1 /*
2 * libmad - MPEG audio decoder library
3 * Copyright (C) 2000-2004 Underbit Technologies, Inc.
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18 *
19 * $Id: timer.c,v 1.18 2004/01/23 09:41:33 rob Exp $
20 */
21
22 # ifdef HAVE_CONFIG_H
23 # include "config.h"
24 # endif
25
26 # include "global.h"
27
28 # include <stdio.h>
29
30 # ifdef HAVE_ASSERT_H
31 # include <assert.h>
32 # endif
33
34 # include "timer.h"
35
36 mad_timer_t const mad_timer_zero = { 0, 0 };
37
38 /*
39 * NAME: timer->compare()
40 * DESCRIPTION: indicate relative order of two timers
41 */
mad_timer_compare(mad_timer_t timer1,mad_timer_t timer2)42 int mad_timer_compare(mad_timer_t timer1, mad_timer_t timer2)
43 {
44 signed long diff;
45
46 diff = timer1.seconds - timer2.seconds;
47 if (diff < 0)
48 return -1;
49 else if (diff > 0)
50 return +1;
51
52 diff = timer1.fraction - timer2.fraction;
53 if (diff < 0)
54 return -1;
55 else if (diff > 0)
56 return +1;
57
58 return 0;
59 }
60
61 /*
62 * NAME: timer->negate()
63 * DESCRIPTION: invert the sign of a timer
64 */
mad_timer_negate(mad_timer_t * timer)65 void mad_timer_negate(mad_timer_t *timer)
66 {
67 timer->seconds = -timer->seconds;
68
69 if (timer->fraction) {
70 timer->seconds -= 1;
71 timer->fraction = MAD_TIMER_RESOLUTION - timer->fraction;
72 }
73 }
74
75 /*
76 * NAME: timer->abs()
77 * DESCRIPTION: return the absolute value of a timer
78 */
mad_timer_abs(mad_timer_t timer)79 mad_timer_t mad_timer_abs(mad_timer_t timer)
80 {
81 if (timer.seconds < 0)
82 mad_timer_negate(&timer);
83
84 return timer;
85 }
86
87 /*
88 * NAME: reduce_timer()
89 * DESCRIPTION: carry timer fraction into seconds
90 */
91 static
reduce_timer(mad_timer_t * timer)92 void reduce_timer(mad_timer_t *timer)
93 {
94 timer->seconds += timer->fraction / MAD_TIMER_RESOLUTION;
95 timer->fraction %= MAD_TIMER_RESOLUTION;
96 }
97
98 /*
99 * NAME: gcd()
100 * DESCRIPTION: compute greatest common denominator
101 */
102 static
gcd(unsigned long num1,unsigned long num2)103 unsigned long gcd(unsigned long num1, unsigned long num2)
104 {
105 unsigned long tmp;
106
107 while (num2) {
108 tmp = num2;
109 num2 = num1 % num2;
110 num1 = tmp;
111 }
112
113 return num1;
114 }
115
116 /*
117 * NAME: reduce_rational()
118 * DESCRIPTION: convert rational expression to lowest terms
119 */
120 static
reduce_rational(unsigned long * numer,unsigned long * denom)121 void reduce_rational(unsigned long *numer, unsigned long *denom)
122 {
123 unsigned long factor;
124
125 factor = gcd(*numer, *denom);
126
127 assert(factor != 0);
128
129 *numer /= factor;
130 *denom /= factor;
131 }
132
133 /*
134 * NAME: scale_rational()
135 * DESCRIPTION: solve numer/denom == ?/scale avoiding overflowing
136 */
137 static
scale_rational(unsigned long numer,unsigned long denom,unsigned long scale)138 unsigned long scale_rational(unsigned long numer, unsigned long denom,
139 unsigned long scale)
140 {
141 reduce_rational(&numer, &denom);
142 reduce_rational(&scale, &denom);
143
144 assert(denom != 0);
145
146 if (denom < scale)
147 return numer * (scale / denom) + numer * (scale % denom) / denom;
148 if (denom < numer)
149 return scale * (numer / denom) + scale * (numer % denom) / denom;
150
151 return numer * scale / denom;
152 }
153
154 /*
155 * NAME: timer->set()
156 * DESCRIPTION: set timer to specific (positive) value
157 */
mad_timer_set(mad_timer_t * timer,unsigned long seconds,unsigned long numer,unsigned long denom)158 void mad_timer_set(mad_timer_t *timer, unsigned long seconds,
159 unsigned long numer, unsigned long denom)
160 {
161 timer->seconds = seconds;
162 if (numer >= denom && denom > 0) {
163 timer->seconds += numer / denom;
164 numer %= denom;
165 }
166
167 switch (denom) {
168 case 0:
169 case 1:
170 timer->fraction = 0;
171 break;
172
173 case MAD_TIMER_RESOLUTION:
174 timer->fraction = numer;
175 break;
176
177 case 1000:
178 timer->fraction = numer * (MAD_TIMER_RESOLUTION / 1000);
179 break;
180
181 case 8000:
182 timer->fraction = numer * (MAD_TIMER_RESOLUTION / 8000);
183 break;
184
185 case 11025:
186 timer->fraction = numer * (MAD_TIMER_RESOLUTION / 11025);
187 break;
188
189 case 12000:
190 timer->fraction = numer * (MAD_TIMER_RESOLUTION / 12000);
191 break;
192
193 case 16000:
194 timer->fraction = numer * (MAD_TIMER_RESOLUTION / 16000);
195 break;
196
197 case 22050:
198 timer->fraction = numer * (MAD_TIMER_RESOLUTION / 22050);
199 break;
200
201 case 24000:
202 timer->fraction = numer * (MAD_TIMER_RESOLUTION / 24000);
203 break;
204
205 case 32000:
206 timer->fraction = numer * (MAD_TIMER_RESOLUTION / 32000);
207 break;
208
209 case 44100:
210 timer->fraction = numer * (MAD_TIMER_RESOLUTION / 44100);
211 break;
212
213 case 48000:
214 timer->fraction = numer * (MAD_TIMER_RESOLUTION / 48000);
215 break;
216
217 default:
218 timer->fraction = scale_rational(numer, denom, MAD_TIMER_RESOLUTION);
219 break;
220 }
221
222 if (timer->fraction >= MAD_TIMER_RESOLUTION)
223 reduce_timer(timer);
224 }
225
226 /*
227 * NAME: timer->add()
228 * DESCRIPTION: add one timer to another
229 */
mad_timer_add(mad_timer_t * timer,mad_timer_t incr)230 void mad_timer_add(mad_timer_t *timer, mad_timer_t incr)
231 {
232 timer->seconds += incr.seconds;
233 timer->fraction += incr.fraction;
234
235 if (timer->fraction >= MAD_TIMER_RESOLUTION)
236 reduce_timer(timer);
237 }
238
239 /*
240 * NAME: timer->multiply()
241 * DESCRIPTION: multiply a timer by a scalar value
242 */
mad_timer_multiply(mad_timer_t * timer,signed long scalar)243 void mad_timer_multiply(mad_timer_t *timer, signed long scalar)
244 {
245 mad_timer_t addend;
246 unsigned long factor;
247
248 factor = scalar;
249 if (scalar < 0) {
250 factor = -scalar;
251 mad_timer_negate(timer);
252 }
253
254 addend = *timer;
255 *timer = mad_timer_zero;
256
257 while (factor) {
258 if (factor & 1)
259 mad_timer_add(timer, addend);
260
261 mad_timer_add(&addend, addend);
262 factor >>= 1;
263 }
264 }
265
266 /*
267 * NAME: timer->count()
268 * DESCRIPTION: return timer value in selected units
269 */
mad_timer_count(mad_timer_t timer,enum mad_units units)270 signed long mad_timer_count(mad_timer_t timer, enum mad_units units)
271 {
272 switch (units) {
273 case MAD_UNITS_HOURS:
274 return timer.seconds / 60 / 60;
275
276 case MAD_UNITS_MINUTES:
277 return timer.seconds / 60;
278
279 case MAD_UNITS_SECONDS:
280 return timer.seconds;
281
282 case MAD_UNITS_DECISECONDS:
283 case MAD_UNITS_CENTISECONDS:
284 case MAD_UNITS_MILLISECONDS:
285
286 case MAD_UNITS_8000_HZ:
287 case MAD_UNITS_11025_HZ:
288 case MAD_UNITS_12000_HZ:
289 case MAD_UNITS_16000_HZ:
290 case MAD_UNITS_22050_HZ:
291 case MAD_UNITS_24000_HZ:
292 case MAD_UNITS_32000_HZ:
293 case MAD_UNITS_44100_HZ:
294 case MAD_UNITS_48000_HZ:
295
296 case MAD_UNITS_24_FPS:
297 case MAD_UNITS_25_FPS:
298 case MAD_UNITS_30_FPS:
299 case MAD_UNITS_48_FPS:
300 case MAD_UNITS_50_FPS:
301 case MAD_UNITS_60_FPS:
302 case MAD_UNITS_75_FPS:
303 return timer.seconds * (signed long) units +
304 (signed long) scale_rational(timer.fraction, MAD_TIMER_RESOLUTION,
305 units);
306
307 case MAD_UNITS_23_976_FPS:
308 case MAD_UNITS_24_975_FPS:
309 case MAD_UNITS_29_97_FPS:
310 case MAD_UNITS_47_952_FPS:
311 case MAD_UNITS_49_95_FPS:
312 case MAD_UNITS_59_94_FPS:
313 return (mad_timer_count(timer, -units) + 1) * 1000 / 1001;
314 }
315
316 /* unsupported units */
317 return 0;
318 }
319
320 /*
321 * NAME: timer->fraction()
322 * DESCRIPTION: return fractional part of timer in arbitrary terms
323 */
mad_timer_fraction(mad_timer_t timer,unsigned long denom)324 unsigned long mad_timer_fraction(mad_timer_t timer, unsigned long denom)
325 {
326 timer = mad_timer_abs(timer);
327
328 switch (denom) {
329 case 0:
330 return timer.fraction ?
331 MAD_TIMER_RESOLUTION / timer.fraction : MAD_TIMER_RESOLUTION + 1;
332
333 case MAD_TIMER_RESOLUTION:
334 return timer.fraction;
335
336 default:
337 return scale_rational(timer.fraction, MAD_TIMER_RESOLUTION, denom);
338 }
339 }
340
341 /*
342 * NAME: timer->string()
343 * DESCRIPTION: write a string representation of a timer using a template
344 */
mad_timer_string(mad_timer_t timer,char * dest,char const * format,enum mad_units units,enum mad_units fracunits,unsigned long subparts)345 void mad_timer_string(mad_timer_t timer,
346 char *dest, char const *format, enum mad_units units,
347 enum mad_units fracunits, unsigned long subparts)
348 {
349 unsigned long hours, minutes, seconds, sub;
350 unsigned int frac;
351
352 timer = mad_timer_abs(timer);
353
354 seconds = timer.seconds;
355 frac = sub = 0;
356
357 switch (fracunits) {
358 case MAD_UNITS_HOURS:
359 case MAD_UNITS_MINUTES:
360 case MAD_UNITS_SECONDS:
361 break;
362
363 case MAD_UNITS_DECISECONDS:
364 case MAD_UNITS_CENTISECONDS:
365 case MAD_UNITS_MILLISECONDS:
366
367 case MAD_UNITS_8000_HZ:
368 case MAD_UNITS_11025_HZ:
369 case MAD_UNITS_12000_HZ:
370 case MAD_UNITS_16000_HZ:
371 case MAD_UNITS_22050_HZ:
372 case MAD_UNITS_24000_HZ:
373 case MAD_UNITS_32000_HZ:
374 case MAD_UNITS_44100_HZ:
375 case MAD_UNITS_48000_HZ:
376
377 case MAD_UNITS_24_FPS:
378 case MAD_UNITS_25_FPS:
379 case MAD_UNITS_30_FPS:
380 case MAD_UNITS_48_FPS:
381 case MAD_UNITS_50_FPS:
382 case MAD_UNITS_60_FPS:
383 case MAD_UNITS_75_FPS:
384 {
385 unsigned long denom;
386
387 denom = MAD_TIMER_RESOLUTION / fracunits;
388
389 frac = timer.fraction / denom;
390 sub = scale_rational(timer.fraction % denom, denom, subparts);
391 }
392 break;
393
394 case MAD_UNITS_23_976_FPS:
395 case MAD_UNITS_24_975_FPS:
396 case MAD_UNITS_29_97_FPS:
397 case MAD_UNITS_47_952_FPS:
398 case MAD_UNITS_49_95_FPS:
399 case MAD_UNITS_59_94_FPS:
400 /* drop-frame encoding */
401 /* N.B. this is only well-defined for MAD_UNITS_29_97_FPS */
402 {
403 unsigned long frame, cycle, d, m;
404
405 frame = mad_timer_count(timer, fracunits);
406
407 cycle = -fracunits * 60 * 10 - (10 - 1) * 2;
408
409 d = frame / cycle;
410 m = frame % cycle;
411 frame += (10 - 1) * 2 * d;
412 if (m > 2)
413 frame += 2 * ((m - 2) / (cycle / 10));
414
415 frac = frame % -fracunits;
416 seconds = frame / -fracunits;
417 }
418 break;
419 }
420
421 switch (units) {
422 case MAD_UNITS_HOURS:
423 minutes = seconds / 60;
424 hours = minutes / 60;
425
426 sprintf(dest, format,
427 hours,
428 (unsigned int) (minutes % 60),
429 (unsigned int) (seconds % 60),
430 frac, sub);
431 break;
432
433 case MAD_UNITS_MINUTES:
434 minutes = seconds / 60;
435
436 sprintf(dest, format,
437 minutes,
438 (unsigned int) (seconds % 60),
439 frac, sub);
440 break;
441
442 case MAD_UNITS_SECONDS:
443 sprintf(dest, format,
444 seconds,
445 frac, sub);
446 break;
447
448 case MAD_UNITS_23_976_FPS:
449 case MAD_UNITS_24_975_FPS:
450 case MAD_UNITS_29_97_FPS:
451 case MAD_UNITS_47_952_FPS:
452 case MAD_UNITS_49_95_FPS:
453 case MAD_UNITS_59_94_FPS:
454 if (fracunits < 0) {
455 /* not yet implemented */
456 sub = 0;
457 }
458
459 /* fall through */
460
461 case MAD_UNITS_DECISECONDS:
462 case MAD_UNITS_CENTISECONDS:
463 case MAD_UNITS_MILLISECONDS:
464
465 case MAD_UNITS_8000_HZ:
466 case MAD_UNITS_11025_HZ:
467 case MAD_UNITS_12000_HZ:
468 case MAD_UNITS_16000_HZ:
469 case MAD_UNITS_22050_HZ:
470 case MAD_UNITS_24000_HZ:
471 case MAD_UNITS_32000_HZ:
472 case MAD_UNITS_44100_HZ:
473 case MAD_UNITS_48000_HZ:
474
475 case MAD_UNITS_24_FPS:
476 case MAD_UNITS_25_FPS:
477 case MAD_UNITS_30_FPS:
478 case MAD_UNITS_48_FPS:
479 case MAD_UNITS_50_FPS:
480 case MAD_UNITS_60_FPS:
481 case MAD_UNITS_75_FPS:
482 sprintf(dest, format, mad_timer_count(timer, units), sub);
483 break;
484 }
485 }
486