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ImageDataBlock.as
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ImageDataBlock.as
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/************************************************************************
* Copyright 2012 Worlize 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.
***********************************************************************/
package com.worlize.gif.blocks
{
import com.worlize.gif.errors.FileTypeError;
import com.worlize.gif.errors.OutOfDataError;
import flash.utils.ByteArray;
import flash.utils.Endian;
import flash.utils.IDataInput;
public class ImageDataBlock implements IGIFBlockCodec
{
public var bytes:ByteArray;
public var lzwMinCodeSize:uint;
public function decode(stream:IDataInput):void {
if (stream.bytesAvailable < 1) {
throw new OutOfDataError("Out of data while reading image data block LZW minimum code size.");
}
lzwMinCodeSize = stream.readUnsignedByte();
if (lzwMinCodeSize < 2 || lzwMinCodeSize > 8) {
throw new FileTypeError("Invalid GIF Data: LZW minimum code size is out of bounds.");
}
try {
bytes = DataBlock.decodeDataBlocks(stream);
}
catch (e:OutOfDataError) {
throw new OutOfDataError("Out of data while reading image data.");
}
}
public function encode(ba:ByteArray=null):ByteArray {
if (ba === null) {
ba = new ByteArray();
ba.endian = Endian.LITTLE_ENDIAN;
}
ba.writeByte(lzwMinCodeSize);
ba.writeBytes(DataBlock.encodeDataBlocks(bytes));
return ba;
}
public function dispose():void {
if (bytes) {
bytes.clear();
bytes = null;
}
}
}
}