/*
* Copyright (c) 2014 Martin Decky
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* - 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.
* - The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 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.
*/
#include <stdint.h>
#include <stddef.h>
#include <errno.h>
#include <mem.h>
#include <byteorder.h>
#include <stdlib.h>
#include "gzip.h"
#include "inflate.h"
#define GZIP_ID1 UINT8_C(0x1f)
#define GZIP_ID2 UINT8_C(0x8b)
#define GZIP_METHOD_DEFLATE UINT8_C(0x08)
#define GZIP_FLAGS_MASK UINT8_C(0x1f)
#define GZIP_FLAG_FHCRC UINT8_C(1 << 1)
#define GZIP_FLAG_FEXTRA UINT8_C(1 << 2)
#define GZIP_FLAG_FNAME UINT8_C(1 << 3)
#define GZIP_FLAG_FCOMMENT UINT8_C(1 << 4)
typedef struct {
uint8_t id1;
uint8_t id2;
uint8_t method;
uint8_t flags;
uint32_t mtime;
uint8_t extra_flags;
uint8_t os;
} __attribute__((packed)) gzip_header_t;
typedef struct {
uint32_t crc32;
uint32_t size;
} __attribute__((packed)) gzip_footer_t;
/** Expand GZIP compressed data
*
* The routine allocates the output buffer based
* on the size encoded in the input stream. This
* effectively limits the size of the uncompressed
* data to 4 GiB (expanding input streams that actually
* encode more data will always fail).
*
* So far, no CRC is perfomed.
*
* @param[in] src Source data buffer.
* @param[in] srclen Source buffer size (bytes).
* @param[out] dest Destination data buffer.
* @param[out] destlen Destination buffer size (bytes).
*
* @return EOK on success.
* @return ENOENT on distance too large.
* @return EINVAL on invalid Huffman code, invalid deflate data,
* invalid compression method or invalid stream.
* @return ELIMIT on input buffer overrun.
* @return ENOMEM on output buffer overrun.
*
*/
errno_t gzip_expand(void *src, size_t srclen, void **dest, size_t *destlen)
{
gzip_header_t header;
gzip_footer_t footer;
if ((srclen < sizeof(header)) || (srclen < sizeof(footer)))
return EINVAL;
/* Decode header and footer */
memcpy(&header, src, sizeof(header));
memcpy(&footer, src + srclen - sizeof(footer), sizeof(footer));
if ((header.id1 != GZIP_ID1) ||
(header.id2 != GZIP_ID2) ||
(header.method != GZIP_METHOD_DEFLATE) ||
((header.flags & (~GZIP_FLAGS_MASK)) != 0))
return EINVAL;
*destlen = uint32_t_le2host(footer.size);
/* Ignore extra metadata */
void *stream = src + sizeof(header);
size_t stream_length = srclen - sizeof(header) - sizeof(footer);
if ((header.flags & GZIP_FLAG_FEXTRA) != 0) {
uint16_t extra_length;
if (stream_length < sizeof(extra_length))
return EINVAL;
memcpy(&extra_length, stream, sizeof(extra_length));
stream += sizeof(extra_length);
stream_length -= sizeof(extra_length);
if (stream_length < extra_length)
return EINVAL;
stream += extra_length;
stream_length -= extra_length;
}
if ((header.flags & GZIP_FLAG_FNAME) != 0) {
while (*((uint8_t *) stream) != 0) {
if (stream_length == 0)
return EINVAL;
stream++;
stream_length--;
}
if (stream_length == 0)
return EINVAL;
stream++;
stream_length--;
}
if ((header.flags & GZIP_FLAG_FCOMMENT) != 0) {
while (*((uint8_t *) stream) != 0) {
if (stream_length == 0)
return EINVAL;
stream++;
stream_length--;
}
if (stream_length == 0)
return EINVAL;
stream++;
stream_length--;
}
if ((header.flags & GZIP_FLAG_FHCRC) != 0) {
if (stream_length < 2)
return EINVAL;
stream += 2;
stream_length -= 2;
}
/* Allocate output buffer and inflate the data */
*dest = malloc(*destlen);
if (*dest == NULL)
return ENOMEM;
errno_t ret = inflate(stream, stream_length, *dest, *destlen);
if (ret != EOK) {
free(dest);
return ret;
}
return EOK;
}