/*
Copyright (C) 1996-1997 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 "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);
}


#if 0
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", (int)(data_p - 4), str, iff_chunk_len);
    data_p += (iff_chunk_len + 1) & ~1;
  } while (data_p < iff_end);
}
#endif

/*
============
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;
}