[glib: 14/16] gutf8: Add a g_utf8_validate_len() function

[Philip Withnall <pwithnall src gnome org>]

commit 7a4025cac1d0d29b086e30a7d5f7a98ffe3e9df5
Author: Philip Withnall <withnall endlessm com>
Date:   Mon Oct 1 19:52:14 2018 +0100

    gutf8: Add a g_utf8_validate_len() function
    
    This is a variant of g_utf8_validate() which requires the length to be
    specified, thereby allowing string lengths up to G_MAXSIZE rather than
    just G_MAXSSIZE.
    
    Signed-off-by: Philip Withnall <withnall endlessm com>

 docs/reference/glib/glib-sections.txt |  1 +
 glib/gunicode.h                       |  4 ++++
 glib/gutf8.c                          | 42 ++++++++++++++++++++++++++++++-----
 glib/tests/utf8-validate.c            | 15 +++++++++----
 4 files changed, 53 insertions(+), 9 deletions(-)
---
diff --git a/docs/reference/glib/glib-sections.txt b/docs/reference/glib/glib-sections.txt
index f88d6b53b..d875f9a3a 100644
--- a/docs/reference/glib/glib-sections.txt
+++ b/docs/reference/glib/glib-sections.txt
@@ -2964,6 +2964,7 @@ g_utf8_strrchr
 g_utf8_strreverse
 g_utf8_substring
 g_utf8_validate
+g_utf8_validate_len
 g_utf8_make_valid
 
 <SUBSECTION>
diff --git a/glib/gunicode.h b/glib/gunicode.h
index 481bc5212..36f841b9d 100644
--- a/glib/gunicode.h
+++ b/glib/gunicode.h
@@ -847,6 +847,10 @@ GLIB_AVAILABLE_IN_ALL
 gboolean g_utf8_validate (const gchar  *str,
                           gssize        max_len,
                           const gchar **end);
+GLIB_AVAILABLE_IN_2_60
+gboolean g_utf8_validate_len (const gchar  *str,
+                              gsize         max_len,
+                              const gchar **end);
 
 GLIB_AVAILABLE_IN_ALL
 gchar *g_utf8_strup   (const gchar *str,
diff --git a/glib/gutf8.c b/glib/gutf8.c
index a0fb16370..291534fc8 100644
--- a/glib/gutf8.c
+++ b/glib/gutf8.c
@@ -1669,16 +1669,48 @@ g_utf8_validate (const char   *str,
 {
   const gchar *p;
 
-  if (max_len < 0)
-    p = fast_validate (str);
+  if (max_len >= 0)
+    return g_utf8_validate_len (str, max_len, end);
+
+  p = fast_validate (str);
+
+  if (end)
+    *end = p;
+
+  if (*p != '\0')
+    return FALSE;
   else
-    p = fast_validate_len (str, max_len);
+    return TRUE;
+}
+
+/**
+ * g_utf8_validate_len:
+ * @str: (array length=max_len) (element-type guint8): a pointer to character data
+ * @max_len: max bytes to validate
+ * @end: (out) (optional) (transfer none): return location for end of valid data
+ *
+ * Validates UTF-8 encoded text.
+ *
+ * As with g_utf8_validate(), but @max_len must be set, and hence this function
+ * will always return %FALSE if any of the bytes of @str are nul.
+ *
+ * Returns: %TRUE if the text was valid UTF-8
+ * Since: 2.60
+ */
+gboolean
+g_utf8_validate_len (const char   *str,
+                     gsize         max_len,
+                     const gchar **end)
+
+{
+  const gchar *p;
+
+  p = fast_validate_len (str, max_len);
 
   if (end)
     *end = p;
 
-  if ((max_len >= 0 && p != str + max_len) ||
-      (max_len < 0 && *p != '\0'))
+  if (p != str + max_len)
     return FALSE;
   else
     return TRUE;
diff --git a/glib/tests/utf8-validate.c b/glib/tests/utf8-validate.c
index 1609bde34..5806b29a0 100644
--- a/glib/tests/utf8-validate.c
+++ b/glib/tests/utf8-validate.c
@@ -280,15 +280,22 @@ do_test (gconstpointer d)
 
   result = g_utf8_validate (test->text, test->max_len, &end);
 
-  g_assert (result == test->valid);
-  g_assert (end - test->text == test->offset);
+  g_assert_true (result == test->valid);
+  g_assert_cmpint (end - test->text, ==, test->offset);
 
   if (test->max_len < 0)
     {
       result = g_utf8_validate (test->text, strlen (test->text), &end);
 
-      g_assert (result == test->valid);
-      g_assert (end - test->text == test->offset);
+      g_assert_true (result == test->valid);
+      g_assert_cmpint (end - test->text, ==, test->offset);
+    }
+  else
+    {
+      result = g_utf8_validate_len (test->text, test->max_len, &end);
+
+      g_assert_true (result == test->valid);
+      g_assert_cmpint (end - test->text, ==, test->offset);
     }
 }