7c8c66b0c6be9cd1dc0c290f47f0422bb86ddf87
[libav.git] / 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 #ifndef attribute_deprecated
87 #if AV_GCC_VERSION_AT_LEAST(3,1)
88 # define attribute_deprecated __attribute__((deprecated))
89 #else
90 # define attribute_deprecated
91 #endif
92 #endif
93
94 #ifndef av_unused
95 #if defined(__GNUC__)
96 # define av_unused __attribute__((unused))
97 #else
98 # define av_unused
99 #endif
100 #endif
101
102 #include "mem.h"
103
104 //rounded divison & shift
105 #define RSHIFT(a,b) ((a) > 0 ? ((a) + ((1<<(b))>>1))>>(b) : ((a) + ((1<<(b))>>1)-1)>>(b))
106 /* assume b>0 */
107 #define ROUNDED_DIV(a,b) (((a)>0 ? (a) + ((b)>>1) : (a) - ((b)>>1))/(b))
108 #define FFABS(a) ((a) >= 0 ? (a) : (-(a)))
109 #define FFSIGN(a) ((a) > 0 ? 1 : -1)
110
111 #define FFMAX(a,b) ((a) > (b) ? (a) : (b))
112 #define FFMAX3(a,b,c) FFMAX(FFMAX(a,b),c)
113 #define FFMIN(a,b) ((a) > (b) ? (b) : (a))
114 #define FFMIN3(a,b,c) FFMIN(FFMIN(a,b),c)
115
116 #define FFSWAP(type,a,b) do{type SWAP_tmp= b; b= a; a= SWAP_tmp;}while(0)
117 #define FF_ARRAY_ELEMS(a) (sizeof(a) / sizeof((a)[0]))
118
119 /* misc math functions */
120 extern const uint8_t ff_log2_tab[256];
121
122 static inline av_const int av_log2(unsigned int v)
123 {
124 int n = 0;
125 if (v & 0xffff0000) {
126 v >>= 16;
127 n += 16;
128 }
129 if (v & 0xff00) {
130 v >>= 8;
131 n += 8;
132 }
133 n += ff_log2_tab[v];
134
135 return n;
136 }
137
138 static inline av_const int av_log2_16bit(unsigned int v)
139 {
140 int n = 0;
141 if (v & 0xff00) {
142 v >>= 8;
143 n += 8;
144 }
145 n += ff_log2_tab[v];
146
147 return n;
148 }
149
150 /**
151 * clip a signed integer value into the amin-amax range
152 * @param a value to clip
153 * @param amin minimum value of the clip range
154 * @param amax maximum value of the clip range
155 * @return clipped value
156 */
157 static inline av_const int av_clip(int a, int amin, int amax)
158 {
159 if (a < amin) return amin;
160 else if (a > amax) return amax;
161 else return a;
162 }
163
164 /**
165 * clip a signed integer value into the 0-255 range
166 * @param a value to clip
167 * @return clipped value
168 */
169 static inline av_const uint8_t av_clip_uint8(int a)
170 {
171 if (a&(~255)) return (-a)>>31;
172 else return a;
173 }
174
175 /**
176 * clip a signed integer value into the -32768,32767 range
177 * @param a value to clip
178 * @return clipped value
179 */
180 static inline av_const int16_t av_clip_int16(int a)
181 {
182 if ((a+32768) & ~65535) return (a>>31) ^ 32767;
183 else return a;
184 }
185
186 /**
187 * clip a float value into the amin-amax range
188 * @param a value to clip
189 * @param amin minimum value of the clip range
190 * @param amax maximum value of the clip range
191 * @return clipped value
192 */
193 static inline av_const float av_clipf(float a, float amin, float amax)
194 {
195 if (a < amin) return amin;
196 else if (a > amax) return amax;
197 else return a;
198 }
199
200 #define MKTAG(a,b,c,d) (a | (b << 8) | (c << 16) | (d << 24))
201 #define MKBETAG(a,b,c,d) (d | (c << 8) | (b << 16) | (a << 24))
202
203 /*!
204 * \def GET_UTF8(val, GET_BYTE, ERROR)
205 * converts a UTF-8 character (up to 4 bytes long) to its 32-bit UCS-4 encoded form
206 * \param val is the output and should be of type uint32_t. It holds the converted
207 * UCS-4 character and should be a left value.
208 * \param GET_BYTE gets UTF-8 encoded bytes from any proper source. It can be
209 * a function or a statement whose return value or evaluated value is of type
210 * uint8_t. It will be executed up to 4 times for values in the valid UTF-8 range,
211 * and up to 7 times in the general case.
212 * \param ERROR action that should be taken when an invalid UTF-8 byte is returned
213 * from GET_BYTE. It should be a statement that jumps out of the macro,
214 * like exit(), goto, return, break, or continue.
215 */
216 #define GET_UTF8(val, GET_BYTE, ERROR)\
217 val= GET_BYTE;\
218 {\
219 int ones= 7 - av_log2(val ^ 255);\
220 if(ones==1)\
221 ERROR\
222 val&= 127>>ones;\
223 while(--ones > 0){\
224 int tmp= GET_BYTE - 128;\
225 if(tmp>>6)\
226 ERROR\
227 val= (val<<6) + tmp;\
228 }\
229 }
230
231 /*!
232 * \def PUT_UTF8(val, tmp, PUT_BYTE)
233 * converts a 32-bit unicode character to its UTF-8 encoded form (up to 4 bytes long).
234 * \param val is an input only argument and should be of type uint32_t. It holds
235 * a ucs4 encoded unicode character that is to be converted to UTF-8. If
236 * val is given as a function it's executed only once.
237 * \param tmp is a temporary variable and should be of type uint8_t. It
238 * represents an intermediate value during conversion that is to be
239 * outputted by PUT_BYTE.
240 * \param PUT_BYTE writes the converted UTF-8 bytes to any proper destination.
241 * It could be a function or a statement, and uses tmp as the input byte.
242 * For example, PUT_BYTE could be "*output++ = tmp;" PUT_BYTE will be
243 * executed up to 4 times for values in the valid UTF-8 range and up to
244 * 7 times in the general case, depending on the length of the converted
245 * unicode character.
246 */
247 #define PUT_UTF8(val, tmp, PUT_BYTE)\
248 {\
249 int bytes, shift;\
250 uint32_t in = val;\
251 if (in < 0x80) {\
252 tmp = in;\
253 PUT_BYTE\
254 } else {\
255 bytes = (av_log2(in) + 4) / 5;\
256 shift = (bytes - 1) * 6;\
257 tmp = (256 - (256 >> bytes)) | (in >> shift);\
258 PUT_BYTE\
259 while (shift >= 6) {\
260 shift -= 6;\
261 tmp = 0x80 | ((in >> shift) & 0x3f);\
262 PUT_BYTE\
263 }\
264 }\
265 }
266
267 #ifdef HAVE_AV_CONFIG_H
268 # include "internal.h"
269 #endif /* HAVE_AV_CONFIG_H */
270
271 #endif /* AVUTIL_COMMON_H */