add gpu backend (not hooked up yet)



git-svn-id: http://skia.googlecode.com/svn/trunk@649 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/gpu/include/GrTBSearch.h b/gpu/include/GrTBSearch.h
new file mode 100644
index 0000000..264ccb0
--- /dev/null
+++ b/gpu/include/GrTBSearch.h
@@ -0,0 +1,53 @@
+/*
+    Copyright 2010 Google Inc.
+
+    Licensed under the Apache License, Version 2.0 (the "License");
+    you may not use this file except in compliance with the License.
+    You may obtain a copy of the License at
+
+         http://www.apache.org/licenses/LICENSE-2.0
+
+    Unless required by applicable law or agreed to in writing, software
+    distributed under the License is distributed on an "AS IS" BASIS,
+    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+    See the License for the specific language governing permissions and
+    limitations under the License.
+ */
+
+
+#ifndef GrTBSearch_DEFINED
+#define GrTBSearch_DEFINED
+
+template <typename ELEM, typename KEY>
+int GrTBSearch(const ELEM array[], int count, KEY target) {
+    GrAssert(count >= 0);
+    if (0 == count) {
+        // we should insert it at 0
+        return ~0;
+    }
+    
+    int high = count - 1;
+    int low = 0;
+    while (high > low) {
+        int index = (low + high) >> 1;
+        if (LT(array[index], target)) {
+            low = index + 1;
+        } else {
+            high = index;
+        }
+    }
+    
+    // check if we found it
+    if (EQ(array[high], target)) {
+        return high;
+    }
+    
+    // now return the ~ of where we should insert it
+    if (LT(array[high], target)) {
+        high += 1;
+    }
+    return ~high;
+}
+
+#endif
+