petidomo/libtext/wordwrap.c

/*
   $Source$
   $Revision$

   Copyright (C) 2000 by CyberSolutions GmbH, Germany.

   This file is part of OpenPetidomo.

   OpenPetidomo 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 2, or (at your option)
   any later version.

   OpenPetidomo 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 OpenPetidomo; see the file COPYING. If not, write to
   the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
   Boston, MA 02111-1307, USA.
*/

#include <ctype.h>
#include "text.h"

/* Wrap a text buffer at a certain column.

   This routine wraps all lines in a text buffer that are longer than
   the specified limit. Paragraphs will remain untouched. Paragraphs
   are separated by an empty line -- a line containing only a line
   feed (\\n) that is.

   AUTHOR: Peter Simons <simons@rhein.de>

 */

void
text_wordwrap(char *         buffer    /* Pointer to text buffer. */,
	      unsigned int   line_len  /* Maximum line length. */)
{
    char *         p;
    char *         q;
    char *         lastbreak;
    unsigned int   linepos;

    /* First remove all single occurances of a '\n' and crunch
       multiple blanks to one. */

    for (p = q = buffer; *p != '\0'; ) {
	if (*p == '\n') {
	    if (p[1] == '\n') {
		*q++ = *p++;
		*q++ = *p++;
	    }
	    else {
		*q++ = ' ';
		p++;
	    }
	} else if (isspace((int)*p)) {
	    if (isspace((int)q[-1]))
	      p++;
	    else
	      *q++ = *p++;
	}
	else
	  *q++ = *p++;
    }

    /* Wrap the text. */

    for (p = buffer, lastbreak = NULL, linepos = 1; *p != '\0'; p++, linepos++) {
	if (*p == '\n') {
	    linepos = 0;
	    lastbreak = NULL;
	}
	else if (isspace((int)*p)) {
	    if (linepos <= line_len) {
		lastbreak = p;
	    }
	    else {
		/* Wrap it. */
		if (lastbreak) {
		    *lastbreak = '\n';
		    p = lastbreak;
		    linepos = 0;
		    lastbreak = NULL;
		}
		else {
		    /* Word is too long. <shrug> */
		    *p = '\n';
		    linepos = 0;
		    lastbreak = NULL;
		}
	    }
	}
    }

    if (linepos >= line_len) {
	/* Wrap it one last time. */
	if (lastbreak) {
	    *lastbreak = '\n';
	    p = lastbreak;
	    linepos = 0;
	    lastbreak = NULL;
	}
    }
}