/* * 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. *//* This is an altered version.  It has been modified by David   Huggins-Daines <dhd@cepstral.com> on 2001-10-23 to use a different   API and be re-entrant and safe and all that good stuff. */#include "cst_regex.h"#include "cst_string.h"#include "cst_error.h" size_t cst_regsub(const cst_regstate *state, const char *in, char *out, size_t max){	const char *src;	char *dst;	int c, no, len;	size_t count; 	if (state == NULL || in == NULL) {		cst_errmsg("NULL parm to regsub\n");		cst_error();	} 	src = in;	dst = out;	count = 0;	while ((c = *src++) != '\0') {		if (out && dst + 1 > out + max - 1)			break;		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++;			if (out)				*dst++ = c;			count++; 		} else if (state->startp[no] != NULL && state->endp[no] != NULL) {			len = state->endp[no] - state->startp[no];			if (out) {				if (dst + len > out + max - 1)					len = (out + max - 1) - dst;				strncpy(dst, state->startp[no], len);				dst += len;				/* strncpy hit NUL. */				if (len != 0 && *(dst-1) == '\0') {					cst_errmsg("damaged match string");					cst_error();				}			}			count += len;		}	}	if (out && dst - out + 1 < (int)max)		*dst++ = '\0'; 	return count;}