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#pragma once
#include <string>
#include <array>
namespace jwt {
namespace alphabet {
struct base64 {
static const std::array<char, 64>& data() {
static std::array<char, 64> data = {
{'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', '+', '/'}};
return data;
};
static const std::string& fill() {
static std::string fill = "=";
return fill;
}
};
struct base64url {
static const std::array<char, 64>& data() {
static std::array<char, 64> data = {
{'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', '-', '_'}};
return data;
};
static const std::string& fill() {
static std::string fill = "%3d";
return fill;
}
};
}
class base {
public:
template<typename T>
static std::string encode(const std::string& bin) {
return encode(bin, T::data(), T::fill());
}
template<typename T>
static std::string decode(const std::string& base) {
return decode(base, T::data(), T::fill());
}
private:
static std::string encode(const std::string& bin, const std::array<char, 64>& alphabet, const std::string& fill) {
size_t size = bin.size();
std::string res;
// clear incomplete bytes
size_t fast_size = size - size % 3;
for (size_t i = 0; i < fast_size;) {
uint32_t octet_a = (unsigned char)bin[i++];
uint32_t octet_b = (unsigned char)bin[i++];
uint32_t octet_c = (unsigned char)bin[i++];
uint32_t triple = (octet_a << 0x10) + (octet_b << 0x08) + octet_c;
res += alphabet[(triple >> 3 * 6) & 0x3F];
res += alphabet[(triple >> 2 * 6) & 0x3F];
res += alphabet[(triple >> 1 * 6) & 0x3F];
res += alphabet[(triple >> 0 * 6) & 0x3F];
}
if (fast_size == size)
return res;
size_t mod = size % 3;
uint32_t octet_a = fast_size < size ? (unsigned char)bin[fast_size++] : 0;
uint32_t octet_b = fast_size < size ? (unsigned char)bin[fast_size++] : 0;
uint32_t octet_c = fast_size < size ? (unsigned char)bin[fast_size++] : 0;
uint32_t triple = (octet_a << 0x10) + (octet_b << 0x08) + octet_c;
switch (mod) {
case 1:
res += alphabet[(triple >> 3 * 6) & 0x3F];
res += alphabet[(triple >> 2 * 6) & 0x3F];
res += fill;
res += fill;
break;
case 2:
res += alphabet[(triple >> 3 * 6) & 0x3F];
res += alphabet[(triple >> 2 * 6) & 0x3F];
res += alphabet[(triple >> 1 * 6) & 0x3F];
res += fill;
break;
default:
break;
}
return res;
}
static std::string decode(const std::string& base, const std::array<char, 64>& alphabet, const std::string& fill) {
size_t size = base.size();
size_t fill_cnt = 0;
while (size > fill.size()) {
if (base.substr(size - fill.size(), fill.size()) == fill) {
fill_cnt++;
size -= fill.size();
if(fill_cnt > 2)
throw std::runtime_error("Invalid input");
}
else break;
}
if ((size + fill_cnt) % 4 != 0)
throw std::runtime_error("Invalid input");
size_t out_size = size / 4 * 3;
std::string res;
res.reserve(out_size);
auto get_sextet = [&](size_t offset) {
for (size_t i = 0; i < alphabet.size(); i++) {
if (alphabet[i] == base[offset])
return i;
}
throw std::runtime_error("Invalid input");
};
size_t fast_size = size - size % 4;
for (size_t i = 0; i < fast_size;) {
uint32_t sextet_a = get_sextet(i++);
uint32_t sextet_b = get_sextet(i++);
uint32_t sextet_c = get_sextet(i++);
uint32_t sextet_d = get_sextet(i++);
uint32_t triple = (sextet_a << 3 * 6)
+ (sextet_b << 2 * 6)
+ (sextet_c << 1 * 6)
+ (sextet_d << 0 * 6);
res += (triple >> 2 * 8) & 0xFF;
res += (triple >> 1 * 8) & 0xFF;
res += (triple >> 0 * 8) & 0xFF;
}
if (fill_cnt == 0)
return res;
uint32_t triple = (get_sextet(fast_size) << 3 * 6)
+ (get_sextet(fast_size + 1) << 2 * 6);
switch (fill_cnt) {
case 1:
triple |= (get_sextet(fast_size + 2) << 1 * 6);
res += (triple >> 2 * 8) & 0xFF;
res += (triple >> 1 * 8) & 0xFF;
break;
case 2:
res += (triple >> 2 * 8) & 0xFF;
break;
default:
break;
}
return res;
}
};
}
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