diff options
author | 2024-08-02 11:46:41 +0000 | |
---|---|---|
committer | 2024-08-02 12:46:41 +0100 | |
commit | 94e87610c4ce9bbb1c614a61bab29c1422fed11b (patch) | |
tree | 2e06b8ce64212140e796f6077ba841b6cc678501 /vendor/github.com/golang/geo/s2/bits_go18.go | |
parent | [feature] Allow import of following and blocks via CSV (#3150) (diff) | |
download | gotosocial-94e87610c4ce9bbb1c614a61bab29c1422fed11b.tar.xz |
[chore] add back exif-terminator and use only for jpeg,png,webp (#3161)
* add back exif-terminator and use only for jpeg,png,webp
* fix arguments passed to terminateExif()
* pull in latest exif-terminator
* fix test
* update processed img
---------
Co-authored-by: tobi <tobi.smethurst@protonmail.com>
Diffstat (limited to 'vendor/github.com/golang/geo/s2/bits_go18.go')
-rw-r--r-- | vendor/github.com/golang/geo/s2/bits_go18.go | 53 |
1 files changed, 53 insertions, 0 deletions
diff --git a/vendor/github.com/golang/geo/s2/bits_go18.go b/vendor/github.com/golang/geo/s2/bits_go18.go new file mode 100644 index 000000000..10a674da5 --- /dev/null +++ b/vendor/github.com/golang/geo/s2/bits_go18.go @@ -0,0 +1,53 @@ +// 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 pre-Go 1.9. + +// findMSBSetNonZero64 returns the index (between 0 and 63) of the most +// significant set bit. Passing zero to this function returns zero. +func findMSBSetNonZero64(x uint64) int { + val := []uint64{0x2, 0xC, 0xF0, 0xFF00, 0xFFFF0000, 0xFFFFFFFF00000000} + shift := []uint64{1, 2, 4, 8, 16, 32} + var msbPos uint64 + for i := 5; i >= 0; i-- { + if x&val[i] != 0 { + x >>= shift[i] + msbPos |= shift[i] + } + } + return int(msbPos) +} + +const deBruijn64 = 0x03f79d71b4ca8b09 +const digitMask = uint64(1<<64 - 1) + +var deBruijn64Lookup = []byte{ + 0, 1, 56, 2, 57, 49, 28, 3, 61, 58, 42, 50, 38, 29, 17, 4, + 62, 47, 59, 36, 45, 43, 51, 22, 53, 39, 33, 30, 24, 18, 12, 5, + 63, 55, 48, 27, 60, 41, 37, 16, 46, 35, 44, 21, 52, 32, 23, 11, + 54, 26, 40, 15, 34, 20, 31, 10, 25, 14, 19, 9, 13, 8, 7, 6, +} + +// findLSBSetNonZero64 returns the index (between 0 and 63) of the least +// significant set bit. Passing zero to this function returns zero. +// +// This code comes from trailingZeroBits in https://golang.org/src/math/big/nat.go +// which references (Knuth, volume 4, section 7.3.1). +func findLSBSetNonZero64(x uint64) int { + return int(deBruijn64Lookup[((x&-x)*(deBruijn64&digitMask))>>58]) +} |