bsnes/nall/encode/base64.hpp

69 lines
1.7 KiB
C++

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