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gitea/vendor/github.com/dlclark/regexp2/syntax/replacerdata.go

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package syntax
import (
"bytes"
"errors"
)
type ReplacerData struct {
Rep string
Strings []string
Rules []int
}
const (
replaceSpecials = 4
replaceLeftPortion = -1
replaceRightPortion = -2
replaceLastGroup = -3
replaceWholeString = -4
)
//ErrReplacementError is a general error during parsing the replacement text
var ErrReplacementError = errors.New("Replacement pattern error.")
// NewReplacerData will populate a reusable replacer data struct based on the given replacement string
// and the capture group data from a regexp
func NewReplacerData(rep string, caps map[int]int, capsize int, capnames map[string]int, op RegexOptions) (*ReplacerData, error) {
p := parser{
options: op,
caps: caps,
capsize: capsize,
capnames: capnames,
}
p.setPattern(rep)
concat, err := p.scanReplacement()
if err != nil {
return nil, err
}
if concat.t != ntConcatenate {
panic(ErrReplacementError)
}
sb := &bytes.Buffer{}
var (
strings []string
rules []int
)
for _, child := range concat.children {
switch child.t {
case ntMulti:
child.writeStrToBuf(sb)
case ntOne:
sb.WriteRune(child.ch)
case ntRef:
if sb.Len() > 0 {
rules = append(rules, len(strings))
strings = append(strings, sb.String())
sb.Reset()
}
slot := child.m
if len(caps) > 0 && slot >= 0 {
slot = caps[slot]
}
rules = append(rules, -replaceSpecials-1-slot)
default:
panic(ErrReplacementError)
}
}
if sb.Len() > 0 {
rules = append(rules, len(strings))
strings = append(strings, sb.String())
}
return &ReplacerData{
Rep: rep,
Strings: strings,
Rules: rules,
}, nil
}