Add struct scratch_buffer and its internal helper functions

These will be used from NSS modules, so they have to be exported.

malloc/tst-scratch_buffer.c

@@ -0,0 +1,155 @@
+/*
+   Copyright (C) 2015 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 <scratch_buffer.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <string.h>
+
+static bool
+unchanged_array_size (struct scratch_buffer *buf, size_t a, size_t b)
+{
+  size_t old_length = buf->length;
+  if (!scratch_buffer_set_array_size (buf, a, b))
+    {
+      printf ("scratch_buffer_set_array_size failed: %zu %zu\n",
+	      a, b);
+      return false;
+    }
+  if (old_length != buf->length)
+    {
+      printf ("scratch_buffer_set_array_size did not preserve size: %zu %zu\n",
+	      a, b);
+      return false;
+    }
+  return true;
+}
+
+static bool
+array_size_must_fail (size_t a, size_t b)
+{
+  for (int pass = 0; pass < 2; ++pass)
+    {
+      struct scratch_buffer buf;
+      scratch_buffer_init (&buf);
+      if (pass > 0)
+	if (!scratch_buffer_grow (&buf))
+	  {
+	    printf ("scratch_buffer_grow in array_size_must_fail failed\n");
+	    return false;
+	  }
+      if (scratch_buffer_set_array_size (&buf, a, b))
+	{
+	  printf ("scratch_buffer_set_array_size passed: %d %zu %zu\n",
+		  pass, a, b);
+	  return false;
+	}
+      if (buf.data != buf.__space)
+	{
+	  printf ("scratch_buffer_set_array_size did not free: %d %zu %zu\n",
+		  pass, a, b);
+	  return false;
+	}
+    }
+  return true;
+}
+
+static int
+do_test (void)
+{
+  {
+    struct scratch_buffer buf;
+    scratch_buffer_init (&buf);
+    memset (buf.data, ' ', buf.length);
+    scratch_buffer_free (&buf);
+  }
+  {
+    struct scratch_buffer buf;
+    scratch_buffer_init (&buf);
+    memset (buf.data, ' ', buf.length);
+    size_t old_length = buf.length;
+    scratch_buffer_grow (&buf);
+    if (buf.length <= old_length)
+      {
+	printf ("scratch_buffer_grow did not enlarge buffer\n");
+	return 1;
+      }
+    memset (buf.data, ' ', buf.length);
+    scratch_buffer_free (&buf);
+  }
+  {
+    struct scratch_buffer buf;
+    scratch_buffer_init (&buf);
+    memset (buf.data, '@', buf.length);
+    strcpy (buf.data, "prefix");
+    size_t old_length = buf.length;
+    scratch_buffer_grow_preserve (&buf);
+    if (buf.length <= old_length)
+      {
+	printf ("scratch_buffer_grow_preserve did not enlarge buffer\n");
+	return 1;
+      }
+    if (strcmp (buf.data, "prefix") != 0)
+      {
+	printf ("scratch_buffer_grow_preserve did not copy buffer\n");
+	return 1;
+      }
+    for (unsigned i = 7; i < old_length; ++i)
+      if (((char *)buf.data)[i] != '@')
+	{
+	  printf ("scratch_buffer_grow_preserve did not copy buffer (%u)\n",
+		  i);
+	  return 1;
+	}
+    scratch_buffer_free (&buf);
+  }
+  {
+    struct scratch_buffer buf;
+    scratch_buffer_init (&buf);
+    for (int pass = 0; pass < 4; ++pass)
+      {
+	if (!(unchanged_array_size (&buf, 0, 0)
+	      && unchanged_array_size (&buf, 1, 0)
+	      && unchanged_array_size (&buf, 0, 1)
+	      && unchanged_array_size (&buf, -1, 0)
+	      && unchanged_array_size (&buf, 0, -1)
+	      && unchanged_array_size (&buf, 1ULL << 16, 0)
+	      && unchanged_array_size (&buf, 0, 1ULL << 16)
+	      && unchanged_array_size (&buf, 1ULL << 32, 0)
+	      && unchanged_array_size (&buf, 0, 1ULL << 32)))
+	  return 1;
+	if (!scratch_buffer_grow (&buf))
+	  {
+	    printf ("scratch_buffer_grow_failed (pass %d)\n", pass);
+	  }
+      }
+    scratch_buffer_free (&buf);
+  }
+  {
+    if (!(array_size_must_fail (-1, 1)
+	  && array_size_must_fail (-1, -1)
+	  && array_size_must_fail (1, -1)
+	  && array_size_must_fail (((size_t)-1) / 4, 4)
+	  && array_size_must_fail (4, ((size_t)-1) / 4)))
+	return 1;
+  }
+  return 0;
+}
+
+#define TEST_FUNCTION do_test ()
+#include "../test-skeleton.c"