Provide a real std::string hash, not just a forward declaration for something

that doesn't exist.

TBR=nealsid

Code review URL: http://groups.google.com/group/google-breakpad-dev/browse_thread/thread/292f9ed79dfdbdde


git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@391 4c0a9323-5329-0410-9bdc-e9ce6186880e

src/common/mac/dwarf/functioninfo.cc

@@ -39,14 +39,25 @@
 #include "common/mac/dwarf/bytereader.h"
 
 
-namespace __gnu_cxx 
-{
-  template<> 
-    struct hash<std::string> 
-    {
-      size_t operator()(const std::string& k) const;
-    };
-}
+namespace __gnu_cxx {
+
+// Implement a string hash function so that std::string can be used as a key
+// in STL maps and sets.  The hash algorithm comes from the GNU C++ library,
+// in <tr1/functional>.  It is duplicated here because GCC versions prior to
+// 4.3.2 are unable to compile <tr1/functional> when RTTI is disabled, as it
+// may be in this code.
+
+template<>
+struct hash<std::string> {
+  std::size_t operator()(const std::string& s) const {
+    std::size_t result = 0;
+    for (std::string::const_iterator i = s.begin(); i != s.end(); ++i)
+      result = (result * 131) + *i;
+    return result;
+  }
+};
+
+}  // namespace __gnu_cxx
 
 
 namespace dwarf2reader {