/* * Cay S. Horstmann & Gary Cornell, Core Java * Published By Sun Microsystems Press/Prentice-Hall * Copyright (C) 1997 Sun Microsystems Inc. * All Rights Reserved. * * Permission to use, copy, modify, and distribute this * software and its documentation for NON-COMMERCIAL purposes * and without fee is hereby granted provided that this * copyright notice appears in all copies. * * THE AUTHORS AND PUBLISHER MAKE NO REPRESENTATIONS OR * WARRANTIES ABOUT THE SUITABILITY OF THE SOFTWARE, EITHER * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE * IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A * PARTICULAR PURPOSE, OR NON-INFRINGEMENT. THE AUTHORS * AND PUBLISHER SHALL NOT BE LIABLE FOR ANY DAMAGES SUFFERED * BY LICENSEE AS A RESULT OF USING, MODIFYING OR DISTRIBUTING * THIS SOFTWARE OR ITS DERIVATIVES. */ /** * A class for formatting numbers that follows printf conventions. * Also implements C-like atoi and atof functions * @version 1.01 15 Feb 1996 * @author Cay Horstmann */ package corejava; import java.io.*; public class Format { /** * Formats the number following printf conventions. * Main limitation: Can only handle one format parameter at a time * Use multiple Format objects to format more than one number * @param s the format string following printf conventions * The string has a prefix, a format code and a suffix. The prefix and suffix * become part of the formatted output. The format code directs the * formatting of the (single) parameter to be formatted. The code has the * following structure * * @exception IllegalArgumentException if bad format */ public Format(String s) { width = 0; precision = -1; pre = ""; post = ""; leading_zeroes = false; show_plus = false; alternate = false; show_space = false; left_align = false; fmt = ' '; int state = 0; int length = s.length(); int parse_state = 0; // 0 = prefix, 1 = flags, 2 = width, 3 = precision, // 4 = format, 5 = end int i = 0; while (parse_state == 0) { if (i >= length) parse_state = 5; else if (s.charAt(i) == '%') { if (i < length - 1) { if (s.charAt(i + 1) == '%') { pre = pre + '%'; i++; } else parse_state = 1; } else throw new java.lang.IllegalArgumentException(); } else pre = pre + s.charAt(i); i++; } while (parse_state == 1) { if (i >= length) parse_state = 5; else if (s.charAt(i) == ' ') show_space = true; else if (s.charAt(i) == '-') left_align = true; else if (s.charAt(i) == '+') show_plus = true; else if (s.charAt(i) == '0') leading_zeroes = true; else if (s.charAt(i) == '#') alternate = true; else { parse_state = 2; i--; } i++; } while (parse_state == 2) { if (i >= length) parse_state = 5; else if ('0' <= s.charAt(i) && s.charAt(i) <= '9') { width = width * 10 + s.charAt(i) - '0'; i++; } else if (s.charAt(i) == '.') { parse_state = 3; precision = 0; i++; } else parse_state = 4; } while (parse_state == 3) { if (i >= length) parse_state = 5; else if ('0' <= s.charAt(i) && s.charAt(i) <= '9') { precision = precision * 10 + s.charAt(i) - '0'; i++; } else parse_state = 4; } if (parse_state == 4) { if (i >= length) parse_state = 5; else fmt = s.charAt(i); i++; } if (i < length) post = s.substring(i, length); } /** * prints a formatted number following printf conventions * @param s a PrintStream * @param fmt the format string * @param x the double to print */ public static void print(java.io.PrintStream s, String fmt, double x) { s.print(new Format(fmt).form(x)); } /** * prints a formatted number following printf conventions * @param s a PrintStream * @param fmt the format string * @param x the long to print */ public static void print(java.io.PrintStream s, String fmt, long x) { s.print(new Format(fmt).form(x)); } /** * prints a formatted number following printf conventions * @param s a PrintStream * @param fmt the format string * @param x the character to */ public static void print(java.io.PrintStream s, String fmt, char x) { s.print(new Format(fmt).form(x)); } /** * prints a formatted number following printf conventions * @param s a PrintStream, fmt the format string * @param x a string that represents the digits to print */ public static void print(java.io.PrintStream s, String fmt, String x) { s.print(new Format(fmt).form(x)); } /** * Converts a string of digits (decimal, octal or hex) to an integer * @param s a string * @return the numeric value of the prefix of s representing a base 10 integer */ public static int atoi(String s) { return (int)atol(s); } /** * Converts a string of digits (decimal, octal or hex) to a long integer * @param s a string * @return the numeric value of the prefix of s representing a base 10 integer */ public static long atol(String s) { int i = 0; while (i < s.length() && Character.isWhitespace(s.charAt(i))) i++; if (i < s.length() && s.charAt(i) == '0') { if (i + 1 < s.length() && (s.charAt(i + 1) == 'x' || s.charAt(i + 1) == 'X')) return parseLong(s.substring(i + 2), 16); else return parseLong(s, 8); } else return parseLong(s, 10); } private static long parseLong(String s, int base) { int i = 0; int sign = 1; long r = 0; while (i < s.length() && Character.isWhitespace(s.charAt(i))) i++; if (i < s.length() && s.charAt(i) == '-') { sign = -1; i++; } else if (i < s.length() && s.charAt(i) == '+') { i++; } while (i < s.length()) { char ch = s.charAt(i); if ('0' <= ch && ch < '0' + base) r = r * base + ch - '0'; else if ('A' <= ch && ch < 'A' + base - 10) r = r * base + ch - 'A' + 10 ; else if ('a' <= ch && ch < 'a' + base - 10) r = r * base + ch - 'a' + 10 ; else return r * sign; i++; } return r * sign; } /** * Converts a string of digits to an double * @param s a string */ public static double atof(String s) { int i = 0; int sign = 1; double r = 0; // integer part double f = 0; // fractional part double p = 1; // exponent of fractional part int state = 0; // 0 = int part, 1 = frac part while (i < s.length() && Character.isWhitespace(s.charAt(i))) i++; if (i < s.length() && s.charAt(i) == '-') { sign = -1; i++; } else if (i < s.length() && s.charAt(i) == '+') { i++; } while (i < s.length()) { char ch = s.charAt(i); if ('0' <= ch && ch <= '9') { if (state == 0) r = r * 10 + ch - '0'; else if (state == 1) { p = p / 10; r = r + p * (ch - '0'); } } else if (ch == '.') { if (state == 0) state = 1; else return sign * r; } else if (ch == 'e' || ch == 'E') { long e = (int)parseLong(s.substring(i + 1), 10); return sign * r * Math.pow(10, e); } else return sign * r; i++; } return sign * r; } /** * Formats a double into a string (like sprintf in C) * @param x the number to format * @return the formatted string * @exception IllegalArgumentException if bad argument */ public String form(double x) { String r; if (precision < 0) precision = 6; int s = 1; if (x < 0) { x = -x; s = -1; } if (fmt == 'f') r = fixed_format(x); else if (fmt == 'e' || fmt == 'E' || fmt == 'g' || fmt == 'G') r = exp_format(x); else throw new java.lang.IllegalArgumentException(); return pad(sign(s, r)); } /** * Formats a long integer into a string (like sprintf in C) * @param x the number to format * @return the formatted string */ public String form(long x) { String r; int s = 0; if (fmt == 'd' || fmt == 'i') { s = 1; if (x < 0) { x = -x; s = -1; } r = "" + x; } else if (fmt == 'o') r = convert(x, 3, 7, "01234567"); else if (fmt == 'x') r = convert(x, 4, 15, "0123456789abcdef"); else if (fmt == 'X') r = convert(x, 4, 15, "0123456789ABCDEF"); else throw new java.lang.IllegalArgumentException(); return pad(sign(s, r)); } /** * Formats a character into a string (like sprintf in C) * @param x the value to format * @return the formatted string */ public String form(char c) { if (fmt != 'c') throw new java.lang.IllegalArgumentException(); String r = "" + c; return pad(r); } /** * Formats a string into a larger string (like sprintf in C) * @param x the value to format * @return the formatted string */ public String form(String s) { if (fmt != 's') throw new java.lang.IllegalArgumentException(); if (precision >= 0) s = s.substring(0, precision); return pad(s); } /** * a test stub for the format class */ public static void main(String[] a) { double x = 1.23456789012; double y = 123; double z = 1.2345e30; double w = 1.02; double u = 1.234e-5; int d = 0xCAFE; Format.print(System.out, "x = |%f|\n", x); Format.print(System.out, "u = |%20f|\n", u); Format.print(System.out, "x = |% .5f|\n", x); Format.print(System.out, "w = |%20.5f|\n", w); Format.print(System.out, "x = |%020.5f|\n", x); Format.print(System.out, "x = |%+20.5f|\n", x); Format.print(System.out, "x = |%+020.5f|\n", x); Format.print(System.out, "x = |% 020.5f|\n", x); Format.print(System.out, "y = |%#+20.5f|\n", y); Format.print(System.out, "y = |%-+20.5f|\n", y); Format.print(System.out, "z = |%20.5f|\n", z); Format.print(System.out, "x = |%e|\n", x); Format.print(System.out, "u = |%20e|\n", u); Format.print(System.out, "x = |% .5e|\n", x); Format.print(System.out, "w = |%20.5e|\n", w); Format.print(System.out, "x = |%020.5e|\n", x); Format.print(System.out, "x = |%+20.5e|\n", x); Format.print(System.out, "x = |%+020.5e|\n", x); Format.print(System.out, "x = |% 020.5e|\n", x); Format.print(System.out, "y = |%#+20.5e|\n", y); Format.print(System.out, "y = |%-+20.5e|\n", y); Format.print(System.out, "x = |%g|\n", x); Format.print(System.out, "z = |%g|\n", z); Format.print(System.out, "w = |%g|\n", w); Format.print(System.out, "u = |%g|\n", u); Format.print(System.out, "y = |%.2g|\n", y); Format.print(System.out, "y = |%#.2g|\n", y); Format.print(System.out, "d = |%d|\n", d); Format.print(System.out, "d = |%20d|\n", d); Format.print(System.out, "d = |%020d|\n", d); Format.print(System.out, "d = |%+20d|\n", d); Format.print(System.out, "d = |% 020d|\n", d); Format.print(System.out, "d = |%-20d|\n", d); Format.print(System.out, "d = |%20.8d|\n", d); Format.print(System.out, "d = |%x|\n", d); Format.print(System.out, "d = |%20X|\n", d); Format.print(System.out, "d = |%#20x|\n", d); Format.print(System.out, "d = |%020X|\n", d); Format.print(System.out, "d = |%20.8x|\n", d); Format.print(System.out, "d = |%o|\n", d); Format.print(System.out, "d = |%020o|\n", d); Format.print(System.out, "d = |%#20o|\n", d); Format.print(System.out, "d = |%#020o|\n", d); Format.print(System.out, "d = |%20.12o|\n", d); Format.print(System.out, "s = |%-20s|\n", "Hello"); Format.print(System.out, "s = |%-20c|\n", '!'); } private static String repeat(char c, int n) { if (n <= 0) return ""; StringBuffer s = new StringBuffer(n); for (int i = 0; i < n; i++) s.append(c); return s.toString(); } private static String convert(long x, int n, int m, String d) { if (x == 0) return "0"; String r = ""; while (x != 0) { r = d.charAt((int)(x & m)) + r; x = x >>> n; } return r; } private String pad(String r) { String p = repeat(' ', width - r.length()); if (left_align) return pre + r + p + post; else return pre + p + r + post; } private String sign(int s, String r) { String p = ""; if (s < 0) p = "-"; else if (s > 0) { if (show_plus) p = "+"; else if (show_space) p = " "; } else { if (fmt == 'o' && alternate && r.length() > 0 && r.charAt(0) != '0') p = "0"; else if (fmt == 'x' && alternate) p = "0x"; else if (fmt == 'X' && alternate) p = "0X"; } int w = 0; if (leading_zeroes) w = width; else if ((fmt == 'd' || fmt == 'i' || fmt == 'x' || fmt == 'X' || fmt == 'o') && precision > 0) w = precision; return p + repeat('0', w - p.length() - r.length()) + r; } private String fixed_format(double d) { String f = ""; if (d > 0x7FFFFFFFFFFFFFFFL) return exp_format(d); long l = (long)(precision == 0 ? d + 0.5 : d); f = f + l; double fr = d - l; // fractional part if (fr >= 1 || fr < 0) return exp_format(d); return f + frac_part(fr); } private String frac_part(double fr) // precondition: 0 <= fr < 1 { String z = ""; if (precision > 0) { double factor = 1; String leading_zeroes = ""; for (int i = 1; i <= precision && factor <= 0x7FFFFFFFFFFFFFFFL; i++) { factor *= 10; leading_zeroes = leading_zeroes + "0"; } long l = (long) (factor * fr + 0.5); z = leading_zeroes + l; z = z.substring(z.length() - precision, z.length()); } if (precision > 0 || alternate) z = "." + z; if ((fmt == 'G' || fmt == 'g') && !alternate) // remove trailing zeroes and decimal point { int t = z.length() - 1; while (t >= 0 && z.charAt(t) == '0') t--; if (t >= 0 && z.charAt(t) == '.') t--; z = z.substring(0, t + 1); } return z; } private String exp_format(double d) { String f = ""; int e = 0; double dd = d; double factor = 1; while (dd > 10) { e++; factor /= 10; dd = dd / 10; } while (dd < 1) { e--; factor *= 10; dd = dd * 10; } if ((fmt == 'g' || fmt == 'G') && e >= -4 && e < precision) return fixed_format(d); d = d * factor; f = f + fixed_format(d); if (fmt == 'e' || fmt == 'g') f = f + "e"; else f = f + "E"; String p = "000"; if (e >= 0) { f = f + "+"; p = p + e; } else { f = f + "-"; p = p + (-e); } return f + p.substring(p.length() - 3, p.length()); } private int width; private int precision; private String pre; private String post; private boolean leading_zeroes; private boolean show_plus; private boolean alternate; private boolean show_space; private boolean left_align; private char fmt; // one of cdeEfgGiosxXos }