scsh-0.5/scsh/regexp/regsub.c

84 lines
2.1 KiB
C

/*
* regsub @(#)regsub.c 1.3 of 2 April 86
*
* Copyright (c) 1986 by University of Toronto. Written by Henry Spencer. Not
* derived from licensed software.
*
* Permission is granted to anyone to use this software for any purpose on any
* computer system, and to redistribute it freely, subject to the following
* restrictions:
*
* 1. The author is not responsible for the consequences of use of this
* software, no matter how awful, even if they arise from defects in it.
*
* 2. The origin of this software must not be misrepresented, either by explicit
* claim or by omission.
*
* 3. Altered versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
*/
#include <stdio.h>
#ifdef AMIGA
#include "regexp.h"
#else
#include <regexp.h>
#endif
#include "regmagic.h"
#ifndef CHARBITS
#define UCHARAT(p) ((int)*(unsigned char *)(p))
#else
#define UCHARAT(p) ((int)*(p)&CHARBITS)
#endif
/*
* - regsub - perform substitutions after a regexp match
*/
void
regsub(prog, source, dest)
regexp *prog;
char *source;
char *dest;
{
register char *src;
register char *dst;
register char c;
register int no;
register int len;
extern char *strncpy();
if (prog == NULL || source == NULL || dest == NULL) {
regerror("NULL parm to regsub");
return;
}
if (UCHARAT(prog->program) != MAGIC) {
regerror("damaged regexp fed to regsub");
return;
}
src = source;
dst = dest;
while ((c = *src++) != '\0') {
if (c == '&')
no = 0;
else if (c == '\\' && '0' <= *src && *src <= '9')
no = *src++ - '0';
else
no = -1;
if (no < 0) { /* Ordinary character. */
if (c == '\\' && (*src == '\\' || *src == '&'))
c = *src++;
*dst++ = c;
} else if (prog->startp[no] != NULL && prog->endp[no] != NULL) {
len = prog->endp[no] - prog->startp[no];
(void) strncpy(dst, prog->startp[no], len);
dst += len;
if (len != 0 && *(dst - 1) == '\0') { /* strncpy hit NUL. */
regerror("damaged match string");
return;
}
}
}
*dst++ = '\0';
}