Package org.apache.pdfbox.pdfparser
Class COSParser
java.lang.Object
org.apache.pdfbox.pdfparser.BaseParser
org.apache.pdfbox.pdfparser.COSParser
PDF-Parser which first reads startxref and xref tables in order to know valid objects and parse only these objects.
First
PDFParser.parse()
or FDFParser.parse()
must be called before page objects
can be retrieved, e.g. PDFParser.getPDDocument()
.
This class is a much enhanced version of QuickParser
presented in PDFBOX-1104 by Jeremy Villalobos.-
Field Summary
FieldsModifier and TypeFieldDescriptionprotected static final char[]
EOF-marker.protected long
file length.protected boolean
protected static final char[]
obj-marker.protected SecurityHandler
The security handler.protected final RandomAccessRead
static final String
The range within the %%EOF marker will be searched.static final String
Only parse the PDF file minimally allowing access to basic information.static final String
The prefix for the temp file being used.protected XrefTrailerResolver
Collects all Xref/trailer objects and resolves them into single object using startxref reference.Fields inherited from class org.apache.pdfbox.pdfparser.BaseParser
A, ASCII_CR, ASCII_LF, B, D, DEF, document, E, ENDOBJ_STRING, ENDSTREAM_STRING, J, M, N, O, R, S, STREAM_STRING, T
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Constructor Summary
ConstructorsConstructorDescriptionCOSParser
(RandomAccessRead source) Default constructor.COSParser
(RandomAccessRead source, String password, InputStream keyStore, String keyAlias) Constructor for encrypted pdfs. -
Method Summary
Modifier and TypeMethodDescriptionprotected void
checkPages
(COSDictionary root) Check if all entries of the pages dictionary are present.This will get the AccessPermission.This will get the document that was parsed.This will get the encryption dictionary.protected final long
Looks for and parses startxref.protected boolean
isCatalog
(COSDictionary dictionary) Tell if the dictionary is a PDF catalog.boolean
Return true if parser is lenient.protected int
lastIndexOf
(char[] pattern, byte[] buf, int endOff) Searches last appearance of pattern within buffer.protected COSStream
This will read a COSStream from the input stream using length attribute within dictionary.protected void
parseDictObjects
(COSDictionary dict, COSName... excludeObjects) Will parse every object necessary to load a single page from the pdf document.protected boolean
Parse the header of a fdf.protected COSBase
parseObjectDynamically
(long objNr, int objGenNr, boolean requireExistingNotCompressedObj) This will parse the next object from the stream and add it to the local state.protected final COSBase
parseObjectDynamically
(COSObject obj, boolean requireExistingNotCompressedObj) This will parse the next object from the stream and add it to the local state.protected boolean
Parse the header of a pdf.protected COSBase
Parse the values of the trailer dictionary and return the root object.protected COSDictionary
parseXref
(long startXRefOffset) Parses cross reference tables.protected boolean
parseXrefTable
(long startByteOffset) This will parse the xref table from the stream and add it to the state The XrefTable contents are ignored.protected final COSDictionary
Rebuild the trailer dictionary if startxref can't be found.protected COSDictionary
Read the trailer information and provide a COSDictionary containing the trailer information.void
setEOFLookupRange
(int byteCount) Sets how many trailing bytes of PDF file are searched for EOF marker and 'startxref' marker.void
setLenient
(boolean lenient) Change the parser leniency flag.Methods inherited from class org.apache.pdfbox.pdfparser.BaseParser
isClosing, isClosing, isDigit, isDigit, isEndOfName, isEOL, isEOL, isSpace, isSpace, isWhitespace, isWhitespace, parseBoolean, parseCOSArray, parseCOSDictionary, parseCOSName, parseCOSString, parseDirObject, readExpectedChar, readExpectedString, readExpectedString, readGenerationNumber, readInt, readLine, readLong, readObjectNumber, readString, readString, readStringNumber, skipSpaces, skipWhiteSpaces
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Field Details
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source
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SYSPROP_PARSEMINIMAL
Only parse the PDF file minimally allowing access to basic information.- See Also:
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SYSPROP_EOFLOOKUPRANGE
The range within the %%EOF marker will be searched. Useful if there are additional characters after %%EOF within the PDF.- See Also:
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EOF_MARKER
protected static final char[] EOF_MARKEREOF-marker. -
OBJ_MARKER
protected static final char[] OBJ_MARKERobj-marker. -
fileLen
protected long fileLenfile length. -
initialParseDone
protected boolean initialParseDone -
securityHandler
The security handler. -
xrefTrailerResolver
Collects all Xref/trailer objects and resolves them into single object using startxref reference. -
TMP_FILE_PREFIX
The prefix for the temp file being used.- See Also:
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Constructor Details
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COSParser
Default constructor.- Parameters:
source
- input representing the pdf.
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COSParser
Constructor for encrypted pdfs.- Parameters:
source
- input representing the pdf.password
- password to be used for decryption.keyStore
- key store to be used for decryption when using public key securitykeyAlias
- alias to be used for decryption when using public key security
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Method Details
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setEOFLookupRange
public void setEOFLookupRange(int byteCount) Sets how many trailing bytes of PDF file are searched for EOF marker and 'startxref' marker. If not set we use default valueDEFAULT_TRAIL_BYTECOUNT
.We check that new value is at least 16. However for practical use cases this value should not be lower than 1000; even 2000 was found to not be enough in some cases where some trailing garbage like HTML snippets followed the EOF marker.
In case system property
SYSPROP_EOFLOOKUPRANGE
is defined this value will be set on initialization but can be overwritten later.- Parameters:
byteCount
- number of trailing bytes
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retrieveTrailer
Read the trailer information and provide a COSDictionary containing the trailer information.- Returns:
- a COSDictionary containing the trailer information
- Throws:
IOException
- if something went wrong
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parseXref
Parses cross reference tables.- Parameters:
startXRefOffset
- start offset of the first table- Returns:
- the trailer dictionary
- Throws:
IOException
- if something went wrong
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getStartxrefOffset
Looks for and parses startxref. We first look for last '%%EOF' marker (within lastDEFAULT_TRAIL_BYTECOUNT
bytes (or range set viasetEOFLookupRange(int)
) and go back to findstartxref
.- Returns:
- the offset of StartXref
- Throws:
IOException
- If something went wrong.
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lastIndexOf
protected int lastIndexOf(char[] pattern, byte[] buf, int endOff) Searches last appearance of pattern within buffer. Lookup before _lastOff and goes back until 0.- Parameters:
pattern
- pattern to search forbuf
- buffer to search pattern inendOff
- offset (exclusive) where lookup starts at- Returns:
- start offset of pattern within buffer or
-1
if pattern could not be found
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isLenient
public boolean isLenient()Return true if parser is lenient. Meaning auto healing capacity of the parser are used.- Returns:
- true if parser is lenient
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setLenient
public void setLenient(boolean lenient) Change the parser leniency flag. This method can only be called before the parsing of the file.- Parameters:
lenient
- try to handle malformed PDFs.
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parseDictObjects
Will parse every object necessary to load a single page from the pdf document. We try our best to order objects according to offset in file before reading to minimize seek operations.- Parameters:
dict
- the COSObject from the parent pages.excludeObjects
- dictionary object reference entries with these names will not be parsed- Throws:
IOException
- if something went wrong
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parseObjectDynamically
protected final COSBase parseObjectDynamically(COSObject obj, boolean requireExistingNotCompressedObj) throws IOException This will parse the next object from the stream and add it to the local state.- Parameters:
obj
- object to be parsed (we only take object number and generation number for lookup start offset)requireExistingNotCompressedObj
- iftrue
object to be parsed must not be contained within compressed stream- Returns:
- the parsed object (which is also added to document object)
- Throws:
IOException
- If an IO error occurs.
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parseObjectDynamically
protected COSBase parseObjectDynamically(long objNr, int objGenNr, boolean requireExistingNotCompressedObj) throws IOException This will parse the next object from the stream and add it to the local state. It's reduced to parsing an indirect object.- Parameters:
objNr
- object number of object to be parsedobjGenNr
- object generation number of object to be parsedrequireExistingNotCompressedObj
- iftrue
the object to be parsed must be defined in xref (comment: null objects may be missing from xref) and it must not be a compressed object within object stream (this is used to circumvent being stuck in a loop in a malicious PDF)- Returns:
- the parsed object (which is also added to document object)
- Throws:
IOException
- If an IO error occurs.
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parseCOSStream
This will read a COSStream from the input stream using length attribute within dictionary. If length attribute is a indirect reference it is first resolved to get the stream length. This means we copy stream data without testing for 'endstream' or 'endobj' and thus it is no problem if these keywords occur within stream. We require 'endstream' to be found after stream data is read.- Parameters:
dic
- dictionary that goes with this stream.- Returns:
- parsed pdf stream.
- Throws:
IOException
- if an error occurred reading the stream, like problems with reading length attribute, stream does not end with 'endstream' after data read, stream too short etc.
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rebuildTrailer
Rebuild the trailer dictionary if startxref can't be found.- Returns:
- the rebuild trailer dictionary
- Throws:
IOException
- if something went wrong
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checkPages
Check if all entries of the pages dictionary are present. Those which can't be dereferenced are removed.- Parameters:
root
- the root dictionary of the pdf
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isCatalog
Tell if the dictionary is a PDF catalog. Override this for an FDF catalog.- Parameters:
dictionary
-- Returns:
- true if the given dictionary is a root dictionary
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parsePDFHeader
Parse the header of a pdf.- Returns:
- true if a PDF header was found
- Throws:
IOException
- if something went wrong
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parseFDFHeader
Parse the header of a fdf.- Returns:
- true if a FDF header was found
- Throws:
IOException
- if something went wrong
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parseXrefTable
This will parse the xref table from the stream and add it to the state The XrefTable contents are ignored.- Parameters:
startByteOffset
- the offset to start at- Returns:
- false on parsing error
- Throws:
IOException
- If an IO error occurs.
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getDocument
This will get the document that was parsed. The document must be parsed before this is called. When you are done with this document you must call close() on it to release resources.- Returns:
- The document that was parsed.
- Throws:
IOException
- If there is an error getting the document.
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getEncryption
This will get the encryption dictionary. The document must be parsed before this is called.- Returns:
- The encryption dictionary of the document that was parsed.
- Throws:
IOException
- If there is an error getting the document.
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getAccessPermission
This will get the AccessPermission. The document must be parsed before this is called.- Returns:
- The access permission of document that was parsed.
- Throws:
IOException
- If there is an error getting the document.
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parseTrailerValuesDynamically
Parse the values of the trailer dictionary and return the root object.- Parameters:
trailer
- The trailer dictionary.- Returns:
- The parsed root object.
- Throws:
IOException
- If an IO error occurs or if the root object is missing in the trailer dictionary.
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