Diff: timer.cpp

Revision:

0:7627c79db971

Child:

2:f28cf0afd021

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/timer.cpp	Fri Nov 26 12:18:30 2010 +0000
@@ -0,0 +1,483 @@
+/*
+ * 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 1.1 2010/11/23 20:12:57 andy Exp $
+ */
+
+#  include "config.h"
+
+# 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, (enum mad_units)-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;
+  }
+}