#include "ZipFileAdapter.hh"

#include "FileException.hh"

#include "MappedFile.hh"

#include "ZlibInflate.hh"

namespace openmsx {

ZipFileAdapter::ZipFileAdapter(std::unique_ptr<FileBase> file_, zstring_view filename_)

	: CompressedFileAdapter(std::move(file_), filename_)

{

}

void ZipFileAdapter::decompress(FileBase& f, Decompressed& d)

{

	auto mmap = MappedFile<const uint8_t>(f.mmap(0, true));

	ZlibInflate zlib(mmap);

	if (zlib.get32LE() != 0x04034B50) {

		throw FileException("Invalid ZIP file");

	}

	// skip "version needed to extract" and "general purpose bit flag"

	zlib.skip(2 + 2);

	// compression method

	if (zlib.get16LE() != 0x0008) {

		throw FileException("Unsupported zip compression method");

	}

	// skip "last mod file time", "last mod file data",

	//      "crc32",              "compressed size"

	zlib.skip(2 + 2 + 4 + 4);

	unsigned origSize = zlib.get32LE(); // uncompressed size

	unsigned filenameLen = zlib.get16LE(); // filename length

	unsigned extraFieldLen = zlib.get16LE(); // extra field length

	d.originalName = zlib.getString(filenameLen); // original filename

	zlib.skip(extraFieldLen); // skip "extra field"

	d.buf = zlib.inflate(origSize);

}

} // namespace openmsx