From 54b6cfa9a9e5b861a9930af873580d6dc20f773c Mon Sep 17 00:00:00 2001
From: The Android Open Source Project <initial-contribution@android.com>
Date: Tue, 21 Oct 2008 07:00:00 -0700
Subject: Initial Contribution

---
 core/java/android/webkit/ByteArrayBuilder.java | 134 +++++++++++++++++++++++++
 1 file changed, 134 insertions(+)
 create mode 100644 core/java/android/webkit/ByteArrayBuilder.java

(limited to 'core/java/android/webkit/ByteArrayBuilder.java')

diff --git a/core/java/android/webkit/ByteArrayBuilder.java b/core/java/android/webkit/ByteArrayBuilder.java
new file mode 100644
index 000000000000..16d663ce390b
--- /dev/null
+++ b/core/java/android/webkit/ByteArrayBuilder.java
@@ -0,0 +1,134 @@
+/*
+ * Copyright (C) 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.
+ */
+
+package android.webkit;
+
+import java.util.LinkedList;
+
+/** Utility class optimized for accumulating bytes, and then spitting
+    them back out.  It does not optimize for returning the result in a
+    single array, though this is supported in the API. It is fastest
+    if the retrieval can be done via iterating through chunks.
+
+    Things to add:
+      - consider dynamically increasing our min_capacity,
+        as we see mTotalSize increase
+*/
+class ByteArrayBuilder {
+
+    private static final int DEFAULT_CAPACITY = 8192;
+
+    private LinkedList<Chunk> mChunks;
+
+    /** free pool */
+    private LinkedList<Chunk> mPool;
+
+    private int mMinCapacity;
+
+    public ByteArrayBuilder() {
+        init(0);
+    }
+
+    public ByteArrayBuilder(int minCapacity) {
+        init(minCapacity);
+    }
+
+    private void init(int minCapacity) {
+        mChunks = new LinkedList<Chunk>();
+        mPool = new LinkedList<Chunk>();
+
+        if (minCapacity <= 0) {
+            minCapacity = DEFAULT_CAPACITY;
+        }
+        mMinCapacity = minCapacity;
+    }
+
+    public void append(byte[] array) {
+        append(array, 0, array.length);
+    }
+
+    public synchronized void append(byte[] array, int offset, int length) {
+        while (length > 0) {
+            Chunk c = appendChunk(length);
+            int amount = Math.min(length, c.mArray.length - c.mLength);
+            System.arraycopy(array, offset, c.mArray, c.mLength, amount);
+            c.mLength += amount;
+            length -= amount;
+            offset += amount;
+        }
+    }
+
+    /**
+     * The fastest way to retrieve the data is to iterate through the
+     * chunks.  This returns the first chunk.  Note: this pulls the
+     * chunk out of the queue.  The caller must call releaseChunk() to
+     * dispose of it.
+     */
+    public synchronized Chunk getFirstChunk() {
+        if (mChunks.isEmpty()) return null;
+        return mChunks.removeFirst();
+    }
+
+    /**
+     * recycles chunk
+     */
+    public synchronized void releaseChunk(Chunk c) {
+        c.mLength = 0;
+        mPool.addLast(c);
+    }
+
+    public boolean isEmpty() {
+        return mChunks.isEmpty();
+    }
+
+    private Chunk appendChunk(int length) {
+        if (length < mMinCapacity) {
+            length = mMinCapacity;
+        }
+
+        Chunk c;
+        if (mChunks.isEmpty()) {
+            c = obtainChunk(length);
+        } else {
+            c = mChunks.getLast();
+            if (c.mLength == c.mArray.length) {
+                c = obtainChunk(length);
+            }
+        }
+        return c;
+    }
+
+    private Chunk obtainChunk(int length) {
+        Chunk c;
+        if (mPool.isEmpty()) {
+            c = new Chunk(length);
+        } else {
+            c = mPool.removeFirst();
+        }
+        mChunks.addLast(c);
+        return c;
+    }
+
+    public static class Chunk {
+        public byte[]  mArray;
+        public int     mLength;
+
+        public Chunk(int length) {
+            mArray = new byte[length];
+            mLength = 0;
+        }
+    }
+}
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