private static byte[] GetZipCentralDirectory(DataSource apk, ApkUtils.ZipSections apkSections)
{
long cdSizeBytes = apkSections.CentralDirectorySizeBytes;
if (cdSizeBytes > int.MaxValue)
{
throw new ApkFormatException("ZIP Central Directory too large: " + cdSizeBytes);
}
long cdOffset = apkSections.CentralDirectoryOffset;
return(apk.GetByteBuffer(cdOffset, cdSizeBytes));
}
private static List <CentralDirectoryRecord> ParseZipCentralDirectory(byte[] cd, ApkUtils.ZipSections apkSections)
{
long cdOffset = apkSections.CentralDirectoryOffset;
int expectedCdRecordCount = apkSections.CentralDirectoryRecordCount;
var cdRecords = new List <CentralDirectoryRecord>(expectedCdRecordCount);
var entryNames = new HashSet <string>();
using (var ms = new DataSource(new MemoryStream(cd)))
{
for (var i = 0; i < expectedCdRecordCount; i++)
{
CentralDirectoryRecord cdRecord;
try
{
cdRecord = CentralDirectoryRecord.GetRecord(ms);
}
catch (ZipFormatException e)
{
throw new ApkFormatException(
"Malformed ZIP Central Directory record #" + (i + 1),
e);
}
var entryName = cdRecord.Name;
if (!entryNames.Add(entryName))
{
throw new ApkFormatException(
"Multiple ZIP entries with the same name: " + entryName);
}
cdRecords.Add(cdRecord);
}
if (ms.Remaining > 0)
{
throw new ApkFormatException(
"Unused space at the end of ZIP Central Directory: " + ms.Remaining
+ " bytes starting at file offset " +
(cdOffset + ms.Position));
}
}
return(cdRecords);
}
