/*-
 * Copyright (c) 1999, 2000, 2001, 2002, 2003 Lev Walkin <vlm@lionet.info>.
 * All rights reserved.
 *
 * 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 THE 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 THE 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.
 *
 * $Id: qprint.c,v 1.5 2005/12/11 01:53:35 vlm Exp $
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>

#ifdef	HAVE_CONFIG_H
#include "config.h"
#endif

#include <sf_mem.h>
#include <sf_mime.h>

int _sf_in_mime_words;	/* Externally visible */
static char *_sf_qp_buf = NULL;

char *
quoted_printable_decode(const char *str, size_t *size) {
	char *buf;
	char *s;
	register int n;

	if(str == NULL) {
		/*
		 * Return an empty string.
		 */
		if(_sf_qp_buf)
			free(_sf_qp_buf);
		_sf_qp_buf=sf_strdup("");
		if(size) *size = 0;
		return _sf_qp_buf;
	}

	/*
	 * Allocate sufficient space to hold decoded string.
	 */
	s=buf=(char *)sf_malloc((size?*size:strlen(str)) + 1);
	if(buf == NULL)
		/* ENOMEM? */
		return NULL;

	for(; *str; str++) {

		if(_sf_in_mime_words && (*str == '_')) {
			*s++ = ' ';
			continue;
		}

		if(*str == '=') {
			*s = '\0';
			n = *++str; 
			if(n == '\0') {
				str--;
				break;
			}

			if(str[1] == '\0')
				break;

			switch(n) {
			case '0': case '1': case '2': case '3': case '4':
			case '5': case '6': case '7': case '8': case '9':
				*s = n - '0';
				break;
			case 'A': case 'B': case 'C':
			case 'D': case 'E': case 'F':
				*s=n - 'A' + 10;
				break;
			case 'a': case 'b': case 'c':
			case 'd': case 'e': case 'f':
				*s=n - 'a' + 10;
				break;
			case '\r':
			case '\n':
				continue;
			default:
				*s++ = '=';
				*s++ = n;
				continue;
			}

			*s *= 16;
			n = *++str;

			switch(n) {
			case '0': case '1': case '2': case '3': case '4':
			case '5': case '6': case '7': case '8': case '9':
				*s += n - '0';
				break;
			case 'A': case 'B': case 'C':
			case 'D': case 'E': case 'F':
				*s += n - 'A' + 10;
				break;
			case 'a': case 'b': case 'c':
			case 'd': case 'e': case 'f':
				*s += n - 'a' + 10;
				break;
			case '\r':
			case '\n':
				*s++ = n;
				continue;
			default:
				*s = ' ';
				continue;
			}

			s++;
			continue;
		}
		*s++ = *str;
	}
	*s = '\0';

	if(_sf_qp_buf)
		free(_sf_qp_buf);
	if(size) *size = (s - buf);
	return (_sf_qp_buf=buf);
}