minetest/src/util/base64.cpp

155 lines
4.3 KiB
C++
Raw Normal View History

2014-10-28 20:13:14 +01:00
/*
base64.cpp and base64.h
2014-10-28 20:13:14 +01:00
Copyright (C) 2004-2008 René Nyffenegger
2014-10-28 20:13:14 +01:00
This source code is provided 'as-is', without any express or implied
warranty. In no event will the author be held liable for any damages
arising from the use of this software.
2014-10-28 20:13:14 +01:00
Permission is granted to anyone to use this software for any purpose,
including commercial applications, and to alter it and redistribute it
freely, subject to the following restrictions:
2014-10-28 20:13:14 +01:00
1. The origin of this source code must not be misrepresented; you must not
claim that you wrote the original source code. If you use this source code
in a product, an acknowledgment in the product documentation would be
appreciated but is not required.
2014-10-28 20:13:14 +01:00
2. Altered source versions must be plainly marked as such, and must not be
misrepresented as being the original source code.
2014-10-28 20:13:14 +01:00
3. This notice may not be removed or altered from any source distribution.
2014-10-28 20:13:14 +01:00
René Nyffenegger rene.nyffenegger@adp-gmbh.ch
*/
#include "base64.h"
#include <iostream>
2014-10-28 20:13:14 +01:00
static const std::string base64_chars =
"ABCDEFGHIJKLMNOPQRSTUVWXYZ"
"abcdefghijklmnopqrstuvwxyz"
"0123456789+/";
static const std::string base64_chars_padding_1 = "AEIMQUYcgkosw048";
static const std::string base64_chars_padding_2 = "AQgw";
static inline bool is_base64(unsigned char c)
{
return (c >= '0' && c <= '9')
|| (c >= 'A' && c <= 'Z')
|| (c >= 'a' && c <= 'z')
|| c == '+' || c == '/';
}
2012-06-03 19:32:44 +02:00
bool base64_is_valid(std::string const& s)
{
size_t i = 0;
for (; i < s.size(); ++i)
if (!is_base64(s[i]))
break;
unsigned char padding = 3 - ((i + 3) % 4);
if ((padding == 1 && base64_chars_padding_1.find(s[i - 1]) == std::string::npos)
|| (padding == 2 && base64_chars_padding_2.find(s[i - 1]) == std::string::npos)
|| padding == 3)
return false;
int actual_padding = s.size() - i;
// omission of padding characters is allowed
if (actual_padding == 0)
return true;
// remaining characters (max. 2) may only be padding
for (; i < s.size(); ++i)
if (s[i] != '=')
return false;
// number of padding characters needs to match
return padding == actual_padding;
2012-06-03 19:32:44 +02:00
}
std::string base64_encode(unsigned char const* bytes_to_encode, unsigned int in_len) {
2014-10-28 20:13:14 +01:00
std::string ret;
int i = 0;
int j = 0;
unsigned char char_array_3[3];
unsigned char char_array_4[4];
while (in_len--) {
char_array_3[i++] = *(bytes_to_encode++);
if (i == 3) {
char_array_4[0] = (char_array_3[0] & 0xfc) >> 2;
char_array_4[1] = ((char_array_3[0] & 0x03) << 4) + ((char_array_3[1] & 0xf0) >> 4);
char_array_4[2] = ((char_array_3[1] & 0x0f) << 2) + ((char_array_3[2] & 0xc0) >> 6);
char_array_4[3] = char_array_3[2] & 0x3f;
for(i = 0; (i <4) ; i++)
ret += base64_chars[char_array_4[i]];
i = 0;
}
}
if (i)
{
for(j = i; j < 3; j++)
char_array_3[j] = '\0';
char_array_4[0] = (char_array_3[0] & 0xfc) >> 2;
char_array_4[1] = ((char_array_3[0] & 0x03) << 4) + ((char_array_3[1] & 0xf0) >> 4);
char_array_4[2] = ((char_array_3[1] & 0x0f) << 2) + ((char_array_3[2] & 0xc0) >> 6);
char_array_4[3] = char_array_3[2] & 0x3f;
for (j = 0; (j < i + 1); j++)
ret += base64_chars[char_array_4[j]];
2011-06-01 23:01:11 +02:00
// Don't pad it with =
2014-10-28 20:13:14 +01:00
/*while((i++ < 3))
ret += '=';*/
2014-10-28 20:13:14 +01:00
}
2014-10-28 20:13:14 +01:00
return ret;
}
std::string base64_decode(std::string const& encoded_string) {
2014-10-28 20:13:14 +01:00
int in_len = encoded_string.size();
int i = 0;
int j = 0;
int in_ = 0;
unsigned char char_array_4[4], char_array_3[3];
std::string ret;
while (in_len-- && ( encoded_string[in_] != '=') && is_base64(encoded_string[in_])) {
char_array_4[i++] = encoded_string[in_]; in_++;
if (i ==4) {
for (i = 0; i <4; i++)
char_array_4[i] = base64_chars.find(char_array_4[i]);
char_array_3[0] = (char_array_4[0] << 2) + ((char_array_4[1] & 0x30) >> 4);
char_array_3[1] = ((char_array_4[1] & 0xf) << 4) + ((char_array_4[2] & 0x3c) >> 2);
char_array_3[2] = ((char_array_4[2] & 0x3) << 6) + char_array_4[3];
for (i = 0; (i < 3); i++)
ret += char_array_3[i];
i = 0;
}
}
if (i) {
for (j = i; j <4; j++)
char_array_4[j] = 0;
for (j = 0; j <4; j++)
char_array_4[j] = base64_chars.find(char_array_4[j]);
char_array_3[0] = (char_array_4[0] << 2) + ((char_array_4[1] & 0x30) >> 4);
char_array_3[1] = ((char_array_4[1] & 0xf) << 4) + ((char_array_4[2] & 0x3c) >> 2);
char_array_3[2] = ((char_array_4[2] & 0x3) << 6) + char_array_4[3];
for (j = 0; (j < i - 1); j++) ret += char_array_3[j];
}
return ret;
}