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Diffstat (limited to 'src/libFLAC/float.c')
| -rw-r--r-- | src/libFLAC/float.c | 302 |
1 files changed, 302 insertions, 0 deletions
diff --git a/src/libFLAC/float.c b/src/libFLAC/float.c new file mode 100644 index 0000000..a06ad28 --- /dev/null +++ b/src/libFLAC/float.c @@ -0,0 +1,302 @@ +/* libFLAC - Free Lossless Audio Codec library + * Copyright (C) 2004-2009 Josh Coalson + * Copyright (C) 2011-2023 Xiph.Org Foundation + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * - Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * + * - Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * - Neither the name of the Xiph.org Foundation nor the names of its + * contributors may be used to endorse or promote products derived from + * this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR + * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR + * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, + * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, + * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR + * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF + * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING + * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS + * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +#ifdef HAVE_CONFIG_H +# include <config.h> +#endif + +#include "FLAC/assert.h" +#include "share/compat.h" +#include "private/float.h" + +#ifdef FLAC__INTEGER_ONLY_LIBRARY + +const FLAC__fixedpoint FLAC__FP_ZERO = 0; +const FLAC__fixedpoint FLAC__FP_ONE_HALF = 0x00008000; +const FLAC__fixedpoint FLAC__FP_ONE = 0x00010000; +const FLAC__fixedpoint FLAC__FP_LN2 = 45426; +const FLAC__fixedpoint FLAC__FP_E = 178145; + +/* Lookup tables for Knuth's logarithm algorithm */ +#define LOG2_LOOKUP_PRECISION 16 +static const FLAC__uint32 log2_lookup[][LOG2_LOOKUP_PRECISION] = { + { + /* + * 0 fraction bits + */ + /* undefined */ 0x00000000, + /* lg(2/1) = */ 0x00000001, + /* lg(4/3) = */ 0x00000000, + /* lg(8/7) = */ 0x00000000, + /* lg(16/15) = */ 0x00000000, + /* lg(32/31) = */ 0x00000000, + /* lg(64/63) = */ 0x00000000, + /* lg(128/127) = */ 0x00000000, + /* lg(256/255) = */ 0x00000000, + /* lg(512/511) = */ 0x00000000, + /* lg(1024/1023) = */ 0x00000000, + /* lg(2048/2047) = */ 0x00000000, + /* lg(4096/4095) = */ 0x00000000, + /* lg(8192/8191) = */ 0x00000000, + /* lg(16384/16383) = */ 0x00000000, + /* lg(32768/32767) = */ 0x00000000 + }, + { + /* + * 4 fraction bits + */ + /* undefined */ 0x00000000, + /* lg(2/1) = */ 0x00000010, + /* lg(4/3) = */ 0x00000007, + /* lg(8/7) = */ 0x00000003, + /* lg(16/15) = */ 0x00000001, + /* lg(32/31) = */ 0x00000001, + /* lg(64/63) = */ 0x00000000, + /* lg(128/127) = */ 0x00000000, + /* lg(256/255) = */ 0x00000000, + /* lg(512/511) = */ 0x00000000, + /* lg(1024/1023) = */ 0x00000000, + /* lg(2048/2047) = */ 0x00000000, + /* lg(4096/4095) = */ 0x00000000, + /* lg(8192/8191) = */ 0x00000000, + /* lg(16384/16383) = */ 0x00000000, + /* lg(32768/32767) = */ 0x00000000 + }, + { + /* + * 8 fraction bits + */ + /* undefined */ 0x00000000, + /* lg(2/1) = */ 0x00000100, + /* lg(4/3) = */ 0x0000006a, + /* lg(8/7) = */ 0x00000031, + /* lg(16/15) = */ 0x00000018, + /* lg(32/31) = */ 0x0000000c, + /* lg(64/63) = */ 0x00000006, + /* lg(128/127) = */ 0x00000003, + /* lg(256/255) = */ 0x00000001, + /* lg(512/511) = */ 0x00000001, + /* lg(1024/1023) = */ 0x00000000, + /* lg(2048/2047) = */ 0x00000000, + /* lg(4096/4095) = */ 0x00000000, + /* lg(8192/8191) = */ 0x00000000, + /* lg(16384/16383) = */ 0x00000000, + /* lg(32768/32767) = */ 0x00000000 + }, + { + /* + * 12 fraction bits + */ + /* undefined */ 0x00000000, + /* lg(2/1) = */ 0x00001000, + /* lg(4/3) = */ 0x000006a4, + /* lg(8/7) = */ 0x00000315, + /* lg(16/15) = */ 0x0000017d, + /* lg(32/31) = */ 0x000000bc, + /* lg(64/63) = */ 0x0000005d, + /* lg(128/127) = */ 0x0000002e, + /* lg(256/255) = */ 0x00000017, + /* lg(512/511) = */ 0x0000000c, + /* lg(1024/1023) = */ 0x00000006, + /* lg(2048/2047) = */ 0x00000003, + /* lg(4096/4095) = */ 0x00000001, + /* lg(8192/8191) = */ 0x00000001, + /* lg(16384/16383) = */ 0x00000000, + /* lg(32768/32767) = */ 0x00000000 + }, + { + /* + * 16 fraction bits + */ + /* undefined */ 0x00000000, + /* lg(2/1) = */ 0x00010000, + /* lg(4/3) = */ 0x00006a40, + /* lg(8/7) = */ 0x00003151, + /* lg(16/15) = */ 0x000017d6, + /* lg(32/31) = */ 0x00000bba, + /* lg(64/63) = */ 0x000005d1, + /* lg(128/127) = */ 0x000002e6, + /* lg(256/255) = */ 0x00000172, + /* lg(512/511) = */ 0x000000b9, + /* lg(1024/1023) = */ 0x0000005c, + /* lg(2048/2047) = */ 0x0000002e, + /* lg(4096/4095) = */ 0x00000017, + /* lg(8192/8191) = */ 0x0000000c, + /* lg(16384/16383) = */ 0x00000006, + /* lg(32768/32767) = */ 0x00000003 + }, + { + /* + * 20 fraction bits + */ + /* undefined */ 0x00000000, + /* lg(2/1) = */ 0x00100000, + /* lg(4/3) = */ 0x0006a3fe, + /* lg(8/7) = */ 0x00031513, + /* lg(16/15) = */ 0x00017d60, + /* lg(32/31) = */ 0x0000bb9d, + /* lg(64/63) = */ 0x00005d10, + /* lg(128/127) = */ 0x00002e59, + /* lg(256/255) = */ 0x00001721, + /* lg(512/511) = */ 0x00000b8e, + /* lg(1024/1023) = */ 0x000005c6, + /* lg(2048/2047) = */ 0x000002e3, + /* lg(4096/4095) = */ 0x00000171, + /* lg(8192/8191) = */ 0x000000b9, + /* lg(16384/16383) = */ 0x0000005c, + /* lg(32768/32767) = */ 0x0000002e + }, + { + /* + * 24 fraction bits + */ + /* undefined */ 0x00000000, + /* lg(2/1) = */ 0x01000000, + /* lg(4/3) = */ 0x006a3fe6, + /* lg(8/7) = */ 0x00315130, + /* lg(16/15) = */ 0x0017d605, + /* lg(32/31) = */ 0x000bb9ca, + /* lg(64/63) = */ 0x0005d0fc, + /* lg(128/127) = */ 0x0002e58f, + /* lg(256/255) = */ 0x0001720e, + /* lg(512/511) = */ 0x0000b8d8, + /* lg(1024/1023) = */ 0x00005c61, + /* lg(2048/2047) = */ 0x00002e2d, + /* lg(4096/4095) = */ 0x00001716, + /* lg(8192/8191) = */ 0x00000b8b, + /* lg(16384/16383) = */ 0x000005c5, + /* lg(32768/32767) = */ 0x000002e3 + }, + { + /* + * 28 fraction bits + */ + /* undefined */ 0x00000000, + /* lg(2/1) = */ 0x10000000, + /* lg(4/3) = */ 0x06a3fe5c, + /* lg(8/7) = */ 0x03151301, + /* lg(16/15) = */ 0x017d6049, + /* lg(32/31) = */ 0x00bb9ca6, + /* lg(64/63) = */ 0x005d0fba, + /* lg(128/127) = */ 0x002e58f7, + /* lg(256/255) = */ 0x001720da, + /* lg(512/511) = */ 0x000b8d87, + /* lg(1024/1023) = */ 0x0005c60b, + /* lg(2048/2047) = */ 0x0002e2d7, + /* lg(4096/4095) = */ 0x00017160, + /* lg(8192/8191) = */ 0x0000b8ad, + /* lg(16384/16383) = */ 0x00005c56, + /* lg(32768/32767) = */ 0x00002e2b + } +}; + +#if 0 +static const FLAC__uint64 log2_lookup_wide[] = { + { + /* + * 32 fraction bits + */ + /* undefined */ 0x00000000, + /* lg(2/1) = */ FLAC__U64L(0x100000000), + /* lg(4/3) = */ FLAC__U64L(0x6a3fe5c6), + /* lg(8/7) = */ FLAC__U64L(0x31513015), + /* lg(16/15) = */ FLAC__U64L(0x17d60497), + /* lg(32/31) = */ FLAC__U64L(0x0bb9ca65), + /* lg(64/63) = */ FLAC__U64L(0x05d0fba2), + /* lg(128/127) = */ FLAC__U64L(0x02e58f74), + /* lg(256/255) = */ FLAC__U64L(0x01720d9c), + /* lg(512/511) = */ FLAC__U64L(0x00b8d875), + /* lg(1024/1023) = */ FLAC__U64L(0x005c60aa), + /* lg(2048/2047) = */ FLAC__U64L(0x002e2d72), + /* lg(4096/4095) = */ FLAC__U64L(0x00171600), + /* lg(8192/8191) = */ FLAC__U64L(0x000b8ad2), + /* lg(16384/16383) = */ FLAC__U64L(0x0005c55d), + /* lg(32768/32767) = */ FLAC__U64L(0x0002e2ac) + }, + { + /* + * 48 fraction bits + */ + /* undefined */ 0x00000000, + /* lg(2/1) = */ FLAC__U64L(0x1000000000000), + /* lg(4/3) = */ FLAC__U64L(0x6a3fe5c60429), + /* lg(8/7) = */ FLAC__U64L(0x315130157f7a), + /* lg(16/15) = */ FLAC__U64L(0x17d60496cfbb), + /* lg(32/31) = */ FLAC__U64L(0xbb9ca64ecac), + /* lg(64/63) = */ FLAC__U64L(0x5d0fba187cd), + /* lg(128/127) = */ FLAC__U64L(0x2e58f7441ee), + /* lg(256/255) = */ FLAC__U64L(0x1720d9c06a8), + /* lg(512/511) = */ FLAC__U64L(0xb8d8752173), + /* lg(1024/1023) = */ FLAC__U64L(0x5c60aa252e), + /* lg(2048/2047) = */ FLAC__U64L(0x2e2d71b0d8), + /* lg(4096/4095) = */ FLAC__U64L(0x1716001719), + /* lg(8192/8191) = */ FLAC__U64L(0xb8ad1de1b), + /* lg(16384/16383) = */ FLAC__U64L(0x5c55d640d), + /* lg(32768/32767) = */ FLAC__U64L(0x2e2abcf52) + } +}; +#endif + +FLAC__uint32 FLAC__fixedpoint_log2(FLAC__uint32 x, uint32_t fracbits, uint32_t precision) +{ + const FLAC__uint32 ONE = (1u << fracbits); + const FLAC__uint32 *table = log2_lookup[fracbits >> 2]; + + FLAC__ASSERT(fracbits < 32); + FLAC__ASSERT((fracbits & 0x3) == 0); + + if(x < ONE) + return 0; + + if(precision > LOG2_LOOKUP_PRECISION) + precision = LOG2_LOOKUP_PRECISION; + + /* Knuth's algorithm for computing logarithms, optimized for base-2 with lookup tables */ + { + FLAC__uint32 y = 0; + FLAC__uint32 z = x >> 1, k = 1; + while (x > ONE && k < precision) { + if (x - z >= ONE) { + x -= z; + z = x >> k; + y += table[k]; + } + else { + z >>= 1; + k++; + } + } + return y; + } +} + +#endif /* defined FLAC__INTEGER_ONLY_LIBRARY */ |