/*

  * This file is part of FFmpeg.

  *

  * FFmpeg is free software; you can redistribute it and/or

  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *

  * FFmpeg 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
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public

  * License along with FFmpeg; if not, write to the Free Software

  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
 #include <stdint.h>
 #include <string.h>
 
 #include "atomic.h"
 #include "buffer_internal.h"
 #include "common.h"
 #include "mem.h"
 
 AVBufferRef *av_buffer_create(uint8_t *data, int size,
                               void (*free)(void *opaque, uint8_t *data),
                               void *opaque, int flags)
 {
     AVBufferRef *ref = NULL;
     AVBuffer    *buf = NULL;
 
     buf = av_mallocz(sizeof(*buf));
     if (!buf)
         return NULL;
 
     buf->data     = data;
     buf->size     = size;
     buf->free     = free ? free : av_buffer_default_free;
     buf->opaque   = opaque;
     buf->refcount = 1;
 
     if (flags & AV_BUFFER_FLAG_READONLY)
         buf->flags |= BUFFER_FLAG_READONLY;
 
     ref = av_mallocz(sizeof(*ref));
     if (!ref) {
         av_freep(&buf);
         return NULL;
     }
 
     ref->buffer = buf;
     ref->data   = data;
     ref->size   = size;
 
     return ref;
 }
 
 void av_buffer_default_free(void *opaque, uint8_t *data)
 {
     av_free(data);
 }
 
 AVBufferRef *av_buffer_alloc(int size)
 {
     AVBufferRef *ret = NULL;
     uint8_t    *data = NULL;
 
     data = av_malloc(size);
     if (!data)
         return NULL;
 
     ret = av_buffer_create(data, size, av_buffer_default_free, NULL, 0);
     if (!ret)
         av_freep(&data);
 
     return ret;
 }
 
 AVBufferRef *av_buffer_allocz(int size)
 {
     AVBufferRef *ret = av_buffer_alloc(size);
     if (!ret)
         return NULL;
 
     memset(ret->data, 0, size);
     return ret;
 }
 
 AVBufferRef *av_buffer_ref(AVBufferRef *buf)
 {
     AVBufferRef *ret = av_mallocz(sizeof(*ret));
 
     if (!ret)
         return NULL;
 
     *ret = *buf;
 
     avpriv_atomic_int_add_and_fetch(&buf->buffer->refcount, 1);
 
     return ret;
 }
 
 void av_buffer_unref(AVBufferRef **buf)
 {
     AVBuffer *b;
 
     if (!buf || !*buf)
         return;
     b = (*buf)->buffer;
     av_freep(buf);
 
     if (!avpriv_atomic_int_add_and_fetch(&b->refcount, -1)) {
         b->free(b->opaque, b->data);
         av_freep(&b);
     }
 }
 

 int av_buffer_release(AVBufferRef **buf, uint8_t **data)
 {
     AVBuffer *b;
     int ret = 0;
 
     if (data)
         *data = NULL;
     if (!buf || !*buf)
         return 0;
     b = (*buf)->buffer;
     av_freep(buf);
 
     if (data && avpriv_atomic_int_get(&b->refcount) > 1) {
         *data = av_memdup(b->data, b->size);
         if (!*data)
             ret = AVERROR(ENOMEM);
     }
 
     if (!avpriv_atomic_int_add_and_fetch(&b->refcount, -1)) {
         if (data && !*data) {
             ret = 0;
             *data = b->data;
         } else
             b->free(b->opaque, b->data);
         av_freep(&b);
     }
     return ret;
 }
 

 int av_buffer_is_writable(const AVBufferRef *buf)
 {
     if (buf->buffer->flags & AV_BUFFER_FLAG_READONLY)
         return 0;
 

     return avpriv_atomic_int_get(&buf->buffer->refcount) == 1;

 }
 

 void *av_buffer_get_opaque(const AVBufferRef *buf)
 {
     return buf->buffer->opaque;
 }
 

 int av_buffer_get_ref_count(const AVBufferRef *buf)
 {
     return buf->buffer->refcount;
 }
 

 int av_buffer_make_writable(AVBufferRef **pbuf)
 {
     AVBufferRef *newbuf, *buf = *pbuf;
 
     if (av_buffer_is_writable(buf))
         return 0;
 
     newbuf = av_buffer_alloc(buf->size);
     if (!newbuf)
         return AVERROR(ENOMEM);
 
     memcpy(newbuf->data, buf->data, buf->size);
     av_buffer_unref(pbuf);
     *pbuf = newbuf;
 
     return 0;
 }
 
 int av_buffer_realloc(AVBufferRef **pbuf, int size)
 {
     AVBufferRef *buf = *pbuf;
     uint8_t *tmp;
 
     if (!buf) {
         /* allocate a new buffer with av_realloc(), so it will be reallocatable
          * later */
         uint8_t *data = av_realloc(NULL, size);
         if (!data)
             return AVERROR(ENOMEM);
 
         buf = av_buffer_create(data, size, av_buffer_default_free, NULL, 0);
         if (!buf) {
             av_freep(&data);
             return AVERROR(ENOMEM);
         }
 
         buf->buffer->flags |= BUFFER_FLAG_REALLOCATABLE;
         *pbuf = buf;
 
         return 0;
     } else if (buf->size == size)
         return 0;
 
     if (!(buf->buffer->flags & BUFFER_FLAG_REALLOCATABLE) ||
         !av_buffer_is_writable(buf)) {
         /* cannot realloc, allocate a new reallocable buffer and copy data */
         AVBufferRef *new = NULL;
 
         av_buffer_realloc(&new, size);
         if (!new)
             return AVERROR(ENOMEM);
 
         memcpy(new->data, buf->data, FFMIN(size, buf->size));
 
         av_buffer_unref(pbuf);
         *pbuf = new;
         return 0;
     }
 
     tmp = av_realloc(buf->buffer->data, size);
     if (!tmp)
         return AVERROR(ENOMEM);
 
     buf->buffer->data = buf->data = tmp;
     buf->buffer->size = buf->size = size;
     return 0;
 }

 
 AVBufferPool *av_buffer_pool_init(int size, AVBufferRef* (*alloc)(int size))
 {
     AVBufferPool *pool = av_mallocz(sizeof(*pool));
     if (!pool)
         return NULL;
 
     pool->size     = size;
     pool->alloc    = alloc ? alloc : av_buffer_alloc;
 
     avpriv_atomic_int_set(&pool->refcount, 1);
 
     return pool;
 }
 
 /*
  * This function gets called when the pool has been uninited and
  * all the buffers returned to it.
  */
 static void buffer_pool_free(AVBufferPool *pool)
 {
     while (pool->pool) {
         BufferPoolEntry *buf = pool->pool;
         pool->pool = buf->next;
 
         buf->free(buf->opaque, buf->data);
         av_freep(&buf);
     }
     av_freep(&pool);
 }
 
 void av_buffer_pool_uninit(AVBufferPool **ppool)
 {
     AVBufferPool *pool;
 
     if (!ppool || !*ppool)
         return;
     pool   = *ppool;
     *ppool = NULL;
 
     if (!avpriv_atomic_int_add_and_fetch(&pool->refcount, -1))
         buffer_pool_free(pool);
 }
 
 /* remove the whole buffer list from the pool and return it */
 static BufferPoolEntry *get_pool(AVBufferPool *pool)
 {

     BufferPoolEntry *cur = *(void * volatile *)&pool->pool, *last = NULL;

     while (cur != last) {

         last = cur;

         cur = avpriv_atomic_ptr_cas((void * volatile *)&pool->pool, last, NULL);
         if (!cur)
             return NULL;

     }

 
     return cur;
 }
 
 static void add_to_pool(BufferPoolEntry *buf)
 {
     AVBufferPool *pool;
     BufferPoolEntry *cur, *end = buf;
 
     if (!buf)
         return;
     pool = buf->pool;
 
     while (end->next)
         end = end->next;
 

     while (avpriv_atomic_ptr_cas((void * volatile *)&pool->pool, NULL, buf)) {

         /* pool is not empty, retrieve it and append it to our list */
         cur = get_pool(pool);
         end->next = cur;
         while (end->next)
             end = end->next;
     }
 }
 
 static void pool_release_buffer(void *opaque, uint8_t *data)
 {
     BufferPoolEntry *buf = opaque;
     AVBufferPool *pool = buf->pool;

 
     if(CONFIG_MEMORY_POISONING)

         memset(buf->data, FF_MEMORY_POISON, pool->size);

     add_to_pool(buf);
     if (!avpriv_atomic_int_add_and_fetch(&pool->refcount, -1))
         buffer_pool_free(pool);
 }
 
 /* allocate a new buffer and override its free() callback so that
  * it is returned to the pool on free */
 static AVBufferRef *pool_alloc_buffer(AVBufferPool *pool)
 {
     BufferPoolEntry *buf;
     AVBufferRef     *ret;
 
     ret = pool->alloc(pool->size);
     if (!ret)
         return NULL;
 
     buf = av_mallocz(sizeof(*buf));
     if (!buf) {
         av_buffer_unref(&ret);
         return NULL;
     }
 
     buf->data   = ret->buffer->data;
     buf->opaque = ret->buffer->opaque;
     buf->free   = ret->buffer->free;
     buf->pool   = pool;
 
     ret->buffer->opaque = buf;
     ret->buffer->free   = pool_release_buffer;
 
     avpriv_atomic_int_add_and_fetch(&pool->refcount, 1);

     avpriv_atomic_int_add_and_fetch(&pool->nb_allocated, 1);

 
     return ret;
 }
 
 AVBufferRef *av_buffer_pool_get(AVBufferPool *pool)
 {
     AVBufferRef *ret;
     BufferPoolEntry *buf;
 
     /* check whether the pool is empty */
     buf = get_pool(pool);

     if (!buf && pool->refcount <= pool->nb_allocated) {
         av_log(NULL, AV_LOG_DEBUG, "Pool race dectected, spining to avoid overallocation and eventual OOM\n");
         while (!buf && avpriv_atomic_int_get(&pool->refcount) <= avpriv_atomic_int_get(&pool->nb_allocated))
             buf = get_pool(pool);
     }
 

     if (!buf)
         return pool_alloc_buffer(pool);
 
     /* keep the first entry, return the rest of the list to the pool */
     add_to_pool(buf->next);
     buf->next = NULL;
 
     ret = av_buffer_create(buf->data, pool->size, pool_release_buffer,
                            buf, 0);
     if (!ret) {
         add_to_pool(buf);
         return NULL;
     }
     avpriv_atomic_int_add_and_fetch(&pool->refcount, 1);
 
     return ret;
 }