1 files changed, 63 insertions, 0 deletions
diff --git a/modules/woff2/src/port.h b/modules/woff2/src/port.h
new file mode 100644
index 000000000..bac47a93a
--- /dev/null
+++ b/modules/woff2/src/port.h
@@ -0,0 +1,63 @@
+// Copyright 2013 Google Inc. All Rights Reserved.
+//
+// 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.
+//
+// Helper function for bit twiddling and macros for branch prediction.
+
+#ifndef WOFF2_PORT_H_
+#define WOFF2_PORT_H_
+
+#include <assert.h>
+
+namespace woff2 {
+
+typedef unsigned int       uint32;
+
+inline int Log2Floor(uint32 n) {
+#if defined(__GNUC__)
+  return n == 0 ? -1 : 31 ^ __builtin_clz(n);
+#else
+  if (n == 0)
+    return -1;
+  int log = 0;
+  uint32 value = n;
+  for (int i = 4; i >= 0; --i) {
+    int shift = (1 << i);
+    uint32 x = value >> shift;
+    if (x != 0) {
+      value = x;
+      log += shift;
+    }
+  }
+  assert(value == 1);
+  return log;
+#endif
+}
+
+} // namespace woff2
+
+/* Compatibility with non-clang compilers. */
+#ifndef __has_builtin
+#define __has_builtin(x) 0
+#endif
+
+#if (__GNUC__ > 2) || (__GNUC__ == 2 && __GNUC_MINOR__ > 95) || \
+    (defined(__llvm__) && __has_builtin(__builtin_expect))
+#define PREDICT_FALSE(x) (__builtin_expect(x, 0))
+#define PREDICT_TRUE(x) (__builtin_expect(!!(x), 1))
+#else
+#define PREDICT_FALSE(x) (x)
+#define PREDICT_TRUE(x) (x)
+#endif
+
+#endif  // WOFF2_PORT_H_