1 /* 2 * LZ4 - Fast LZ compression algorithm 3 * Header File 4 * Copyright (C) 2011-2013, Yann Collet. 5 * BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php) 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions are 9 * met: 10 * 11 * * Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * * Redistributions in binary form must reproduce the above 14 * copyright notice, this list of conditions and the following disclaimer 15 * in the documentation and/or other materials provided with the 16 * distribution. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 19 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 20 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 21 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 22 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 23 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 24 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 28 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 29 * 30 * You can contact the author at : 31 * - LZ4 homepage : http://fastcompression.blogspot.com/p/lz4.html 32 * - LZ4 source repository : http://code.google.com/p/lz4/ 33 */ 34 35 #include "fsys_zfs.h" 36 #include <string.h> 37 38 static int LZ4_uncompress_unknownOutputSize(const char *source, char *dest, 39 int isize, int maxOutputSize); 40 41 int 42 lz4_decompress(void *s_start, void *d_start, size_t s_len, size_t d_len) 43 { 44 const uint8_t *src = s_start; 45 uint32_t bufsiz = (src[0] << 24) | (src[1] << 16) | (src[2] << 8) | 46 src[3]; 47 48 /* invalid compressed buffer size encoded at start */ 49 if (bufsiz + 4 > s_len) 50 return (1); 51 52 /* 53 * Returns 0 on success (decompression function returned non-negative) 54 * and non-zero on failure (decompression function returned negative). 55 */ 56 return (LZ4_uncompress_unknownOutputSize(s_start + 4, d_start, bufsiz, 57 d_len) < 0); 58 } 59 60 /* 61 * CPU Feature Detection 62 */ 63 64 /* 32 or 64 bits ? */ 65 #if (defined(__x86_64__) || defined(__x86_64) || defined(__amd64__) || \ 66 defined(__amd64) || defined(__ppc64__) || defined(_WIN64) || \ 67 defined(__LP64__) || defined(_LP64)) 68 #define LZ4_ARCH64 1 69 #else 70 #define LZ4_ARCH64 0 71 #endif 72 73 /* 74 * Little Endian or Big Endian? 75 * Note: overwrite the below #define if you know your architecture endianess. 76 */ 77 #if (defined(__BIG_ENDIAN__) || defined(__BIG_ENDIAN) || \ 78 defined(_BIG_ENDIAN) || defined(_ARCH_PPC) || defined(__PPC__) || \ 79 defined(__PPC) || defined(PPC) || defined(__powerpc__) || \ 80 defined(__powerpc) || defined(powerpc) || \ 81 ((defined(__BYTE_ORDER__)&&(__BYTE_ORDER__ == __ORDER_BIG_ENDIAN__)))) 82 #define LZ4_BIG_ENDIAN 1 83 #else 84 /* 85 * Little Endian assumed. PDP Endian and other very rare endian format 86 * are unsupported. 87 */ 88 #endif 89 90 /* 91 * Compiler Options 92 */ 93 #if __STDC_VERSION__ >= 199901L /* C99 */ 94 /* "restrict" is a known keyword */ 95 #else 96 /* Disable restrict */ 97 #define restrict 98 #endif 99 100 #define GCC_VERSION (__GNUC__ * 100 + __GNUC_MINOR__) 101 102 #define lz4_bswap16(x) ((unsigned short int) ((((x) >> 8) & 0xffu) \ 103 | (((x) & 0xffu) << 8))) 104 105 #if (GCC_VERSION >= 302) || (__INTEL_COMPILER >= 800) || defined(__clang__) 106 #define expect(expr, value) (__builtin_expect((expr), (value))) 107 #else 108 #define expect(expr, value) (expr) 109 #endif 110 111 #define likely(expr) expect((expr) != 0, 1) 112 #define unlikely(expr) expect((expr) != 0, 0) 113 114 /* Basic types */ 115 #define BYTE uint8_t 116 #define U16 uint16_t 117 #define U32 uint32_t 118 #define S32 int32_t 119 #define U64 uint64_t 120 121 typedef struct _U16_S { 122 U16 v; 123 } U16_S; 124 typedef struct _U32_S { 125 U32 v; 126 } U32_S; 127 typedef struct _U64_S { 128 U64 v; 129 } U64_S; 130 131 #define A64(x) (((U64_S *)(x))->v) 132 #define A32(x) (((U32_S *)(x))->v) 133 #define A16(x) (((U16_S *)(x))->v) 134 135 /* 136 * Constants 137 */ 138 #define MINMATCH 4 139 140 #define COPYLENGTH 8 141 #define LASTLITERALS 5 142 143 #define ML_BITS 4 144 #define ML_MASK ((1U<<ML_BITS)-1) 145 #define RUN_BITS (8-ML_BITS) 146 #define RUN_MASK ((1U<<RUN_BITS)-1) 147 148 /* 149 * Architecture-specific macros 150 */ 151 #if LZ4_ARCH64 152 #define STEPSIZE 8 153 #define UARCH U64 154 #define AARCH A64 155 #define LZ4_COPYSTEP(s, d) A64(d) = A64(s); d += 8; s += 8; 156 #define LZ4_COPYPACKET(s, d) LZ4_COPYSTEP(s, d) 157 #define LZ4_SECURECOPY(s, d, e) if (d < e) LZ4_WILDCOPY(s, d, e) 158 #define HTYPE U32 159 #define INITBASE(base) const BYTE* const base = ip 160 #else 161 #define STEPSIZE 4 162 #define UARCH U32 163 #define AARCH A32 164 #define LZ4_COPYSTEP(s, d) A32(d) = A32(s); d += 4; s += 4; 165 #define LZ4_COPYPACKET(s, d) LZ4_COPYSTEP(s, d); LZ4_COPYSTEP(s, d); 166 #define LZ4_SECURECOPY LZ4_WILDCOPY 167 #define HTYPE const BYTE* 168 #define INITBASE(base) const int base = 0 169 #endif 170 171 #if (defined(LZ4_BIG_ENDIAN) && !defined(BIG_ENDIAN_NATIVE_BUT_INCOMPATIBLE)) 172 #define LZ4_READ_LITTLEENDIAN_16(d, s, p) \ 173 { U16 v = A16(p); v = lz4_bswap16(v); d = (s) - v; } 174 #define LZ4_WRITE_LITTLEENDIAN_16(p, i) \ 175 { U16 v = (U16)(i); v = lz4_bswap16(v); A16(p) = v; p += 2; } 176 #else 177 #define LZ4_READ_LITTLEENDIAN_16(d, s, p) { d = (s) - A16(p); } 178 #define LZ4_WRITE_LITTLEENDIAN_16(p, v) { A16(p) = v; p += 2; } 179 #endif 180 181 /* Macros */ 182 #define LZ4_WILDCOPY(s, d, e) do { LZ4_COPYPACKET(s, d) } while (d < e); 183 184 /* Decompression functions */ 185 186 static int 187 LZ4_uncompress_unknownOutputSize(const char *source, 188 char *dest, int isize, int maxOutputSize) 189 { 190 /* Local Variables */ 191 const BYTE *restrict ip = (const BYTE *) source; 192 const BYTE *const iend = ip + isize; 193 const BYTE *restrict ref; 194 195 BYTE *restrict op = (BYTE *) dest; 196 BYTE *const oend = op + maxOutputSize; 197 BYTE *cpy; 198 199 size_t dec[] = { 0, 3, 2, 3, 0, 0, 0, 0 }; 200 201 /* Main Loop */ 202 while (ip < iend) { 203 BYTE token; 204 int length; 205 206 /* get runlength */ 207 token = *ip++; 208 if ((length = (token >> ML_BITS)) == RUN_MASK) { 209 int s = 255; 210 while ((ip < iend) && (s == 255)) { 211 s = *ip++; 212 length += s; 213 } 214 } 215 /* copy literals */ 216 cpy = op + length; 217 /* CORNER-CASE: cpy might overflow. */ 218 if (cpy < op) 219 goto _output_error; /* cpy was overflowed, bail! */ 220 if ((cpy > oend - COPYLENGTH) || 221 (ip + length > iend - COPYLENGTH)) { 222 if (cpy > oend) 223 /* 224 * Error: request to write beyond destination 225 * buffer. 226 */ 227 goto _output_error; 228 if (ip + length > iend) 229 /* 230 * Error : request to read beyond source 231 * buffer. 232 */ 233 goto _output_error; 234 memcpy(op, ip, length); 235 op += length; 236 ip += length; 237 if (ip < iend) 238 /* Error : LZ4 format violation */ 239 goto _output_error; 240 /* Necessarily EOF, due to parsing restrictions. */ 241 break; 242 } 243 LZ4_WILDCOPY(ip, op, cpy); 244 ip -= (op - cpy); 245 op = cpy; 246 247 /* get offset */ 248 LZ4_READ_LITTLEENDIAN_16(ref, cpy, ip); 249 ip += 2; 250 if (ref < (BYTE * const) dest) 251 /* 252 * Error: offset creates reference outside of 253 * destination buffer. 254 */ 255 goto _output_error; 256 257 /* get matchlength */ 258 if ((length = (token & ML_MASK)) == ML_MASK) { 259 while (ip < iend) { 260 int s = *ip++; 261 length += s; 262 if (s == 255) 263 continue; 264 break; 265 } 266 } 267 /* copy repeated sequence */ 268 if unlikely(op - ref < STEPSIZE) { 269 #if LZ4_ARCH64 270 size_t dec2table[] = { 0, 0, 0, -1, 0, 1, 2, 3 }; 271 size_t dec2 = dec2table[op - ref]; 272 #else 273 const int dec2 = 0; 274 #endif 275 *op++ = *ref++; 276 *op++ = *ref++; 277 *op++ = *ref++; 278 *op++ = *ref++; 279 ref -= dec[op - ref]; 280 A32(op) = A32(ref); 281 op += STEPSIZE - 4; 282 ref -= dec2; 283 } else { 284 LZ4_COPYSTEP(ref, op); 285 } 286 cpy = op + length - (STEPSIZE - 4); 287 if (cpy > oend - COPYLENGTH) { 288 if (cpy > oend) 289 /* 290 * Error: request to write outside of 291 * destination buffer. 292 */ 293 goto _output_error; 294 LZ4_SECURECOPY(ref, op, (oend - COPYLENGTH)); 295 while (op < cpy) 296 *op++ = *ref++; 297 op = cpy; 298 if (op == oend) 299 /* 300 * Check EOF (should never happen, since last 301 * 5 bytes are supposed to be literals). 302 */ 303 break; 304 continue; 305 } 306 LZ4_SECURECOPY(ref, op, cpy); 307 op = cpy; /* correction */ 308 } 309 310 /* end of decoding */ 311 return (int)(((char *)op) - dest); 312 313 /* write overflow error detected */ 314 _output_error: 315 return (int)(-(((char *)ip) - source)); 316 } 317