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Diffstat (limited to 'src/journal/compress.c')
| -rw-r--r-- | src/journal/compress.c | 208 |
1 files changed, 208 insertions, 0 deletions
diff --git a/src/journal/compress.c b/src/journal/compress.c new file mode 100644 index 0000000000..ff906581f0 --- /dev/null +++ b/src/journal/compress.c @@ -0,0 +1,208 @@ +/*-*- 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; +} |