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FFmpeg/libavutil/common.h
Nicolas George f16c950f32 lavu: document av_reverse.
2012-02-22 15:35:44 +01:00

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/*
* copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at>
*
* 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
*/
/**
* @file
* common internal and external API header
*/
#ifndef AVUTIL_COMMON_H
#define AVUTIL_COMMON_H
#include <ctype.h>
#include <errno.h>
#include <inttypes.h>
#include <limits.h>
#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "attributes.h"
#include "libavutil/avconfig.h"
#if AV_HAVE_BIGENDIAN
# define AV_NE(be, le) (be)
#else
# define AV_NE(be, le) (le)
#endif
//rounded division & shift
#define RSHIFT(a,b) ((a) > 0 ? ((a) + ((1<<(b))>>1))>>(b) : ((a) + ((1<<(b))>>1)-1)>>(b))
/* assume b>0 */
#define ROUNDED_DIV(a,b) (((a)>0 ? (a) + ((b)>>1) : (a) - ((b)>>1))/(b))
#define FFUDIV(a,b) (((a)>0 ?(a):(a)-(b)+1) / (b))
#define FFUMOD(a,b) ((a)-(b)*FFUDIV(a,b))
#define FFABS(a) ((a) >= 0 ? (a) : (-(a)))
#define FFSIGN(a) ((a) > 0 ? 1 : -1)
#define FFMAX(a,b) ((a) > (b) ? (a) : (b))
#define FFMAX3(a,b,c) FFMAX(FFMAX(a,b),c)
#define FFMIN(a,b) ((a) > (b) ? (b) : (a))
#define FFMIN3(a,b,c) FFMIN(FFMIN(a,b),c)
#define FFSWAP(type,a,b) do{type SWAP_tmp= b; b= a; a= SWAP_tmp;}while(0)
#define FF_ARRAY_ELEMS(a) (sizeof(a) / sizeof((a)[0]))
#define FFALIGN(x, a) (((x)+(a)-1)&~((a)-1))
/* misc math functions */
extern const uint8_t ff_log2_tab[256];
/**
* Reverse the order of the bits of an 8-bits unsigned integer.
*/
extern const uint8_t av_reverse[256];
static av_always_inline av_const int av_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;
}
static av_always_inline av_const int av_log2_16bit_c(unsigned int v)
{
int n = 0;
if (v & 0xff00) {
v >>= 8;
n += 8;
}
n += ff_log2_tab[v];
return n;
}
#ifdef HAVE_AV_CONFIG_H
# include "config.h"
# include "intmath.h"
#endif
/* Pull in unguarded fallback defines at the end of this file. */
#include "common.h"
/**
* Clip a signed integer value into the amin-amax range.
* @param a value to clip
* @param amin minimum value of the clip range
* @param amax maximum value of the clip range
* @return clipped value
*/
static av_always_inline av_const int av_clip_c(int a, int amin, int amax)
{
if (a < amin) return amin;
else if (a > amax) return amax;
else return a;
}
/**
* Clip a signed integer value into the 0-255 range.
* @param a value to clip
* @return clipped value
*/
static av_always_inline av_const uint8_t av_clip_uint8_c(int a)
{
if (a&(~0xFF)) return (-a)>>31;
else return a;
}
/**
* Clip a signed integer value into the -128,127 range.
* @param a value to clip
* @return clipped value
*/
static av_always_inline av_const int8_t av_clip_int8_c(int a)
{
if ((a+0x80) & ~0xFF) return (a>>31) ^ 0x7F;
else return a;
}
/**
* Clip a signed integer value into the 0-65535 range.
* @param a value to clip
* @return clipped value
*/
static av_always_inline av_const uint16_t av_clip_uint16_c(int a)
{
if (a&(~0xFFFF)) return (-a)>>31;
else return a;
}
/**
* Clip a signed integer value into the -32768,32767 range.
* @param a value to clip
* @return clipped value
*/
static av_always_inline av_const int16_t av_clip_int16_c(int a)
{
if ((a+0x8000) & ~0xFFFF) return (a>>31) ^ 0x7FFF;
else return a;
}
/**
* Clip a signed 64-bit integer value into the -2147483648,2147483647 range.
* @param a value to clip
* @return clipped value
*/
static av_always_inline av_const int32_t av_clipl_int32_c(int64_t a)
{
if ((a+0x80000000u) & ~UINT64_C(0xFFFFFFFF)) return (a>>63) ^ 0x7FFFFFFF;
else return a;
}
/**
* Clip a signed integer to an unsigned power of two range.
* @param a value to clip
* @param p bit position to clip at
* @return clipped value
*/
static av_always_inline av_const unsigned av_clip_uintp2_c(int a, int p)
{
if (a & ~((1<<p) - 1)) return -a >> 31 & ((1<<p) - 1);
else return a;
}
/**
* Clip a float value into the amin-amax range.
* @param a value to clip
* @param amin minimum value of the clip range
* @param amax maximum value of the clip range
* @return clipped value
*/
static av_always_inline av_const float av_clipf_c(float a, float amin, float amax)
{
if (a < amin) return amin;
else if (a > amax) return amax;
else return a;
}
/** Compute ceil(log2(x)).
* @param x value used to compute ceil(log2(x))
* @return computed ceiling of log2(x)
*/
static av_always_inline av_const int av_ceil_log2_c(int x)
{
return av_log2((x - 1) << 1);
}
/**
* Count number of bits set to one in x
* @param x value to count bits of
* @return the number of bits set to one in x
*/
static av_always_inline av_const int av_popcount_c(uint32_t x)
{
x -= (x >> 1) & 0x55555555;
x = (x & 0x33333333) + ((x >> 2) & 0x33333333);
x = (x + (x >> 4)) & 0x0F0F0F0F;
x += x >> 8;
return (x + (x >> 16)) & 0x3F;
}
/**
* Count number of bits set to one in x
* @param x value to count bits of
* @return the number of bits set to one in x
*/
static av_always_inline av_const int av_popcount64_c(uint64_t x)
{
return av_popcount(x) + av_popcount(x >> 32);
}
#define MKTAG(a,b,c,d) ((a) | ((b) << 8) | ((c) << 16) | ((unsigned)(d) << 24))
#define MKBETAG(a,b,c,d) ((d) | ((c) << 8) | ((b) << 16) | ((unsigned)(a) << 24))
/**
* Convert a UTF-8 character (up to 4 bytes) to its 32-bit UCS-4 encoded form.
*
* @param val Output value, must be an lvalue of type uint32_t.
* @param GET_BYTE Expression reading one byte from the input.
* Evaluated up to 7 times (4 for the currently
* assigned Unicode range). With a memory buffer
* input, this could be *ptr++.
* @param ERROR Expression to be evaluated on invalid input,
* typically a goto statement.
*/
#define GET_UTF8(val, GET_BYTE, ERROR)\
val= GET_BYTE;\
{\
int ones= 7 - av_log2(val ^ 255);\
if(ones==1)\
ERROR\
val&= 127>>ones;\
while(--ones > 0){\
int tmp= GET_BYTE - 128;\
if(tmp>>6)\
ERROR\
val= (val<<6) + tmp;\
}\
}
/**
* Convert a UTF-16 character (2 or 4 bytes) to its 32-bit UCS-4 encoded form.
*
* @param val Output value, must be an lvalue of type uint32_t.
* @param GET_16BIT Expression returning two bytes of UTF-16 data converted
* to native byte order. Evaluated one or two times.
* @param ERROR Expression to be evaluated on invalid input,
* typically a goto statement.
*/
#define GET_UTF16(val, GET_16BIT, ERROR)\
val = GET_16BIT;\
{\
unsigned int hi = val - 0xD800;\
if (hi < 0x800) {\
val = GET_16BIT - 0xDC00;\
if (val > 0x3FFU || hi > 0x3FFU)\
ERROR\
val += (hi<<10) + 0x10000;\
}\
}\
/**
* @def PUT_UTF8(val, tmp, PUT_BYTE)
* Convert a 32-bit Unicode character to its UTF-8 encoded form (up to 4 bytes long).
* @param val is an input-only argument and should be of type uint32_t. It holds
* a UCS-4 encoded Unicode character that is to be converted to UTF-8. If
* val is given as a function it is executed only once.
* @param tmp is a temporary variable and should be of type uint8_t. It
* represents an intermediate value during conversion that is to be
* output by PUT_BYTE.
* @param PUT_BYTE writes the converted UTF-8 bytes to any proper destination.
* It could be a function or a statement, and uses tmp as the input byte.
* For example, PUT_BYTE could be "*output++ = tmp;" PUT_BYTE will be
* executed up to 4 times for values in the valid UTF-8 range and up to
* 7 times in the general case, depending on the length of the converted
* Unicode character.
*/
#define PUT_UTF8(val, tmp, PUT_BYTE)\
{\
int bytes, shift;\
uint32_t in = val;\
if (in < 0x80) {\
tmp = in;\
PUT_BYTE\
} else {\
bytes = (av_log2(in) + 4) / 5;\
shift = (bytes - 1) * 6;\
tmp = (256 - (256 >> bytes)) | (in >> shift);\
PUT_BYTE\
while (shift >= 6) {\
shift -= 6;\
tmp = 0x80 | ((in >> shift) & 0x3f);\
PUT_BYTE\
}\
}\
}
/**
* @def PUT_UTF16(val, tmp, PUT_16BIT)
* Convert a 32-bit Unicode character to its UTF-16 encoded form (2 or 4 bytes).
* @param val is an input-only argument and should be of type uint32_t. It holds
* a UCS-4 encoded Unicode character that is to be converted to UTF-16. If
* val is given as a function it is executed only once.
* @param tmp is a temporary variable and should be of type uint16_t. It
* represents an intermediate value during conversion that is to be
* output by PUT_16BIT.
* @param PUT_16BIT writes the converted UTF-16 data to any proper destination
* in desired endianness. It could be a function or a statement, and uses tmp
* as the input byte. For example, PUT_BYTE could be "*output++ = tmp;"
* PUT_BYTE will be executed 1 or 2 times depending on input character.
*/
#define PUT_UTF16(val, tmp, PUT_16BIT)\
{\
uint32_t in = val;\
if (in < 0x10000) {\
tmp = in;\
PUT_16BIT\
} else {\
tmp = 0xD800 | ((in - 0x10000) >> 10);\
PUT_16BIT\
tmp = 0xDC00 | ((in - 0x10000) & 0x3FF);\
PUT_16BIT\
}\
}\
#include "mem.h"
#ifdef HAVE_AV_CONFIG_H
# include "internal.h"
#endif /* HAVE_AV_CONFIG_H */
#endif /* AVUTIL_COMMON_H */
/*
* The following definitions are outside the multiple inclusion guard
* to ensure they are immediately available in intmath.h.
*/
#ifndef av_log2
# define av_log2 av_log2_c
#endif
#ifndef av_log2_16bit
# define av_log2_16bit av_log2_16bit_c
#endif
#ifndef av_ceil_log2
# define av_ceil_log2 av_ceil_log2_c
#endif
#ifndef av_clip
# define av_clip av_clip_c
#endif
#ifndef av_clip_uint8
# define av_clip_uint8 av_clip_uint8_c
#endif
#ifndef av_clip_int8
# define av_clip_int8 av_clip_int8_c
#endif
#ifndef av_clip_uint16
# define av_clip_uint16 av_clip_uint16_c
#endif
#ifndef av_clip_int16
# define av_clip_int16 av_clip_int16_c
#endif
#ifndef av_clipl_int32
# define av_clipl_int32 av_clipl_int32_c
#endif
#ifndef av_clip_uintp2
# define av_clip_uintp2 av_clip_uintp2_c
#endif
#ifndef av_clipf
# define av_clipf av_clipf_c
#endif
#ifndef av_popcount
# define av_popcount av_popcount_c
#endif
#ifndef av_popcount64
# define av_popcount64 av_popcount64_c
#endif
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