packages/xdc/rov/StringReader.java

package xdc.rov;

import java.io.IOException;

import xdc.rta.IOFReader;

/*
 *  ======== StringReader ========
 */
public class StringReader implements IOFReader {

	MemoryImage memReader;
    
    /*! In fetchString, number of characters to read at a time. */
	public int nChars = 64;
	
	/*! In fetchString, maximum number of characters to read. */
	public int maxChars = 128;
	
	/*
	 *  ======== Constructor ========
	 */
	public StringReader(MemoryImage mem)
	{
		this.memReader = mem;
	}
	
	/*
	 *  ======== findString ========
	 *  Retrieves a string from the given address, reading until it reaches a null
	 *  char or until it has read 'maxChars'. 
	 *  StructureDecoder.nChars controls how many characters are read at a time. It
	 *  would be an optimization to make nChars greater than 1, but currently the
	 *  implementation does not support this--it would need to handle the case
	 *  where a string is at the end of a data section, and the read goes past the
	 *  end of the data section due to nChar.
	 */    
	public String findString(long addr, boolean addrCheck) {
	    /* String to return. */
	    String res = "";
	    
	    /* 
	     * Read characters, nChars at a time, until we reach a null character or
	     * maxChars.
	     */
	    for (long a = addr; a < addr + maxChars ; a += nChars) {
	    	
	    	int[] buf = null;
	    	
	    	/* Read nChars */
	        try {
	        	buf = memReader.readMaus(a, nChars, addrCheck);
	        }
	        catch (Exception e) {
	        	return (res);
	        }
	        
	        /* Decode each char */
	        for (int i = 0; i < nChars; i++) {
	            int b = buf[i];
	            if (b == 0) {
	                return (res);
	            }
	            res += (char) b;
	        }
	    }

	    return (res);
	}

	/*
     *  ======== findString ========
     *  findString API to satisfy the IOFReader interface.
     *  This API simply calls findString with 'false' for the address check.
     */
    public String findString(long addr)
    {
        return (findString(addr, false));
    }
    
	/*
	 * ======== parse ========
	 * (non-Javadoc)
	 * @see xdc.rta.IOFReader#parse(java.lang.String)
	 */
	public String parse(String arg0) throws IOException {
		return null;
	}
	
	/*
	 * ======== close ========
	 * (non-Javadoc)
	 * @see xdc.rta.IOFReader#close()
	 */
	public void close() throws IOException {
	}

    public static IOFReader getOFReaderByName(String className) throws Exception
    {
        Class c = Class.forName(className);
        return ((IOFReader) c.newInstance());
    }
}