diff options
Diffstat (limited to 'Firestore/core/src/firebase/firestore/util/bits.cc')
-rw-r--r-- | Firestore/core/src/firebase/firestore/util/bits.cc | 43 |
1 files changed, 43 insertions, 0 deletions
diff --git a/Firestore/core/src/firebase/firestore/util/bits.cc b/Firestore/core/src/firebase/firestore/util/bits.cc new file mode 100644 index 0000000..0bfe4c3 --- /dev/null +++ b/Firestore/core/src/firebase/firestore/util/bits.cc @@ -0,0 +1,43 @@ +/* + * Copyright 2017 Google + * + * 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. + */ + +#include "Firestore/core/src/firebase/firestore/util/bits.h" + +#include "Firestore/core/src/firebase/firestore/util/firebase_assert.h" + +namespace firebase { +namespace firestore { +namespace util { + +int Bits::Log2Floor_Portable(uint32_t n) { + if (n == 0) return -1; + int log = 0; + uint32_t value = n; + for (int i = 4; i >= 0; --i) { + int shift = (1 << i); + uint32_t x = value >> shift; + if (x != 0) { + value = x; + log += shift; + } + } + FIREBASE_ASSERT(value == 1); + return log; +} + +} // namespace util +} // namespace firestore +} // namespace firebase |