PATCH: GString overwriting functions

["Samuel Cormier-Iijima" <sciyoshi gmail com>]

Hi everyone,

I've cooked up a small patch that adds overwriting functionality to
GStrings. It's explained in more detail in the bug report:
http://bugzilla.gnome.org/show_bug.cgi?id=368686
This is the first patch I've submitted to such a visible project, so
of course your standards are going to be much higher. I've added docs
and test cases in order to try to make your lives easier :-P. Comments
are welcome, I'd like to become more active in the open source world.
Thanks,

Samuel Cormier-Iijima

Index: glib/gstring.c
===================================================================
RCS file: /cvs/gnome/glib/glib/gstring.c,v
retrieving revision 1.49
diff -u -r1.49 gstring.c
--- glib/gstring.c	5 Dec 2005 15:38:52 -0000	1.49
+++ glib/gstring.c	1 Nov 2006 03:32:07 -0000
@@ -731,6 +731,80 @@
   return string;
 }
 
+/**
+ * g_string_overwrite:
+ * @string: a #GString
+ * @pos: the position at which to start overwriting
+ * @val: the string that will overwrite the @string starting at @pos
+ * 
+ * Overwrites part of a string, lengthening it if necessary.
+ * 
+ * Return value: @string
+ **/
+GString *
+g_string_overwrite (GString       *string,
+		    gssize          pos,
+		    const gchar   *val)
+{
+  gsize len;
+
+  g_return_val_if_fail (string != NULL, NULL);
+  g_return_val_if_fail (val != NULL, string);
+  g_return_val_if_fail (pos >= 0, string);
+  g_return_val_if_fail (pos <= string->len, string);
+
+  len = strlen (val);
+
+  g_string_maybe_expand (string, pos + len - string->len);
+
+  memcpy (string->str + pos, val, len);
+
+  if (pos + len > string->len)
+    string->str[pos + len] = '\0';
+
+  string->len = MAX (string->len, pos + len);
+
+  return string;
+}
+
+/**
+ * g_string_overwrite_len:
+ * @string: a #GString
+ * @pos: the position at which to start overwriting
+ * @val: the string that will overwrite the @string starting at @pos
+ * @len: the number of bytes to write from @val
+ * 
+ * Overwrites part of a string, lengthening it if necessary. This function
+ * will work with embedded NULLs.
+ * 
+ * Return value: @string
+ **/
+GString *
+g_string_overwrite_len (GString       *string,
+			gssize          pos,
+			const gchar   *val,
+			gsize          len)
+{
+  g_return_val_if_fail (string != NULL, NULL);
+  g_return_val_if_fail (val != NULL, string);
+  g_return_val_if_fail (pos >= 0, string);
+  g_return_val_if_fail (pos <= string->len, string);
+
+  if (len < 0)
+    len = strlen (val);
+
+  g_string_maybe_expand (string, pos + len - string->len);
+
+  memcpy (string->str + pos, val, len);
+
+  if (pos + len > string->len)
+    string->str[pos + len] = '\0';
+
+  string->len = MAX (string->len, pos + len);
+
+  return string;
+}
+
 GString*
 g_string_erase (GString *string,
 		gssize   pos,
Index: glib/gstring.h
===================================================================
RCS file: /cvs/gnome/glib/glib/gstring.h,v
retrieving revision 1.15
diff -u -r1.15 gstring.h
--- glib/gstring.h	2 Dec 2004 01:06:17 -0000	1.15
+++ glib/gstring.h	1 Nov 2006 03:32:07 -0000
@@ -104,6 +104,13 @@
 GString*     g_string_insert_unichar    (GString	 *string,
 					 gssize		  pos,    
 					 gunichar	  wc);
+GString*     g_string_overwrite         (GString	 *string,
+					 gssize		  pos,    
+					 const gchar	 *val);
+GString*     g_string_overwrite_len     (GString	 *string,
+					 gssize		  pos,    
+					 const gchar	 *val,
+					 gsize            len);
 GString*     g_string_erase	        (GString	 *string,
 					 gssize		  pos,
 					 gssize		  len);
Index: glib/glib.symbols
===================================================================
RCS file: /cvs/gnome/glib/glib/glib.symbols,v
retrieving revision 1.70
diff -u -r1.70 glib.symbols
--- glib/glib.symbols	9 Oct 2006 04:23:57 -0000	1.70
+++ glib/glib.symbols	1 Nov 2006 03:32:08 -0000
@@ -1092,6 +1092,8 @@
 g_string_insert_unichar
 g_string_new
 g_string_new_len
+g_string_overwrite
+g_string_overwrite_len
 g_string_prepend
 g_string_prepend_c
 g_string_prepend_len
Index: tests/string-test.c
===================================================================
RCS file: /cvs/gnome/glib/tests/string-test.c,v
retrieving revision 1.17
diff -u -r1.17 string-test.c
--- tests/string-test.c	18 Aug 2005 09:30:14 -0000	1.17
+++ tests/string-test.c	1 Nov 2006 03:32:08 -0000
@@ -257,6 +257,22 @@
   g_assert (g_string_equal(string1, string2));
   g_string_free (string1, TRUE);
   g_string_free (string2, TRUE);
+
+  /* overwriting functions */
+  string1 = g_string_new ("testing");
+  string2 = g_string_new ("teshi there");
+  g_string_overwrite (string1, 3, "hi there");
+  g_assert (g_string_equal (string1, string2));
+  g_string_overwrite (string1, 4, "53");
+  g_string_free (string2, TRUE);
+  string2 = g_string_new ("tesh53there");
+  g_assert (g_string_equal (string1, string2));
+  g_string_overwrite_len (string1, 8, "blabla", 4);
+  g_string_free (string2, TRUE);
+  string2 = g_string_new ("tesh53thblab");
+  g_assert (g_string_equal (string1, string2));
+  g_string_free (string1, TRUE);
+  g_string_free (string2, TRUE);
   
   /* Check handling of embedded ASCII 0 (NUL) characters in GString. */
   string1 = g_string_new ("fiddle");