Base64 library borrowed from HTTPServer implementation...
Base64.cpp
- Committer:
- ansond
- Date:
- 2014-12-30
- Revision:
- 1:4920bc5699f3
- Parent:
- 0:687575a500e5
File content as of revision 1:4920bc5699f3:
/** * @file Base64.cpp * @brief Base64 encoding and decoding (DERIVED WORK) * @author David Smart, Smartware Computing, Doug Anson ARM * @version 1.0 * @see * * Copyright (c) 2014 * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. * * @note Copyright © 2013 by Smartware Computing, all rights reserved. * Individuals may use this application for evaluation or non-commercial * purposes. Within this restriction, changes may be made to this application * as long as this copyright notice is retained. The user shall make * clear that their work is a derived work, and not the original. * Users of this application and sources accept this application "as is" and * shall hold harmless Smartware Computing, for any undesired results while * using this application - whether real or imagined. * * author David Smart, Smartware Computing */ #ifndef WIN32 #include "mbed.h" #else #include "windows.h" typedef unsigned int uint32_t; #endif #include "Base64.h" static const char encoding_table[] = { 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '+', '/' }; static const int mod_table[] = {0, 2, 1}; Base64::Base64() { decoding_table = NULL; } Base64::~Base64() { if (decoding_table) free(decoding_table); } char * Base64::Encode(const char *data, size_t input_length, size_t *output_length) { *output_length = 4 * ((input_length + 2) / 3); char *encoded_data = (char *)malloc(*output_length+1); // often used for text, so add room for NULL if (encoded_data == NULL) return NULL; for (unsigned int i = 0, j = 0; i < input_length;) { uint32_t octet_a = i < input_length ? data[i++] : 0; uint32_t octet_b = i < input_length ? data[i++] : 0; uint32_t octet_c = i < input_length ? data[i++] : 0; uint32_t triple = (octet_a << 0x10) + (octet_b << 0x08) + octet_c; encoded_data[j++] = encoding_table[(triple >> 3 * 6) & 0x3F]; encoded_data[j++] = encoding_table[(triple >> 2 * 6) & 0x3F]; encoded_data[j++] = encoding_table[(triple >> 1 * 6) & 0x3F]; encoded_data[j++] = encoding_table[(triple >> 0 * 6) & 0x3F]; } for (int i = 0; i < mod_table[input_length % 3]; i++) encoded_data[*output_length - 1 - i] = '='; encoded_data[*output_length] = '\0'; // as a courtesy to text users return encoded_data; } char * Base64::Decode(const char *data, size_t input_length, size_t *output_length) { if (decoding_table == NULL) build_decoding_table(); if (input_length % 4 != 0) return NULL; *output_length = input_length / 4 * 3; if (data[input_length - 1] == '=') (*output_length)--; if (data[input_length - 2] == '=') (*output_length)--; char *decoded_data = (char *)malloc(*output_length+1); // often used for text, so add room for NULL if (decoded_data == NULL) return NULL; for (unsigned int i = 0, j = 0; i < input_length;) { uint32_t sextet_a = data[i] == '=' ? 0 & i++ : decoding_table[data[i++]]; uint32_t sextet_b = data[i] == '=' ? 0 & i++ : decoding_table[data[i++]]; uint32_t sextet_c = data[i] == '=' ? 0 & i++ : decoding_table[data[i++]]; uint32_t sextet_d = data[i] == '=' ? 0 & i++ : decoding_table[data[i++]]; uint32_t triple = (sextet_a << 3 * 6) + (sextet_b << 2 * 6) + (sextet_c << 1 * 6) + (sextet_d << 0 * 6); if (j < *output_length) decoded_data[j++] = (triple >> 2 * 8) & 0xFF; if (j < *output_length) decoded_data[j++] = (triple >> 1 * 8) & 0xFF; if (j < *output_length) decoded_data[j++] = (triple >> 0 * 8) & 0xFF; } decoded_data[*output_length] = '\0'; // as a courtesy to text users return decoded_data; } void Base64::build_decoding_table() { decoding_table = (char *)malloc(256); for (int i = 0; i < 64; i++) decoding_table[(unsigned char) encoding_table[i]] = i; }