001: /* Generated By:JavaCC: Do not edit this line. CharStream.java Version 4.1 */
002: /* JavaCCOptions:STATIC=false */
003: package org.netbeans.modules.css.parser;
004:
005: /**
006: * This interface describes a character stream that maintains line and
007: * column number positions of the characters. It also has the capability
008: * to backup the stream to some extent. An implementation of this
009: * interface is used in the TokenManager implementation generated by
010: * JavaCCParser.
011: *
012: * All the methods except backup can be implemented in any fashion. backup
013: * needs to be implemented correctly for the correct operation of the lexer.
014: * Rest of the methods are all used to get information like line number,
015: * column number and the String that constitutes a token and are not used
016: * by the lexer. Hence their implementation won't affect the generated lexer's
017: * operation.
018: */
019:
020: public interface CharStream {
021:
022: /**
023: * Returns the next character from the selected input. The method
024: * of selecting the input is the responsibility of the class
025: * implementing this interface. Can throw any java.io.IOException.
026: */
027: char readChar() throws java.io.IOException;
028:
029: //marek
030: int offset();
031:
032: /**
033: * Returns the column position of the character last read.
034: * @deprecated
035: * @see #getEndColumn
036: */
037: int getColumn();
038:
039: /**
040: * Returns the line number of the character last read.
041: * @deprecated
042: * @see #getEndLine
043: */
044: int getLine();
045:
046: /**
047: * Returns the column number of the last character for current token (being
048: * matched after the last call to BeginTOken).
049: */
050: int getEndColumn();
051:
052: /**
053: * Returns the line number of the last character for current token (being
054: * matched after the last call to BeginTOken).
055: */
056: int getEndLine();
057:
058: /**
059: * Returns the column number of the first character for current token (being
060: * matched after the last call to BeginTOken).
061: */
062: int getBeginColumn();
063:
064: /**
065: * Returns the line number of the first character for current token (being
066: * matched after the last call to BeginTOken).
067: */
068: int getBeginLine();
069:
070: /**
071: * Backs up the input stream by amount steps. Lexer calls this method if it
072: * had already read some characters, but could not use them to match a
073: * (longer) token. So, they will be used again as the prefix of the next
074: * token and it is the implemetation's responsibility to do this right.
075: */
076: void backup(int amount);
077:
078: /**
079: * Returns the next character that marks the beginning of the next token.
080: * All characters must remain in the buffer between two successive calls
081: * to this method to implement backup correctly.
082: */
083: char BeginToken() throws java.io.IOException;
084:
085: /**
086: * Returns a string made up of characters from the marked token beginning
087: * to the current buffer position. Implementations have the choice of returning
088: * anything that they want to. For example, for efficiency, one might decide
089: * to just return null, which is a valid implementation.
090: */
091: String GetImage();
092:
093: /**
094: * Returns an array of characters that make up the suffix of length 'len' for
095: * the currently matched token. This is used to build up the matched string
096: * for use in actions in the case of MORE. A simple and inefficient
097: * implementation of this is as follows :
098: *
099: * {
100: * String t = GetImage();
101: * return t.substring(t.length() - len, t.length()).toCharArray();
102: * }
103: */
104: char[] GetSuffix(int len);
105:
106: /**
107: * The lexer calls this function to indicate that it is done with the stream
108: * and hence implementations can free any resources held by this class.
109: * Again, the body of this function can be just empty and it will not
110: * affect the lexer's operation.
111: */
112: void Done();
113:
114: }
115: /* JavaCC - OriginalChecksum=43fed9179152c61937918ac39480df74 (do not edit this line) */
|