mirror of
https://github.com/FFmpeg/FFmpeg.git
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173 lines
3.3 KiB
C
173 lines
3.3 KiB
C
/*
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* Copyright (c) 2010 Mans Rullgard <mans@mansr.com>
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#ifndef AVUTIL_INTMATH_H
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#define AVUTIL_INTMATH_H
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#include <stdint.h>
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#include "config.h"
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#include "attributes.h"
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#if ARCH_ARM
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# include "arm/intmath.h"
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#endif
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#if ARCH_X86
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# include "x86/intmath.h"
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#endif
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#if HAVE_FAST_CLZ
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#if defined( __INTEL_COMPILER )
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#ifndef ff_log2
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# define ff_log2(x) (_bit_scan_reverse((x)|1))
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# ifndef ff_log2_16bit
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# define ff_log2_16bit av_log2
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# endif
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#endif /* ff_log2 */
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#elif AV_GCC_VERSION_AT_LEAST(3,4)
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#ifndef ff_log2
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# define ff_log2(x) (31 - __builtin_clz((x)|1))
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# ifndef ff_log2_16bit
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# define ff_log2_16bit av_log2
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# endif
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#endif /* ff_log2 */
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#endif /* AV_GCC_VERSION_AT_LEAST(3,4) */
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#endif
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extern const uint8_t ff_log2_tab[256];
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#ifndef ff_log2
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#define ff_log2 ff_log2_c
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#if !defined( _MSC_VER )
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static av_always_inline av_const int ff_log2_c(unsigned int v)
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{
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int n = 0;
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if (v & 0xffff0000) {
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v >>= 16;
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n += 16;
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}
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if (v & 0xff00) {
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v >>= 8;
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n += 8;
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}
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n += ff_log2_tab[v];
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return n;
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}
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#else
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static av_always_inline av_const int ff_log2_c(unsigned int v)
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{
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unsigned long n;
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_BitScanReverse(&n, v|1);
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return n;
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}
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#define ff_log2_16bit av_log2
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#endif
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#endif
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#ifndef ff_log2_16bit
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#define ff_log2_16bit ff_log2_16bit_c
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static av_always_inline av_const int ff_log2_16bit_c(unsigned int v)
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{
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int n = 0;
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if (v & 0xff00) {
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v >>= 8;
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n += 8;
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}
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n += ff_log2_tab[v];
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return n;
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}
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#endif
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#define av_log2 ff_log2
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#define av_log2_16bit ff_log2_16bit
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/**
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* @addtogroup lavu_math
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* @{
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*/
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#if HAVE_FAST_CLZ
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#if defined( __INTEL_COMPILER )
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#ifndef ff_ctz
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#define ff_ctz(v) _bit_scan_forward(v)
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#endif
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#elif AV_GCC_VERSION_AT_LEAST(3,4)
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#ifndef ff_ctz
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#define ff_ctz(v) __builtin_ctz(v)
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#endif
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#endif
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#endif
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#ifndef ff_ctz
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#define ff_ctz ff_ctz_c
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#if !defined( _MSC_VER )
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static av_always_inline av_const int ff_ctz_c(int v)
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{
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int c;
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if (v & 0x1)
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return 0;
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c = 1;
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if (!(v & 0xffff)) {
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v >>= 16;
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c += 16;
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}
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if (!(v & 0xff)) {
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v >>= 8;
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c += 8;
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}
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if (!(v & 0xf)) {
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v >>= 4;
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c += 4;
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}
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if (!(v & 0x3)) {
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v >>= 2;
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c += 2;
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}
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c -= v & 0x1;
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return c;
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}
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#else
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static av_always_inline av_const int ff_ctz_c( int v )
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{
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unsigned long c;
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_BitScanForward(&c, v);
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return c;
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}
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#endif
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#endif
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/**
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* Trailing zero bit count.
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*
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* @param v input value. If v is 0, the result is undefined.
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* @return the number of trailing 0-bits
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*/
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int av_ctz(int v);
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/**
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* @}
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*/
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#endif /* AVUTIL_INTMATH_H */
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