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tdlib-fork/tdutils/td/utils/base64.cpp

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//
// Copyright Aliaksei Levin (levlam@telegram.org), Arseny Smirnov (arseny30@gmail.com) 2014-2019
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//
#include "td/utils/base64.h"
#include "td/utils/common.h"
#include "td/utils/Slice.h"
#include "td/utils/Status.h"
#include <algorithm>
#include <iterator>
namespace td {
//TODO: fix copypaste
static const char *const symbols64 = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
string base64_encode(Slice input) {
string base64;
base64.reserve((input.size() + 2) / 3 * 4);
for (size_t i = 0; i < input.size();) {
size_t left = min(input.size() - i, static_cast<size_t>(3));
int c = input.ubegin()[i++] << 16;
base64 += symbols64[c >> 18];
if (left != 1) {
c |= input.ubegin()[i++] << 8;
}
base64 += symbols64[(c >> 12) & 63];
if (left == 3) {
c |= input.ubegin()[i++];
}
if (left != 1) {
base64 += symbols64[(c >> 6) & 63];
} else {
base64 += '=';
}
if (left == 3) {
base64 += symbols64[c & 63];
} else {
base64 += '=';
}
}
return base64;
}
static unsigned char char_to_value[256];
static void init_base64_table() {
static bool is_inited = [] {
std::fill(std::begin(char_to_value), std::end(char_to_value), static_cast<unsigned char>(64));
for (unsigned char i = 0; i < 64; i++) {
char_to_value[static_cast<size_t>(symbols64[i])] = i;
}
return true;
}();
CHECK(is_inited);
}
Result<Slice> base64_drop_padding(Slice base64) {
if ((base64.size() & 3) != 0) {
return Status::Error("Wrong string length");
}
size_t padding_length = 0;
while (!base64.empty() && base64.back() == '=') {
base64.remove_suffix(1);
padding_length++;
}
if (padding_length >= 3) {
return Status::Error("Wrong string padding");
}
return base64;
}
template <class F>
Status base64_do_decode(Slice base64, F &&append) {
for (size_t i = 0; i < base64.size();) {
size_t left = min(base64.size() - i, static_cast<size_t>(4));
int c = 0;
for (size_t t = 0; t < left; t++) {
auto value = char_to_value[base64.ubegin()[i++]];
if (value == 64) {
return Status::Error("Wrong character in the string");
}
c |= value << ((3 - t) * 6);
}
append(static_cast<char>(static_cast<unsigned char>(c >> 16))); // implementation-defined
if (left == 2) {
if ((c & ((1 << 16) - 1)) != 0) {
return Status::Error("Wrong padding in the string");
}
} else {
append(static_cast<char>(static_cast<unsigned char>(c >> 8))); // implementation-defined
if (left == 3) {
if ((c & ((1 << 8) - 1)) != 0) {
return Status::Error("Wrong padding in the string");
}
} else {
append(static_cast<char>(static_cast<unsigned char>(c))); // implementation-defined
}
}
}
return Status::OK();
}
Result<string> base64_decode(Slice base64) {
init_base64_table();
TRY_RESULT_ASSIGN(base64, base64_drop_padding(base64));
string output;
output.reserve(((base64.size() + 3) >> 2) * 3);
TRY_STATUS(base64_do_decode(base64, [&output](char c) { output += c; }));
return output;
}
Result<SecureString> base64_decode_secure(Slice base64) {
init_base64_table();
TRY_RESULT_ASSIGN(base64, base64_drop_padding(base64));
SecureString output(((base64.size() + 3) >> 2) * 3);
char *ptr = output.as_mutable_slice().begin();
TRY_STATUS(base64_do_decode(base64, [&ptr](char c) { *ptr++ = c; }));
size_t size = ptr - output.as_mutable_slice().begin();
if (size == output.size()) {
return std::move(output);
}
return SecureString(output.as_slice().substr(0, size));
}
static const char *const url_symbols64 = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_";
string base64url_encode(Slice input) {
string base64;
base64.reserve((input.size() + 2) / 3 * 4);
for (size_t i = 0; i < input.size();) {
size_t left = min(input.size() - i, static_cast<size_t>(3));
int c = input.ubegin()[i++] << 16;
base64 += url_symbols64[c >> 18];
if (left != 1) {
c |= input.ubegin()[i++] << 8;
}
base64 += url_symbols64[(c >> 12) & 63];
if (left == 3) {
c |= input.ubegin()[i++];
}
if (left != 1) {
base64 += url_symbols64[(c >> 6) & 63];
}
if (left == 3) {
base64 += url_symbols64[c & 63];
}
}
return base64;
}
static unsigned char url_char_to_value[256];
static void init_base64url_table() {
static bool is_inited = [] {
std::fill(std::begin(url_char_to_value), std::end(url_char_to_value), static_cast<unsigned char>(64));
for (unsigned char i = 0; i < 64; i++) {
url_char_to_value[static_cast<size_t>(url_symbols64[i])] = i;
}
return true;
}();
CHECK(is_inited);
}
Result<string> base64url_decode(Slice base64) {
init_base64url_table();
size_t padding_length = 0;
while (!base64.empty() && base64.back() == '=') {
base64.remove_suffix(1);
padding_length++;
}
if (padding_length >= 3 || (padding_length > 0 && ((base64.size() + padding_length) & 3) != 0)) {
return Status::Error("Wrong string padding");
}
if ((base64.size() & 3) == 1) {
return Status::Error("Wrong string length");
}
string output;
output.reserve(((base64.size() + 3) >> 2) * 3);
for (size_t i = 0; i < base64.size();) {
size_t left = min(base64.size() - i, static_cast<size_t>(4));
int c = 0;
for (size_t t = 0; t < left; t++) {
auto value = url_char_to_value[base64.ubegin()[i++]];
if (value == 64) {
return Status::Error("Wrong character in the string");
}
c |= value << ((3 - t) * 6);
}
output += static_cast<char>(static_cast<unsigned char>(c >> 16)); // implementation-defined
if (left == 2) {
if ((c & ((1 << 16) - 1)) != 0) {
return Status::Error("Wrong padding in the string");
}
} else {
output += static_cast<char>(static_cast<unsigned char>(c >> 8)); // implementation-defined
if (left == 3) {
if ((c & ((1 << 8) - 1)) != 0) {
return Status::Error("Wrong padding in the string");
}
} else {
output += static_cast<char>(static_cast<unsigned char>(c)); // implementation-defined
}
}
}
return output;
}
template <bool is_url>
static bool is_base64_impl(Slice input) {
size_t padding_length = 0;
while (!input.empty() && input.back() == '=') {
input.remove_suffix(1);
padding_length++;
}
if (padding_length >= 3) {
return false;
}
if ((!is_url || padding_length > 0) && ((input.size() + padding_length) & 3) != 0) {
return false;
}
if (is_url && (input.size() & 3) == 1) {
return false;
}
unsigned char *table;
if (is_url) {
init_base64url_table();
table = url_char_to_value;
} else {
init_base64_table();
table = char_to_value;
}
for (auto c : input) {
if (table[static_cast<unsigned char>(c)] == 64) {
return false;
}
}
if ((input.size() & 3) == 2) {
auto value = table[static_cast<int>(input.back())];
if ((value & 15) != 0) {
return false;
}
}
if ((input.size() & 3) == 3) {
auto value = table[static_cast<int>(input.back())];
if ((value & 3) != 0) {
return false;
}
}
return true;
}
bool is_base64(Slice input) {
return is_base64_impl<false>(input);
}
bool is_base64url(Slice input) {
return is_base64_impl<true>(input);
}
string base64_filter(Slice input) {
string res;
res.reserve(input.size());
init_base64_table();
for (auto c : input) {
if (char_to_value[static_cast<unsigned char>(c)] != 64 || c == '=') {
res += c;
}
}
return res;
}
} // namespace td