Add support of the /VE tag in OCMD

src/main/java/org/verapdf/as/ASAtom.java

@@ -66,6 +66,7 @@ public class ASAtom implements Comparable<ASAtom> {
     public static final ASAtom ALT = new ASAtom("Alt");
     public static final ASAtom ALTERNATE = new ASAtom("Alternate");
     public static final ASAtom ALTERNATES = new ASAtom("Alternates");
+    public static final ASAtom AND = new ASAtom("And");
     public static final ASAtom ANNOT = new ASAtom("Annot");
     public static final ASAtom ANNOTS = new ASAtom("Annots");
     public static final ASAtom ANTI_ALIAS = new ASAtom("AntiAlias");
@@ -402,6 +403,7 @@ public class ASAtom implements Comparable<ASAtom> {
     public static final ASAtom NON_EFONT_NO_WARN = new ASAtom("NonEFontNoWarn");
     public static final ASAtom NON_FULL_SCREEN_PAGE_MODE = new ASAtom("NonFullScreenPageMode");
     public static final ASAtom NONE = new ASAtom("None");
+    public static final ASAtom NOT = new ASAtom("Not");
     public static final ASAtom NOTE_TYPE = new ASAtom("NoteType");
     public static final ASAtom NORMAL = new ASAtom("Normal");
     public static final ASAtom NS = new ASAtom("NS");
@@ -426,6 +428,7 @@ public class ASAtom implements Comparable<ASAtom> {
     public static final ASAtom OPI = new ASAtom("OPI");
     public static final ASAtom OPM = new ASAtom("OPM");
     public static final ASAtom OPT = new ASAtom("Opt");
+    public static final ASAtom OR = new ASAtom("Or");
     public static final ASAtom ORDER = new ASAtom("Order");
     public static final ASAtom ORDERING = new ASAtom("Ordering");
     public static final ASAtom OS = new ASAtom("OS");
@@ -603,6 +606,7 @@ public class ASAtom implements Comparable<ASAtom> {
     public static final ASAtom USE_CMAP = new ASAtom("UseCMap");
     // V
     public static final ASAtom V = new ASAtom("V");
+    public static final ASAtom VE = new ASAtom("VE");
     public static final ASAtom VERISIGN_PPKVS = new ASAtom("VeriSign.PPKVS");
     public static final ASAtom VERSION = new ASAtom("Version");
     public static final ASAtom VERTICES = new ASAtom("Vertices");

src/main/java/org/verapdf/pd/optionalcontent/PDOCMDDictionary.java

@@ -1,12 +1,14 @@
 package org.verapdf.pd.optionalcontent;
 
 import org.verapdf.as.ASAtom;
-import org.verapdf.cos.COSArray;
-import org.verapdf.cos.COSBase;
-import org.verapdf.cos.COSObjType;
-import org.verapdf.cos.COSObject;
+import org.verapdf.cos.*;
+
+import java.util.logging.Level;
+import java.util.logging.Logger;
 
 public class PDOCMDDictionary {
+    private static final Logger LOGGER = Logger.getLogger(PDOCMDDictionary.class.getCanonicalName());
+
     public static boolean isVisibleOCMDByP(COSBase property, PDOptionalContentProperties optProperties) {
         COSObject ocgProperty = property.getKey(ASAtom.OCGS);
         if (ocgProperty == null || ocgProperty.getType() != COSObjType.COS_ARRAY) {
@@ -34,4 +36,67 @@ public static boolean isVisibleOCMDByP(COSBase property, PDOptionalContentProper
         }
         return ASAtom.ALL_OFF.equals(pValue) || ASAtom.ALL_ON.equals(pValue);
     }
+
+    public static boolean isVisibleOCMD(COSBase property, PDOptionalContentProperties optProperties) {
+        COSObject veProperty = property.getKey(ASAtom.VE);
+        if (veProperty != null && veProperty.getType() == COSObjType.COS_ARRAY) {
+            COSArray veArray = (COSArray) veProperty.getDirectBase();
+            return evaluateVE(veArray, optProperties);
+        }
+
+        return isVisibleOCMDByP(property, optProperties);
+    }
+
+    private static boolean evaluateVE(COSArray expr, PDOptionalContentProperties optProperties) {
+        if (expr.size() == 0) {
+            return true;
+        }
+
+        COSBase first = expr.at(0).getDirectBase();
+
+        if (first instanceof COSName) {
+            ASAtom operator = first.getName();
+
+            if (ASAtom.OR.equals(operator)) {
+                for (int i = 1; i < expr.size(); i++) {
+                    if (evaluateOperandOfVE(expr.at(i).getDirectBase(), optProperties)) {
+                        return true;
+                    }
+                }
+                return false;
+            } else if (ASAtom.AND.equals(operator)) {
+                for (int i = 1; i < expr.size(); i++) {
+                    if (!evaluateOperandOfVE(expr.at(i).getDirectBase(), optProperties)) {
+                        return false;
+                    }
+                }
+                return true;
+            } else if (ASAtom.NOT.equals(operator)) {
+                if (expr.size() != 2) {
+                    LOGGER.log(Level.WARNING, "/Not operator should have only 1 argument in VE array");
+                    return true;
+                }
+                return !evaluateOperandOfVE(expr.at(1).getDirectBase(), optProperties);
+            }
+            LOGGER.log(Level.WARNING, String.format("First element of VE array has value %s instead of /And, /Or or /Not", operator));
+        } else {
+            LOGGER.log(Level.WARNING, "First element of VE array should have type name");
+        }
+
+        return true;
+    }
+
+
+    private static boolean evaluateOperandOfVE(COSBase operand, PDOptionalContentProperties optProperties) {
+        if (operand instanceof COSArray) {
+            return evaluateVE((COSArray) operand, optProperties);
+
+        } else if (operand instanceof COSDictionary) {
+            COSDictionary dict = (COSDictionary) operand;
+            String name = dict.getStringKey(ASAtom.NAME);
+            return optProperties.isVisibleLayer(name);
+        }
+
+        return true;
+    }
 }