2002/03/21 01:19:33

[org.ibex.core.git] / src / org / mozilla / javascript / Label.java

diff --git a/src/org/mozilla/javascript/Label.java b/src/org/mozilla/javascript/Label.java
new file mode 100644 (file)
index 0000000..8e42d46
--- /dev/null
+++ b/src/org/mozilla/javascript/Label.java
@@ -0,0 +1,106 @@
+/* -*- Mode: java; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-\r
+ *\r
+ * The contents of this file are subject to the Netscape Public\r
+ * License Version 1.1 (the "License"); you may not use this file\r
+ * except in compliance with the License. You may obtain a copy of\r
+ * the License at http://www.mozilla.org/NPL/\r
+ *\r
+ * Software distributed under the License is distributed on an "AS\r
+ * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express oqr\r
+ * implied. See the License for the specific language governing\r
+ * rights and limitations under the License.\r
+ *\r
+ * The Original Code is Rhino code, released\r
+ * May 6, 1999.\r
+ *\r
+ * The Initial Developer of the Original Code is Netscape\r
+ * Communications Corporation.  Portions created by Netscape are\r
+ * Copyright (C) 1997-1999 Netscape Communications Corporation. All\r
+ * Rights Reserved.\r
+ *\r
+ * Contributor(s): \r
+ * Roger Lawrence\r
+ *\r
+ * Alternatively, the contents of this file may be used under the\r
+ * terms of the GNU Public License (the "GPL"), in which case the\r
+ * provisions of the GPL are applicable instead of those above.\r
+ * If you wish to allow use of your version of this file only\r
+ * under the terms of the GPL and not to allow others to use your\r
+ * version of this file under the NPL, indicate your decision by\r
+ * deleting the provisions above and replace them with the notice\r
+ * and other provisions required by the GPL.  If you do not delete\r
+ * the provisions above, a recipient may use your version of this\r
+ * file under either the NPL or the GPL.\r
+ */\r
+\r
+package org.mozilla.javascript;\r
+\r
+public class Label {\r
+    \r
+    private static final int FIXUPTABLE_SIZE = 8;\r
+\r
+    private static final boolean DEBUG = true;\r
+\r
+    public Label()\r
+    {\r
+        itsPC = -1;\r
+    }\r
+\r
+    public short getPC()\r
+    {\r
+        return itsPC;\r
+    }\r
+    \r
+    public void fixGotos(byte theCodeBuffer[])\r
+    {\r
+        if (DEBUG) {\r
+            if ((itsPC == -1) && (itsFixupTable != null))\r
+                throw new RuntimeException("Unlocated label");\r
+        }\r
+        if (itsFixupTable != null) {\r
+            for (int i = 0; i < itsFixupTableTop; i++) {\r
+                int fixupSite = itsFixupTable[i];\r
+                // -1 to get delta from instruction start\r
+                short offset = (short)(itsPC - (fixupSite - 1));\r
+                theCodeBuffer[fixupSite++] = (byte)(offset >> 8);\r
+                theCodeBuffer[fixupSite] = (byte)offset;\r
+            }\r
+        }\r
+        itsFixupTable = null;\r
+    }\r
+\r
+    public void setPC(short thePC)\r
+    {\r
+        if (DEBUG) {\r
+            if ((itsPC != -1) && (itsPC != thePC)) {\r
+                throw new RuntimeException("Duplicate label");\r
+            }\r
+        }\r
+\r
+        itsPC = thePC;\r
+    }\r
+\r
+    public void addFixup(int fixupSite)\r
+    {\r
+        if (itsFixupTable == null) {\r
+            itsFixupTableTop = 1;\r
+            itsFixupTable = new int[FIXUPTABLE_SIZE];\r
+            itsFixupTable[0] = fixupSite;            \r
+        }\r
+        else {\r
+            if (itsFixupTableTop == itsFixupTable.length) {\r
+                int oldLength = itsFixupTable.length;\r
+                int newTable[] = new int[oldLength + FIXUPTABLE_SIZE];\r
+                System.arraycopy(itsFixupTable, 0, newTable, 0, oldLength);\r
+                itsFixupTable = newTable;\r
+            }\r
+            itsFixupTable[itsFixupTableTop++] = fixupSite;            \r
+        }\r
+    }\r
+\r
+    private short itsPC = -1;\r
+    private int itsFixupTable[];\r
+    private int itsFixupTableTop;\r
+\r
+}\r
+\r