86 lines
2.8 KiB
C++
86 lines
2.8 KiB
C++
#include "base64.h"
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/// Needed for base64_encode function
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const std::string Base64::chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
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/// Helper for base64_decode function
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inline bool Base64::is_base64(unsigned char c) {
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return (isalnum(c) || (c == '+') || (c == '/'));
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}
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/// Used to base64 encode data. Input is the plaintext as std::string, output is the encoded data as std::string.
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/// \param input Plaintext data to encode.
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/// \returns Base64 encoded data.
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std::string Base64::encode(std::string const input) {
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std::string ret;
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unsigned int in_len = input.size();
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char quad[4], triple[3];
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unsigned int i, x, n = 3;
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for (x = 0; x < in_len; x = x + 3) {
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if ((in_len - x) / 3 == 0) {
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n = (in_len - x) % 3;
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}
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for (i = 0; i < 3; i++) {
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triple[i] = '0';
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}
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for (i = 0; i < n; i++) {
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triple[i] = input[x + i];
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}
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quad[0] = chars[(triple[0] & 0xFC) >> 2]; // FC = 11111100
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quad[1] = chars[((triple[0] & 0x03) << 4) | ((triple[1] & 0xF0) >> 4)]; // 03 = 11
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quad[2] = chars[((triple[1] & 0x0F) << 2) | ((triple[2] & 0xC0) >> 6)]; // 0F = 1111, C0=11110
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quad[3] = chars[triple[2] & 0x3F]; // 3F = 111111
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if (n < 3) {
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quad[3] = '=';
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}
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if (n < 2) {
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quad[2] = '=';
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}
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for (i = 0; i < 4; i++) {
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ret += quad[i];
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}
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}
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return ret;
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} //base64_encode
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/// Used to base64 decode data. Input is the encoded data as std::string, output is the plaintext data as std::string.
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/// \param encoded_string Base64 encoded data to decode.
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/// \returns Plaintext decoded data.
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std::string Base64::decode(std::string const & encoded_string) {
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int in_len = encoded_string.size();
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int i = 0;
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int j = 0;
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int in_ = 0;
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unsigned char char_array_4[4], char_array_3[3];
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std::string ret;
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while (in_len-- && (encoded_string[in_] != '=') && is_base64(encoded_string[in_])) {
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char_array_4[i++ ] = encoded_string[in_];
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in_++;
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if (i == 4) {
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for (i = 0; i < 4; i++) {
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char_array_4[i] = chars.find(char_array_4[i]);
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}
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char_array_3[0] = (char_array_4[0] << 2) + ((char_array_4[1] & 0x30) >> 4);
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char_array_3[1] = ((char_array_4[1] & 0xf) << 4) + ((char_array_4[2] & 0x3c) >> 2);
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char_array_3[2] = ((char_array_4[2] & 0x3) << 6) + char_array_4[3];
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for (i = 0; (i < 3); i++) {
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ret += char_array_3[i];
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}
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i = 0;
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}
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}
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if (i) {
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for (j = i; j < 4; j++) {
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char_array_4[j] = 0;
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}
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for (j = 0; j < 4; j++) {
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char_array_4[j] = chars.find(char_array_4[j]);
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}
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char_array_3[0] = (char_array_4[0] << 2) + ((char_array_4[1] & 0x30) >> 4);
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char_array_3[1] = ((char_array_4[1] & 0xf) << 4) + ((char_array_4[2] & 0x3c) >> 2);
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char_array_3[2] = ((char_array_4[2] & 0x3) << 6) + char_array_4[3];
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for (j = 0; (j < i - 1); j++)
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ret += char_array_3[j];
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}
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return ret;
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}
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