基於 flash AS3.0 的BASE64編碼與解碼類
阿新 • • 發佈:2019-02-10
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. }
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
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
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. }