[tracker] Improve performance for SparqlBuilder.object_string

[Benjamin Otte <otte src gnome org>]

commit 0b76a1b75e07cf2db87d9ce543323278d7e58df3
Author: Benjamin Otte <otte gnome org>
Date:   Wed Jul 22 19:41:11 2009 +0200

    Improve performance for SparqlBuilder.object_string
    
    Don't check characters one-by-one but instead use strcspn to find the
    next character to escape. This improves performance for this function
    significantly.

 src/libtracker-common/tracker-sparql-builder.vala |   15 +++++++--------
 1 files changed, 7 insertions(+), 8 deletions(-)
---
diff --git a/src/libtracker-common/tracker-sparql-builder.vala b/src/libtracker-common/tracker-sparql-builder.vala
index d958747..a28e0d5 100644
--- a/src/libtracker-common/tracker-sparql-builder.vala
+++ b/src/libtracker-common/tracker-sparql-builder.vala
@@ -17,6 +17,9 @@
  * Boston, MA  02110-1301, USA.
  */
 
+[CCode (cname = "strcspn", cheader_filename = "string.h")]
+extern static size_t strcspn (string s1, string s2);
+
 public class Tracker.SparqlBuilder : Object {
 	enum State {
 		UPDATE,
@@ -124,6 +127,9 @@ public class Tracker.SparqlBuilder : Object {
 
 		char* p = literal;
 		while (*p != '\0') {
+			size_t len = strcspn ((string) p, "\t\n\r\"\\");
+			str.append_len ((string) p, (long) len);
+			p += len;
 			switch (*p) {
 			case '\t':
 				str.append ("\\t");
@@ -134,12 +140,6 @@ public class Tracker.SparqlBuilder : Object {
 			case '\r':
 				str.append ("\\r");
 				break;
-			case '\b':
-				str.append ("\\b");
-				break;
-			case '\f':
-				str.append ("\\f");
-				break;
 			case '"':
 				str.append ("\\\"");
 				break;
@@ -147,8 +147,7 @@ public class Tracker.SparqlBuilder : Object {
 				str.append ("\\\\");
 				break;
 			default:
-				str.append_c (*p);
-				break;
+				continue;
 			}
 			p++;
 		}