From 9810803358445e47a6ee5cfe1385f7de551be852 Mon Sep 17 00:00:00 2001
From: Matthias Clasen <mclasen@redhat.com>
Date: Fri, 13 Jan 2023 22:21:01 -0500
Subject: [PATCH] string: Optimize g_string_append(_len)

Add static inline versions of these functions
that boil down to just an memcpy. ag_string_append_len
is used quite a bit in GMarkup and GTK's css parser.
---
 glib/gstring.c | 15 +++++++--------
 glib/gstring.h | 31 +++++++++++++++++++++++++++++++
 2 files changed, 38 insertions(+), 8 deletions(-)

diff --git a/glib/gstring.c b/glib/gstring.c
index e3a491f81..ed6f03123 100644
--- a/glib/gstring.c
+++ b/glib/gstring.c
@@ -539,8 +539,8 @@ g_string_append_uri_escaped (GString     *string,
  * Returns: (transfer none): @string
  */
 GString *
-g_string_append (GString     *string,
-                 const gchar *val)
+(g_string_append) (GString     *string,
+                   const gchar *val)
 {
   return g_string_insert_len (string, -1, val, -1);
 }
@@ -564,9 +564,9 @@ g_string_append (GString     *string,
  * Returns: (transfer none): @string
  */
 GString *
-g_string_append_len (GString     *string,
-                     const gchar *val,
-                     gssize       len)
+(g_string_append_len) (GString     *string,
+                       const gchar *val,
+                       gssize       len)
 {
   return g_string_insert_len (string, -1, val, len);
 }
@@ -581,10 +581,9 @@ g_string_append_len (GString     *string,
  *
  * Returns: (transfer none): @string
  */
-#undef g_string_append_c
 GString *
-g_string_append_c (GString *string,
-                   gchar    c)
+(g_string_append_c) (GString *string,
+                     gchar    c)
 {
   g_return_val_if_fail (string != NULL, NULL);
 
diff --git a/glib/gstring.h b/glib/gstring.h
index 8e4cc5657..70888217c 100644
--- a/glib/gstring.h
+++ b/glib/gstring.h
@@ -35,6 +35,7 @@
 #include <glib/gunicode.h>
 #include <glib/gbytes.h>
 #include <glib/gutils.h>  /* for G_CAN_INLINE */
+#include <string.h>
 
 G_BEGIN_DECLS
 
@@ -178,6 +179,36 @@ g_string_append_c_inline (GString *gstring,
   return gstring;
 }
 #define g_string_append_c(gstr,c)       g_string_append_c_inline (gstr, c)
+
+static inline GString *
+g_string_append_len_inline (GString    *gstring,
+                            const char *val,
+                            gssize      len)
+{
+  if (len < 0)
+    len = strlen (val);
+
+  if (G_LIKELY (gstring->len + len < gstring->allocated_len))
+    {
+      char *end = gstring->str + gstring->len;
+      if (G_LIKELY (val + len <= end || val > end + len))
+        memcpy (end, val, len);
+      else
+        memmove (end, val, len);
+      gstring->len += len;
+      gstring->str[gstring->len] = 0;
+      return gstring;
+    }
+  else
+    return g_string_insert_len (gstring, -1, val, len);
+}
+#define g_string_append_len(gstr,val,len) g_string_append_len_inline (gstr, val, len)
+
+#if G_GNUC_CHECK_VERSION (2, 0)
+
+#define g_string_append(gstr,val) g_string_append_len (gstr, val, __builtin_constant_p (val) ? (gssize) strlen (val) : (gssize) -1)
+#endif
+
 #endif /* G_CAN_INLINE */