virtch.c

这是著名的TCPMP播放器在WINDWOWS,和WINCE下编译通过的源程序.笔者对其中的LIBMAD库做了针对ARM MPU的优化. 并增加了词幕功能.

/*	MikMod sound library
	(c) 1998, 1999, 2000, 2001, 2002 Miodrag Vallat and others - see file
	AUTHORS for complete list.

	This library is free software; you can redistribute it and/or modify
	it under the terms of the GNU Library 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 Library General Public License for more details.
 
	You should have received a copy of the GNU Library General Public
	License along with this library; if not, write to the Free Software
	Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
	02111-1307, USA.
*/

/*==============================================================================

  $Id: virtch.c,v 1.2 2004/02/13 13:31:54 raph Exp $

  Sample mixing routines, using a 32 bits mixing buffer.

==============================================================================*/

/*

  Optional features include:
    (a) 4-step reverb (for 16 bit output only)
    (b) Interpolation of sample data during mixing
    (c) Dolby Surround Sound
*/

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <stddef.h>
#ifdef HAVE_MEMORY_H
#include <memory.h>
#endif
#include <string.h>

#include "mikmod_internals.h"

/*
   Constant definitions
   ====================

  	BITSHIFT
		Controls the maximum volume of the sound output.  All data is shifted
		right by BITSHIFT after being mixed. Higher values result in quieter
		sound and less chance of distortion.

	REVERBERATION
		Controls the duration of the reverb. Larger values represent a shorter
		reverb loop. Smaller values extend the reverb but can result in more of
		an echo-ish sound.

*/

#define BITSHIFT		9
#define REVERBERATION	110000L

#define FRACBITS 11
#define FRACMASK ((1L<<FRACBITS)-1L)

#define TICKLSIZE 8192
#define TICKWSIZE (TICKLSIZE<<1)
#define TICKBSIZE (TICKWSIZE<<1)

#define CLICK_SHIFT  6
#define CLICK_BUFFER (1L<<CLICK_SHIFT)

#ifndef MIN
#define MIN(a,b) (((a)<(b)) ? (a) : (b))
#endif

typedef struct VINFO {
	UBYTE     kick;              /* =1 -> sample has to be restarted */
	UBYTE     active;            /* =1 -> sample is playing */
	UWORD     flags;             /* 16/8 bits looping/one-shot */
	SWORD     handle;            /* identifies the sample */
	ULONG     start;             /* start index */
	ULONG     size;              /* samplesize */
	ULONG     reppos;            /* loop start */
	ULONG     repend;            /* loop end */
	ULONG     frq;               /* current frequency */
	int       vol;               /* current volume */
	int       pan;               /* current panning position */

	int       rampvol;
	int       lvolsel,rvolsel;   /* Volume factor in range 0-255 */
	int       oldlvol,oldrvol;

	SLONGLONG current;           /* current index in the sample */
	SLONGLONG increment;         /* increment value */
} VINFO;

static	SWORD **Samples;
static	VINFO *vinf=NULL,*vnf;
static	long tickleft,samplesthatfit,vc_memory=0;
static	int vc_softchn;
static	SLONGLONG idxsize,idxlpos,idxlend;
static	SLONG *vc_tickbuf=NULL;
static	UWORD vc_mode;

/* Reverb control variables */

static	int RVc1, RVc2, RVc3, RVc4, RVc5, RVc6, RVc7, RVc8;
static	ULONG RVRindex;

/* For Mono or Left Channel */
static	SLONG *RVbufL1=NULL,*RVbufL2=NULL,*RVbufL3=NULL,*RVbufL4=NULL,
		      *RVbufL5=NULL,*RVbufL6=NULL,*RVbufL7=NULL,*RVbufL8=NULL;

/* For Stereo only (Right Channel) */
static	SLONG *RVbufR1=NULL,*RVbufR2=NULL,*RVbufR3=NULL,*RVbufR4=NULL,
		      *RVbufR5=NULL,*RVbufR6=NULL,*RVbufR7=NULL,*RVbufR8=NULL;

#ifdef NATIVE_64BIT_INT
#define NATIVE SLONGLONG
#else
#define NATIVE SLONG
#endif

/*========== 32 bit sample mixers - only for 32 bit platforms */
#ifndef NATIVE_64BIT_INT

static SLONG Mix32MonoNormal(SWORD* srce,SLONG* dest,SLONG index,SLONG increment,SLONG todo)
{
	SWORD sample;
	SLONG lvolsel = vnf->lvolsel;

	while(todo--) {
		sample = srce[index >> FRACBITS];
		index += increment;

		*dest++ += lvolsel * sample;
	}
	return index;
}

static SLONG Mix32StereoNormal(SWORD* srce,SLONG* dest,SLONG index,SLONG increment,SLONG todo)
{
	SWORD sample;
	SLONG lvolsel = vnf->lvolsel;
	SLONG rvolsel = vnf->rvolsel;

	while(todo--) {
		sample=srce[index >> FRACBITS];
		index += increment;

		*dest++ += lvolsel * sample;
		*dest++ += rvolsel * sample;
	}
	return index;
}

static SLONG Mix32SurroundNormal(SWORD* srce,SLONG* dest,SLONG index,SLONG increment,SLONG todo)
{
	SWORD sample;
	SLONG lvolsel = vnf->lvolsel;
	SLONG rvolsel = vnf->rvolsel;

	if (lvolsel>=rvolsel) {
		while(todo--) {
			sample = srce[index >> FRACBITS];
			index += increment;

			*dest++ += lvolsel*sample;
			*dest++ -= lvolsel*sample;
		}
	} else {
		while(todo--) {
			sample = srce[index >> FRACBITS];
			index += increment;

			*dest++ -= rvolsel*sample;
			*dest++ += rvolsel*sample;
		}
	}
	return index;
}

static SLONG Mix32MonoInterp(SWORD* srce,SLONG* dest,SLONG index,SLONG increment,SLONG todo)
{
	SLONG sample;
	SLONG lvolsel = vnf->lvolsel;
	SLONG rampvol = vnf->rampvol;

	if (rampvol) {
		SLONG oldlvol = vnf->oldlvol - lvolsel;
		while(todo--) {
			sample=(SLONG)srce[index>>FRACBITS]+
			       ((SLONG)(srce[(index>>FRACBITS)+1]-srce[index>>FRACBITS])
			        *(index&FRACMASK)>>FRACBITS);
			index += increment;

			*dest++ += ((lvolsel << CLICK_SHIFT) + oldlvol * rampvol)
			           * sample >> CLICK_SHIFT;
			if (!--rampvol)
				break;
		}
		vnf->rampvol = rampvol;
		if (todo < 0)
			return index;
	}

	while(todo--) {
		sample=(SLONG)srce[index>>FRACBITS]+
		       ((SLONG)(srce[(index>>FRACBITS)+1]-srce[index>>FRACBITS])
		        *(index&FRACMASK)>>FRACBITS);
		index += increment;

		*dest++ += lvolsel * sample;
	}
	return index;
}

static SLONG Mix32StereoInterp(SWORD* srce,SLONG* dest,SLONG index,SLONG increment,SLONG todo)
{
	SLONG sample;
	SLONG lvolsel = vnf->lvolsel;
	SLONG rvolsel = vnf->rvolsel;
	SLONG rampvol = vnf->rampvol;

	if (rampvol) {
		SLONG oldlvol = vnf->oldlvol - lvolsel;
		SLONG oldrvol = vnf->oldrvol - rvolsel;
		while(todo--) {
			sample=(SLONG)srce[index>>FRACBITS]+
			       ((SLONG)(srce[(index>>FRACBITS)+1]-srce[index>>FRACBITS])
			        *(index&FRACMASK)>>FRACBITS);
			index += increment;

			*dest++ += ((lvolsel << CLICK_SHIFT) + oldlvol * rampvol)
			           * sample >> CLICK_SHIFT;
			*dest++ += ((rvolsel << CLICK_SHIFT) + oldrvol * rampvol)
					   * sample >> CLICK_SHIFT;
			if (!--rampvol)
				break;
		}
		vnf->rampvol = rampvol;
		if (todo < 0)
			return index;
	}

	while(todo--) {
		sample=(SLONG)srce[index>>FRACBITS]+
		       ((SLONG)(srce[(index>>FRACBITS)+1]-srce[index>>FRACBITS])
		        *(index&FRACMASK)>>FRACBITS);
		index += increment;

		*dest++ += lvolsel * sample;
		*dest++ += rvolsel * sample;
	}
	return index;
}

static SLONG Mix32SurroundInterp(SWORD* srce,SLONG* dest,SLONG index,SLONG increment,SLONG todo)
{
	SLONG sample;
	SLONG lvolsel = vnf->lvolsel;
	SLONG rvolsel = vnf->rvolsel;
	SLONG rampvol = vnf->rampvol;
	SLONG oldvol, vol;

	if (lvolsel >= rvolsel) {
		vol = lvolsel;
		oldvol = vnf->oldlvol;
	} else {
		vol = rvolsel;
		oldvol = vnf->oldrvol;
	}

	if (rampvol) {
		oldvol -= vol;
		while(todo--) {
			sample=(SLONG)srce[index>>FRACBITS]+
			       ((SLONG)(srce[(index>>FRACBITS)+1]-srce[index>>FRACBITS])
			        *(index&FRACMASK)>>FRACBITS);
			index += increment;

			sample=((vol << CLICK_SHIFT) + oldvol * rampvol)
				   * sample >> CLICK_SHIFT;
			*dest++ += sample;
			*dest++ -= sample;

			if (!--rampvol)
				break;
		}
		vnf->rampvol = rampvol;
		if (todo < 0)
			return index;
	}

	while(todo--) {
		sample=(SLONG)srce[index>>FRACBITS]+
		       ((SLONG)(srce[(index>>FRACBITS)+1]-srce[index>>FRACBITS])
		        *(index&FRACMASK)>>FRACBITS);
		index += increment;

		*dest++ += vol*sample;
		*dest++ -= vol*sample;
	}
	return index;
}
#endif

/*========== 64 bit sample mixers - all platforms */

static SLONGLONG MixMonoNormal(SWORD* srce,SLONG* dest,SLONGLONG index,SLONGLONG increment,SLONG todo)
{
	SWORD sample;
	SLONG lvolsel = vnf->lvolsel;

	while(todo--) {
		sample = srce[index >> FRACBITS];
		index += increment;

		*dest++ += lvolsel * sample;
	}
	return index;
}

static SLONGLONG MixStereoNormal(SWORD* srce,SLONG* dest,SLONGLONG index,SLONGLONG increment,SLONG todo)
{
	SWORD sample;
	SLONG lvolsel = vnf->lvolsel;
	SLONG rvolsel = vnf->rvolsel;

	while(todo--) {
		sample=srce[index >> FRACBITS];
		index += increment;

		*dest++ += lvolsel * sample;
		*dest++ += rvolsel * sample;
	}
	return index;
}

static SLONGLONG MixSurroundNormal(SWORD* srce,SLONG* dest,SLONGLONG index,SLONGLONG increment,SLONG todo)
{
	SWORD sample;
	SLONG lvolsel = vnf->lvolsel;
	SLONG rvolsel = vnf->rvolsel;

	if(vnf->lvolsel>=vnf->rvolsel) {
		while(todo--) {
			sample = srce[index >> FRACBITS];
			index += increment;

			*dest++ += lvolsel*sample;
			*dest++ -= lvolsel*sample;
		}
	} else {
		while(todo--) {
			sample = srce[index >> FRACBITS];
			index += increment;

			*dest++ -= rvolsel*sample;
			*dest++ += rvolsel*sample;
		}
	}
	return index;
}

static SLONGLONG MixMonoInterp(SWORD* srce,SLONG* dest,SLONGLONG index,SLONGLONG increment,SLONG todo)
{
	SLONG sample;
	SLONG lvolsel = vnf->lvolsel;
	SLONG rampvol = vnf->rampvol;

	if (rampvol) {
		SLONG oldlvol = vnf->oldlvol - lvolsel;
		while(todo--) {
			sample=(SLONG)srce[index>>FRACBITS]+
			       ((SLONG)(srce[(index>>FRACBITS)+1]-srce[index>>FRACBITS])
			        *(index&FRACMASK)>>FRACBITS);
			index += increment;

			*dest++ += ((lvolsel << CLICK_SHIFT) + oldlvol * rampvol)
					   * sample >> CLICK_SHIFT;
			if (!--rampvol)
				break;
		}
		vnf->rampvol = rampvol;
		if (todo < 0)
			return index;
	}

	while(todo--) {
		sample=(SLONG)srce[index>>FRACBITS]+
		       ((SLONG)(srce[(index>>FRACBITS)+1]-srce[index>>FRACBITS])
		        *(index&FRACMASK)>>FRACBITS);
		index += increment;

		*dest++ += lvolsel * sample;
	}
	return index;
}

static SLONGLONG MixStereoInterp(SWORD* srce,SLONG* dest,SLONGLONG index,SLONGLONG increment,SLONG todo)
{
	SLONG sample;
	SLONG lvolsel = vnf->lvolsel;
	SLONG rvolsel = vnf->rvolsel;
	SLONG rampvol = vnf->rampvol;

	if (rampvol) {
		SLONG oldlvol = vnf->oldlvol - lvolsel;
		SLONG oldrvol = vnf->oldrvol - rvolsel;
		while(todo--) {
			sample=(SLONG)srce[index>>FRACBITS]+
			       ((SLONG)(srce[(index>>FRACBITS)+1]-srce[index>>FRACBITS])
			        *(index&FRACMASK)>>FRACBITS);
			index += increment;

			*dest++ +=((lvolsel << CLICK_SHIFT) + oldlvol * rampvol)
					   * sample >> CLICK_SHIFT;
			*dest++ +=((rvolsel << CLICK_SHIFT) + oldrvol * rampvol)
					   * sample >> CLICK_SHIFT;
			if (!--rampvol)
				break;
		}
		vnf->rampvol = rampvol;
		if (todo < 0)
			return index;
	}

	while(todo--) {
		sample=(SLONG)srce[index>>FRACBITS]+
		       ((SLONG)(srce[(index>>FRACBITS)+1]-srce[index>>FRACBITS])
		        *(index&FRACMASK)>>FRACBITS);
		index += increment;

		*dest++ += lvolsel * sample;
		*dest++ += rvolsel * sample;
	}
	return index;
}

static SLONGLONG MixSurroundInterp(SWORD* srce,SLONG* dest,SLONGLONG index,SLONGLONG increment,SLONG todo)
{
	SLONG sample;
	SLONG lvolsel = vnf->lvolsel;
	SLONG rvolsel = vnf->rvolsel;
	SLONG rampvol = vnf->rampvol;
	SLONG oldvol, vol;

	if (lvolsel >= rvolsel) {
		vol = lvolsel;
		oldvol = vnf->oldlvol;
	} else {
		vol = rvolsel;
		oldvol = vnf->oldrvol;
	}

	if (rampvol) {
		oldvol -= vol;
		while(todo--) {
			sample=(SLONG)srce[index>>FRACBITS]+
			       ((SLONG)(srce[(index>>FRACBITS)+1]-srce[index>>FRACBITS])
			        *(index&FRACMASK)>>FRACBITS);
			index += increment;

			sample=((vol << CLICK_SHIFT) + oldvol * rampvol)
				   * sample >> CLICK_SHIFT;
			*dest++ += sample;
			*dest++ -= sample;
			if (!--rampvol)
				break;
		}
		vnf->rampvol = rampvol;
		if (todo < 0)
			return index;
	}

	while(todo--) {
		sample=(SLONG)srce[index>>FRACBITS]+
		       ((SLONG)(srce[(index>>FRACBITS)+1]-srce[index>>FRACBITS])