Package com.yahoo.prelude.semantics.parser

Class AbstractCharStream

java.lang.Object
com.yahoo.prelude.semantics.parser.AbstractCharStream
All Implemented Interfaces:
CharStream
Direct Known Subclasses:
SimpleCharStream
public abstract class AbstractCharStream extends Object implements CharStream
An implementation of interface CharStream, where the stream is assumed to contain only ASCII characters (without unicode processing).

  • Field Details

    • DEFAULT_BUF_SIZE

      public static final int DEFAULT_BUF_SIZE
      See Also:

    • bufpos

      protected int bufpos
      Position in buffer.

    • bufsize

      protected int bufsize

    • available

      protected int available

    • tokenBegin

      protected int tokenBegin

    • bufline

      protected int[] bufline

    • bufcolumn

      protected int[] bufcolumn

    • column

      protected int column

    • line

      protected int line

    • prevCharIsCR

      protected boolean prevCharIsCR

    • prevCharIsLF

      protected boolean prevCharIsLF

    • buffer

      protected char[] buffer

    • maxNextCharInd

      protected int maxNextCharInd

    • inBuf

      protected int inBuf

    • nextCharBuf

      protected char[] nextCharBuf

    • nextCharInd

      protected int nextCharInd

  • Constructor Details

    • AbstractCharStream

      public AbstractCharStream(int startline, int startcolumn, int buffersize)
      Constructor.

  • Method Details

    • setTabSize

      public void setTabSize(int i)
      Description copied from interface: CharStream
      Set the tab size to use.
      Specified by:
      setTabSize in interface CharStream
      Parameters:
      i - spaces per tab

    • getTabSize

      public int getTabSize()
      Specified by:
      getTabSize in interface CharStream
      Returns:
      Current tab size.

    • expandBuff

      protected void expandBuff(boolean wrapAround)

    • streamRead

      protected abstract int streamRead(char[] buf, int offset, int len) throws IOException
      Throws:
      IOException

    • streamClose

      protected abstract void streamClose() throws IOException
      Throws:
      IOException

    • fillBuff

      protected void fillBuff() throws IOException
      Throws:
      IOException

    • beginToken

      public char beginToken() throws IOException
      Specified by:
      beginToken in interface CharStream
      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.
      Throws:
      IOException

    • updateLineColumn

      protected void updateLineColumn(char c)

    • readChar

      public char readChar() throws IOException
      Read a character.
      Specified by:
      readChar in interface CharStream
      Returns:
      the next character from the selected input
      Throws:
      IOException - on IO error

    • getBeginColumn

      public int getBeginColumn()
      Specified by:
      getBeginColumn in interface CharStream
      Returns:
      the column number of the first character for current token (being matched after the last call to beginToken).

    • getBeginLine

      public int getBeginLine()
      Specified by:
      getBeginLine in interface CharStream
      Returns:
      the line number of the first character for current token (being matched after the last call to BeginToken).

    • getEndColumn

      public int getEndColumn()
      Specified by:
      getEndColumn in interface CharStream
      Returns:
      the column number of the last character for current token (being matched after the last call to BeginToken).

    • getEndLine

      public int getEndLine()
      Specified by:
      getEndLine in interface CharStream
      Returns:
      the line number of the last character for current token (being matched after the last call to BeginToken).

    • backup

      public void backup(int amount)
      Description copied from interface: CharStream
      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.
      Specified by:
      backup in interface CharStream
      Parameters:
      amount - Number of chars to back up.

    • reInit

      public void reInit(int startline, int startcolumn, int buffersize)
      Reinitialise.

    • getImage

      public String getImage()
      Specified by:
      getImage in interface CharStream
      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.

    • getSuffix

      public char[] getSuffix(int len)
      Specified by:
      getSuffix in interface CharStream
      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();
   }

    • done

      public void done()
      Description copied from interface: CharStream
      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.
      Specified by:
      done in interface CharStream

    • adjustBeginLineColumn

      public void adjustBeginLineColumn(int nNewLine, int newCol)
      Method to adjust line and column numbers for the start of a token.

    • setTrackLineColumn

      public void setTrackLineColumn(boolean tlc)
      Description copied from interface: CharStream
      Enable or disable line number and column number tracking.
      Specified by:
      setTrackLineColumn in interface CharStream
      Parameters:
      tlc - true to track it, false to not do it.

    • isTrackLineColumn

      public boolean isTrackLineColumn()
      Specified by:
      isTrackLineColumn in interface CharStream
      Returns:
      true if line number and column numbers should be tracked.