minix/lib/libc/other/v8regsub.c

90 lines
2.2 KiB
C

/* regsub
*
* 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 <string.h>
#include <stdio.h>
#define const /* avoid "const poisoning" */
#include <regexp.h>
#undef const
/* The first byte of the regexp internal "program" is actually this magic
* number; the start node begins in the second byte.
*/
#define MAGIC 0234
#define CHARBITS 0377
#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;
if (prog == (regexp *)NULL || source == (char *)NULL || dest == (char *)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] != (char *)NULL && prog->endp[no] != (char *)NULL) {
len = (int) (prog->endp[no] - prog->startp[no]);
strncpy(dst, prog->startp[no], len);
dst += len;
if (len != 0 && *(dst - 1) == '\0') { /* strncpy hit NUL. */
regerror("damaged match string");
return;
}
}
}
*dst++ = '\0';
}
/*
* $PchId: regsub.c,v 1.3 1995/11/27 20:18:16 philip Exp $
*/