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Diffstat (limited to 'src/libFLAC/include/private/bitmath.h')
| -rw-r--r-- | src/libFLAC/include/private/bitmath.h | 210 |
1 files changed, 210 insertions, 0 deletions
diff --git a/src/libFLAC/include/private/bitmath.h b/src/libFLAC/include/private/bitmath.h new file mode 100644 index 0000000..12e062f --- /dev/null +++ b/src/libFLAC/include/private/bitmath.h @@ -0,0 +1,210 @@ +/* libFLAC - Free Lossless Audio Codec library + * Copyright (C) 2001-2009 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. + */ + +#ifndef FLAC__PRIVATE__BITMATH_H +#define FLAC__PRIVATE__BITMATH_H + +#include "FLAC/ordinals.h" +#include "FLAC/assert.h" + +#include "share/compat.h" + +#if defined(_MSC_VER) +#include <intrin.h> /* for _BitScanReverse* */ +#endif + +/* Will never be emitted for MSVC, GCC, Intel compilers */ +static inline uint32_t FLAC__clz_soft_uint32(FLAC__uint32 word) +{ + static const uint8_t byte_to_unary_table[] = { + 8, 7, 6, 6, 5, 5, 5, 5, 4, 4, 4, 4, 4, 4, 4, 4, + 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, + 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, + 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, + 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, + 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, + 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, + 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + }; + + return word > 0xffffff ? byte_to_unary_table[word >> 24] : + word > 0xffff ? byte_to_unary_table[word >> 16] + 8 : + word > 0xff ? byte_to_unary_table[word >> 8] + 16 : + byte_to_unary_table[word] + 24; +} + +static inline uint32_t FLAC__clz_uint32(FLAC__uint32 v) +{ +/* Never used with input 0 */ + FLAC__ASSERT(v > 0); +#if defined(__INTEL_COMPILER) + return _bit_scan_reverse(v) ^ 31U; +#elif defined(__GNUC__) && (__GNUC__ >= 4 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 4)) +/* This will translate either to (bsr ^ 31U), clz , ctlz, cntlz, lzcnt depending on + * -march= setting or to a software routine in exotic machines. */ + return __builtin_clz(v); +#elif defined(_MSC_VER) + { + uint32_t idx; + _BitScanReverse(&idx, v); + return idx ^ 31U; + } +#else + return FLAC__clz_soft_uint32(v); +#endif +} + +/* Used when 64-bit bsr/clz is unavailable; can use 32-bit bsr/clz when possible */ +static inline uint32_t FLAC__clz_soft_uint64(FLAC__uint64 word) +{ + return (FLAC__uint32)(word>>32) ? FLAC__clz_uint32((FLAC__uint32)(word>>32)) : + FLAC__clz_uint32((FLAC__uint32)word) + 32; +} + +static inline uint32_t FLAC__clz_uint64(FLAC__uint64 v) +{ + /* Never used with input 0 */ + FLAC__ASSERT(v > 0); +#if defined(__GNUC__) && (__GNUC__ >= 4 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 4)) + return __builtin_clzll(v); +#elif (defined(__INTEL_COMPILER) || defined(_MSC_VER)) && (defined(_M_IA64) || defined(_M_X64)) + { + uint32_t idx; + _BitScanReverse64(&idx, v); + return idx ^ 63U; + } +#else + return FLAC__clz_soft_uint64(v); +#endif +} + +/* These two functions work with input 0 */ +static inline uint32_t FLAC__clz2_uint32(FLAC__uint32 v) +{ + if (!v) + return 32; + return FLAC__clz_uint32(v); +} + +static inline uint32_t FLAC__clz2_uint64(FLAC__uint64 v) +{ + if (!v) + return 64; + return FLAC__clz_uint64(v); +} + +/* An example of what FLAC__bitmath_ilog2() computes: + * + * ilog2( 0) = assertion failure + * ilog2( 1) = 0 + * ilog2( 2) = 1 + * ilog2( 3) = 1 + * ilog2( 4) = 2 + * ilog2( 5) = 2 + * ilog2( 6) = 2 + * ilog2( 7) = 2 + * ilog2( 8) = 3 + * ilog2( 9) = 3 + * ilog2(10) = 3 + * ilog2(11) = 3 + * ilog2(12) = 3 + * ilog2(13) = 3 + * ilog2(14) = 3 + * ilog2(15) = 3 + * ilog2(16) = 4 + * ilog2(17) = 4 + * ilog2(18) = 4 + */ + +static inline uint32_t FLAC__bitmath_ilog2(FLAC__uint32 v) +{ + FLAC__ASSERT(v > 0); +#if defined(__INTEL_COMPILER) + return _bit_scan_reverse(v); +#elif defined(_MSC_VER) + { + uint32_t idx; + _BitScanReverse(&idx, v); + return idx; + } +#else + return FLAC__clz_uint32(v) ^ 31U; +#endif +} + +static inline uint32_t FLAC__bitmath_ilog2_wide(FLAC__uint64 v) +{ + FLAC__ASSERT(v > 0); +#if defined(__GNUC__) && (__GNUC__ >= 4 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 4)) + return __builtin_clzll(v) ^ 63U; +/* Sorry, only supported in x64/Itanium.. and both have fast FPU which makes integer-only encoder pointless */ +#elif (defined(__INTEL_COMPILER) || defined(_MSC_VER)) && (defined(_M_IA64) || defined(_M_X64)) + { + uint32_t idx; + _BitScanReverse64(&idx, v); + return idx; + } +#else +/* Brain-damaged compilers will use the fastest possible way that is, + de Bruijn sequences (http://supertech.csail.mit.edu/papers/debruijn.pdf) + (C) Timothy B. Terriberry (tterribe@xiph.org) 2001-2009 CC0 (Public domain). +*/ + { + static const uint8_t DEBRUIJN_IDX64[64]={ + 0, 1, 2, 7, 3,13, 8,19, 4,25,14,28, 9,34,20,40, + 5,17,26,38,15,46,29,48,10,31,35,54,21,50,41,57, + 63, 6,12,18,24,27,33,39,16,37,45,47,30,53,49,56, + 62,11,23,32,36,44,52,55,61,22,43,51,60,42,59,58 + }; + v|= v>>1; + v|= v>>2; + v|= v>>4; + v|= v>>8; + v|= v>>16; + v|= v>>32; + v= (v>>1)+1; + return DEBRUIJN_IDX64[v*FLAC__U64L(0x218A392CD3D5DBF)>>58&0x3F]; + } +#endif +} + +uint32_t FLAC__bitmath_silog2(FLAC__int64 v); + +#endif |