diff options
Diffstat (limited to 'vendor/github.com/golang/geo/s2/bits_go19.go')
-rw-r--r-- | vendor/github.com/golang/geo/s2/bits_go19.go | 39 |
1 files changed, 39 insertions, 0 deletions
diff --git a/vendor/github.com/golang/geo/s2/bits_go19.go b/vendor/github.com/golang/geo/s2/bits_go19.go new file mode 100644 index 000000000..9532b377d --- /dev/null +++ b/vendor/github.com/golang/geo/s2/bits_go19.go @@ -0,0 +1,39 @@ +// Copyright 2018 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. + +// +build go1.9 + +package s2 + +// This file is for the bit manipulation code post-Go 1.9. + +import "math/bits" + +// findMSBSetNonZero64 returns the index (between 0 and 63) of the most +// significant set bit. Passing zero to this function return zero. +func findMSBSetNonZero64(x uint64) int { + if x == 0 { + return 0 + } + return 63 - bits.LeadingZeros64(x) +} + +// findLSBSetNonZero64 returns the index (between 0 and 63) of the least +// significant set bit. Passing zero to this function return zero. +func findLSBSetNonZero64(x uint64) int { + if x == 0 { + return 0 + } + return bits.TrailingZeros64(x) +} |