Flash AS3 .doc

Flash AS3 Base64网上找到的Base64执行速度都不怎么快，原因是代码对Flash执行机制没有针对性优化。 下面给出优化过的Base64，其中inline 内联的find方法需要3的flex sdk补丁才难正常编译。package import flash.utils.ByteArray; /* * 优化Base64 * 主要优化执行方式，尽量减少调用函数和尽可能不使用循环 * 优化后提升执行速度是原来的10倍 * Directed by kiwiw3 * */ public class MyBase64 public static const version:String = 2.0.0; public static function encode(data:String):String var bytes:ByteArray = new ByteArray(); bytes.writeUTFBytes(data); return encodeByteArray(bytes); private static const BASE64_CHARARR:Vector. = new 65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,97,98,99,100,101,102,103,104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119,120,121,122,48,49,50,51,52,53,54,55,56,57,43,47,61; public static function encodeByteArray(data:ByteArray):String var output:ByteArray = new ByteArray(); var opbuf0:int;var opbuf1:int;var opbuf2:int;var opbuf3:int;var dblen:int = 0;var resultlen:uint = data.length;var position:uint = 0;var oplen:uint = 0; while (resultlen 0) if (resultlen = 3) dblen = 3;resultlen -= 3;else dblen = resultlen;resultlen = 0; opbuf0 = (dataposition & 0xfc) 2;if(dblen=1) opbuf1 = (dataposition & 0x03) 4);elseopbuf1 = 64;if(dblen=2) opbuf2 = (dataposition + 1 & 0x0f) 6);elseopbuf2 = 64;if(dblen=3) opbuf3 = dataposition + 2 & 0x3f;elseopbuf3 = 64; outputoplen= BASE64_CHARARRopbuf0; outputoplen+1= BASE64_CHARARRopbuf1; outputoplen+2= BASE64_CHARARRopbuf2;outputoplen+3= BASE64_CHARARRopbuf3; position += 3;oplen += 4; return output.readUTFBytes(oplen); public static function decode(data:String):String var bytes:ByteArray = decodeToByteArray(data); return bytes.readUTFBytes(bytes.length); public static function decodeToByteArray(_data:String):ByteArray var output:ByteArray = new ByteArray();var data:ByteArray = new ByteArray();data.writeUTFBytes(_data);var databuf0:int;var databuf1:int;var databuf2:int;var databuf3:int;var resultlen:uint = data.length;var position:uint = 0;var oplen:uint = 0; while (resultlen0) find(databuf0,dataposition);if (resultlen = 1)find(databuf1,dataposition+ 1);if (resultlen = 2)find(databuf2,dataposition+ 2);if (resultlen = 3) find(databuf3,dataposition+3); if (databuf1 != 64) outputoplen = (databuf0 4);if (databuf2 != 64) outputoplen + 1 = (databuf1 & 0x0f) 2); if (databuf3 != 64) outputoplen+ 2 = (databuf2 & 0x03) = 65 & val= 97 & val= 48 & val 0) / Create new data buffer and populate next 3 bytes from data dataBuffer = new Array(); for (var i:uint = 0; i 0; i+) dataBufferi = data.readUnsignedByte(); / Convert to data buffer Base64 character positions and / store in output buffer outputBuffer0 = (dataBuffer0 & 0xfc) 2; outputBuffer1 = (dataBuffer0 & 0x03) 4); outputBuffer2 = (dataBuffer1 & 0x0f) 6); outputBuffer3 = dataBuffer2 & 0x3f; / If data buffer was short (i.e not 3 characters) then set / end character indexes in data buffer to index of = symbol. / This is necessary because Base64 data is always a multiple of / 4 bytes and is basses with = symbols. for (var j:uint = dataBuffer.length; j 3; j+) outputBufferj + 1 = 64; / Loop through output buffer and add Base64 characters to / encoded data string for each character. for (var k:uint = 0; k outputBuffer.length; k+) output += BASE64_CHARS.charAt(outputBufferk); / Return encoded data return output; public static function decode(data:String):String / Decode data to ByteArray var bytes:ByteArray = decodeToByteArray(data); / Convert to string and return return bytes.readUTFBytes(bytes.length); public static function decodeToByteArray(data:String):ByteArray / Initialise output ByteArray for decoded data var output:ByteArray = new ByteArray(); / Create data and output buffers var dataBuffer:Array = new Array(4); var outputBuffer:Array = new Array(3); / While there are data bytes left to be processed for (var i:uint = 0; i data.length; i += 4) / Populate data buffer with position of Base64 characters for / next 4 bytes from encoded data for (var j:uint = 0; j 4 & i + j data.length; j+) dataBufferj = BASE64_CHARS.indexOf(data.charAt(i + j); / Decode data buffer back into bytes outputBuffer0 = (dataBuffer0 4); outputBuffer1 = (dataBuffer1 & 0x0f) 2); outputBuffer2 = (dataBuffer2 & 0x03) 6) + dataBuffer3; / Add all non-padded bytes in output buffer to decoded data for (var k:uint = 0; k outputBuffer.length; k+) if (dataB