diff options
Diffstat (limited to 'vendor/github.com/hexops/gotextdiff/span/token111.go')
| -rw-r--r-- | vendor/github.com/hexops/gotextdiff/span/token111.go | 39 |
1 files changed, 39 insertions, 0 deletions
diff --git a/vendor/github.com/hexops/gotextdiff/span/token111.go b/vendor/github.com/hexops/gotextdiff/span/token111.go new file mode 100644 index 000000000..bf7a5406b --- /dev/null +++ b/vendor/github.com/hexops/gotextdiff/span/token111.go @@ -0,0 +1,39 @@ +// Copyright 2019 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +// +build !go1.12 + +package span + +import ( + "go/token" +) + +// lineStart is the pre-Go 1.12 version of (*token.File).LineStart. For Go +// versions <= 1.11, we borrow logic from the analysisutil package. +// TODO(rstambler): Delete this file when we no longer support Go 1.11. +func lineStart(f *token.File, line int) token.Pos { + // Use binary search to find the start offset of this line. + + min := 0 // inclusive + max := f.Size() // exclusive + for { + offset := (min + max) / 2 + pos := f.Pos(offset) + posn := f.Position(pos) + if posn.Line == line { + return pos - (token.Pos(posn.Column) - 1) + } + + if min+1 >= max { + return token.NoPos + } + + if posn.Line < line { + min = offset + } else { + max = offset + } + } +} |
