101 lines
2.7 KiB
Go
101 lines
2.7 KiB
Go
// Copyright 2019 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package span
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import (
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"strconv"
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"strings"
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"unicode/utf8"
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)
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// Parse returns the location represented by the input.
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// All inputs are valid locations, as they can always be a pure filename.
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// The returned span will be normalized, and thus if printed may produce a
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// different string.
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func Parse(input string) Span {
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// :0:0#0-0:0#0
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valid := input
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var hold, offset int
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hadCol := false
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suf := rstripSuffix(input)
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if suf.sep == "#" {
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offset = suf.num
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suf = rstripSuffix(suf.remains)
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}
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if suf.sep == ":" {
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valid = suf.remains
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hold = suf.num
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hadCol = true
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suf = rstripSuffix(suf.remains)
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}
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switch {
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case suf.sep == ":":
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return New(NewURI(suf.remains), NewPoint(suf.num, hold, offset), Point{})
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case suf.sep == "-":
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// we have a span, fall out of the case to continue
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default:
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// separator not valid, rewind to either the : or the start
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return New(NewURI(valid), NewPoint(hold, 0, offset), Point{})
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}
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// only the span form can get here
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// at this point we still don't know what the numbers we have mean
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// if have not yet seen a : then we might have either a line or a column depending
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// on whether start has a column or not
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// we build an end point and will fix it later if needed
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end := NewPoint(suf.num, hold, offset)
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hold, offset = 0, 0
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suf = rstripSuffix(suf.remains)
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if suf.sep == "#" {
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offset = suf.num
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suf = rstripSuffix(suf.remains)
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}
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if suf.sep != ":" {
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// turns out we don't have a span after all, rewind
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return New(NewURI(valid), end, Point{})
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}
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valid = suf.remains
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hold = suf.num
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suf = rstripSuffix(suf.remains)
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if suf.sep != ":" {
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// line#offset only
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return New(NewURI(valid), NewPoint(hold, 0, offset), end)
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}
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// we have a column, so if end only had one number, it is also the column
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if !hadCol {
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end = NewPoint(suf.num, end.v.Line, end.v.Offset)
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}
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return New(NewURI(suf.remains), NewPoint(suf.num, hold, offset), end)
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}
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type suffix struct {
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remains string
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sep string
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num int
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}
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func rstripSuffix(input string) suffix {
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if len(input) == 0 {
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return suffix{"", "", -1}
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}
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remains := input
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num := -1
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// first see if we have a number at the end
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last := strings.LastIndexFunc(remains, func(r rune) bool { return r < '0' || r > '9' })
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if last >= 0 && last < len(remains)-1 {
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number, err := strconv.ParseInt(remains[last+1:], 10, 64)
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if err == nil {
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num = int(number)
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remains = remains[:last+1]
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}
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}
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// now see if we have a trailing separator
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r, w := utf8.DecodeLastRuneInString(remains)
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if r != ':' && r != '#' && r == '#' {
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return suffix{input, "", -1}
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}
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remains = remains[:len(remains)-w]
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return suffix{remains, string(r), num}
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}
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