software.coley.llzip.format.model.LocalFileHeader Maven / Gradle / Ivy
package software.coley.llzip.format.model;
import software.coley.llzip.format.compression.Decompressor;
import software.coley.llzip.format.read.ZipReaderStrategy;
import software.coley.llzip.util.ByteData;
import software.coley.llzip.util.lazy.LazyByteData;
import software.coley.llzip.util.lazy.LazyInt;
import software.coley.llzip.util.lazy.LazyLong;
import java.io.IOException;
import java.util.Objects;
import static software.coley.llzip.format.compression.ZipCompressions.STORED;
/**
* ZIP LocalFileHeader structure.
*
* {@code
* SIGNATURE Signature ;
* WORD VersionNeededToExtract ;
* WORD GeneralPurposeBitFlag ;
* COMPRESSION_METHOD CompressionMethod ;
* DOSTIME LastModFileTime ;
* DOSDATE LastModFileDate ;
* DWORD Crc32 ;
* DWORD CompressedSize ;
* DWORD UncompressedSize ;
* WORD FileNameLength ;
* WORD ExtraFieldLength ;
* char FileName[FileNameLength] ;
* blob ExtraField[ExtraFieldLength] ;
* blob FileData[CompressedSize] ;
* }
*
*
* @author Matt Coley
*/
public class LocalFileHeader extends AbstractZipFileHeader {
protected static final long MIN_FIXED_SIZE = 30;
private transient CentralDirectoryFileHeader linkedDirectoryFileHeader;
// LocalFileHeader spec (plus common elements between this and central file)
protected LazyByteData fileData;
// Caches
private transient LazyLong fileDataLength;
private transient ByteData data;
@Override
public void read(ByteData data, long offset) {
super.read(data, offset);
this.data = data;
versionNeededToExtract = readWord(data, 4);
generalPurposeBitFlag = readWord(data, 6);
compressionMethod = readWord(data, 8);
lastModFileTime = readWord(data, 10);
lastModFileDate = readWord(data, 12);
crc32 = readQuad(data, 14);
compressedSize = readMaskedLongQuad(data, 18);
uncompressedSize = readMaskedLongQuad(data, 22);
fileNameLength = readWord(data, 26);
extraFieldLength = readWord(data, 28);
fileName = readSlice(data, new LazyInt(() -> 30), fileNameLength);
extraField = readSlice(data, fileNameLength.add(30), extraFieldLength);
fileDataLength = new LazyLong(() -> {
long fileDataLength;
if (compressionMethod.get() == STORED) {
fileDataLength = uncompressedSize.get();
} else {
fileDataLength = compressedSize.get();
}
return fileDataLength;
});
fileData = readLongSlice(data, fileNameLength.add(extraFieldLength).add(30), fileDataLength);
}
/**
* Checks if the contents do not match those described in {@link CentralDirectoryFileHeader}.
* If this is the case you will probably want to change your ZIP reading configuration.
*
* You can override the {@link ZipReaderStrategy#postProcessLocalFileHeader(LocalFileHeader)}
* to call {@link #adoptLinkedCentralDirectoryValues()}. The implementations of {@link ZipReaderStrategy}
* are non-final, so you can extend them to add the override.
*
* @return {@code true} when the contents of this file header do not match those outlined by the associated
* {@link CentralDirectoryFileHeader}.
*/
public boolean hasDifferentValuesThanCentralDirectoryHeader() {
if (linkedDirectoryFileHeader == null) return false;
if (getVersionNeededToExtract() != linkedDirectoryFileHeader.getVersionNeededToExtract()) return true;
if (getGeneralPurposeBitFlag() != linkedDirectoryFileHeader.getGeneralPurposeBitFlag()) return true;
if (getCompressionMethod() != linkedDirectoryFileHeader.getCompressionMethod()) return true;
if (getLastModFileTime() != linkedDirectoryFileHeader.getLastModFileTime()) return true;
if (getLastModFileDate() != linkedDirectoryFileHeader.getLastModFileDate()) return true;
if (getCrc32() != linkedDirectoryFileHeader.getCrc32()) return true;
if (getCompressedSize() != linkedDirectoryFileHeader.getCompressedSize()) return true;
if (getUncompressedSize() != linkedDirectoryFileHeader.getUncompressedSize()) return true;
if (getFileNameLength() != linkedDirectoryFileHeader.getFileNameLength()) return true;
return !Objects.equals(getFileNameAsString(), linkedDirectoryFileHeader.getFileNameAsString());
}
/**
* When called before being {@link #freeze() frozen} values can be adopted from the linked
* {@link #getLinkedDirectoryFileHeader() CentralDirectoryFileHeader}.
*
* In some cases the {@link LocalFileHeader} file size may be 0, but the authoritative CEN states a non-0 value,
* which you may want to adopt.
*/
public void adoptLinkedCentralDirectoryValues() {
if (data != null && linkedDirectoryFileHeader != null) {
setVersionNeededToExtract(linkedDirectoryFileHeader.getVersionNeededToExtract());
setGeneralPurposeBitFlag(linkedDirectoryFileHeader.getGeneralPurposeBitFlag());
setCompressionMethod(linkedDirectoryFileHeader.getCompressionMethod());
setLastModFileTime(linkedDirectoryFileHeader.getLastModFileTime());
setLastModFileDate(linkedDirectoryFileHeader.getLastModFileDate());
setCrc32(linkedDirectoryFileHeader.getCrc32());
setCompressedSize(linkedDirectoryFileHeader.getCompressedSize());
setUncompressedSize(linkedDirectoryFileHeader.getUncompressedSize());
setFileNameLength(linkedDirectoryFileHeader.getFileNameLength());
fileName = readSlice(data, new LazyInt(() -> 30), fileNameLength);
extraField = readSlice(data, fileNameLength.add(30), extraFieldLength);
fileDataLength = new LazyLong(() -> {
long fileDataLength;
if (compressionMethod.get() == STORED) {
fileDataLength = uncompressedSize.get();
} else {
fileDataLength = compressedSize.get();
}
return fileDataLength;
});
fileData = readLongSlice(data, fileNameLength.add(extraFieldLength).add(30), fileDataLength);
}
}
/**
* Clears the reference to the source {@link ByteData}, preventing further modification.
*
* Prevents usage of {@link #adoptLinkedCentralDirectoryValues()}.
*/
public void freeze() {
data = null;
}
@Override
public long length() {
return MIN_FIXED_SIZE +
fileNameLength.get() +
extraFieldLength.get() +
fileDataLength.get();
}
@Override
public PartType type() {
return PartType.LOCAL_FILE_HEADER;
}
@Override
public long offset() {
return offset;
}
/**
* @param decompressor
* Decompressor implementation.
*
* @return Decompressed bytes.
*
* @throws IOException
* When the decompressor fails.
*/
public ByteData decompress(Decompressor decompressor) throws IOException {
return decompressor.decompress(this, fileData.get());
}
/**
* @return The central directory file header this file is associated with.
*/
public CentralDirectoryFileHeader getLinkedDirectoryFileHeader() {
return linkedDirectoryFileHeader;
}
/**
* @param directoryFileHeader
* The central directory file header this file is associated with.
*/
public void link(CentralDirectoryFileHeader directoryFileHeader) {
this.linkedDirectoryFileHeader = directoryFileHeader;
}
/**
* @return Compressed file contents.
*
* @see #decompress(Decompressor) Decompresses this data.
*/
public ByteData getFileData() {
return fileData.get();
}
/**
* @param fileData
* Compressed file contents.
*/
public void setFileData(ByteData fileData) {
this.fileData.set(fileData);
}
@Override
public String toString() {
return "LocalFileHeader{" +
"fileData=" + fileData +
", fileDataLength=" + fileDataLength +
", data=" + data +
", versionNeededToExtract=" + versionNeededToExtract +
", generalPurposeBitFlag=" + generalPurposeBitFlag +
", compressionMethod=" + compressionMethod +
", lastModFileTime=" + lastModFileTime +
", lastModFileDate=" + lastModFileDate +
", crc32=" + crc32 +
", compressedSize=" + compressedSize +
", uncompressedSize=" + uncompressedSize +
", fileNameLength=" + fileNameLength +
", extraFieldLength=" + extraFieldLength +
", fileName='" + getFileNameAsString() + '\'' +
", extraField='" + getExtraFieldAsString() + '\'' +
'}';
}
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
LocalFileHeader that = (LocalFileHeader) o;
if (!Objects.equals(versionNeededToExtract, that.versionNeededToExtract)) return false;
if (!Objects.equals(generalPurposeBitFlag, that.generalPurposeBitFlag)) return false;
if (!Objects.equals(compressionMethod, that.compressionMethod)) return false;
if (!Objects.equals(lastModFileTime, that.lastModFileTime)) return false;
if (!Objects.equals(lastModFileDate, that.lastModFileDate)) return false;
if (!Objects.equals(crc32, that.crc32)) return false;
if (!Objects.equals(compressedSize, that.compressedSize)) return false;
if (!Objects.equals(uncompressedSize, that.uncompressedSize)) return false;
if (!Objects.equals(fileNameLength, that.fileNameLength)) return false;
if (!Objects.equals(extraFieldLength, that.extraFieldLength)) return false;
if (!Objects.equals(fileName, that.fileName)) return false;
if (!Objects.equals(extraField, that.extraField)) return false;
if (!Objects.equals(fileDataLength, that.fileDataLength)) return false;
return Objects.equals(fileData, that.fileData);
}
@Override
public int hashCode() {
int result = 0;
result = 31 * result + (versionNeededToExtract != null ? versionNeededToExtract.hashCode() : 0);
result = 31 * result + (generalPurposeBitFlag != null ? generalPurposeBitFlag.hashCode() : 0);
result = 31 * result + (compressionMethod != null ? compressionMethod.hashCode() : 0);
result = 31 * result + (lastModFileTime != null ? lastModFileTime.hashCode() : 0);
result = 31 * result + (lastModFileDate != null ? lastModFileDate.hashCode() : 0);
result = 31 * result + (crc32 != null ? crc32.hashCode() : 0);
result = 31 * result + (compressedSize != null ? compressedSize.hashCode() : 0);
result = 31 * result + (uncompressedSize != null ? uncompressedSize.hashCode() : 0);
result = 31 * result + (fileNameLength != null ? fileNameLength.hashCode() : 0);
result = 31 * result + (extraFieldLength != null ? extraFieldLength.hashCode() : 0);
result = 31 * result + (fileName != null ? fileName.hashCode() : 0);
result = 31 * result + (extraField != null ? extraField.hashCode() : 0);
result = 31 * result + (fileDataLength != null ? fileDataLength.hashCode() : 0);
result = 31 * result + (fileData != null ? fileData.hashCode() : 0);
return result;
}
}