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https://gitlab.freedesktop.org/gstreamer/gstreamer.git
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182 lines
4.2 KiB
C
182 lines
4.2 KiB
C
/* GStreamer
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* Copyright (C) <2009> Collabora Ltd
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* @author: Olivier Crete <olivier.crete@collabora.co.uk
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* Copyright (C) <2009> Nokia Inc
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#ifdef HAVE_CONFIG_H
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#include "config.h"
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#endif
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#include "shmalloc.h"
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#include <stdio.h>
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#include <string.h>
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#include <assert.h>
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/* This is the allocated space to hold multiple blocks */
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struct _ShmAllocSpace
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{
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/* The total size of this space */
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size_t size;
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/* chained list of the blocks contained in this space */
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ShmAllocBlock *blocks;
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};
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/* A single block of data */
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struct _ShmAllocBlock
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{
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int use_count;
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/* Pointer back to the AllocSpace where this block is */
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ShmAllocSpace *space;
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/* The offset of this block in the alloc space */
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unsigned long offset;
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/* The size of the block */
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unsigned long size;
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/* Pointer to the next block in the chain */
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ShmAllocBlock *next;
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};
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ShmAllocSpace *
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shm_alloc_space_new (size_t size)
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{
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ShmAllocSpace *self = spalloc_new (ShmAllocSpace);
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memset (self, 0, sizeof (ShmAllocSpace));
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self->size = size;
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return self;
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}
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void
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shm_alloc_space_free (ShmAllocSpace * self)
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{
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assert (self && self->blocks == NULL);
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spalloc_free (ShmAllocSpace, self);
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}
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ShmAllocBlock *
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shm_alloc_space_alloc_block (ShmAllocSpace * self, unsigned long size)
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{
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ShmAllocBlock *block;
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ShmAllocBlock *item = NULL;
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ShmAllocBlock *prev_item = NULL;
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unsigned long prev_end_offset = 0;
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for (item = self->blocks; item; item = item->next) {
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unsigned long max_size = 0;
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max_size = item->offset - prev_end_offset;
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if (max_size >= size)
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break;
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prev_end_offset = item->offset + item->size;
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prev_item = item;
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}
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/* Return NULL if there is no big enough space, otherwise, there is space
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* at the end */
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assert (prev_end_offset <= self->size);
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if (!item && self->size - prev_end_offset < size)
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return NULL;
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block = spalloc_new (ShmAllocBlock);
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memset (block, 0, sizeof (ShmAllocBlock));
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block->offset = prev_end_offset;
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block->size = size;
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block->use_count = 1;
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block->space = self;
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if (prev_item)
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prev_item->next = block;
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else
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self->blocks = block;
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block->next = item;
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return block;
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}
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unsigned long
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shm_alloc_space_alloc_block_get_offset (ShmAllocBlock * block)
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{
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return block->offset;
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}
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static void
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shm_alloc_space_free_block (ShmAllocBlock * block)
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{
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ShmAllocBlock *item = NULL;
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ShmAllocBlock *prev_item = NULL;
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ShmAllocSpace *self = block->space;
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for (item = self->blocks; item; item = item->next) {
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if (item == block) {
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if (prev_item)
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prev_item->next = item->next;
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else
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self->blocks = item->next;
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break;
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}
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prev_item = item;
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}
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spalloc_free (ShmAllocBlock, block);
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}
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ShmAllocBlock *
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shm_alloc_space_block_get (ShmAllocSpace * self, unsigned long offset)
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{
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ShmAllocBlock *block = NULL;
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for (block = self->blocks; block; block = block->next) {
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if (block->offset <= offset && (block->offset + block->size) > offset)
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return block;
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}
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return NULL;
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}
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void
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shm_alloc_space_block_inc (ShmAllocBlock * block)
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{
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block->use_count++;
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}
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void
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shm_alloc_space_block_dec (ShmAllocBlock * block)
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{
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block->use_count--;
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if (block->use_count <= 0)
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shm_alloc_space_free_block (block);
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}
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