source: downloads/openal-0.0.8/src/al_mspool.c @ 17

/* -*- mode: C; tab-width:8; c-basic-offset:8 -*-
 * vi:set ts=8:
 *
 * al_mspool.c
 *
 * Prototypes, macros and definitions related to the management of mspool
 * objects.  mspool objects are objects which ease the slab allocation of
 * _alMixSource objects.
 */
#include "al_debug.h"
#include "al_mspool.h"

#include <stdlib.h>

#define MIN(a,b) ((a) < (b) ? (a) : (b))
#define MAX(a,b) ((a) > (b) ? (a) : (b))

/*
 * _alMixPoolResize( _alMixPool *mspool, size_t newsize )
 *
 * Initializes an already allocated _alMixPool object.  Returns AL_TRUE,
 * inless initialization failed for some reason, in which case AL_FALSE is
 * returned.
 *
 * After a successful initialization, mspool will have the capacity for at
 * least newsize _alMixPoolNodes.
 */
ALboolean _alMixPoolResize(_alMixPool *spool, size_t newsize)
{
        _alMixPoolNode *temp;
        unsigned int i;

        newsize = MAX( newsize, 1 );

        if(spool->size >= newsize)
        {
                return AL_TRUE; /* no resize needed */
        }

        if(spool->pool == NULL)
        {
                spool->pool = malloc(newsize * sizeof *spool->pool);
        }
        else
        {
                temp = realloc(spool->pool, newsize * sizeof(_alMixPoolNode));
                if(temp == NULL)
                {
                        return AL_FALSE; /* could not realloc */
                }

                spool->pool = temp;
        }

        for(i = spool->size; i < newsize; i++)
        {
                spool->pool[i].inuse = AL_FALSE;
        }

        spool->size = newsize;

        return AL_TRUE;
}

/*
 * _alMixPoolAlloc( _alMixPool *mspool )
 *
 * Initializes an already allocated _alMixPool object.  Returns index suitable
 * for calls which expect an index, or -1 on error.
 */
int _alMixPoolAlloc( _alMixPool *spool )
{
        int msindex;

        msindex = _alMixPoolFirstFreeIndex(spool);
        if(msindex == -1)
        {
                if(_alMixPoolResize(spool, spool->size * 2) == AL_FALSE)
                {
                        return -1;
                }

                msindex = _alMixPoolFirstFreeIndex(spool);
        }

        spool->pool[msindex].inuse = AL_TRUE;

        return msindex;
}

/*
 * _alMixPoolIndex( _alMixPool *mspool, int msindex )
 *
 * Return _alMixSource from mspool using simple index, or NULL if msindex is
 * not a valid index or has not been flagged for use.
 */
_alMixSource *_alMixPoolIndex(_alMixPool *spool, int msindex)
{
        if( msindex > (int) spool->size )
        {
                return NULL;
        }

        if(spool->pool[msindex].inuse == AL_FALSE)
        {
                return NULL;
        }

        return &spool->pool[msindex].data;
}

/*
 * _alMixPoolFirstFreeIndex( _alMixPool *mspool )
 *
 * Returns first available index in mspool, or -1 if nothing is available.
 */
int _alMixPoolFirstFreeIndex(_alMixPool *spool)
{
        ALuint i;

        for(i = 0; i < spool->size; i++)
        {
                if(spool->pool[i].inuse == AL_FALSE)
                {
                        return i;
                }
        }

        return -1;
}

/*
 * _alMixPoolDealloc( _alMixPool *mspool, int msindex,
 *                   void (*freer_func)(void *))
 *
 * Finalize a _alMixSource, indexed by msindex, using freer_func,
 * from mspool, marking is as not in use.
 */
ALboolean _alMixPoolDealloc( _alMixPool *spool, int msindex,
                             void (*freer_func)(void *) ) {
        _alMixSource *src;

        if( msindex < 0 ) {
                return AL_FALSE;
        }

        src = _alMixPoolIndex( spool, msindex );
        if(src == NULL) {
                _alDebug(ALD_MIXER, __FILE__, __LINE__,
                        "%d is a bad index", msindex);

                return AL_FALSE;
        }

        spool->pool[msindex].inuse = AL_FALSE;

        freer_func(src);

        return AL_TRUE;
}

/*
 * _alMixPoolFree( _alMixPool *mspool, void (*freer_func)(void *) )
 *
 * Finalizes each _alMixSource in the _alMixPool object, using freer_func.
 */
void _alMixPoolFree(_alMixPool *spool, void (*freer_func)(void *))
{
        unsigned int i;

        for(i = 0; i < spool->size; i++)
        {
                if(spool->pool[i].inuse == AL_TRUE)
                {
                        _alMixPoolDealloc( spool, i, freer_func );
                }
        }

        free( spool->pool );
        spool->pool = NULL;

        spool->size = 0;

        /* let the caller free spool itself */

        return;
}