Below is the syntax highlighted version of BinaryStdIn.java.
/****************************************************************************** * Compilation: javac BinaryStdIn.java * Execution: java BinaryStdIn < input > output * Dependencies: none * * Supports reading binary data from standard input. * * % java BinaryStdIn < input.jpg > output.jpg * % diff input.jpg output.jpg * ******************************************************************************/ package edu.princeton.cs.algs4; import java.io.BufferedInputStream; import java.io.IOException; import java.util.NoSuchElementException; /** * The <code>BinaryStdIn</code> class provides static methods for reading * in bits from standard input. It can process the bits * one bit at a time (as a {@code boolean}), * 8 bits at a time (as a {@code byte} or {@code char}), * 16 bits at a time (as a {@code short}), 32 bits at a time * (as an {@code int} or {@code float}), or 64 bits at a time (as a * {@code double} or {@code long}). * <p> * All primitive types are assumed to be represented using their * standard Java representations, in big-endian (most significant * byte first) order. * <p> * The client should not intermix calls to {@code BinaryStdIn} with calls * to {@code StdIn} or {@code System.in}; * otherwise unexpected behavior will result. * * @author Robert Sedgewick * @author Kevin Wayne */ public final class BinaryStdIn { private static final int EOF = -1; // end of file private static BufferedInputStream in; // input stream private static int buffer; // one character buffer private static int n; // number of bits left in buffer private static boolean isInitialized; // has BinaryStdIn been called for first time? // don't instantiate private BinaryStdIn() { } // fill buffer private static void initialize() { in = new BufferedInputStream(System.in); buffer = 0; n = 0; fillBuffer(); isInitialized = true; } private static void fillBuffer() { try { buffer = in.read(); n = 8; } catch (IOException e) { System.out.println("EOF"); buffer = EOF; n = -1; } } /** * Close this input stream and release any associated system resources. */ public static void close() { if (!isInitialized) initialize(); try { in.close(); isInitialized = false; } catch (IOException ioe) { throw new IllegalStateException("Could not close BinaryStdIn", ioe); } } /** * Returns true if standard input is empty. * @return true if and only if standard input is empty */ public static boolean isEmpty() { if (!isInitialized) initialize(); return buffer == EOF; } /** * Reads the next bit of data from standard input and return as a boolean. * * @return the next bit of data from standard input as a {@code boolean} * @throws NoSuchElementException if standard input is empty */ public static boolean readBoolean() { if (isEmpty()) throw new NoSuchElementException("Reading from empty input stream"); n--; boolean bit = ((buffer >> n) & 1) == 1; if (n == 0) fillBuffer(); return bit; } /** * Reads the next 8 bits from standard input and return as an 8-bit char. * Note that {@code char} is a 16-bit type; * to read the next 16 bits as a char, use {@code readChar(16)}. * * @return the next 8 bits of data from standard input as a {@code char} * @throws NoSuchElementException if there are fewer than 8 bits available on standard input */ public static char readChar() { if (isEmpty()) throw new NoSuchElementException("Reading from empty input stream"); // special case when aligned byte if (n == 8) { int x = buffer; fillBuffer(); return (char) (x & 0xff); } // combine last n bits of current buffer with first 8-n bits of new buffer int x = buffer; x <<= (8 - n); int oldN = n; fillBuffer(); if (isEmpty()) throw new NoSuchElementException("Reading from empty input stream"); n = oldN; x |= (buffer >>> n); return (char) (x & 0xff); // the above code doesn't quite work for the last character if n = 8 // because buffer will be -1, so there is a special case for aligned byte } /** * Reads the next <em>r</em> bits from standard input and return as an <em>r</em>-bit character. * * @param r number of bits to read. * @return the next r bits of data from standard input as a {@code char} * @throws NoSuchElementException if there are fewer than {@code r} bits available on standard input * @throws IllegalArgumentException unless {@code 1 <= r <= 16} */ public static char readChar(int r) { if (r < 1 || r > 16) throw new IllegalArgumentException("Illegal value of r = " + r); // optimize r = 8 case if (r == 8) return readChar(); char x = 0; for (int i = 0; i < r; i++) { x <<= 1; boolean bit = readBoolean(); if (bit) x |= 1; } return x; } /** * Reads the remaining bytes of data from standard input and return as a string. * * @return the remaining bytes of data from standard input as a {@code String} * @throws NoSuchElementException if standard input is empty or if the number of bits * available on standard input is not a multiple of 8 (byte-aligned) */ public static String readString() { if (isEmpty()) throw new NoSuchElementException("Reading from empty input stream"); StringBuilder sb = new StringBuilder(); while (!isEmpty()) { char c = readChar(); sb.append(c); } return sb.toString(); } /** * Reads the next 16 bits from standard input and return as a 16-bit short. * * @return the next 16 bits of data from standard input as a {@code short} * @throws NoSuchElementException if there are fewer than 16 bits available on standard input */ public static short readShort() { short x = 0; for (int i = 0; i < 2; i++) { char c = readChar(); x <<= 8; x |= c; } return x; } /** * Reads the next 32 bits from standard input and return as a 32-bit int. * * @return the next 32 bits of data from standard input as a {@code int} * @throws NoSuchElementException if there are fewer than 32 bits available on standard input */ public static int readInt() { int x = 0; for (int i = 0; i < 4; i++) { char c = readChar(); x <<= 8; x |= c; } return x; } /** * Reads the next <em>r</em> bits from standard input and return as an <em>r</em>-bit int. * * @param r number of bits to read. * @return the next r bits of data from standard input as a {@code int} * @throws NoSuchElementException if there are fewer than {@code r} bits available on standard input * @throws IllegalArgumentException unless {@code 1 <= r <= 32} */ public static int readInt(int r) { if (r < 1 || r > 32) throw new IllegalArgumentException("Illegal value of r = " + r); // optimize r = 32 case if (r == 32) return readInt(); int x = 0; for (int i = 0; i < r; i++) { x <<= 1; boolean bit = readBoolean(); if (bit) x |= 1; } return x; } /** * Reads the next 64 bits from standard input and return as a 64-bit long. * * @return the next 64 bits of data from standard input as a {@code long} * @throws NoSuchElementException if there are fewer than 64 bits available on standard input */ public static long readLong() { long x = 0; for (int i = 0; i < 8; i++) { char c = readChar(); x <<= 8; x |= c; } return x; } /** * Reads the next 64 bits from standard input and return as a 64-bit double. * * @return the next 64 bits of data from standard input as a {@code double} * @throws NoSuchElementException if there are fewer than 64 bits available on standard input */ public static double readDouble() { return Double.longBitsToDouble(readLong()); } /** * Reads the next 32 bits from standard input and return as a 32-bit float. * * @return the next 32 bits of data from standard input as a {@code float} * @throws NoSuchElementException if there are fewer than 32 bits available on standard input */ public static float readFloat() { return Float.intBitsToFloat(readInt()); } /** * Reads the next 8 bits from standard input and return as an 8-bit byte. * * @return the next 8 bits of data from standard input as a {@code byte} * @throws NoSuchElementException if there are fewer than 8 bits available on standard input */ public static byte readByte() { char c = readChar(); return (byte) (c & 0xff); } /** * Test client. Reads in a binary input file from standard input and writes * it to standard output. * * @param args the command-line arguments */ public static void main(String[] args) { // read one 8-bit char at a time while (!BinaryStdIn.isEmpty()) { char c = BinaryStdIn.readChar(); BinaryStdOut.write(c); } BinaryStdOut.flush(); } } /****************************************************************************** * Copyright 2002-2022, 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. ******************************************************************************/