sjansen/messageformat

package decoder

import "unicode/utf8"

type Decoder struct {
    src string
    idx int

    currSize int
    nextSize int
    currRune rune
    nextRune rune
}

func New(s string) *Decoder {
    ch, size := utf8.DecodeRuneInString(s)
    return &Decoder{
        src:      s,
        idx:      0,
        currRune: utf8.RuneError,
        currSize: 0,
        nextRune: ch,
        nextSize: size,
    }
}

func (d *Decoder) Decode() bool {
    if d.nextSize < 1 {
        return false
    }

    d.currRune = d.nextRune
    d.currSize = d.nextSize
    d.idx += d.currSize

    ch, size := utf8.DecodeRuneInString(d.src[d.idx:])
    d.nextRune = ch
    d.nextSize = size

    return true
}

func (d *Decoder) Decoded() rune {
    return d.currRune
}

func (d *Decoder) Peek() rune {
    return d.nextRune
}