FileDocCategorySizeDatePackage
EnTab.javaAPI DocExample3594Sun Feb 22 15:21:44 GMT 2004None

EnTab

public class EnTab extends Object
EnTab: replace blanks by tabs and blanks. Transmuted from K&R Software Tools book into C. Transmuted again, years later, into Java. Totally rewritten to be line-at-a-time instead of char-at-a-time.
author
Ian F. Darwin, http://www.darwinsys.com/
version
$Id: EnTab.java,v 1.11 2004/02/22 21:21:44 ian Exp $

Fields Summary
protected Tabs
tabs
The Tabs (tab logic handler)
Constructors Summary
public EnTab(int n)
Constructor: just save the tab values.

param
n The number of spaces each tab is to replace.

		tabs = new Tabs(n);
public EnTab()

		tabs = new Tabs();
Methods Summary
public voidentab(java.io.BufferedReader is, java.io.PrintWriter out)
entab: process one file, replacing blanks with tabs.

param
is A BufferedReader opened to the file to be read.
param
out a PrintWriter to send the output to.

		String line;
		int c, col = 0, newcol;

		// main loop: process entire file one line at a time.
		while ((line = is.readLine()) != null) {
			out.println(entabLine(line));
		}
public voidentab(java.io.BufferedReader is, java.io.PrintStream out)
entab: process one file, replacing blanks with tabs.

param
is A BufferedReader opened to the file to be read.
param
out A PrintStream to write the output to.

		entab(is, new PrintWriter(out));
public java.lang.StringentabLine(java.lang.String line)
entabLine: process one line, replacing blanks with tabs.

param
line - the string to be processed

		int N = line.length(), outCol = 0;
		StringBuffer sb = new StringBuffer();
		char ch;
		int consumedSpaces = 0;
		
		for (int inCol = 0; inCol < N; inCol++) {
			ch = line.charAt(inCol);
			// If we get a space, consume it, don't output it.
			// If this takes us to a tab stop, output a tab character.
			if (ch == ' ") {
				Debug.println("space", "Got space at " + inCol);
				if (!tabs.isTabStop(inCol)) {
					consumedSpaces++;
				} else {
					Debug.println("tab", "Got a Tab Stop " + inCol);
					sb.append('\t");
					outCol += consumedSpaces;
					consumedSpaces = 0;
				}
				continue;
			}

			// We're at a non-space; if we're just past a tab stop, we need
			// to put the "leftover" spaces back out, since we consumed
			// them above.
			while (inCol-1 > outCol) {
				Debug.println("pad", "Padding space at " + inCol);
				sb.append(' ");
				outCol++;
			}

			// Now we have a plain character to output.
			sb.append(ch);
			outCol++;

		}
		// If line ended with trailing (or only!) spaces, preserve them.
		for (int i = 0; i < consumedSpaces; i++) {
			Debug.println("trail", "Padding space at end # " + i);
			sb.append(' ");
		}
		return sb.toString();
public intgetTabSpacing()
Delegate tab spacing information to tabs.

return

		return tabs.getTabSpacing();
public static voidmain(java.lang.String[] argv)
Main program: just create an EnTab object, and pass the standard input or the named file(s) through it.

		EnTab et = new EnTab(8);
		if (argv.length == 0) // do standard input
			et.entab(
				new BufferedReader(new InputStreamReader(System.in)),
				System.out);
		else
			for (int i = 0; i < argv.length; i++) { // do each file
				et.entab(
					new BufferedReader(new FileReader(argv[i])),
					System.out);
			}