[Kst] kdeextragear-2/kst/kst

[George Staikos]

CVS commit by staikos: 

statistical optimisations in the ascii file reading code - check the common
case before the uncommon case.


  M +14 -9     kstfile.cpp   1.23


--- kdeextragear-2/kst/kst/kstfile.cpp  #1.22:1.23
@@ -494,32 +494,37 @@ bool KstFile::asciiUpdate(){
 
     is_comment = has_dat = false;
-    for (i_buf=0; i_buf<bufread; i_buf++) {
+    for (i_buf = 0; i_buf < bufread; i_buf++) {
       if (tmpbuf[i_buf] == '\n') {
         if (has_dat) {
           NumFrames++;
-          if (NumFrames>=NumLinesAlloc) {
+          if (NumFrames >= NumLinesAlloc) {
             RowIndex = (int *)realloc(RowIndex,
                                       (NumLinesAlloc + 32768)*sizeof(int));
             NumLinesAlloc += 32768;
           }
-          new_data=true;
+          new_data = true;
         }
         RowIndex[NumFrames] = bufstart + i_buf+1;
         has_dat = is_comment = false;
-      } else if ((tmpbuf[i_buf] == '#') || (tmpbuf[i_buf] == '!') ||
-                 (tmpbuf[i_buf] == '/') || (tmpbuf[i_buf] == ';') ||
-                 (tmpbuf[i_buf] == 'c')) {
-        is_comment = true;
+      // Statistically numbers should be more common than comments, so let's
+      // check for them first
+      // if isdigit() generates a function call, it would be better to write
+      // this inline, but I'm not convinced that compilers are that stupid yet.
+      // Profiling shows this code path gets hit 10^5+ times.
       } else if (isdigit(tmpbuf[i_buf])) {
         if (!is_comment) {
           has_dat = true;
         }
+      } else if (tmpbuf[i_buf] == '#' || tmpbuf[i_buf] == '!' ||
+                 tmpbuf[i_buf] == '/' || tmpbuf[i_buf] == ';' ||
+                 tmpbuf[i_buf] == 'c') {
+        is_comment = true;
       }
     }
-  } while (bufread==MAXBUFREADLEN);
+  } while (bufread == MAXBUFREADLEN);
 
   ascii_file.close();
 
-  return (new_data);
+  return new_data;
 }