Scripted update of if statements

[yangtools.git] / yang / yang-data-impl / src / main / java / org / opendaylight / yangtools / yang / data / impl / codec / xml / RandomPrefix.java

diff --git a/yang/yang-data-impl/src/main/java/org/opendaylight/yangtools/yang/data/impl/codec/xml/RandomPrefix.java b/yang/yang-data-impl/src/main/java/org/opendaylight/yangtools/yang/data/impl/codec/xml/RandomPrefix.java
index 00fc7d708e03f0000428439865055e7afc58b6ce..125ac23eb86fd057551e821e76fa757b0f2a36bf 100644 (file)
--- a/yang/yang-data-impl/src/main/java/org/opendaylight/yangtools/yang/data/impl/codec/xml/RandomPrefix.java
+++ b/yang/yang-data-impl/src/main/java/org/opendaylight/yangtools/yang/data/impl/codec/xml/RandomPrefix.java
@@ -8,95 +8,84 @@
 package org.opendaylight.yangtools.yang.data.impl.codec.xml;
 
 import com.google.common.annotations.VisibleForTesting;
-import com.google.common.base.Strings;
+import com.google.common.base.Preconditions;
 import com.google.common.collect.BiMap;
 import com.google.common.collect.HashBiMap;
+
 import java.net.URI;
 import java.util.Map;
-import org.opendaylight.yangtools.yang.common.QName;
-
-final class RandomPrefix {
 
-    public static final char STARTING_CHAR = 'a';
-    public static final int CHARACTER_RANGE = 26;
-    public static final int PREFIX_MAX_LENGTH = 4;
+import javax.xml.XMLConstants;
+import javax.xml.namespace.NamespaceContext;
 
-    public static final int MAX_COUNTER_VALUE = (int) Math.pow(CHARACTER_RANGE, PREFIX_MAX_LENGTH);
-    private static final int STARTING_WITH_XML = decode("xml");
+class RandomPrefix {
+    // 32 characters, carefully chosen
+    private static final String LOOKUP = "abcdefghiknoprstABCDEFGHIKNOPRST";
+    private static final int MASK = 0x1f;
+    private static final int SHIFT = 5;
 
     private int counter = 0;
 
     // BiMap to make values lookup faster
     private final BiMap<URI, String> prefixes = HashBiMap.create();
+    private final NamespaceContext context;
 
-    Iterable<Map.Entry<URI, String>> getPrefixes() {
-        return prefixes.entrySet();
+    RandomPrefix() {
+        this.context = null;
     }
 
-    String encodeQName(final QName qname) {
-        return encodePrefix(qname) + ':' + qname.getLocalName();
+    RandomPrefix(final NamespaceContext context) {
+        this.context = Preconditions.checkNotNull(context);
+    }
+
+    Iterable<Map.Entry<URI, String>> getPrefixes() {
+        return prefixes.entrySet();
     }
 
-    String encodePrefix(final QName qname) {
-        String prefix = prefixes.get(qname.getNamespace());
+    String encodePrefix(final URI namespace) {
+        String prefix = prefixes.get(namespace);
         if (prefix != null) {
             return prefix;
         }
 
-        // Reuse prefix from QName if possible
-        final String qNamePrefix = qname.getPrefix();
-
-        if (!Strings.isNullOrEmpty(qNamePrefix) && !qNamePrefix.startsWith("xml") && !alreadyUsedPrefix(qNamePrefix)) {
-            prefix = qNamePrefix;
-        } else {
-
-            do {
-                // Skip values starting with xml (Expecting only 4 chars max since division is calculated only once)
-                while (counter == STARTING_WITH_XML
-                        || counter / CHARACTER_RANGE == STARTING_WITH_XML) {
-                    counter++;
-                }
-
-                // Reset in case of max prefix generated
-                if (counter >= MAX_COUNTER_VALUE) {
-                    counter = 0;
-                    prefixes.clear();
-                }
-
-                prefix = encode(counter);
-                counter++;
-            } while (alreadyUsedPrefix(prefix));
-        }
+        do {
+            prefix = encode(counter);
+            counter++;
+        } while (alreadyUsedPrefix(prefix));
 
-        prefixes.put(qname.getNamespace(), prefix);
+        prefixes.put(namespace, prefix);
         return prefix;
     }
 
     private boolean alreadyUsedPrefix(final String prefix) {
-        return prefixes.values().contains(prefix);
+        if (context == null) {
+            return false;
+        }
+
+        final String str = context.getNamespaceURI(prefix);
+        return !XMLConstants.NULL_NS_URI.equals(str);
     }
 
     @VisibleForTesting
-    static int decode(final String s) {
-        int num = 0;
-        for (final char ch : s.toCharArray()) {
-            num *= CHARACTER_RANGE;
-            num += (ch - STARTING_CHAR);
+    static int decode(final String str) {
+        int ret = 0;
+        for (char c : str.toCharArray()) {
+            int idx = LOOKUP.indexOf(c);
+            Preconditions.checkArgument(idx != -1, "Invalid string %s", str);
+            ret = (ret << SHIFT) + idx;
         }
-        return num;
+
+        return ret;
     }
 
     @VisibleForTesting
     static String encode(int num) {
-        if (num == 0) {
-            return "a";
-        }
-
         final StringBuilder sb = new StringBuilder();
-        while (num != 0) {
-            sb.append(((char) (num % CHARACTER_RANGE + STARTING_CHAR)));
-            num /= CHARACTER_RANGE;
-        }
+
+        do {
+            sb.append(LOOKUP.charAt(num & MASK));
+            num >>>= SHIFT;
+        } while (num != 0);
 
         return sb.reverse().toString();
     }