Unit tests for g_utf8_pointer_to_offset and g_utf8_offset_to_pointer.

2005-11-17  Matthias Clasen  <mclasen@redhat.com>

	* tests/Makefile.am:
	* tests/utf8-pointer.c: Unit tests for g_utf8_pointer_to_offset
	and g_utf8_offset_to_pointer.

	* glib/gutf8.c (g_utf8_pointer_to_offset)
	(g_utf8_offset_to_pointer): Handle negative offsets, and use
	"stutter stepping" for going backwards. (#320638, Larry
	Ewing)

diff --git a/ChangeLog b/ChangeLog
index c6e93d6..ba16472 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,14 @@
 2005-11-17  Matthias Clasen  <mclasen@redhat.com>
 
+       * tests/Makefile.am:
+       * tests/utf8-pointer.c: Unit tests for g_utf8_pointer_to_offset
+       and g_utf8_offset_to_pointer.
+
+       * glib/gutf8.c (g_utf8_pointer_to_offset) 
+       (g_utf8_offset_to_pointer): Handle negative offsets, and use
+       "stutter stepping" for going backwards. (#320638, Larry
+       Ewing)
+
        * glib/gbacktrace.c:
        * glib/gdate.c:
        * glib/gthread.c: const correctness fixes, found

diff --git a/ChangeLog.pre-2-10 b/ChangeLog.pre-2-10
index c6e93d6..ba16472 100644 (file)
--- a/ChangeLog.pre-2-10
+++ b/ChangeLog.pre-2-10
@@ -1,5 +1,14 @@
 2005-11-17  Matthias Clasen  <mclasen@redhat.com>
 
+       * tests/Makefile.am:
+       * tests/utf8-pointer.c: Unit tests for g_utf8_pointer_to_offset
+       and g_utf8_offset_to_pointer.
+
+       * glib/gutf8.c (g_utf8_pointer_to_offset) 
+       (g_utf8_offset_to_pointer): Handle negative offsets, and use
+       "stutter stepping" for going backwards. (#320638, Larry
+       Ewing)
+
        * glib/gbacktrace.c:
        * glib/gdate.c:
        * glib/gthread.c: const correctness fixes, found

diff --git a/ChangeLog.pre-2-12 b/ChangeLog.pre-2-12
index c6e93d6..ba16472 100644 (file)
--- a/ChangeLog.pre-2-12
+++ b/ChangeLog.pre-2-12
@@ -1,5 +1,14 @@
 2005-11-17  Matthias Clasen  <mclasen@redhat.com>
 
+       * tests/Makefile.am:
+       * tests/utf8-pointer.c: Unit tests for g_utf8_pointer_to_offset
+       and g_utf8_offset_to_pointer.
+
+       * glib/gutf8.c (g_utf8_pointer_to_offset) 
+       (g_utf8_offset_to_pointer): Handle negative offsets, and use
+       "stutter stepping" for going backwards. (#320638, Larry
+       Ewing)
+
        * glib/gbacktrace.c:
        * glib/gdate.c:
        * glib/gthread.c: const correctness fixes, found

diff --git a/glib/gutf8.c b/glib/gutf8.c
index 612264e..4f7d486 100644 (file)
--- a/glib/gutf8.c
+++ b/glib/gutf8.c
@@ -284,6 +284,9 @@ g_utf8_get_char (const gchar *p)
  * Converts from an integer character offset to a pointer to a position
  * within the string.
  * 
+ * Since 2.10, this function allows to pass a negative @offset to
+ * step backwards.
+ * 
  * Return value: the resulting pointer
  **/
 gchar *
@@ -291,9 +294,29 @@ g_utf8_offset_to_pointer  (const gchar *str,
                           glong        offset)    
 {
   const gchar *s = str;
-  while (offset--)
-    s = g_utf8_next_char (s);
-  
+
+  if (offset > 0) 
+    while (offset--)
+      s = g_utf8_next_char (s);
+  else
+    {
+      const char *s1;
+
+      /* This nice technique for fast backwards stepping 
+       * through a UTF-8 string was dubbed "stutter stepping" 
+       * by its inventor, Larry Ewing.
+       */
+      while (offset)
+       {
+         s1 = s;
+         s += offset;
+         while ((*s & 0xc0) == 0x80)
+           s--;
+
+         offset += g_utf8_pointer_to_offset (s, s1);
+       }
+    }
+
   return (gchar *)s;
 }
 
@@ -304,6 +327,9 @@ g_utf8_offset_to_pointer  (const gchar *str,
  * 
  * Converts from a pointer to position within a string to a integer
  * character offset.
+ *
+ * Since 2.10, this function allows @pos to be before @str, and returns
+ * a negative offset in this case.
  * 
  * Return value: the resulting character offset
  **/
@@ -313,13 +339,16 @@ g_utf8_pointer_to_offset (const gchar *str,
 {
   const gchar *s = str;
   glong offset = 0;    
-  
-  while (s < pos)
-    {
-      s = g_utf8_next_char (s);
-      offset++;
-    }
 
+  if (pos < str) 
+    offset = - g_utf8_pointer_to_offset (pos, str);
+  else
+    while (s < pos)
+      {
+       s = g_utf8_next_char (s);
+       offset++;
+      }
+  
   return offset;
 }
 

diff --git a/tests/Makefile.am b/tests/Makefile.am
index a5336e4..3b61a2c 100644 (file)
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -103,6 +103,7 @@ test_programs =                                     \
        unicode-caseconv                        \
        unicode-encoding                        \
        utf8-validate                           \
+       utf8-pointer                            \
        uri-test
 
 test_scripts = run-markup-tests.sh run-collate-tests.sh
@@ -161,6 +162,7 @@ unicode_encoding_LDADD = $(progs_ldadd)
 unicode_caseconv_LDADD = $(progs_ldadd)
 unicode_collate_LDADD = $(progs_ldadd)
 utf8_validate_LDADD = $(progs_ldadd)
+utf8_pointer_LDADD = $(progs_ldadd)
 uri_test_LDADD = $(progs_ldadd)
 
 lib_LTLIBRARIES = libmoduletestplugin_a.la libmoduletestplugin_b.la

diff --git a/tests/utf8-pointer.c b/tests/utf8-pointer.c
new file mode 100644 (file)
index 0000000..3072851
--- /dev/null
+++ b/tests/utf8-pointer.c
@@ -0,0 +1,72 @@
+/* GLIB - Library of useful routines for C programming
+ * Copyright (C) 1995-1997  Peter Mattis, Spencer Kimball and Josh MacDonald
+ *
+ * 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 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., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+/*
+ * Modified by the GLib Team and others 1997-2000.  See the AUTHORS
+ * file for a list of people on the GLib Team.  See the ChangeLog
+ * files for a list of changes.  These files are distributed with
+ * GLib at ftp://ftp.gtk.org/pub/gtk/. 
+ */
+
+#include <glib.h>
+
+/* Test conversions between offsets and pointers */
+
+static void test_utf8 (gchar *string)
+{
+  gint num_chars;
+  gchar **p;
+  gint i, j;
+  
+  g_assert (g_utf8_validate (string, -1, NULL));
+  
+  num_chars = g_utf8_strlen (string, -1);
+  
+  p = (gchar **) g_malloc (num_chars * sizeof (gchar *));
+  
+  p[0] = string;
+  for (i = 1; i < num_chars; i++)
+    p[i] = g_utf8_next_char (p[i-1]);
+  
+  for (i = 0; i < num_chars; i++)
+    for (j = 0; j < num_chars; j++) 
+      {
+       g_assert (g_utf8_offset_to_pointer (p[i], j - i) == p[j]);      
+       g_assert (g_utf8_pointer_to_offset (p[i], p[j]) == j - i);      
+      }
+  
+  g_free (p);
+}
+
+gchar *longline = "asdasdas dsaf asfd as fdasdf asfd asdf as dfas dfasdf a"
+"asd fasdf asdf asdf asd fasfd as fdasfd asdf as fdççççççççças ffsd asfd as fdASASASAs As"
+"Asfdsf sdfg sdfg dsfg dfg sdfgsdfgsdfgsdfg sdfgsdfg sdfg sdfg sdf gsdfg sdfg sd"
+"asd fasdf asdf asdf asd fasfd as fdaèèèèèèè òòòòòòòòòòòòsfd asdf as fdas ffsd asfd as fdASASASAs D"
+"Asfdsf sdfg sdfg dsfg dfg sdfgsdfgsdfgsdfg sdfgsdfg sdfgùùùùùùùùùùùùùù sdfg sdf gsdfg sdfg sd"
+"asd fasdf asdf asdf asd fasfd as fdasfd asd@@@@@@@f as fdas ffsd asfd as fdASASASAs D "
+"Asfdsf sdfg sdfg dsfg dfg sdfgsdfgsdfgsdfg sdfgsdf€€€€€€€€€€€€€€€€€€g sdfg sdfg sdf gsdfg sdfg sd"
+"asd fasdf asdf asdf asd fasfd as fdasfd asdf as fdas ffsd asfd as fdASASASAs D"
+"Asfdsf sdfg sdfg dsfg dfg sdfgsdfgsdfgsdfg sdfgsdfg sdfg sdfg sdf gsdfg sdfg sd\n\nlalala\n";
+
+int main (int argc, char *argv[])
+{
+  test_utf8 (longline);
+  
+  return 0;
+}