1 /*
   2  * Copyright (c) 2010, 2013, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package jdk.nashorn.internal.parser;
  27 
  28 import static jdk.nashorn.internal.parser.TokenKind.LITERAL;
  29 
  30 import jdk.nashorn.internal.runtime.Source;
  31 
  32 /**
  33  * Basic parse/lex unit.
  34  *
  35  */
  36 public class Token {
  37 
  38     private Token() {
  39     }
  40 
  41     /**
  42      * Create a compact form of token information.
  43      * @param type     Type of token.
  44      * @param position Start position of the token in the source.
  45      * @param length   Length of the token.
  46      * @return Token descriptor.
  47      */
  48     public static long toDesc(final TokenType type, final int position, final int length) {
  49         return (long)position << 32 |
  50                (long)length   << 8  |
  51                type.ordinal();
  52     }
  53 
  54     /**
  55      * Extract token position from a token descriptor.
  56      * @param token Token descriptor.
  57      * @return Start position of the token in the source.
  58      */
  59     public static int descPosition(final long token) {
  60         return (int)(token >>> 32);
  61     }
  62 
  63     /**
  64      * Normally returns the token itself, except in case of string tokens
  65      * which report their position past their opening delimiter and thus
  66      * need to have position and length adjusted.
  67      *
  68      * @param token Token descriptor.
  69      * @return same or adjusted token.
  70      */
  71     public static long withDelimiter(final long token) {
  72         final TokenType tokenType = Token.descType(token);
  73         switch(tokenType) {
  74             case STRING: case ESCSTRING: case EXECSTRING: {
  75                 final int start = Token.descPosition(token) - 1;
  76                 final int len = Token.descLength(token) + 2;
  77                 return toDesc(tokenType, start, len);
  78             }
  79             default: {
  80                 return token;
  81             }
  82         }
  83     }
  84 
  85     /**
  86      * Extract token length from a token descriptor.
  87      * @param token Token descriptor.
  88      * @return Length of the token.
  89      */
  90     public static int descLength(final long token) {
  91         return (int)token >>> 8;
  92     }
  93 
  94     /**
  95      * Extract token type from a token descriptor.
  96      * @param token Token descriptor.
  97      * @return Type of token.
  98      */
  99     public static TokenType descType(final long token) {
 100         return TokenType.getValues()[(int)token & 0xff];
 101     }
 102 
 103     /**
 104      * Change the token to use a new type.
 105      *
 106      * @param token   The original token.
 107      * @param newType The new token type.
 108      * @return The recast token.
 109      */
 110     public static long recast(final long token, final TokenType newType) {
 111         return token & ~0xFFL | newType.ordinal();
 112     }
 113 
 114     /**
 115      * Return a string representation of a token.
 116      * @param source  Token source.
 117      * @param token   Token descriptor.
 118      * @param verbose True to include details.
 119      * @return String representation.
 120      */
 121     public static String toString(final Source source, final long token, final boolean verbose) {
 122         final TokenType type = Token.descType(token);
 123         String result;
 124 
 125         if (source != null && type.getKind() == LITERAL) {
 126             result = source.getString(token);
 127         } else {
 128             result = type.getNameOrType();
 129         }
 130 
 131         if (verbose) {
 132             final int position = Token.descPosition(token);
 133             final int length = Token.descLength(token);
 134             result += " (" + position + ", " + length + ")";
 135         }
 136 
 137         return result;
 138     }
 139 
 140     /**
 141      * String conversion of token
 142      *
 143      * @param source the source
 144      * @param token  the token
 145      *
 146      * @return token as string
 147      */
 148     public static String toString(final Source source, final long token) {
 149         return Token.toString(source, token, false);
 150     }
 151 
 152     /**
 153      * String conversion of token - version without source given
 154      *
 155      * @param token  the token
 156      *
 157      * @return token as string
 158      */
 159     public static String toString(final long token) {
 160         return Token.toString(null, token, false);
 161     }
 162 
 163     /**
 164      * Static hash code computation function token
 165      *
 166      * @param token a token
 167      *
 168      * @return hash code for token
 169      */
 170     public static int hashCode(final long token) {
 171         return (int)(token ^ token >>> 32);
 172     }
 173 
 174 }
--- EOF ---