/* 
 * Copyright (C) 2008-2011 Teluu Inc. (http://www.teluu.com)
 * Copyright (C) 2003-2008 Benny Prijono <benny@prijono.org>
 *
 * 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 
 */


#include <pj/string.h>

#define PJ_POOL_ALIGN_PTR(PTR,ALIGNMENT)    (PTR + (-(pj_ssize_t)(PTR) & (ALIGNMENT-1)))
#define PJ_IS_POWER_OF_TWO(val)             (((val)>0) && ((val) & ((val)-1))==0)
#define PJ_IS_ALIGNED(PTR, ALIGNMENT)       (!((pj_ssize_t)(PTR) & ((ALIGNMENT)-1)))

PJ_IDEF(pj_size_t) pj_pool_get_capacity( pj_pool_t *pool )
{
    return pool->capacity;
}

PJ_IDEF(pj_size_t) pj_pool_get_used_size( pj_pool_t *pool )
{
    pj_pool_block *b = pool->block_list.next;
    pj_size_t used_size = sizeof(pj_pool_t);
    while (b != &pool->block_list) {
        used_size += (b->cur - b->buf) + sizeof(pj_pool_block);
        b = b->next;
    }
    return used_size;
}

PJ_IDEF(void*) pj_pool_alloc_from_block( pj_pool_block *block, pj_size_t alignment,
                                         pj_size_t size )
{
    unsigned char *ptr;

    pj_assert(PJ_IS_POWER_OF_TWO(alignment));
    // Size should be already aligned.
    // this code was moved up to pj_pool_aligned_alloc. 
    // ...and then removed there
    //
    ///* The operation below is valid for size==0. 
    // * When size==0, the function will return the pointer to the pool
    // * memory address, but no memory will be allocated.
    // */
    //if (size & (alignment -1)) {
    //    size = (size + alignment) & ~(alignment -1);
    //}
    ptr = PJ_POOL_ALIGN_PTR(block->cur, alignment);
    if (block->cur <= ptr && /* check pointer not overflowing */
        ptr <= block->end && /* check alignment not exceeding the upper limit */
        (pj_size_t)(block->end - ptr) >= size) /* check available size */
    {
        block->cur = ptr + size;
        return ptr;
    }
    return NULL;
}

PJ_IDEF(void*) pj_pool_alloc( pj_pool_t *pool, pj_size_t size)
{
    return pj_pool_aligned_alloc(pool, 0, size);
}

PJ_IDEF(void*) pj_pool_aligned_alloc(pj_pool_t *pool, pj_size_t alignment,
                                     pj_size_t size)
{
    void *ptr;

    PJ_ASSERT_RETURN(!alignment || PJ_IS_POWER_OF_TWO(alignment), NULL);

    if (!alignment)
        alignment = pool->alignment;

#if 0
    //Rounding up is the compiler's job, not the allocator's.

    /* The operation below is valid for size==0. 
     * When size==0, the function will return the pointer to the pool
     * memory address, but no memory will be allocated.
     */
    if (size & (alignment -1)) {
        size = (size + alignment) & ~(alignment -1);
    }
    pj_assert(PJ_IS_ALIGNED(size, alignment));
#endif

    ptr = pj_pool_alloc_from_block(pool->block_list.next, 
                                   alignment, size);
    if (!ptr)
        ptr = pj_pool_allocate_find(pool, alignment, size);
    return ptr;
}


PJ_IDEF(void*) pj_pool_calloc( pj_pool_t *pool, pj_size_t count, pj_size_t size)
{
    void *buf = pj_pool_alloc( pool, size*count);
    if (buf)
        pj_bzero(buf, size * count);
    return buf;
}

PJ_IDEF(const char *) pj_pool_getobjname( const pj_pool_t *pool )
{
    return pool->obj_name;
}

PJ_IDEF(pj_pool_t*) pj_pool_create( pj_pool_factory *f, 
                                    const char *name,
                                    pj_size_t initial_size, 
                                    pj_size_t increment_size,
                                    pj_pool_callback *callback)
{
    return pj_pool_aligned_create(f, name, initial_size, increment_size, 0, callback);
}

PJ_IDEF(pj_pool_t*) pj_pool_aligned_create(pj_pool_factory *f,
                                           const char *name,
                                           pj_size_t initial_size,
                                           pj_size_t increment_size,
                                           pj_size_t alignment,
                                           pj_pool_callback *callback)
{
    return (*f->create_pool)(f, name, initial_size, increment_size, alignment, callback);
}

PJ_IDEF(void) pj_pool_release( pj_pool_t *pool )
{
#if PJ_POOL_RELEASE_WIPE_DATA
    pj_pool_block *b;

    b = pool->block_list.next;
    while (b != &pool->block_list) {
        volatile unsigned char *p = b->buf;
        while (p < b->end) *p++ = 0;
        b = b->next;
    }
#endif

    if (pool->factory->release_pool)
        (*pool->factory->release_pool)(pool->factory, pool);
}


PJ_IDEF(void) pj_pool_safe_release( pj_pool_t **ppool )
{
    pj_pool_t *pool = *ppool;
    *ppool = NULL;
    if (pool)
        pj_pool_release(pool);
}

PJ_IDEF(void) pj_pool_secure_release( pj_pool_t **ppool )
{
    pj_pool_block *b;
    pj_pool_t *pool = *ppool;
    *ppool = NULL;

    if (!pool)
        return;

    b = pool->block_list.next;
    while (b != &pool->block_list) {
        volatile unsigned char *p = b->buf;
        while (p < b->end) *p++ = 0;
        b = b->next;
    }

    pj_pool_release(pool);
}
