OLD | NEW |
1 // Copyright (c) 2012, the Dart project authors. Please see the AUTHORS file | 1 // Copyright (c) 2012, the Dart project authors. Please see the AUTHORS file |
2 // for details. All rights reserved. Use of this source code is governed by a | 2 // for details. All rights reserved. Use of this source code is governed by a |
3 // BSD-style license that can be found in the LICENSE file. | 3 // BSD-style license that can be found in the LICENSE file. |
4 | 4 |
5 part of crypto; | 5 part of crypto; |
6 | 6 |
7 abstract class _CryptoUtils { | 7 abstract class _CryptoUtils { |
8 static String bytesToHex(List<int> bytes) { | 8 static String bytesToHex(List<int> bytes) { |
9 var result = new StringBuffer(); | 9 var result = new StringBuffer(); |
10 for (var part in bytes) { | 10 for (var part in bytes) { |
11 result.write('${part < 16 ? '0' : ''}${part.toRadixString(16)}'); | 11 result.write('${part < 16 ? '0' : ''}${part.toRadixString(16)}'); |
12 } | 12 } |
13 return result.toString(); | 13 return result.toString(); |
14 } | 14 } |
15 | 15 |
16 static const int PAD = 61; // '=' | |
17 static const int CR = 13; // '\r' | |
18 static const int LF = 10; // '\n' | |
19 static const int LINE_LENGTH = 76; | |
20 | |
21 static const String _encodeTable = | |
22 "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; | |
23 | |
24 static const String _encodeTableUrlSafe = | |
25 "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_"; | |
26 | |
27 // Lookup table used for finding Base 64 alphabet index of a given byte. | |
28 // -2 : Outside Base 64 alphabet. | |
29 // -1 : '\r' or '\n' | |
30 // 0 : = (Padding character). | |
31 // >0 : Base 64 alphabet index of given byte. | |
32 static const List<int> _decodeTable = | |
33 const [ -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -1, -2, -2, -1, -2, -2, | |
34 -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, | |
35 -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, 62, -2, 62, -2, 63, | |
36 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -2, -2, -2, 0, -2, -2, | |
37 -2, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, | |
38 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -2, -2, -2, -2, 63, | |
39 -2, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, | |
40 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -2, -2, -2, -2, -2, | |
41 -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, | |
42 -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, | |
43 -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, | |
44 -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, | |
45 -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, | |
46 -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, | |
47 -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, | |
48 -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2 ]; | |
49 | |
50 static String bytesToBase64(List<int> bytes, | 16 static String bytesToBase64(List<int> bytes, |
51 [bool urlSafe = false, | 17 [bool urlSafe = false, |
52 bool addLineSeparator = false]) { | 18 bool addLineSeparator = false]) { |
53 int len = bytes.length; | 19 return BASE64.encode(bytes, |
54 if (len == 0) { | 20 urlSafe: urlSafe, |
55 return ""; | 21 addLineSeparator: addLineSeparator); |
56 } | |
57 final String lookup = urlSafe ? _encodeTableUrlSafe : _encodeTable; | |
58 // Size of 24 bit chunks. | |
59 final int remainderLength = len.remainder(3); | |
60 final int chunkLength = len - remainderLength; | |
61 // Size of base output. | |
62 int outputLen = ((len ~/ 3) * 4) + ((remainderLength > 0) ? 4 : 0); | |
63 // Add extra for line separators. | |
64 if (addLineSeparator) { | |
65 outputLen += ((outputLen - 1) ~/ LINE_LENGTH) << 1; | |
66 } | |
67 List<int> out = new List<int>(outputLen); | |
68 | |
69 // Encode 24 bit chunks. | |
70 int j = 0, i = 0, c = 0; | |
71 while (i < chunkLength) { | |
72 int x = ((bytes[i++] << 16) & 0xFFFFFF) | | |
73 ((bytes[i++] << 8) & 0xFFFFFF) | | |
74 bytes[i++]; | |
75 out[j++] = lookup.codeUnitAt(x >> 18); | |
76 out[j++] = lookup.codeUnitAt((x >> 12) & 0x3F); | |
77 out[j++] = lookup.codeUnitAt((x >> 6) & 0x3F); | |
78 out[j++] = lookup.codeUnitAt(x & 0x3f); | |
79 // Add optional line separator for each 76 char output. | |
80 if (addLineSeparator && ++c == 19 && j < outputLen - 2) { | |
81 out[j++] = CR; | |
82 out[j++] = LF; | |
83 c = 0; | |
84 } | |
85 } | |
86 | |
87 // If input length if not a multiple of 3, encode remaining bytes and | |
88 // add padding. | |
89 if (remainderLength == 1) { | |
90 int x = bytes[i]; | |
91 out[j++] = lookup.codeUnitAt(x >> 2); | |
92 out[j++] = lookup.codeUnitAt((x << 4) & 0x3F); | |
93 out[j++] = PAD; | |
94 out[j++] = PAD; | |
95 } else if (remainderLength == 2) { | |
96 int x = bytes[i]; | |
97 int y = bytes[i + 1]; | |
98 out[j++] = lookup.codeUnitAt(x >> 2); | |
99 out[j++] = lookup.codeUnitAt(((x << 4) | (y >> 4)) & 0x3F); | |
100 out[j++] = lookup.codeUnitAt((y << 2) & 0x3F); | |
101 out[j++] = PAD; | |
102 } | |
103 | |
104 return new String.fromCharCodes(out); | |
105 } | 22 } |
106 | 23 |
107 static List<int> base64StringToBytes(String input) { | 24 static List<int> base64StringToBytes(String input) { |
108 int len = input.length; | 25 return BASE64.decode(input); |
109 if (len == 0) { | |
110 return new List<int>(0); | |
111 } | |
112 | |
113 // Count '\r', '\n' and illegal characters, For illegal characters, | |
114 // throw an exception. | |
115 int extrasLen = 0; | |
116 for (int i = 0; i < len; i++) { | |
117 int c = _decodeTable[input.codeUnitAt(i)]; | |
118 if (c < 0) { | |
119 extrasLen++; | |
120 if (c == -2) { | |
121 throw new FormatException('Invalid character: ${input[i]}'); | |
122 } | |
123 } | |
124 } | |
125 | |
126 if ((len - extrasLen) % 4 != 0) { | |
127 throw new FormatException('''Size of Base 64 characters in Input | |
128 must be a multiple of 4. Input: $input'''); | |
129 } | |
130 | |
131 // Count pad characters. | |
132 int padLength = 0; | |
133 for (int i = len - 1; i >= 0; i--) { | |
134 int currentCodeUnit = input.codeUnitAt(i); | |
135 if (_decodeTable[currentCodeUnit] > 0) break; | |
136 if (currentCodeUnit == PAD) padLength++; | |
137 } | |
138 int outputLen = (((len - extrasLen) * 6) >> 3) - padLength; | |
139 List<int> out = new List<int>(outputLen); | |
140 | |
141 for (int i = 0, o = 0; o < outputLen; ) { | |
142 // Accumulate 4 valid 6 bit Base 64 characters into an int. | |
143 int x = 0; | |
144 for (int j = 4; j > 0; ) { | |
145 int c = _decodeTable[input.codeUnitAt(i++)]; | |
146 if (c >= 0) { | |
147 x = ((x << 6) & 0xFFFFFF) | c; | |
148 j--; | |
149 } | |
150 } | |
151 out[o++] = x >> 16; | |
152 if (o < outputLen) { | |
153 out[o++] = (x >> 8) & 0xFF; | |
154 if (o < outputLen) out[o++] = x & 0xFF; | |
155 } | |
156 } | |
157 return out; | |
158 } | 26 } |
159 | |
160 } | 27 } |
OLD | NEW |