package nom.tam.util;


/*
 * This code is part of the Java FITS library developed 1996-2012 by T.A. McGlynn (NASA/GSFC)
 * The code is available in the public domain and may be copied, modified and used
 * by anyone in any fashion for any purpose without restriction. 
 * 
 * No warranty regarding correctness or performance of this code is given or implied.
 * Users may contact the author if they have questions or concerns.
 * 
 * The author would like to thank many who have contributed suggestions, 
 * enhancements and bug fixes including:
 * David Glowacki, R.J. Mathar, Laurent Michel, Guillaume Belanger,
 * Laurent Bourges, Rose Early, Fred Romelfanger, Jorgo Baker, A. Kovacs, V. Forchi, J.C. Segovia,
 * Booth Hartley and Jason Weiss.  
 * I apologize to any contributors whose names may have been inadvertently omitted.
 * 
 *      Tom McGlynn
 */

// What do we use in here?
import java.io.OutputStream;
import java.io.BufferedOutputStream;
import java.io.DataOutput;
import java.io.DataOutputStream;
import java.io.IOException;

/** This class is intended for high performance I/O in scientific applications.
 * It combines the functionality of the BufferedOutputStream and the
 * DataOutputStream as well as more efficient handling of arrays.
 * This minimizes the number of method calls that are required to
 * write data.  Informal tests of this method show that it can
 * be as much as 10 times faster than using a DataOutputStream layered
 * on a BufferedOutputStream for writing large arrays.  The performance
 * gain on scalars or small arrays will be less but there should probably
 * never be substantial degradation of performance.
 * <p>
 * Note that there is substantial duplication of code to minimize method
 * invocations.  However simple output methods were used where empirical
 * tests seemed to indicate that the simpler method did not cost any time.
 * It seems likely that most of these variations will be
 * washed out across different compilers and users who wish to tune
 * the method for their particular system may wish to compare the
 * the implementation of write(int[], int, int) with write(float[], int, int).
 * <p>
 * Testing and timing for this class is
 * peformed in the nom.tam.util.test.BufferedFileTester class.
 */
public class BufferedDataOutputStream
        extends BufferedOutputStream
        implements ArrayDataOutput {

    /** Use the BufferedOutputStream constructor
     * @param o An open output stream.
     */
    public BufferedDataOutputStream(OutputStream o) {
        super(o, 32768);
    }

    /** Use the BufferedOutputStream constructor
     * @param o           An open output stream.
     * @param bufLength   The buffer size.
     */
    public BufferedDataOutputStream(OutputStream o, int bufLength) {
        super(o, bufLength);
    }

    /** Write a boolean value
     * @param b  The value to be written.  Externally true is represented as
     *           a byte of 1 and false as a byte value of 0.
     */
    public void writeBoolean(boolean b) throws IOException {

        checkBuf(1);
        if (b) {
            buf[count++] = 1;
        } else {
            buf[count++] = 0;
        }
    }

    /** Write a byte value.
     */
    public void writeByte(int b) throws IOException {
        checkBuf(1);
        buf[count++] = (byte) b;
    }

    /** Write an integer value.
     */
    public void writeInt(int i) throws IOException {

        checkBuf(4);
        buf[count++] = (byte) (i >>> 24);
        buf[count++] = (byte) (i >>> 16);
        buf[count++] = (byte) (i >>> 8);
        buf[count++] = (byte) i;
    }

    /** Write a short value.
     */
    public void writeShort(int s) throws IOException {

        checkBuf(2);
        buf[count++] = (byte) (s >>> 8);
        buf[count++] = (byte) s;

    }

    /** Write a char value.
     */
    public void writeChar(int c) throws IOException {

        checkBuf(2);
        buf[count++] = (byte) (c >>> 8);
        buf[count++] = (byte) c;
    }

    /** Write a long value.
     */
    public void writeLong(long l) throws IOException {

        checkBuf(8);

        buf[count++] = (byte) (l >>> 56);
        buf[count++] = (byte) (l >>> 48);
        buf[count++] = (byte) (l >>> 40);
        buf[count++] = (byte) (l >>> 32);
        buf[count++] = (byte) (l >>> 24);
        buf[count++] = (byte) (l >>> 16);
        buf[count++] = (byte) (l >>> 8);
        buf[count++] = (byte) l;
    }

    /** Write a float value.
     */
    public void writeFloat(float f) throws IOException {

        checkBuf(4);

        int i = Float.floatToIntBits(f);

        buf[count++] = (byte) (i >>> 24);
        buf[count++] = (byte) (i >>> 16);
        buf[count++] = (byte) (i >>> 8);
        buf[count++] = (byte) i;


    }

    /** Write a double value.
     */
    public void writeDouble(double d) throws IOException {

        checkBuf(8);
        long l = Double.doubleToLongBits(d);

        buf[count++] = (byte) (l >>> 56);
        buf[count++] = (byte) (l >>> 48);
        buf[count++] = (byte) (l >>> 40);
        buf[count++] = (byte) (l >>> 32);
        buf[count++] = (byte) (l >>> 24);
        buf[count++] = (byte) (l >>> 16);
        buf[count++] = (byte) (l >>> 8);
        buf[count++] = (byte) l;

    }

    /** Write a string using the local protocol to convert char's to bytes.
     *
     * @param s   The string to be written.
     */
    public void writeBytes(String s) throws IOException {

        write(s.getBytes(), 0, s.length());
    }

    /** Write a string as an array of chars.
     */
    public void writeChars(String s) throws IOException {

        for (int i = 0; i < s.length(); i += 1) {
            writeChar(s.charAt(i));
        }
    }

    /** Write a string as a UTF.  Note that this class does not
     * handle this situation efficiently since it creates
     * new DataOutputStream to handle each call.
     */
    public void writeUTF(String s) throws IOException {

        // Punt on this one and use standard routines.
        DataOutputStream d = new DataOutputStream(this);
        d.writeUTF(s);
        d.flush();
        d.close();
    }

    /** This routine provides efficient writing of arrays of any primitive type.
     * The String class is also handled but it is an error to invoke this
     * method with an object that is not an array of these types.  If the
     * array is multidimensional, then it calls itself recursively to write
     * the entire array.  Strings are written using the standard
     * 1 byte format (i.e., as in writeBytes).
     *
     * If the array is an array of objects, then writePrimitiveArray will
     * be called for each element of the array.
     *
     * @param o  The object to be written.  It must be an array of a primitive
     *           type, Object, or String.
     */
    public void writePrimitiveArray(Object o) throws IOException {
        writeArray(o);
    }

    /** This routine provides efficient writing of arrays of any primitive type.
     * The String class is also handled but it is an error to invoke this
     * method with an object that is not an array of these types.  If the
     * array is multidimensional, then it calls itself recursively to write
     * the entire array.  Strings are written using the standard
     * 1 byte format (i.e., as in writeBytes).
     *
     * If the array is an array of objects, then writePrimitiveArray will
     * be called for each element of the array.
     *
     * @param o  The object to be written.  It must be an array of a primitive
     *           type, Object, or String.
     */
    public void writeArray(Object o) throws IOException {
        String className = o.getClass().getName();

        if (className.charAt(0) != '[') {
            throw new IOException("Invalid object passed to BufferedDataOutputStream.write" + className);
        }

        // Is this a multidimensional array?  If so process recursively.
        if (className.charAt(1) == '[') {
            for (int i = 0; i < ((Object[]) o).length; i += 1) {
                writeArray(((Object[]) o)[i]);
            }
        } else {

            // This is a one-d array.  Process it using our special functions.
            switch (className.charAt(1)) {
                case 'Z':
                    write((boolean[]) o, 0, ((boolean[]) o).length);
                    break;
                case 'B':
                    write((byte[]) o, 0, ((byte[]) o).length);
                    break;
                case 'C':
                    write((char[]) o, 0, ((char[]) o).length);
                    break;
                case 'S':
                    write((short[]) o, 0, ((short[]) o).length);
                    break;
                case 'I':
                    write((int[]) o, 0, ((int[]) o).length);
                    break;
                case 'J':
                    write((long[]) o, 0, ((long[]) o).length);
                    break;
                case 'F':
                    write((float[]) o, 0, ((float[]) o).length);
                    break;
                case 'D':
                    write((double[]) o, 0, ((double[]) o).length);
                    break;
                case 'L':

                    // Handle two exceptions: an array of strings, or an
                    // array of objects. .
                    if (className.equals("[Ljava.lang.String;")) {
                        write((String[]) o, 0, ((String[]) o).length);
                    } else if (className.equals("[Ljava.lang.Object;")) {
                        for (int i = 0; i < ((Object[]) o).length; i += 1) {
                            writeArray(((Object[]) o)[i]);
                        }
                    } else {
                        throw new IOException("Invalid object passed to BufferedDataOutputStream.writeArray: " + className);
                    }
                    break;
                default:
                    throw new IOException("Invalid object passed to BufferedDataOutputStream.writeArray: " + className);
            }
        }

    }

    /** Write an array of booleans.
     */
    public void write(boolean[] b) throws IOException {
        write(b, 0, b.length);
    }

    /** Write a segment of an array of booleans.
     */
    public void write(boolean[] b, int start, int len) throws IOException {

        for (int i = start; i < start + len; i += 1) {

            if (count + 1 > buf.length) {
                checkBuf(1);
            }
            if (b[i]) {
                buf[count++] = 1;
            } else {
                buf[count++] = 0;
            }
        }
    }

    /** Write an array of shorts.
     */
    public void write(short[] s) throws IOException {
        write(s, 0, s.length);
    }

    /** Write a segment of an array of shorts.
     */
    public void write(short[] s, int start, int len) throws IOException {

        for (int i = start; i < start + len; i += 1) {
            if (count + 2 > buf.length) {
                checkBuf(2);
            }
            buf[count++] = (byte) (s[i] >> 8);
            buf[count++] = (byte) (s[i]);
        }
    }

    /** Write an array of char's.
     */
    public void write(char[] c) throws IOException {
        write(c, 0, c.length);
    }

    /** Write a segment of an array of char's.
     */
    public void write(char[] c, int start, int len) throws IOException {

        for (int i = start; i < start + len; i += 1) {
            if (count + 2 > buf.length) {
                checkBuf(2);
            }
            buf[count++] = (byte) (c[i] >> 8);
            buf[count++] = (byte) (c[i]);
        }
    }

    /** Write an array of int's.
     */
    public void write(int[] i) throws IOException {
        write(i, 0, i.length);
    }

    /** Write a segment of an array of int's.
     */
    public void write(int[] i, int start, int len) throws IOException {

        for (int ii = start; ii < start + len; ii += 1) {
            if (count + 4 > buf.length) {
                checkBuf(4);
            }

            buf[count++] = (byte) (i[ii] >>> 24);
            buf[count++] = (byte) (i[ii] >>> 16);
            buf[count++] = (byte) (i[ii] >>> 8);
            buf[count++] = (byte) (i[ii]);

        }

    }

    /** Write an array of longs.
     */
    public void write(long[] l) throws IOException {
        write(l, 0, l.length);
    }

    /** Write a segement of an array of longs.
     */
    public void write(long[] l, int start, int len) throws IOException {

        for (int i = start; i < start + len; i += 1) {
            if (count + 8 > buf.length) {
                checkBuf(8);
            }
            int t = (int) (l[i] >>> 32);

            buf[count++] = (byte) (t >>> 24);
            buf[count++] = (byte) (t >>> 16);
            buf[count++] = (byte) (t >>> 8);
            buf[count++] = (byte) (t);

            t = (int) (l[i]);

            buf[count++] = (byte) (t >>> 24);
            buf[count++] = (byte) (t >>> 16);
            buf[count++] = (byte) (t >>> 8);
            buf[count++] = (byte) (t);
        }
    }

    /** Write an array of floats.
     */
    public void write(float[] f) throws IOException {
        write(f, 0, f.length);
    }

    public void write(float[] f, int start, int len) throws IOException {

        for (int i = start; i < start + len; i += 1) {

            if (count + 4 > buf.length) {
                checkBuf(4);
            }
            int t = Float.floatToIntBits(f[i]);
            buf[count++] = (byte) (t >>> 24);
            buf[count++] = (byte) (t >>> 16);
            buf[count++] = (byte) (t >>> 8);
            buf[count++] = (byte) t;
        }
    }

    /** Write an array of doubles.
     */
    public void write(double[] d) throws IOException {
        write(d, 0, d.length);
    }

    public void write(double[] d, int start, int len) throws IOException {

        for (int i = start; i < start + len; i += 1) {
            if (count + 8 > buf.length) {
                checkBuf(8);
            }
            long t = Double.doubleToLongBits(d[i]);

            int ix = (int) (t >>> 32);

            buf[count++] = (byte) (ix >>> 24);
            buf[count++] = (byte) (ix >>> 16);
            buf[count++] = (byte) (ix >>> 8);
            buf[count++] = (byte) (ix);

            ix = (int) t;

            buf[count++] = (byte) (ix >>> 24);
            buf[count++] = (byte) (ix >>> 16);
            buf[count++] = (byte) (ix >>> 8);
            buf[count++] = (byte) ix;
        }

    }

    /** Write an array of Strings -- equivalent to calling writeBytes for each string.
     */
    public void write(String[] s) throws IOException {
        write(s, 0, s.length);
    }

    /** Write a segment of an array of Strings.
     * Equivalent to calling writeBytes for the selected elements.
     */
    public void write(String[] s, int start, int len) throws IOException {

        // Do not worry about buffering this specially since the
        // strings may be of differing lengths.

        for (int i = 0; i < s.length; i += 1) {
            writeBytes(s[i]);
        }
    }

    /* See if there is enough space to add
     * something to the buffer.
     */
    protected void checkBuf(int need) throws IOException {

        if (count + need > buf.length) {
            out.write(buf, 0, count);
            count = 0;
        }
    }
}