基于 flash AS3.0 的BASE64编码与解码类

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http://programmer.blogbus.com/logs/36436446.html

在国外网站上淘到一个很好用的AS3的BASE64类感觉写得简洁而强大。很好，赶快放上来。

调用代码：

01 import com.dynamicflash.utils.Base64;     
02 //编码和解码字符串  
03 var source:String = "Hello, world";     
04 var encoded:String = Base64.encode(source);     
05 trace(encoded);     
06 var decoded:String = Base64.decode(encoded);     
07 trace(decoded);    
08 //编码和解码ByteArray  
09 var obj:Object= {name:"Dynamic Flash",url:"http://dynamicflash.com"};  
10 var source:ByteArray = new ByteArray();  
11 source.writeObject(obj);  
12 var encoded:String = Base64.encodeByteArray(source);  
13 trace(encoded);  
14 var decoded:ByteArray = Base64.decodeToByteArray(encoded);  
15 obj = decoded.readObject();  
16 trace(obj.name + "(" + obj.url + ")");

Base64类代码：

ActionScript 3语言: 临时自用代码@代码发芽网

1. package com.dynamicflash.util{  
2. import flash.utils.ByteArray;  
3. public class Base64 {  
4. private static const BASE64_CHARS:String ="ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";  
5. public static const version:String = "1.0.0";  
6. public static function encode(data:String):String {  
7. // Convert string to ByteArray
8. var bytes:ByteArray = new ByteArray();  
9.             bytes.writeUTFBytes(data);  
10. // Return encoded ByteArray
11. return encodeByteArray(bytes);  
12.         }  
13. public static function encodeByteArray(data:ByteArray):String {  
14. // Initialise output
15. var output:String = "";  
16. // Create data and output buffers
17. var dataBuffer:Array;  
18. var outputBuffer:Array = new Array(4);  
19. // Rewind ByteArray
20.             data.position = 0;  
21. // while there are still bytes to be processed
22. while (data.bytesAvailable > 0) {  
23. // Create new data buffer and populate next 3 bytes from data
24.                 dataBuffer = new Array();  
25. for (var i:uint = 0; i < 3 && data.bytesAvailable > 0; i++) {  
26.                     dataBuffer[i] = data.readUnsignedByte();  
27.                 }  
28. // Convert to data buffer Base64 character positions and 
29. // store in output buffer
30.                 outputBuffer[0] = (dataBuffer[0] & 0xfc) >> 2;  
31.                 outputBuffer[1] = ((dataBuffer[0] & 0x03) << 4) | ((dataBuffer[1]) >> 4);  
32.                 outputBuffer[2] = ((dataBuffer[1] & 0x0f) << 2) | ((dataBuffer[2]) >> 6);  
33.                 outputBuffer[3] = dataBuffer[2] & 0x3f;  
34. // If data buffer was short (i.e not 3 characters) then set
35. // end character indexes in data buffer to index of '=' symbol.
36. // This is necessary because Base64 data is always a multiple of
37. // 4 bytes and is basses with '=' symbols.
38. for (var j:uint = dataBuffer.length; j < 3; j++) {  
39.                     outputBuffer[j + 1] = 64;  
40.                 }  
41. // Loop through output buffer and add Base64 characters to 
42. // encoded data string for each character.
43. for (var k:uint = 0; k < outputBuffer.length; k++) {  
44.                     output += BASE64_CHARS.charAt(outputBuffer[k]);  
45.                 }  
46.             }  
47. // Return encoded data
48. return output;  
49.         }  
50. public static function decode(data:String):String {  
51. // Decode data to ByteArray
52. var bytes:ByteArray = decodeToByteArray(data);  
53. // Convert to string and return
54. return bytes.readUTFBytes(bytes.length);  
55.         }  
56. public static function decodeToByteArray(data:String):ByteArray {  
57. // Initialise output ByteArray for decoded data
58. var output:ByteArray = new ByteArray();  
59. // Create data and output buffers
60. var dataBuffer:Array = new Array(4);  
61. var outputBuffer:Array = new Array(3);  
62. // While there are data bytes left to be processed
63. for (var i:uint = 0; i < data.length; i += 4) {  
64. // Populate data buffer with position of Base64 characters for
65. // next 4 bytes from encoded data
66. for (var j:uint = 0; j < 4 && i + j < data.length; j++) {  
67.                     dataBuffer[j] = BASE64_CHARS.indexOf(data.charAt(i + j));  
68.                 }  
69. // Decode data buffer back into bytes
70.                 outputBuffer[0] = (dataBuffer[0] << 2) + ((dataBuffer[1] & 0x30) >> 4);  
71.                 outputBuffer[1] = ((dataBuffer[1] & 0x0f) << 4) + ((dataBuffer[2] & 0x3c) >> 2);          
72.                 outputBuffer[2] = ((dataBuffer[2] & 0x03) << 6) + dataBuffer[3];  
73. // Add all non-padded bytes in output buffer to decoded data
74. for (var k:uint = 0; k < outputBuffer.length; k++) {  
75. if (dataBuffer[k+1] == 64) break;  
76.                     output.writeByte(outputBuffer[k]);  
77.                 }  
78.             }  
79. // Rewind decoded data ByteArray
80.             output.position = 0;  
81. // Return decoded data
82. return output;  
83.         }  
84. public function Base64() { 
85. throw new Error("Base64 class is static container only");  
86.         }  
87.     }  
88. }

 

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