libavutil/common.h

   1 /*
   2  * copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at>
   3  *
   4  * This file is part of FFmpeg.
   5  *
   6  * FFmpeg is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * FFmpeg is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with FFmpeg; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  19  */
  20
  21 /**
  22  * @file libavutil/common.h
  23  * common internal and external API header
  24  */
  25
  26 #ifndef AVUTIL_COMMON_H
  27 #define AVUTIL_COMMON_H
  28
  29 #include <ctype.h>
  30 #include <errno.h>
  31 #include <inttypes.h>
  32 #include <limits.h>
  33 #include <math.h>
  34 #include <stdio.h>
  35 #include <stdlib.h>
  36 #include <string.h>
  37
  38 #ifdef __GNUC__
  39 #    define AV_GCC_VERSION_AT_LEAST(x,y) (__GNUC__ > x || __GNUC__ == x && __GNUC_MINOR__ >= y)
  40 #else
  41 #    define AV_GCC_VERSION_AT_LEAST(x,y) 0
  42 #endif
  43
  44 #ifndef av_always_inline
  45 #if AV_GCC_VERSION_AT_LEAST(3,1)
  46 #    define av_always_inline __attribute__((always_inline)) inline
  47 #else
  48 #    define av_always_inline inline
  49 #endif
  50 #endif
  51
  52 #ifndef av_noinline
  53 #if AV_GCC_VERSION_AT_LEAST(3,1)
  54 #    define av_noinline __attribute__((noinline))
  55 #else
  56 #    define av_noinline
  57 #endif
  58 #endif
  59
  60 #ifndef av_pure
  61 #if AV_GCC_VERSION_AT_LEAST(3,1)
  62 #    define av_pure __attribute__((pure))
  63 #else
  64 #    define av_pure
  65 #endif
  66 #endif
  67
  68 #ifndef av_const
  69 #if AV_GCC_VERSION_AT_LEAST(2,6)
  70 #    define av_const __attribute__((const))
  71 #else
  72 #    define av_const
  73 #endif
  74 #endif
  75
  76 #ifndef av_cold
  77 #if (!defined(__ICC) || __ICC > 1100) && AV_GCC_VERSION_AT_LEAST(4,3)
  78 #    define av_cold __attribute__((cold))
  79 #else
  80 #    define av_cold
  81 #endif
  82 #endif
  83
  84 #ifndef av_flatten
  85 #if AV_GCC_VERSION_AT_LEAST(4,1)
  86 #    define av_flatten __attribute__((flatten))
  87 #else
  88 #    define av_flatten
  89 #endif
  90 #endif
  91
  92 #ifndef attribute_deprecated
  93 #if AV_GCC_VERSION_AT_LEAST(3,1)
  94 #    define attribute_deprecated __attribute__((deprecated))
  95 #else
  96 #    define attribute_deprecated
  97 #endif
  98 #endif
  99
 100 #ifndef av_unused
 101 #if defined(__GNUC__)
 102 #    define av_unused __attribute__((unused))
 103 #else
 104 #    define av_unused
 105 #endif
 106 #endif
 107
 108 #ifndef av_uninit
 109 #if defined(__GNUC__) && !defined(__ICC)
 110 #    define av_uninit(x) x=x
 111 #else
 112 #    define av_uninit(x) x
 113 #endif
 114 #endif
 115
 116 //rounded division & shift
 117 #define RSHIFT(a,b) ((a) > 0 ? ((a) + ((1<<(b))>>1))>>(b) : ((a) + ((1<<(b))>>1)-1)>>(b))
 118 /* assume b>0 */
 119 #define ROUNDED_DIV(a,b) (((a)>0 ? (a) + ((b)>>1) : (a) - ((b)>>1))/(b))
 120 #define FFABS(a) ((a) >= 0 ? (a) : (-(a)))
 121 #define FFSIGN(a) ((a) > 0 ? 1 : -1)
 122
 123 #define FFMAX(a,b) ((a) > (b) ? (a) : (b))
 124 #define FFMAX3(a,b,c) FFMAX(FFMAX(a,b),c)
 125 #define FFMIN(a,b) ((a) > (b) ? (b) : (a))
 126 #define FFMIN3(a,b,c) FFMIN(FFMIN(a,b),c)
 127
 128 #define FFSWAP(type,a,b) do{type SWAP_tmp= b; b= a; a= SWAP_tmp;}while(0)
 129 #define FF_ARRAY_ELEMS(a) (sizeof(a) / sizeof((a)[0]))
 130
 131 /* misc math functions */
 132 extern const uint8_t ff_log2_tab[256];
 133
 134 static inline av_const int av_log2(unsigned int v)
 135 {
 136     int n = 0;
 137     if (v & 0xffff0000) {
 138         v >>= 16;
 139         n += 16;
 140     }
 141     if (v & 0xff00) {
 142         v >>= 8;
 143         n += 8;
 144     }
 145     n += ff_log2_tab[v];
 146
 147     return n;
 148 }
 149
 150 static inline av_const int av_log2_16bit(unsigned int v)
 151 {
 152     int n = 0;
 153     if (v & 0xff00) {
 154         v >>= 8;
 155         n += 8;
 156     }
 157     n += ff_log2_tab[v];
 158
 159     return n;
 160 }
 161
 162 /**
 163  * Clips a signed integer value into the amin-amax range.
 164  * @param a value to clip
 165  * @param amin minimum value of the clip range
 166  * @param amax maximum value of the clip range
 167  * @return clipped value
 168  */
 169 static inline av_const int av_clip(int a, int amin, int amax)
 170 {
 171     if      (a < amin) return amin;
 172     else if (a > amax) return amax;
 173     else               return a;
 174 }
 175
 176 /**
 177  * Clips a signed integer value into the 0-255 range.
 178  * @param a value to clip
 179  * @return clipped value
 180  */
 181 static inline av_const uint8_t av_clip_uint8(int a)
 182 {
 183     if (a&(~255)) return (-a)>>31;
 184     else          return a;
 185 }
 186
 187 /**
 188  * Clips a signed integer value into the -32768,32767 range.
 189  * @param a value to clip
 190  * @return clipped value
 191  */
 192 static inline av_const int16_t av_clip_int16(int a)
 193 {
 194     if ((a+32768) & ~65535) return (a>>31) ^ 32767;
 195     else                    return a;
 196 }
 197
 198 /**
 199  * Clips a float value into the amin-amax range.
 200  * @param a value to clip
 201  * @param amin minimum value of the clip range
 202  * @param amax maximum value of the clip range
 203  * @return clipped value
 204  */
 205 static inline av_const float av_clipf(float a, float amin, float amax)
 206 {
 207     if      (a < amin) return amin;
 208     else if (a > amax) return amax;
 209     else               return a;
 210 }
 211
 212 #define MKTAG(a,b,c,d) (a | (b << 8) | (c << 16) | (d << 24))
 213 #define MKBETAG(a,b,c,d) (d | (c << 8) | (b << 16) | (a << 24))
 214
 215 /*!
 216  * \def GET_UTF8(val, GET_BYTE, ERROR)
 217  * Converts a UTF-8 character (up to 4 bytes long) to its 32-bit UCS-4 encoded form
 218  * \param val is the output and should be of type uint32_t. It holds the converted
 219  * UCS-4 character and should be a left value.
 220  * \param GET_BYTE gets UTF-8 encoded bytes from any proper source. It can be
 221  * a function or a statement whose return value or evaluated value is of type
 222  * uint8_t. It will be executed up to 4 times for values in the valid UTF-8 range,
 223  * and up to 7 times in the general case.
 224  * \param ERROR action that should be taken when an invalid UTF-8 byte is returned
 225  * from GET_BYTE. It should be a statement that jumps out of the macro,
 226  * like exit(), goto, return, break, or continue.
 227  */
 228 #define GET_UTF8(val, GET_BYTE, ERROR)\
 229     val= GET_BYTE;\
 230     {\
 231         int ones= 7 - av_log2(val ^ 255);\
 232         if(ones==1)\
 233             ERROR\
 234         val&= 127>>ones;\
 235         while(--ones > 0){\
 236             int tmp= GET_BYTE - 128;\
 237             if(tmp>>6)\
 238                 ERROR\
 239             val= (val<<6) + tmp;\
 240         }\
 241     }
 242
 243 /*!
 244  * \def PUT_UTF8(val, tmp, PUT_BYTE)
 245  * Converts a 32-bit Unicode character to its UTF-8 encoded form (up to 4 bytes long).
 246  * \param val is an input-only argument and should be of type uint32_t. It holds
 247  * a UCS-4 encoded Unicode character that is to be converted to UTF-8. If
 248  * val is given as a function it is executed only once.
 249  * \param tmp is a temporary variable and should be of type uint8_t. It
 250  * represents an intermediate value during conversion that is to be
 251  * output by PUT_BYTE.
 252  * \param PUT_BYTE writes the converted UTF-8 bytes to any proper destination.
 253  * It could be a function or a statement, and uses tmp as the input byte.
 254  * For example, PUT_BYTE could be "*output++ = tmp;" PUT_BYTE will be
 255  * executed up to 4 times for values in the valid UTF-8 range and up to
 256  * 7 times in the general case, depending on the length of the converted
 257  * Unicode character.
 258  */
 259 #define PUT_UTF8(val, tmp, PUT_BYTE)\
 260     {\
 261         int bytes, shift;\
 262         uint32_t in = val;\
 263         if (in < 0x80) {\
 264             tmp = in;\
 265             PUT_BYTE\
 266         } else {\
 267             bytes = (av_log2(in) + 4) / 5;\
 268             shift = (bytes - 1) * 6;\
 269             tmp = (256 - (256 >> bytes)) | (in >> shift);\
 270             PUT_BYTE\
 271             while (shift >= 6) {\
 272                 shift -= 6;\
 273                 tmp = 0x80 | ((in >> shift) & 0x3f);\
 274                 PUT_BYTE\
 275             }\
 276         }\
 277     }
 278
 279 #include "mem.h"
 280
 281 #ifdef HAVE_AV_CONFIG_H
 282 #    include "config.h"
 283 #    include "internal.h"
 284 #endif /* HAVE_AV_CONFIG_H */
 285
 286 #endif /* AVUTIL_COMMON_H */