// Enforce SFX cache size limit. We are just about to allocate "len"
// bytes on the heap for a new sound effect, so free up some space
// so that we keep allocated_sounds_size < snd_cachesize
static void ReserveCacheSpace(size_t len)
{
// Keep freeing sound effects that aren't currently being played,
// until there is enough space for the new sound.
while (allocated_sounds_size + len > CACHESIZE)
{
// Free a sound. If there is nothing more to free, stop.
if (!FindAndFreeSound())
break;
}
}
static Mix_Chunk *AllocateSound(sfxinfo_t *sfxinfo, size_t len)
{
allocated_sound_t *snd;
// Keep allocated sounds within the cache size.
ReserveCacheSpace(len);
// Allocate the sound structure and data. The data will immediately
// follow the structure, which acts as a header.
do
{
snd = malloc(sizeof(allocated_sound_t) + len);
// Out of memory? Try to free an old sound, then loop round
// and try again.
if (snd == NULL && !FindAndFreeSound())
{
return NULL;
}
} while (snd == NULL);
// Skip past the chunk structure for the audio buffer
snd->chunk.abuf = (byte *) (snd + 1);
snd->chunk.alen = len;
snd->chunk.allocated = 1;
snd->chunk.volume = MIX_MAX_VOLUME;
snd->sfxinfo = sfxinfo;
snd->use_count = 0;
// driver_data pointer points to the allocated_sound structure.
sfxinfo->driver_data = snd;
// Keep track of how much memory all these cached sounds are using...
allocated_sounds_size += len;
AllocatedSoundLink(snd);
return &snd->chunk;
}
