edu.princeton.cs.algs4.BinaryStdOut Maven / Gradle / Ivy
/******************************************************************************
* Compilation: javac BinaryStdOut.java
* Execution: java BinaryStdOut
* Dependencies: none
*
* Write binary data to standard output, either one 1-bit boolean,
* one 8-bit char, one 32-bit int, one 64-bit double, one 32-bit float,
* or one 64-bit long at a time.
*
* The bytes written are not aligned.
*
******************************************************************************/
package edu.princeton.cs.algs4;
import java.io.BufferedOutputStream;
import java.io.IOException;
/**
* Binary standard output. This class provides methods for converting
* primtive type variables ({@code boolean}, {@code byte}, {@code char},
* {@code int}, {@code long}, {@code float}, and {@code double})
* to sequences of bits and writing them to standard output.
* Uses big-endian (most-significant byte first).
*
* The client must {@code flush()} the output stream when finished writing bits.
*
* The client should not intermix calls to {@code BinaryStdOut} with calls
* to {@code StdOut} or {@code System.out}; otherwise unexpected behavior
* will result.
*
* @author Robert Sedgewick
* @author Kevin Wayne
*/
public final class BinaryStdOut {
private static BufferedOutputStream out; // output stream (standard output)
private static int buffer; // 8-bit buffer of bits to write
private static int n; // number of bits remaining in buffer
private static boolean isInitialized; // has BinaryStdOut been called for first time?
// don't instantiate
private BinaryStdOut() { }
// initialize BinaryStdOut
private static void initialize() {
out = new BufferedOutputStream(System.out);
buffer = 0;
n = 0;
isInitialized = true;
}
/**
* Writes the specified bit to standard output.
*/
private static void writeBit(boolean bit) {
if (!isInitialized) initialize();
// add bit to buffer
buffer <<= 1;
if (bit) buffer |= 1;
// if buffer is full (8 bits), write out as a single byte
n++;
if (n == 8) clearBuffer();
}
/**
* Writes the 8-bit byte to standard output.
*/
private static void writeByte(int x) {
if (!isInitialized) initialize();
assert x >= 0 && x < 256;
// optimized if byte-aligned
if (n == 0) {
try {
out.write(x);
}
catch (IOException e) {
e.printStackTrace();
}
return;
}
// otherwise write one bit at a time
for (int i = 0; i < 8; i++) {
boolean bit = ((x >>> (8 - i - 1)) & 1) == 1;
writeBit(bit);
}
}
// write out any remaining bits in buffer to standard output, padding with 0s
private static void clearBuffer() {
if (!isInitialized) initialize();
if (n == 0) return;
if (n > 0) buffer <<= (8 - n);
try {
out.write(buffer);
}
catch (IOException e) {
e.printStackTrace();
}
n = 0;
buffer = 0;
}
/**
* Flushes standard output, padding 0s if number of bits written so far
* is not a multiple of 8.
*/
public static void flush() {
clearBuffer();
try {
out.flush();
}
catch (IOException e) {
e.printStackTrace();
}
}
/**
* Flushes and closes standard output. Once standard output is closed, you can no
* longer write bits to it.
*/
public static void close() {
flush();
try {
out.close();
isInitialized = false;
}
catch (IOException e) {
e.printStackTrace();
}
}
/**
* Writes the specified bit to standard output.
* @param x the {@code boolean} to write.
*/
public static void write(boolean x) {
writeBit(x);
}
/**
* Writes the 8-bit byte to standard output.
* @param x the {@code byte} to write.
*/
public static void write(byte x) {
writeByte(x & 0xff);
}
/**
* Writes the 32-bit int to standard output.
* @param x the {@code int} to write.
*/
public static void write(int x) {
writeByte((x >>> 24) & 0xff);
writeByte((x >>> 16) & 0xff);
writeByte((x >>> 8) & 0xff);
writeByte((x >>> 0) & 0xff);
}
/**
* Writes the r-bit int to standard output.
* @param x the {@code int} to write.
* @param r the number of relevant bits in the char.
* @throws IllegalArgumentException if {@code r} is not between 1 and 32.
* @throws IllegalArgumentException if {@code x} is not between 0 and 2r - 1.
*/
public static void write(int x, int r) {
if (r == 32) {
write(x);
return;
}
if (r < 1 || r > 32) throw new IllegalArgumentException("Illegal value for r = " + r);
if (x < 0 || x >= (1 << r)) throw new IllegalArgumentException("Illegal " + r + "-bit char = " + x);
for (int i = 0; i < r; i++) {
boolean bit = ((x >>> (r - i - 1)) & 1) == 1;
writeBit(bit);
}
}
/**
* Writes the 64-bit double to standard output.
* @param x the {@code double} to write.
*/
public static void write(double x) {
write(Double.doubleToRawLongBits(x));
}
/**
* Writes the 64-bit long to standard output.
* @param x the {@code long} to write.
*/
public static void write(long x) {
writeByte((int) ((x >>> 56) & 0xff));
writeByte((int) ((x >>> 48) & 0xff));
writeByte((int) ((x >>> 40) & 0xff));
writeByte((int) ((x >>> 32) & 0xff));
writeByte((int) ((x >>> 24) & 0xff));
writeByte((int) ((x >>> 16) & 0xff));
writeByte((int) ((x >>> 8) & 0xff));
writeByte((int) ((x >>> 0) & 0xff));
}
/**
* Writes the 32-bit float to standard output.
* @param x the {@code float} to write.
*/
public static void write(float x) {
write(Float.floatToRawIntBits(x));
}
/**
* Writes the 16-bit int to standard output.
* @param x the {@code short} to write.
*/
public static void write(short x) {
writeByte((x >>> 8) & 0xff);
writeByte((x >>> 0) & 0xff);
}
/**
* Writes the 8-bit char to standard output.
* @param x the {@code char} to write.
* @throws IllegalArgumentException if {@code x} is not betwen 0 and 255.
*/
public static void write(char x) {
if (x < 0 || x >= 256) throw new IllegalArgumentException("Illegal 8-bit char = " + x);
writeByte(x);
}
/**
* Writes the r-bit char to standard output.
* @param x the {@code char} to write.
* @param r the number of relevant bits in the char.
* @throws IllegalArgumentException if {@code r} is not between 1 and 16.
* @throws IllegalArgumentException if {@code x} is not between 0 and 2r - 1.
*/
public static void write(char x, int r) {
if (r == 8) {
write(x);
return;
}
if (r < 1 || r > 16) throw new IllegalArgumentException("Illegal value for r = " + r);
if (x >= (1 << r)) throw new IllegalArgumentException("Illegal " + r + "-bit char = " + x);
for (int i = 0; i < r; i++) {
boolean bit = ((x >>> (r - i - 1)) & 1) == 1;
writeBit(bit);
}
}
/**
* Writes the string of 8-bit characters to standard output.
* @param s the {@code String} to write.
* @throws IllegalArgumentException if any character in the string is not
* between 0 and 255.
*/
public static void write(String s) {
for (int i = 0; i < s.length(); i++)
write(s.charAt(i));
}
/**
* Writes the string of r-bit characters to standard output.
* @param s the {@code String} to write.
* @param r the number of relevants bits in each character.
* @throws IllegalArgumentException if r is not between 1 and 16.
* @throws IllegalArgumentException if any character in the string is not
* between 0 and 2r - 1.
*/
public static void write(String s, int r) {
for (int i = 0; i < s.length(); i++)
write(s.charAt(i), r);
}
/**
* Tests the methods in this class.
*
* @param args the command-line arguments
*/
public static void main(String[] args) {
int m = Integer.parseInt(args[0]);
// write n integers to binary standard output
for (int i = 0; i < m; i++) {
BinaryStdOut.write(i);
}
BinaryStdOut.flush();
}
}
/******************************************************************************
* Copyright 2002-2018, Robert Sedgewick and Kevin Wayne.
*
* This file is part of algs4.jar, which accompanies the textbook
*
* Algorithms, 4th edition by Robert Sedgewick and Kevin Wayne,
* Addison-Wesley Professional, 2011, ISBN 0-321-57351-X.
* http://algs4.cs.princeton.edu
*
*
* algs4.jar is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* algs4.jar is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with algs4.jar. If not, see http://www.gnu.org/licenses.
******************************************************************************/