grab from latest android

git-svn-id: http://skia.googlecode.com/svn/trunk@27 2bbb7eff-a529-9590-31e7-b0007b416f81

1 files changed, 120 insertions, 0 deletions

diff --git a/src/core/SkChunkAlloc.cpp b/src/core/SkChunkAlloc.cpp
new file mode 100644
index 0000000000..ae37ec0839
--- /dev/null
+++ b/src/core/SkChunkAlloc.cpp
@@ -0,0 +1,120 @@
+/* libs/corecg/SkChunkAlloc.cpp
+**
+** Copyright 2006, The Android Open Source Project
+**
+** 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 "SkChunkAlloc.h"
+
+struct SkChunkAlloc::Block {
+    Block*  fNext;
+    size_t  fFreeSize;
+    char*   fFreePtr;
+    // data[] follows
+    
+    void freeChain() {    // this can be null
+        Block* block = this;
+        while (block) {
+            Block* next = block->fNext;
+            sk_free(block);
+            block = next;
+        }
+    };
+    
+    Block* tail() {
+        Block* block = this;
+        if (block) {
+            for (;;) {
+                Block* next = block->fNext;
+                if (NULL == next) {
+                    break;
+                }
+                block = next;
+            }
+        }
+        return block;
+    }
+};
+
+SkChunkAlloc::SkChunkAlloc(size_t minSize)
+    : fBlock(NULL), fMinSize(SkAlign4(minSize)), fPool(NULL), fTotalCapacity(0)
+{
+}
+
+SkChunkAlloc::~SkChunkAlloc() {
+    this->reset();
+}
+
+void SkChunkAlloc::reset() {
+    fBlock->freeChain();
+    fBlock = NULL;
+    fPool->freeChain();
+    fPool = NULL;
+    fTotalCapacity = 0;
+}
+
+void SkChunkAlloc::reuse() {
+    if (fPool && fBlock) {
+        fPool->tail()->fNext = fBlock;
+    }
+    fPool = fBlock;
+    fBlock = NULL;
+    fTotalCapacity = 0;
+}
+
+SkChunkAlloc::Block* SkChunkAlloc::newBlock(size_t bytes, AllocFailType ftype) {
+    Block* block = fPool;
+
+    if (block && bytes <= block->fFreeSize) {
+        fPool = block->fNext;
+        return block;
+    }
+
+    size_t  size = SkMax32((int32_t)bytes, (int32_t)fMinSize);
+
+    block = (Block*)sk_malloc_flags(sizeof(Block) + size,
+                        ftype == kThrow_AllocFailType ? SK_MALLOC_THROW : 0);
+
+    if (block) {
+        //    block->fNext = fBlock;
+        block->fFreeSize = size;
+        block->fFreePtr = (char*)block + sizeof(Block);
+        
+        fTotalCapacity += size;
+    }
+    return block;
+}
+
+void* SkChunkAlloc::alloc(size_t bytes, AllocFailType ftype) {
+    bytes = SkAlign4(bytes);
+
+    Block* block = fBlock;
+
+    if (block == NULL || bytes > block->fFreeSize) {
+        block = this->newBlock(bytes, ftype);
+        if (NULL == block) {
+            return NULL;
+        }
+        block->fNext = fBlock;
+        fBlock = block;
+    }
+
+    SkASSERT(block && bytes <= block->fFreeSize);
+    void* ptr = block->fFreePtr;
+
+    block->fFreeSize -= bytes;
+    block->fFreePtr += bytes;
+    return ptr;
+}
+