Mega Code Archive
Prints messages formatted for a specific line width
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/*
* $RCSfile: MsgPrinter.java,v $
* $Revision: 1.1 $
* $Date: 2005/02/11 05:02:26 $
* $State: Exp $
*
* Class: MsgPrinter
*
* Description: Prints messages formatted for a specific
* line width.
*
*
*
* COPYRIGHT:
*
* This software module was originally developed by Raphaël Grosbois and
* Diego Santa Cruz (Swiss Federal Institute of Technology-EPFL); Joel
* Askelöf (Ericsson Radio Systems AB); and Bertrand Berthelot, David
* Bouchard, Félix Henry, Gerard Mozelle and Patrice Onno (Canon Research
* Centre France S.A) in the course of development of the JPEG2000
* standard as specified by ISO/IEC 15444 (JPEG 2000 Standard). This
* software module is an implementation of a part of the JPEG 2000
* Standard. Swiss Federal Institute of Technology-EPFL, Ericsson Radio
* Systems AB and Canon Research Centre France S.A (collectively JJ2000
* Partners) agree not to assert against ISO/IEC and users of the JPEG
* 2000 Standard (Users) any of their rights under the copyright, not
* including other intellectual property rights, for this software module
* with respect to the usage by ISO/IEC and Users of this software module
* or modifications thereof for use in hardware or software products
* claiming conformance to the JPEG 2000 Standard. Those intending to use
* this software module in hardware or software products are advised that
* their use may infringe existing patents. The original developers of
* this software module, JJ2000 Partners and ISO/IEC assume no liability
* for use of this software module or modifications thereof. No license
* or right to this software module is granted for non JPEG 2000 Standard
* conforming products. JJ2000 Partners have full right to use this
* software module for his/her own purpose, assign or donate this
* software module to any third party and to inhibit third parties from
* using this software module for non JPEG 2000 Standard conforming
* products. This copyright notice must be included in all copies or
* derivative works of this software module.
*
* Copyright (c) 1999/2000 JJ2000 Partners.
*
*
*
*/
import java.io.*;
/**
* This utility class formats messages to the specified line width, by
* inserting line-breaks between words, and printing the resulting
* lines.
* */
public class MsgPrinter {
/** The line width to use */
public int lw;
/** Signals that a newline was found */
private static final int IS_NEWLINE = -2;
/** Signals that the end-of-string was reached */
private static final int IS_EOS = -1;
/**
* Creates a new message printer with the specified line width and
* with the default locale.
*
* @param linewidth The line width for which to format (in
* characters)
*
*
* */
public MsgPrinter(int linewidth) {
lw = linewidth;
}
/**
* Returns the line width that is used for formatting.
*
* @return The line width used for formatting
*
*
* */
public int getLineWidth() {
return lw;
}
/**
* Sets the line width to the specified value. This new value will
* be used in subsequent calls to the print() message.
*
* @param linewidth The new line width to use (in cahracters)
*
*
* */
public void setLineWidth(int linewidth) {
if (linewidth <1) {
throw new IllegalArgumentException();
}
lw = linewidth;
}
/**
* Formats the message to print in the current line width, by
* breaking the message into lines between words. The number of
* spaces to indent the first line is specified by 'flind' and the
* number of spaces to indent each of the following lines is
* specified by 'ind'. Newlines in 'msg' are respected. A newline is
* always printed at the end.
*
* @param out Where to print the message.
*
* @param flind The indentation for the first line.
*
* @param ind The indentation for the other lines.
*
* @param msg The message to format and print.
*
*
* */
public void print(PrintWriter out, int flind, int ind,
String msg) {
int start,end,pend,efflw,lind,i;
start = 0;
end = 0;
pend = 0;
efflw = lw-flind;
lind = flind;
while ((end = nextLineEnd(msg,pend)) != IS_EOS) {
if (end == IS_NEWLINE) { // Forced line break
for (i=0; i<lind; i++) {
out.print(" ");
}
out.println(msg.substring(start,pend));
if (nextWord(msg,pend) == msg.length()) {
// Traling newline => print it and done
out.println("");
start = pend;
break;
}
}
else {
if (efflw > end-pend) { // Room left on current line
efflw -= end-pend;
pend = end;
continue;
}
else { // Filled-up current line => print it
for (i=0; i<lind; i++) {
out.print(" ");
}
if (start == pend) { // Word larger than line width
// Print anyways
out.println(msg.substring(start,end));
pend = end;
}
else {
out.println(msg.substring(start,pend));
}
}
}
// Initialize for next line
lind = ind;
efflw = lw-ind;
start = nextWord(msg,pend);
pend = start;
if (start == IS_EOS) {
break; // Did all the string
}
}
if (pend != start) { // Part of a line left => print it
for (i=0; i<lind; i++) {
out.print(" ");
}
out.println(msg.substring(start,pend));
}
}
/**
* Returns the index of the last character of the next word, plus 1, or
* IS_NEWLINE if a newline character is encountered before the next word,
* or IS_EOS if the end of the string is ecnounterd before the next
* word. The method first skips all whitespace characters at or after
* 'from', except newlines. If a newline is found IS_NEWLINE is
* returned. Then it skips all non-whitespace characters and returns the
* position of the last non-whitespace character, plus 1. The returned
* index may be greater than the last valid index in the tsring, but it is
* always suitable to be used in the String.substring() method.
*
* <P>Non-whitespace characters are defined as in the
* Character.isWhitespace method (that method is used).
*
* @param str The string to parse
*
* @param from The index of the first position to search from
*
* @return The index of the last character in the next word, plus 1,
* IS_NEWLINE, or IS_EOS if there are no more words.
*
*
* */
private int nextLineEnd(String str, int from) {
final int len = str.length();
char c = '\0';
// First skip all whitespace, except new line
while (from < len && (c = str.charAt(from)) != '\n' &&
Character.isWhitespace(c)) {
from++;
}
if (c == '\n') {
return IS_NEWLINE;
}
if (from >= len) {
return IS_EOS;
}
// Now skip word characters
while (from < len && !Character.isWhitespace(str.charAt(from))) {
from++;
}
return from;
}
/**
* Returns the position of the first character in the next word, starting
* from 'from', if a newline is encountered first then the index of the
* newline character plus 1 is returned. If the end of the string is
* encountered then IS_EOS is returned. Words are defined as any
* concatenation of 1 or more characters which are not
* whitespace. Whitespace characters are those for which
* Character.isWhitespace() returns true (that method is used).
*
* <P>Non-whitespace characters are defined as in the
* Character.isWhitespace method (that method is used).
*
* @param str The string to parse
*
* @param from The index where to start parsing
*
* @return The index of the first character of the next word, or the index
* of the newline plus 1, or IS_EOS.
*
*
* */
private int nextWord(String str, int from) {
final int len = str.length();
char c = '\0';
// First skip all whitespace, but new lines
while (from < len && (c = str.charAt(from)) != '\n' &&
Character.isWhitespace(c)) {
from++;
}
if (from >= len) {
return IS_EOS;
}
else if (c == '\n') {
return from+1;
}
else {
return from;
}
}
}
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