Package com.itextpdf.kernel.pdf
Class MemoryLimitsAwareHandler
java.lang.Object
com.itextpdf.kernel.pdf.MemoryLimitsAwareHandler
A
MemoryLimitsAwareHandler
handles memory allocation and prevents decompressed
pdf streams from occupation of more space than allowed.
A configured MemoryLimitsAwareHandler can be set as a property of ReaderProperties
instance which is passed to PdfReader
.
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Field Summary
FieldsModifier and TypeFieldDescriptionprivate long
(package private) boolean
private static final int
private static final long
private int
private long
private int
private long
private long
private static final int
private static final int
private static final int
private static final long
private static final int
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Constructor Summary
ConstructorsModifierConstructorDescriptionCreates aMemoryLimitsAwareHandler
which will be used to handle decompression of pdf streams.private
MemoryLimitsAwareHandler
(int maxSizeOfSingleDecompressedPdfStream, long maxSizeOfDecompressedPdfStreamsSum, int maxNumberOfElementsInXrefStructure, long maxXObjectsSizePerPage) MemoryLimitsAwareHandler
(long documentSize) Creates aMemoryLimitsAwareHandler
which will be used to handle decompression of pdf streams. -
Method Summary
Modifier and TypeMethodDescription(package private) MemoryLimitsAwareHandler
Begins handling of current pdf stream decompression.private static long
calculateDefaultParameter
(long documentSize, int scale, long min) protected static int
calculateMaxElementsInXref
(long documentSizeInBytes) Calculate max number of elements allowed in xref table based on the size of the document, achieving max limit at 100MB.void
checkIfPageSizeExceedsTheLimit
(long totalXObjectsSize) void
checkIfXrefStructureExceedsTheLimit
(int requestedCapacity) Performs a check of possible extension of xref structure.(package private) MemoryLimitsAwareHandler
considerBytesOccupiedByDecompressedPdfStream
(long numOfOccupiedBytes) Considers the number of bytes which are occupied by the decompressed pdf stream.(package private) MemoryLimitsAwareHandler
Ends handling of current pdf stream decompression.private void
(package private) long
int
Gets maximum number of elements in xref structure.long
Gets the maximum allowed size which can be occupied by all decompressed pdf streams.int
Gets the maximum allowed size which can be occupied by a single decompressed pdf stream.long
Gets maximum page size.boolean
Performs a check if thePdfStream
with provided setup of the filters requires memory limits awareness during decompression.void
setMaxNumberOfElementsInXrefStructure
(int maxNumberOfElementsInXrefStructure) Sets maximum number of elements in xref structure.setMaxSizeOfDecompressedPdfStreamsSum
(long maxSizeOfDecompressedPdfStreamsSum) Sets the maximum allowed size which can be occupied by all decompressed pdf streams.setMaxSizeOfSingleDecompressedPdfStream
(int maxSizeOfSingleDecompressedPdfStream) Sets the maximum allowed size which can be occupied by a single decompressed pdf stream.void
setMaxXObjectsSizePerPage
(long maxPageSize) Sets maximum page size.
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Field Details
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SINGLE_SCALE_COEFFICIENT
private static final int SINGLE_SCALE_COEFFICIENT- See Also:
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SUM_SCALE_COEFFICIENT
private static final int SUM_SCALE_COEFFICIENT- See Also:
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MAX_NUMBER_OF_ELEMENTS_IN_XREF_STRUCTURE
private static final int MAX_NUMBER_OF_ELEMENTS_IN_XREF_STRUCTURE- See Also:
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MIN_LIMIT_FOR_NUMBER_OF_ELEMENTS_IN_XREF_STRUCTURE
private static final int MIN_LIMIT_FOR_NUMBER_OF_ELEMENTS_IN_XREF_STRUCTURE- See Also:
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SINGLE_DECOMPRESSED_PDF_STREAM_MIN_SIZE
private static final int SINGLE_DECOMPRESSED_PDF_STREAM_MIN_SIZE- See Also:
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SUM_OF_DECOMPRESSED_PDF_STREAMS_MIN_SIZE
private static final long SUM_OF_DECOMPRESSED_PDF_STREAMS_MIN_SIZE- See Also:
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MAX_X_OBJECTS_SIZE_PER_PAGE
private static final long MAX_X_OBJECTS_SIZE_PER_PAGE- See Also:
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maxSizeOfSingleDecompressedPdfStream
private int maxSizeOfSingleDecompressedPdfStream -
maxSizeOfDecompressedPdfStreamsSum
private long maxSizeOfDecompressedPdfStreamsSum -
maxNumberOfElementsInXrefStructure
private int maxNumberOfElementsInXrefStructure -
maxXObjectsSizePerPage
private long maxXObjectsSizePerPage -
allMemoryUsedForDecompression
private long allMemoryUsedForDecompression -
memoryUsedForCurrentPdfStreamDecompression
private long memoryUsedForCurrentPdfStreamDecompression -
considerCurrentPdfStream
boolean considerCurrentPdfStream
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Constructor Details
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MemoryLimitsAwareHandler
public MemoryLimitsAwareHandler()Creates aMemoryLimitsAwareHandler
which will be used to handle decompression of pdf streams. The max allowed memory limits will be generated by default. -
MemoryLimitsAwareHandler
public MemoryLimitsAwareHandler(long documentSize) Creates aMemoryLimitsAwareHandler
which will be used to handle decompression of pdf streams. The max allowed memory limits will be generated by default, based on the size of the document.- Parameters:
documentSize
- the size of the document, which is going to be handled by iText.
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MemoryLimitsAwareHandler
private MemoryLimitsAwareHandler(int maxSizeOfSingleDecompressedPdfStream, long maxSizeOfDecompressedPdfStreamsSum, int maxNumberOfElementsInXrefStructure, long maxXObjectsSizePerPage)
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Method Details
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getMaxSizeOfSingleDecompressedPdfStream
public int getMaxSizeOfSingleDecompressedPdfStream()Gets the maximum allowed size which can be occupied by a single decompressed pdf stream.- Returns:
- the maximum allowed size which can be occupied by a single decompressed pdf stream.
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setMaxSizeOfSingleDecompressedPdfStream
public MemoryLimitsAwareHandler setMaxSizeOfSingleDecompressedPdfStream(int maxSizeOfSingleDecompressedPdfStream) Sets the maximum allowed size which can be occupied by a single decompressed pdf stream. This value correlates with maximum heap size. This value should not exceed limit of the heap size.iText will throw an exception if during decompression a pdf stream which was identified as requiring memory limits awareness occupies more memory than allowed.
- Parameters:
maxSizeOfSingleDecompressedPdfStream
- the maximum allowed size which can be occupied by a single decompressed pdf stream.- Returns:
- this
MemoryLimitsAwareHandler
instance. - See Also:
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getMaxSizeOfDecompressedPdfStreamsSum
public long getMaxSizeOfDecompressedPdfStreamsSum()Gets the maximum allowed size which can be occupied by all decompressed pdf streams.- Returns:
- the maximum allowed size value which streams may occupy
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setMaxSizeOfDecompressedPdfStreamsSum
public MemoryLimitsAwareHandler setMaxSizeOfDecompressedPdfStreamsSum(long maxSizeOfDecompressedPdfStreamsSum) Sets the maximum allowed size which can be occupied by all decompressed pdf streams. This value can be limited by the maximum expected PDF file size when it's completely decompressed. Setting this value correlates with the maximum processing time spent on document readingiText will throw an exception if during decompression pdf streams which were identified as requiring memory limits awareness occupy more memory than allowed.
- Parameters:
maxSizeOfDecompressedPdfStreamsSum
- he maximum allowed size which can be occupied by all decompressed pdf streams.- Returns:
- this
MemoryLimitsAwareHandler
instance. - See Also:
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isMemoryLimitsAwarenessRequiredOnDecompression
Performs a check if thePdfStream
with provided setup of the filters requires memory limits awareness during decompression.- Parameters:
filters
- is anPdfArray
of names of filters- Returns:
- true if PDF stream is suspicious and false otherwise
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getMaxNumberOfElementsInXrefStructure
public int getMaxNumberOfElementsInXrefStructure()Gets maximum number of elements in xref structure.- Returns:
- maximum number of elements in xref structure.
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getMaxXObjectsSizePerPage
public long getMaxXObjectsSizePerPage()Gets maximum page size.- Returns:
- maximum page size.
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setMaxXObjectsSizePerPage
public void setMaxXObjectsSizePerPage(long maxPageSize) Sets maximum page size.- Parameters:
maxPageSize
- maximum page size.
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setMaxNumberOfElementsInXrefStructure
public void setMaxNumberOfElementsInXrefStructure(int maxNumberOfElementsInXrefStructure) Sets maximum number of elements in xref structure.- Parameters:
maxNumberOfElementsInXrefStructure
- maximum number of elements in xref structure.
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checkIfXrefStructureExceedsTheLimit
public void checkIfXrefStructureExceedsTheLimit(int requestedCapacity) Performs a check of possible extension of xref structure.- Parameters:
requestedCapacity
- capacity to which we need to expand xref array.
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checkIfPageSizeExceedsTheLimit
public void checkIfPageSizeExceedsTheLimit(long totalXObjectsSize) -
calculateMaxElementsInXref
protected static int calculateMaxElementsInXref(long documentSizeInBytes) Calculate max number of elements allowed in xref table based on the size of the document, achieving max limit at 100MB.- Parameters:
documentSizeInBytes
- document size in bytes.- Returns:
- calculated limit.
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considerBytesOccupiedByDecompressedPdfStream
Considers the number of bytes which are occupied by the decompressed pdf stream. If memory limits have not been faced, throws an exception.- Parameters:
numOfOccupiedBytes
- the number of bytes which are occupied by the decompressed pdf stream.- Returns:
- this
MemoryLimitsAwareHandler
instance. - See Also:
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beginDecompressedPdfStreamProcessing
MemoryLimitsAwareHandler beginDecompressedPdfStreamProcessing()Begins handling of current pdf stream decompression.- Returns:
- this
MemoryLimitsAwareHandler
instance.
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endDecompressedPdfStreamProcessing
MemoryLimitsAwareHandler endDecompressedPdfStreamProcessing()Ends handling of current pdf stream decompression. If memory limits have not been faced, throws an exception.- Returns:
- this
MemoryLimitsAwareHandler
instance. - See Also:
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getAllMemoryUsedForDecompression
long getAllMemoryUsedForDecompression() -
calculateDefaultParameter
private static long calculateDefaultParameter(long documentSize, int scale, long min) -
ensureCurrentStreamIsReset
private void ensureCurrentStreamIsReset()
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