snd_mem.c

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/*
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"
 
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 = sfx->cache;
    if (!sc)
        return;
 
    stepscale = (float)inrate / dma.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 = dma.speed;
    if (s_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[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] == '#')
        strcpy(namebuffer, &name[1]);
    else
        Com_sprintf (namebuffer, sizeof(namebuffer), "sound/%s", name);
 
//  Com_Printf ("loading %s\n",namebuffer);
 
    size = FS_LoadFile (namebuffer, (void **)&data);
 
    if (!data)
    {
        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 = info.samples / stepscale;
 
    len = len * info.width * info.channels;
 
    sc = s->cache = Z_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->width = info.width;
    sc->stereo = info.channels;
 
    ResampleSfx (s, sc->speed, sc->width, data + info.dataofs);
 
    FS_FreeFile (data);
 
    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 (!strncmp((char *)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();
        Com_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);
}
 
/*
============
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 && !strncmp((char *)data_p+8, "WAVE", 4)))
    {
        Com_Printf("Missing RIFF/WAVE chunks\n");
        return info;
    }
 
// get "fmt " chunk
    iff_data = data_p + 12;
// DumpChunks ();
 
    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 (!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("Missing data chunk\n");
        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 = data_p - wav;
    
    return info;
}