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lib/decompress_unlzo.c
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/* * LZO decompressor for the Linux kernel. Code borrowed from the lzo * implementation by Markus Franz Xaver Johannes Oberhumer. * * Linux kernel adaptation: * Copyright (C) 2009 * Albin Tonnerre, Free Electrons <albin.tonnerre@free-electrons.com> * * Original code: * Copyright (C) 1996-2005 Markus Franz Xaver Johannes Oberhumer * All Rights Reserved. * * lzop and the LZO library are free software; you can redistribute them * and/or modify them 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. * * This program 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 this program; see the file COPYING. * If not, write to the Free Software Foundation, Inc., * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. * * Markus F.X.J. Oberhumer * <markus@oberhumer.com> * http://www.oberhumer.com/opensource/lzop/ */ #ifdef STATIC #include "lzo/lzo1x_decompress.c" #else #include <linux/slab.h> #include <linux/decompress/unlzo.h> #endif #include <linux/types.h> #include <linux/lzo.h> #include <linux/decompress/mm.h> #include <linux/compiler.h> #include <asm/unaligned.h> static const unsigned char lzop_magic[] = { 0x89, 0x4c, 0x5a, 0x4f, 0x00, 0x0d, 0x0a, 0x1a, 0x0a }; #define LZO_BLOCK_SIZE (256*1024l) #define HEADER_HAS_FILTER 0x00000800L STATIC inline int INIT parse_header(u8 *input, u8 *skip) { int l; u8 *parse = input; u8 level = 0; u16 version; /* read magic: 9 first bits */ for (l = 0; l < 9; l++) { if (*parse++ != lzop_magic[l]) return 0; } /* get version (2bytes), skip library version (2), * 'need to be extracted' version (2) and * method (1) */ version = get_unaligned_be16(parse); parse += 7; if (version >= 0x0940) level = *parse++; if (get_unaligned_be32(parse) & HEADER_HAS_FILTER) parse += 8; /* flags + filter info */ else parse += 4; /* flags */ /* skip mode and mtime_low */ parse += 8; if (version >= 0x0940) parse += 4; /* skip mtime_high */ l = *parse++; /* don't care about the file name, and skip checksum */ parse += l + 4; *skip = parse - input; return 1; } STATIC inline int INIT unlzo(u8 *input, int in_len, int (*fill) (void *, unsigned int), int (*flush) (void *, unsigned int), u8 *output, int *posp, void (*error_fn) (char *x)) { u8 skip = 0, r = 0; u32 src_len, dst_len; size_t tmp; u8 *in_buf, *in_buf_save, *out_buf; |
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int ret = -1; |
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set_error_fn(error_fn); if (output) { out_buf = output; } else if (!flush) { error("NULL output pointer and no flush function provided"); goto exit; } else { out_buf = malloc(LZO_BLOCK_SIZE); if (!out_buf) { error("Could not allocate output buffer"); goto exit; } } if (input && fill) { error("Both input pointer and fill function provided, don't know what to do"); goto exit_1; } else if (input) { in_buf = input; } else if (!fill || !posp) { error("NULL input pointer and missing position pointer or fill function"); goto exit_1; } else { in_buf = malloc(lzo1x_worst_compress(LZO_BLOCK_SIZE)); if (!in_buf) { error("Could not allocate input buffer"); goto exit_1; } } in_buf_save = in_buf; if (posp) *posp = 0; if (fill) fill(in_buf, lzo1x_worst_compress(LZO_BLOCK_SIZE)); if (!parse_header(input, &skip)) { error("invalid header"); goto exit_2; } in_buf += skip; if (posp) *posp = skip; for (;;) { /* read uncompressed block size */ dst_len = get_unaligned_be32(in_buf); in_buf += 4; /* exit if last block */ if (dst_len == 0) { if (posp) *posp += 4; break; } if (dst_len > LZO_BLOCK_SIZE) { error("dest len longer than block size"); goto exit_2; } /* read compressed block size, and skip block checksum info */ src_len = get_unaligned_be32(in_buf); in_buf += 8; if (src_len <= 0 || src_len > dst_len) { error("file corrupted"); goto exit_2; } /* decompress */ tmp = dst_len; |
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/* When the input data is not compressed at all, * lzo1x_decompress_safe will fail, so call memcpy() * instead */ if (unlikely(dst_len == src_len)) memcpy(out_buf, in_buf, src_len); else { r = lzo1x_decompress_safe((u8 *) in_buf, src_len, |
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out_buf, &tmp); |
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if (r != LZO_E_OK || dst_len != tmp) { error("Compressed data violation"); goto exit_2; } |
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} |
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if (flush) flush(out_buf, dst_len); if (output) out_buf += dst_len; if (posp) *posp += src_len + 12; if (fill) { in_buf = in_buf_save; fill(in_buf, lzo1x_worst_compress(LZO_BLOCK_SIZE)); } else in_buf += src_len; } |
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ret = 0; |
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exit_2: if (!input) free(in_buf); exit_1: if (!output) free(out_buf); exit: |
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return ret; |
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} #define decompress unlzo |