1 /* 2 * Copyright 2016 Google Inc. All Rights Reserved. 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package com.google.turbine.parse; 18 19 import com.google.turbine.diag.SourceFile; 20 import java.util.Iterator; 21 22 /** 23 * A {@link Lexer} that wraps an iterator over an existing token stream. 24 * 25 * <p>Used when parsing pre-processed constant expression initializers. 26 */ 27 public class IteratorLexer implements Lexer { 28 29 private final SourceFile source; 30 private final Iterator<SavedToken> it; 31 private SavedToken curr; 32 33 public IteratorLexer(SourceFile source, Iterator<SavedToken> it) { 34 this.source = source; 35 this.it = it; 36 } 37 38 @Override 39 public SourceFile source() { 40 return source; 41 } 42 43 @Override 44 public Token next() { 45 if (it.hasNext()) { 46 curr = it.next(); 47 return curr.token; 48 } 49 return Token.EOF; 50 } 51 52 @Override 53 public String stringValue() { 54 return curr.value; 55 } 56 57 @Override 58 public int position() { 59 // TODO(cushon): test expression position EOF handling 60 return curr != null ? curr.position : -1; 61 } 62 } 63
