Code drop from //branches/cupcake/...@124589
diff --git a/src/uniqstr.c b/src/uniqstr.c
new file mode 100644
index 0000000..8804a80
--- /dev/null
+++ b/src/uniqstr.c
@@ -0,0 +1,153 @@
+/* Keep a unique copy of strings.
+
+ Copyright (C) 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
+
+ This file is part of Bison, the GNU Compiler Compiler.
+
+ Bison is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 2, or (at your option)
+ any later version.
+
+ Bison is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with Bison; see the file COPYING. If not, write to
+ the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ Boston, MA 02110-1301, USA. */
+
+#include <config.h>
+#include "system.h"
+
+#include <error.h>
+#include <hash.h>
+#include <quotearg.h>
+
+#include "uniqstr.h"
+
+/*-----------------------.
+| A uniqstr hash table. |
+`-----------------------*/
+
+/* Initial capacity of uniqstr hash table. */
+#define HT_INITIAL_CAPACITY 257
+
+static struct hash_table *uniqstrs_table = NULL;
+
+/*-------------------------------------.
+| Create the uniqstr for S if needed. |
+`-------------------------------------*/
+
+uniqstr
+uniqstr_new (char const *str)
+{
+ uniqstr res = hash_lookup (uniqstrs_table, str);
+ if (!res)
+ {
+ /* First insertion in the hash. */
+ res = xstrdup (str);
+ hash_insert (uniqstrs_table, res);
+ }
+ return res;
+}
+
+
+/*------------------------------.
+| Abort if S is not a uniqstr. |
+`------------------------------*/
+
+void
+uniqstr_assert (char const *str)
+{
+ if (!hash_lookup (uniqstrs_table, str))
+ {
+ error (0, 0,
+ "not a uniqstr: %s", quotearg (str));
+ abort ();
+ }
+}
+
+
+/*--------------------.
+| Print the uniqstr. |
+`--------------------*/
+
+static inline bool
+uniqstr_print (uniqstr ustr)
+{
+ fprintf (stderr, "%s\n", ustr);
+ return true;
+}
+
+static bool
+uniqstr_print_processor (void *ustr, void *null ATTRIBUTE_UNUSED)
+{
+ return uniqstr_print (ustr);
+}
+
+
+/*-----------------------.
+| A uniqstr hash table. |
+`-----------------------*/
+
+static bool
+hash_compare_uniqstr (void const *m1, void const *m2)
+{
+ return strcmp (m1, m2) == 0;
+}
+
+static size_t
+hash_uniqstr (void const *m, size_t tablesize)
+{
+ return hash_string (m, tablesize);
+}
+
+/*----------------------------.
+| Create the uniqstrs table. |
+`----------------------------*/
+
+void
+uniqstrs_new (void)
+{
+ uniqstrs_table = hash_initialize (HT_INITIAL_CAPACITY,
+ NULL,
+ hash_uniqstr,
+ hash_compare_uniqstr,
+ free);
+}
+
+
+/*-------------------------------------.
+| Perform a task on all the uniqstrs. |
+`-------------------------------------*/
+
+static void
+uniqstrs_do (Hash_processor processor, void *processor_data)
+{
+ hash_do_for_each (uniqstrs_table, processor, processor_data);
+}
+
+
+/*-----------------.
+| Print them all. |
+`-----------------*/
+
+void
+uniqstrs_print (void)
+{
+ uniqstrs_do (uniqstr_print_processor, NULL);
+}
+
+
+/*--------------------.
+| Free the uniqstrs. |
+`--------------------*/
+
+void
+uniqstrs_free (void)
+{
+ hash_free (uniqstrs_table);
+}