ICSharpCode.SharpZipLib.Zip.ZipExtraData.ReadCheck C# (CSharp) Method

        private void ReadCheck(int length) {
            if ((_readValueStart>_data.Length)||
                (_readValueStart<4)) {
                throw new ZipException("Find must be called before calling a Read method");
            }

            if (_index>_readValueStart+_readValueLength-length) {
                throw new ZipException("End of extra data");
            }

            if (_index+length<4) {
                throw new ZipException("Cannot read before start of tag");
            }
        }