text: /* sub.c: This file contains the substitution routines for the ed
     line editor */
  /*-
   * Copyright (c) 1993 Andrew Moore, Talke Studio.
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   *
   * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   *
   * @(#)sub.c,v 1.1 1994/02/01 00:34:44 alm Exp
   * $FreeBSD: head/bin/ed/sub.c 241720 2012-10-19 05:43:38Z ed $
   */
  
  #include "ed.h"
  
  
  static char *rhbuf;		/* rhs substitution buffer */
  static int rhbufsz;		/* rhs substitution buffer size */
  static int rhbufi;		/* rhs substitution buffer index */
  
  /* extract_subst_tail: extract substitution tail from the command buffer */
  int
  extract_subst_tail(int *flagp, long *np)
  {
  	char delimiter;
  
  	*flagp = *np = 0;
  	if ((delimiter = *ibufp) == '\n') {
  		rhbufi = 0;
  		*flagp = GPR;
  		return 0;
  	} else if (extract_subst_template() == NULL)
  		return  ERR;
  	else if (*ibufp == '\n') {
  		*flagp = GPR;
  		return 0;
  	} else if (*ibufp == delimiter)
  		ibufp++;
  	if ('1' <= *ibufp && *ibufp <= '9') {
  		STRTOL(*np, ibufp);
  		return 0;
  	} else if (*ibufp == 'g') {
  		ibufp++;
  		*flagp = GSG;
  		return 0;
  	}
  	return 0;
  }
  
  
  /* extract_subst_template: return pointer to copy of substitution template
     in the command buffer */
  char *
  extract_subst_template(void)
  {
  	int n = 0;
  	int i = 0;
  	char c;
  	char delimiter = *ibufp++;
  
  	if (*ibufp == '%' && *(ibufp + 1) == delimiter) {
  		ibufp++;
  		if (!rhbuf)
  			errmsg = "no previous substitution";
  		return rhbuf;
  	}
  	while (*ibufp != delimiter) {
  		REALLOC(rhbuf, rhbufsz, i + 2, NULL);
  		if ((c = rhbuf[i++] = *ibufp++) == '\n' && *ibufp == '\0') {
  			i--, ibufp--;
  			break;
  		} else if (c != '\\')
  			;
  		else if ((rhbuf[i++] = *ibufp++) != '\n')
  			;
  		else if (!isglobal) {
  			while ((n = get_tty_line()) == 0 ||
  			    (n > 0 && ibuf[n - 1] != '\n'))
  				clearerr(stdin);
  			if (n < 0)
  				return NULL;
  		}
  	}
  	REALLOC(rhbuf, rhbufsz, i + 1, NULL);
  	rhbuf[rhbufi = i] = '\0';
  	return  rhbuf;
  }
  
  
  static char *rbuf;		/* substitute_matching_text buffer */
  static int rbufsz;		/* substitute_matching_text buffer size */
  
  /* search_and_replace: for each line in a range, change text matching a pattern
     according to a substitution template; return status  */
  int
  search_and_replace(pattern_t *pat, int gflag, int kth)
  {
  	undo_t *up;
  	const char *txt;
  	const char *eot;
  	long lc;
  	long xa = current_addr;
  	int nsubs = 0;
  	line_t *lp;
  	int len;
  
  	current_addr = first_addr - 1;
  	for (lc = 0; lc <= second_addr - first_addr; lc++) {
  		lp = get_addressed_line_node(++current_addr);
  		if ((len = substitute_matching_text(pat, lp, gflag, kth)) < 0)
  			return ERR;
  		else if (len) {
  			up = NULL;
  			if (delete_lines(current_addr, current_addr) < 0)
  				return ERR;
  			txt = rbuf;
  			eot = rbuf + len;
  			SPL1();
  			do {
  				if ((txt = put_sbuf_line(txt)) == NULL) {
  					SPL0();
  					return ERR;
  				} else if (up)
  					up->t = get_addressed_line_node(current_addr);
  				else if ((up = push_undo_stack(UADD,
  				    current_addr, current_addr)) == NULL) {
  					SPL0();
  					return ERR;
  				}
  			} while (txt != eot);
  			SPL0();
  			nsubs++;
  			xa = current_addr;
  		}
  	}
  	current_addr = xa;
  	if  (nsubs == 0 && !(gflag & GLB)) {
  		errmsg = "no match";
  		return ERR;
  	} else if ((gflag & (GPR | GLS | GNP)) &&
  	    display_lines(current_addr, current_addr, gflag) < 0)
  		return ERR;
  	return 0;
  }
  
  
  /* substitute_matching_text: replace text matched by a pattern according to
     a substitution template; return pointer to the modified text */
  int
  substitute_matching_text(pattern_t *pat, line_t *lp, int gflag, int kth)
  {
  	int off = 0;
  	int changed = 0;
  	int matchno = 0;
  	int i = 0;
  	regmatch_t rm[SE_MAX];
  	char *txt;
  	char *eot;
  
  	if ((txt = get_sbuf_line(lp)) == NULL)
  		return ERR;
  	if (isbinary)
  		NUL_TO_NEWLINE(txt, lp->len);
  	eot = txt + lp->len;
  	if (!regexec(pat, txt, SE_MAX, rm, 0)) {
  		do {
  			if (!kth || kth == ++matchno) {
  				changed++;
  				i = rm[0].rm_so;
  				REALLOC(rbuf, rbufsz, off + i, ERR);
  				if (isbinary)
  					NEWLINE_TO_NUL(txt, rm[0].rm_eo);
  				memcpy(rbuf + off, txt, i);
  				off += i;
  				if ((off = apply_subst_template(txt, rm, off,
  				    pat->re_nsub)) < 0)
  					return ERR;
  			} else {
  				i = rm[0].rm_eo;
  				REALLOC(rbuf, rbufsz, off + i, ERR);
  				if (isbinary)
  					NEWLINE_TO_NUL(txt, i);
  				memcpy(rbuf + off, txt, i);
  				off += i;
  			}
  			txt += rm[0].rm_eo;
  		} while (*txt &&
                          (!changed || ((gflag & GSG) && rm[0].rm_eo)) &&
  		        !regexec(pat, txt, SE_MAX, rm, REG_NOTBOL));
  		i = eot - txt;
  		REALLOC(rbuf, rbufsz, off + i + 2, ERR);
  		if (i > 0 && !rm[0].rm_eo && (gflag & GSG)) {
  			errmsg = "infinite substitution loop";
  			return  ERR;
  		}
  		if (isbinary)
  			NEWLINE_TO_NUL(txt, i);
  		memcpy(rbuf + off, txt, i);
  		memcpy(rbuf + off + i, "\n", 2);
  	}
  	return changed ? off + i + 1 : 0;
  }
  
  
  /* apply_subst_template: modify text according to a substitution template;
     return offset to end of modified text */
  int
  apply_subst_template(const char *boln, regmatch_t *rm, int off, int re_nsub)
  {
  	int j = 0;
  	int k = 0;
  	int n;
  	char *sub = rhbuf;
  
  	for (; sub - rhbuf < rhbufi; sub++)
  		if (*sub == '&') {
  			j = rm[0].rm_so;
  			k = rm[0].rm_eo;
  			REALLOC(rbuf, rbufsz, off + k - j, ERR);
  			while (j < k)
  				rbuf[off++] = boln[j++];
  		} else if (*sub == '\\' && '1' <= *++sub && *sub <= '9' &&
  		    (n = *sub - '0') <= re_nsub) {
  			j = rm[n].rm_so;
  			k = rm[n].rm_eo;
  			REALLOC(rbuf, rbufsz, off + k - j, ERR);
  			while (j < k)
  				rbuf[off++] = boln[j++];
  		} else {
  			REALLOC(rbuf, rbufsz, off + 1, ERR);
  			rbuf[off++] = *sub;
  		}
  	REALLOC(rbuf, rbufsz, off + 1, ERR);
  	rbuf[off] = '\0';
  	return off;
  }
  