phrase_array.go

package libgochewing

import (
	"errors"
	"fmt"
)

type PhraseArray struct {
	array []*PhraseArrayItem
}

type PhraseArrayItem struct {
	phoneSeq []uint16
	phrase   []*Phrase
}

func newPhraseArray() (phraseArray *PhraseArray) {
	phraseArray = new(PhraseArray)
	phraseArray.array = make([]*PhraseArrayItem, 0, 1024)
	return phraseArray
}

func newPhraseArrayItem(phoneSeq []uint16) (phraseArrayItem *PhraseArrayItem) {
	phraseArrayItem = new(PhraseArrayItem)
	phraseArrayItem.phoneSeq = phoneSeq
	return phraseArrayItem
}

func (this *PhraseArray) insert(phrase *Phrase, phoneSeq []uint16) (err error) {
	begin := 0
	end := len(this.array)

	for begin < end {
		pos := (begin + end) / 2
		compare := comparePhoneSeq(this.array[pos].phoneSeq, phoneSeq, 0)

		if compare == 0 {
			return this.array[pos].insert(phrase)
		} else if compare > 0 {
			begin = pos + 1
		} else {
			end = pos
		}
	}

	this.array = append(this.array, nil)
	copy(this.array[begin+1:], this.array[begin:])

	newPhraseArrayItem := newPhraseArrayItem(phoneSeq)
	newPhraseArrayItem.insert(phrase)
	this.array[begin] = newPhraseArrayItem

	return nil
}

func (this *PhraseArrayItem) insert(phrase *Phrase) (err error) {
	pos := 0
	for i, item := range this.phrase {
		if isTheSamePhrase(item, phrase) {
			return errors.New(fmt.Sprintf("Phrase %s already in phrase tree", phrase.phrase))
		}

		if phrase.frequency < item.frequency {
			pos = i + 1
		}
	}

	this.phrase = append(this.phrase, nil)
	copy(this.phrase[pos+1:], this.phrase[pos:])
	this.phrase[pos] = phrase

	return nil
}

func (this *PhraseArrayItem) getLength() int {
	return len(this.phoneSeq)
}

func (this *PhraseArrayItem) getPhoneAtPos(pos int) uint16 {
	return this.phoneSeq[pos]
}