bsnes/snespurify/nall/bps/metadata.hpp

122 lines
2.7 KiB
C++
Executable File

#ifndef NALL_BPS_METADATA_HPP
#define NALL_BPS_METADATA_HPP
#include <nall/crc32.hpp>
#include <nall/file.hpp>
#include <nall/filemap.hpp>
#include <nall/stdint.hpp>
#include <nall/string.hpp>
namespace nall {
struct bpsmetadata {
inline bool load(const string &filename);
inline bool save(const string &filename, const string &metadata);
inline string metadata() const;
protected:
file sourceFile;
string metadataString;
};
bool bpsmetadata::load(const string &filename) {
if(sourceFile.open(filename, file::mode::read) == false) return false;
auto read = [&]() -> uint8_t {
return sourceFile.read();
};
auto decode = [&]() -> uint64_t {
uint64_t data = 0, shift = 1;
while(true) {
uint8_t x = read();
data += (x & 0x7f) * shift;
if(x & 0x80) break;
shift <<= 7;
data += shift;
}
return data;
};
if(read() != 'B') return false;
if(read() != 'P') return false;
if(read() != 'S') return false;
if(read() != '1') return false;
decode();
decode();
unsigned metadataSize = decode();
char data[metadataSize + 1];
for(unsigned n = 0; n < metadataSize; n++) data[n] = read();
data[metadataSize] = 0;
metadataString = (const char*)data;
return true;
}
bool bpsmetadata::save(const string &filename, const string &metadata) {
file targetFile;
if(targetFile.open(filename, file::mode::write) == false) return false;
if(sourceFile.open() == false) return false;
sourceFile.seek(0);
auto read = [&]() -> uint8_t {
return sourceFile.read();
};
auto decode = [&]() -> uint64_t {
uint64_t data = 0, shift = 1;
while(true) {
uint8_t x = read();
data += (x & 0x7f) * shift;
if(x & 0x80) break;
shift <<= 7;
data += shift;
}
return data;
};
uint32_t checksum = ~0;
auto write = [&](uint8_t data) {
targetFile.write(data);
checksum = crc32_adjust(checksum, data);
};
auto encode = [&](uint64_t data) {
while(true) {
uint64_t x = data & 0x7f;
data >>= 7;
if(data == 0) {
write(0x80 | x);
break;
}
write(x);
data--;
}
};
for(unsigned n = 0; n < 4; n++) write(read());
encode(decode());
encode(decode());
unsigned sourceLength = decode();
unsigned targetLength = metadata.length();
encode(targetLength);
sourceFile.seek(sourceLength, file::index::relative);
for(unsigned n = 0; n < targetLength; n++) write(metadata[n]);
unsigned length = sourceFile.size() - sourceFile.offset() - 4;
for(unsigned n = 0; n < length; n++) write(read());
uint32_t outputChecksum = ~checksum;
for(unsigned n = 0; n < 32; n += 8) write(outputChecksum >> n);
targetFile.close();
return true;
}
string bpsmetadata::metadata() const {
return metadataString;
}
}
#endif