// snd_mem.c: sound caching

#include "quakedef.h"

int cache_full_cycle;

byte *S_Alloc(int size);

/*
================
ResampleSfx
================
*/
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 = Cache_Check(&sfx->cache);
    if (!sc)
	return;

    stepscale = (float) inrate / shm->speed;	// this is usually 0.5, 1, or 2

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

    sc->speed = shm->speed;
    if (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;
	}
    }
}

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

/*
==============
S_LoadSound
==============
*/
sfxcache_t *S_LoadSound(sfx_t * s)
{
    char namebuffer[256];
    byte *data;
    wavinfo_t info;
    int len;
    float stepscale;
    sfxcache_t *sc;
    byte stackbuf[1 * 1024];	// avoid dirtying the cache heap

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

//Con_Printf ("S_LoadSound: %x\n", (int)stackbuf);
// load it in
    Q_strcpy(namebuffer, "sound/");
    Q_strcat(namebuffer, s->name);

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

    data = COM_LoadStackFile(namebuffer, stackbuf, sizeof(stackbuf));

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

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

    stepscale = (float) info.rate / shm->speed;
    len = info.samples / stepscale;

    len = len * info.width * info.channels;

    sc = Cache_Alloc(&s->cache, len + sizeof(sfxcache_t), s->name);
    if (!sc)
	return NULL;

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

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

    return sc;
}



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

WAV loading

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


byte *data_p;
byte *iff_end;
byte *last_chunk;
byte *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;
	}
//              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(data_p, name, 4))
	    return;
    }
}

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


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();
	Con_Printf("0x%x : %s (%d)\n", (long) (data_p - 4), str,
		   iff_chunk_len);
	data_p += (iff_chunk_len + 1) & ~1;
    } while (data_p < iff_end);
}

/*
============
GetWavinfo
============
*/
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 && !Q_strncmp(data_p + 8, "WAVE", 4))) {
	Con_Printf("Missing RIFF/WAVE chunks\n");
	return info;
    }
// get "fmt " chunk
    iff_data = data_p + 12;
// DumpChunks ();

    FindChunk("fmt ");
    if (!data_p) {
	Con_Printf("Missing fmt chunk\n");
	return info;
    }
    data_p += 8;
    format = GetLittleShort();
    if (format != 1) {
	Con_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();
//              Con_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 (!strncmp(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;
//                              Con_Printf("looped length: %i\n", i);
	    }
	}
    } else
	info.loopstart = -1;

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

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

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

    info.dataofs = data_p - wav;

    return info;
}
