ffmpeg/libavutil/common.h

298 lines
8.9 KiB
C

/*
* 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 libavutil/common.h
* 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"
//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 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];
extern const uint8_t av_reverse[256];
static 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 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
#ifndef av_log2
# define av_log2 av_log2_c
#endif
#ifndef av_log2_16bit
# define av_log2_16bit av_log2_16bit_c
#endif
/**
* Clips 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 inline av_const int av_clip(int a, int amin, int amax)
{
if (a < amin) return amin;
else if (a > amax) return amax;
else return a;
}
/**
* Clips a signed integer value into the 0-255 range.
* @param a value to clip
* @return clipped value
*/
static inline av_const uint8_t av_clip_uint8(int a)
{
if (a&(~255)) return (-a)>>31;
else return a;
}
/**
* Clips a signed integer value into the 0-65535 range.
* @param a value to clip
* @return clipped value
*/
static inline av_const uint16_t av_clip_uint16(int a)
{
if (a&(~65535)) return (-a)>>31;
else return a;
}
/**
* Clips a signed integer value into the -32768,32767 range.
* @param a value to clip
* @return clipped value
*/
static inline av_const int16_t av_clip_int16(int a)
{
if ((a+32768) & ~65535) return (a>>31) ^ 32767;
else return a;
}
/**
* Clips 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 inline av_const float av_clipf(float a, float amin, float amax)
{
if (a < amin) return amin;
else if (a > amax) return amax;
else return a;
}
/** Computes ceil(log2(x)).
* @param x value used to compute ceil(log2(x))
* @return computed ceiling of log2(x)
*/
static inline av_const int av_ceil_log2(int x)
{
return av_log2((x - 1) << 1);
}
#define MKTAG(a,b,c,d) (a | (b << 8) | (c << 16) | (d << 24))
#define MKBETAG(a,b,c,d) (d | (c << 8) | (b << 16) | (a << 24))
/*!
* \def GET_UTF8(val, GET_BYTE, ERROR)
* Converts a UTF-8 character (up to 4 bytes long) to its 32-bit UCS-4 encoded form
* \param val is the output and should be of type uint32_t. It holds the converted
* UCS-4 character and should be a left value.
* \param GET_BYTE gets UTF-8 encoded bytes from any proper source. It can be
* a function or a statement whose return value or evaluated value is of type
* uint8_t. It will be executed up to 4 times for values in the valid UTF-8 range,
* and up to 7 times in the general case.
* \param ERROR action that should be taken when an invalid UTF-8 byte is returned
* from GET_BYTE. It should be a statement that jumps out of the macro,
* like exit(), goto, return, break, or continue.
*/
#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;\
}\
}
/*!
* \def GET_UTF16(val, GET_16BIT, ERROR)
* Converts a UTF-16 character (2 or 4 bytes) to its 32-bit UCS-4 encoded form
* \param val is the output and should be of type uint32_t. It holds the converted
* UCS-4 character and should be a left value.
* \param GET_16BIT gets two bytes of UTF-16 encoded data converted to native endianness.
* It can be a function or a statement whose return value or evaluated value is of type
* uint16_t. It will be executed up to 2 times.
* \param ERROR action that should be taken when an invalid UTF-16 surrogate is
* returned from GET_BYTE. It should be a statement that jumps out of the macro,
* like exit(), goto, return, break, or continue.
*/
#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)
* Converts 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)
* Converts 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 */