Boost performance of QChar::isSpace

Make it inline; add fast checks for typical spaces;
add fallback function that uses the fastcall calling
convention.

On ia32, this change makes isSpace ~340x faster for
ascii spaces, ~170x faster for non-space ascii
characters, and ~1.3x faster for non-ascii characters.

Note that this change is NOT binary compatible.

Also add an autotest with expected results from
before the optimization, to ensure that the behavior
is the same.

Change-Id: I9438d0ad3c9ba2e80560c4bee7eed05115265798
Reviewed-on: http://codereview.qt-project.org/4905
Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: Lars Knoll <lars.knoll@nokia.com>

1 files changed, 9 insertions, 4 deletions

diff --git a/src/corelib/tools/qchar.cpp b/src/corelib/tools/qchar.cpp
index 56773bd527..a60fac4a7b 100644
--- a/src/corelib/tools/qchar.cpp
+++ b/src/corelib/tools/qchar.cpp
@@ -511,18 +511,23 @@ bool QChar::isPrint() const
 }
 
 /*!
+    \fn bool QChar::isSpace() const
+
     Returns true if the character is a separator character
     (Separator_* categories or certain code points from Other_Control category);
     otherwise returns false.
 */
-bool QChar::isSpace() const
+
+/*!
+    \internal
+    \overload
+*/
+bool QChar::isSpace(ushort ucs2)
 {
-    if(ucs >= 9 && ucs <=13)
-        return true;
     const int test = FLAG(Separator_Space) |
                      FLAG(Separator_Line) |
                      FLAG(Separator_Paragraph);
-    return FLAG(qGetProp(ucs)->category) & test;
+    return FLAG(qGetProp(ucs2)->category) & test;
 }
 
 /*!