// 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 #ifndef WOFF2_PORT_H_ #define WOFF2_PORT_H_ #include 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 #endif // WOFF2_PORT_H_