internal PdfArray ReadArray(IPdfStreamReader streamReader, IPdf pdf)
{
var arrayInit = streamReader.Read();
if (arrayInit != '[')
{
throw new InvalidDataException("Unexpected array initializer, expected [");
}
var items = new List <PdfObject>();
streamReader.SeekToNextToken();
while (true)
{
var item = this.ReadObject(streamReader, pdf);
if (item != null)
{
items.Add(item);
}
else
{
//ignore whitespace
if (streamReader.PeekIsNextByteWhitespace())
{
streamReader.Seek(1, SeekOrigin.Current);
}
else if (streamReader.Peek() == ']')
{
//we're at the end of the array, do nothing, it gets handled below.
}
else
{
throw new InvalidDataException("Unable to parse array, invalid object.");
}
}
if (streamReader.Peek() == ']')
{
streamReader.Seek(1, SeekOrigin.Current);
streamReader.SeekToNextToken();
break;
}
}
return(items.ToArray());
}
internal PdfBinaryString ReadBinaryString(IPdfStreamReader streamReader, PdfOptions options)
{
var start = streamReader.Read();
if (start != '<')
{
throw new InvalidDataException("Invalid starting character, should be <");
}
var data = new StringBuilder();
var buffer = new byte[512];
int endIndex;
while (true)
{
//read in a buffer of data to make it fast.
var read = streamReader.Peek(buffer, 0, buffer.Length);
var bufferText = Encoding.ASCII.GetString(buffer, 0, read);
if ((endIndex = bufferText.IndexOf(">")) >= 0)
{
if (endIndex != 0)
{
data.Append(bufferText.Substring(0, endIndex));
}
streamReader.Seek(endIndex + 1, SeekOrigin.Current);
break;
}
else
{
data.Append(bufferText);
streamReader.Seek(read + 1, SeekOrigin.Current);
}
}
streamReader.SeekToNextToken();
var result = data.ToString().GetBytesFromHexString();
return(result);
}
internal PdfDictionary ReadDictionary(IPdfStreamReader streamReader, IPdf pdf)
{
var result = new PdfDictionary();
var token = streamReader.ReadNextToken(false);
if (token != "<<")
{
throw new InvalidDataException("Unexpected dictionary start string");
}
string currentKey = null;
while (true)
{
token = streamReader.PeekNextToken();
if (token == ">>")
{
streamReader.Seek(2, SeekOrigin.Current);
streamReader.SeekToNextToken();
return(result);
}
var value = this.ReadObject(streamReader, pdf);
if (currentKey != null)
{
result.Entries[currentKey] = value;
currentKey = null;
}
else if (value is PdfName pdfName)
{
currentKey = pdfName.Value;
}
}
}
internal PdfString ReadString(IPdfStreamReader streamReader)
{
var startPosition = streamReader.Position;
var parenthesisCount = 0;
var buffer = new byte[512];
var escaped = false;
var currentCharacterCode = (string)null;
var result = string.Empty;
var totalStringBytes = 0;
var foundEndOfString = false;
var goingToNewLine = false;
while (true)
{
var bytesRead = streamReader.Read(buffer, 0, buffer.Length);
if (bytesRead <= 0)
{
throw new InvalidDataException("Unexpected end of stream");
}
for (var index = 0; index < bytesRead; index++)
{
totalStringBytes++;
var c = (char)buffer[index];
if (escaped)
{
escaped = false;
if (goingToNewLine &&
(c != '\r' &&
c != '\n'))
{
escaped = false;
goingToNewLine = false;
result += c;
continue;
}
//handled escape characters
if (c == '\r' ||
c == '\n')
{
escaped = true;
goingToNewLine = true;
}
else if (c == 'n')
{
result += '\n';
}
else if (c == 'r')
{
result += '\r';
}
else if (c == 't')
{
result += '\t';
}
else if (c == 'b')
{
result += '\b';
}
else if (c == 'f')
{
result += '\f';
}
else if (c == '(' ||
c == ')' ||
c == '\\')
{
result += c.ToString();
}
else if (c >= '0' && c <= '9')
{
if (currentCharacterCode == null)
{
currentCharacterCode = c.ToString();
escaped = true;
}
else if (currentCharacterCode.Length < 3)
{
currentCharacterCode += c.ToString();
escaped = true;
}
if (currentCharacterCode.Length == 3)
{
result += (char)Convert.ToByte(currentCharacterCode, 8);
currentCharacterCode = null;
escaped = false;
}
}
else if (currentCharacterCode != null)
{
result += $"{(char)Convert.ToByte(currentCharacterCode, 8)}{c}";
currentCharacterCode = null;
}
else
{
throw new InvalidDataException("Invalid escaped character: " + c);
}
}
else if (c == '(')
{
if (parenthesisCount > 0)
{
result += c;
}
parenthesisCount++;
}
else if (c == ')')
{
parenthesisCount--;
if (parenthesisCount > 0)
{
result += c;
}
else
{
foundEndOfString = true;
break;
}
}
else if (c == '\\')
{
escaped = true;
}
else
{
result += c;
}
}
if (foundEndOfString)
{
break;
}
}
streamReader.Seek(startPosition + totalStringBytes, SeekOrigin.Begin);
streamReader.SeekToNextToken();
return(result);
}
internal PdfStream ReadStream(IPdfStreamReader streamReader, IPdf pdf, PdfDictionary streamDictionary)
{
PdfNumber length = null;
var lengthEntry = streamDictionary["Length"];
if (lengthEntry == null)
{
throw new InvalidDataException("Unable to get required stream length. Entry not found.");
}
if (lengthEntry is PdfNumber)
{
length = lengthEntry as PdfNumber;
}
else if (lengthEntry is PdfReference reference)
{
//oh yay, we need to go dig through the pdf content for the correct value
var referenceEntry = pdf.CrossReferenceTable.Find(reference.ObjectNumber, reference.Generation);
lengthEntry = this.PeekReadObject(streamReader, pdf, referenceEntry);
length = lengthEntry as PdfNumber;
}
if (length == null)
{
throw new InvalidDataException("Unable to get required stream length. Value not found.");
}
var buffer = new byte[length];
var firstDataBuffer = new byte[6];
streamReader.Read(firstDataBuffer, 0, 6); //the word stream
streamReader.Peek(firstDataBuffer, 0, 2); // the CR+LF or LF
int seekLength;
if (firstDataBuffer[0] == 0xD && firstDataBuffer[1] == 0xA)
{
seekLength = 2;
}
else if (firstDataBuffer[0] == 0xA)
{
seekLength = 1;
}
else
{
throw new InvalidDataException("Unexpected end of line characters, expected CR+LF or just LF");
}
streamReader.Seek(seekLength, SeekOrigin.Current);
var bytesRead = streamReader.Read(buffer, 0, buffer.Length); //read the data
if (bytesRead != buffer.Length)
{
throw new InvalidDataException("Unexpected end of file while reading the data stream");
}
streamReader.SeekToNextToken(true); //end of line at the end of the stream is ok.
var endOfStreamToken = streamReader.ReadNextToken();
if (endOfStreamToken != "endstream")
{
throw new InvalidDataException("Unexpected end of stream token, expected endstream");
}
var result = new PdfStream(streamDictionary, buffer);
return(result);
}
