/* Generated By:JavaCC: Do not edit this line. CharStream.java Version 5.0 */
/* JavaCCOptions:STATIC=false,SUPPORT_CLASS_VISIBILITY_PUBLIC=true */
package org.eclipse.rdf4j.query.parser.sparql.ast;

/**
 * This interface describes a character stream that maintains line and column number positions of the characters. It
 * also has the capability to backup the stream to some extent. An implementation of this interface is used in the
 * TokenManager implementation generated by JavaCCParser.
 *
 * All the methods except backup can be implemented in any fashion. backup needs to be implemented correctly for the
 * correct operation of the lexer. Rest of the methods are all used to get information like line number, column number
 * and the String that constitutes a token and are not used by the lexer. Hence their implementation won't affect the
 * generated lexer's operation.
 */

public interface CharStream {

	/**
	 * Returns the next character from the selected input. The method of selecting the input is the responsibility of
	 * the class implementing this interface. Can throw any java.io.IOException.
	 */
	char readChar() throws java.io.IOException;

	@Deprecated
	/**
	 * Returns the column position of the character last read.
	 *
	 * @deprecated
	 * @see #getEndColumn
	 */
	int getColumn();

	@Deprecated
	/**
	 * Returns the line number of the character last read.
	 *
	 * @deprecated
	 * @see #getEndLine
	 */
	int getLine();

	/**
	 * Returns the column number of the last character for current token (being matched after the last call to
	 * BeginTOken).
	 */
	int getEndColumn();

	/**
	 * Returns the line number of the last character for current token (being matched after the last call to
	 * BeginTOken).
	 */
	int getEndLine();

	/**
	 * Returns the column number of the first character for current token (being matched after the last call to
	 * BeginTOken).
	 */
	int getBeginColumn();

	/**
	 * Returns the line number of the first character for current token (being matched after the last call to
	 * BeginTOken).
	 */
	int getBeginLine();

	/**
	 * Backs up the input stream by amount steps. Lexer calls this method if it had already read some characters, but
	 * could not use them to match a (longer) token. So, they will be used again as the prefix of the next token and it
	 * is the implemetation's responsibility to do this right.
	 */
	void backup(int amount);

	/**
	 * Returns the next character that marks the beginning of the next token. All characters must remain in the buffer
	 * between two successive calls to this method to implement backup correctly.
	 */
	char BeginToken() throws java.io.IOException;

	/**
	 * Returns a string made up of characters from the marked token beginning to the current buffer position.
	 * Implementations have the choice of returning anything that they want to. For example, for efficiency, one might
	 * decide to just return null, which is a valid implementation.
	 */
	String GetImage();

	/**
	 * Returns an array of characters that make up the suffix of length 'len' for the currently matched token. This is
	 * used to build up the matched string for use in actions in the case of MORE. A simple and inefficient
	 * implementation of this is as follows :
	 *
	 * { String t = GetImage(); return t.substring(t.length() - len, t.length()).toCharArray(); }
	 */
	char[] GetSuffix(int len);

	/**
	 * The lexer calls this function to indicate that it is done with the stream and hence implementations can free any
	 * resources held by this class. Again, the body of this function can be just empty and it will not affect the
	 * lexer's operation.
	 */
	void Done();

}
/* JavaCC - OriginalChecksum=d5d02d7f2852c9b712f39bed41ca22b5 (do not edit this line) */
