private bool validateStreamLength(IRandomAccessRead source, long streamLength, long fileLength)
{
bool streamLengthIsValid = true;
long originOffset = source.GetPosition();
long expectedEndOfStream = originOffset + streamLength;
if (expectedEndOfStream > fileLength)
{
streamLengthIsValid = false;
//LOG.warn("The end of the stream is out of range, using workaround to read the stream, "
// + "stream start position: " + originOffset + ", length: " + streamLength
// + ", expected end position: " + expectedEndOfStream);
}
else
{
source.Seek(expectedEndOfStream);
ReadHelper.SkipSpaces(source);
if (!ReadHelper.IsString(source, "endstream"))
{
streamLengthIsValid = false;
//LOG.warn("The end of the stream doesn't point to the correct offset, using workaround to read the stream, "
// + "stream start position: " + originOffset + ", length: " + streamLength
// + ", expected end position: " + expectedEndOfStream);
}
source.Seek(originOffset);
}
return(streamLengthIsValid);
}
public PdfDictionary Parse(IRandomAccessRead reader, IBaseParser baseParser, CosObjectPool pool)
{
if (reader == null)
{
throw new ArgumentNullException(nameof(reader));
}
if (baseParser == null)
{
throw new ArgumentNullException(nameof(baseParser));
}
if (pool == null)
{
throw new ArgumentNullException(nameof(pool));
}
ReadHelper.ReadExpectedChar(reader, '<');
ReadHelper.ReadExpectedChar(reader, '<');
ReadHelper.SkipSpaces(reader);
var dictionary = new PdfDictionary();
var done = false;
while (!done)
{
ReadHelper.SkipSpaces(reader);
var c = (char)reader.Peek();
switch (c)
{
case '>':
done = true;
break;
case '/':
var nameValue = ParseCosDictionaryNameValuePair(reader, baseParser, pool);
if (nameValue.key != null && nameValue.value != null)
{
dictionary.Set(nameValue.key, nameValue.value);
}
break;
default:
if (ReadUntilEnd(reader))
{
return(new PdfDictionary());
}
break;
}
}
ReadHelper.ReadExpectedString(reader, ">>");
return(dictionary);
}
private static CosBase ParseValue(IRandomAccessRead reader, IBaseParser baseParser, CosObjectPool pool)
{
var numOffset = reader.GetPosition();
var value = baseParser.Parse(reader, pool);
ReadHelper.SkipSpaces(reader);
// proceed if the given object is a number and the following is a number as well
if (!(value is ICosNumber) || !ReadHelper.IsDigit(reader))
{
return(value);
}
// read the remaining information of the object number
var genOffset = reader.GetPosition();
var generationNumber = baseParser.Parse(reader, pool);
ReadHelper.SkipSpaces(reader);
ReadHelper.ReadExpectedChar(reader, 'R');
if (!(value is CosInt))
{
throw new InvalidOperationException("expected number, actual=" + value + " at offset " + numOffset);
}
if (!(generationNumber is CosInt))
{
throw new InvalidOperationException("expected number, actual=" + value + " at offset " + genOffset);
}
var key = new CosObjectKey(((CosInt)value).AsLong(), ((CosInt)generationNumber).AsInt());
// dereference the object
return(pool.Get(key));
}
private (CosName key, CosBase value) ParseCosDictionaryNameValuePair(IRandomAccessRead reader, IBaseParser baseParser, CosObjectPool pool)
{
var key = nameParser.Parse(reader);
var value = ParseValue(reader, baseParser, pool);
ReadHelper.SkipSpaces(reader);
if ((char)reader.Peek() == 'd')
{
// if the next string is 'def' then we are parsing a cmap stream
// and want to ignore it, otherwise throw an exception.
var potentialDef = ReadHelper.ReadString(reader);
if (!potentialDef.Equals("def"))
{
reader.Unread(OtherEncodings.StringAsLatin1Bytes(potentialDef));
}
else
{
ReadHelper.SkipSpaces(reader);
}
}
if (value == null)
{
log?.Warn("Bad Dictionary Declaration " + ReadHelper.ReadString(reader));
return(null, null);
}
// label this item as direct, to avoid signature problems.
value.Direct = true;
return(key, value);
}
public COSArray Parse(IRandomAccessRead reader, CosBaseParser baseParser, CosObjectPool pool)
{
ReadHelper.ReadExpectedChar(reader, '[');
var po = new COSArray();
CosBase pbo;
ReadHelper.SkipSpaces(reader);
int i;
while (((i = reader.Peek()) > 0) && ((char)i != ']'))
{
pbo = baseParser.Parse(reader, pool);
if (pbo is CosObject)
{
// We have to check if the expected values are there or not PDFBOX-385
if (po.get(po.size() - 1) is CosInt)
{
var genNumber = (CosInt)po.remove(po.size() - 1);
if (po.get(po.size() - 1) is CosInt)
{
var number = (CosInt)po.remove(po.size() - 1);
CosObjectKey key = new CosObjectKey(number.AsLong(), genNumber.AsInt());
pbo = pool.Get(key);
}
else
{
// the object reference is somehow wrong
pbo = null;
}
}
else
{
pbo = null;
}
}
if (pbo != null)
{
po.add(pbo);
}
else
{
//it could be a bad object in the array which is just skipped
// LOG.warn("Corrupt object reference at offset " + seqSource.getPosition());
// This could also be an "endobj" or "endstream" which means we can assume that
// the array has ended.
string isThisTheEnd = ReadHelper.ReadString(reader);
reader.Unread(OtherEncodings.StringAsLatin1Bytes(isThisTheEnd));
if (string.Equals(isThisTheEnd, "endobj") || string.Equals(isThisTheEnd, "endstream"))
{
return(po);
}
}
ReadHelper.SkipSpaces(reader);
}
// read ']'
reader.Read();
ReadHelper.SkipSpaces(reader);
return(po);
}
public CosBase Parse(IRandomAccessRead reader, CosObjectPool pool)
{
CosBase retval = null;
ReadHelper.SkipSpaces(reader);
int nextByte = reader.Peek();
if (nextByte == -1)
{
return(null);
}
char c = (char)nextByte;
switch (c)
{
case '<':
{
// pull off first left bracket
int leftBracket = reader.Read();
// check for second left bracket
c = (char)reader.Peek();
reader.Unread(leftBracket);
if (c == '<')
{
retval = dictionaryParser.Parse(reader, this, pool);
ReadHelper.SkipSpaces(reader);
}
else
{
retval = stringParser.Parse(reader);
}
break;
}
case '[':
{
// array
retval = arrayParser.Parse(reader, this, pool);
break;
}
case '(':
retval = stringParser.Parse(reader);
break;
case '/':
// name
retval = nameParser.Parse(reader);
break;
case 'n':
{
// null
ReadHelper.ReadExpectedString(reader, "null");
retval = CosNull.Null;
break;
}
case 't':
{
string truestring = OtherEncodings.BytesAsLatin1String(reader.ReadFully(4));
if (truestring.Equals("true"))
{
retval = PdfBoolean.True;
}
else
{
throw new IOException("expected true actual='" + truestring + "' " + reader +
"' at offset " + reader.GetPosition());
}
break;
}
case 'f':
{
string falsestring = OtherEncodings.BytesAsLatin1String(reader.ReadFully(5));
if (falsestring.Equals("false"))
{
retval = PdfBoolean.False;
}
else
{
throw new IOException("expected false actual='" + falsestring + "' " + reader +
"' at offset " + reader.GetPosition());
}
break;
}
case 'R':
reader.Read();
retval = new CosObject(null);
break;
default:
if (char.IsDigit(c) || c == '-' || c == '+' || c == '.')
{
StringBuilder buf = new StringBuilder();
int ic = reader.Read();
c = (char)ic;
while (char.IsDigit(c) ||
c == '-' ||
c == '+' ||
c == '.' ||
c == 'E' ||
c == 'e')
{
buf.Append(c);
ic = reader.Read();
c = (char)ic;
}
if (ic != -1)
{
reader.Unread(ic);
}
retval = CosNumberFactory.get(buf.ToString()) as CosBase;
}
else
{
//This is not suppose to happen, but we will allow for it
//so we are more compatible with POS writers that don't
//follow the spec
string badstring = ReadHelper.ReadString(reader);
if (badstring == string.Empty)
{
int peek = reader.Peek();
// we can end up in an infinite loop otherwise
throw new IOException("Unknown dir object c='" + c +
"' cInt=" + (int)c + " peek='" + (char)peek
+ "' peekInt=" + peek + " at offset " + reader.GetPosition());
}
// if it's an endstream/endobj, we want to put it back so the caller will see it
if (string.Equals("endobj", badstring) || string.Equals("endstream", badstring))
{
reader.Unread(OtherEncodings.StringAsLatin1Bytes(badstring));
}
}
break;
}
return(retval);
}
