66 lines
953 B
Go
66 lines
953 B
Go
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package token
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type TokenReader struct {
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in chan Token
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ts []Token
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r int
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}
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func NewTokenReader(in chan Token) *TokenReader {
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return &TokenReader{
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in: in,
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ts: []Token{},
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}
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}
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func (tr *TokenReader) Read(n int) ([]Token, bool) {
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toks := []Token{}
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for i := 0; i < n; i++ {
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tok, ok := tr.readOne()
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if !ok {
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tr.Unread(len(toks))
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return []Token{}, false
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}
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toks = append(toks, tok)
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}
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return toks, true
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}
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func (tr *TokenReader) Unread(n int) bool {
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//if n > tr.r {
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// return false
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//}
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for i := n; i > 0; i-- {
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tr.r--
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}
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return true
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}
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func (tr *TokenReader) Discard() {
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tr.ts = tr.ts[tr.r:]
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tr.r = 0
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}
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func (tr *TokenReader) readOne() (Token, bool) {
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if tr.r == len(tr.ts) {
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if ok := tr.consume(); !ok {
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return Token{}, false
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}
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}
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tok := tr.ts[tr.r]
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tr.r++
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return tok, true
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}
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func (tr *TokenReader) consume() bool {
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tok, ok := <-tr.in
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if !ok {
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return false
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}
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tr.ts = append(tr.ts, tok)
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return true
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}
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