n, term.bot);
  
    for (i = orig; i <= term.bot-n; i++) {
      temp = term.line[i];
      term.line[i] = term.line[i+n];
      term.line[i+n] = temp;
    }
  
    selscroll(orig, -n);
  }
  
  void
  selscroll(int orig, int n)
  {
    if (sel.ob.x == -1)
      return;
  
    if (BETWEEN(sel.nb.y, orig, term.bot) != BETWEEN(sel.ne.y, orig, term.bot)) {
      selclear();
    } else if (BETWEEN(sel.nb.y, orig, term.bot)) {
      sel.ob.y += n;
      sel.oe.y += n;
      if (sel.ob.y < term.top || sel.ob.y > term.bot ||
          sel.oe.y < term.top || sel.oe.y > term.bot) {
        selclear();
      } else {
        selnormalize();
      }
    }
  }
  
  void
  tnewline(int first_col)
  {
    int y = term.c.y;
  
    if (y == term.bot) {
      tscrollup(term.top, 1);
    } else {
      y++;
    }
    tmoveto(first_col ? 0 : term.c.x, y);
  }
  
  void
  csiparse(void)
  {
    char *p = csiescseq.buf, *np;
    long int v;
  
    csiescseq.narg = 0;
    if (*p == '?') {
      csiescseq.priv = 1;
      p++;
    }
  
    csiescseq.buf[csiescseq.len] = '\0';
    while (p < csiescseq.buf+csiescseq.len) {
      np = NULL;
      v = strtol(p, &np, 10);
      if (np == p)
        v = 0;
      if (v == LONG_MAX || v == LONG_MIN)
        v = -1;
      csiescseq.arg[csiescseq.narg++] = v;
      p = np;
      if (*p != ';' || csiescseq.narg == ESC_ARG_SIZ)
        break;
      p++;
    }
    csiescseq.mode[0] = *p++;
    csiescseq.mode[1] = (p < csiescseq.buf+csiescseq.len) ? *p : '\0';
  }
  
  /* for absolute user moves, when decom is set */
  void
  tmoveato(int x, int y)
  {
    tmoveto(x, y + ((term.c.state & CURSOR_ORIGIN) ? term.top: 0));
  }
  
  void
  tmoveto(int x, int y)
  {
    int miny, maxy;
  
    if (term.c.state & CURSOR_ORIGIN) {
      miny = term.top;
      maxy = term.bot;
    } else {
      miny = 0;
      maxy = term.row - 1;
    }
    term.c.state &= ~CURSOR_WRAPNEXT;
    term.c.x = LIMIT(x, 0, term.col-1);
    term.c.y = LIMIT(y, miny, maxy);
  }
  
  void
  tsetchar(Rune u, Glyph *attr, int x, int y)
  {
    static char *vt100_0[62] = { /* 0x41 - 0x7e */
      "↑", "↓", "→", "←", "█", "▚", "☃", /* A - G */
      0, 0, 0, 0, 0, 0, 0, 0, /* H - O */
      0, 0, 0, 0, 0, 0, 0, 0, /* P - W */
      0, 0, 0, 0, 0, 0, 0, " ", /* X - _ */
      "◆", "▒", "␉", "␌", "␍", "␊", "°", "±", /* ` - g */
      "␤", "␋", "┘", "┐", "┌", "└", "┼", "⎺", /* h - o */
      "⎻", "─", "⎼", "⎽", "├", "┤", "┴", "┬", /* p - w */
      "│", "≤", "≥", "π", "≠", "£", "·", /* x - ~ */
    };
  
    /*
     * The table is proudly stolen from rxvt.
     */
    if (term.trantbl[term.charset] == CS_GRAPHIC0 &&
       BETWEEN(u, 0x41, 0x7e) && vt100_0[u - 0x41])
      utf8decode(vt100_0[u - 0x41], &u, UTF_SIZ);
  
    if (term.line[y][x].mode & ATTR_WIDE) {
      if (x+1 < term.col) {
        term.line[y][x+1].u = ' ';
        term.line[y][x+1].mode &= ~ATTR_WDUMMY;
      }
    } else if (term.line[y][x].mode & ATTR_WDUMMY) {
      term.line[y][x-1].u = ' ';
      term.line[y][x-1].mode &= ~ATTR_WIDE;
    }
  
    term.dirty[y] = 1;
    term.line[y][x] = *attr;
    term.line[y][x].u = u;
  
    if (isboxdraw(u))
      term.line[y][x].mode |= ATTR_BOXDRAW;
  }
  
  void
  tclearregion(int x1, int y1, int x2, int y2)
  {
    int x, y, temp;
    Glyph *gp;
  
    if (x1 > x2)
      temp = x1, x1 = x2, x2 = temp;
    if (y1 > y2)
      temp = y1, y1 = y2, y2 = temp;
  
    LIMIT(x1, 0, term.col-1);
    LIMIT(x2, 0, term.col-1);
    LIMIT(y1, 0, term.row-1);
    LIMIT(y2, 0, term.row-1);
  
    for (y = y1; y <= y2; y++) {
      term.dirty[y] = 1;
      for (x = x1; x <= x2; x++) {
        gp = &term.line[y][x];
        if (selected(x, y))
          selclear();
        gp->fg = term.c.attr.fg;
        gp->bg = term.c.attr.bg;
        gp->mode = 0;
        gp->u = ' ';
      }
    }
  }
  
  void
  tdeletechar(int n)
  {
    int dst, src, size;
    Glyph *line;
  
    LIMIT(n, 0, term.col - term.c.x);
  
    dst = term.c.x;
    src = term.c.x + n;
    size = term.col - src;
    line = term.line[term.c.y];
  
    memmove(&line[dst], &line[src], size * sizeof(Glyph));
    tclearregion(term.col-n, term.c.y, term.col-1, term.c.y);
  }
  
  void
  tinsertblank(int n)
  {
    int dst, src, size;
    Glyph *line;
  
    LIMIT(n, 0, term.col - term.c.x);
  
    dst = term.c.x + n;
    src = term.c.x;
    size = term.col - dst;
    line = term.line[term.c.y];
  
    memmove(&line[dst], &line[src], size * sizeof(Glyph));
    tclearregion(src, term.c.y, dst - 1, term.c.y);
  }
  
  void
  tinsertblankline(int n)
  {
    if (BETWEEN(term.c.y, term.top, term.bot))
      tscrolldown(term.c.y, n);
  }
  
  void
  tdeleteline(int n)
  {
    if (BETWEEN(term.c.y, term.top, term.bot))
      tscrollup(term.c.y, n);
  }
  
  int32_t
  tdefcolor(int *attr, int *npar, int l)
  {
    int32_t idx = -1;
    uint r, g, b;
  
    switch (attr[*npar + 1]) {
    case 2: /* direct color in RGB space */
      if (*npar + 4 >= l) {
        fprintf(stderr,
          "erresc(38): Incorrect number of parameters (%d)\n",
          *npar);
        break;
      }
      r = attr[*npar + 2];
      g = attr[*npar + 3];
      b = attr[*npar + 4];
      *npar += 4;
      if (!BETWEEN(r, 0, 255) || !BETWEEN(g, 0, 255) || !BETWEEN(b, 0, 255))
        fprintf(stderr, "erresc: bad rgb color (%u,%u,%u)\n",
          r, g, b);
      else
        idx = TRUECOLOR(r, g, b);
      break;
    case 5: /* indexed color */
      if (*npar + 2 >= l) {
        fprintf(stderr,
          "erresc(38): Incorrect number of parameters (%d)\n",
          *npar);
        break;
      }
      *npar += 2;
      if (!BETWEEN(attr[*npar], 0, 255))
        fprintf(stderr, "erresc: bad fgcolor %d\n", attr[*npar]);
      else
        idx = attr[*npar];
      break;
    case 0: /* implemented defined (only foreground) */
    case 1: /* transparent */
    case 3: /* direct color in CMY space */
    case 4: /* direct color in CMYK space */
    default:
      fprintf(stderr,
              "erresc(38): gfx attr %d unknown\n", attr[*npar]);
      break;
    }
  
    return idx;
  }
  
  void
  tsetattr(int *attr, int l)
  {
    int i;
    int32_t idx;
  
    for (i = 0; i < l; i++) {
      switch (attr[i]) {
      case 0:
        term.c.attr.mode &= ~(
          ATTR_BOLD       |
          ATTR_FAINT      |
          ATTR_ITALIC     |
          ATTR_UNDERLINE  |
          ATTR_BLINK      |
          ATTR_REVERSE    |
          ATTR_INVISIBLE  |
          ATTR_STRUCK     );
        term.c.attr.fg = defaultfg;
        term.c.attr.bg = defaultbg;
        break;
      case 1:
        term.c.attr.mode |= ATTR_BOLD;
        break;
      case 2:
        term.c.attr.mode |= ATTR_FAINT;
        break;
      case 3:
        term.c.attr.mode |= ATTR_ITALIC;
        break;
      case 4:
        term.c.attr.mode |= ATTR_UNDERLINE;
        break;
      case 5: /* slow blink */
        /* FALLTHROUGH */
      case 6: /* rapid blink */
        term.c.attr.mode |= ATTR_BLINK;
        break;
      case 7:
        term.c.attr.mode |= ATTR_REVERSE;
        break;
      case 8:
        term.c.attr.mode |= ATTR_INVISIBLE;
        break;
      case 9:
        term.c.attr.mode |= ATTR_STRUCK;
        break;
      case 22:
        term.c.attr.mode &= ~(ATTR_BOLD | ATTR_FAINT);
        break;
      case 23:
        term.c.attr.mode &= ~ATTR_ITALIC;
        break;
      case 24:
        term.c.attr.mode &= ~ATTR_UNDERLINE;
        break;
      case 25:
        term.c.attr.mode &= ~ATTR_BLINK;
        break;
      case 27:
        term.c.attr.mode &= ~ATTR_REVERSE;
        break;
      case 28:
        term.c.attr.mode &= ~ATTR_INVISIBLE;
        break;
      case 29:
        term.c.attr.mode &= ~ATTR_STRUCK;
        break;
      case 38:
        if ((idx = tdefcolor(attr, &i, l)) >= 0)
          term.c.attr.fg = idx;
        break;
      case 39:
        term.c.attr.fg = defaultfg;
        break;
      case 48:
        if ((idx = tdefcolor(attr, &i, l)) >= 0)
          term.c.attr.bg = idx;
        break;
      case 49:
        term.c.attr.bg = defaultbg;
        break;
      default:
        if (BETWEEN(attr[i], 30, 37)) {
          term.c.attr.fg = attr[i] - 30;
        } else if (BETWEEN(attr[i], 40, 47)) {
          term.c.attr.bg = attr[i] - 40;
        } else if (BETWEEN(attr[i], 90, 97)) {
          term.c.attr.fg = attr[i] - 90 + 8;
        } else if (BETWEEN(attr[i], 100, 107)) {
          term.c.attr.bg = attr[i] - 100 + 8;
        } else {
          fprintf(stderr,
            "erresc(default): gfx attr %d unknown\n",
            attr[i]);
          csidump();
        }
        break;
      }
    }
  }
  
  void
  tsetscroll(int t, int b)
  {
    int temp;
  
    LIMIT(t, 0, term.row-1);
    LIMIT(b, 0, term.row-1);
    if (t > b) {
      temp = t;
      t = b;
      b = temp;
    }
    term.top = t;
    term.bot = b;
  }
  
  void
  tsetmode(int priv, int set, int *args, int narg)
  {
    int alt, *lim;
  
    for (lim = args + narg; args < lim; ++args) {
      if (priv) {
        switch (*args) {
        case 1: /* DECCKM -- Cursor key */
          xsetmode(set, MODE_APPCURSOR);
          break;
        case 5: /* DECSCNM -- Reverse video */
          xsetmode(set, MODE_REVERSE);
          break;
        case 6: /* DECOM -- Origin */
          MODBIT(term.c.state, set, CURSOR_ORIGIN);
          tmoveato(0, 0);
          break;
        case 7: /* DECAWM -- Auto wrap */
          MODBIT(term.mode, set, MODE_WRAP);
          break;
        case 0:  /* Error (IGNORED) */
        case 2:  /* DECANM -- ANSI/VT52 (IGNORED) */
        case 3:  /* DECCOLM -- Column  (IGNORED) */
        case 4:  /* DECSCLM -- Scroll (IGNORED) */
        case 8:  /* DECARM -- Auto repeat (IGNORED) */
        case 18: /* DECPFF -- Printer feed (IGNORED) */
        case 19: /* DECPEX -- Printer extent (IGNORED) */
        case 42: /* DECNRCM -- National characters (IGNORED) */
        case 12: /* att610 -- Start blinking cursor (IGNORED) */
          break;
        case 25: /* DECTCEM -- Text Cursor Enable Mode */
          xsetmode(!set, MODE_HIDE);
          break;
        case 9:    /* X10 mouse compatibility mode */
          xsetpointermotion(0);
          xsetmode(0, MODE_MOUSE);
          xsetmode(set, MODE_MOUSEX10);
          break;
        case 1000: /* 1000: report button press */
          xsetpointermotion(0);
          xsetmode(0, MODE_MOUSE);
          xsetmode(set, MODE_MOUSEBTN);
          break;
        case 1002: /* 1002: report motion on button press */
          xsetpointermotion(0);
          xsetmode(0, MODE_MOUSE);
          xsetmode(set, MODE_MOUSEMOTION);
          break;
        case 1003: /* 1003: enable all mouse motions */
          xsetpointermotion(set);
          xsetmode(0, MODE_MOUSE);
          xsetmode(set, MODE_MOUSEMANY);
          break;
        case 1004: /* 1004: send focus events to tty */
          xsetmode(set, MODE_FOCUS);
          break;
        case 1006: /* 1006: extended reporting mode */
          xsetmode(set, MODE_MOUSESGR);
          break;
        case 1034:
          xsetmode(set, MODE_8BIT);
          break;
        case 1049: /* swap screen & set/restore cursor as xterm */
          if (!allowaltscreen)
            break;
          tcursor((set) ? CURSOR_SAVE : CURSOR_LOAD);
          /* FALLTHROUGH */
        case 47: /* swap screen */
        case 1047:
          if (!allowaltscreen)
            break;
          alt = IS_SET(MODE_ALTSCREEN);
          if (alt) {
            tclearregion(0, 0, term.col-1,
                term.row-1);
          }
          if (set ^ alt) /* set is always 1 or 0 */
            tswapscreen();
          if (*args != 1049)
            break;
          /* FALLTHROUGH */
        case 1048:
          tcursor((set) ? CURSOR_SAVE : CURSOR_LOAD);
          break;
        case 2004: /* 2004: bracketed paste mode */
          xsetmode(set, MODE_BRCKTPASTE);
          break;
        /* Not implemented mouse modes. See comments there. */
        case 1001: /* mouse highlight mode; can hang the
                terminal by design when implemented. */
        case 1005: /* UTF-8 mouse mode; will confuse
                applications not supporting UTF-8
                and luit. */
        case 1015: /* urxvt mangled mouse mode; incompatible
                and can be mistaken for other control
                codes. */
          break;
        default:
          fprintf(stderr,
            "erresc: unknown private set/reset mode %d\n",
            *args);
          break;
        }
      } else {
        switch (*args) {
        case 0:  /* Error (IGNORED) */
          break;
        case 2:
          xsetmode(set, MODE_KBDLOCK);
          break;
        case 4:  /* IRM -- Insertion-replacement */
          MODBIT(term.mode, set, MODE_INSERT);
          break;
        case 12: /* SRM -- Send/Receive */
          MODBIT(term.mode, !set, MODE_ECHO);
          break;
        case 20: /* LNM -- Linefeed/new line */
          MODBIT(term.mode, set, MODE_CRLF);
          break;
        default:
          fprintf(stderr,
            "erresc: unknown set/reset mode %d\n",
            *args);
          break;
        }
      }
    }
  }
  
  void
  csihandle(void)
  {
    char buf[40];
    int len;
  
    switch (csiescseq.mode[0]) {
    default:
    unknown:
      fprintf(stderr, "erresc: unknown csi ");
      csidump();
      /* die(""); */
      break;
    case '@': /* ICH -- Insert <n> blank char */
      DEFAULT(csiescseq.arg[0], 1);
      tinsertblank(csiescseq.arg[0]);
      break;
    case 'A': /* CUU -- Cursor <n> Up */
      DEFAULT(csiescseq.arg[0], 1);
      tmoveto(term.c.x, term.c.y-csiescseq.arg[0]);
      break;
    case 'B': /* CUD -- Cursor <n> Down */
    case 'e': /* VPR --Cursor <n> Down */
      DEFAULT(csiescseq.arg[0], 1);
      tmoveto(term.c.x, term.c.y+csiescseq.arg[0]);
      break;
    case 'i': /* MC -- Media Copy */
      switch (csiescseq.arg[0]) {
      case 0:
        tdump();
        break;
      case 1:
        tdumpline(term.c.y);
        break;
      case 2:
        tdumpsel();
        break;
      case 4:
        term.mode &= ~MODE_PRINT;
        break;
      case 5:
        term.mode |= MODE_PRINT;
        break;
      }
      break;
    case 'c': /* DA -- Device Attributes */
      if (csiescseq.arg[0] == 0)
        ttywrite(vtiden, strlen(vtiden), 0);
      break;
    case 'b': /* REP -- if last char is printable print it <n> more times */
      DEFAULT(csiescseq.arg[0], 1);
      if (term.lastc)
        while (csiescseq.arg[0]-- > 0)
          tputc(term.lastc);
      break;
    case 'C': /* CUF -- Cursor <n> Forward */
    case 'a': /* HPR -- Cursor <n> Forward */
      DEFAULT(csiescseq.arg[0], 1);
      tmoveto(term.c.x+csiescseq.arg[0], term.c.y);
      break;
    case 'D': /* CUB -- Cursor <n> Backward */
      DEFAULT(csiescseq.arg[0], 1);
      tmoveto(term.c.x-csiescseq.arg[0], term.c.y);
      break;
    case 'E': /* CNL -- Cursor <n> Down and first col */
      DEFAULT(csiescseq.arg[0], 1);
      tmoveto(0, term.c.y+csiescseq.arg[0]);
      break;
    case 'F': /* CPL -- Cursor <n> Up and first col */
      DEFAULT(csiescseq.arg[0], 1);
      tmoveto(0, term.c.y-csiescseq.arg[0]);
      break;
    case 'g': /* TBC -- Tabulation clear */
      switch (csiescseq.arg[0]) {
      case 0: /* clear current tab stop */
        term.tabs[term.c.x] = 0;
        break;
      case 3: /* clear all the tabs */
        memset(term.tabs, 0, term.col * sizeof(*term.tabs));
        break;
      default:
        goto unknown;
      }
      break;
    case 'G': /* CHA -- Move to <col> */
    case '`': /* HPA */
      DEFAULT(csiescseq.arg[0], 1);
      tmoveto(csiescseq.arg[0]-1, term.c.y);
      break;
    case 'H': /* CUP -- Move to <row> <col> */
    case 'f': /* HVP */
      DEFAULT(csiescseq.arg[0], 1);
      DEFAULT(csiescseq.arg[1], 1);
      tmoveato(csiescseq.arg[1]-1, csiescseq.arg[0]-1);
      break;
    case 'I': /* CHT -- Cursor Forward Tabulation <n> tab stops */
      DEFAULT(csiescseq.arg[0], 1);
      tputtab(csiescseq.arg[0]);
      break;
    case 'J': /* ED -- Clear screen */
      switch (csiescseq.arg[0]) {
      case 0: /* below */
        tclearregion(term.c.x, term.c.y, term.col-1, term.c.y);
        if (term.c.y < term.row-1) {
          tclearregion(0, term.c.y+1, term.col-1,
              term.row-1);
        }
        break;
      case 1: /* above */
        if (term.c.y > 1)
          tclearregion(0, 0, term.col-1, term.c.y-1);
        tclearregion(0, term.c.y, term.c.x, term.c.y);
        break;
      case 2: /* all */
        tclearregion(0, 0, term.col-1, term.row-1);
        break;
      default:
        goto unknown;
      }
      break;
    case 'K': /* EL -- Clear line */
      switch (csiescseq.arg[0]) {
      case 0: /* right */
        tclearregion(term.c.x, term.c.y, term.col-1,
            term.c.y);
        break;
      case 1: /* left */
        tclearregion(0, term.c.y, term.c.x, term.c.y);
        break;
      case 2: /* all */
        tclearregion(0, term.c.y, term.col-1, term.c.y);
        break;
      }
      break;
    case 'S': /* SU -- Scroll <n> line up */
      DEFAULT(csiescseq.arg[0], 1);
      tscrollup(term.top, csiescseq.arg[0]);
      break;
    case 'T': /* SD -- Scroll <n> line down */
      DEFAULT(csiescseq.arg[0], 1);
      tscrolldown(term.top, csiescseq.arg[0]);
      break;
    case 'L': /* IL -- Insert <n> blank lines */
      DEFAULT(csiescseq.arg[0], 1);
      tinsertblankline(csiescseq.arg[0]);
      break;
    case 'l': /* RM -- Reset Mode */
      tsetmode(csiescseq.priv, 0, csiescseq.arg, csiescseq.narg);
      break;
    case 'M': /* DL -- Delete <n> lines */
      DEFAULT(csiescseq.arg[0], 1);
      tdeleteline(csiescseq.arg[0]);
      break;
    case 'X': /* ECH -- Erase <n> char */
      DEFAULT(csiescseq.arg[0], 1);
      tclearregion(term.c.x, term.c.y,
          term.c.x + csiescseq.arg[0] - 1, term.c.y);
      break;
    case 'P': /* DCH -- Delete <n> char */
      DEFAULT(csiescseq.arg[0], 1);
      tdeletechar(csiescseq.arg[0]);
      break;
    case 'Z': /* CBT -- Cursor Backward Tabulation <n> tab stops */
      DEFAULT(csiescseq.arg[0], 1);
      tputtab(-csiescseq.arg[0]);
      break;
    case 'd': /* VPA -- Move to <row> */
      DEFAULT(csiescseq.arg[0], 1);
      tmoveato(term.c.x, csiescseq.arg[0]-1);
      break;
    case 'h': /* SM -- Set terminal mode */
      tsetmode(csiescseq.priv, 1, csiescseq.arg, csiescseq.narg);
      break;
    case 'm': /* SGR -- Terminal attribute (color) */
      tsetattr(csiescseq.arg, csiescseq.narg);
      break;
    case 'n': /* DSR – Device Status Report (cursor position) */
      if (csiescseq.arg[0] == 6) {
        len = snprintf(buf, sizeof(buf), "\033[%i;%iR",
            term.c.y+1, term.c.x+1);
        ttywrite(buf, len, 0);
      }
      break;
    case 'r': /* DECSTBM -- Set Scrolling Region */
      if (csiescseq.priv) {
        goto unknown;
      } else {
        DEFAULT(csiescseq.arg[0], 1);
        DEFAULT(csiescseq.arg[1], term.row);
        tsetscroll(csiescseq.arg[0]-1, csiescseq.arg[1]-1);
        tmoveato(0, 0);
      }
      break;
    case 's': /* DECSC -- Save cursor position (ANSI.SYS) */
      tcursor(CURSOR_SAVE);
      break;
    case 'u': /* DECRC -- Restore cursor position (ANSI.SYS) */
      tcursor(CURSOR_LOAD);
      break;
    case ' ':
      switch (csiescseq.mode[1]) {
      case 'q': /* DECSCUSR -- Set Cursor Style */
        if (xsetcursor(csiescseq.arg[0]))
          goto unknown;
        break;
      default:
        goto unknown;
      }
      break;
    }
  }
  
  void
  csidump(void)
  {
    size_t i;
    uint c;
  
    fprintf(stderr, "ESC[");
    for (i = 0; i < csiescseq.len; i++) {
      c = csiescseq.buf[i] & 0xff;
      if (isprint(c)) {
        putc(c, stderr);
      } else if (c == '\n') {
        fprintf(stderr, "(\\n)");
      } else if (c == '\r') {
        fprintf(stderr, "(\\r)");
      } else if (c == 0x1b) {
        fprintf(stderr, "(\\e)");
      } else {
        fprintf(stderr, "(%02x)", c);
      }
    }
    putc('\n', stderr);
  }
  
  void
  csireset(void)
  {
    memset(&csiescseq, 0, sizeof(csiescseq));
  }
  
  void
  strhandle(void)
  {
    char *p = NULL, *dec;
    int j, narg, par;
  
    term.esc &= ~(ESC_STR_END|ESC_STR);
    strparse();
    par = (narg = strescseq.narg) ? atoi(strescseq.args[0]) : 0;
  
    switch (strescseq.type) {
    case ']': /* OSC -- Operating System Command */
      switch (par) {
      case 0:
        if (narg > 1) {
          xsettitle(strescseq.args[1]);
          xseticontitle(strescseq.args[1]);
        }
        return;
      case 1:
        if (narg > 1)
          xseticontitle(strescseq.args[1]);
        return;
      case 2:
        if (narg > 1)
          xsettitle(strescseq.args[1]);
        return;
      case 52:
        if (narg > 2 && allowwindowops) {
          dec = base64dec(strescseq.args[2]);
          if (dec) {
            xsetsel(dec);
            xclipcopy();
          } else {
            fprintf(stderr, "erresc: invalid base64\n");
          }
        }
        return;
      case 4: /* color set */
        if (narg < 3)
          break;
        p = strescseq.args[2];
        /* FALLTHROUGH */
      case 104: /* color reset, here p = NULL */
        j = (narg > 1) ? atoi(strescseq.args[1]) : -1;
        if (xsetcolorname(j, p)) {
          if (par == 104 && narg <= 1)
            return; /* color reset without parameter */
          fprintf(stderr, "erresc: invalid color j=%d, p=%s\n",
                  j, p ? p : "(null)");
        } else {
          /*
           * TODO if defaultbg color is changed, borders
           * are dirty
           */
          redraw();
        }
        return;
      }
      break;
    case 'k': /* old title set compatibility */
      xsettitle(strescseq.args[0]);
      return;
    case 'P': /* DCS -- Device Control String */
      /* https://gitlab.com/gnachman/iterm2/-/wikis/synchronized-updates-spec */
      if (strstr(strescseq.buf, "=1s") == strescseq.buf)
        tsync_begin();  /* BSU */
      else if (strstr(strescseq.buf, "=2s") == strescseq.buf)
        tsync_end();  /* ESU */
      return;
    case '_': /* APC -- Application Program Command */
    case '^': /* PM -- Privacy Message */
      return;
    }
  
    fprintf(stderr, "erresc: unknown str ");
    strdump();
  }
  
  void
  strparse(void)
  {
    int c;
    char *p = strescseq.buf;
  
    strescseq.narg = 0;
    strescseq.buf[strescseq.len] = '\0';
  
    if (*p == '\0')
      return;
  
    while (strescseq.narg < STR_ARG_SIZ) {
      strescseq.args[strescseq.narg++] = p;
      while ((c = *p) != ';' && c != '\0')
        ++p;
      if (c == '\0')
        return;
      *p++ = '\0';
    }
  }
  
  void
  strdump(void)
  {
    size_t i;
    uint c;
  
    fprintf(stderr, "ESC%c", strescseq.type);
    for (i = 0; i < strescseq.len; i++) {
      c = strescseq.buf[i] & 0xff;
      if (c == '\0') {
        putc('\n', stderr);
        return;
      } else if (isprint(c)) {
        putc(c, stderr);
      } else if (c == '\n') {
        fprintf(stderr, "(\\n)");
      } else if (c == '\r') {
        fprintf(stderr, "(\\r)");
      } else if (c == 0x1b) {
        fprintf(stderr, "(\\e)");
      } else {
        fprintf(stderr, "(%02x)", c);
      }
    }
    fprintf(stderr, "ESC\\\n");
  }
  
  void
  strreset(void)
  {
    strescseq = (STREscape){
      .buf = xrealloc(strescseq.buf, STR_BUF_SIZ),
      .siz = STR_BUF_SIZ,
    };
  }
  
  void
  sendbreak(const Arg *arg)
  {
    if (tcsendbreak(cmdfd, 0))
      perror("Error sending break");
  }
  
  void
  tprinter(char *s, size_t len)
  {
    if (iofd != -1 && xwrite(iofd, s, len) < 0) {
      perror("Error writing to output file");
      close(iofd);
      iofd = -1;
    }
  }
  
  void
  toggleprinter(const Arg *arg)
  {
    term.mode ^= MODE_PRINT;
  }
  
  void
  printscreen(const Arg *arg)
  {
    tdump();
  }
  
  void
  printsel(const Arg *arg)
  {
    tdumpsel();
  }
  
  void
  tdumpsel(void)
  {
    char *ptr;
  
    if ((ptr = getsel())) {
      tprinter(ptr, strlen(ptr));
      free(ptr);
    }
  }
  
  void
  tdumpline(int n)
  {
    char buf[UTF_SIZ];
    Glyph *bp, *end;
  
    bp = &term.line[n][0];
    end = &bp[MIN(tlinelen(n), term.col) - 1];
    if (bp != end || bp->u != ' ') {
      for ( ; bp <= end; ++bp)
        tprinter(buf, utf8encode(bp->u, buf));
    }
    tprinter("\n", 1);
  }
  
  void
  tdump(void)
  {
    int i;
  
    for (i = 0; i < term.row; ++i)
      tdumpline(i);
  }
  
  void
  tputtab(int n)
  {
    uint x = term.c.x;
  
    if (n > 0) {
      while (x < term.col && n--)
        for (++x; x < term.col && !term.tabs[x]; ++x)
          /* nothing */ ;
    } else if (n < 0) {
      while (x > 0 && n++)
        for (--x; x > 0 && !term.tabs[x]; --x)
          /* nothing */ ;
    }
    term.c.x = LIMIT(x, 0, term.col-1);
  }
  
  void
  tdefutf8(char ascii)
  {
    if (ascii == 'G')
      term.mode |= MODE_UTF8;
    else if (ascii == '@')
      term.mode &= ~MODE_UTF8;
  }
  
  void
  tdeftran(char ascii)
  {
    static char cs[] = "0B";
    static int vcs[] = {CS_GRAPHIC0, CS_USA};
    char *p;
  
    if ((p = strchr(cs, ascii)) == NULL) {
      fprintf(stderr, "esc unhandled charset: ESC ( %c\n", ascii);
    } else {
      term.trantbl[term.icharset] = vcs[p - cs];
    }
  }
  
  void
  tdectest(char c)
  {
    int x, y;
  
    if (c == '8') { /* DEC screen alignment test. */
      for (x = 0; x < term.col; ++x) {
        for (y = 0; y < term.row; ++y)
          tsetchar('E', &term.c.attr, x, y);
      }
    }
  }
  
  void
  tstrsequence(uchar c)
  {
    switch (c) {
    case 0x90:   /* DCS -- Device Control String */
      c = 'P';
      break;
    case 0x9f:   /* APC -- Application Program Command */
      c = '_';
      break;
    case 0x9e:   /* PM -- Privacy Message */
      c = '^';
      break;
    case 0x9d:   /* OSC -- Operating System Command */
      c = ']';
      break;
    }
    strreset();
    strescseq.type = c;
    term.esc |= ESC_STR;
  }
  
  void
  tcontrolcode(uchar ascii)
  {
    switch (ascii) {
    case '\t':   /* HT */
      tputtab(1);
      return;
    case '\b':   /* BS */
      tmoveto(term.c.x-1, term.c.y);
      return;
    case '\r':   /* CR */
      tmoveto(0, term.c.y);
      return;
    case '\f':   /* LF */
    case '\v':   /* VT */
    case '\n':   /* LF */
      /* go to first col if the mode is set */
      tnewline(IS_SET(MODE_CRLF));
      return;
    case '\a':   /* BEL */
      if (term.esc & ESC_STR_END) {
        /* backwards compatibility to xterm */
        strhandle();
      } else {
        xbell();
      }
      break;
    case '\033': /* ESC */
      csireset();
      term.esc &= ~(ESC_CSI|ESC_ALTCHARSET|ESC_TEST);
      term.esc |= ESC_START;
      return;
    case '\016': /* SO (LS1 -- Locking shift 1) */
    case '\017': /* SI (LS0 -- Locking shift 0) */
      term.charset = 1 - (ascii - '\016');
      return;
    case '\032': /* SUB */
      tsetchar('?', &term.c.attr, term.c.x, term.c.y);
      /* FALLTHROUGH */
    case '\030': /* CAN */
      csireset();
      break;
    case '\005': /* ENQ (IGNORED) */
    case '\000': /* NUL (IGNORED) */
    case '\021': /* XON (IGNORED) */
    case '\023': /* XOFF (IGNORED) */
    case 0177:   /* DEL (IGNORED) */
      return;
    case 0x80:   /* TODO: PAD */
    case 0x81:   /* TODO: HOP */
    case 0x82:   /* TODO: BPH */
    case 0x83:   /* TODO: NBH */
    case 0x84:   /* TODO: IND */
      break;
    case 0x85:   /* NEL -- Next line */
      tnewline(1); /* always go to first col */
      break;
    case 0x86:   /* TODO: SSA */
    case 0x87:   /* TODO: ESA */
      break;
    case 0x88:   /* HTS -- Horizontal tab stop */
      term.tabs[term.c.x] = 1;
      break;
    case 0x89:   /* TODO: HTJ */
    case 0x8a:   /* TODO: VTS */
    case 0x8b:   /* TODO: PLD */
    case 0x8c:   /* TODO: PLU */
    case 0x8d:   /* TODO: RI */
    case 0x8e:   /* TODO: SS2 */
    case 0x8f:   /* TODO: SS3 */
    case 0x91:   /* TODO: PU1 */
    case 0x92:   /* TODO: PU2 */
    case 0x93:   /* TODO: STS */
    case 0x94:   /* TODO: CCH */
    case 0x95:   /* TODO: MW */
    case 0x96:   /* TODO: SPA */
    case 0x97:   /* TODO: EPA */
    case 0x98:   /* TODO: SOS */
    case 0x99:   /* TODO: SGCI */
      break;
    case 0x9a:   /* DECID -- Identify Terminal */
      ttywrite(vtiden, strlen(vtiden), 0);
      break;
    case 0x9b:   /* TODO: CSI */
    case 0x9c:   /* TODO: ST */
      break;
    case 0x90:   /* DCS -- Device Control String */
    case 0x9d:   /* OSC -- Operating System Command */
    case 0x9e:   /* PM -- Privacy Message */
    case 0x9f:   /* APC -- Application Program Command */
      tstrsequence(ascii);
      return;
    }
    /* only CAN, SUB, \a and C1 chars interrupt a sequence */
    term.esc &= ~(ESC_STR_END|ESC_STR);
  }
  
  /*
   * returns 1 when the sequence is finished and it hasn't to read
   * more characters for this sequence, otherwise 0
   */
  int
  eschandle(uchar ascii)
  {
    switch (ascii) {
    case '[':
      term.esc |= ESC_CSI;
      return 0;
    case '#':
      term.esc |= ESC_TEST;
      return 0;
    case '%':
      term.esc |= ESC_UTF8;
      return 0;
    case 'P': /* DCS -- Device Control String */
    case '_': /* APC -- Application Program Command */
    case '^': /* PM -- Privacy Message */
    case ']': /* OSC -- Operating System Command */
    case 'k': /* old title set compatibility */
      tstrsequence(ascii);
      return 0;
    case 'n': /* LS2 -- Locking shift 2 */
    case 'o': /* LS3 -- Locking shift 3 */
      term.charset = 2 + (ascii - 'n');
      break;
    case '(': /* GZD4 -- set primary charset G0 */
    case ')': /* G1D4 -- set secondary charset G1 */
    case '*': /* G2D4 -- set tertiary charset G2 */
    case '+': /* G3D4 -- set quaternary charset G3 */
      term.icharset = ascii - '(';
      term.esc |= ESC_ALTCHARSET;
      return 0;
    case 'D': /* IND -- Linefeed */
      if (term.c.y == term.bot) {
        tscrollup(term.top, 1);
      } else {
        tmoveto(term.c.x, term.c.y+1);
      }
      break;
    case 'E': /* NEL -- Next line */
      tnewline(1); /* always go to first col */
      break;
    case 'H': /* HTS -- Horizontal tab stop */
      term.tabs[term.c.x] = 1;
      break;
    case 'M': /* RI -- Reverse index */
      if (term.c.y == term.top) {
        tscrolldown(term.top, 1);
      } else {
        tmoveto(term.c.x, term.c.y-1);
      }
      break;
    case 'Z': /* DECID -- Identify Terminal */
      ttywrite(vtiden, strlen(vtiden), 0);
      break;
    case 'c': /* RIS -- Reset to initial state */
      treset();
      resettitle();
      xloadcols();
      break;
    case '=': /* DECPAM -- Application keypad */
      xsetmode(1, MODE_APPKEYPAD);
      break;
    case '>': /* DECPNM -- Normal keypad */
      xsetmode(0, MODE_APPKEYPAD);
      break;
    case '7': /* DECSC -- Save Cursor */
      tcursor(CURSOR_SAVE);
      break;
    case '8': /* DECRC -- Restore Cursor */
      tcursor(CURSOR_LOAD);
      break;
    case '\\': /* ST -- String Terminator */
      if (term.esc & ESC_STR_END)
        strhandle();
      break;
    default:
      fprintf(stderr, "erresc: unknown sequence ESC 0x%02X '%c'\n",
        (uchar) ascii, isprint(ascii)? ascii:'.');
      break;
    }
    return 1;
  }
  
  void
  tputc(Rune u)
  {
    char c[UTF_SIZ];
    int control;
    int width, len;
    Glyph *gp;
  
    control = ISCONTROL(u);
    if (u < 127 || !IS_SET(MODE_UTF8)) {
      c[0] = u;
      width = len = 1;
    } else {
      len = utf8encode(u, c);
      if (!control && (width = wcwidth(u)) == -1)
        width = 1;
    }
  
    if (IS_SET(MODE_PRINT))
      tprinter(c, len);
  
    /*
     * STR sequence must be checked before anything else
     * because it uses all following characters until it
     * receives a ESC, a SUB, a ST or any other C1 control
     * character.
     */
    if (term.esc & ESC_STR) {
      if (u == '\a' || u == 030 || u == 032 || u == 033 ||
         ISCONTROLC1(u)) {
        term.esc &= ~(ESC_START|ESC_STR);
        term.esc |= ESC_STR_END;
        goto check_control_code;
      }
  
      if (strescseq.len+len >= strescseq.siz) {
        /*
         * Here is a bug in terminals. If the user never sends
         * some code to stop the str or esc command, then st
         * will stop responding. But this is better than
         * silently failing with unknown characters. At least
         * then users will report back.
         *
         * In the case users ever get fixed, here is the code:
         */
        /*
         * term.esc = 0;
         * strhandle();
         */
        if (strescseq.siz > (SIZE_MAX - UTF_SIZ) / 2)
          return;
        strescseq.siz *= 2;
        strescseq.buf = xrealloc(strescseq.buf, strescseq.siz);
      }
  
      memmove(&strescseq.buf[strescseq.len], c, len);
      strescseq.len += len;
      return;
    }
  
  check_control_code:
    /*
     * Actions of control codes must be performed as soon they arrive
     * because they can be embedded inside a control sequence, and
     * they must not cause conflicts with sequences.
     */
    if (control) {
      tcontrolcode(u);
      /*
       * control codes are not shown ever
       */
      if (!term.esc)
        term.lastc = 0;
      return;
    } else if (term.esc & ESC_START) {
      if (term.esc & ESC_CSI) {
        csiescseq.buf[csiescseq.len++] = u;
        if (BETWEEN(u, 0x40, 0x7E)
            || csiescseq.len >= \
            sizeof(csiescseq.buf)-1) {
          term.esc = 0;
          csiparse();
          csihandle();
        }
        return;
      } else if (term.esc & ESC_UTF8) {
        tdefutf8(u);
      } else if (term.esc & ESC_ALTCHARSET) {
        tdeftran(u);
      } else if (term.esc & ESC_TEST) {
        tdectest(u);
      } else {
        if (!eschandle(u))
          return;
        /* sequence already finished */
      }
      term.esc = 0;
      /*
       * All characters which form part of a sequence are not
       * printed
       */
      return;
    }
    if (selected(term.c.x, term.c.y))
      selclear();
  
    gp = &term.line[term.c.y][term.c.x];
    if (IS_SET(MODE_WRAP) && (term.c.state & CURSOR_WRAPNEXT)) {
      gp->mode |= ATTR_WRAP;
      tnewline(1);
      gp = &term.line[term.c.y][term.c.x];
    }
  
    if (IS_SET(MODE_INSERT) && term.c.x+width < term.col)
      memmove(gp+width, gp, (term.col - term.c.x - width) * sizeof(Glyph));
  
    if (term.c.x+width > term.col) {
      tnewline(1);
      gp = &term.line[term.c.y][term.c.x];
    }
  
    tsetchar(u, &term.c.attr, term.c.x, term.c.y);
    term.lastc = u;
  
    if (width == 2) {
      gp->mode |= ATTR_WIDE;
      if (term.c.x+1 < term.col) {
        gp[1].u = '\0';
        gp[1].mode = ATTR_WDUMMY;
      }
    }
    if (term.c.x+width < term.col) {
      tmoveto(term.c.x+width, term.c.y);
    } else {
      term.c.state |= CURSOR_WRAPNEXT;
    }
  }
  
  int
  twrite(const char *buf, int buflen, int show_ctrl)
  {
    int charsize;
    Rune u;
    int n;
  
    int su0 = su;
    twrite_aborted = 0;
  
    for (n = 0; n < buflen; n += charsize) {
      if (IS_SET(MODE_UTF8)) {
        /* process a complete utf8 char */
        charsize = utf8decode(buf + n, &u, buflen - n);
        if (charsize == 0)
          break;
      } else {
        u = buf[n] & 0xFF;
        charsize = 1;
      }
      if (su0 && !su) {
        twrite_aborted = 1;
        break;  // ESU - allow rendering before a new BSU
      }
      if (show_ctrl && ISCONTROL(u)) {
        if (u & 0x80) {
          u &= 0x7f;
          tputc('^');
          tputc('[');
        } else if (u != '\n' && u != '\r' && u != '\t') {
          u ^= 0x40;
          tputc('^');
        }
      }
      tputc(u);
    }
    return n;
  }
  
  void
  tresize(int col, int row)
  {
    int i;
    int minrow = MIN(row, term.row);
    int mincol = MIN(col, term.col);
    int *bp;
    TCursor c;
  
    if (col < 1 || row < 1) {
      fprintf(stderr,
              "tresize: error resizing to %dx%d\n", col, row);
      return;
    }
  
    /*
     * slide screen to keep cursor where we expect it -
     * tscrollup would work here, but we can optimize to
     * memmove because we're freeing the earlier lines
     */
    for (i = 0; i <= term.c.y - row; i++) {
      free(term.line[i]);
      free(term.alt[i]);
    }
    /* ensure that both src and dst are not NULL */
    if (i > 0) {
      memmove(term.line, term.line + i, row * sizeof(Line));
      memmove(term.alt, term.alt + i, row * sizeof(Line));
    }
    for (i += row; i < term.row; i++) {
      free(term.line[i]);
      free(term.alt[i]);
    }
  
    /* resize to new height */
    term.line = xrealloc(term.line, row * sizeof(Line));
    term.alt  = xrealloc(term.alt,  row * sizeof(Line));
    term.dirty = xrealloc(term.dirty, row * sizeof(*term.dirty));
    term.tabs = xrealloc(term.tabs, col * sizeof(*term.tabs));
  
    /* resize each row to new width, zero-pad if needed */
    for (i = 0; i < minrow; i++) {
      term.line[i] = xrealloc(term.line[i], col * sizeof(Glyph));
      term.alt[i]  = xrealloc(term.alt[i],  col * sizeof(Glyph));
    }
  
    /* allocate any new rows */
    for (/* i = minrow */; i < row; i++) {
      term.line[i] = xmalloc(col * sizeof(Glyph));
      term.alt[i] = xmalloc(col * sizeof(Glyph));
    }
    if (col > term.col) {
      bp = term.tabs + term.col;
  
      memset(bp, 0, sizeof(*term.tabs) * (col - term.col));
      while (--bp > term.tabs && !*bp)
        /* nothing */ ;
      for (bp += tabspaces; bp < term.tabs + col; bp += tabspaces)
        *bp = 1;
    }
    /* update terminal size */
    term.col = col;
    term.row = row;
    /* reset scrolling region */
    tsetscroll(0, row-1);
    /* make use of the LIMIT in tmoveto */
    tmoveto(term.c.x, term.c.y);
    /* Clearing both screens (it makes dirty all lines) */
    c = term.c;
    for (i = 0; i < 2; i++) {
      if (mincol < col && 0 < minrow) {
        tclearregion(mincol, 0, col - 1, minrow - 1);
      }
      if (0 < col && minrow < row) {
        tclearregion(0, minrow, col - 1, row - 1);
      }
      tswapscreen();
      tcursor(CURSOR_LOAD);
    }
    term.c = c;
  }
  
  void
  resettitle(void)
  {
    xsettitle(NULL);
  }
  
  void
  drawregion(int x1, int y1, int x2, int y2)
  {
    int y;
  
    for (y = y1; y < y2; y++) {
      if (!term.dirty[y])
        continue;
  
      term.dirty[y] = 0;
      xdrawline(term.line[y], x1, y, x2);
    }
  }
  
  void
  draw(void)
  {
    int cx = term.c.x, ocx = term.ocx, ocy = term.ocy;
  
    if (!xstartdraw())
      return;
  
    /* adjust cursor position */
    LIMIT(term.ocx, 0, term.col-1);
    LIMIT(term.ocy, 0, term.row-1);
    if (term.line[term.ocy][term.ocx].mode & ATTR_WDUMMY)
      term.ocx--;
    if (term.line[term.c.y][cx].mode & ATTR_WDUMMY)
      cx--;
  
    drawregion(0, 0, term.col, term.row);
    xdrawcursor(cx, term.c.y, term.line[term.c.y][cx],
        term.ocx, term.ocy, term.line[term.ocy][term.ocx],
        term.line[term.ocy], term.col);
    term.ocx = cx;
    term.ocy = term.c.y;
    xfinishdraw();
    if (ocx != term.ocx || ocy != term.ocy)
      xximspot(term.ocx, term.ocy);
  }
  
  void
  redraw(void)
  {
    tfulldirt();
    draw();
  }
  
  