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Add isEquivalentTo method to COSBase and COSObject #712

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45 changes: 45 additions & 0 deletions src/main/java/org/verapdf/cos/COSArray.java
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Original file line number Diff line number Diff line change
Expand Up @@ -189,6 +189,51 @@ private COSObject _at(final int i) {
return this.entries.get(i);
}

@Override
public boolean isEquivalentTo(Object o) {
if (this == o) return true;
if (o == null) return false;

if (o instanceof COSObject) {
return this.isEquivalentTo(((COSObject) o).get());
}
if (!(o instanceof COSArray)) return false;
List<COSBasePair> checkedObjects = new LinkedList<>();
return isEquivalentTo(o, checkedObjects);
}

@Override
boolean isEquivalentTo(Object o, List<COSBasePair> checkedObjects) {
if (this == o) return true;
if (o == null) return false;

if (o instanceof COSObject) {
return this.isEquivalentTo(((COSObject) o).get(), checkedObjects);
}
if (!(o instanceof COSArray)) return false;

COSArray that = (COSArray) o;
if (COSBasePair.listContainsPair(checkedObjects, this, that)) {
return true;
}
COSBasePair.addPairToList(checkedObjects, this, that);

if (this.size() != that.size()) return false;

for (int i = 0; i < this.size(); ++i) {
COSBase thisElem = this.at(i).getDirectBase();
COSBase thatElem = that.at(i).getDirectBase();

if (thisElem == null && thatElem == null) continue;
if (thisElem == null || thatElem == null) return false;

if (!thisElem.isEquivalentTo(thatElem, checkedObjects)) {
return false;
}
}
return true;
}

@Override
public boolean equals(Object obj) {
if (this == obj) {
Expand Down
6 changes: 6 additions & 0 deletions src/main/java/org/verapdf/cos/COSBase.java
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Expand Up @@ -140,6 +140,12 @@ public void setObjectKey(COSKey indirectKey) {

public abstract void mark();

public abstract boolean isEquivalentTo(Object obj);

boolean isEquivalentTo(Object o, List<COSBasePair> checkedObjects) {
return isEquivalentTo(o);
}
Comment on lines +145 to +147

@coderabbitai coderabbitai Bot Jul 30, 2026

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🩺 Stability & Availability | 🔴 Critical | 🏗️ Heavy lift

Preserve cycle-detection state across indirect dispatch.

The list-aware recursive callers pass checkedObjects, but the default and indirect implementations fall back to one-argument methods and restart traversal.

  • src/main/java/org/verapdf/cos/COSBase.java#L145-L147: do not discard the supplied list for recursive types.
  • src/main/java/org/verapdf/cos/COSIndirect.java#L483-L486: propagate the list when comparing indirect targets.
  • src/main/java/org/verapdf/cos/COSIndirect.java#L492-L497: propagate the list when comparing an indirect target with a COSObject.
📍 Affects 2 files
  • src/main/java/org/verapdf/cos/COSBase.java#L145-L147 (this comment)
  • src/main/java/org/verapdf/cos/COSIndirect.java#L483-L486
  • src/main/java/org/verapdf/cos/COSIndirect.java#L492-L497
🤖 Prompt for AI Agents 
Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@src/main/java/org/verapdf/cos/COSBase.java` around lines 145 - 147, Preserve
the supplied cycle-detection state during equivalent comparisons: update
COSBase.isEquivalentTo(Object, List<COSBasePair>) to dispatch recursive
comparisons with the existing checkedObjects list, and update both COSIndirect
comparison paths at src/main/java/org/verapdf/cos/COSIndirect.java lines 483-486
and 492-497 to pass that same list when comparing indirect targets, including
COSObject targets; do not restart traversal through one-argument methods.


boolean equals(Object obj, List<COSBasePair> checkedObjects) {
return this.equals(obj);
}
Expand Down
11 changes: 11 additions & 0 deletions src/main/java/org/verapdf/cos/COSBoolean.java
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Expand Up @@ -71,6 +71,17 @@ public boolean setBoolean(final boolean value) {
return true;
}

@Override
public boolean isEquivalentTo(Object o) {
if (this == o) return true;
if (!(o instanceof COSBoolean)) return false;

COSBoolean that = (COSBoolean) o;

return value == that.value;

}

public boolean get() {
return this.value;
}
Expand Down
64 changes: 64 additions & 0 deletions src/main/java/org/verapdf/cos/COSDictionary.java
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Expand Up @@ -299,6 +299,70 @@ public Collection<COSObject> getValues() {
return this.entries.values();
}

private Set<ASAtom> getNonNullKeySet() {
Set<ASAtom> nonNullKeys = new HashSet<>();
for (ASAtom key : getKeySet()) {
COSBase value = getKey(key).get(); // assume getKey returns a COSBase wrapper
if (value != null) {
nonNullKeys.add(key);
}
}
return nonNullKeys;
}

@Override
public boolean isEquivalentTo(Object o) {
if (this == o) return true;
if (o == null) return false;
if (o instanceof COSObject) {
return this.isEquivalentTo(((COSObject) o).get());
}
if (!(o instanceof COSDictionary)) return false;

List<COSBasePair> checkedObjects = new LinkedList<>();
return isEquivalentTo(o, checkedObjects);
}

/**
* Internal recursive comparison with cycle detection.
*/
boolean isEquivalentTo(Object o, List<COSBasePair> checkedObjects) {
if (this == o) return true;
if (o == null) return false;
if (o instanceof COSObject) {
return this.isEquivalentTo(((COSObject) o).get(), checkedObjects);
}
if (!(o instanceof COSDictionary)) return false;
Comment on lines +313 to +335

@coderabbitai coderabbitai Bot Jul 30, 2026

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🎯 Functional Correctness | 🟠 Major | ⚡ Quick win

🧩 Analysis chain

🏁 Script executed:

#!/bin/bash
# Confirm COSStream's superclass
rg -n 'class COSStream' -A2 --type=java

Repository: veraPDF/veraPDF-parser

Length of output: 160

🏁 Script executed:

#!/bin/bash
set -euo pipefail

printf 'Java files named COS*.java:\n'
fd '^COS.*\.java$' . || true

printf '\nSearch symbols:\n'
rg -n 'class COSStream|COSClassCOSStream|class COSDictionary|isEquivalentTo|function equivalent|byteContent|COSStream' -S --type=java . || true

Repository: veraPDF/veraPDF-parser

Length of output: 25872

🏁 Script executed:

#!/bin/bash
set -euo pipefail

printf 'COSDictionary isEquivalentTo and equals:\n'
sed -n '310,420p' src/main/java/org/verapdf/cos/COSDictionary.java | cat -n

printf '\nCOSStream isEquivalentTo and equals:\n'
sed -n '290,415p' src/main/java/org/verapdf/cos/COSStream.java | cat -n

printf '\nCOSDirect and COSBase relevant data members:\n'
sed -n '1,120p' src/main/java/org/verapdf/cos/COSDirect.java | cat -n
sed -n '260,315p' src/main/java/org/verapdf/cos/COSDirect.java | cat -n

Repository: veraPDF/veraPDF-parser

Length of output: 15896

Reject COSStream in COSDictionary.isEquivalentTo().

COSStream extends COSDictionary, so the current instanceof COSDictionary gate lets a plain dictionary pass equality with a stream whenever their key/values match, ignoring the stream data that COSStream.isEquivalentTo() compares. Use an explicit cross-type boundary, e.g. if (o.getClass() != COSDictionary.class && !(o instanceof COSObject)) return false;.

🤖 Prompt for AI Agents 
Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@src/main/java/org/verapdf/cos/COSDictionary.java` around lines 313 - 335,
Update both overloads of COSDictionary.isEquivalentTo, including the recursive
variant, to reject COSStream and any other COSDictionary subclass before
comparing entries; preserve COSObject unwrapping and allow only exact
COSDictionary instances through the dictionary comparison path.


COSDictionary that = (COSDictionary) o;

if (COSBasePair.listContainsPair(checkedObjects, this, that)) {
return true;
}
COSBasePair.addPairToList(checkedObjects, this, that);

Set<ASAtom> thisKeys = this.getNonNullKeySet();
Set<ASAtom> thatKeys = that.getNonNullKeySet();

if (!thisKeys.equals(thatKeys)) {
return false;
}

for (ASAtom key : thisKeys) {
COSBase thisVal = this.getKey(key).get();
COSBase thatVal = that.getKey(key).get();

if (thisVal == null && thatVal == null) continue;
if (thisVal == null || thatVal == null) return false;

if (!thisVal.isEquivalentTo(thatVal, checkedObjects)) {
return false;
}
}

return true;
}

@Override
public boolean equals(Object obj) {
if (this == obj) {
Expand Down
16 changes: 16 additions & 0 deletions src/main/java/org/verapdf/cos/COSIndirect.java
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Expand Up @@ -480,6 +480,22 @@ public void mark() {
}
}

@Override
public boolean isEquivalentTo(Object o) {
if (this == o) return true;

if (o instanceof COSIndirect) {
COSIndirect that = (COSIndirect) o;
return this.getDirect().isEquivalentTo(that.getDirect());
}

if (o instanceof COSObject) {
return this.getDirect().isEquivalentTo(o);
}

return false;
}

@Override
public boolean equals(Object o) {
if (this == o) return true;
Expand Down
23 changes: 23 additions & 0 deletions src/main/java/org/verapdf/cos/COSInteger.java
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Expand Up @@ -23,6 +23,8 @@
import org.verapdf.cos.visitor.ICOSVisitor;
import org.verapdf.cos.visitor.IVisitor;

import java.math.BigDecimal;

/**
* @author Timur Kamalov
*/
Expand Down Expand Up @@ -75,6 +77,22 @@ public boolean setReal(final double value) {
return true;
}

@Override
public boolean isEquivalentTo(Object o) {
if (this == o) return true;

if (o instanceof COSInteger) {
return this.value == ((COSInteger) o).value;
}

if (o instanceof COSReal) {
COSReal thatReal = (COSReal) o;
return BigDecimal.valueOf(this.value).compareTo(thatReal.getDecimalValue()) == 0;
}

return false;
}

public long get() {
return this.value;
}
Expand All @@ -97,4 +115,9 @@ public boolean equals(Object o) {
return value == that.value;

}

@Override
public BigDecimal getDecimalValue() {
return BigDecimal.valueOf(value);
}
}
14 changes: 14 additions & 0 deletions src/main/java/org/verapdf/cos/COSName.java
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Expand Up @@ -25,6 +25,7 @@
import org.verapdf.cos.visitor.IVisitor;

import java.nio.charset.StandardCharsets;
import java.util.Arrays;
import java.util.Objects;

/**
Expand Down Expand Up @@ -91,6 +92,19 @@ public boolean setName(final ASAtom value) {
return true;
}

@Override
public boolean isEquivalentTo(Object o) {
if (this == o) return true;
if (!(o instanceof COSName)) return false;

COSName that = (COSName) o;

byte[] thisBytes = this.getName().getValue().getBytes(StandardCharsets.ISO_8859_1);
byte[] thatBytes = that.getName().getValue().getBytes(StandardCharsets.ISO_8859_1);

return Arrays.equals(thisBytes, thatBytes);
}

Comment on lines +95 to +107

@coderabbitai coderabbitai Bot Jul 30, 2026

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🩺 Stability & Availability | 🟠 Major | ⚡ Quick win

Handle null ASAtom values before byte canonicalization.

COSName.construct(ASAtom) can store a null value, but this method dereferences getName().getValue() for both operands. Comparing null-valued names therefore throws an NPE; define null semantics before converting to bytes.

🧰 Tools
🪛 ast-grep (0.45.0)

[warning] 101-101: Use a randomly-generated IV
Context: byte[] thisBytes = this.getName().getValue().getBytes(StandardCharsets.ISO_8859_1);
Note: [CWE-329] Generation of Predictable IV with CBC Mode.

(random-iv)

[warning] 102-102: Use a randomly-generated IV
Context: byte[] thatBytes = that.getName().getValue().getBytes(StandardCharsets.ISO_8859_1);
Note: [CWE-329] Generation of Predictable IV with CBC Mode.

(random-iv)

🤖 Prompt for AI Agents 
Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@src/main/java/org/verapdf/cos/COSName.java` around lines 95 - 107, Update
COSName.isEquivalentTo to handle null ASAtom values before calling getValue() or
converting to bytes. Ensure two null values compare as equivalent, a null versus
non-null value returns false, and retain the existing byte comparison for
non-null values.

public ASAtom get() {
return value;
}
Expand Down
5 changes: 5 additions & 0 deletions src/main/java/org/verapdf/cos/COSNull.java
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Original file line number Diff line number Diff line change
Expand Up @@ -51,6 +51,11 @@ public Object accept(final ICOSVisitor visitor) {
return visitor.visitFromNull(this);
}

@Override
public boolean isEquivalentTo(Object o) {
return equals(o);
}

@Override
public boolean equals(Object o) {
if (this == o) return true;
Expand Down
4 changes: 4 additions & 0 deletions src/main/java/org/verapdf/cos/COSNumber.java
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Original file line number Diff line number Diff line change
Expand Up @@ -20,6 +20,8 @@
*/
package org.verapdf.cos;

import java.math.BigDecimal;

/**
* @author Timur Kamalov
*/
Expand All @@ -29,4 +31,6 @@ public COSNumber() {
super();
}

public abstract BigDecimal getDecimalValue();

}
13 changes: 13 additions & 0 deletions src/main/java/org/verapdf/cos/COSObject.java
View file
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Original file line number Diff line number Diff line change
Expand Up @@ -494,6 +494,19 @@ public void setIsHeaderFormatComplyPDFA(Boolean isHeaderFormatComplyPDFA) {
this.isHeaderFormatComplyPDFA = isHeaderFormatComplyPDFA;
}

public boolean isEquivalentTo(Object o) {
if (o == this) return true;
if (o instanceof COSObject) {
COSObject cosObject = (COSObject) o;
return base.isEquivalentTo(cosObject.base);
}

if (o instanceof COSIndirect) {
return base.isEquivalentTo(((COSIndirect) o).getDirect().base);
Comment on lines +497 to +505

@coderabbitai coderabbitai Bot Jul 30, 2026

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🩺 Stability & Availability | 🔴 Critical | ⚡ Quick win

Define behavior for empty and unresolved wrappers before dereferencing.

Both implementations assume a non-null underlying object, but the surrounding APIs permit empty COSObjects and nullable indirect children.

  • src/main/java/org/verapdf/cos/COSObject.java#L497-L505: handle null base values before delegation.
  • src/main/java/org/verapdf/cos/COSIndirect.java#L487-L494: handle null/unresolved getDirect() results before calling equivalence.
📍 Affects 2 files
  • src/main/java/org/verapdf/cos/COSObject.java#L497-L505 (this comment)
  • src/main/java/org/verapdf/cos/COSIndirect.java#L487-L494
🤖 Prompt for AI Agents 
Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@src/main/java/org/verapdf/cos/COSObject.java` around lines 497 - 505, Update
COSObject.isEquivalentTo in src/main/java/org/verapdf/cos/COSObject.java:497-505
to handle null base values before delegating, preserving equivalent
empty-wrapper behavior. Also update COSIndirect.isEquivalentTo in
src/main/java/org/verapdf/cos/COSIndirect.java:487-494 to check getDirect() for
null or unresolved results before accessing base, and define equivalence
consistently without dereferencing null objects.

}
return false;
}

@Override
public boolean equals(Object o) {
if (this == o) return true;
Expand Down
23 changes: 23 additions & 0 deletions src/main/java/org/verapdf/cos/COSReal.java
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Original file line number Diff line number Diff line change
Expand Up @@ -23,6 +23,7 @@
import org.verapdf.cos.visitor.ICOSVisitor;
import org.verapdf.cos.visitor.IVisitor;

import java.math.BigDecimal;
import java.text.DecimalFormat;
import java.text.DecimalFormatSymbols;

Expand All @@ -45,6 +46,11 @@ public class COSReal extends COSNumber {
protected COSReal() {
}

@Override
public BigDecimal getDecimalValue() {
return BigDecimal.valueOf(value);
}
Comment on lines +49 to +52

@coderabbitai coderabbitai Bot Jul 30, 2026

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🩺 Stability & Availability | 🟠 Major | ⚡ Quick win

🧩 Analysis chain

🏁 Script executed:

#!/bin/bash
set -euo pipefail

printf 'Files:\n'
fd -a 'COSReal.java|COSInteger.java' .

printf '\nCOSReal outline:\n'
ast-grep outline src/main/java/org/verapdf/cos/COSReal.java || true

printf '\nCOSInteger outline:\n'
ast-grep outline src/main/java/org/verapdf/cos/COSInteger.java || true

printf '\nRelevant code snippets:\n'
sed -n '1,140p' src/main/java/org/verapdf/cos/COSReal.java
printf '\n---\n'
sed -n '1,125p' src/main/java/org/verapdf/cos/COSInteger.java

printf '\nSearch for COSReal/COSInteger creation and getDecimalValue usage:\n'
rg -n "new COSReal|COSReal\.|getDecimalValue|compareTo.*getDecimalValue" src/main/java/org/verapdf/cos src/main/java -g '*.java' | head -200

printf '\nJava BigDecimal.valueOf behavior probe:\n'
python3 - <<'PY'
import math
values = [float('nan'), float('inf'), float('-inf'), 42.0]
for v in values:
    try:
        print(f"{v}: finite={math.isfinite(v)}")
        print(f"  Double.toString={float_repr(v)}")
    except NameError as e:
        print(f"{v}: finite={math.isfinite(v)}")
PY
printf '\nBehavior note: BigDecimal.valueOf(float/double) rejects NaN/infinity via Double.toString.\n'

Repository: veraPDF/veraPDF-parser

Length of output: 14662

🏁 Script executed:

#!/bin/bash
set -euo pipefail

provider=$(mvn help:evaluate -Dexpression=project.properties.pdfbox-provider -q -DforceStdout 2>/dev/null || true)
if [ -n "$provider" ]; then
    echo "current pdfbox-provider=${provider}"
else
    echo "pdfbox-provider not available"
fi

# Read the parser/token code around real-number construction without running repo code.
printf '\nPDFStreamParser token.real context:\n'
sed -n '120,190p' src/main/java/org/verapdf/parser/PDFStreamParser.java

printf '\nPostscript operators around division/log/sqrt context:\n'
sed -n '360,505p' src/main/java/org/verapdf/parser/postscript/PSOperator.java

printf '\nPDFStreamParser number token pattern references:\n'
rg -n "real|NUMBER|Double\\.|parseFloat" src/main/java/org/verapdf/parser src/main/java/org/verapdf/pd/function src/main/java/org/verapdf/pd/colors -g '*.java' | head -120

Repository: veraPDF/veraPDF-parser

Length of output: 11491

🌐 Web query:

Java BigDecimal.valueOf double NaN Infinity IllegalArgumentException source Double.toString

💡 Result:

In Java, the BigDecimal.valueOf(double) method explicitly throws a NumberFormatException (not an IllegalArgumentException) when the provided double is NaN (Not-a-Number), Double.POSITIVE_INFINITY, or Double.NEGATIVE_INFINITY [1][2][3][4]. The rationale for this behavior and its relationship to Double.toString(double) is as follows: 1. Method Behavior: The BigDecimal.valueOf(double) method is designed to be equivalent to calling new BigDecimal(Double.toString(val)) [1][4][5]. Since Double.toString() returns the strings "NaN", "Infinity", or "-Infinity" for non-finite values, and the BigDecimal(String) constructor cannot parse these specific strings into a numeric value, a NumberFormatException is thrown [1][3][6]. 2. Explicit Validation: Historically, this exception was a consequence of passing those strings to the BigDecimal(String) constructor [5]. However, modern implementations of BigDecimal.valueOf(double) (such as in recent OpenJDK versions) include explicit checks—such as !Double.isFinite(val)—to throw a NumberFormatException with a descriptive message ("Infinite or NaN") before any string conversion takes place [6]. 3. API Distinction: This behavior aligns with the standard design of BigDecimal as a class representing finite, arbitrary-precision signed decimal numbers, which inherently does not support non-finite floating-point concepts [2].

Citations:

Prevent finite-only real values from being exposed through BigDecimal conversion.

COSReal.setValue(double) also accepts NaN/infinity via set(), so getDecimalValue() will throw NumberFormatException when called from equivalent-comparison paths. Reject non-finite inputs in set / setReal / construct, or handle them explicitly before calling BigDecimal.valueOf(value) in getDecimalValue() and COSInteger.isEquivalentTo(...).

📍 Affects 2 files
  • src/main/java/org/verapdf/cos/COSReal.java#L49-L52 (this comment)
  • src/main/java/org/verapdf/cos/COSInteger.java#L88-L90
🤖 Prompt for AI Agents 
Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@src/main/java/org/verapdf/cos/COSReal.java` around lines 49 - 52, Ensure
non-finite values accepted by COSReal.setValue(double) cannot reach BigDecimal
conversion: update COSReal’s set/setReal/construct paths to reject NaN and
infinities, or explicitly handle them in COSReal.getDecimalValue() before
BigDecimal.valueOf(value). Also update COSInteger.isEquivalentTo(...) to handle
non-finite COSReal values without invoking BigDecimal conversion; apply the
changes in src/main/java/org/verapdf/cos/COSReal.java lines 49-52 and
src/main/java/org/verapdf/cos/COSInteger.java lines 88-90.


protected COSReal(final double value) {
this.value = value;
}
Expand Down Expand Up @@ -88,6 +94,23 @@ public boolean setReal(final double value) {
return true;
}

@Override
public boolean isEquivalentTo(Object o) {
if (this == o) return true;

if (o instanceof COSReal) {
COSReal thatReal = (COSReal) o;
return this.getDecimalValue().compareTo(thatReal.getDecimalValue()) == 0;
}

if (o instanceof COSInteger) {
COSInteger thatInt = (COSInteger) o;
return this.getDecimalValue().compareTo(thatInt.getDecimalValue()) == 0;
}

return false;
}

public double get() {
return this.value;
}
Expand Down
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