/*
Copyright (C) 1997-2001 Id Software, 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.

*/
// snd_mem.c: sound caching

#include "client.h"
#include "snd_loc.h"

/*
================
ResampleSfx
================
*/
void ResampleSfx (sfxcache_t *sc, qbyte *data, char *name)
{
	int i, srclength, outcount, fracstep, chancount;
	int	samplefrac, srcsample, srcnextsample;

	// this is usually 0.5 (128), 1 (256), or 2 (512)
	fracstep = ((double) sc->speed / (double) dma.speed) * 256.0;

	chancount = sc->channels - 1;
	srclength = sc->length / sc->channels;
	outcount = (double) sc->length * (double) dma.speed / (double) sc->speed;

	sc->length = outcount;
	if (sc->loopstart != -1)
		sc->loopstart = (double) sc->loopstart * (double) dma.speed / (double) sc->speed;

	sc->speed = dma.speed;

// resample / decimate to the current source rate
	if (fracstep == 256)
	{
		if (sc->width == 2)
			for (i = 0; i < srclength; i++)
				((short *)sc->data)[i] = LittleShort (((short *)data)[i]);
		else // 8bit
			for (i = 0; i < srclength; i++)
				((signed char *)sc->data)[i] = ((unsigned char *)data)[i] - 128;
	}
	else
	{
		int j, a, b, sample;

// general case
		Com_DPrintf("ResampleSfx: resampling sound %s\n", name);
		samplefrac = 0;
		srcsample = 0;
		srcnextsample = sc->channels;
		outcount *= sc->channels;

#define RESAMPLE_AND_ADVANCE	\
				sample = (((b - a) * (samplefrac & 255)) >> 8) + a; \
				if (j == chancount) \
				{ \
					samplefrac += fracstep; \
					srcsample = (samplefrac >> 8) << chancount; \
					srcnextsample = srcsample + sc->channels; \
				}

		if (sc->width == 2)
		{
			short *out = (void *)sc->data, *in = (void *)data;

			for (i = 0, j = 0; i < outcount; i++, j = i & chancount)
			{
				a = LittleShort (in[srcsample + j]);
				b = ((srcnextsample < srclength) ? LittleShort (in[srcnextsample + j]) : 0);
				RESAMPLE_AND_ADVANCE;
				*out++ = (short)sample;
			}
		}
		else
		{
			signed char *out = (void *)sc->data;
			unsigned char *in = (void *)data;

			for (i = 0, j = 0; i < outcount; i++, j = i & chancount)
			{
				a = (int)in[srcsample + j] - 128;
				b = ((srcnextsample < srclength) ? (int)in[srcnextsample + j] - 128 : 0);
				RESAMPLE_AND_ADVANCE;
				*out++ = (signed char)sample;
			}
		}
	}
}


//=============================================================================

/*
==============
S_LoadSound
==============
*/
sfxcache_t *S_LoadSound (sfx_t *s)
{
    char	namebuffer[MAX_QPATH];
	qbyte	*data;
	wavinfo_t	info;
	int		len;
	sfxcache_t	*sc;
	int		size;

	if (!s->name[0])
		return NULL;

// see if still in memory
	sc = s->cache;
	if (sc)
		return sc;

// load it in
	Q_strncpyz (namebuffer, s->name, sizeof(namebuffer));
	size = FS_LoadFile (namebuffer, (void **)&data, NULL, 0);

	if (!data)
	{
		Com_DPrintf ("Couldn't load %s\n", namebuffer);
		return NULL;
	}

	info = GetWavinfo (s->name, data, size);
	if (info.channels < 1 || info.channels > 2)
	{
		Com_Printf ("%s has an invalid number of channels\n", s->name);
		FS_FreeFile (data);
		return NULL;
	}

	// calculate resampled length
	len = (int) ((double) info.samples * (double) dma.speed / (double) info.rate);
	len = len * info.width * info.channels;

	sc = s->cache = S_Malloc (len + sizeof(sfxcache_t));
	if (!sc)
	{
		FS_FreeFile (data);
		return NULL;
	}

	sc->length = info.samples;
	sc->loopstart = info.loopstart;
	sc->speed = info.rate;
	sc->channels = info.channels;
	sc->width = info.width;

	ResampleSfx (sc, data + info.dataofs, s->name);

	FS_FreeFile (data);

	return sc;
}



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

WAV loading

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


qbyte	*data_p;
qbyte 	*iff_end;
qbyte 	*last_chunk;
qbyte 	*iff_data;
int 	iff_chunk_len;


short GetLittleShort(void)
{
	short val = 0;
	val = *data_p;
	val = val + (*(data_p+1)<<8);
	data_p += 2;
	return val;
}

int GetLittleLong(void)
{
	int val = 0;
	val = *data_p;
	val = val + (*(data_p+1)<<8);
	val = val + (*(data_p+2)<<16);
	val = val + (*(data_p+3)<<24);
	data_p += 4;
	return val;
}

void FindNextChunk(char *name)
{
	while (1)
	{
		data_p = last_chunk;

		if (data_p >= iff_end)
		{	// didn't find the chunk
			data_p = NULL;
			return;
		}

		data_p += 4;
		iff_chunk_len = GetLittleLong();
		if (iff_chunk_len < 0)
		{
			data_p = NULL;
			return;
		}

		data_p -= 8;
		last_chunk = data_p + 8 + ( (iff_chunk_len + 1) & ~1 );
		if (!strncmp((char *) data_p, name, 4))
			return;
	}
}

void FindChunk(char *name)
{
	last_chunk = iff_data;
	FindNextChunk (name);
}

/*
============
GetWavinfo
============
*/
wavinfo_t GetWavinfo (char *name, qbyte *wav, int wavlength)
{
	wavinfo_t	info;
	int     i;
	int     format;
	int		samples;

	memset (&info, 0, sizeof(info));

	if (!wav)
		return info;

	iff_data = wav;
	iff_end = wav + wavlength;

// find "RIFF" chunk
	FindChunk("RIFF");
	if (!(data_p && !strncmp((char *) data_p+8, "WAVE", 4)))
	{
		Com_Printf("Missing RIFF/WAVE chunks\n");
		return info;
	}

// get "fmt " chunk
	iff_data = data_p + 12;

	FindChunk("fmt ");
	if (!data_p)
	{
		Com_Printf("Missing fmt chunk\n");
		return info;
	}

	data_p += 8;
	format = GetLittleShort();
	if (format != 1)
	{
		Com_Printf("Microsoft PCM format only\n");
		return info;
	}

	info.channels = GetLittleShort();
	info.rate = GetLittleLong();
	data_p += 4+2;
	info.width = GetLittleShort() / 8;

// get cue chunk
	FindChunk("cue ");
	if (data_p)
	{
		data_p += 32;
		info.loopstart = GetLittleLong();

	// if the next chunk is a LIST chunk, look for a cue length marker
		FindNextChunk ("LIST");
		if (data_p)
		{
			if (!strncmp ((char *) data_p + 28, "mark", 4))
			{	// this is not a proper parse, but it works with cooledit...
				data_p += 24;
				i = GetLittleLong ();	// samples in loop
				info.samples = info.loopstart + i;
			}
		}
	}
	else
		info.loopstart = -1;

// find data chunk
	FindChunk("data");
	if (!data_p)
	{
		Com_Printf("Missing data chunk\n");
		return info;
	}

	data_p += 4;
	samples = GetLittleLong () / info.width / info.channels;

	if (info.samples)
	{
		if (samples < info.samples)
			Com_Error (ERR_DROP, "Sound %s has a bad loop length", name);
	}
	else
		info.samples = samples;

	info.dataofs = data_p - wav;

	return info;
}

