/*-
 * Copyright (c)1997-2005 by Hartmut Brandt
 * 	All rights reserved.
 *
 * Author: Harti Brandt <harti@freebsd.org>
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 
 * THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * $Begemot: libbegemot/cstrc.c,v 1.5 2005/06/01 07:50:35 brandt_h Exp $
 */
# include <string.h>
# include <ctype.h>
# include "begemot.h"

# define GROW 100

int cstrwarn;

static unsigned char getx(char **);
static unsigned char geto(char **);

char *
cstrc(char **pp, char delim, size_t *plen)
{
	size_t alloc;
	char *str;
	unsigned char c;

	alloc = GROW;
	*plen = 0;
	str = xalloc(alloc);

	while((c = **pp) != (unsigned char)delim && c != '\0') {
		(*pp)++;
		if(c == '\\') {
			switch(c = *(*pp)++) {

			  case '\0':
				(*pp)--;
				c = '\\';
				break;

			  case '\\':
			  case '\'':
			  case '"':
				break;

			  default:
				if(cstrwarn)
					warn("unknown escape sequence '%c'", c);
				break;

			  case 'a':
				c = '\a';
				break;

			  case 'b':
				c = '\b';
				break;

			  case 'f':
				c = '\f';
				break;

			  case 'n':
				c = '\n';
				break;

			  case 'r':
				c = '\r';
				break;

			  case 't':
				c = '\t';
				break;

			  case 'v':
				c = '\v';
				break;

			  case 'x':
				if(!isascii((u_int)**pp) || !isxdigit((u_int)**pp)) {
					if(cstrwarn)
						warn("\\x used with no following hex digits");
					break;
				}
				c = getx(pp);
				break;

			  case '0': case '1': case '2': case '3':
			  case '4': case '5': case '6': case '7':
				(*pp)--;
				c = geto(pp);
				break;
			}
		}
		if(alloc == *plen) {
			alloc += GROW;
			str = xrealloc(str, alloc);
		}
		str[(*plen)++] = c;
	}

	if(alloc == *plen) {
		alloc += 1;
		str = xrealloc(str, alloc);
	}
	str[*plen] = '\0';

	return str;
}

static unsigned char
getx(char **pp)
{
	unsigned char c, ci;
	int len = 2;

	c = 0;
	while(len--) {
		ci = **pp;
		if(!isxdigit(ci))
			break;
		if(isupper(ci))
			c = (c << 4) + ci - 'A' + 10;
		else if(islower(ci))
			c = (c << 4) + ci - 'a' + 10;
		else
			c = (c << 4) + ci - '0';
		(*pp)++;
	}
	return c;
}

static unsigned char
geto(char **pp)
{
	unsigned char ci;
	unsigned c;
	int len = 3;

	c = 0;
	while(len--) {
		ci = **pp;
		if(!isdigit(ci) || ci == '8' || ci == '9')
			break;
		c = (c << 3) + ci - '0';
		(*pp)++;
	}
	if(c > 0377 && cstrwarn)
		warn("escape sequence out of range");
	return c;
}

# ifdef TEST

# include <stdio.h>
int
main(int argc, char *argv[])
{
	char *ret, *str;
	size_t len;

	cstrwarn = 1;

	str = argv[1];
	ret = cstrc(&str, '"', &len);

	fprintf(stderr, "'%s'\n", str);
	fwrite(ret, 1, len, stdout);

	return 0;
}

# endif