93 {
94 static const std::string base64_chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
95 "abcdefghijklmnopqrstuvwxyz"
96 "0123456789+/";
97 std::string::size_type in_len = encoded_string.size();
98 std::string::size_type i = 0;
99 std::string::size_type in_ = 0;
100 char char_array_4[4];
101 char char_array_3[3];
102 std::string ret;
103
104 while (in_len-- > 0 && (encoded_string[in_] !=
'=') &&
is_base64(encoded_string[in_])) {
105 char_array_4[i++] = encoded_string[in_];
106 in_++;
107 if (i == 4) {
108 for (i = 0; i < 4; i++) {
109 char_array_4[i] = static_cast<char>(base64_chars.find(char_array_4[i]));
110 }
111
112 char_array_3[0] = static_cast<char>((char_array_4[0] << 2) + ((char_array_4[1] & 0x30) >> 4));
113 char_array_3[1] = static_cast<char>(((char_array_4[1] & 0xf) << 4) + ((char_array_4[2] & 0x3c) >> 2));
114 char_array_3[2] = static_cast<char>(((char_array_4[2] & 0x3) << 6) + char_array_4[3]);
115
116 for (i = 0; (i < 3); i++) {
117 ret += char_array_3[i];
118 }
119 i = 0;
120 }
121 }
122
123 if (i != 0) {
124 for (std::string::size_type j = i; j < 4; j++) {
125 char_array_4[j] = 0;
126 }
127
128 for (std::string::size_type j = 0; j < 4; j++) {
129 char_array_4[j] = static_cast<char>(base64_chars.find(char_array_4[j]));
130 }
131
132 char_array_3[0] = static_cast<char>((char_array_4[0] << 2) + ((char_array_4[1] & 0x30) >> 4));
133 char_array_3[1] = static_cast<char>(((char_array_4[1] & 0xf) << 4) + ((char_array_4[2] & 0x3c) >> 2));
134 char_array_3[2] = static_cast<char>(((char_array_4[2] & 0x3) << 6) + char_array_4[3]);
135
136 for (std::string::size_type j = 0; j < i - 1; j++) {
137 ret += char_array_3[j];
138 }
139 }
140
141 return ret;
142 }
static bool is_base64(char c)