104 lines
2.5 KiB
Go
104 lines
2.5 KiB
Go
/*
|
|
Copyright 2020 The Go4 AUTHORS
|
|
|
|
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.
|
|
*/
|
|
|
|
package mem
|
|
|
|
import (
|
|
"unicode"
|
|
"unicode/utf8"
|
|
)
|
|
|
|
var asciiSpace = [256]uint8{'\t': 1, '\n': 1, '\v': 1, '\f': 1, '\r': 1, ' ': 1}
|
|
|
|
// AppendFields is like strings.Fields, but is append-like and uses a mem.RO instead of a string.
|
|
func AppendFields(dst []RO, m RO) []RO {
|
|
s := m.m
|
|
|
|
// Copied from the Go standard library (BSD license).
|
|
|
|
// First count the fields.
|
|
// This is an exact count if s is ASCII, otherwise it is an approximation.
|
|
n := 0
|
|
wasSpace := 1
|
|
// setBits is used to track which bits are set in the bytes of s.
|
|
setBits := uint8(0)
|
|
for i := 0; i < len(s); i++ {
|
|
r := s[i]
|
|
setBits |= r
|
|
isSpace := int(asciiSpace[r])
|
|
n += wasSpace & ^isSpace
|
|
wasSpace = isSpace
|
|
}
|
|
|
|
if setBits >= utf8.RuneSelf {
|
|
// Some runes in the input string are not ASCII.
|
|
return AppendFieldsFunc(dst, m, unicode.IsSpace)
|
|
}
|
|
// ASCII fast path
|
|
fieldStart := 0
|
|
i := 0
|
|
// Skip spaces in the front of the input.
|
|
for i < len(s) && asciiSpace[s[i]] != 0 {
|
|
i++
|
|
}
|
|
fieldStart = i
|
|
for i < len(s) {
|
|
if asciiSpace[s[i]] == 0 {
|
|
i++
|
|
continue
|
|
}
|
|
dst = append(dst, RO{m: s[fieldStart:i]})
|
|
i++
|
|
// Skip spaces in between fields.
|
|
for i < len(s) && asciiSpace[s[i]] != 0 {
|
|
i++
|
|
}
|
|
fieldStart = i
|
|
}
|
|
if fieldStart < len(s) { // Last field might end at EOF.
|
|
dst = append(dst, RO{m: s[fieldStart:]})
|
|
}
|
|
return dst
|
|
}
|
|
|
|
// AppendFieldsFunc is like strings.FieldsFunc, but is append-like and uses a mem.RO instead of a string.
|
|
func AppendFieldsFunc(dst []RO, m RO, f func(rune) bool) []RO {
|
|
s := string(m.m)
|
|
|
|
// Find the field start and end indices.
|
|
wasField := false
|
|
fromIndex := 0
|
|
for i, rune := range s {
|
|
if f(rune) {
|
|
if wasField {
|
|
dst = append(dst, RO{m: unsafeString(s[fromIndex:i])})
|
|
wasField = false
|
|
}
|
|
} else {
|
|
if !wasField {
|
|
fromIndex = i
|
|
wasField = true
|
|
}
|
|
}
|
|
}
|
|
|
|
// Last field might end at EOF.
|
|
if wasField {
|
|
dst = append(dst, RO{m: unsafeString(s[fromIndex:len(s)])})
|
|
}
|
|
return dst
|
|
}
|