BSD 4_4 release

[unix-history] / usr / src / contrib / nvi / nvi / vi / v_sentence.c

/*-
* Copyright (c) 1992, 1993
*      The Regents of the University of California.  All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
*    must display the following acknowledgement:
*      This product includes software developed by the University of
*      California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
*    may be used to endorse or promote products derived from this software
*    without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/

#ifndef lint
static char sccsid[] = "@(#)v_sentence.c        8.1 (Berkeley) 6/9/93";
#endif /* not lint */

#include <sys/types.h>

#include "vi.h"
#include "vcmd.h"

/*
* Sentences are sequences of characters terminated by a period followed
* by at least two spaces or a newline.
* 
* Historical vi mishandled lines with only white-space characters.  Forward
* sentences treated them as part of the current sentence, backward sentences
* treated them as different sentences.  This implementation treats lines with
* only white-space characters and empty lines as sentence delimiters, not
* sentences, in both directions.
*/

#define EATBLANK(sp)                                                    \
       while (getc_next(sp, ep, FORWARD, &ch) &&                       \
           (ch == EMPTYLINE || ch == ' ' || ch == '\t'))

#define ISSPACE(ch)                                                     \
       (ch == EMPTYLINE || ch == ' ' || ch == '\t')

/*
* v_sentencef -- [count])
*      Move forward count sentences.
*/
int
v_sentencef(sp, ep, vp, fm, tm, rp)
       SCR *sp;
       EXF *ep;
       VICMDARG *vp;
       MARK *fm, *tm, *rp;
{
       enum { NONE, PERIOD, BLANK } state;
       int ch;
       u_long cnt;

       cnt = F_ISSET(vp, VC_C1SET) ? vp->count : 1;

       if (getc_init(sp, ep, fm, &ch))
               return (1);

       /*
        * If in white-space, the next start of sentence counts as one.
        * This may not handle "  .  " correctly, but it's real unclear
        * what correctly means in that case.
        */
       if (ISSPACE(ch)) {
               EATBLANK(sp);
               if (--cnt == 0) {
                       getc_set(sp, ep, rp);
                       if (fm->lno != rp->lno || fm->cno != rp->cno)
                               return (0);
                       v_eof(sp, ep, NULL);
                       return (1);
               }
       }
       for (state = NONE; getc_next(sp, ep, FORWARD, &ch);)
               switch(ch) {
               case EMPTYLINE:
                       if ((state == PERIOD || state == BLANK) && --cnt == 0) {
                               EATBLANK(sp);
                               getc_set(sp, ep, rp);
                               return (0);
                       }
                       state = NONE;
                       break;
               case '.':
               case '?':
               case '!':
                       state = PERIOD;
                       break;
               case ' ':
               case '\t':
                       if (state == PERIOD) {
                               state = BLANK;
                               break;
                       }
                       if (state == BLANK && --cnt == 0) {
                               EATBLANK(sp);
                               getc_set(sp, ep, rp);
                               return (0);
                       }
                       break;
               default:
                       state = NONE;
                       break;
               }

       /* EOF is a movement sink. */
       getc_set(sp, ep, rp);
       if (fm->lno != rp->lno || fm->cno != rp->cno)
               return (0);

       v_eof(sp, ep, NULL);
       return (1);
}

#undef  EATBLANK
#define EATBLANK(sp)                                                    \
       while (getc_next(sp, ep, BACKWARD, &ch) &&                      \
           (ch == EMPTYLINE || ch == ' ' || ch == '\t'))

/*
* v_sentenceb -- [count])
*      Move forward count sentences.
*/
int
v_sentenceb(sp, ep, vp, fm, tm, rp)
       SCR *sp;
       EXF *ep;
       VICMDARG *vp;
       MARK *fm, *tm, *rp;
{
       int ch, last1, last2;
       u_long cnt;

       if (fm->lno == 1 && fm->cno == 0) {
               v_sof(sp, NULL);
               return (1);
       }

       cnt = F_ISSET(vp, VC_C1SET) ? vp->count : 1;

       if (getc_init(sp, ep, fm, &ch))
               return (1);

       /*
        * Make ".  xxx" with the cursor on the 'x', and "xxx.  ", with the
        * cursor in the spaces, work.
        */
       if (getc_next(sp, ep, BACKWARD, &ch) && ISSPACE(ch))
               EATBLANK(sp);

       for (last1 = last2 = 'a'; getc_next(sp, ep, BACKWARD, &ch);) {
               if ((ch == '.' || ch == '?' || ch == '!') &&
                   ISSPACE(last1) && ISSPACE(last2) && --cnt == 0) {
                       while (getc_next(sp, ep, FORWARD, &ch) && ISSPACE(ch));
                       getc_set(sp, ep, rp);
                       return (0);
               }
               last2 = last1;
               last1 = ch;
       }

       /* SOF is a movement sink. */
       getc_set(sp, ep, rp);
       return (0);
}