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 common.h
  23  * common internal and external API header
  24  */
  25
  26 #ifndef AVUTIL_COMMON_H
  27 #define AVUTIL_COMMON_H
  28
  29 #include <inttypes.h>
  30
  31 #ifdef HAVE_AV_CONFIG_H
  32 /* only include the following when compiling package */
  33 #    include "config.h"
  34
  35 #    include <stdlib.h>
  36 #    include <stdio.h>
  37 #    include <string.h>
  38 #    include <ctype.h>
  39 #    include <limits.h>
  40 #    include <errno.h>
  41 #    include <math.h>
  42 #endif /* HAVE_AV_CONFIG_H */
  43
  44 #define AV_GCC_VERSION_AT_LEAST(x,y) (defined(__GNUC__) && (__GNUC__ > x || __GNUC__ == x && __GNUC_MINOR__ >= y))
  45
  46 #ifndef av_always_inline
  47 #if AV_GCC_VERSION_AT_LEAST(3,1)
  48 #    define av_always_inline __attribute__((always_inline)) inline
  49 #else
  50 #    define av_always_inline inline
  51 #endif
  52 #endif
  53
  54 #ifndef av_noinline
  55 #if AV_GCC_VERSION_AT_LEAST(3,1)
  56 #    define av_noinline __attribute__((noinline))
  57 #else
  58 #    define av_noinline
  59 #endif
  60 #endif
  61
  62 #ifndef av_pure
  63 #if AV_GCC_VERSION_AT_LEAST(3,1)
  64 #    define av_pure __attribute__((pure))
  65 #else
  66 #    define av_pure
  67 #endif
  68 #endif
  69
  70 #ifndef av_const
  71 #if AV_GCC_VERSION_AT_LEAST(2,6)
  72 #    define av_const __attribute__((const))
  73 #else
  74 #    define av_const
  75 #endif
  76 #endif
  77
  78 #ifndef av_cold
  79 #if (!defined(__ICC) || __ICC > 1100) && AV_GCC_VERSION_AT_LEAST(4,3)
  80 #    define av_cold __attribute__((cold))
  81 #else
  82 #    define av_cold
  83 #endif
  84 #endif
  85
  86 #ifdef HAVE_AV_CONFIG_H
  87 #    include "internal.h"
  88 #endif /* HAVE_AV_CONFIG_H */
  89
  90 #ifndef attribute_deprecated
  91 #if AV_GCC_VERSION_AT_LEAST(3,1)
  92 #    define attribute_deprecated __attribute__((deprecated))
  93 #else
  94 #    define attribute_deprecated
  95 #endif
  96 #endif
  97
  98 #ifndef av_unused
  99 #if defined(__GNUC__)
 100 #    define av_unused __attribute__((unused))
 101 #else
 102 #    define av_unused
 103 #endif
 104 #endif
 105
 106 #include "mem.h"
 107
 108 //rounded divison & shift
 109 #define RSHIFT(a,b) ((a) > 0 ? ((a) + ((1<<(b))>>1))>>(b) : ((a) + ((1<<(b))>>1)-1)>>(b))
 110 /* assume b>0 */
 111 #define ROUNDED_DIV(a,b) (((a)>0 ? (a) + ((b)>>1) : (a) - ((b)>>1))/(b))
 112 #define FFABS(a) ((a) >= 0 ? (a) : (-(a)))
 113 #define FFSIGN(a) ((a) > 0 ? 1 : -1)
 114
 115 #define FFMAX(a,b) ((a) > (b) ? (a) : (b))
 116 #define FFMAX3(a,b,c) FFMAX(FFMAX(a,b),c)
 117 #define FFMIN(a,b) ((a) > (b) ? (b) : (a))
 118 #define FFMIN3(a,b,c) FFMIN(FFMIN(a,b),c)
 119
 120 #define FFSWAP(type,a,b) do{type SWAP_tmp= b; b= a; a= SWAP_tmp;}while(0)
 121 #define FF_ARRAY_ELEMS(a) (sizeof(a) / sizeof((a)[0]))
 122
 123 /* misc math functions */
 124 extern const uint8_t ff_log2_tab[256];
 125
 126 static inline av_const int av_log2(unsigned int v)
 127 {
 128     int n = 0;
 129     if (v & 0xffff0000) {
 130         v >>= 16;
 131         n += 16;
 132     }
 133     if (v & 0xff00) {
 134         v >>= 8;
 135         n += 8;
 136     }
 137     n += ff_log2_tab[v];
 138
 139     return n;
 140 }
 141
 142 static inline av_const int av_log2_16bit(unsigned int v)
 143 {
 144     int n = 0;
 145     if (v & 0xff00) {
 146         v >>= 8;
 147         n += 8;
 148     }
 149     n += ff_log2_tab[v];
 150
 151     return n;
 152 }
 153
 154 /**
 155  * clip a signed integer value into the amin-amax range
 156  * @param a value to clip
 157  * @param amin minimum value of the clip range
 158  * @param amax maximum value of the clip range
 159  * @return clipped value
 160  */
 161 static inline av_const int av_clip(int a, int amin, int amax)
 162 {
 163     if      (a < amin) return amin;
 164     else if (a > amax) return amax;
 165     else               return a;
 166 }
 167
 168 /**
 169  * clip a signed integer value into the 0-255 range
 170  * @param a value to clip
 171  * @return clipped value
 172  */
 173 static inline av_const uint8_t av_clip_uint8(int a)
 174 {
 175     if (a&(~255)) return (-a)>>31;
 176     else          return a;
 177 }
 178
 179 /**
 180  * clip a signed integer value into the -32768,32767 range
 181  * @param a value to clip
 182  * @return clipped value
 183  */
 184 static inline av_const int16_t av_clip_int16(int a)
 185 {
 186     if ((a+32768) & ~65535) return (a>>31) ^ 32767;
 187     else                    return a;
 188 }
 189
 190 /**
 191  * clip a float value into the amin-amax range
 192  * @param a value to clip
 193  * @param amin minimum value of the clip range
 194  * @param amax maximum value of the clip range
 195  * @return clipped value
 196  */
 197 static inline av_const float av_clipf(float a, float amin, float amax)
 198 {
 199     if      (a < amin) return amin;
 200     else if (a > amax) return amax;
 201     else               return a;
 202 }
 203
 204 #define MKTAG(a,b,c,d) (a | (b << 8) | (c << 16) | (d << 24))
 205 #define MKBETAG(a,b,c,d) (d | (c << 8) | (b << 16) | (a << 24))
 206
 207 /*!
 208  * \def GET_UTF8(val, GET_BYTE, ERROR)
 209  * converts a UTF-8 character (up to 4 bytes long) to its 32-bit UCS-4 encoded form
 210  * \param val is the output and should be of type uint32_t. It holds the converted
 211  * UCS-4 character and should be a left value.
 212  * \param GET_BYTE gets UTF-8 encoded bytes from any proper source. It can be
 213  * a function or a statement whose return value or evaluated value is of type
 214  * uint8_t. It will be executed up to 4 times for values in the valid UTF-8 range,
 215  * and up to 7 times in the general case.
 216  * \param ERROR action that should be taken when an invalid UTF-8 byte is returned
 217  * from GET_BYTE. It should be a statement that jumps out of the macro,
 218  * like exit(), goto, return, break, or continue.
 219  */
 220 #define GET_UTF8(val, GET_BYTE, ERROR)\
 221     val= GET_BYTE;\
 222     {\
 223         int ones= 7 - av_log2(val ^ 255);\
 224         if(ones==1)\
 225             ERROR\
 226         val&= 127>>ones;\
 227         while(--ones > 0){\
 228             int tmp= GET_BYTE - 128;\
 229             if(tmp>>6)\
 230                 ERROR\
 231             val= (val<<6) + tmp;\
 232         }\
 233     }
 234
 235 /*!
 236  * \def PUT_UTF8(val, tmp, PUT_BYTE)
 237  * converts a 32-bit unicode character to its UTF-8 encoded form (up to 4 bytes long).
 238  * \param val is an input only argument and should be of type uint32_t. It holds
 239  * a ucs4 encoded unicode character that is to be converted to UTF-8. If
 240  * val is given as a function it's executed only once.
 241  * \param tmp is a temporary variable and should be of type uint8_t. It
 242  * represents an intermediate value during conversion that is to be
 243  * outputted by PUT_BYTE.
 244  * \param PUT_BYTE writes the converted UTF-8 bytes to any proper destination.
 245  * It could be a function or a statement, and uses tmp as the input byte.
 246  * For example, PUT_BYTE could be "*output++ = tmp;" PUT_BYTE will be
 247  * executed up to 4 times for values in the valid UTF-8 range and up to
 248  * 7 times in the general case, depending on the length of the converted
 249  * unicode character.
 250  */
 251 #define PUT_UTF8(val, tmp, PUT_BYTE)\
 252     {\
 253         int bytes, shift;\
 254         uint32_t in = val;\
 255         if (in < 0x80) {\
 256             tmp = in;\
 257             PUT_BYTE\
 258         } else {\
 259             bytes = (av_log2(in) + 4) / 5;\
 260             shift = (bytes - 1) * 6;\
 261             tmp = (256 - (256 >> bytes)) | (in >> shift);\
 262             PUT_BYTE\
 263             while (shift >= 6) {\
 264                 shift -= 6;\
 265                 tmp = 0x80 | ((in >> shift) & 0x3f);\
 266                 PUT_BYTE\
 267             }\
 268         }\
 269     }
 270
 271 #endif /* AVUTIL_COMMON_H */