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