Fix reported segfault on full-range alpha map

* tests/Makefile.am, +tests/test_byte_alpha.c:
  - Add test case
* datrie/alpha-map.c (alpha_map_recalc_work_area()):
  - Redeclare trie_last as TrieIndex, to prevent overflow.

Thanks Xiao Wang for the report, and @nevermatch for the analysis.

Closes: #6
#6

ChangeLog

@@ -1,3 +1,17 @@
+2018-04-21  Theppitak Karoonboonyanan  <[email protected]>
+
+	Fix reported segfault on full-range alpha map
+
+	* tests/Makefile.am, +tests/test_byte_alpha.c:
+	  - Add test case
+	* datrie/alpha-map.c (alpha_map_recalc_work_area()):
+	  - Redeclare trie_last as TrieIndex, to prevent overflow.
+
+	Thanks Xiao Wang for the report, and @nevermatch for the analysis.
+
+	Closes: #6
+	https://github.com/tlwg/libdatrie/issues/6
+
 2018-03-29  Theppitak Karoonboonyanan  <[email protected]>
 
 	Fix trie_state_get_data() at a prefix key

datrie/alpha-map.c

@@ -417,7 +417,7 @@ alpha_map_recalc_work_area (AlphaMap *alpha_map)
         const AlphaChar alpha_begin = range->begin;
         int       n_cells, i;
         AlphaChar a;
-        TrieChar  trie_last = 0;
+        TrieIndex trie_last = 0;
         TrieChar  tc;
 
         /* reconstruct alpha-to-trie map */

tests/Makefile.am

@@ -10,6 +10,7 @@ TESTS = \
 	test_nonalpha \
 	test_null_trie \
 	test_term_state \
+	test_byte_alpha \
 	$(NULL)
 
 check_PROGRAMS = \
@@ -20,6 +21,7 @@ check_PROGRAMS = \
 	test_nonalpha \
 	test_null_trie \
 	test_term_state \
+	test_byte_alpha \
 	$(NULL)
 
 noinst_HEADERS = \
@@ -68,3 +70,9 @@ test_term_state_SOURCES = \
 	$(NULL)
 test_term_state_LDADD = $(top_builddir)/datrie/libdatrie.la
 
+test_byte_alpha_SOURCES = \
+	test_byte_alpha.c \
+	utils.c \
+	$(NULL)
+test_byte_alpha_LDADD = $(top_builddir)/datrie/libdatrie.la
+

tests/test_byte_alpha.c

@@ -0,0 +1,94 @@
+/* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * libdatrie - Double-Array Trie Library
+ * Copyright (C) 2018  Theppitak Karoonboonyanan <[email protected]>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * test_byte_alpha.c - Test byte stream (full-range 0..255) alpha map
+ * Created: 2018-04-21
+ * Author:  Theppitak Karoonboonyanan <[email protected]>
+ *          Based on test case in issue #6
+ *          https://github.com/tlwg/libdatrie/issues/6
+ */
+
+#include <datrie/trie.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#define TEST_DATA 255
+int
+main ()
+{
+    AlphaMap    *alpha_map;
+    Trie        *test_trie;
+    AlphaChar    key[3];
+    TrieData     data;
+
+    msg_step ("Preparing alpha map");
+    alpha_map = alpha_map_new ();
+    if (!alpha_map) {
+        printf ("Fail to allocate alpha map\n");
+        goto err_alpha_map_not_created;
+    }
+    if (alpha_map_add_range (alpha_map, 0x00, 0xff) != 0) {
+        printf ("Fail to add full alpha map range\n");
+        goto err_alpha_map_created;
+    }
+
+    msg_step ("Preparing trie");
+    test_trie = trie_new (alpha_map);
+    alpha_map_free (alpha_map);
+    if (!test_trie) {
+        printf ("Fail to create test trie\n");
+        goto err_alpha_map_created;
+    }
+
+    msg_step ("Storing key to test trie");
+    key[0] = 0xff;
+    key[1] = 0xff;
+    key[2] = 0;
+    if (!trie_store (test_trie, key, TEST_DATA)) {
+        printf ("Fail to store key to test trie\n");
+        goto err_trie_created;
+    }
+
+    msg_step ("Retrieving data from test trie");
+    if (!trie_retrieve (test_trie, key, &data)) {
+        printf ("Fail to retrieve key from test trie\n");
+        goto err_trie_created;
+    }
+    if (TEST_DATA != data) {
+        printf ("Retrieved data = %d, not %d\n", data, TEST_DATA);
+        goto err_trie_created;
+    }
+
+    msg_step ("Freeing test trie");
+    trie_free (test_trie);
+    return 0;
+
+err_trie_created:
+    trie_free (test_trie);
+err_alpha_map_created:
+    alpha_map_free (alpha_map);
+err_alpha_map_not_created:
+    return 1;
+}
+
+/*
+vi:ts=4:ai:expandtab
+*/