/*
  * Copyright (c) 2010 Mans Rullgard <mans@mansr.com>
  *
  * This file is part of FFmpeg.
  *
  * FFmpeg is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *
  * FFmpeg is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with FFmpeg; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
 #ifndef AVUTIL_INTMATH_H
 #define AVUTIL_INTMATH_H
 

 #include <stdint.h>
 

 #include "config.h"

 #include "attributes.h"

 #if ARCH_ARM
 #   include "arm/intmath.h"
 #endif
 

 /**
  * @addtogroup lavu_internal
  * @{
  */
 

 #if   ARCH_ARM
 #   include "arm/intmath.h"
 #endif
 

 #if HAVE_FAST_CLZ && AV_GCC_VERSION_AT_LEAST(3,4)
 

 #ifndef ff_log2
 #   define ff_log2(x) (31 - __builtin_clz((x)|1))
 #   ifndef ff_log2_16bit
 #      define ff_log2_16bit av_log2

 #   endif

 #endif /* ff_log2 */

 
 #endif /* AV_GCC_VERSION_AT_LEAST(3,4) */
 

 extern const uint8_t ff_log2_tab[256];
 
 #ifndef ff_log2
 #define ff_log2 ff_log2_c
 static av_always_inline av_const int ff_log2_c(unsigned int v)
 {
     int n = 0;
     if (v & 0xffff0000) {
         v >>= 16;
         n += 16;
     }
     if (v & 0xff00) {
         v >>= 8;
         n += 8;
     }
     n += ff_log2_tab[v];
 
     return n;
 }
 #endif
 
 #ifndef ff_log2_16bit
 #define ff_log2_16bit ff_log2_16bit_c
 static av_always_inline av_const int ff_log2_16bit_c(unsigned int v)
 {
     int n = 0;
     if (v & 0xff00) {
         v >>= 8;
         n += 8;
     }
     n += ff_log2_tab[v];
 
     return n;
 }
 #endif
 
 #define av_log2       ff_log2
 #define av_log2_16bit ff_log2_16bit
 

 /**
  * @}
  */

 
 /**
  * @addtogroup lavu_math
  * @{
  */
 
 #if HAVE_FAST_CLZ && AV_GCC_VERSION_AT_LEAST(3,4)
 #ifndef ff_ctz
 #define ff_ctz(v) __builtin_ctz(v)
 #endif
 #endif
 
 #ifndef ff_ctz
 #define ff_ctz ff_ctz_c
 static av_always_inline av_const int ff_ctz_c(int v)
 {
     int c;
 
     if (v & 0x1)
         return 0;
 
     c = 1;
     if (!(v & 0xffff)) {
         v >>= 16;
         c += 16;
     }
     if (!(v & 0xff)) {
         v >>= 8;
         c += 8;
     }
     if (!(v & 0xf)) {
         v >>= 4;
         c += 4;
     }
     if (!(v & 0x3)) {
         v >>= 2;
         c += 2;
     }
     c -= v & 0x1;
 
     return c;
 }
 #endif
 
 /**
  * Trailing zero bit count.
  *
  * @param v  input value. If v is 0, the result is undefined.
  * @return   the number of trailing 0-bits
  */
 int av_ctz(int v);
 
 /**
  * @}
  */

 #endif /* AVUTIL_INTMATH_H */