old-nall/beat/linear.hpp
2016-05-15 12:42:10 +02:00

148 lines
3.9 KiB
C++

#pragma once
#include <nall/file.hpp>
#include <nall/filemap.hpp>
#include <nall/stdint.hpp>
#include <nall/string.hpp>
namespace nall {
struct bpslinear {
inline auto source(const uint8_t* data, uint size) -> void;
inline auto target(const uint8_t* data, uint size) -> void;
inline auto source(const string& filename) -> bool;
inline auto target(const string& filename) -> bool;
inline auto create(const string& filename, const string& metadata = "") -> bool;
protected:
enum : uint { SourceRead, TargetRead, SourceCopy, TargetCopy };
enum : uint { Granularity = 1 };
filemap sourceFile;
const uint8_t* sourceData;
uint sourceSize;
filemap targetFile;
const uint8_t* targetData;
uint targetSize;
};
auto bpslinear::source(const uint8_t* data, uint size) -> void {
sourceData = data;
sourceSize = size;
}
auto bpslinear::target(const uint8_t* data, uint size) -> void {
targetData = data;
targetSize = size;
}
auto bpslinear::source(const string& filename) -> bool {
if(sourceFile.open(filename, filemap::mode::read) == false) return false;
source(sourceFile.data(), sourceFile.size());
return true;
}
auto bpslinear::target(const string& filename) -> bool {
if(targetFile.open(filename, filemap::mode::read) == false) return false;
target(targetFile.data(), targetFile.size());
return true;
}
auto bpslinear::create(const string& filename, const string& metadata) -> bool {
file modifyFile;
if(modifyFile.open(filename, file::mode::write) == false) return false;
Hash::CRC32 modifyChecksum;
uint targetRelativeOffset = 0, outputOffset = 0;
auto write = [&](uint8_t data) {
modifyFile.write(data);
modifyChecksum.data(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--;
}
};
uint targetReadLength = 0;
auto targetReadFlush = [&]() {
if(targetReadLength) {
encode(TargetRead | ((targetReadLength - 1) << 2));
uint offset = outputOffset - targetReadLength;
while(targetReadLength) write(targetData[offset++]), targetReadLength--;
}
};
write('B');
write('P');
write('S');
write('1');
encode(sourceSize);
encode(targetSize);
uint markupSize = metadata.length();
encode(markupSize);
for(uint n = 0; n < markupSize; n++) write(metadata[n]);
while(outputOffset < targetSize) {
uint sourceLength = 0;
for(uint n = 0; outputOffset + n < min(sourceSize, targetSize); n++) {
if(sourceData[outputOffset + n] != targetData[outputOffset + n]) break;
sourceLength++;
}
uint rleLength = 0;
for(uint n = 1; outputOffset + n < targetSize; n++) {
if(targetData[outputOffset] != targetData[outputOffset + n]) break;
rleLength++;
}
if(rleLength >= 4) {
//write byte to repeat
targetReadLength++;
outputOffset++;
targetReadFlush();
//copy starting from repetition byte
encode(TargetCopy | ((rleLength - 1) << 2));
uint relativeOffset = (outputOffset - 1) - targetRelativeOffset;
encode(relativeOffset << 1);
outputOffset += rleLength;
targetRelativeOffset = outputOffset - 1;
} else if(sourceLength >= 4) {
targetReadFlush();
encode(SourceRead | ((sourceLength - 1) << 2));
outputOffset += sourceLength;
} else {
targetReadLength += Granularity;
outputOffset += Granularity;
}
}
targetReadFlush();
uint32_t sourceChecksum = Hash::CRC32(sourceData, sourceSize).value();
for(uint n = 0; n < 32; n += 8) write(sourceChecksum >> n);
uint32_t targetChecksum = Hash::CRC32(targetData, targetSize).value();
for(uint n = 0; n < 32; n += 8) write(targetChecksum >> n);
uint32_t outputChecksum = modifyChecksum.value();
for(uint n = 0; n < 32; n += 8) write(outputChecksum >> n);
modifyFile.close();
return true;
}
}