add gpu backend (not hooked up yet)
git-svn-id: http://skia.googlecode.com/svn/trunk@649 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/gpu/src/GrAllocPool.cpp b/gpu/src/GrAllocPool.cpp
new file mode 100644
index 0000000..f133f97
--- /dev/null
+++ b/gpu/src/GrAllocPool.cpp
@@ -0,0 +1,127 @@
+/*
+ Copyright 2010 Google Inc.
+
+ Licensed under the Apache License, Version 2.0 (the "License");
+ you may not use this file except in compliance with the License.
+ You may obtain a copy of the License at
+
+ http://www.apache.org/licenses/LICENSE-2.0
+
+ Unless required by applicable law or agreed to in writing, software
+ distributed under the License is distributed on an "AS IS" BASIS,
+ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ See the License for the specific language governing permissions and
+ limitations under the License.
+ */
+
+
+#include "GrAllocPool.h"
+
+#define GrAllocPool_MIN_BLOCK_SIZE ((size_t)128)
+
+struct GrAllocPool::Block {
+ Block* fNext;
+ char* fPtr;
+ size_t fBytesFree;
+ size_t fBytesTotal;
+
+ static Block* Create(size_t size, Block* next) {
+ GrAssert(size >= GrAllocPool_MIN_BLOCK_SIZE);
+
+ Block* block = (Block*)GrMalloc(sizeof(Block) + size);
+ block->fNext = next;
+ block->fPtr = (char*)block + sizeof(Block);
+ block->fBytesFree = size;
+ block->fBytesTotal = size;
+ return block;
+ }
+
+ bool canAlloc(size_t bytes) const {
+ return bytes <= fBytesFree;
+ }
+
+ void* alloc(size_t bytes) {
+ GrAssert(bytes <= fBytesFree);
+ fBytesFree -= bytes;
+ void* ptr = fPtr;
+ fPtr += bytes;
+ return ptr;
+ }
+
+ size_t release(size_t bytes) {
+ GrAssert(bytes > 0);
+ size_t free = GrMin(bytes, fBytesTotal - fBytesFree);
+ fBytesFree += free;
+ fPtr -= free;
+ return bytes - free;
+ }
+
+ bool empty() const { return fBytesTotal == fBytesFree; }
+};
+
+///////////////////////////////////////////////////////////////////////////////
+
+GrAllocPool::GrAllocPool(size_t blockSize) {
+ fBlock = NULL;
+ fMinBlockSize = GrMax(blockSize, GrAllocPool_MIN_BLOCK_SIZE);
+ GR_DEBUGCODE(fBlocksAllocated = 0;)
+}
+
+GrAllocPool::~GrAllocPool() {
+ this->reset();
+}
+
+void GrAllocPool::reset() {
+ this->validate();
+
+ Block* block = fBlock;
+ while (block) {
+ Block* next = block->fNext;
+ GrFree(block);
+ block = next;
+ }
+ fBlock = NULL;
+ GR_DEBUGCODE(fBlocksAllocated = 0;)
+}
+
+void* GrAllocPool::alloc(size_t size) {
+ this->validate();
+
+ if (!fBlock || !fBlock->canAlloc(size)) {
+ size_t blockSize = GrMax(fMinBlockSize, size);
+ fBlock = Block::Create(blockSize, fBlock);
+ GR_DEBUGCODE(fBlocksAllocated += 1;)
+ }
+ return fBlock->alloc(size);
+}
+
+void GrAllocPool::release(size_t bytes) {
+ this->validate();
+
+ while (bytes && NULL != fBlock) {
+ bytes = fBlock->release(bytes);
+ if (fBlock->empty()) {
+ Block* next = fBlock->fNext;
+ GrFree(fBlock);
+ fBlock = next;
+ GR_DEBUGCODE(fBlocksAllocated -= 1;)
+ }
+ }
+}
+
+
+#if GR_DEBUG
+
+void GrAllocPool::validate() const {
+ Block* block = fBlock;
+ int count = 0;
+ while (block) {
+ count += 1;
+ block = block->fNext;
+ }
+ GrAssert(fBlocksAllocated == count);
+}
+
+#endif
+
+