new vocab alien.cxx.demangle.libstdcxx: name demangling for gnu abi

extra/alien/cxx/demangle/libstdcxx/libstdcxx.factor

@@ -0,0 +1,39 @@
+! (c)2010 Joe Groff bsd license
+USING: alien alien.c-types alien.libraries alien.strings
+alien.syntax combinators destructors io.encodings.ascii kernel
+libc locals sequences system ;
+IN: alien.cxx.demangle.libstdcxx
+
+<<
+"libstdc++" {
+    { [ os macosx? ] [ "/usr/lib/libstdc++.6.0.9.dylib" ] }
+    { [ os unix? ] [ "/usr/lib/libstdc++.so" ] }
+} cond cdecl add-library
+>>
+
+LIBRARY: libstdc++
+
+FUNCTION: char* __cxa_demangle ( char* mangled_name, char* output_buffer, size_t* length, int* status ) ;
+
+ERROR: demangle-memory-allocation-failure ;
+ERROR: invalid-mangled-name name ;
+ERROR: invalid-demangle-args name ;
+
+: demangle-error ( name status -- )
+    {
+        {  0 [ drop ] }
+        { -1 [ drop demangle-memory-allocation-failure ] }
+        { -2 [ invalid-mangled-name ] }
+        { -3 [ invalid-demangle-args ] }
+    } case ;
+
+: mangled-name? ( name -- ? )
+    "_Z" head? ;
+
+:: demangle ( mangled-name -- c++-name )
+    0 <ulong> :> length
+    0 <int> :> status [
+        mangled-name ascii string>alien f length status __cxa_demangle &(free) :> demangled-buf
+        mangled-name status *int demangle-error
+        demangled-buf ascii alien>string
+    ] with-destructors ;