|
| 1 | +/* |
| 2 | + * LZ4 Decompressor for Linux kernel |
| 3 | + * |
| 4 | + * Copyright (C) 2013 LG Electronics Co., Ltd. (http://www.lge.com/) |
| 5 | + * |
| 6 | + * Based on LZ4 implementation by Yann Collet. |
| 7 | + * |
| 8 | + * LZ4 - Fast LZ compression algorithm |
| 9 | + * Copyright (C) 2011-2012, Yann Collet. |
| 10 | + * BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php) |
| 11 | + * |
| 12 | + * Redistribution and use in source and binary forms, with or without |
| 13 | + * modification, are permitted provided that the following conditions are |
| 14 | + * met: |
| 15 | + * |
| 16 | + * * Redistributions of source code must retain the above copyright |
| 17 | + * notice, this list of conditions and the following disclaimer. |
| 18 | + * * Redistributions in binary form must reproduce the above |
| 19 | + * copyright notice, this list of conditions and the following disclaimer |
| 20 | + * in the documentation and/or other materials provided with the |
| 21 | + * distribution. |
| 22 | + * |
| 23 | + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| 24 | + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| 25 | + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| 26 | + * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
| 27 | + * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| 28 | + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| 29 | + * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| 30 | + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| 31 | + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| 32 | + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| 33 | + * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| 34 | + * |
| 35 | + * You can contact the author at : |
| 36 | + * - LZ4 homepage : http://fastcompression.blogspot.com/p/lz4.html |
| 37 | + * - LZ4 source repository : http://code.google.com/p/lz4/ |
| 38 | + */ |
| 39 | + |
| 40 | +#ifndef STATIC |
| 41 | +#include <linux/module.h> |
| 42 | +#include <linux/kernel.h> |
| 43 | +#endif |
| 44 | +#include <linux/lz4.h> |
| 45 | + |
| 46 | +#include <asm/unaligned.h> |
| 47 | + |
| 48 | +#include "lz4defs.h" |
| 49 | + |
| 50 | +static int lz4_uncompress(const char *source, char *dest, int osize) |
| 51 | +{ |
| 52 | + const BYTE *ip = (const BYTE *) source; |
| 53 | + const BYTE *ref; |
| 54 | + BYTE *op = (BYTE *) dest; |
| 55 | + BYTE * const oend = op + osize; |
| 56 | + BYTE *cpy; |
| 57 | + unsigned token; |
| 58 | + size_t length; |
| 59 | + size_t dec32table[] = {0, 3, 2, 3, 0, 0, 0, 0}; |
| 60 | +#if LZ4_ARCH64 |
| 61 | + size_t dec64table[] = {0, 0, 0, -1, 0, 1, 2, 3}; |
| 62 | +#endif |
| 63 | + |
| 64 | + while (1) { |
| 65 | + |
| 66 | + /* get runlength */ |
| 67 | + token = *ip++; |
| 68 | + length = (token >> ML_BITS); |
| 69 | + if (length == RUN_MASK) { |
| 70 | + size_t len; |
| 71 | + |
| 72 | + len = *ip++; |
| 73 | + for (; len == 255; length += 255) |
| 74 | + len = *ip++; |
| 75 | + length += len; |
| 76 | + } |
| 77 | + |
| 78 | + /* copy literals */ |
| 79 | + cpy = op + length; |
| 80 | + if (unlikely(cpy > oend - COPYLENGTH)) { |
| 81 | + /* |
| 82 | + * Error: not enough place for another match |
| 83 | + * (min 4) + 5 literals |
| 84 | + */ |
| 85 | + if (cpy != oend) |
| 86 | + goto _output_error; |
| 87 | + |
| 88 | + memcpy(op, ip, length); |
| 89 | + ip += length; |
| 90 | + break; /* EOF */ |
| 91 | + } |
| 92 | + LZ4_WILDCOPY(ip, op, cpy); |
| 93 | + ip -= (op - cpy); |
| 94 | + op = cpy; |
| 95 | + |
| 96 | + /* get offset */ |
| 97 | + LZ4_READ_LITTLEENDIAN_16(ref, cpy, ip); |
| 98 | + ip += 2; |
| 99 | + |
| 100 | + /* Error: offset create reference outside destination buffer */ |
| 101 | + if (unlikely(ref < (BYTE *const) dest)) |
| 102 | + goto _output_error; |
| 103 | + |
| 104 | + /* get matchlength */ |
| 105 | + length = token & ML_MASK; |
| 106 | + if (length == ML_MASK) { |
| 107 | + for (; *ip == 255; length += 255) |
| 108 | + ip++; |
| 109 | + length += *ip++; |
| 110 | + } |
| 111 | + |
| 112 | + /* copy repeated sequence */ |
| 113 | + if (unlikely((op - ref) < STEPSIZE)) { |
| 114 | +#if LZ4_ARCH64 |
| 115 | + size_t dec64 = dec64table[op - ref]; |
| 116 | +#else |
| 117 | + const int dec64 = 0; |
| 118 | +#endif |
| 119 | + op[0] = ref[0]; |
| 120 | + op[1] = ref[1]; |
| 121 | + op[2] = ref[2]; |
| 122 | + op[3] = ref[3]; |
| 123 | + op += 4; |
| 124 | + ref += 4; |
| 125 | + ref -= dec32table[op-ref]; |
| 126 | + PUT4(ref, op); |
| 127 | + op += STEPSIZE - 4; |
| 128 | + ref -= dec64; |
| 129 | + } else { |
| 130 | + LZ4_COPYSTEP(ref, op); |
| 131 | + } |
| 132 | + cpy = op + length - (STEPSIZE - 4); |
| 133 | + if (cpy > (oend - COPYLENGTH)) { |
| 134 | + |
| 135 | + /* Error: request to write beyond destination buffer */ |
| 136 | + if (cpy > oend) |
| 137 | + goto _output_error; |
| 138 | + LZ4_SECURECOPY(ref, op, (oend - COPYLENGTH)); |
| 139 | + while (op < cpy) |
| 140 | + *op++ = *ref++; |
| 141 | + op = cpy; |
| 142 | + /* |
| 143 | + * Check EOF (should never happen, since last 5 bytes |
| 144 | + * are supposed to be literals) |
| 145 | + */ |
| 146 | + if (op == oend) |
| 147 | + goto _output_error; |
| 148 | + continue; |
| 149 | + } |
| 150 | + LZ4_SECURECOPY(ref, op, cpy); |
| 151 | + op = cpy; /* correction */ |
| 152 | + } |
| 153 | + /* end of decoding */ |
| 154 | + return (int) (((char *)ip) - source); |
| 155 | + |
| 156 | + /* write overflow error detected */ |
| 157 | +_output_error: |
| 158 | + return (int) (-(((char *)ip) - source)); |
| 159 | +} |
| 160 | + |
| 161 | +static int lz4_uncompress_unknownoutputsize(const char *source, char *dest, |
| 162 | + int isize, size_t maxoutputsize) |
| 163 | +{ |
| 164 | + const BYTE *ip = (const BYTE *) source; |
| 165 | + const BYTE *const iend = ip + isize; |
| 166 | + const BYTE *ref; |
| 167 | + |
| 168 | + |
| 169 | + BYTE *op = (BYTE *) dest; |
| 170 | + BYTE * const oend = op + maxoutputsize; |
| 171 | + BYTE *cpy; |
| 172 | + |
| 173 | + size_t dec32table[] = {0, 3, 2, 3, 0, 0, 0, 0}; |
| 174 | +#if LZ4_ARCH64 |
| 175 | + size_t dec64table[] = {0, 0, 0, -1, 0, 1, 2, 3}; |
| 176 | +#endif |
| 177 | + |
| 178 | + /* Main Loop */ |
| 179 | + while (ip < iend) { |
| 180 | + |
| 181 | + unsigned token; |
| 182 | + size_t length; |
| 183 | + |
| 184 | + /* get runlength */ |
| 185 | + token = *ip++; |
| 186 | + length = (token >> ML_BITS); |
| 187 | + if (length == RUN_MASK) { |
| 188 | + int s = 255; |
| 189 | + while ((ip < iend) && (s == 255)) { |
| 190 | + s = *ip++; |
| 191 | + length += s; |
| 192 | + } |
| 193 | + } |
| 194 | + /* copy literals */ |
| 195 | + cpy = op + length; |
| 196 | + if ((cpy > oend - COPYLENGTH) || |
| 197 | + (ip + length > iend - COPYLENGTH)) { |
| 198 | + |
| 199 | + if (cpy > oend) |
| 200 | + goto _output_error;/* writes beyond buffer */ |
| 201 | + |
| 202 | + if (ip + length != iend) |
| 203 | + goto _output_error;/* |
| 204 | + * Error: LZ4 format requires |
| 205 | + * to consume all input |
| 206 | + * at this stage |
| 207 | + */ |
| 208 | + memcpy(op, ip, length); |
| 209 | + op += length; |
| 210 | + break;/* Necessarily EOF, due to parsing restrictions */ |
| 211 | + } |
| 212 | + LZ4_WILDCOPY(ip, op, cpy); |
| 213 | + ip -= (op - cpy); |
| 214 | + op = cpy; |
| 215 | + |
| 216 | + /* get offset */ |
| 217 | + LZ4_READ_LITTLEENDIAN_16(ref, cpy, ip); |
| 218 | + ip += 2; |
| 219 | + if (ref < (BYTE * const) dest) |
| 220 | + goto _output_error; |
| 221 | + /* |
| 222 | + * Error : offset creates reference |
| 223 | + * outside of destination buffer |
| 224 | + */ |
| 225 | + |
| 226 | + /* get matchlength */ |
| 227 | + length = (token & ML_MASK); |
| 228 | + if (length == ML_MASK) { |
| 229 | + while (ip < iend) { |
| 230 | + int s = *ip++; |
| 231 | + length += s; |
| 232 | + if (s == 255) |
| 233 | + continue; |
| 234 | + break; |
| 235 | + } |
| 236 | + } |
| 237 | + |
| 238 | + /* copy repeated sequence */ |
| 239 | + if (unlikely((op - ref) < STEPSIZE)) { |
| 240 | +#if LZ4_ARCH64 |
| 241 | + size_t dec64 = dec64table[op - ref]; |
| 242 | +#else |
| 243 | + const int dec64 = 0; |
| 244 | +#endif |
| 245 | + op[0] = ref[0]; |
| 246 | + op[1] = ref[1]; |
| 247 | + op[2] = ref[2]; |
| 248 | + op[3] = ref[3]; |
| 249 | + op += 4; |
| 250 | + ref += 4; |
| 251 | + ref -= dec32table[op - ref]; |
| 252 | + PUT4(ref, op); |
| 253 | + op += STEPSIZE - 4; |
| 254 | + ref -= dec64; |
| 255 | + } else { |
| 256 | + LZ4_COPYSTEP(ref, op); |
| 257 | + } |
| 258 | + cpy = op + length - (STEPSIZE-4); |
| 259 | + if (cpy > oend - COPYLENGTH) { |
| 260 | + if (cpy > oend) |
| 261 | + goto _output_error; /* write outside of buf */ |
| 262 | + |
| 263 | + LZ4_SECURECOPY(ref, op, (oend - COPYLENGTH)); |
| 264 | + while (op < cpy) |
| 265 | + *op++ = *ref++; |
| 266 | + op = cpy; |
| 267 | + /* |
| 268 | + * Check EOF (should never happen, since last 5 bytes |
| 269 | + * are supposed to be literals) |
| 270 | + */ |
| 271 | + if (op == oend) |
| 272 | + goto _output_error; |
| 273 | + continue; |
| 274 | + } |
| 275 | + LZ4_SECURECOPY(ref, op, cpy); |
| 276 | + op = cpy; /* correction */ |
| 277 | + } |
| 278 | + /* end of decoding */ |
| 279 | + return (int) (((char *) op) - dest); |
| 280 | + |
| 281 | + /* write overflow error detected */ |
| 282 | +_output_error: |
| 283 | + return (int) (-(((char *) ip) - source)); |
| 284 | +} |
| 285 | + |
| 286 | +int lz4_decompress(const char *src, size_t *src_len, char *dest, |
| 287 | + size_t actual_dest_len) |
| 288 | +{ |
| 289 | + int ret = -1; |
| 290 | + int input_len = 0; |
| 291 | + |
| 292 | + input_len = lz4_uncompress(src, dest, actual_dest_len); |
| 293 | + if (input_len < 0) |
| 294 | + goto exit_0; |
| 295 | + *src_len = input_len; |
| 296 | + |
| 297 | + return 0; |
| 298 | +exit_0: |
| 299 | + return ret; |
| 300 | +} |
| 301 | +#ifndef STATIC |
| 302 | +EXPORT_SYMBOL_GPL(lz4_decompress); |
| 303 | +#endif |
| 304 | + |
| 305 | +int lz4_decompress_unknownoutputsize(const char *src, size_t src_len, |
| 306 | + char *dest, size_t *dest_len) |
| 307 | +{ |
| 308 | + int ret = -1; |
| 309 | + int out_len = 0; |
| 310 | + |
| 311 | + out_len = lz4_uncompress_unknownoutputsize(src, dest, src_len, |
| 312 | + *dest_len); |
| 313 | + if (out_len < 0) |
| 314 | + goto exit_0; |
| 315 | + *dest_len = out_len; |
| 316 | + |
| 317 | + return 0; |
| 318 | +exit_0: |
| 319 | + return ret; |
| 320 | +} |
| 321 | +#ifndef STATIC |
| 322 | +EXPORT_SYMBOL_GPL(lz4_decompress_unknownoutputsize); |
| 323 | + |
| 324 | +MODULE_LICENSE("GPL"); |
| 325 | +MODULE_DESCRIPTION("LZ4 Decompressor"); |
| 326 | +#endif |
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