2 * Cay S. Horstmann & Gary Cornell, Core Java
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3 * Published By Sun Microsystems Press/Prentice-Hall
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4 * Copyright (C) 1997 Sun Microsystems Inc.
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5 * All Rights Reserved.
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7 * Permission to use, copy, modify, and distribute this
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8 * software and its documentation for NON-COMMERCIAL purposes
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9 * and without fee is hereby granted provided that this
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10 * copyright notice appears in all copies.
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12 * THE AUTHORS AND PUBLISHER MAKE NO REPRESENTATIONS OR
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13 * WARRANTIES ABOUT THE SUITABILITY OF THE SOFTWARE, EITHER
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14 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
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15 * IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
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16 * PARTICULAR PURPOSE, OR NON-INFRINGEMENT. THE AUTHORS
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17 * AND PUBLISHER SHALL NOT BE LIABLE FOR ANY DAMAGES SUFFERED
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18 * BY LICENSEE AS A RESULT OF USING, MODIFYING OR DISTRIBUTING
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19 * THIS SOFTWARE OR ITS DERIVATIVES.
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23 * A class for formatting numbers that follows printf conventions.
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24 * Also implements C-like atoi and atof functions
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25 * @version 1.03 25 Oct 1997
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26 * @author Cay Horstmann
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29 package uk.ac.vamsas.objects.utils;
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33 public class Format { /**
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34 * Formats the number following printf conventions.
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35 * Main limitation: Can only handle one format parameter at a time
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36 * Use multiple Format objects to format more than one number
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37 * @param s the format string following printf conventions
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38 * The string has a prefix, a format code and a suffix. The prefix and suffix
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39 * become part of the formatted output. The format code directs the
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40 * formatting of the (single) parameter to be formatted. The code has the
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41 * following structure
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43 * <li> a % (required)
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44 * <li> a modifier (optional)
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46 * <dt> + <dd> forces display of + for positive numbers
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47 * <dt> 0 <dd> show leading zeroes
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48 * <dt> - <dd> align left in the field
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49 * <dt> space <dd> prepend a space in front of positive numbers
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50 * <dt> # <dd> use "alternate" format. Add 0 or 0x for octal or hexadecimal numbers. Don't suppress trailing zeroes in general floating point format.
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52 * <li> an integer denoting field width (optional)
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53 * <li> a period followed by an integer denoting precision (optional)
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54 * <li> a format descriptor (required)
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56 * <dt>f <dd> floating point number in fixed format
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57 * <dt>e, E <dd> floating point number in exponential notation (scientific format). The E format results in an uppercase E for the exponent (1.14130E+003), the e format in a lowercase e.
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58 * <dt>g, G <dd> floating point number in general format (fixed format for small numbers, exponential format for large numbers). Trailing zeroes are suppressed. The G format results in an uppercase E for the exponent (if any), the g format in a lowercase e.
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59 * <dt>d, i <dd> integer in decimal
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60 * <dt>x <dd> integer in hexadecimal
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61 * <dt>o <dd> integer in octal
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63 * <dt>c <dd> character
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66 * @exception IllegalArgumentException if bad format
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69 public Format(String s) {
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74 leading_zeroes = false;
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82 int length = s.length();
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83 int parse_state = 0;
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84 // 0 = prefix, 1 = flags, 2 = width, 3 = precision,
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85 // 4 = format, 5 = end
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88 while (parse_state == 0) {
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91 else if (s.charAt(i) == '%') {
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92 if (i < length - 1) {
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93 if (s.charAt(i + 1) == '%') {
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99 throw new java.lang.IllegalArgumentException();
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101 pre = pre + s.charAt(i);
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104 while (parse_state == 1) {
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107 else if (s.charAt(i) == ' ')
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109 else if (s.charAt(i) == '-')
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111 else if (s.charAt(i) == '+')
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113 else if (s.charAt(i) == '0')
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114 leading_zeroes = true;
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115 else if (s.charAt(i) == '#')
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123 while (parse_state == 2) {
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126 else if ('0' <= s.charAt(i) && s.charAt(i) <= '9') {
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127 width = width * 10 + s.charAt(i) - '0';
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129 } else if (s.charAt(i) == '.') {
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136 while (parse_state == 3) {
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139 else if ('0' <= s.charAt(i) && s.charAt(i) <= '9') {
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140 precision = precision * 10 + s.charAt(i) - '0';
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145 if (parse_state == 4) {
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153 post = s.substring(i, length);
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157 * prints a formatted number following printf conventions
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158 * @param s a PrintStream
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159 * @param fmt the format string
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160 * @param x the double to print
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163 public static void print(java.io.PrintStream s, String fmt, double x) {
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164 s.print(new Format(fmt).form(x));
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168 * prints a formatted number following printf conventions
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169 * @param s a PrintStream
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170 * @param fmt the format string
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171 * @param x the long to print
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173 public static void print(java.io.PrintStream s, String fmt, long x) {
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174 s.print(new Format(fmt).form(x));
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178 * prints a formatted number following printf conventions
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179 * @param s a PrintStream
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180 * @param fmt the format string
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181 * @param x the character to
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184 public static void print(java.io.PrintStream s, String fmt, char x) {
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185 s.print(new Format(fmt).form(x));
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189 * prints a formatted number following printf conventions
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190 * @param s a PrintStream, fmt the format string
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191 * @param x a string that represents the digits to print
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194 public static void print(java.io.PrintStream s, String fmt, String x) {
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195 s.print(new Format(fmt).form(x));
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199 * Converts a string of digits (decimal, octal or hex) to an integer
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200 * @param s a string
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201 * @return the numeric value of the prefix of s representing a base 10 integer
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204 public static int atoi(String s) {
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205 return (int)atol(s);
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209 * Converts a string of digits (decimal, octal or hex) to a long integer
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210 * @param s a string
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211 * @return the numeric value of the prefix of s representing a base 10 integer
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214 public static long atol(String s) {
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217 while (i < s.length() && Character.isWhitespace(s.charAt(i)))
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219 if (i < s.length() && s.charAt(i) == '0') {
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220 if (i + 1 < s.length() && (s.charAt(i + 1) == 'x' || s.charAt(i + 1) == 'X'))
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221 return parseLong(s.substring(i + 2), 16);
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223 return parseLong(s, 8);
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225 return parseLong(s, 10);
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228 private static long parseLong(String s, int base) {
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233 while (i < s.length() && Character.isWhitespace(s.charAt(i)))
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235 if (i < s.length() && s.charAt(i) == '-') {
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238 } else if (i < s.length() && s.charAt(i) == '+') {
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241 while (i < s.length()) {
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242 char ch = s.charAt(i);
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243 if ('0' <= ch && ch < '0' + base)
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244 r = r * base + ch - '0';
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245 else if ('A' <= ch && ch < 'A' + base - 10)
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246 r = r * base + ch - 'A' + 10 ;
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247 else if ('a' <= ch && ch < 'a' + base - 10)
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248 r = r * base + ch - 'a' + 10 ;
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257 * Converts a string of digits to an double
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258 * @param s a string
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261 public static double atof(String s) {
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264 double r = 0; // integer part
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265 double f = 0; // fractional part
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266 double p = 1; // exponent of fractional part
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267 int state = 0; // 0 = int part, 1 = frac part
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269 while (i < s.length() && Character.isWhitespace(s.charAt(i)))
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271 if (i < s.length() && s.charAt(i) == '-') {
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274 } else if (i < s.length() && s.charAt(i) == '+') {
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277 while (i < s.length()) {
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278 char ch = s.charAt(i);
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279 if ('0' <= ch && ch <= '9') {
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281 r = r * 10 + ch - '0';
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282 else if (state == 1) {
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284 r = r + p * (ch - '0');
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286 } else if (ch == '.') {
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291 } else if (ch == 'e' || ch == 'E') {
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292 long e = (int)parseLong(s.substring(i + 1), 10);
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293 return sign * r * Math.pow(10, e);
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302 * Formats a double into a string (like sprintf in C)
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303 * @param x the number to format
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304 * @return the formatted string
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305 * @exception IllegalArgumentException if bad argument
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308 public String form(double x) {
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318 r = fixed_format(x);
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319 else if (fmt == 'e' || fmt == 'E' || fmt == 'g' || fmt == 'G')
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322 throw new java.lang.IllegalArgumentException();
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324 return pad(sign(s, r));
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328 * Formats a long integer into a string (like sprintf in C)
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329 * @param x the number to format
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330 * @return the formatted string
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333 public String form(long x) {
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336 if (fmt == 'd' || fmt == 'i') {
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338 r = ("" + x).substring(1);
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344 } else if (fmt == 'o')
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345 r = convert(x, 3, 7, "01234567");
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346 else if (fmt == 'x')
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347 r = convert(x, 4, 15, "0123456789abcdef");
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348 else if (fmt == 'X')
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349 r = convert(x, 4, 15, "0123456789ABCDEF");
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351 throw new java.lang.IllegalArgumentException();
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353 return pad(sign(s, r));
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357 * Formats a character into a string (like sprintf in C)
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358 * @param x the value to format
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359 * @return the formatted string
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362 public String form(char c) {
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364 throw new java.lang.IllegalArgumentException();
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371 * Formats a string into a larger string (like sprintf in C)
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372 * @param x the value to format
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373 * @return the formatted string
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376 public String form(String s) {
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378 throw new java.lang.IllegalArgumentException();
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379 if (precision >= 0)
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380 s = s.substring(0, precision);
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386 * a test stub for the format class
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389 public static void main(String[] a) {
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390 double x = 1.23456789012;
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392 double z = 1.2345e30;
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394 double u = 1.234e-5;
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396 Format.print(System.out, "x = |%f|\n", x);
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397 Format.print(System.out, "u = |%20f|\n", u);
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398 Format.print(System.out, "x = |% .5f|\n", x);
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399 Format.print(System.out, "w = |%20.5f|\n", w);
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400 Format.print(System.out, "x = |%020.5f|\n", x);
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401 Format.print(System.out, "x = |%+20.5f|\n", x);
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402 Format.print(System.out, "x = |%+020.5f|\n", x);
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403 Format.print(System.out, "x = |% 020.5f|\n", x);
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404 Format.print(System.out, "y = |%#+20.5f|\n", y);
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405 Format.print(System.out, "y = |%-+20.5f|\n", y);
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406 Format.print(System.out, "z = |%20.5f|\n", z);
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408 Format.print(System.out, "x = |%e|\n", x);
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409 Format.print(System.out, "u = |%20e|\n", u);
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410 Format.print(System.out, "x = |% .5e|\n", x);
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411 Format.print(System.out, "w = |%20.5e|\n", w);
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412 Format.print(System.out, "x = |%020.5e|\n", x);
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413 Format.print(System.out, "x = |%+20.5e|\n", x);
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414 Format.print(System.out, "x = |%+020.5e|\n", x);
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415 Format.print(System.out, "x = |% 020.5e|\n", x);
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416 Format.print(System.out, "y = |%#+20.5e|\n", y);
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417 Format.print(System.out, "y = |%-+20.5e|\n", y);
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419 Format.print(System.out, "x = |%g|\n", x);
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420 Format.print(System.out, "z = |%g|\n", z);
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421 Format.print(System.out, "w = |%g|\n", w);
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422 Format.print(System.out, "u = |%g|\n", u);
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423 Format.print(System.out, "y = |%.2g|\n", y);
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424 Format.print(System.out, "y = |%#.2g|\n", y);
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426 Format.print(System.out, "d = |%d|\n", d);
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427 Format.print(System.out, "d = |%20d|\n", d);
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428 Format.print(System.out, "d = |%020d|\n", d);
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429 Format.print(System.out, "d = |%+20d|\n", d);
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430 Format.print(System.out, "d = |% 020d|\n", d);
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431 Format.print(System.out, "d = |%-20d|\n", d);
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432 Format.print(System.out, "d = |%20.8d|\n", d);
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433 Format.print(System.out, "d = |%x|\n", d);
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434 Format.print(System.out, "d = |%20X|\n", d);
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435 Format.print(System.out, "d = |%#20x|\n", d);
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436 Format.print(System.out, "d = |%020X|\n", d);
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437 Format.print(System.out, "d = |%20.8x|\n", d);
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438 Format.print(System.out, "d = |%o|\n", d);
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439 Format.print(System.out, "d = |%020o|\n", d);
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440 Format.print(System.out, "d = |%#20o|\n", d);
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441 Format.print(System.out, "d = |%#020o|\n", d);
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442 Format.print(System.out, "d = |%20.12o|\n", d);
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444 Format.print(System.out, "s = |%-20s|\n", "Hello");
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445 Format.print(System.out, "s = |%-20c|\n", '!');
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447 // regression test to confirm fix of reported bugs
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449 Format.print(System.out, "|%i|\n", Long.MIN_VALUE);
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451 Format.print(System.out, "|%6.2e|\n", 0.0);
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452 Format.print(System.out, "|%6.2g|\n", 0.0);
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454 Format.print(System.out, "|%6.2f|\n", 9.99);
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455 Format.print(System.out, "|%6.2f|\n", 9.999);
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457 Format.print(System.out, "|%6.0f|\n", 9.999);
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460 private static String repeat(char c, int n) {
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463 StringBuffer s = new StringBuffer(n);
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464 for (int i = 0; i < n; i++)
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466 return s.toString();
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469 private static String convert(long x, int n, int m, String d) {
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474 r = d.charAt((int)(x & m)) + r;
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480 private String pad(String r) {
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481 String p = repeat(' ', width - r.length());
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483 return pre + r + p + post;
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485 return pre + p + r + post;
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488 private String sign(int s, String r) {
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495 else if (show_space)
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498 if (fmt == 'o' && alternate && r.length() > 0 && r.charAt(0) != '0')
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500 else if (fmt == 'x' && alternate)
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502 else if (fmt == 'X' && alternate)
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506 if (leading_zeroes)
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508 else if ((fmt == 'd' || fmt == 'i' || fmt == 'x' || fmt == 'X' || fmt == 'o')
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512 return p + repeat('0', w - p.length() - r.length()) + r;
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515 private String fixed_format(double d) {
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516 boolean removeTrailing
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517 = (fmt == 'G' || fmt == 'g') && !alternate;
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518 // remove trailing zeroes and decimal point
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520 if (d > 0x7FFFFFFFFFFFFFFFL)
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521 return exp_format(d);
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522 if (precision == 0)
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523 return (long)(d + 0.5) + (removeTrailing ? "" : ".");
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525 long whole = (long)d;
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526 double fr = d - whole; // fractional part
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527 if (fr >= 1 || fr < 0)
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528 return exp_format(d);
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531 String leading_zeroes = "";
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532 for (int i = 1; i <= precision && factor <= 0x7FFFFFFFFFFFFFFFL; i++) {
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534 leading_zeroes = leading_zeroes + "0";
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536 long l = (long) (factor * fr + 0.5);
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542 String z = leading_zeroes + l;
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543 z = "." + z.substring(z.length() - precision, z.length());
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545 if (removeTrailing) {
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546 int t = z.length() - 1;
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547 while (t >= 0 && z.charAt(t) == '0')
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549 if (t >= 0 && z.charAt(t) == '.')
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551 z = z.substring(0, t + 1);
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557 private String exp_format(double d) {
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574 if ((fmt == 'g' || fmt == 'G') && e >= -4 && e < precision)
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575 return fixed_format(d);
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578 f = f + fixed_format(d);
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580 if (fmt == 'e' || fmt == 'g')
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594 return f + p.substring(p.length() - 3, p.length());
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598 private int precision;
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599 private String pre;
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600 private String post;
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601 private boolean leading_zeroes;
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602 private boolean show_plus;
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603 private boolean alternate;
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604 private boolean show_space;
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605 private boolean left_align;
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606 private char fmt; // one of cdeEfgGiosxXos
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