/* * libmad - MPEG audio decoder library * Copyright (C) 2000-2004 Underbit Technologies, Inc. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA * * $Id: timer.c,v 1.18 2004/01/23 09:41:33 rob Exp $ */ # ifdef HAVE_CONFIG_H # include "config.h" # endif # include "global.h" # include <stdio.h> # ifdef HAVE_ASSERT_H # include <assert.h> # endif # include "timer.h" mad_timer_t const mad_timer_zero = { 0, 0 }; /* * NAME: timer->compare() * DESCRIPTION: indicate relative order of two timers */ int mad_timer_compare(mad_timer_t timer1, mad_timer_t timer2) { signed long diff; diff = timer1.seconds - timer2.seconds; if (diff < 0) return -1; else if (diff > 0) return +1; diff = timer1.fraction - timer2.fraction; if (diff < 0) return -1; else if (diff > 0) return +1; return 0; } /* * NAME: timer->negate() * DESCRIPTION: invert the sign of a timer */ void mad_timer_negate(mad_timer_t *timer) { timer->seconds = -timer->seconds; if (timer->fraction) { timer->seconds -= 1; timer->fraction = MAD_TIMER_RESOLUTION - timer->fraction; } } /* * NAME: timer->abs() * DESCRIPTION: return the absolute value of a timer */ mad_timer_t mad_timer_abs(mad_timer_t timer) { if (timer.seconds < 0) mad_timer_negate(&timer); return timer; } /* * NAME: reduce_timer() * DESCRIPTION: carry timer fraction into seconds */ static void reduce_timer(mad_timer_t *timer) { timer->seconds += timer->fraction / MAD_TIMER_RESOLUTION; timer->fraction %= MAD_TIMER_RESOLUTION; } /* * NAME: gcd() * DESCRIPTION: compute greatest common denominator */ static unsigned long gcd(unsigned long num1, unsigned long num2) { unsigned long tmp; while (num2) { tmp = num2; num2 = num1 % num2; num1 = tmp; } return num1; } /* * NAME: reduce_rational() * DESCRIPTION: convert rational expression to lowest terms */ static void reduce_rational(unsigned long *numer, unsigned long *denom) { unsigned long factor; factor = gcd(*numer, *denom); assert(factor != 0); *numer /= factor; *denom /= factor; } /* * NAME: scale_rational() * DESCRIPTION: solve numer/denom == ?/scale avoiding overflowing */ static unsigned long scale_rational(unsigned long numer, unsigned long denom, unsigned long scale) { reduce_rational(&numer, &denom); reduce_rational(&scale, &denom); assert(denom != 0); if (denom < scale) return numer * (scale / denom) + numer * (scale % denom) / denom; if (denom < numer) return scale * (numer / denom) + scale * (numer % denom) / denom; return numer * scale / denom; } /* * NAME: timer->set() * DESCRIPTION: set timer to specific (positive) value */ void mad_timer_set(mad_timer_t *timer, unsigned long seconds, unsigned long numer, unsigned long denom) { timer->seconds = seconds; if (numer >= denom && denom > 0) { timer->seconds += numer / denom; numer %= denom; } switch (denom) { case 0: case 1: timer->fraction = 0; break; case MAD_TIMER_RESOLUTION: timer->fraction = numer; break; case 1000: timer->fraction = numer * (MAD_TIMER_RESOLUTION / 1000); break; case 8000: timer->fraction = numer * (MAD_TIMER_RESOLUTION / 8000); break; case 11025: timer->fraction = numer * (MAD_TIMER_RESOLUTION / 11025); break; case 12000: timer->fraction = numer * (MAD_TIMER_RESOLUTION / 12000); break; case 16000: timer->fraction = numer * (MAD_TIMER_RESOLUTION / 16000); break; case 22050: timer->fraction = numer * (MAD_TIMER_RESOLUTION / 22050); break; case 24000: timer->fraction = numer * (MAD_TIMER_RESOLUTION / 24000); break; case 32000: timer->fraction = numer * (MAD_TIMER_RESOLUTION / 32000); break; case 44100: timer->fraction = numer * (MAD_TIMER_RESOLUTION / 44100); break; case 48000: timer->fraction = numer * (MAD_TIMER_RESOLUTION / 48000); break; default: timer->fraction = scale_rational(numer, denom, MAD_TIMER_RESOLUTION); break; } if (timer->fraction >= MAD_TIMER_RESOLUTION) reduce_timer(timer); } /* * NAME: timer->add() * DESCRIPTION: add one timer to another */ void mad_timer_add(mad_timer_t *timer, mad_timer_t incr) { timer->seconds += incr.seconds; timer->fraction += incr.fraction; if (timer->fraction >= MAD_TIMER_RESOLUTION) reduce_timer(timer); } /* * NAME: timer->multiply() * DESCRIPTION: multiply a timer by a scalar value */ void mad_timer_multiply(mad_timer_t *timer, signed long scalar) { mad_timer_t addend; unsigned long factor; factor = scalar; if (scalar < 0) { factor = -scalar; mad_timer_negate(timer); } addend = *timer; *timer = mad_timer_zero; while (factor) { if (factor & 1) mad_timer_add(timer, addend); mad_timer_add(&addend, addend); factor >>= 1; } } /* * NAME: timer->count() * DESCRIPTION: return timer value in selected units */ signed long mad_timer_count(mad_timer_t timer, enum mad_units units) { switch (units) { case MAD_UNITS_HOURS: return timer.seconds / 60 / 60; case MAD_UNITS_MINUTES: return timer.seconds / 60; case MAD_UNITS_SECONDS: return timer.seconds; case MAD_UNITS_DECISECONDS: case MAD_UNITS_CENTISECONDS: case MAD_UNITS_MILLISECONDS: case MAD_UNITS_8000_HZ: case MAD_UNITS_11025_HZ: case MAD_UNITS_12000_HZ: case MAD_UNITS_16000_HZ: case MAD_UNITS_22050_HZ: case MAD_UNITS_24000_HZ: case MAD_UNITS_32000_HZ: case MAD_UNITS_44100_HZ: case MAD_UNITS_48000_HZ: case MAD_UNITS_24_FPS: case MAD_UNITS_25_FPS: case MAD_UNITS_30_FPS: case MAD_UNITS_48_FPS: case MAD_UNITS_50_FPS: case MAD_UNITS_60_FPS: case MAD_UNITS_75_FPS: return timer.seconds * (signed long) units + (signed long) scale_rational(timer.fraction, MAD_TIMER_RESOLUTION, units); case MAD_UNITS_23_976_FPS: case MAD_UNITS_24_975_FPS: case MAD_UNITS_29_97_FPS: case MAD_UNITS_47_952_FPS: case MAD_UNITS_49_95_FPS: case MAD_UNITS_59_94_FPS: return (mad_timer_count(timer, -units) + 1) * 1000 / 1001; } /* unsupported units */ return 0; } /* * NAME: timer->fraction() * DESCRIPTION: return fractional part of timer in arbitrary terms */ unsigned long mad_timer_fraction(mad_timer_t timer, unsigned long denom) { timer = mad_timer_abs(timer); switch (denom) { case 0: return timer.fraction ? MAD_TIMER_RESOLUTION / timer.fraction : MAD_TIMER_RESOLUTION + 1; case MAD_TIMER_RESOLUTION: return timer.fraction; default: return scale_rational(timer.fraction, MAD_TIMER_RESOLUTION, denom); } } /* * NAME: timer->string() * DESCRIPTION: write a string representation of a timer using a template */ void mad_timer_string(mad_timer_t timer, char *dest, char const *format, enum mad_units units, enum mad_units fracunits, unsigned long subparts) { unsigned long hours, minutes, seconds, sub; unsigned int frac; timer = mad_timer_abs(timer); seconds = timer.seconds; frac = sub = 0; switch (fracunits) { case MAD_UNITS_HOURS: case MAD_UNITS_MINUTES: case MAD_UNITS_SECONDS: break; case MAD_UNITS_DECISECONDS: case MAD_UNITS_CENTISECONDS: case MAD_UNITS_MILLISECONDS: case MAD_UNITS_8000_HZ: case MAD_UNITS_11025_HZ: case MAD_UNITS_12000_HZ: case MAD_UNITS_16000_HZ: case MAD_UNITS_22050_HZ: case MAD_UNITS_24000_HZ: case MAD_UNITS_32000_HZ: case MAD_UNITS_44100_HZ: case MAD_UNITS_48000_HZ: case MAD_UNITS_24_FPS: case MAD_UNITS_25_FPS: case MAD_UNITS_30_FPS: case MAD_UNITS_48_FPS: case MAD_UNITS_50_FPS: case MAD_UNITS_60_FPS: case MAD_UNITS_75_FPS: { unsigned long denom; denom = MAD_TIMER_RESOLUTION / fracunits; frac = timer.fraction / denom; sub = scale_rational(timer.fraction % denom, denom, subparts); } break; case MAD_UNITS_23_976_FPS: case MAD_UNITS_24_975_FPS: case MAD_UNITS_29_97_FPS: case MAD_UNITS_47_952_FPS: case MAD_UNITS_49_95_FPS: case MAD_UNITS_59_94_FPS: /* drop-frame encoding */ /* N.B. this is only well-defined for MAD_UNITS_29_97_FPS */ { unsigned long frame, cycle, d, m; frame = mad_timer_count(timer, fracunits); cycle = -fracunits * 60 * 10 - (10 - 1) * 2; d = frame / cycle; m = frame % cycle; frame += (10 - 1) * 2 * d; if (m > 2) frame += 2 * ((m - 2) / (cycle / 10)); frac = frame % -fracunits; seconds = frame / -fracunits; } break; } switch (units) { case MAD_UNITS_HOURS: minutes = seconds / 60; hours = minutes / 60; sprintf(dest, format, hours, (unsigned int) (minutes % 60), (unsigned int) (seconds % 60), frac, sub); break; case MAD_UNITS_MINUTES: minutes = seconds / 60; sprintf(dest, format, minutes, (unsigned int) (seconds % 60), frac, sub); break; case MAD_UNITS_SECONDS: sprintf(dest, format, seconds, frac, sub); break; case MAD_UNITS_23_976_FPS: case MAD_UNITS_24_975_FPS: case MAD_UNITS_29_97_FPS: case MAD_UNITS_47_952_FPS: case MAD_UNITS_49_95_FPS: case MAD_UNITS_59_94_FPS: if (fracunits < 0) { /* not yet implemented */ sub = 0; } /* fall through */ case MAD_UNITS_DECISECONDS: case MAD_UNITS_CENTISECONDS: case MAD_UNITS_MILLISECONDS: case MAD_UNITS_8000_HZ: case MAD_UNITS_11025_HZ: case MAD_UNITS_12000_HZ: case MAD_UNITS_16000_HZ: case MAD_UNITS_22050_HZ: case MAD_UNITS_24000_HZ: case MAD_UNITS_32000_HZ: case MAD_UNITS_44100_HZ: case MAD_UNITS_48000_HZ: case MAD_UNITS_24_FPS: case MAD_UNITS_25_FPS: case MAD_UNITS_30_FPS: case MAD_UNITS_48_FPS: case MAD_UNITS_50_FPS: case MAD_UNITS_60_FPS: case MAD_UNITS_75_FPS: sprintf(dest, format, mad_timer_count(timer, units), sub); break; } }