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- /*
- base64.cpp and base64.h
- Copyright (C) 2004-2008 René Nyffenegger
- Stricter validation added by the Minetest Contributors.
- 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.
- 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:
- 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.
- 2. Altered source versions must be plainly marked as such, and must not be
- misrepresented as being the original source code.
- 3. This notice may not be removed or altered from any source distribution.
- René Nyffenegger rene.nyffenegger@adp-gmbh.ch
- */
- #include "base64.h"
- #include <iostream>
- 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 == '/';
- }
- bool base64_is_valid(std::string_view 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]) == s.npos)
- || (padding == 2 && base64_chars_padding_2.find(s[i - 1]) == s.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;
- }
- std::string base64_encode(std::string_view s)
- {
- const unsigned char *bytes_to_encode = reinterpret_cast<const unsigned char*>(s.data());
- size_t in_len = s.size();
- std::string ret;
- ret.reserve(in_len + in_len / 3);
- 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]];
- // Don't pad it with =
- /*while((i++ < 3))
- ret += '=';*/
- }
- return ret;
- }
- std::string base64_decode(std::string_view encoded_string)
- {
- 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;
- ret.reserve(in_len / 4 * 3);
- 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;
- }
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