| 1 | /* |
| 2 | * LZO 1x decompression |
| 3 | * Copyright (c) 2006 Reimar Doeffinger |
| 4 | * |
| 5 | * This file is part of FFmpeg. |
| 6 | * |
| 7 | * FFmpeg is free software; you can redistribute it and/or |
| 8 | * modify it under the terms of the GNU Lesser General Public |
| 9 | * License as published by the Free Software Foundation; either |
| 10 | * version 2.1 of the License, or (at your option) any later version. |
| 11 | * |
| 12 | * FFmpeg is distributed in the hope that it will be useful, |
| 13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 15 | * Lesser General Public License for more details. |
| 16 | * |
| 17 | * You should have received a copy of the GNU Lesser General Public |
| 18 | * License along with FFmpeg; if not, write to the Free Software |
| 19 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| 20 | */ |
| 21 | |
| 22 | #include <string.h> |
| 23 | |
| 24 | #include "avutil.h" |
| 25 | #include "avassert.h" |
| 26 | #include "common.h" |
| 27 | #include "intreadwrite.h" |
| 28 | #include "lzo.h" |
| 29 | |
| 30 | /// Define if we may write up to 12 bytes beyond the output buffer. |
| 31 | #define OUTBUF_PADDED 1 |
| 32 | /// Define if we may read up to 8 bytes beyond the input buffer. |
| 33 | #define INBUF_PADDED 1 |
| 34 | |
| 35 | typedef struct LZOContext { |
| 36 | const uint8_t *in, *in_end; |
| 37 | uint8_t *out_start, *out, *out_end; |
| 38 | int error; |
| 39 | } LZOContext; |
| 40 | |
| 41 | /** |
| 42 | * @brief Reads one byte from the input buffer, avoiding an overrun. |
| 43 | * @return byte read |
| 44 | */ |
| 45 | static inline int get_byte(LZOContext *c) |
| 46 | { |
| 47 | if (c->in < c->in_end) |
| 48 | return *c->in++; |
| 49 | c->error |= AV_LZO_INPUT_DEPLETED; |
| 50 | return 1; |
| 51 | } |
| 52 | |
| 53 | #ifdef INBUF_PADDED |
| 54 | #define GETB(c) (*(c).in++) |
| 55 | #else |
| 56 | #define GETB(c) get_byte(&(c)) |
| 57 | #endif |
| 58 | |
| 59 | /** |
| 60 | * @brief Decodes a length value in the coding used by lzo. |
| 61 | * @param x previous byte value |
| 62 | * @param mask bits used from x |
| 63 | * @return decoded length value |
| 64 | */ |
| 65 | static inline int get_len(LZOContext *c, int x, int mask) |
| 66 | { |
| 67 | int cnt = x & mask; |
| 68 | if (!cnt) { |
| 69 | while (!(x = get_byte(c))) { |
| 70 | if (cnt >= INT_MAX - 1000) { |
| 71 | c->error |= AV_LZO_ERROR; |
| 72 | break; |
| 73 | } |
| 74 | cnt += 255; |
| 75 | } |
| 76 | cnt += mask + x; |
| 77 | } |
| 78 | return cnt; |
| 79 | } |
| 80 | |
| 81 | /** |
| 82 | * @brief Copies bytes from input to output buffer with checking. |
| 83 | * @param cnt number of bytes to copy, must be >= 0 |
| 84 | */ |
| 85 | static inline void copy(LZOContext *c, int cnt) |
| 86 | { |
| 87 | register const uint8_t *src = c->in; |
| 88 | register uint8_t *dst = c->out; |
| 89 | av_assert0(cnt >= 0); |
| 90 | if (cnt > c->in_end - src) { |
| 91 | cnt = FFMAX(c->in_end - src, 0); |
| 92 | c->error |= AV_LZO_INPUT_DEPLETED; |
| 93 | } |
| 94 | if (cnt > c->out_end - dst) { |
| 95 | cnt = FFMAX(c->out_end - dst, 0); |
| 96 | c->error |= AV_LZO_OUTPUT_FULL; |
| 97 | } |
| 98 | #if defined(INBUF_PADDED) && defined(OUTBUF_PADDED) |
| 99 | AV_COPY32U(dst, src); |
| 100 | src += 4; |
| 101 | dst += 4; |
| 102 | cnt -= 4; |
| 103 | if (cnt > 0) |
| 104 | #endif |
| 105 | memcpy(dst, src, cnt); |
| 106 | c->in = src + cnt; |
| 107 | c->out = dst + cnt; |
| 108 | } |
| 109 | |
| 110 | /** |
| 111 | * @brief Copies previously decoded bytes to current position. |
| 112 | * @param back how many bytes back we start, must be > 0 |
| 113 | * @param cnt number of bytes to copy, must be > 0 |
| 114 | * |
| 115 | * cnt > back is valid, this will copy the bytes we just copied, |
| 116 | * thus creating a repeating pattern with a period length of back. |
| 117 | */ |
| 118 | static inline void copy_backptr(LZOContext *c, int back, int cnt) |
| 119 | { |
| 120 | register uint8_t *dst = c->out; |
| 121 | av_assert0(cnt > 0); |
| 122 | if (dst - c->out_start < back) { |
| 123 | c->error |= AV_LZO_INVALID_BACKPTR; |
| 124 | return; |
| 125 | } |
| 126 | if (cnt > c->out_end - dst) { |
| 127 | cnt = FFMAX(c->out_end - dst, 0); |
| 128 | c->error |= AV_LZO_OUTPUT_FULL; |
| 129 | } |
| 130 | av_memcpy_backptr(dst, back, cnt); |
| 131 | c->out = dst + cnt; |
| 132 | } |
| 133 | |
| 134 | int av_lzo1x_decode(void *out, int *outlen, const void *in, int *inlen) |
| 135 | { |
| 136 | int state = 0; |
| 137 | int x; |
| 138 | LZOContext c; |
| 139 | if (*outlen <= 0 || *inlen <= 0) { |
| 140 | int res = 0; |
| 141 | if (*outlen <= 0) |
| 142 | res |= AV_LZO_OUTPUT_FULL; |
| 143 | if (*inlen <= 0) |
| 144 | res |= AV_LZO_INPUT_DEPLETED; |
| 145 | return res; |
| 146 | } |
| 147 | c.in = in; |
| 148 | c.in_end = (const uint8_t *)in + *inlen; |
| 149 | c.out = c.out_start = out; |
| 150 | c.out_end = (uint8_t *)out + *outlen; |
| 151 | c.error = 0; |
| 152 | x = GETB(c); |
| 153 | if (x > 17) { |
| 154 | copy(&c, x - 17); |
| 155 | x = GETB(c); |
| 156 | if (x < 16) |
| 157 | c.error |= AV_LZO_ERROR; |
| 158 | } |
| 159 | if (c.in > c.in_end) |
| 160 | c.error |= AV_LZO_INPUT_DEPLETED; |
| 161 | while (!c.error) { |
| 162 | int cnt, back; |
| 163 | if (x > 15) { |
| 164 | if (x > 63) { |
| 165 | cnt = (x >> 5) - 1; |
| 166 | back = (GETB(c) << 3) + ((x >> 2) & 7) + 1; |
| 167 | } else if (x > 31) { |
| 168 | cnt = get_len(&c, x, 31); |
| 169 | x = GETB(c); |
| 170 | back = (GETB(c) << 6) + (x >> 2) + 1; |
| 171 | } else { |
| 172 | cnt = get_len(&c, x, 7); |
| 173 | back = (1 << 14) + ((x & 8) << 11); |
| 174 | x = GETB(c); |
| 175 | back += (GETB(c) << 6) + (x >> 2); |
| 176 | if (back == (1 << 14)) { |
| 177 | if (cnt != 1) |
| 178 | c.error |= AV_LZO_ERROR; |
| 179 | break; |
| 180 | } |
| 181 | } |
| 182 | } else if (!state) { |
| 183 | cnt = get_len(&c, x, 15); |
| 184 | copy(&c, cnt + 3); |
| 185 | x = GETB(c); |
| 186 | if (x > 15) |
| 187 | continue; |
| 188 | cnt = 1; |
| 189 | back = (1 << 11) + (GETB(c) << 2) + (x >> 2) + 1; |
| 190 | } else { |
| 191 | cnt = 0; |
| 192 | back = (GETB(c) << 2) + (x >> 2) + 1; |
| 193 | } |
| 194 | copy_backptr(&c, back, cnt + 2); |
| 195 | state = |
| 196 | cnt = x & 3; |
| 197 | copy(&c, cnt); |
| 198 | x = GETB(c); |
| 199 | } |
| 200 | *inlen = c.in_end - c.in; |
| 201 | if (c.in > c.in_end) |
| 202 | *inlen = 0; |
| 203 | *outlen = c.out_end - c.out; |
| 204 | return c.error; |
| 205 | } |
| 206 | |
| 207 | #ifdef TEST |
| 208 | #include <stdio.h> |
| 209 | #include <lzo/lzo1x.h> |
| 210 | #include "log.h" |
| 211 | #define MAXSZ (10*1024*1024) |
| 212 | |
| 213 | /* Define one of these to 1 if you wish to benchmark liblzo |
| 214 | * instead of our native implementation. */ |
| 215 | #define BENCHMARK_LIBLZO_SAFE 0 |
| 216 | #define BENCHMARK_LIBLZO_UNSAFE 0 |
| 217 | |
| 218 | int main(int argc, char *argv[]) { |
| 219 | FILE *in = fopen(argv[1], "rb"); |
| 220 | int comp_level = argc > 2 ? atoi(argv[2]) : 0; |
| 221 | uint8_t *orig = av_malloc(MAXSZ + 16); |
| 222 | uint8_t *comp = av_malloc(2*MAXSZ + 16); |
| 223 | uint8_t *decomp = av_malloc(MAXSZ + 16); |
| 224 | size_t s = fread(orig, 1, MAXSZ, in); |
| 225 | lzo_uint clen = 0; |
| 226 | long tmp[LZO1X_MEM_COMPRESS]; |
| 227 | int inlen, outlen; |
| 228 | int i; |
| 229 | av_log_set_level(AV_LOG_DEBUG); |
| 230 | if (comp_level == 0) { |
| 231 | lzo1x_1_compress(orig, s, comp, &clen, tmp); |
| 232 | } else if (comp_level == 11) { |
| 233 | lzo1x_1_11_compress(orig, s, comp, &clen, tmp); |
| 234 | } else if (comp_level == 12) { |
| 235 | lzo1x_1_12_compress(orig, s, comp, &clen, tmp); |
| 236 | } else if (comp_level == 15) { |
| 237 | lzo1x_1_15_compress(orig, s, comp, &clen, tmp); |
| 238 | } else |
| 239 | lzo1x_999_compress(orig, s, comp, &clen, tmp); |
| 240 | for (i = 0; i < 300; i++) { |
| 241 | START_TIMER |
| 242 | inlen = clen; outlen = MAXSZ; |
| 243 | #if BENCHMARK_LIBLZO_SAFE |
| 244 | if (lzo1x_decompress_safe(comp, inlen, decomp, &outlen, NULL)) |
| 245 | #elif BENCHMARK_LIBLZO_UNSAFE |
| 246 | if (lzo1x_decompress(comp, inlen, decomp, &outlen, NULL)) |
| 247 | #else |
| 248 | if (av_lzo1x_decode(decomp, &outlen, comp, &inlen)) |
| 249 | #endif |
| 250 | av_log(NULL, AV_LOG_ERROR, "decompression error\n"); |
| 251 | STOP_TIMER("lzod") |
| 252 | } |
| 253 | if (memcmp(orig, decomp, s)) |
| 254 | av_log(NULL, AV_LOG_ERROR, "decompression incorrect\n"); |
| 255 | else |
| 256 | av_log(NULL, AV_LOG_ERROR, "decompression OK\n"); |
| 257 | fclose(in); |
| 258 | return 0; |
| 259 | } |
| 260 | #endif |