| /* libFLAC - Free Lossless Audio Codec library |
| * Copyright (C) 2001-2009 Josh Coalson |
| * Copyright (C) 2011-2014 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 unsigned int FLAC__clz_soft_uint32(FLAC__uint32 word) |
| { |
| static const unsigned char 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 unsigned int 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) |
| { |
| unsigned long idx; |
| _BitScanReverse(&idx, v); |
| return idx ^ 31U; |
| } |
| #else |
| return FLAC__clz_soft_uint32(v); |
| #endif |
| } |
| |
| /* This one works with input 0 */ |
| static inline unsigned int FLAC__clz2_uint32(FLAC__uint32 v) |
| { |
| if (!v) |
| return 32; |
| return FLAC__clz_uint32(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 unsigned FLAC__bitmath_ilog2(FLAC__uint32 v) |
| { |
| FLAC__ASSERT(v > 0); |
| #if defined(__INTEL_COMPILER) |
| return _bit_scan_reverse(v); |
| #elif defined(_MSC_VER) |
| { |
| unsigned long idx; |
| _BitScanReverse(&idx, v); |
| return idx; |
| } |
| #else |
| return FLAC__clz_uint32(v) ^ 31U; |
| #endif |
| } |
| |
| |
| #ifdef FLAC__INTEGER_ONLY_LIBRARY /* Unused otherwise */ |
| |
| static inline unsigned 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)) |
| { |
| unsigned long 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 unsigned char 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 |
| } |
| #endif |
| |
| unsigned FLAC__bitmath_silog2(int v); |
| unsigned FLAC__bitmath_silog2_wide(FLAC__int64 v); |
| |
| #endif |