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// Copyright 2018 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.
package protocol
import (
"fmt"
"unicode/utf8"
)
// CompareLocation defines a three-valued comparison over locations,
// lexicographically ordered by (URI, Range).
func CompareLocation(x, y Location) int {
if x.URI != y.URI {
if x.URI < y.URI {
return -1
} else {
return +1
}
}
return CompareRange(x.Range, y.Range)
}
// CompareRange returns -1 if a is before b, 0 if a == b, and 1 if a is after b.
//
// A range a is defined to be 'before' b if a.Start is before b.Start, or
// a.Start == b.Start and a.End is before b.End.
func CompareRange(a, b Range) int {
if r := ComparePosition(a.Start, b.Start); r != 0 {
return r
}
return ComparePosition(a.End, b.End)
}
// ComparePosition returns -1 if a is before b, 0 if a == b, and 1 if a is after b.
func ComparePosition(a, b Position) int {
if a.Line != b.Line {
if a.Line < b.Line {
return -1
} else {
return +1
}
}
if a.Character != b.Character {
if a.Character < b.Character {
return -1
} else {
return +1
}
}
return 0
}
func Intersect(a, b Range) bool {
if a.Start.Line > b.End.Line || a.End.Line < b.Start.Line {
return false
}
return !((a.Start.Line == b.End.Line) && a.Start.Character > b.End.Character ||
(a.End.Line == b.Start.Line) && a.End.Character < b.Start.Character)
}
// Format implements fmt.Formatter.
//
// Note: Formatter is implemented instead of Stringer (presumably) for
// performance reasons, though it is not clear that it matters in practice.
func (r Range) Format(f fmt.State, _ rune) {
fmt.Fprintf(f, "%v-%v", r.Start, r.End)
}
// Format implements fmt.Formatter.
//
// See Range.Format for discussion of why the Formatter interface is
// implemented rather than Stringer.
func (p Position) Format(f fmt.State, _ rune) {
fmt.Fprintf(f, "%v:%v", p.Line, p.Character)
}
// -- implementation helpers --
// UTF16Len returns the number of codes in the UTF-16 transcoding of s.
func UTF16Len(s []byte) int {
var n int
for len(s) > 0 {
n++
// Fast path for ASCII.
if s[0] < 0x80 {
s = s[1:]
continue
}
r, size := utf8.DecodeRune(s)
if r >= 0x10000 {
n++ // surrogate pair
}
s = s[size:]
}
return n
}
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