mirror of
https://github.com/golang/go
synced 2024-09-30 16:28:32 -06:00
b40df0fb21
This implements a standard way of describing source locations along with printing and parsing of those locations and conversion to and from the token.Pos forms. Change-Id: Ibb3df0a282bc2effb0fa8bd3a51bb0d281b2ffb1 Reviewed-on: https://go-review.googlesource.com/c/tools/+/163778 Run-TryBot: Ian Cottrell <iancottrell@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Rebecca Stambler <rstambler@golang.org>
40 lines
888 B
Go
40 lines
888 B
Go
// 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
|
|
}
|
|
}
|
|
}
|