/// <summary>
/// Read data descriptor at the end of compressed data.
/// </summary>
/// <param name="zip64">if set to <c>true</c> [zip64].</param>
/// <param name="data">The data to fill in.</param>
/// <returns>Returns the number of bytes read in the descriptor.</returns>
public void ReadDataDescriptor(bool zip64, DescriptorData data)
{
int intValue = ReadLEInt();
// In theory this may not be a descriptor according to PKZIP appnote.
// In practise its always there.
if (intValue != ZipConstants.DataDescriptorSignature) {
throw new ZipException("Data descriptor signature not found");
}
data.Crc = ReadLEInt();
if (zip64) {
data.CompressedSize = ReadLELong();
data.Size = ReadLELong();
}
else {
data.CompressedSize = ReadLEInt();
data.Size = ReadLEInt();
}
}
/// <summary>
/// Test an archive for integrity/validity
/// </summary>
/// <param name="testData">Perform low level data Crc check</param>
/// <param name="strategy">The <see cref="TestStrategy"></see> to apply.</param>
/// <param name="resultHandler">The <see cref="ZipTestResultHandler"></see> handler to call during testing.</param>
/// <returns>true if all tests pass, false otherwise</returns>
/// <exception cref="ObjectDisposedException">The object has already been closed.</exception>
public bool TestArchive(bool testData, TestStrategy strategy, ZipTestResultHandler resultHandler)
{
if (isDisposed_) {
throw new ObjectDisposedException("ZipFile");
}
TestStatus status = new TestStatus(this);
if ( resultHandler != null ) {
resultHandler(status, null);
}
HeaderTest test = testData ? (HeaderTest.Header | HeaderTest.Extract) : HeaderTest.Header;
bool testing = true;
try {
int entryIndex = 0;
while ( testing && (entryIndex < Count) ) {
if ( resultHandler != null ) {
status.SetEntry(this[entryIndex]);
status.SetOperation(TestOperation.EntryHeader);
resultHandler(status, null);
}
try {
TestLocalHeader(this[entryIndex], test);
}
catch(ZipException ex) {
status.AddError();
if ( resultHandler != null ) {
resultHandler(status,
string.Format("Exception during test - '{0}'", ex.Message));
}
if ( strategy == TestStrategy.FindFirstError ) {
testing = false;
}
}
if ( testing && testData && this[entryIndex].IsFile ) {
if ( resultHandler != null ) {
status.SetOperation(TestOperation.EntryData);
resultHandler(status, null);
}
Crc32 crc = new Crc32();
using (Stream entryStream = this.GetInputStream(this[entryIndex]))
{
byte[] buffer = new byte[4096];
long totalBytes = 0;
int bytesRead;
while ((bytesRead = entryStream.Read(buffer, 0, buffer.Length)) > 0)
{
crc.Update(buffer, 0, bytesRead);
if (resultHandler != null)
{
totalBytes += bytesRead;
status.SetBytesTested(totalBytes);
resultHandler(status, null);
}
}
}
if (this[entryIndex].Crc != crc.Value) {
status.AddError();
if ( resultHandler != null ) {
resultHandler(status, "CRC mismatch");
}
if ( strategy == TestStrategy.FindFirstError ) {
testing = false;
}
}
if (( this[entryIndex].Flags & (int)GeneralBitFlags.Descriptor) != 0 ) {
ZipHelperStream helper = new ZipHelperStream(baseStream_);
DescriptorData data = new DescriptorData();
helper.ReadDataDescriptor(this[entryIndex].LocalHeaderRequiresZip64, data);
if (this[entryIndex].Crc != data.Crc) {
status.AddError();
}
if (this[entryIndex].CompressedSize != data.CompressedSize) {
status.AddError();
}
if (this[entryIndex].Size != data.Size) {
status.AddError();
}
}
}
if ( resultHandler != null ) {
status.SetOperation(TestOperation.EntryComplete);
resultHandler(status, null);
}
entryIndex += 1;
}
if ( resultHandler != null ) {
status.SetOperation(TestOperation.MiscellaneousTests);
resultHandler(status, null);
}
// TODO: the 'Corrina Johns' test where local headers are missing from
// the central directory. They are therefore invisible to many archivers.
}
catch (Exception ex) {
status.AddError();
if ( resultHandler != null ) {
resultHandler(status, string.Format("Exception during test - '{0}'", ex.Message));
}
}
if ( resultHandler != null ) {
status.SetOperation(TestOperation.Complete);
status.SetEntry(null);
resultHandler(status, null);
}
return (status.ErrorCount == 0);
}
