//construct an instance of the class and parse list of zip entries
public TinyUnzip(Stream stream, bool needDispose = true)
{
if (!stream.CanSeek)
{
throw new Exception("Unzip - stream should be able to perform Seek operation!");
}
m_needDispose = needDispose;
m_stream = stream;
m_eocd = EOCD.ReadEOCD(m_stream);
m_stream.Seek(m_eocd.offsetToCentralDir, SeekOrigin.Begin);
m_reader = new BinaryReader(m_stream);
m_centralDirEntries = new CentralDirectory[m_eocd.centralDirsTotalNum];
m_entries = new List <Entry>(m_eocd.centralDirsTotalNum);
for (int i = 0; i < m_centralDirEntries.Length; i++)
{
m_centralDirEntries[i] = CentralDirectory.Read(m_reader);
Entry entry = new Entry(m_centralDirEntries[i].fileName,
m_centralDirEntries[i].comment,
m_centralDirEntries[i].compressedSize,
m_centralDirEntries[i].uncompressedSize,
m_centralDirEntries[i].fileLastModificationTime,
m_centralDirEntries[i].fileLastModificationDate,
m_centralDirEntries[i].crc32);
m_entries.Add(entry);
}
}
static async Task <(bool success, EOCD eocd)> GetEOCD(HttpClient httpClient, Uri url, long fileSize)
{
long fileOffset = fileSize - EndFileChunkSize;
var req = new HttpRequestMessage(HttpMethod.Get, url);
req.Headers.ConnectionClose = true;
req.Headers.Range = new RangeHeaderValue(fileOffset, fileSize);
HttpResponseMessage resp = await httpClient.SendAsync(req).ConfigureAwait(false);
if (!resp.IsSuccessStatusCode)
{
return(false, null);
}
using (var eocdStream = await resp.Content.ReadAsStreamAsync().ConfigureAwait(false)) {
using (var sr = new BinaryReader(eocdStream)) {
byte[] expected = { 0x50, 0x4b, 0x05, 0x06 };
int expectedPos = 0;
for (int i = 0; i < eocdStream.Length; i++)
{
byte b = sr.ReadByte();
if (b != expected [expectedPos])
{
expectedPos = 0;
continue;
}
if (expectedPos == expected.Length - 1)
{
// We've found the signature
var eocd = new EOCD();
eocd.Signature = 0x06054b50;
eocd.DiskNumber = sr.ReadUInt16();
eocd.CDStartDisk = sr.ReadUInt16();
eocd.TotalEntriesThisDisk = sr.ReadUInt16();
eocd.TotalEntries = sr.ReadUInt16();
eocd.CDSize = sr.ReadUInt32();
eocd.CDOffset = sr.ReadUInt32();
eocd.CommentLength = sr.ReadUInt16();
return(true, eocd);
}
expectedPos++;
if (expectedPos >= expected.Length)
{
expectedPos = 0;
}
}
}
}
return(false, null);
}
static async Task <bool> ProcessEntries(HttpClient httpClient, Uri url, EOCD eocd, Stream centralDirectory, HashSet <string> neededFiles, string destinationDirectory)
{
long foundEntries = 0;
using (var br = new BinaryReader(centralDirectory)) {
long nread = 0;
long nentries = 1;
while (nread < centralDirectory.Length && nentries <= eocd.TotalEntries)
{
(bool success, CDHeader cdh) = ReadCDHeader(br, centralDirectory.Length, ref nread);
nentries++;
if (!success)
{
Console.Error.WriteLine($"Failed to read a Central Directory file header for entry {nentries}");
return(false);
}
if (!neededFiles.Contains(cdh.FileName))
{
continue;
}
if (!await ReadEntry(httpClient, url, cdh, br, destinationDirectory))
{
return(false);
}
foundEntries++;
}
}
if (foundEntries < neededFiles.Count)
{
Console.WriteLine($"Could not find all required binaries. Found {foundEntries} out of {neededFiles.Count}");
return(false);
}
return(true);
}
static EOCD ReadEOCD(BinaryReader reader)
{
EOCD eocd = new EOCD();
eocd.signature = reader.ReadUInt32();
eocd.numberOfDisk = reader.ReadUInt16();
eocd.disk = reader.ReadUInt16();
eocd.curDiskCentralDirsNum = reader.ReadUInt16();
eocd.centralDirsTotalNum = reader.ReadUInt16();
eocd.sizeOfCentralDir = reader.ReadUInt32();
eocd.offsetToCentralDir = reader.ReadUInt32();
ushort commentLength = reader.ReadUInt16();
eocd.comment = ReadAsString(reader, commentLength);
if (eocd.signature != 0x06054b50)
{
throw new Exception("Broken signature in zip archive");
}
return(eocd);
}
