initial commit
This commit is contained in:
i2p
Executable
+249
@@ -0,0 +1,249 @@
|
||||
#include "base64.h"
|
||||
|
||||
#include <algorithm>
|
||||
#include <stdexcept>
|
||||
|
||||
//
|
||||
// Depending on the url parameter in base64_chars, one of
|
||||
// two sets of base64 characters needs to be chosen.
|
||||
// They differ in their last two characters.
|
||||
//
|
||||
static const char* base64_chars[2] = {
|
||||
"ABCDEFGHIJKLMNOPQRSTUVWXYZ"
|
||||
"abcdefghijklmnopqrstuvwxyz"
|
||||
"0123456789"
|
||||
"+/",
|
||||
|
||||
"ABCDEFGHIJKLMNOPQRSTUVWXYZ"
|
||||
"abcdefghijklmnopqrstuvwxyz"
|
||||
"0123456789"
|
||||
"-_" };
|
||||
|
||||
static unsigned int pos_of_char(const unsigned char chr) {
|
||||
//
|
||||
// Return the position of chr within base64_encode()
|
||||
//
|
||||
|
||||
if (chr >= 'A' && chr <= 'Z') return chr - 'A';
|
||||
else if (chr >= 'a' && chr <= 'z') return chr - 'a' + ('Z' - 'A') + 1;
|
||||
else if (chr >= '0' && chr <= '9') return chr - '0' + ('Z' - 'A') + ('z' - 'a') + 2;
|
||||
else if (chr == '+' || chr == '-') return 62; // Be liberal with input and accept both url ('-') and non-url ('+') base 64 characters (
|
||||
else if (chr == '/' || chr == '_') return 63; // Ditto for '/' and '_'
|
||||
else
|
||||
//
|
||||
// 2020-10-23: Throw std::exception rather than const char*
|
||||
//(Pablo Martin-Gomez, https://github.com/Bouska)
|
||||
//
|
||||
throw std::runtime_error("Input is not valid base64-encoded data.");
|
||||
}
|
||||
|
||||
static std::string insert_linebreaks(std::string str, size_t distance) {
|
||||
//
|
||||
// Provided by https://github.com/JomaCorpFX, adapted by me.
|
||||
//
|
||||
if (!str.length()) {
|
||||
return "";
|
||||
}
|
||||
|
||||
size_t pos = distance;
|
||||
|
||||
while (pos < str.size()) {
|
||||
str.insert(pos, "\n");
|
||||
pos += distance + 1;
|
||||
}
|
||||
|
||||
return str;
|
||||
}
|
||||
|
||||
template <typename String, unsigned int line_length>
|
||||
static std::string encode_with_line_breaks(String s) {
|
||||
return insert_linebreaks(base64_encode(s, false), line_length);
|
||||
}
|
||||
|
||||
template <typename String>
|
||||
static std::string encode_pem(String s) {
|
||||
return encode_with_line_breaks<String, 64>(s);
|
||||
}
|
||||
|
||||
template <typename String>
|
||||
static std::string encode_mime(String s) {
|
||||
return encode_with_line_breaks<String, 76>(s);
|
||||
}
|
||||
|
||||
template <typename String>
|
||||
static std::string encode(String s, bool url) {
|
||||
return base64_encode(reinterpret_cast<const unsigned char*>(s.data()), s.length(), url);
|
||||
}
|
||||
|
||||
std::string base64_encode(unsigned char const* bytes_to_encode, size_t in_len, bool url) {
|
||||
|
||||
size_t len_encoded = (in_len + 2) / 3 * 4;
|
||||
|
||||
unsigned char trailing_char = url ? '.' : '=';
|
||||
|
||||
//
|
||||
// Choose set of base64 characters. They differ
|
||||
// for the last two positions, depending on the url
|
||||
// parameter.
|
||||
// A bool (as is the parameter url) is guaranteed
|
||||
// to evaluate to either 0 or 1 in C++ therefore,
|
||||
// the correct character set is chosen by subscripting
|
||||
// base64_chars with url.
|
||||
//
|
||||
const char* base64_chars_ = base64_chars[url];
|
||||
|
||||
std::string ret;
|
||||
ret.reserve(len_encoded);
|
||||
|
||||
unsigned int pos = 0;
|
||||
|
||||
while (pos < in_len) {
|
||||
ret.push_back(base64_chars_[(bytes_to_encode[pos + 0] & 0xfc) >> 2]);
|
||||
|
||||
if (pos + 1 < in_len) {
|
||||
ret.push_back(base64_chars_[((bytes_to_encode[pos + 0] & 0x03) << 4) + ((bytes_to_encode[pos + 1] & 0xf0) >> 4)]);
|
||||
|
||||
if (pos + 2 < in_len) {
|
||||
ret.push_back(base64_chars_[((bytes_to_encode[pos + 1] & 0x0f) << 2) + ((bytes_to_encode[pos + 2] & 0xc0) >> 6)]);
|
||||
ret.push_back(base64_chars_[bytes_to_encode[pos + 2] & 0x3f]);
|
||||
}
|
||||
else {
|
||||
ret.push_back(base64_chars_[(bytes_to_encode[pos + 1] & 0x0f) << 2]);
|
||||
ret.push_back(trailing_char);
|
||||
}
|
||||
}
|
||||
else {
|
||||
|
||||
ret.push_back(base64_chars_[(bytes_to_encode[pos + 0] & 0x03) << 4]);
|
||||
ret.push_back(trailing_char);
|
||||
ret.push_back(trailing_char);
|
||||
}
|
||||
|
||||
pos += 3;
|
||||
}
|
||||
|
||||
|
||||
return ret;
|
||||
}
|
||||
|
||||
template <typename String>
|
||||
static std::string decode(String const& encoded_string, bool remove_linebreaks) {
|
||||
//
|
||||
// decode(…) is templated so that it can be used with String = const std::string&
|
||||
// or std::string_view (requires at least C++17)
|
||||
//
|
||||
|
||||
if (encoded_string.empty()) return std::string();
|
||||
|
||||
if (remove_linebreaks) {
|
||||
|
||||
std::string copy(encoded_string);
|
||||
|
||||
copy.erase(std::remove(copy.begin(), copy.end(), '\n'), copy.end());
|
||||
|
||||
return base64_decode(copy, false);
|
||||
}
|
||||
|
||||
size_t length_of_string = encoded_string.length();
|
||||
size_t pos = 0;
|
||||
|
||||
//
|
||||
// The approximate length (bytes) of the decoded string might be one or
|
||||
// two bytes smaller, depending on the amount of trailing equal signs
|
||||
// in the encoded string. This approximation is needed to reserve
|
||||
// enough space in the string to be returned.
|
||||
//
|
||||
size_t approx_length_of_decoded_string = length_of_string / 4 * 3;
|
||||
std::string ret;
|
||||
ret.reserve(approx_length_of_decoded_string);
|
||||
|
||||
while (pos < length_of_string) {
|
||||
//
|
||||
// Iterate over encoded input string in chunks. The size of all
|
||||
// chunks except the last one is 4 bytes.
|
||||
//
|
||||
// The last chunk might be padded with equal signs or dots
|
||||
// in order to make it 4 bytes in size as well, but this
|
||||
// is not required as per RFC 2045.
|
||||
//
|
||||
// All chunks except the last one produce three output bytes.
|
||||
//
|
||||
// The last chunk produces at least one and up to three bytes.
|
||||
//
|
||||
|
||||
size_t pos_of_char_1 = pos_of_char(encoded_string.at(pos + 1));
|
||||
|
||||
//
|
||||
// Emit the first output byte that is produced in each chunk:
|
||||
//
|
||||
ret.push_back(static_cast<std::string::value_type>(((pos_of_char(encoded_string.at(pos + 0))) << 2) + ((pos_of_char_1 & 0x30) >> 4)));
|
||||
|
||||
if ((pos + 2 < length_of_string) && // Check for data that is not padded with equal signs (which is allowed by RFC 2045)
|
||||
encoded_string.at(pos + 2) != '=' &&
|
||||
encoded_string.at(pos + 2) != '.' // accept URL-safe base 64 strings, too, so check for '.' also.
|
||||
)
|
||||
{
|
||||
//
|
||||
// Emit a chunk's second byte (which might not be produced in the last chunk).
|
||||
//
|
||||
unsigned int pos_of_char_2 = pos_of_char(encoded_string.at(pos + 2));
|
||||
ret.push_back(static_cast<std::string::value_type>(((pos_of_char_1 & 0x0f) << 4) + ((pos_of_char_2 & 0x3c) >> 2)));
|
||||
|
||||
if ((pos + 3 < length_of_string) &&
|
||||
encoded_string.at(pos + 3) != '=' &&
|
||||
encoded_string.at(pos + 3) != '.'
|
||||
)
|
||||
{
|
||||
//
|
||||
// Emit a chunk's third byte (which might not be produced in the last chunk).
|
||||
//
|
||||
ret.push_back(static_cast<std::string::value_type>(((pos_of_char_2 & 0x03) << 6) + pos_of_char(encoded_string.at(pos + 3))));
|
||||
}
|
||||
}
|
||||
|
||||
pos += 4;
|
||||
}
|
||||
|
||||
return ret;
|
||||
}
|
||||
|
||||
std::string base64_decode(std::string const& s, bool remove_linebreaks) {
|
||||
return decode(s, remove_linebreaks);
|
||||
}
|
||||
|
||||
std::string base64_encode(std::string const& s, bool url) {
|
||||
return encode(s, url);
|
||||
}
|
||||
|
||||
std::string base64_encode_pem(std::string const& s) {
|
||||
return encode_pem(s);
|
||||
}
|
||||
|
||||
std::string base64_encode_mime(std::string const& s) {
|
||||
return encode_mime(s);
|
||||
}
|
||||
|
||||
#if __cplusplus >= 201703L
|
||||
//
|
||||
// Interface with std::string_view rather than const std::string&
|
||||
// Requires C++17
|
||||
// Provided by Yannic Bonenberger (https://github.com/Yannic)
|
||||
//
|
||||
|
||||
std::string base64_encode(std::string_view s, bool url) {
|
||||
return encode(s, url);
|
||||
}
|
||||
|
||||
std::string base64_encode_pem(std::string_view s) {
|
||||
return encode_pem(s);
|
||||
}
|
||||
|
||||
std::string base64_encode_mime(std::string_view s) {
|
||||
return encode_mime(s);
|
||||
}
|
||||
|
||||
std::string base64_decode(std::string_view s, bool remove_linebreaks) {
|
||||
return decode(s, remove_linebreaks);
|
||||
}
|
||||
|
||||
#endif // __cplusplus >= 201703L
|
||||
Reference in New Issue
Block a user