bsnes/nall/encode/base64.hpp

69 lines
1.6 KiB
C++

#pragma once
namespace nall::Encode {
inline auto Base64(const void* vdata, uint size, const string& format = "MIME") -> string {
static bool initialized = false;
static char lookup[65] = {0};
if(!initialized) {
initialized = true;
for(uint n : range(26)) lookup[n + 0] = 'A' + n;
for(uint n : range(26)) lookup[n + 26] = 'a' + n;
for(uint n : range(10)) lookup[n + 52] = '0' + n;
}
if(format == "MIME") {
lookup[62] = '+';
lookup[63] = '/';
lookup[64] = '=';
} else if(format == "URI") {
lookup[62] = '-';
lookup[63] = '_';
lookup[64] = 0;
} else return "";
auto data = (const uint8_t*)vdata;
uint overflow = (3 - (size % 3)) % 3; //bytes to round to nearest multiple of 3
string result;
uint8_t buffer;
for(uint n : range(size)) {
switch(n % 3) {
case 0:
buffer = data[n] >> 2;
result.append(lookup[buffer]);
buffer = (data[n] & 3) << 4;
break;
case 1:
buffer |= data[n] >> 4;
result.append(lookup[buffer]);
buffer = (data[n] & 15) << 2;
break;
case 2:
buffer |= data[n] >> 6;
result.append(lookup[buffer]);
buffer = (data[n] & 63);
result.append(lookup[buffer]);
break;
}
}
if(overflow) result.append(lookup[buffer]);
if(lookup[64]) {
while(result.size() % 4) result.append(lookup[64]);
}
return result;
}
inline auto Base64(const vector<uint8_t>& buffer, const string& format = "MIME") -> string {
return Base64(buffer.data(), buffer.size(), format);
}
inline auto Base64(const string& text, const string& format = "MIME") -> string {
return Base64(text.data(), text.size(), format);
}
}