regsub.c   [plain text]

/*
 * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * Portions Copyright (c) 1999 Apple Computer, Inc.  All Rights
 * Reserved.  This file contains Original Code and/or Modifications of
 * Original Code as defined in and that are subject to the Apple Public
 * Source License Version 1.1 (the "License").  You may not use this file
 * except in compliance with the License.  Please obtain a copy of the
 * License at http://www.apple.com/publicsource and read it before using
 * this file.
 * 
 * The Original Code and all software distributed under the License are
 * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE OR NON- INFRINGEMENT.  Please see the
 * License for the specific language governing rights and limitations
 * under the License.
 * 
 * @APPLE_LICENSE_HEADER_END@
 */
/*
 * 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 <regexp.h>
#include <stdio.h>
#include <string.h>
#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)
const regexp *prog;
const 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 = (char *)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';
}