support: Implement TEST_COMPARE_STRING

support/support_test_compare_string.c

@@ -0,0 +1,91 @@
+/* Check two strings for equality.
+   Copyright (C) 2018 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C 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.
+
+   The GNU C 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 the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <support/check.h>
+#include <support/support.h>
+#include <support/xmemstream.h>
+
+static void
+report_length (const char *what, const char *str, size_t length)
+{
+  if (str == NULL)
+    printf ("  %s string: NULL\n", what);
+  else
+    printf ("  %s string: %zu bytes\n", what, length);
+}
+
+static void
+report_string (const char *what, const unsigned char *blob,
+               size_t length, const char *expr)
+{
+  if (length > 0)
+    {
+      printf ("  %s (evaluated from %s):\n", what, expr);
+      char *quoted = support_quote_blob (blob, length);
+      printf ("      \"%s\"\n", quoted);
+      free (quoted);
+
+      fputs ("     ", stdout);
+      for (size_t i = 0; i < length; ++i)
+        printf (" %02X", blob[i]);
+      putc ('\n', stdout);
+    }
+}
+
+static size_t
+string_length_or_zero (const char *str)
+{
+  if (str == NULL)
+    return 0;
+  else
+    return strlen (str);
+}
+
+void
+support_test_compare_string (const char *left, const char *right,
+                             const char *file, int line,
+                             const char *left_expr, const char *right_expr)
+{
+  /* Two null pointers are accepted.  */
+  if (left == NULL && right == NULL)
+    return;
+
+  size_t left_length = string_length_or_zero (left);
+  size_t right_length = string_length_or_zero (right);
+
+  if (left_length != right_length || left == NULL || right == NULL
+      || memcmp (left, right, left_length) != 0)
+    {
+      support_record_failure ();
+      printf ("%s:%d: error: blob comparison failed\n", file, line);
+      if (left_length == right_length && right != NULL && left != NULL)
+        printf ("  string length: %lu bytes\n", left_length);
+      else
+        {
+          report_length ("left", left, left_length);
+          report_length ("right", right, right_length);
+        }
+      report_string ("left", (const unsigned char *) left,
+                     left_length, left_expr);
+      report_string ("right", (const unsigned char *) right,
+                     right_length, right_expr);
+    }
+}