/* libFLAC - Free Lossless Audio Codec library

* Copyright (C) 2001-2009 Josh Coalson

* Copyright (C) 2011-2016 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 */

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;

}

{

/* 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)

{

_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 */

{

return (FLAC__uint32)(word>>32) ? FLAC__clz_uint32((FLAC__uint32)(word>>32)) :

FLAC__clz_uint32((FLAC__uint32)word) + 32;

}

{

/* 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))

{

_BitScanReverse64(&idx, v);

return idx ^ 63U;

}

#else

return FLAC__clz_soft_uint64(v);

#endif

}

/* These two functions work with input 0 */

{

if (!v)

return 32;

return FLAC__clz_uint32(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

*/

{

FLAC__ASSERT(v > 0);

#if defined(__INTEL_COMPILER)

return _bit_scan_reverse(v);

#elif defined(_MSC_VER)

{

_BitScanReverse(&idx, v);

return idx;

}

#else

return FLAC__clz_uint32(v) ^ 31U;

#endif

}

{

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))

{

_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).

*/

{

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