compress.c revision e4e61fdbed832a2bd3f5dcd47623872d9081599c
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
/***
This file is part of systemd.
Copyright 2011 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <assert.h>
#include <stdlib.h>
#include <string.h>
#include <lzma.h>
#include "compress.h"
bool compress_blob(const void *src, uint64_t src_size, void *dst, uint64_t *dst_size) {
lzma_stream s = LZMA_STREAM_INIT;
lzma_ret ret;
bool b = false;
assert(src);
assert(src_size > 0);
assert(dst);
assert(dst_size);
/* Returns false if we couldn't compress the data or the
* compressed result is longer than the original */
ret = lzma_easy_encoder(&s, LZMA_PRESET_DEFAULT, LZMA_CHECK_NONE);
if (ret != LZMA_OK)
return false;
s.next_in = src;
s.avail_in = src_size;
s.next_out = dst;
s.avail_out = src_size;
/* Does it fit? */
if (lzma_code(&s, LZMA_FINISH) != LZMA_STREAM_END)
goto fail;
/* Is it actually shorter? */
if (s.avail_out == 0)
goto fail;
*dst_size = src_size - s.avail_out;
b = true;
fail:
lzma_end(&s);
return b;
}
bool uncompress_blob(const void *src, uint64_t src_size,
void **dst, uint64_t *dst_alloc_size, uint64_t* dst_size) {
lzma_stream s = LZMA_STREAM_INIT;
lzma_ret ret;
bool b = false;
assert(src);
assert(src_size > 0);
assert(dst);
assert(dst_alloc_size);
assert(dst_size);
assert(*dst_alloc_size == 0 || *dst);
ret = lzma_stream_decoder(&s, UINT64_MAX, 0);
if (ret != LZMA_OK)
return false;
if (*dst_alloc_size <= src_size) {
void *p;
p = realloc(*dst, src_size*2);
if (!p)
return false;
*dst = p;
*dst_alloc_size = src_size*2;
}
s.next_in = src;
s.avail_in = src_size;
s.next_out = *dst;
s.avail_out = *dst_alloc_size;
for (;;) {
void *p;
ret = lzma_code(&s, LZMA_FINISH);
if (ret == LZMA_STREAM_END)
break;
if (ret != LZMA_OK)
goto fail;
p = realloc(*dst, *dst_alloc_size*2);
if (!p)
goto fail;
s.next_out = (uint8_t*) p + ((uint8_t*) s.next_out - (uint8_t*) *dst);
s.avail_out += *dst_alloc_size;
*dst = p;
*dst_alloc_size *= 2;
}
*dst_size = *dst_alloc_size - s.avail_out;
b = true;
fail:
lzma_end(&s);
return b;
}
bool uncompress_startswith(const void *src, uint64_t src_size,
void **buffer, uint64_t *buffer_size,
const void *prefix, uint64_t prefix_len,
uint8_t extra) {
lzma_stream s = LZMA_STREAM_INIT;
lzma_ret ret;
bool b = false;
/* Checks whether the uncompressed blob starts with the
* mentioned prefix. The byte extra needs to follow the
* prefix */
assert(src);
assert(src_size > 0);
assert(buffer);
assert(buffer_size);
assert(prefix);
assert(*buffer_size == 0 || *buffer);
ret = lzma_stream_decoder(&s, UINT64_MAX, 0);
if (ret != LZMA_OK)
return false;
if (*buffer_size <= prefix_len) {
void *p;
p = realloc(*buffer, prefix_len*2);
if (!p)
return false;
*buffer = p;
*buffer_size = prefix_len*2;
}
s.next_in = src;
s.avail_in = src_size;
s.next_out = *buffer;
s.avail_out = *buffer_size;
for (;;) {
void *p;
ret = lzma_code(&s, LZMA_FINISH);
if (ret != LZMA_STREAM_END && ret != LZMA_OK)
goto fail;
if ((*buffer_size - s.avail_out > prefix_len) &&
memcmp(*buffer, prefix, prefix_len) == 0 &&
((const uint8_t*) *buffer)[prefix_len] == extra)
break;
if (ret == LZMA_STREAM_END)
goto fail;
p = realloc(*buffer, *buffer_size*2);
if (!p)
goto fail;
s.next_out = (uint8_t*) p + ((uint8_t*) s.next_out - (uint8_t*) *buffer);
s.avail_out += *buffer_size;
*buffer = p;
*buffer_size *= 2;
}
b = true;
fail:
lzma_end(&s);
return b;
}