replacer.go 1.0 KB

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  1. package stringx
  2. import (
  3. "bytes"
  4. )
  5. type (
  6. // Replacer interface wraps the Replace method.
  7. Replacer interface {
  8. Replace(text string) string
  9. }
  10. replacer struct {
  11. *node
  12. mapping map[string]string
  13. }
  14. )
  15. // NewReplacer returns a Replacer.
  16. func NewReplacer(mapping map[string]string) Replacer {
  17. rep := &replacer{
  18. node: new(node),
  19. mapping: mapping,
  20. }
  21. for k := range mapping {
  22. rep.add(k)
  23. }
  24. rep.build()
  25. return rep
  26. }
  27. // Replace replaces text with given substitutes.
  28. func (r *replacer) Replace(text string) string {
  29. var buf bytes.Buffer
  30. target := []rune(text)
  31. cur := r.node
  32. nextStart := 0
  33. for len(target) != 0 {
  34. used, jump, matched := cur.longestMatch(target, nextStart)
  35. if matched {
  36. replaced := r.mapping[string(target[:used])]
  37. target = append([]rune(replaced), target[used:]...)
  38. cur = r.node
  39. } else {
  40. buf.WriteString(string(target[:used]))
  41. target = target[used:]
  42. if jump != nil {
  43. cur = jump
  44. nextStart = jump.depth
  45. } else {
  46. cur = r.node
  47. nextStart = 0
  48. }
  49. }
  50. }
  51. return buf.String()
  52. }