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#pragma once
namespace saw {
namespace encode {
struct Base64 {};
}
template<>
class data<schema::String, encode::Base64> {
public:
using Schema = schema::String;
private:
std::string data_;
public:
data() = default;
data(std::string data__):
data_{std::move(data__)}
{}
uint64_t size() const {
return data_.size();
}
char& at(uint64_t i){
return data_.at(i);
}
const char& at(uint64_t i) const {
return data_.at(i);
}
std::string stl_string() const {
return data_;
}
bool operator==(const data<Schema, encode::Base64>& rhs) const {
return data_ == rhs.data_;
}
};
namespace impl {
constexpr std::string_view base64_char_map = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
}
template<>
class codec<schema::String, encode::Base64> {
public:
using Schema = schema::String;
private:
bool is_base64(char a) const {
for(auto iter : impl::base64_char_map){
if(iter == a){
return true;
}
}
return false;
}
error_or<uint8_t> find_base64_char_pos(char a) const {
for(uint8_t i = 0; i < impl::base64_char_map.size(); ++i){
if(impl::base64_char_map.at(i) == a){
return i;
}
}
return make_error<err::not_found>("Didn't find base64 char");
}
public:
template<typename FromEncode>
error_or<void> encode(const data<Schema, FromEncode>& from, data<Schema,encode::Base64>& to){
std::string b64_str;
try {
uint64_t unpadded_len = (from.size() * 4u + 2u).get() / 3u;
uint64_t padded_len = (unpadded_len + 3u) & ~3u;
b64_str.resize(padded_len);
}catch(const std::exception&){
return make_error<err::out_of_memory>();
}
uint64_t j{0u}, k{0u};
std::array<uint8_t,3> s{};
for(data<schema::UInt64> i = 0u; i < from.size(); ++i){
s[j] = from.at(i.get());
++j;
if(j==3){
b64_str.at(k) = impl::base64_char_map.at((s[0u] & 0xFC) >> 2);
b64_str.at(k+1u) = impl::base64_char_map.at(((s[0u] & 0x03) << 4) | ((s[1] & 0xF0) >> 4));
b64_str.at(k+2u) = impl::base64_char_map.at(((s[1u] & 0x0F) << 2) | ((s[2] & 0xC0) >> 6));
b64_str.at(k+3u) = impl::base64_char_map.at((s[2u] & 0x3F));
j = 0u;
k+=4u;
}
}
if(j > 0){
if( j == 1u ){
s[1u] = 0u;
}
b64_str.at(k+0u) = impl::base64_char_map.at((s[0u] & 0xFC) >> 2);
b64_str.at(k+1u) = impl::base64_char_map.at(((s[0u] & 0x03)<<4) + ((s[1u]&0xF0)>>4));
if(j == 2u){
b64_str.at(k+2u) = impl::base64_char_map.at( ((s[1u]&0x0F)<<2) );
}else {
b64_str.at(k+2u) = '=';
}
b64_str.at(k+3u) = '=';
}
to = {std::move(b64_str)};
return void_t{};
}
template<typename ToDecode>
error_or<void> decode(data<Schema,encode::Base64>& from, data<Schema, ToDecode>& to){
uint64_t b64_len = from.size();
if((b64_len % 4) != 0){
return make_error<err::invalid_state>("Base64 String is not padded");
}
uint64_t j{0u};
std::array<uint8_t,3> s{};
std::array<uint8_t,4> t{};
std::string to_str;
for(uint64_t i = 0u; i < b64_len && from.at(i) != '='; ++i){
auto eo_pos = this->find_base64_char_pos(from.at(i));
if(eo_pos.is_error()){
return std::move(eo_pos.get_error());
}
t[j] = eo_pos.get_value();
++j;
if(j == 4u){
s[0u] = (t[0u] << 2) + ((t[1] & 0x30) >> 4);
s[1u] = ((t[1u] & 0x0F) << 4) + ((t[2u] & 0x3C) >> 2);
s[2u] = ((t[2u] & 0x03) << 6) + t[3u];
to_str += s[0u];
to_str += s[1u];
to_str += s[2u];
j = 0u;
}
}
if(j > 0u){
for(uint64_t i = j; i < t.size(); ++i){
t[i] = 0u;
}
s[0u] = (t[0u] << 2) + ((t[1] & 0x30) >> 4);
s[1u] = ((t[1u] & 0x0F) << 4) + ((t[2u] & 0x3c) >> 2);
s[2u] = ((t[2u] & 0x03) << 6) + t[3u];
for(uint64_t i = 0u; (i+1u) < j; ++i){
to_str += s[i];
}
}
to = {std::move(to_str)};
return make_void();
}
};
}
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