/**
 * @file snd_mem.c
 * @brief Sound caching.
 */

/*
All original materal Copyright (C) 2002-2007 UFO: Alien Invasion team.

15/06/06, Eddy Cullen (ScreamingWithNoSound):
	Reformatted to agreed style.
	Added doxygen file comment.
	Updated copyright notice.

Original file from Quake 2 v3.21: quake2-2.31/client/snd_cache.c
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.

*/

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

/* #define DUMPCHUNKS */

static wavinfo_t GetWavinfo(char *name, byte * wav, int wavlength);

/**
 * @brief
 */
static void ResampleSfx (sfx_t * sfx, int inrate, int inwidth, byte * data)
{
	int outcount;
	int srcsample;
	float stepscale;
	int i;
	int sample, samplefrac, fracstep;
	sfxcache_t *sc;

	sc = sfx->cache;
	if (!sc)
		return;

	stepscale = (float) inrate / dma.speed;	/* this is usually 0.5, 1, or 2 */

	outcount = (int)(sc->length / stepscale);
	if (outcount == 0) {
		Com_Printf("ResampleSfx: Invalid sound file '%s' (zero length)\n", sfx->name);
		/* free at next opportunity */
		Mem_Free(sfx->cache);
		sfx->cache = NULL;
		return;
	}

	sc->length = outcount;

	if (sc->loopstart != -1)
		sc->loopstart = (int)(sc->loopstart / stepscale);

	sc->speed = dma.speed;
	if (snd_loadas8bit->value)
		sc->width = 1;
	else
		sc->width = inwidth;
	sc->stereo = 0;

	/* resample / decimate to the current source rate */
	if (stepscale == 1 && inwidth == 1 && sc->width == 1) {
		/* fast special case */
		for (i = 0; i < outcount; i++)
			((signed char *) sc->data)[i]
				= (int) ((unsigned char) (data[i]) - 128);
	} else {
		/* general case */
		samplefrac = 0;
		fracstep = stepscale * 256;
		for (i = 0; i < outcount; i++) {
			srcsample = samplefrac >> 8;
			samplefrac += fracstep;
			if (inwidth == 2)
				sample = LittleShort(((short *) data)[srcsample]);
			else
				sample = (int) ((unsigned char) (data[srcsample]) - 128) << 8;
			if (sc->width == 2)
				((short *) sc->data)[i] = sample;
			else
				((signed char *) sc->data)[i] = sample >> 8;
		}
	}
}

/**
 * @brief
 */
extern sfxcache_t *S_LoadSound (sfx_t * s)
{
	char namebuffer[MAX_QPATH];
	byte *data;
	wavinfo_t info;
	int len;
	float stepscale;
	sfxcache_t *sc;
	int size;
	char *name;

	if (s->name[0] == '*')
		return NULL;

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

	/*Com_Printf("S_LoadSound: %x\n", (int)stackbuf); */
	/* load it in */
	if (s->truename)
		name = s->truename;
	else
		name = s->name;

	if (name[0] == '#')
		Q_strncpyz(namebuffer, &name[1], MAX_QPATH);
	else
		Com_sprintf(namebuffer, sizeof(namebuffer), "sound/%s", name);

/*	Com_Printf("loading %s\n",namebuffer); */

	size = FS_LoadFile(namebuffer, (void **) (char *) &data);

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

	info = GetWavinfo(s->name, data, size);
	if (info.channels != 1) {
		Com_Printf("%s is a stereo sample\n", s->name);
		FS_FreeFile(data);
		return NULL;
	}

	stepscale = (float) info.rate / dma.speed;
	len = (int)(info.samples / stepscale);

	if (info.samples == 0) {
		Com_Printf("WARNING: Zero length sound encountered: %s\n", s->name);
		FS_FreeFile(data);
		return NULL;
	}

	len = len * info.width * info.channels;
	sc = s->cache = Mem_Alloc(len + sizeof(sfxcache_t));
	if (!sc) {
		FS_FreeFile(data);
		return NULL;
	}

	sc->length = info.samples;
	sc->loopstart = -1;			/*info.loopstart; */
	sc->speed = info.rate;
	sc->width = info.width;
	sc->stereo = info.channels;

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

	FS_FreeFile(data);

	return sc;
}



/*
===============================================================================
WAV loading
===============================================================================
*/


static byte *data_p;
static byte *iff_end;
static byte *last_chunk;
static byte *iff_data;
static int iff_chunk_len;

/**
 * @brief
 */
static short GetLittleShort (void)
{
	short val = 0;

#if 1
	val = *data_p;
	val = val + (*(data_p + 1) << 8);
#else
	val = LittleShort(*data_p);
#endif
	data_p += 2;
	return val;
}

/**
 * @brief
 */
static int GetLittleLong (void)
{
	int val = 0;

#if 1
	val = *data_p;
	val = val + (*(data_p + 1) << 8);
	val = val + (*(data_p + 2) << 16);
	val = val + (*(data_p + 3) << 24);
#else
	LittleLong(*data_p);
#endif
	data_p += 4;
	return val;
}

/**
 * @brief
 * @sa FindChunk
 */
static void FindNextChunk (const char *name)
{
	while (1) {
		data_p = last_chunk;

		data_p += 4;

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

		iff_chunk_len = GetLittleLong();
		if (iff_chunk_len < 0) {
			data_p = NULL;
			return;
		}
/*		if (iff_chunk_len > 1024*1024) */
/*			Sys_Error ("FindNextChunk: %i length is past the 1 meg sanity limit", iff_chunk_len); */
		data_p -= 8;
		last_chunk = data_p + 8 + ((iff_chunk_len + 1) & ~1);
		if (!Q_strncmp((char *) data_p, name, 4))
			return;
	}
}

/**
 * @brief
 * @sa FindNextChunk
 */
static void FindChunk (const char *name)
{
	last_chunk = iff_data;
	FindNextChunk(name);
}

#ifdef DUMPCHUNKS
/**
 * @brief
 */
static void DumpChunks (void)
{
	char str[5];

	str[4] = 0;
	data_p = iff_data;
	do {
		memcpy(str, data_p, 4);
		data_p += 4;
		iff_chunk_len = GetLittleLong();
		Com_Printf("0x%p : %s (%d)\n", (data_p - 4), str, iff_chunk_len);
		data_p += (iff_chunk_len + 1) & ~1;
	} while (data_p < iff_end);
}
#endif

/**
 * @brief
 */
static wavinfo_t GetWavinfo (char *name, byte * 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;
#ifdef DUMPCHUNKS
	DumpChunks();
#endif

	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();
/*		Com_Printf("loopstart=%d\n", sfx->loopstart); */

		/* if the next chunk is a LIST chunk, look for a cue length marker */
		FindNextChunk("LIST");
		if (data_p) {
			if ((data_p - wav) + 32 <= wavlength && !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;
/*				Com_Printf("looped length: %i\n", i); */
			}
		}
	} else
		info.loopstart = -1;

	/* find data chunk */
	FindChunk("data");
	if (!data_p) {
		Com_Printf("GetWavinfo: Missing data chunk (%s)\n", name);
		return info;
	}

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

	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 = (int)(data_p - wav);

	return info;
}