+/* This file is part of the Lexical::Types Perl module.
+ * See http://search.cpan.org/dist/Lexical-Types/ */
+
+/* This is a pointer table implementation essentially copied from the ptr_table
+ * implementation in perl's sv.c, except that it has been modified to use memory
+ * shared across threads.
+ * Copyright goes to the original authors, bug reports to me. */
+
+/* This header is designed to be included several times with different
+ * definitions for PTABLE_NAME and PTABLE_VAL_FREE(). */
+
+#undef VOID2
+#ifdef __cplusplus
+# define VOID2(T, P) static_cast<T>(P)
+#else
+# define VOID2(T, P) (P)
+#endif
+
+#undef pPTBLMS
+#undef pPTBLMS_
+#undef aPTBLMS
+#undef aPTBLMS_
+
+/* Context for PerlMemShared_* functions */
+
+#ifdef PERL_IMPLICIT_SYS
+# define pPTBLMS pTHX
+# define pPTBLMS_ pTHX_
+# define aPTBLMS aTHX
+# define aPTBLMS_ aTHX_
+#else
+# define pPTBLMS void
+# define pPTBLMS_
+# define aPTBLMS
+# define aPTBLMS_
+#endif
+
+#ifndef pPTBL
+# define pPTBL pPTBLMS
+#endif
+#ifndef pPTBL_
+# define pPTBL_ pPTBLMS_
+#endif
+#ifndef aPTBL
+# define aPTBL aPTBLMS
+#endif
+#ifndef aPTBL_
+# define aPTBL_ aPTBLMS_
+#endif
+
+#ifndef PTABLE_NAME
+# define PTABLE_NAME ptable
+#endif
+
+#ifndef PTABLE_VAL_FREE
+# define PTABLE_VAL_FREE(V)
+#endif
+
+#ifndef PTABLE_JOIN
+# define PTABLE_PASTE(A, B) A ## B
+# define PTABLE_JOIN(A, B) PTABLE_PASTE(A, B)
+#endif
+
+#ifndef PTABLE_PREFIX
+# define PTABLE_PREFIX(X) PTABLE_JOIN(PTABLE_NAME, X)
+#endif
+
+#ifndef ptable_ent