/* Copyright (c) 2009 The Khronos Group Inc.

 *

 * Permission is hereby granted, free of charge, to any person obtaining a

 * copy of this software and/or associated documentation files (the

 * "Materials"), to deal in the Materials without restriction, including

 * without limitation the rights to use, copy, modify, merge, publish,

 * distribute, sublicense, and/or sell copies of the Materials, and to

 * permit persons to whom the Materials are furnished to do so, subject to

 * the following conditions:

 *

 * The above copyright notice and this permission notice shall be included

 * in all copies or substantial portions of the Materials.

 *

 * THE MATERIALS ARE PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,

 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF

 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.

 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY

 * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,

 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE

 * MATERIALS OR THE USE OR OTHER DEALINGS IN THE MATERIALS.

 */

 /*

 * owfpool.c

 */

#ifdef __cplusplus

extern "C"

{

#endif

#include <string.h>

#include <stdio.h>

#include <stdlib.h>

#include "owfdebug.h"

#include "owftypes.h"

#include "owfpool.h"

#include "owfmemory.h"

OWF_API_CALL OWF_POOL*

OWF_Pool_Create(size_t objectSize, size_t objectCount)

{

    OWF_POOL*               pool;

    char*                   chunk;

    OWFuint32*               entries;

    /* we be needing some memories, aye */

    pool    = (OWF_POOL*)xalloc(sizeof(OWF_POOL), 1);

    entries = (OWFuint32*)xalloc(sizeof(OWFuint32), objectCount);

    chunk   = (char*)xalloc((objectSize + sizeof(OWFuint32*)), objectCount);

    if (pool && entries && chunk)

    {

        size_t              i;

        /* setup pool */

        pool->entries   = entries;

        pool->chunk     = chunk;

        pool->capacity  =

        pool->free      = objectCount;

        pool->firstFree = 0;

        pool->entrySize = objectSize;

        /* initially all objects are marked as free */

        for (i = 0; i < objectCount-1; i++) {

            entries[i] = i+1;

        }

        /* terminate chain */

        entries[objectCount-1] = EOC;

    }

    else

    {

        /* failed miserably. bail out. */

        xfree(pool);

        pool = NULL;

        xfree(entries);

        xfree(chunk);

    }

    return pool;

}

OWF_API_CALL void*

OWF_Pool_GetObject(OWF_POOL* pool)

{

    void*                   object = NULL;

    if (pool)

    {

        /* we have objects left in the pool? */

        if (pool->firstFree != EOC)

        {

            OWFuint32*       temp;

            OWFuint32        chunk;

            chunk = (OWFuint32) pool->chunk;

            /* calculate offset inside the chunk */

            temp = (OWFuint32*) (chunk + (pool->entrySize +

                    sizeof(OWFuint32*)) * pool->firstFree);

            /* remember way back to home */

            temp[0] = (OWFuint32) pool;

            object = (void*) &temp[1];

            pool->firstFree = pool->entries[pool->firstFree];

            --pool->free;

            OWF_ASSERT((OWFuint32) object > (OWFuint32) pool->chunk);

            OWF_ASSERT((int)object != 0x5eaf00d);

        }

    }

    return object;

}

OWF_API_CALL void

OWF_Pool_PutObject(void* object)

{

    OWFuint32* temp = (OWFuint32*) object;

    if (temp && temp[-1])

    {

        OWF_POOL*           pool;

        OWFuint32            addr;

        OWFuint32            chunk;

        OWFuint32            entrySize;

        addr    = (OWFuint32) object - 4;

        pool    = (OWF_POOL*) temp[-1];

        chunk   = (OWFuint32) pool->chunk;

        entrySize = pool->entrySize + sizeof(OWFuint32*);

        if (addr >= chunk &&

            addr < (chunk + pool->capacity * entrySize))

        {

            OWFuint32 index = (addr - chunk) / entrySize;

            pool->entries[index] = pool->firstFree;

            pool->firstFree = index;

            memset(object, 0x0, pool->entrySize);

            ++pool->free;

        }

        else

        {

            /* invalid object */

            OWF_ASSERT(0);

        }

    }

}

OWF_API_CALL void

OWF_Pool_Destroy(OWF_POOL* pool)

{

    if (pool)

    {

        xfree(pool->entries);

        xfree(pool->chunk);

        memset(pool, 0, sizeof(OWF_POOL));

        xfree(pool);

    }

}

#ifdef __cplusplus

}

#endif