public PdfRawStream Parse(IRandomAccessRead reader, PdfDictionary streamDictionary, bool isLenientParsing, IPdfObjectParser parser)
{
PdfRawStream result;
// read 'stream'; this was already tested in parseObjectsDynamically()
ReadHelper.ReadExpectedString(reader, "stream");
skipWhiteSpaces(reader);
// This needs to be streamDictionary.getItem because when we are parsing, the underlying object might still be null.
ICosNumber streamLength = GetLength(reader, streamDictionary.GetItemOrDefault(CosName.LENGTH), streamDictionary.GetName(CosName.TYPE), isLenientParsing, parser);
ValidateStreamLength(reader, isLenientParsing, streamLength);
// get output stream to copy data to
using (var stream = new MemoryStream())
using (var writer = new BinaryWriter(stream))
{
if (streamLength != null && validateStreamLength(reader, streamLength.AsLong(), reader.Length()))
{
ReadValidStream(reader, writer, streamLength);
}
else
{
ReadUntilEndStream(reader, writer);
}
result = new PdfRawStream(stream.ToArray(), streamDictionary);
}
String endStream = ReadHelper.ReadString(reader);
if (endStream.Equals("endobj") && isLenientParsing)
{
log.Warn($"stream ends with \'endobj\' instead of \'endstream\' at offset {reader.GetPosition()}");
// avoid follow-up warning about missing endobj
reader.Rewind("endobj".Length);
}
else if (endStream.Length > 9 && isLenientParsing && endStream.Substring(0, 9).Equals("endstream"))
{
log.Warn("stream ends with '" + endStream + "' instead of 'endstream' at offset " + reader.GetPosition());
// unread the "extra" bytes
reader.Rewind(OtherEncodings.StringAsLatin1Bytes(endStream.Substring(9)).Length);
}
else if (!endStream.Equals("endstream"))
{
throw new InvalidOperationException("Error reading stream, expected='endstream' actual='"
+ endStream + "' at offset " + reader.GetPosition());
}
return(result);
}
private void ReadValidStream(IRandomAccessRead reader, BinaryWriter output, ICosNumber streamLengthObj)
{
long remainBytes = streamLengthObj.AsLong();
while (remainBytes > 0)
{
int chunk = (remainBytes > STREAMCOPYBUFLEN) ? STREAMCOPYBUFLEN : (int)remainBytes;
int readBytes = reader.Read(streamCopyBuf, 0, chunk);
if (readBytes <= 0)
{
// shouldn't happen, the stream length has already been validated
throw new InvalidOperationException(
$"read error at offset {reader.GetPosition()}: expected {chunk} bytes, but read() returns {readBytes}");
}
output.Write(streamCopyBuf, 0, readBytes);
remainBytes -= readBytes;
}
}
private void ValidateStreamLength(IRandomAccessRead reader, bool isLenientParsing, ICosNumber streamLength)
{
if (streamLength != null)
{
return;
}
if (isLenientParsing)
{
log.Warn("The stream doesn't provide any stream length, using fallback readUntilEnd, at offset " +
reader.GetPosition());
}
else
{
throw new InvalidOperationException("Missing length for stream.");
}
}
