1 files changed, 112 insertions, 0 deletions
diff --git a/libjava/gnu/gcj/tools/gc_analyze/SymbolLookup.java b/libjava/gnu/gcj/tools/gc_analyze/SymbolLookup.java
new file mode 100644
index 000000000..b3963d8cf
--- /dev/null
+++ b/libjava/gnu/gcj/tools/gc_analyze/SymbolLookup.java
@@ -0,0 +1,112 @@
+/* SymbolLookup.java -- Finds class names by analyzing memory.
+   Copyright (C) 2007  Free Software Foundation
+
+   This file is part of libgcj.
+
+   This software is copyrighted work licensed under the terms of the
+   Libgcj License.  Please consult the file "LIBGCJ_LICENSE" for
+   details.  */
+
+package gnu.gcj.tools.gc_analyze;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+
+class SymbolLookup
+{
+  MemoryMap memoryMap;
+
+  public SymbolLookup(BufferedReader reader,
+                      String rawFileName)
+    throws IOException
+  {
+    memoryMap = new MemoryMap(reader, rawFileName);
+  }
+
+  public String decodeUTF8(long address) throws IOException
+  {
+    return decodeUTF8(address, -1);
+  }
+  
+  public String decodeUTF8(long address, int limit) throws IOException
+  {
+    if (address == 0)
+      return null;
+
+    BytePtr utf8 = memoryMap.getBytePtr(address, 64);
+
+    if (utf8 == null)
+      return null;
+
+    int len = utf8.getShort(1);
+    int hash16 = utf8.getShort(0) & 0xffff;
+
+    if (len <= 0 || (limit > 0 && len > (limit - 4)))
+      return null;
+    
+    if (len > utf8.getsize() + 4)
+      utf8 = memoryMap.getBytePtr(address, len + 4);
+
+    if (utf8 == null)
+      return null;
+    
+    StringBuilder sb = new StringBuilder(len);
+    int pos = 4;
+    len += 4;
+    
+    while (pos < len)
+      {
+        int f = utf8.getByte(pos++);
+        if ((f & 0x80) == 0)
+          {
+            sb.append((char)f);
+          }
+        else if ((f & 0xe0) == 0xc0)
+          {
+            int s = utf8.getByte(pos++);
+            char c = (char)(((f & 0x1f) << 6) | (s & 0x80));
+            sb.append(c);
+          }
+        else if ((f & 0xe0) == 0xe0)
+          {
+            int s = utf8.getByte(pos++);
+            int t = utf8.getByte(pos++);
+            char c = (char)(((f & 0x0f) << 12)
+                            | ((s & 0x80) << 6) | (t & 0x80));
+            sb.append(c);
+          }
+        else 
+          break;  // Bad utf8
+      }
+    String rv = sb.toString();
+    if (hash16 == (rv.hashCode() & 0xffff))
+      return rv;
+    else
+      return null;
+  }
+
+  public String getSymbolViaVtable(long address) throws IOException
+  {
+    return memoryMap.getSymbol(address);
+  }
+
+  public String getSymbol(long address) throws IOException
+  {
+    String symbol = memoryMap.getSymbol(address);
+    if (null != symbol)
+      return symbol;
+    
+    BytePtr klass = memoryMap.getBytePtr(address, 3 * memoryMap.wordSize);
+    if (klass == null)
+      return null;
+    
+    long nameUTF8p = klass.getWord(2);
+    
+    return decodeUTF8(nameUTF8p);
+  }
+
+  BytePtr getBytePtr(long addr, int length) throws IOException
+  {
+    return memoryMap.getBytePtr(addr, length);
+  }
+}