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 */
132extern const uint8_t ff_log2_tab[256];
133
134static 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
150static 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 */
169static 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 */
181static 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 */
192static 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 */
205static 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 */
287