Josh Coalson | f719813 | 2004-11-09 01:25:14 +0000 | [diff] [blame] | 1 | /* libFLAC - Free Lossless Audio Codec library |
Josh Coalson | 0395dac | 2006-04-25 06:59:33 +0000 | [diff] [blame] | 2 | * Copyright (C) 2004,2005,2006 Josh Coalson |
Josh Coalson | f719813 | 2004-11-09 01:25:14 +0000 | [diff] [blame] | 3 | * |
| 4 | * Redistribution and use in source and binary forms, with or without |
| 5 | * modification, are permitted provided that the following conditions |
| 6 | * are met: |
| 7 | * |
| 8 | * - Redistributions of source code must retain the above copyright |
| 9 | * notice, this list of conditions and the following disclaimer. |
| 10 | * |
| 11 | * - Redistributions in binary form must reproduce the above copyright |
| 12 | * notice, this list of conditions and the following disclaimer in the |
| 13 | * documentation and/or other materials provided with the distribution. |
| 14 | * |
| 15 | * - Neither the name of the Xiph.org Foundation nor the names of its |
| 16 | * contributors may be used to endorse or promote products derived from |
| 17 | * this software without specific prior written permission. |
| 18 | * |
| 19 | * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| 20 | * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| 21 | * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| 22 | * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR |
| 23 | * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, |
| 24 | * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, |
| 25 | * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR |
| 26 | * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF |
| 27 | * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING |
| 28 | * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS |
| 29 | * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| 30 | */ |
| 31 | |
Josh Coalson | b1ec796 | 2006-05-24 04:41:36 +0000 | [diff] [blame^] | 32 | #if HAVE_CONFIG_H |
| 33 | # include <config.h> |
| 34 | #endif |
| 35 | |
Josh Coalson | f719813 | 2004-11-09 01:25:14 +0000 | [diff] [blame] | 36 | #include "FLAC/assert.h" |
| 37 | |
| 38 | #include "private/float.h" |
| 39 | |
| 40 | #ifdef FLAC__INTEGER_ONLY_LIBRARY |
| 41 | |
| 42 | /* adjust for compilers that can't understand using LLU suffix for uint64_t literals */ |
| 43 | #ifdef _MSC_VER |
| 44 | #define FLAC__U64L(x) x |
| 45 | #else |
| 46 | #define FLAC__U64L(x) x##LLU |
| 47 | #endif |
| 48 | |
| 49 | const FLAC__fixedpoint FLAC__FP_ZERO = 0; |
| 50 | const FLAC__fixedpoint FLAC__FP_ONE_HALF = 0x00008000; |
| 51 | const FLAC__fixedpoint FLAC__FP_ONE = 0x00010000; |
| 52 | const FLAC__fixedpoint FLAC__FP_LN2 = 45426; |
| 53 | const FLAC__fixedpoint FLAC__FP_E = 178145; |
| 54 | |
| 55 | /* Lookup tables for Knuth's logarithm algorithm */ |
| 56 | #define LOG2_LOOKUP_PRECISION 16 |
| 57 | static const FLAC__uint32 log2_lookup[][LOG2_LOOKUP_PRECISION] = { |
| 58 | { |
| 59 | /* |
| 60 | * 0 fraction bits |
| 61 | */ |
| 62 | /* undefined */ 0x00000000, |
| 63 | /* lg(2/1) = */ 0x00000001, |
| 64 | /* lg(4/3) = */ 0x00000000, |
| 65 | /* lg(8/7) = */ 0x00000000, |
| 66 | /* lg(16/15) = */ 0x00000000, |
| 67 | /* lg(32/31) = */ 0x00000000, |
| 68 | /* lg(64/63) = */ 0x00000000, |
| 69 | /* lg(128/127) = */ 0x00000000, |
| 70 | /* lg(256/255) = */ 0x00000000, |
| 71 | /* lg(512/511) = */ 0x00000000, |
| 72 | /* lg(1024/1023) = */ 0x00000000, |
| 73 | /* lg(2048/2047) = */ 0x00000000, |
| 74 | /* lg(4096/4095) = */ 0x00000000, |
| 75 | /* lg(8192/8191) = */ 0x00000000, |
| 76 | /* lg(16384/16383) = */ 0x00000000, |
| 77 | /* lg(32768/32767) = */ 0x00000000 |
| 78 | }, |
| 79 | { |
| 80 | /* |
| 81 | * 4 fraction bits |
| 82 | */ |
| 83 | /* undefined */ 0x00000000, |
| 84 | /* lg(2/1) = */ 0x00000010, |
| 85 | /* lg(4/3) = */ 0x00000007, |
| 86 | /* lg(8/7) = */ 0x00000003, |
| 87 | /* lg(16/15) = */ 0x00000001, |
| 88 | /* lg(32/31) = */ 0x00000001, |
| 89 | /* lg(64/63) = */ 0x00000000, |
| 90 | /* lg(128/127) = */ 0x00000000, |
| 91 | /* lg(256/255) = */ 0x00000000, |
| 92 | /* lg(512/511) = */ 0x00000000, |
| 93 | /* lg(1024/1023) = */ 0x00000000, |
| 94 | /* lg(2048/2047) = */ 0x00000000, |
| 95 | /* lg(4096/4095) = */ 0x00000000, |
| 96 | /* lg(8192/8191) = */ 0x00000000, |
| 97 | /* lg(16384/16383) = */ 0x00000000, |
| 98 | /* lg(32768/32767) = */ 0x00000000 |
| 99 | }, |
| 100 | { |
| 101 | /* |
| 102 | * 8 fraction bits |
| 103 | */ |
| 104 | /* undefined */ 0x00000000, |
| 105 | /* lg(2/1) = */ 0x00000100, |
| 106 | /* lg(4/3) = */ 0x0000006a, |
| 107 | /* lg(8/7) = */ 0x00000031, |
| 108 | /* lg(16/15) = */ 0x00000018, |
| 109 | /* lg(32/31) = */ 0x0000000c, |
| 110 | /* lg(64/63) = */ 0x00000006, |
| 111 | /* lg(128/127) = */ 0x00000003, |
| 112 | /* lg(256/255) = */ 0x00000001, |
| 113 | /* lg(512/511) = */ 0x00000001, |
| 114 | /* lg(1024/1023) = */ 0x00000000, |
| 115 | /* lg(2048/2047) = */ 0x00000000, |
| 116 | /* lg(4096/4095) = */ 0x00000000, |
| 117 | /* lg(8192/8191) = */ 0x00000000, |
| 118 | /* lg(16384/16383) = */ 0x00000000, |
| 119 | /* lg(32768/32767) = */ 0x00000000 |
| 120 | }, |
| 121 | { |
| 122 | /* |
| 123 | * 12 fraction bits |
| 124 | */ |
| 125 | /* undefined */ 0x00000000, |
| 126 | /* lg(2/1) = */ 0x00001000, |
| 127 | /* lg(4/3) = */ 0x000006a4, |
| 128 | /* lg(8/7) = */ 0x00000315, |
| 129 | /* lg(16/15) = */ 0x0000017d, |
| 130 | /* lg(32/31) = */ 0x000000bc, |
| 131 | /* lg(64/63) = */ 0x0000005d, |
| 132 | /* lg(128/127) = */ 0x0000002e, |
| 133 | /* lg(256/255) = */ 0x00000017, |
| 134 | /* lg(512/511) = */ 0x0000000c, |
| 135 | /* lg(1024/1023) = */ 0x00000006, |
| 136 | /* lg(2048/2047) = */ 0x00000003, |
| 137 | /* lg(4096/4095) = */ 0x00000001, |
| 138 | /* lg(8192/8191) = */ 0x00000001, |
| 139 | /* lg(16384/16383) = */ 0x00000000, |
| 140 | /* lg(32768/32767) = */ 0x00000000 |
| 141 | }, |
| 142 | { |
| 143 | /* |
| 144 | * 16 fraction bits |
| 145 | */ |
| 146 | /* undefined */ 0x00000000, |
| 147 | /* lg(2/1) = */ 0x00010000, |
| 148 | /* lg(4/3) = */ 0x00006a40, |
| 149 | /* lg(8/7) = */ 0x00003151, |
| 150 | /* lg(16/15) = */ 0x000017d6, |
| 151 | /* lg(32/31) = */ 0x00000bba, |
| 152 | /* lg(64/63) = */ 0x000005d1, |
| 153 | /* lg(128/127) = */ 0x000002e6, |
| 154 | /* lg(256/255) = */ 0x00000172, |
| 155 | /* lg(512/511) = */ 0x000000b9, |
| 156 | /* lg(1024/1023) = */ 0x0000005c, |
| 157 | /* lg(2048/2047) = */ 0x0000002e, |
| 158 | /* lg(4096/4095) = */ 0x00000017, |
| 159 | /* lg(8192/8191) = */ 0x0000000c, |
| 160 | /* lg(16384/16383) = */ 0x00000006, |
| 161 | /* lg(32768/32767) = */ 0x00000003 |
| 162 | }, |
| 163 | { |
| 164 | /* |
| 165 | * 20 fraction bits |
| 166 | */ |
| 167 | /* undefined */ 0x00000000, |
| 168 | /* lg(2/1) = */ 0x00100000, |
| 169 | /* lg(4/3) = */ 0x0006a3fe, |
| 170 | /* lg(8/7) = */ 0x00031513, |
| 171 | /* lg(16/15) = */ 0x00017d60, |
| 172 | /* lg(32/31) = */ 0x0000bb9d, |
| 173 | /* lg(64/63) = */ 0x00005d10, |
| 174 | /* lg(128/127) = */ 0x00002e59, |
| 175 | /* lg(256/255) = */ 0x00001721, |
| 176 | /* lg(512/511) = */ 0x00000b8e, |
| 177 | /* lg(1024/1023) = */ 0x000005c6, |
| 178 | /* lg(2048/2047) = */ 0x000002e3, |
| 179 | /* lg(4096/4095) = */ 0x00000171, |
| 180 | /* lg(8192/8191) = */ 0x000000b9, |
| 181 | /* lg(16384/16383) = */ 0x0000005c, |
| 182 | /* lg(32768/32767) = */ 0x0000002e |
| 183 | }, |
| 184 | { |
| 185 | /* |
| 186 | * 24 fraction bits |
| 187 | */ |
| 188 | /* undefined */ 0x00000000, |
| 189 | /* lg(2/1) = */ 0x01000000, |
| 190 | /* lg(4/3) = */ 0x006a3fe6, |
| 191 | /* lg(8/7) = */ 0x00315130, |
| 192 | /* lg(16/15) = */ 0x0017d605, |
| 193 | /* lg(32/31) = */ 0x000bb9ca, |
| 194 | /* lg(64/63) = */ 0x0005d0fc, |
| 195 | /* lg(128/127) = */ 0x0002e58f, |
| 196 | /* lg(256/255) = */ 0x0001720e, |
| 197 | /* lg(512/511) = */ 0x0000b8d8, |
| 198 | /* lg(1024/1023) = */ 0x00005c61, |
| 199 | /* lg(2048/2047) = */ 0x00002e2d, |
| 200 | /* lg(4096/4095) = */ 0x00001716, |
| 201 | /* lg(8192/8191) = */ 0x00000b8b, |
| 202 | /* lg(16384/16383) = */ 0x000005c5, |
| 203 | /* lg(32768/32767) = */ 0x000002e3 |
| 204 | }, |
| 205 | { |
| 206 | /* |
| 207 | * 28 fraction bits |
| 208 | */ |
| 209 | /* undefined */ 0x00000000, |
| 210 | /* lg(2/1) = */ 0x10000000, |
| 211 | /* lg(4/3) = */ 0x06a3fe5c, |
| 212 | /* lg(8/7) = */ 0x03151301, |
| 213 | /* lg(16/15) = */ 0x017d6049, |
| 214 | /* lg(32/31) = */ 0x00bb9ca6, |
| 215 | /* lg(64/63) = */ 0x005d0fba, |
| 216 | /* lg(128/127) = */ 0x002e58f7, |
| 217 | /* lg(256/255) = */ 0x001720da, |
| 218 | /* lg(512/511) = */ 0x000b8d87, |
| 219 | /* lg(1024/1023) = */ 0x0005c60b, |
| 220 | /* lg(2048/2047) = */ 0x0002e2d7, |
| 221 | /* lg(4096/4095) = */ 0x00017160, |
| 222 | /* lg(8192/8191) = */ 0x0000b8ad, |
| 223 | /* lg(16384/16383) = */ 0x00005c56, |
| 224 | /* lg(32768/32767) = */ 0x00002e2b |
| 225 | } |
| 226 | }; |
| 227 | |
| 228 | #if 0 |
| 229 | static const FLAC__uint64 log2_lookup_wide[] = { |
| 230 | { |
| 231 | /* |
| 232 | * 32 fraction bits |
| 233 | */ |
| 234 | /* undefined */ 0x00000000, |
| 235 | /* lg(2/1) = */ FLAC__U64L(0x100000000), |
| 236 | /* lg(4/3) = */ FLAC__U64L(0x6a3fe5c6), |
| 237 | /* lg(8/7) = */ FLAC__U64L(0x31513015), |
| 238 | /* lg(16/15) = */ FLAC__U64L(0x17d60497), |
| 239 | /* lg(32/31) = */ FLAC__U64L(0x0bb9ca65), |
| 240 | /* lg(64/63) = */ FLAC__U64L(0x05d0fba2), |
| 241 | /* lg(128/127) = */ FLAC__U64L(0x02e58f74), |
| 242 | /* lg(256/255) = */ FLAC__U64L(0x01720d9c), |
| 243 | /* lg(512/511) = */ FLAC__U64L(0x00b8d875), |
| 244 | /* lg(1024/1023) = */ FLAC__U64L(0x005c60aa), |
| 245 | /* lg(2048/2047) = */ FLAC__U64L(0x002e2d72), |
| 246 | /* lg(4096/4095) = */ FLAC__U64L(0x00171600), |
| 247 | /* lg(8192/8191) = */ FLAC__U64L(0x000b8ad2), |
| 248 | /* lg(16384/16383) = */ FLAC__U64L(0x0005c55d), |
| 249 | /* lg(32768/32767) = */ FLAC__U64L(0x0002e2ac) |
| 250 | }, |
| 251 | { |
| 252 | /* |
| 253 | * 48 fraction bits |
| 254 | */ |
| 255 | /* undefined */ 0x00000000, |
| 256 | /* lg(2/1) = */ FLAC__U64L(0x1000000000000), |
| 257 | /* lg(4/3) = */ FLAC__U64L(0x6a3fe5c60429), |
| 258 | /* lg(8/7) = */ FLAC__U64L(0x315130157f7a), |
| 259 | /* lg(16/15) = */ FLAC__U64L(0x17d60496cfbb), |
| 260 | /* lg(32/31) = */ FLAC__U64L(0xbb9ca64ecac), |
| 261 | /* lg(64/63) = */ FLAC__U64L(0x5d0fba187cd), |
| 262 | /* lg(128/127) = */ FLAC__U64L(0x2e58f7441ee), |
| 263 | /* lg(256/255) = */ FLAC__U64L(0x1720d9c06a8), |
| 264 | /* lg(512/511) = */ FLAC__U64L(0xb8d8752173), |
| 265 | /* lg(1024/1023) = */ FLAC__U64L(0x5c60aa252e), |
| 266 | /* lg(2048/2047) = */ FLAC__U64L(0x2e2d71b0d8), |
| 267 | /* lg(4096/4095) = */ FLAC__U64L(0x1716001719), |
| 268 | /* lg(8192/8191) = */ FLAC__U64L(0xb8ad1de1b), |
| 269 | /* lg(16384/16383) = */ FLAC__U64L(0x5c55d640d), |
| 270 | /* lg(32768/32767) = */ FLAC__U64L(0x2e2abcf52) |
| 271 | } |
| 272 | }; |
| 273 | #endif |
| 274 | |
| 275 | FLAC__uint32 FLAC__fixedpoint_log2(FLAC__uint32 x, unsigned fracbits, unsigned precision) |
| 276 | { |
| 277 | const FLAC__uint32 ONE = (1u << fracbits); |
| 278 | const FLAC__uint32 *table = log2_lookup[fracbits >> 2]; |
| 279 | |
| 280 | FLAC__ASSERT(fracbits < 32); |
| 281 | FLAC__ASSERT((fracbits & 0x3) == 0); |
| 282 | |
| 283 | if(x < ONE) |
| 284 | return 0; |
| 285 | |
| 286 | if(precision > LOG2_LOOKUP_PRECISION) |
| 287 | precision = LOG2_LOOKUP_PRECISION; |
| 288 | |
| 289 | /* Knuth's algorithm for computing logarithms, optimized for base-2 with lookup tables */ |
| 290 | { |
| 291 | FLAC__uint32 y = 0; |
| 292 | FLAC__uint32 z = x >> 1, k = 1; |
| 293 | while (x > ONE && k < precision) { |
| 294 | if (x - z >= ONE) { |
| 295 | x -= z; |
| 296 | z = x >> k; |
| 297 | y += table[k]; |
| 298 | } |
| 299 | else { |
| 300 | z >>= 1; |
| 301 | k++; |
| 302 | } |
| 303 | } |
| 304 | return y; |
| 305 | } |
| 306 | } |
| 307 | |
| 308 | #endif /* defined FLAC__INTEGER_ONLY_LIBRARY */ |