[jira] [Updated] (PDFBOX-5708) Remove duplicate Embedded Subsets of font in PDF

["ma hei pang (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/PDFBOX-5708?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

ma hei pang updated PDFBOX-5708:
--------------------------------
    Description: 
I am using pdfbox-2.0.24 to merge multiple PDFs. However, the merged file size is too large because it contains many duplicate embedded subsets of font. For an example, I merge 1.pdf and 2.pdf which shows some repeated font list as picture1. 

 

I tried the source code provided by mkl : [How to reduce the size of merged PDF/A-1b files with pdfbox or other java library - Stack Overflow|https://stackoverflow.com/questions/53420344/how-to-reduce-the-size-of-merged-pdf-a-1b-files-with-pdfbox-or-other-java-librar/53544377#53544377]
{code:java}
import org.apache.pdfbox.cos.*; import org.apache.pdfbox.pdmodel.PDDocument; import java.io.File; import java.io.IOException; import java.io.InputStream; import java.security.MessageDigest; import java.security.NoSuchAlgorithmException; import java.util.*; public class PdfOptimizer { public PdfOptimizer() {} public void optimize(PDDocument pdDocument) throws IOException { Map<COSBase, Collection<Reference>> complexObjects = findComplexObjects(pdDocument); for (int pass = 0; ; pass++) { int merges = mergeDuplicates(complexObjects); if (merges <= 0) { System.out.printf("Pass %d - No merged objects\n\n", pass); break; } System.out.printf("Pass %d - Merged objects: %d\n\n", pass, merges); } } Map<COSBase, Collection<Reference>> findComplexObjects(PDDocument pdDocument) { // Implementation of findComplexObjects method COSDictionary catalogDictionary = pdDocument.getDocumentCatalog().getCOSObject(); Map<COSBase, Collection<Reference>> incomingReferences = new HashMap<>(); incomingReferences.put(catalogDictionary, new ArrayList<>()); Set<COSBase> lastPass = Collections.<COSBase>singleton(catalogDictionary); Set<COSBase> thisPass = new HashSet<>(); while(!lastPass.isEmpty()) { for (COSBase object : lastPass) { if (object instanceof COSArray) { COSArray array = (COSArray) object; for (int i = 0; i < array.size(); i++) { addTarget(new ArrayReference(array, i), incomingReferences, thisPass); } } else if (object instanceof COSDictionary) { COSDictionary dictionary = (COSDictionary) object; for (COSName key : dictionary.keySet()) { addTarget(new DictionaryReference(dictionary, key), incomingReferences, thisPass); } } } lastPass = thisPass; thisPass = new HashSet<>(); } return incomingReferences; } void addTarget(Reference reference, Map<COSBase, Collection<Reference>> incomingReferences, Set<COSBase> thisPass) { // Implementation of addTarget method COSBase object = reference.getTo(); if (object instanceof COSArray || object instanceof COSDictionary) { Collection<Reference> incoming = incomingReferences.get(object); if (incoming == null) { incoming = new ArrayList<>(); incomingReferences.put(object, incoming); thisPass.add(object); } incoming.add(reference); } } int mergeDuplicates(Map<COSBase, Collection<Reference>> complexObjects) throws IOException { // Implementation of mergeDuplicates method List<HashOfCOSBase> hashes = new ArrayList<>(complexObjects.size()); for (COSBase object : complexObjects.keySet()) { hashes.add(new HashOfCOSBase(object)); } Collections.sort(hashes); int removedDuplicates = 0; if (!hashes.isEmpty()) { int runStart = 0; int runHash = hashes.get(0).hash; for (int i = 1; i < hashes.size(); i++) { int hash = hashes.get(i).hash; if (hash != runHash) { int runSize = i - runStart; if (runSize != 1) { System.out.printf("Equal hash %d for %d elements.\n", runHash, runSize); removedDuplicates += mergeRun(complexObjects, hashes.subList(runStart, i)); } runHash = hash; runStart = i; } } int runSize = hashes.size() - runStart; if (runSize != 1) { System.out.printf("Equal hash %d for %d elements.\n", runHash, runSize); removedDuplicates += mergeRun(complexObjects, hashes.subList(runStart, hashes.size())); } } return removedDuplicates; } int mergeRun(Map<COSBase, Collection<Reference>> complexObjects, List<HashOfCOSBase> run) { // Implementation of mergeRun method int removedDuplicates = 0; List<List<COSBase>> duplicateSets = new ArrayList<>(); for (HashOfCOSBase entry : run) { COSBase element = entry.object; for (List<COSBase> duplicateSet : duplicateSets) { if (equals(element, duplicateSet.get(0))) { duplicateSet.add(element); element = null; break; } } if (element != null) { List<COSBase> duplicateSet = new ArrayList<>(); duplicateSet.add(element); duplicateSets.add(duplicateSet); } } System.out.printf("Identified %d set(s) of identical objects in run.\n", duplicateSets.size()); for (List<COSBase> duplicateSet : duplicateSets) { if (duplicateSet.size() > 1) { COSBase surviver = duplicateSet.remove(0); Collection<Reference> surviverReferences = complexObjects.get(surviver); for (COSBase object : duplicateSet) { Collection<Reference> references = complexObjects.get(object); for (Reference reference : references) { reference.setTo(surviver); surviverReferences.add(reference); } complexObjects.remove(object); removedDuplicates++; } surviver.setDirect(false); } } return removedDuplicates; } boolean equals(COSBase a, COSBase b) { // Implementation of equals method if (a instanceof COSArray) { if (b instanceof COSArray) { COSArray aArray = (COSArray) a; COSArray bArray = (COSArray) b; if (aArray.size() == bArray.size()) { for (int i=0; i < aArray.size(); i++) { if (!resolve(aArray.get(i)).equals(resolve(bArray.get(i)))) return false; } return true; } } } else if (a instanceof COSDictionary) { if (b instanceof COSDictionary) { COSDictionary aDict = (COSDictionary) a; COSDictionary bDict = (COSDictionary) b; Set<COSName> keys = aDict.keySet(); if (keys.equals(bDict.keySet())) { for (COSName key : keys) { if (!resolve(aDict.getItem(key)).equals(bDict.getItem(key))) return false; } // In case of COSStreams we strictly speaking should // also compare the stream contents here. But apparently // their hashes coincide well enough for the original // hashing equality, so let's just assume... return true; } } } return false; } static COSBase resolve(COSBase object) { // Implementation of resolve method while (object instanceof COSObject) object = ((COSObject)object).getObject(); return object; } interface Reference { public COSBase getFrom(); public COSBase getTo(); public void setTo(COSBase to); } static class ArrayReference implements Reference { public ArrayReference(COSArray array, int index) { this.from = array; this.index = index; } @Override public COSBase getFrom() { return from; } @Override public COSBase getTo() { return resolve(from.get(index)); } @Override public void setTo(COSBase to) { from.set(index, to); } final COSArray from; final int index; } static class DictionaryReference implements Reference { public DictionaryReference(COSDictionary dictionary, COSName key) { this.from = dictionary; this.key = key; } @Override public COSBase getFrom() { return from; } @Override public COSBase getTo() { return resolve(from.getDictionaryObject(key)); } @Override public void setTo(COSBase to) { from.setItem(key, to); } final COSDictionary from; final COSName key; } static class HashOfCOSBase implements Comparable<HashOfCOSBase> { public HashOfCOSBase(COSBase object) throws IOException { this.object = object; this.hash = calculateHash(object); } int calculateHash(COSBase object) throws IOException { if (object instanceof COSArray) { int result = 1; for (COSBase member : (COSArray)object) result = 31 * result + member.hashCode(); return result; } else if (object instanceof COSDictionary) { int result = 3; for (Map.Entry<COSName, COSBase> entry : ((COSDictionary)object).entrySet()) result += entry.hashCode(); if (object instanceof COSStream) { try ( InputStream data = ((COSStream)object).createRawInputStream() ) { MessageDigest md = MessageDigest.getInstance("MD5"); byte[] buffer = new byte[8192]; int bytesRead = 0; while((bytesRead = data.read(buffer)) >= 0) md.update(buffer, 0, bytesRead); result = 31 * result + Arrays.hashCode(md.digest()); } catch (NoSuchAlgorithmException e) { throw new IOException(e); } } return result; } else { throw new IllegalArgumentException(String.format("Unknown complex COSBase type %s", object.getClass().getName())); } } final COSBase object; final int hash; @Override public int compareTo(HashOfCOSBase o) { int result = Integer.compare(hash, o.hash); if (result == 0) result = Integer.compare(hashCode(), o.hashCode()); return result; } } } {code}
 

However, it is not working for me. Can anyone have an idea to remove the duplicate embedded subsets of font in merging PDFs?

 

 

 

  was:
I am using pdfbox-2.0.24 to merge multiple PDFs. However, the merged file size is too large because it contains many duplicate embedded subsets of font. For an example, I merge 1.pdf and 2.pdf which shows some repeated font list as picture1. 

 

I tried the source code provided by mkl : [How to reduce the size of merged PDF/A-1b files with pdfbox or other java library - Stack Overflow|https://stackoverflow.com/questions/53420344/how-to-reduce-the-size-of-merged-pdf-a-1b-files-with-pdfbox-or-other-java-librar/53544377#53544377]
{code:java}
// code placeholder
{code}
import org.apache.pdfbox.cos.*; import org.apache.pdfbox.pdmodel.PDDocument; import java.io.File; import java.io.IOException; import java.io.InputStream; import java.security.MessageDigest; import java.security.NoSuchAlgorithmException; import java.util.*; public class PdfOptimizer \{ public PdfOptimizer() {} public void optimize(PDDocument pdDocument) throws IOException \{ Map<COSBase, Collection<Reference>> complexObjects = findComplexObjects(pdDocument); for (int pass = 0; ; pass++) { int merges = mergeDuplicates(complexObjects); if (merges <= 0) { System.out.printf("Pass %d - No merged objects\n\n", pass); break; } System.out.printf("Pass %d - Merged objects: %d\n\n", pass, merges); } } Map<COSBase, Collection<Reference>> findComplexObjects(PDDocument pdDocument) \{ // Implementation of findComplexObjects method COSDictionary catalogDictionary = pdDocument.getDocumentCatalog().getCOSObject(); Map<COSBase, Collection<Reference>> incomingReferences = new HashMap<>(); incomingReferences.put(catalogDictionary, new ArrayList<>()); Set<COSBase> lastPass = Collections.<COSBase>singleton(catalogDictionary); Set<COSBase> thisPass = new HashSet<>(); while(!lastPass.isEmpty()) { for (COSBase object : lastPass) { if (object instanceof COSArray) { COSArray array = (COSArray) object; for (int i = 0; i < array.size(); i++) { addTarget(new ArrayReference(array, i), incomingReferences, thisPass); } } else if (object instanceof COSDictionary) \{ COSDictionary dictionary = (COSDictionary) object; for (COSName key : dictionary.keySet()) { addTarget(new DictionaryReference(dictionary, key), incomingReferences, thisPass); } } } lastPass = thisPass; thisPass = new HashSet<>(); } return incomingReferences; } void addTarget(Reference reference, Map<COSBase, Collection<Reference>> incomingReferences, Set<COSBase> thisPass) \{ // Implementation of addTarget method COSBase object = reference.getTo(); if (object instanceof COSArray || object instanceof COSDictionary) { Collection<Reference> incoming = incomingReferences.get(object); if (incoming == null) { incoming = new ArrayList<>(); incomingReferences.put(object, incoming); thisPass.add(object); } incoming.add(reference); } } int mergeDuplicates(Map<COSBase, Collection<Reference>> complexObjects) throws IOException \{ // Implementation of mergeDuplicates method List<HashOfCOSBase> hashes = new ArrayList<>(complexObjects.size()); for (COSBase object : complexObjects.keySet()) { hashes.add(new HashOfCOSBase(object)); } Collections.sort(hashes); int removedDuplicates = 0; if (!hashes.isEmpty()) \{ int runStart = 0; int runHash = hashes.get(0).hash; for (int i = 1; i < hashes.size(); i++) { int hash = hashes.get(i).hash; if (hash != runHash) { int runSize = i - runStart; if (runSize != 1) { System.out.printf("Equal hash %d for %d elements.\n", runHash, runSize); removedDuplicates += mergeRun(complexObjects, hashes.subList(runStart, i)); } runHash = hash; runStart = i; } } int runSize = hashes.size() - runStart; if (runSize != 1) \{ System.out.printf("Equal hash %d for %d elements.\n", runHash, runSize); removedDuplicates += mergeRun(complexObjects, hashes.subList(runStart, hashes.size())); } } return removedDuplicates; } int mergeRun(Map<COSBase, Collection<Reference>> complexObjects, List<HashOfCOSBase> run) \{ // Implementation of mergeRun method int removedDuplicates = 0; List<List<COSBase>> duplicateSets = new ArrayList<>(); for (HashOfCOSBase entry : run) { COSBase element = entry.object; for (List<COSBase> duplicateSet : duplicateSets) { if (equals(element, duplicateSet.get(0))) { duplicateSet.add(element); element = null; break; } } if (element != null) \{ List<COSBase> duplicateSet = new ArrayList<>(); duplicateSet.add(element); duplicateSets.add(duplicateSet); } } System.out.printf("Identified %d set(s) of identical objects in run.\n", duplicateSets.size()); for (List<COSBase> duplicateSet : duplicateSets) \{ if (duplicateSet.size() > 1) { COSBase surviver = duplicateSet.remove(0); Collection<Reference> surviverReferences = complexObjects.get(surviver); for (COSBase object : duplicateSet) { Collection<Reference> references = complexObjects.get(object); for (Reference reference : references) { reference.setTo(surviver); surviverReferences.add(reference); } complexObjects.remove(object); removedDuplicates++; } surviver.setDirect(false); } } return removedDuplicates; } boolean equals(COSBase a, COSBase b) \{ // Implementation of equals method if (a instanceof COSArray) { if (b instanceof COSArray) { COSArray aArray = (COSArray) a; COSArray bArray = (COSArray) b; if (aArray.size() == bArray.size()) { for (int i=0; i < aArray.size(); i++) { if (!resolve(aArray.get(i)).equals(resolve(bArray.get(i)))) return false; } return true; } } } else if (a instanceof COSDictionary) \{ if (b instanceof COSDictionary) { COSDictionary aDict = (COSDictionary) a; COSDictionary bDict = (COSDictionary) b; Set<COSName> keys = aDict.keySet(); if (keys.equals(bDict.keySet())) { for (COSName key : keys) { if (!resolve(aDict.getItem(key)).equals(bDict.getItem(key))) return false; } // In case of COSStreams we strictly speaking should // also compare the stream contents here. But apparently // their hashes coincide well enough for the original // hashing equality, so let's just assume... return true; } } } return false; } static COSBase resolve(COSBase object) \{ // Implementation of resolve method while (object instanceof COSObject) object = ((COSObject)object).getObject(); return object; } interface Reference \{ public COSBase getFrom(); public COSBase getTo(); public void setTo(COSBase to); } static class ArrayReference implements Reference \{ public ArrayReference(COSArray array, int index) { this.from = array; this.index = index; } @Override public COSBase getFrom() \{ return from; } @Override public COSBase getTo() \{ return resolve(from.get(index)); } @Override public void setTo(COSBase to) \{ from.set(index, to); } final COSArray from; final int index; } static class DictionaryReference implements Reference \{ public DictionaryReference(COSDictionary dictionary, COSName key) { this.from = dictionary; this.key = key; } @Override public COSBase getFrom() \{ return from; } @Override public COSBase getTo() \{ return resolve(from.getDictionaryObject(key)); } @Override public void setTo(COSBase to) \{ from.setItem(key, to); } final COSDictionary from; final COSName key; } static class HashOfCOSBase implements Comparable<HashOfCOSBase> \{ public HashOfCOSBase(COSBase object) throws IOException { this.object = object; this.hash = calculateHash(object); } int calculateHash(COSBase object) throws IOException \{ if (object instanceof COSArray) { int result = 1; for (COSBase member : (COSArray)object) result = 31 * result + member.hashCode(); return result; } else if (object instanceof COSDictionary) \{ int result = 3; for (Map.Entry<COSName, COSBase> entry : ((COSDictionary)object).entrySet()) result += entry.hashCode(); if (object instanceof COSStream) { try ( InputStream data = ((COSStream)object).createRawInputStream() ) { MessageDigest md = MessageDigest.getInstance("MD5"); byte[] buffer = new byte[8192]; int bytesRead = 0; while((bytesRead = data.read(buffer)) >= 0) md.update(buffer, 0, bytesRead); result = 31 * result + Arrays.hashCode(md.digest()); } catch (NoSuchAlgorithmException e) \{ throw new IOException(e); } } return result; } else \{ throw new IllegalArgumentException(String.format("Unknown complex COSBase type %s", object.getClass().getName())); } } final COSBase object; final int hash; @Override public int compareTo(HashOfCOSBase o) \{ int result = Integer.compare(hash, o.hash); if (result == 0) result = Integer.compare(hashCode(), o.hashCode()); return result; } } }

 

However, it is not working for me. Can anyone have an idea to remove the duplicate embedded subsets of font in merging PDFs?

 

 

 


> Remove duplicate Embedded Subsets of font in PDF
> ------------------------------------------------
>
>                 Key: PDFBOX-5708
>                 URL: https://issues.apache.org/jira/browse/PDFBOX-5708
>             Project: PDFBox
>          Issue Type: Wish
>          Components: PDModel
>    Affects Versions: 2.0.24
>            Reporter: ma hei pang
>            Priority: Major
>         Attachments: 1.pdf, 2.pdf, picture1.PNG
>
>
> I am using pdfbox-2.0.24 to merge multiple PDFs. However, the merged file size is too large because it contains many duplicate embedded subsets of font. For an example, I merge 1.pdf and 2.pdf which shows some repeated font list as picture1. 
>  
> I tried the source code provided by mkl : [How to reduce the size of merged PDF/A-1b files with pdfbox or other java library - Stack Overflow|https://stackoverflow.com/questions/53420344/how-to-reduce-the-size-of-merged-pdf-a-1b-files-with-pdfbox-or-other-java-librar/53544377#53544377]
> {code:java}
> import org.apache.pdfbox.cos.*; import org.apache.pdfbox.pdmodel.PDDocument; import java.io.File; import java.io.IOException; import java.io.InputStream; import java.security.MessageDigest; import java.security.NoSuchAlgorithmException; import java.util.*; public class PdfOptimizer { public PdfOptimizer() {} public void optimize(PDDocument pdDocument) throws IOException { Map<COSBase, Collection<Reference>> complexObjects = findComplexObjects(pdDocument); for (int pass = 0; ; pass++) { int merges = mergeDuplicates(complexObjects); if (merges <= 0) { System.out.printf("Pass %d - No merged objects\n\n", pass); break; } System.out.printf("Pass %d - Merged objects: %d\n\n", pass, merges); } } Map<COSBase, Collection<Reference>> findComplexObjects(PDDocument pdDocument) { // Implementation of findComplexObjects method COSDictionary catalogDictionary = pdDocument.getDocumentCatalog().getCOSObject(); Map<COSBase, Collection<Reference>> incomingReferences = new HashMap<>(); incomingReferences.put(catalogDictionary, new ArrayList<>()); Set<COSBase> lastPass = Collections.<COSBase>singleton(catalogDictionary); Set<COSBase> thisPass = new HashSet<>(); while(!lastPass.isEmpty()) { for (COSBase object : lastPass) { if (object instanceof COSArray) { COSArray array = (COSArray) object; for (int i = 0; i < array.size(); i++) { addTarget(new ArrayReference(array, i), incomingReferences, thisPass); } } else if (object instanceof COSDictionary) { COSDictionary dictionary = (COSDictionary) object; for (COSName key : dictionary.keySet()) { addTarget(new DictionaryReference(dictionary, key), incomingReferences, thisPass); } } } lastPass = thisPass; thisPass = new HashSet<>(); } return incomingReferences; } void addTarget(Reference reference, Map<COSBase, Collection<Reference>> incomingReferences, Set<COSBase> thisPass) { // Implementation of addTarget method COSBase object = reference.getTo(); if (object instanceof COSArray || object instanceof COSDictionary) { Collection<Reference> incoming = incomingReferences.get(object); if (incoming == null) { incoming = new ArrayList<>(); incomingReferences.put(object, incoming); thisPass.add(object); } incoming.add(reference); } } int mergeDuplicates(Map<COSBase, Collection<Reference>> complexObjects) throws IOException { // Implementation of mergeDuplicates method List<HashOfCOSBase> hashes = new ArrayList<>(complexObjects.size()); for (COSBase object : complexObjects.keySet()) { hashes.add(new HashOfCOSBase(object)); } Collections.sort(hashes); int removedDuplicates = 0; if (!hashes.isEmpty()) { int runStart = 0; int runHash = hashes.get(0).hash; for (int i = 1; i < hashes.size(); i++) { int hash = hashes.get(i).hash; if (hash != runHash) { int runSize = i - runStart; if (runSize != 1) { System.out.printf("Equal hash %d for %d elements.\n", runHash, runSize); removedDuplicates += mergeRun(complexObjects, hashes.subList(runStart, i)); } runHash = hash; runStart = i; } } int runSize = hashes.size() - runStart; if (runSize != 1) { System.out.printf("Equal hash %d for %d elements.\n", runHash, runSize); removedDuplicates += mergeRun(complexObjects, hashes.subList(runStart, hashes.size())); } } return removedDuplicates; } int mergeRun(Map<COSBase, Collection<Reference>> complexObjects, List<HashOfCOSBase> run) { // Implementation of mergeRun method int removedDuplicates = 0; List<List<COSBase>> duplicateSets = new ArrayList<>(); for (HashOfCOSBase entry : run) { COSBase element = entry.object; for (List<COSBase> duplicateSet : duplicateSets) { if (equals(element, duplicateSet.get(0))) { duplicateSet.add(element); element = null; break; } } if (element != null) { List<COSBase> duplicateSet = new ArrayList<>(); duplicateSet.add(element); duplicateSets.add(duplicateSet); } } System.out.printf("Identified %d set(s) of identical objects in run.\n", duplicateSets.size()); for (List<COSBase> duplicateSet : duplicateSets) { if (duplicateSet.size() > 1) { COSBase surviver = duplicateSet.remove(0); Collection<Reference> surviverReferences = complexObjects.get(surviver); for (COSBase object : duplicateSet) { Collection<Reference> references = complexObjects.get(object); for (Reference reference : references) { reference.setTo(surviver); surviverReferences.add(reference); } complexObjects.remove(object); removedDuplicates++; } surviver.setDirect(false); } } return removedDuplicates; } boolean equals(COSBase a, COSBase b) { // Implementation of equals method if (a instanceof COSArray) { if (b instanceof COSArray) { COSArray aArray = (COSArray) a; COSArray bArray = (COSArray) b; if (aArray.size() == bArray.size()) { for (int i=0; i < aArray.size(); i++) { if (!resolve(aArray.get(i)).equals(resolve(bArray.get(i)))) return false; } return true; } } } else if (a instanceof COSDictionary) { if (b instanceof COSDictionary) { COSDictionary aDict = (COSDictionary) a; COSDictionary bDict = (COSDictionary) b; Set<COSName> keys = aDict.keySet(); if (keys.equals(bDict.keySet())) { for (COSName key : keys) { if (!resolve(aDict.getItem(key)).equals(bDict.getItem(key))) return false; } // In case of COSStreams we strictly speaking should // also compare the stream contents here. But apparently // their hashes coincide well enough for the original // hashing equality, so let's just assume... return true; } } } return false; } static COSBase resolve(COSBase object) { // Implementation of resolve method while (object instanceof COSObject) object = ((COSObject)object).getObject(); return object; } interface Reference { public COSBase getFrom(); public COSBase getTo(); public void setTo(COSBase to); } static class ArrayReference implements Reference { public ArrayReference(COSArray array, int index) { this.from = array; this.index = index; } @Override public COSBase getFrom() { return from; } @Override public COSBase getTo() { return resolve(from.get(index)); } @Override public void setTo(COSBase to) { from.set(index, to); } final COSArray from; final int index; } static class DictionaryReference implements Reference { public DictionaryReference(COSDictionary dictionary, COSName key) { this.from = dictionary; this.key = key; } @Override public COSBase getFrom() { return from; } @Override public COSBase getTo() { return resolve(from.getDictionaryObject(key)); } @Override public void setTo(COSBase to) { from.setItem(key, to); } final COSDictionary from; final COSName key; } static class HashOfCOSBase implements Comparable<HashOfCOSBase> { public HashOfCOSBase(COSBase object) throws IOException { this.object = object; this.hash = calculateHash(object); } int calculateHash(COSBase object) throws IOException { if (object instanceof COSArray) { int result = 1; for (COSBase member : (COSArray)object) result = 31 * result + member.hashCode(); return result; } else if (object instanceof COSDictionary) { int result = 3; for (Map.Entry<COSName, COSBase> entry : ((COSDictionary)object).entrySet()) result += entry.hashCode(); if (object instanceof COSStream) { try ( InputStream data = ((COSStream)object).createRawInputStream() ) { MessageDigest md = MessageDigest.getInstance("MD5"); byte[] buffer = new byte[8192]; int bytesRead = 0; while((bytesRead = data.read(buffer)) >= 0) md.update(buffer, 0, bytesRead); result = 31 * result + Arrays.hashCode(md.digest()); } catch (NoSuchAlgorithmException e) { throw new IOException(e); } } return result; } else { throw new IllegalArgumentException(String.format("Unknown complex COSBase type %s", object.getClass().getName())); } } final COSBase object; final int hash; @Override public int compareTo(HashOfCOSBase o) { int result = Integer.compare(hash, o.hash); if (result == 0) result = Integer.compare(hashCode(), o.hashCode()); return result; } } } {code}
>  
> However, it is not working for me. Can anyone have an idea to remove the duplicate embedded subsets of font in merging PDFs?
>  
>  
>  



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