2 //*********************************************************************
3 //* Base64 - a simple base64 encoder and decoder.
5 //* Copyright (c) 1999, Bob Withers - bwit@pobox.com
7 //* This code may be freely used for any purpose, either personal
8 //* or commercial, provided the authors copyright notice remains
11 //* Enhancements by Stanley Yamane:
12 //* o reverse lookup table for the decode function
13 //* o reserve string buffer space in advance
15 //*********************************************************************
17 #include "talk/base/base64.h"
21 #include "talk/base/common.h"
27 static const char kPad = '=';
28 static const unsigned char pd = 0xFD; // Padding
29 static const unsigned char sp = 0xFE; // Whitespace
30 static const unsigned char il = 0xFF; // Illegal base64 character
32 const char Base64::Base64Table[] =
33 // 0000000000111111111122222222223333333333444444444455555555556666
34 // 0123456789012345678901234567890123456789012345678901234567890123
35 "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
37 // Decode Table gives the index of any valid base64 character in the
39 // 65 == A, 97 == a, 48 == 0, 43 == +, 47 == /
41 const unsigned char Base64::DecodeTable[] = {
42 // 0 1 2 3 4 5 6 7 8 9
43 il,il,il,il,il,il,il,il,il,sp, // 0 - 9
44 sp,sp,sp,sp,il,il,il,il,il,il, // 10 - 19
45 il,il,il,il,il,il,il,il,il,il, // 20 - 29
46 il,il,sp,il,il,il,il,il,il,il, // 30 - 39
47 il,il,il,62,il,il,il,63,52,53, // 40 - 49
48 54,55,56,57,58,59,60,61,il,il, // 50 - 59
49 il,pd,il,il,il, 0, 1, 2, 3, 4, // 60 - 69
50 5, 6, 7, 8, 9,10,11,12,13,14, // 70 - 79
51 15,16,17,18,19,20,21,22,23,24, // 80 - 89
52 25,il,il,il,il,il,il,26,27,28, // 90 - 99
53 29,30,31,32,33,34,35,36,37,38, // 100 - 109
54 39,40,41,42,43,44,45,46,47,48, // 110 - 119
55 49,50,51,il,il,il,il,il,il,il, // 120 - 129
56 il,il,il,il,il,il,il,il,il,il, // 130 - 139
57 il,il,il,il,il,il,il,il,il,il, // 140 - 149
58 il,il,il,il,il,il,il,il,il,il, // 150 - 159
59 il,il,il,il,il,il,il,il,il,il, // 160 - 169
60 il,il,il,il,il,il,il,il,il,il, // 170 - 179
61 il,il,il,il,il,il,il,il,il,il, // 180 - 189
62 il,il,il,il,il,il,il,il,il,il, // 190 - 199
63 il,il,il,il,il,il,il,il,il,il, // 200 - 209
64 il,il,il,il,il,il,il,il,il,il, // 210 - 219
65 il,il,il,il,il,il,il,il,il,il, // 220 - 229
66 il,il,il,il,il,il,il,il,il,il, // 230 - 239
67 il,il,il,il,il,il,il,il,il,il, // 240 - 249
68 il,il,il,il,il,il // 250 - 255
71 bool Base64::IsBase64Char(char ch) {
72 return (('A' <= ch) && (ch <= 'Z')) ||
73 (('a' <= ch) && (ch <= 'z')) ||
74 (('0' <= ch) && (ch <= '9')) ||
75 (ch == '+') || (ch == '/');
78 bool Base64::GetNextBase64Char(char ch, char* next_ch) {
79 if (next_ch == NULL) {
82 const char* p = strchr(Base64Table, ch);
86 *next_ch = (*p) ? *p : Base64Table[0];
90 bool Base64::IsBase64Encoded(const std::string& str) {
91 for (size_t i = 0; i < str.size(); ++i) {
92 if (!IsBase64Char(str.at(i)))
98 void Base64::EncodeFromArray(const void* data, size_t len,
99 std::string* result) {
100 ASSERT(NULL != result);
102 result->resize(((len + 2) / 3) * 4);
103 const unsigned char* byte_data = static_cast<const unsigned char*>(data);
109 c = (byte_data[i] >> 2) & 0x3f;
110 (*result)[dest_ix++] = Base64Table[c];
112 c = (byte_data[i] << 4) & 0x3f;
114 c |= (byte_data[i] >> 4) & 0x0f;
116 (*result)[dest_ix++] = Base64Table[c];
119 c = (byte_data[i] << 2) & 0x3f;
121 c |= (byte_data[i] >> 6) & 0x03;
123 (*result)[dest_ix++] = Base64Table[c];
125 (*result)[dest_ix++] = kPad;
129 c = byte_data[i] & 0x3f;
130 (*result)[dest_ix++] = Base64Table[c];
133 (*result)[dest_ix++] = kPad;
138 size_t Base64::GetNextQuantum(DecodeFlags parse_flags, bool illegal_pads,
139 const char* data, size_t len, size_t* dpos,
140 unsigned char qbuf[4], bool* padded)
142 size_t byte_len = 0, pad_len = 0, pad_start = 0;
143 for (; (byte_len < 4) && (*dpos < len); ++*dpos) {
144 qbuf[byte_len] = DecodeTable[static_cast<unsigned char>(data[*dpos])];
145 if ((il == qbuf[byte_len]) || (illegal_pads && (pd == qbuf[byte_len]))) {
146 if (parse_flags != DO_PARSE_ANY)
148 // Ignore illegal characters
149 } else if (sp == qbuf[byte_len]) {
150 if (parse_flags == DO_PARSE_STRICT)
153 } else if (pd == qbuf[byte_len]) {
155 if (parse_flags != DO_PARSE_ANY)
157 // Ignore unexpected padding
158 } else if (byte_len + pad_len >= 4) {
159 if (parse_flags != DO_PARSE_ANY)
163 if (1 == ++pad_len) {
169 if (parse_flags != DO_PARSE_ANY)
171 // Ignore pads which are followed by data
177 for (size_t i = byte_len; i < 4; ++i) {
180 if (4 == byte_len + pad_len) {
185 // Roll back illegal padding
192 bool Base64::DecodeFromArray(const char* data, size_t len, DecodeFlags flags,
193 std::string* result, size_t* data_used) {
194 return DecodeFromArrayTemplate<std::string>(
195 data, len, flags, result, data_used);
198 bool Base64::DecodeFromArray(const char* data, size_t len, DecodeFlags flags,
199 vector<char>* result, size_t* data_used) {
200 return DecodeFromArrayTemplate<vector<char> >(data, len, flags, result,
205 bool Base64::DecodeFromArrayTemplate(const char* data, size_t len,
206 DecodeFlags flags, T* result,
209 ASSERT(NULL != result);
210 ASSERT(flags <= (DO_PARSE_MASK | DO_PAD_MASK | DO_TERM_MASK));
212 const DecodeFlags parse_flags = flags & DO_PARSE_MASK;
213 const DecodeFlags pad_flags = flags & DO_PAD_MASK;
214 const DecodeFlags term_flags = flags & DO_TERM_MASK;
215 ASSERT(0 != parse_flags);
216 ASSERT(0 != pad_flags);
217 ASSERT(0 != term_flags);
220 result->reserve(len);
223 bool success = true, padded;
224 unsigned char c, qbuf[4];
226 size_t qlen = GetNextQuantum(parse_flags, (DO_PAD_NO == pad_flags),
227 data, len, &dpos, qbuf, &padded);
228 c = (qbuf[0] << 2) | ((qbuf[1] >> 4) & 0x3);
230 result->push_back(c);
231 c = ((qbuf[1] << 4) & 0xf0) | ((qbuf[2] >> 2) & 0xf);
233 result->push_back(c);
234 c = ((qbuf[2] << 6) & 0xc0) | qbuf[3];
236 result->push_back(c);
242 if ((DO_TERM_ANY != term_flags) && (0 != c)) {
243 success = false; // unused bits
245 if ((DO_PAD_YES == pad_flags) && !padded) {
246 success = false; // expected padding
251 if ((DO_TERM_BUFFER == term_flags) && (dpos != len)) {
252 success = false; // unused chars
260 } // namespace talk_base