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
23  * common internal and external API header
24  */
25 
26 #ifndef AVUTIL_COMMON_H
27 #define AVUTIL_COMMON_H
28 
29 #if defined(__cplusplus) && !defined(__STDC_CONSTANT_MACROS) && !defined(UINT64_C)
30 #error missing -D__STDC_CONSTANT_MACROS / #define __STDC_CONSTANT_MACROS
31 #endif
32 
33 #include <errno.h>
34 #include <inttypes.h>
35 #include <limits.h>
36 #include <math.h>
37 #include <stdint.h>
38 #include <stdio.h>
39 #include <stdlib.h>
40 #include <string.h>
41 
42 #include "attributes.h"
43 #include "macros.h"
44 #include "version.h"
45 #include "libavutil/avconfig.h"
46 
47 #if AV_HAVE_BIGENDIAN
48 #   define AV_NE(be, le) (be)
49 #else
50 #   define AV_NE(be, le) (le)
51 #endif
52 
53 //rounded division & shift
54 #define RSHIFT(a,b) ((a) > 0 ? ((a) + ((1<<(b))>>1))>>(b) : ((a) + ((1<<(b))>>1)-1)>>(b))
55 /* assume b>0 */
56 #define ROUNDED_DIV(a,b) (((a)>=0 ? (a) + ((b)>>1) : (a) - ((b)>>1))/(b))
57 /* Fast a/(1<<b) rounded toward +inf. Assume a>=0 and b>=0 */
58 #define AV_CEIL_RSHIFT(a,b) (!av_builtin_constant_p(b) ? -((-(a)) >> (b)) \
59                                                        : ((a) + (1<<(b)) - 1) >> (b))
60 /* Backwards compat. */
61 #define FF_CEIL_RSHIFT AV_CEIL_RSHIFT
62 
63 #define FFUDIV(a,b) (((a)>0 ?(a):(a)-(b)+1) / (b))
64 #define FFUMOD(a,b) ((a)-(b)*FFUDIV(a,b))
65 
66 /**
67  * Absolute value, Note, INT_MIN / INT64_MIN result in undefined behavior as they
68  * are not representable as absolute values of their type. This is the same
69  * as with *abs()
70  * @see FFNABS()
71  */
72 #define FFABS(a) ((a) >= 0 ? (a) : (-(a)))
73 #define FFSIGN(a) ((a) > 0 ? 1 : -1)
74 
75 /**
76  * Negative Absolute value.
77  * this works for all integers of all types.
78  * As with many macros, this evaluates its argument twice, it thus must not have
79  * a sideeffect, that is FFNABS(x++) has undefined behavior.
80  */
81 #define FFNABS(a) ((a) <= 0 ? (a) : (-(a)))
82 
83 /**
84  * Unsigned Absolute value.
85  * This takes the absolute value of a signed int and returns it as a unsigned.
86  * This also works with INT_MIN which would otherwise not be representable
87  * As with many macros, this evaluates its argument twice.
88  */
89 #define FFABSU(a) ((a) <= 0 ? -(unsigned)(a) : (unsigned)(a))
90 #define FFABS64U(a) ((a) <= 0 ? -(uint64_t)(a) : (uint64_t)(a))
91 
92 /**
93  * Comparator.
94  * For two numerical expressions x and y, gives 1 if x > y, -1 if x < y, and 0
95  * if x == y. This is useful for instance in a qsort comparator callback.
96  * Furthermore, compilers are able to optimize this to branchless code, and
97  * there is no risk of overflow with signed types.
98  * As with many macros, this evaluates its argument multiple times, it thus
99  * must not have a side-effect.
100  */
101 #define FFDIFFSIGN(x,y) (((x)>(y)) - ((x)<(y)))
102 
103 #define FFMAX(a,b) ((a) > (b) ? (a) : (b))
104 #define FFMAX3(a,b,c) FFMAX(FFMAX(a,b),c)
105 #define FFMIN(a,b) ((a) > (b) ? (b) : (a))
106 #define FFMIN3(a,b,c) FFMIN(FFMIN(a,b),c)
107 
108 #define FFSWAP(type,a,b) do{type SWAP_tmp= b; b= a; a= SWAP_tmp;}while(0)
109 #define FF_ARRAY_ELEMS(a) (sizeof(a) / sizeof((a)[0]))
110 
111 /* misc math functions */
112 
113 #ifdef HAVE_AV_CONFIG_H
114 #   include "config.h"
115 #   include "intmath.h"
116 #endif
117 
118 #ifndef av_ceil_log2
119 #   define av_ceil_log2     av_ceil_log2_c
120 #endif
121 #ifndef av_clip
122 #   define av_clip          av_clip_c
123 #endif
124 #ifndef av_clip64
125 #   define av_clip64        av_clip64_c
126 #endif
127 #ifndef av_clip_uint8
128 #   define av_clip_uint8    av_clip_uint8_c
129 #endif
130 #ifndef av_clip_int8
131 #   define av_clip_int8     av_clip_int8_c
132 #endif
133 #ifndef av_clip_uint16
134 #   define av_clip_uint16   av_clip_uint16_c
135 #endif
136 #ifndef av_clip_int16
137 #   define av_clip_int16    av_clip_int16_c
138 #endif
139 #ifndef av_clipl_int32
140 #   define av_clipl_int32   av_clipl_int32_c
141 #endif
142 #ifndef av_clip_intp2
143 #   define av_clip_intp2    av_clip_intp2_c
144 #endif
145 #ifndef av_clip_uintp2
146 #   define av_clip_uintp2   av_clip_uintp2_c
147 #endif
148 #ifndef av_mod_uintp2
149 #   define av_mod_uintp2    av_mod_uintp2_c
150 #endif
151 #ifndef av_sat_add32
152 #   define av_sat_add32     av_sat_add32_c
153 #endif
154 #ifndef av_sat_dadd32
155 #   define av_sat_dadd32    av_sat_dadd32_c
156 #endif
157 #ifndef av_sat_sub32
158 #   define av_sat_sub32     av_sat_sub32_c
159 #endif
160 #ifndef av_sat_dsub32
161 #   define av_sat_dsub32    av_sat_dsub32_c
162 #endif
163 #ifndef av_sat_add64
164 #   define av_sat_add64     av_sat_add64_c
165 #endif
166 #ifndef av_sat_sub64
167 #   define av_sat_sub64     av_sat_sub64_c
168 #endif
169 #ifndef av_clipf
170 #   define av_clipf         av_clipf_c
171 #endif
172 #ifndef av_clipd
173 #   define av_clipd         av_clipd_c
174 #endif
175 #ifndef av_popcount
176 #   define av_popcount      av_popcount_c
177 #endif
178 #ifndef av_popcount64
179 #   define av_popcount64    av_popcount64_c
180 #endif
181 #ifndef av_parity
182 #   define av_parity        av_parity_c
183 #endif
184 
185 #ifndef av_log2
186 av_const int av_log2(unsigned v);
187 #endif
188 
189 #ifndef av_log2_16bit
190 av_const int av_log2_16bit(unsigned v);
191 #endif
192 
193 /**
194  * Clip a signed integer value into the amin-amax range.
195  * @param a value to clip
196  * @param amin minimum value of the clip range
197  * @param amax maximum value of the clip range
198  * @return clipped value
199  */
av_clip_c(int a,int amin,int amax)200 static av_always_inline av_const int av_clip_c(int a, int amin, int amax)
201 {
202 #if defined(HAVE_AV_CONFIG_H) && defined(ASSERT_LEVEL) && ASSERT_LEVEL >= 2
203     if (amin > amax) abort();
204 #endif
205     if      (a < amin) return amin;
206     else if (a > amax) return amax;
207     else               return a;
208 }
209 
210 /**
211  * Clip a signed 64bit integer value into the amin-amax range.
212  * @param a value to clip
213  * @param amin minimum value of the clip range
214  * @param amax maximum value of the clip range
215  * @return clipped value
216  */
av_clip64_c(int64_t a,int64_t amin,int64_t amax)217 static av_always_inline av_const int64_t av_clip64_c(int64_t a, int64_t amin, int64_t amax)
218 {
219 #if defined(HAVE_AV_CONFIG_H) && defined(ASSERT_LEVEL) && ASSERT_LEVEL >= 2
220     if (amin > amax) abort();
221 #endif
222     if      (a < amin) return amin;
223     else if (a > amax) return amax;
224     else               return a;
225 }
226 
227 /**
228  * Clip a signed integer value into the 0-255 range.
229  * @param a value to clip
230  * @return clipped value
231  */
av_clip_uint8_c(int a)232 static av_always_inline av_const uint8_t av_clip_uint8_c(int a)
233 {
234     if (a&(~0xFF)) return (~a)>>31;
235     else           return a;
236 }
237 
238 /**
239  * Clip a signed integer value into the -128,127 range.
240  * @param a value to clip
241  * @return clipped value
242  */
av_clip_int8_c(int a)243 static av_always_inline av_const int8_t av_clip_int8_c(int a)
244 {
245     if ((a+0x80U) & ~0xFF) return (a>>31) ^ 0x7F;
246     else                  return a;
247 }
248 
249 /**
250  * Clip a signed integer value into the 0-65535 range.
251  * @param a value to clip
252  * @return clipped value
253  */
av_clip_uint16_c(int a)254 static av_always_inline av_const uint16_t av_clip_uint16_c(int a)
255 {
256     if (a&(~0xFFFF)) return (~a)>>31;
257     else             return a;
258 }
259 
260 /**
261  * Clip a signed integer value into the -32768,32767 range.
262  * @param a value to clip
263  * @return clipped value
264  */
av_clip_int16_c(int a)265 static av_always_inline av_const int16_t av_clip_int16_c(int a)
266 {
267     if ((a+0x8000U) & ~0xFFFF) return (a>>31) ^ 0x7FFF;
268     else                      return a;
269 }
270 
271 /**
272  * Clip a signed 64-bit integer value into the -2147483648,2147483647 range.
273  * @param a value to clip
274  * @return clipped value
275  */
av_clipl_int32_c(int64_t a)276 static av_always_inline av_const int32_t av_clipl_int32_c(int64_t a)
277 {
278     if ((a+0x80000000u) & ~UINT64_C(0xFFFFFFFF)) return (int32_t)((a>>63) ^ 0x7FFFFFFF);
279     else                                         return (int32_t)a;
280 }
281 
282 /**
283  * Clip a signed integer into the -(2^p),(2^p-1) range.
284  * @param  a value to clip
285  * @param  p bit position to clip at
286  * @return clipped value
287  */
av_clip_intp2_c(int a,int p)288 static av_always_inline av_const int av_clip_intp2_c(int a, int p)
289 {
290     if (((unsigned)a + (1 << p)) & ~((2 << p) - 1))
291         return (a >> 31) ^ ((1 << p) - 1);
292     else
293         return a;
294 }
295 
296 /**
297  * Clip a signed integer to an unsigned power of two range.
298  * @param  a value to clip
299  * @param  p bit position to clip at
300  * @return clipped value
301  */
av_clip_uintp2_c(int a,int p)302 static av_always_inline av_const unsigned av_clip_uintp2_c(int a, int p)
303 {
304     if (a & ~((1<<p) - 1)) return (~a) >> 31 & ((1<<p) - 1);
305     else                   return  a;
306 }
307 
308 /**
309  * Clear high bits from an unsigned integer starting with specific bit position
310  * @param  a value to clip
311  * @param  p bit position to clip at
312  * @return clipped value
313  */
av_mod_uintp2_c(unsigned a,unsigned p)314 static av_always_inline av_const unsigned av_mod_uintp2_c(unsigned a, unsigned p)
315 {
316     return a & ((1U << p) - 1);
317 }
318 
319 /**
320  * Add two signed 32-bit values with saturation.
321  *
322  * @param  a one value
323  * @param  b another value
324  * @return sum with signed saturation
325  */
av_sat_add32_c(int a,int b)326 static av_always_inline int av_sat_add32_c(int a, int b)
327 {
328     return av_clipl_int32((int64_t)a + b);
329 }
330 
331 /**
332  * Add a doubled value to another value with saturation at both stages.
333  *
334  * @param  a first value
335  * @param  b value doubled and added to a
336  * @return sum sat(a + sat(2*b)) with signed saturation
337  */
av_sat_dadd32_c(int a,int b)338 static av_always_inline int av_sat_dadd32_c(int a, int b)
339 {
340     return av_sat_add32(a, av_sat_add32(b, b));
341 }
342 
343 /**
344  * Subtract two signed 32-bit values with saturation.
345  *
346  * @param  a one value
347  * @param  b another value
348  * @return difference with signed saturation
349  */
av_sat_sub32_c(int a,int b)350 static av_always_inline int av_sat_sub32_c(int a, int b)
351 {
352     return av_clipl_int32((int64_t)a - b);
353 }
354 
355 /**
356  * Subtract a doubled value from another value with saturation at both stages.
357  *
358  * @param  a first value
359  * @param  b value doubled and subtracted from a
360  * @return difference sat(a - sat(2*b)) with signed saturation
361  */
av_sat_dsub32_c(int a,int b)362 static av_always_inline int av_sat_dsub32_c(int a, int b)
363 {
364     return av_sat_sub32(a, av_sat_add32(b, b));
365 }
366 
367 /**
368  * Add two signed 64-bit values with saturation.
369  *
370  * @param  a one value
371  * @param  b another value
372  * @return sum with signed saturation
373  */
av_sat_add64_c(int64_t a,int64_t b)374 static av_always_inline int64_t av_sat_add64_c(int64_t a, int64_t b) {
375 #if (!defined(__INTEL_COMPILER) && AV_GCC_VERSION_AT_LEAST(5,1)) || AV_HAS_BUILTIN(__builtin_add_overflow)
376     int64_t tmp;
377     return !__builtin_add_overflow(a, b, &tmp) ? tmp : (tmp < 0 ? INT64_MAX : INT64_MIN);
378 #else
379     int64_t s = a+(uint64_t)b;
380     if ((int64_t)(a^b | ~s^b) >= 0)
381         return INT64_MAX ^ (b >> 63);
382     return s;
383 #endif
384 }
385 
386 /**
387  * Subtract two signed 64-bit values with saturation.
388  *
389  * @param  a one value
390  * @param  b another value
391  * @return difference with signed saturation
392  */
av_sat_sub64_c(int64_t a,int64_t b)393 static av_always_inline int64_t av_sat_sub64_c(int64_t a, int64_t b) {
394 #if (!defined(__INTEL_COMPILER) && AV_GCC_VERSION_AT_LEAST(5,1)) || AV_HAS_BUILTIN(__builtin_sub_overflow)
395     int64_t tmp;
396     return !__builtin_sub_overflow(a, b, &tmp) ? tmp : (tmp < 0 ? INT64_MAX : INT64_MIN);
397 #else
398     if (b <= 0 && a >= INT64_MAX + b)
399         return INT64_MAX;
400     if (b >= 0 && a <= INT64_MIN + b)
401         return INT64_MIN;
402     return a - b;
403 #endif
404 }
405 
406 /**
407  * Clip a float value into the amin-amax range.
408  * @param a value to clip
409  * @param amin minimum value of the clip range
410  * @param amax maximum value of the clip range
411  * @return clipped value
412  */
av_clipf_c(float a,float amin,float amax)413 static av_always_inline av_const float av_clipf_c(float a, float amin, float amax)
414 {
415 #if defined(HAVE_AV_CONFIG_H) && defined(ASSERT_LEVEL) && ASSERT_LEVEL >= 2
416     if (amin > amax) abort();
417 #endif
418     if      (a < amin) return amin;
419     else if (a > amax) return amax;
420     else               return a;
421 }
422 
423 /**
424  * Clip a double value into the amin-amax range.
425  * @param a value to clip
426  * @param amin minimum value of the clip range
427  * @param amax maximum value of the clip range
428  * @return clipped value
429  */
av_clipd_c(double a,double amin,double amax)430 static av_always_inline av_const double av_clipd_c(double a, double amin, double amax)
431 {
432 #if defined(HAVE_AV_CONFIG_H) && defined(ASSERT_LEVEL) && ASSERT_LEVEL >= 2
433     if (amin > amax) abort();
434 #endif
435     if      (a < amin) return amin;
436     else if (a > amax) return amax;
437     else               return a;
438 }
439 
440 /** Compute ceil(log2(x)).
441  * @param x value used to compute ceil(log2(x))
442  * @return computed ceiling of log2(x)
443  */
av_ceil_log2_c(int x)444 static av_always_inline av_const int av_ceil_log2_c(int x)
445 {
446     return av_log2((x - 1U) << 1);
447 }
448 
449 /**
450  * Count number of bits set to one in x
451  * @param x value to count bits of
452  * @return the number of bits set to one in x
453  */
av_popcount_c(uint32_t x)454 static av_always_inline av_const int av_popcount_c(uint32_t x)
455 {
456     x -= (x >> 1) & 0x55555555;
457     x = (x & 0x33333333) + ((x >> 2) & 0x33333333);
458     x = (x + (x >> 4)) & 0x0F0F0F0F;
459     x += x >> 8;
460     return (x + (x >> 16)) & 0x3F;
461 }
462 
463 /**
464  * Count number of bits set to one in x
465  * @param x value to count bits of
466  * @return the number of bits set to one in x
467  */
av_popcount64_c(uint64_t x)468 static av_always_inline av_const int av_popcount64_c(uint64_t x)
469 {
470     return av_popcount((uint32_t)x) + av_popcount((uint32_t)(x >> 32));
471 }
472 
av_parity_c(uint32_t v)473 static av_always_inline av_const int av_parity_c(uint32_t v)
474 {
475     return av_popcount(v) & 1;
476 }
477 
478 #define MKTAG(a,b,c,d) ((a) | ((b) << 8) | ((c) << 16) | ((unsigned)(d) << 24))
479 #define MKBETAG(a,b,c,d) ((d) | ((c) << 8) | ((b) << 16) | ((unsigned)(a) << 24))
480 
481 /**
482  * Convert a UTF-8 character (up to 4 bytes) to its 32-bit UCS-4 encoded form.
483  *
484  * @param val      Output value, must be an lvalue of type uint32_t.
485  * @param GET_BYTE Expression reading one byte from the input.
486  *                 Evaluated up to 7 times (4 for the currently
487  *                 assigned Unicode range).  With a memory buffer
488  *                 input, this could be *ptr++, or if you want to make sure
489  *                 that *ptr stops at the end of a NULL terminated string then
490  *                 *ptr ? *ptr++ : 0
491  * @param ERROR    Expression to be evaluated on invalid input,
492  *                 typically a goto statement.
493  *
494  * @warning ERROR should not contain a loop control statement which
495  * could interact with the internal while loop, and should force an
496  * exit from the macro code (e.g. through a goto or a return) in order
497  * to prevent undefined results.
498  */
499 #define GET_UTF8(val, GET_BYTE, ERROR)\
500     val= (GET_BYTE);\
501     {\
502         uint32_t top = (val & 128) >> 1;\
503         if ((val & 0xc0) == 0x80 || val >= 0xFE)\
504             {ERROR}\
505         while (val & top) {\
506             unsigned int tmp = (GET_BYTE) - 128;\
507             if(tmp>>6)\
508                 {ERROR}\
509             val= (val<<6) + tmp;\
510             top <<= 5;\
511         }\
512         val &= (top << 1) - 1;\
513     }
514 
515 /**
516  * Convert a UTF-16 character (2 or 4 bytes) to its 32-bit UCS-4 encoded form.
517  *
518  * @param val       Output value, must be an lvalue of type uint32_t.
519  * @param GET_16BIT Expression returning two bytes of UTF-16 data converted
520  *                  to native byte order.  Evaluated one or two times.
521  * @param ERROR     Expression to be evaluated on invalid input,
522  *                  typically a goto statement.
523  */
524 #define GET_UTF16(val, GET_16BIT, ERROR)\
525     val = (GET_16BIT);\
526     {\
527         unsigned int hi = val - 0xD800;\
528         if (hi < 0x800) {\
529             val = (GET_16BIT) - 0xDC00;\
530             if (val > 0x3FFU || hi > 0x3FFU)\
531                 {ERROR}\
532             val += (hi<<10) + 0x10000;\
533         }\
534     }\
535 
536 /**
537  * @def PUT_UTF8(val, tmp, PUT_BYTE)
538  * Convert a 32-bit Unicode character to its UTF-8 encoded form (up to 4 bytes long).
539  * @param val is an input-only argument and should be of type uint32_t. It holds
540  * a UCS-4 encoded Unicode character that is to be converted to UTF-8. If
541  * val is given as a function it is executed only once.
542  * @param tmp is a temporary variable and should be of type uint8_t. It
543  * represents an intermediate value during conversion that is to be
544  * output by PUT_BYTE.
545  * @param PUT_BYTE writes the converted UTF-8 bytes to any proper destination.
546  * It could be a function or a statement, and uses tmp as the input byte.
547  * For example, PUT_BYTE could be "*output++ = tmp;" PUT_BYTE will be
548  * executed up to 4 times for values in the valid UTF-8 range and up to
549  * 7 times in the general case, depending on the length of the converted
550  * Unicode character.
551  */
552 #define PUT_UTF8(val, tmp, PUT_BYTE)\
553     {\
554         int bytes, shift;\
555         uint32_t in = val;\
556         if (in < 0x80) {\
557             tmp = in;\
558             PUT_BYTE\
559         } else {\
560             bytes = (av_log2(in) + 4) / 5;\
561             shift = (bytes - 1) * 6;\
562             tmp = (256 - (256 >> bytes)) | (in >> shift);\
563             PUT_BYTE\
564             while (shift >= 6) {\
565                 shift -= 6;\
566                 tmp = 0x80 | ((in >> shift) & 0x3f);\
567                 PUT_BYTE\
568             }\
569         }\
570     }
571 
572 /**
573  * @def PUT_UTF16(val, tmp, PUT_16BIT)
574  * Convert a 32-bit Unicode character to its UTF-16 encoded form (2 or 4 bytes).
575  * @param val is an input-only argument and should be of type uint32_t. It holds
576  * a UCS-4 encoded Unicode character that is to be converted to UTF-16. If
577  * val is given as a function it is executed only once.
578  * @param tmp is a temporary variable and should be of type uint16_t. It
579  * represents an intermediate value during conversion that is to be
580  * output by PUT_16BIT.
581  * @param PUT_16BIT writes the converted UTF-16 data to any proper destination
582  * in desired endianness. It could be a function or a statement, and uses tmp
583  * as the input byte.  For example, PUT_BYTE could be "*output++ = tmp;"
584  * PUT_BYTE will be executed 1 or 2 times depending on input character.
585  */
586 #define PUT_UTF16(val, tmp, PUT_16BIT)\
587     {\
588         uint32_t in = val;\
589         if (in < 0x10000) {\
590             tmp = in;\
591             PUT_16BIT\
592         } else {\
593             tmp = 0xD800 | ((in - 0x10000) >> 10);\
594             PUT_16BIT\
595             tmp = 0xDC00 | ((in - 0x10000) & 0x3FF);\
596             PUT_16BIT\
597         }\
598     }\
599 
600 
601 
602 #include "mem.h"
603 
604 #ifdef HAVE_AV_CONFIG_H
605 #    include "internal.h"
606 #endif /* HAVE_AV_CONFIG_H */
607 
608 #endif /* AVUTIL_COMMON_H */
609