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v_sentence.c

/*-
 * Copyright (c) 1992, 1993, 1994
 *    The Regents of the University of California.  All rights reserved.
 * Copyright (c) 1992, 1993, 1994, 1995, 1996
 *    Keith Bostic.  All rights reserved.
 *
 * See the LICENSE file for redistribution information.
 */

#include "config.h"

#ifndef lint
static const char sccsid[] = "@(#)v_sentence.c  10.7 (Berkeley) 3/6/96";
#endif /* not lint */

#include <sys/types.h>
#include <sys/queue.h>
#include <sys/time.h>

#include <bitstring.h>
#include <ctype.h>
#include <limits.h>
#include <stdio.h>

#include "../common/common.h"
#include "vi.h"

/*
 * !!!
 * In historic vi, a sentence was delimited by a '.', '?' or '!' character
 * followed by TWO spaces or a newline.  One or more empty lines was also
 * treated as a separate sentence.  The Berkeley documentation for historical
 * vi states that any number of ')', ']', '"' and '\'' characters can be
 * between the delimiter character and the spaces or end of line, however,
 * the historical implementation did not handle additional '"' characters.
 * We follow the documentation here, not the implementation.
 *
 * Once again, historical vi didn't do sentence movements associated with
 * counts consistently, mostly in the presence of lines containing only
 * white-space characters.
 *
 * This implementation also permits a single tab to delimit sentences, and
 * treats lines containing only white-space characters as empty lines.
 * Finally, tabs are eaten (along with spaces) when skipping to the start
 * of the text following a "sentence".
 */

/*
 * v_sentencef -- [count])
 *    Move forward count sentences.
 *
 * PUBLIC: int v_sentencef __P((SCR *, VICMD *));
 */
int
v_sentencef(sp, vp)
      SCR *sp;
      VICMD *vp;
{
      enum { BLANK, NONE, PERIOD } state;
      VCS cs;
      size_t len;
      u_long cnt;

      cs.cs_lno = vp->m_start.lno;
      cs.cs_cno = vp->m_start.cno;
      if (cs_init(sp, &cs))
            return (1);

      cnt = F_ISSET(vp, VC_C1SET) ? vp->count : 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 (cs.cs_flags == CS_EMP || cs.cs_flags == 0 && isblank(cs.cs_ch)) {
            if (cs_fblank(sp, &cs))
                  return (1);
            if (--cnt == 0) {
                  if (vp->m_start.lno != cs.cs_lno ||
                      vp->m_start.cno != cs.cs_cno)
                        goto okret;
                  return (1);
            }
      }

      for (state = NONE;;) {
            if (cs_next(sp, &cs))
                  return (1);
            if (cs.cs_flags == CS_EOF)
                  break;
            if (cs.cs_flags == CS_EOL) {
                  if ((state == PERIOD || state == BLANK) && --cnt == 0) {
                        if (cs_next(sp, &cs))
                              return (1);
                        if (cs.cs_flags == 0 &&
                            isblank(cs.cs_ch) && cs_fblank(sp, &cs))
                              return (1);
                        goto okret;
                  }
                  state = NONE;
                  continue;
            }
            if (cs.cs_flags == CS_EMP) {  /* An EMP is two sentences. */
                  if (--cnt == 0)
                        goto okret;
                  if (cs_fblank(sp, &cs))
                        return (1);
                  if (--cnt == 0)
                        goto okret;
                  state = NONE;
                  continue;
            }
            switch (cs.cs_ch) {
            case '.':
            case '?':
            case '!':
                  state = PERIOD;
                  break;
            case ')':
            case ']':
            case '"':
            case '\'':
                  if (state != PERIOD)
                        state = NONE;
                  break;
            case '\t':
                  if (state == PERIOD)
                        state = BLANK;
                  /* FALLTHROUGH */
            case ' ':
                  if (state == PERIOD) {
                        state = BLANK;
                        break;
                  }
                  if (state == BLANK && --cnt == 0) {
                        if (cs_fblank(sp, &cs))
                              return (1);
                        goto okret;
                  }
                  /* FALLTHROUGH */
            default:
                  state = NONE;
                  break;
            }
      }

      /* EOF is a movement sink, but it's an error not to have moved. */
      if (vp->m_start.lno == cs.cs_lno && vp->m_start.cno == cs.cs_cno) {
            v_eof(sp, NULL);
            return (1);
      }

okret:      vp->m_stop.lno = cs.cs_lno;
      vp->m_stop.cno = cs.cs_cno;

      /*
       * !!!
       * Historic, uh, features, yeah, that's right, call 'em features.
       * If the starting and ending cursor positions are at the first
       * column in their lines, i.e. the movement is cutting entire lines,
       * the buffer is in line mode, and the ending position is the last
       * character of the previous line.  Note check to make sure that
       * it's not within a single line.
       *
       * Non-motion commands move to the end of the range.  Delete and
       * yank stay at the start.  Ignore others.  Adjust the end of the
       * range for motion commands.
       */
      if (ISMOTION(vp)) {
            if (vp->m_start.cno == 0 &&
                (cs.cs_flags != 0 || vp->m_stop.cno == 0)) {
                  if (vp->m_start.lno < vp->m_stop.lno) {
                        if (db_get(sp,
                            --vp->m_stop.lno, DBG_FATAL, NULL, &len))
                              return (1);
                        vp->m_stop.cno = len ? len - 1 : 0;
                  }
                  F_SET(vp, VM_LMODE);
            } else
                  --vp->m_stop.cno;
            vp->m_final = vp->m_start;
      } else
            vp->m_final = vp->m_stop;
      return (0);
}

/*
 * v_sentenceb -- [count](
 *    Move backward count sentences.
 *
 * PUBLIC: int v_sentenceb __P((SCR *, VICMD *));
 */
int
v_sentenceb(sp, vp)
      SCR *sp;
      VICMD *vp;
{
      VCS cs;
      recno_t slno;
      size_t len, scno;
      u_long cnt;
      int last;

      /*
       * !!!
       * Historic vi permitted the user to hit SOF repeatedly.
       */
      if (vp->m_start.lno == 1 && vp->m_start.cno == 0)
            return (0);

      cs.cs_lno = vp->m_start.lno;
      cs.cs_cno = vp->m_start.cno;
      if (cs_init(sp, &cs))
            return (1);

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

      /*
       * !!!
       * In empty lines, skip to the previous non-white-space character.
       * If in text, skip to the prevous white-space character.  Believe
       * it or not, in the paragraph:
       *    ab cd.
       *    AB CD.
       * if the cursor is on the 'A' or 'B', ( moves to the 'a'.  If it
       * is on the ' ', 'C' or 'D', it moves to the 'A'.  Yes, Virginia,
       * Berkeley was once a major center of drug activity.
       */
      if (cs.cs_flags == CS_EMP) {
            if (cs_bblank(sp, &cs))
                  return (1);
            for (;;) {
                  if (cs_prev(sp, &cs))
                        return (1);
                  if (cs.cs_flags != CS_EOL)
                        break;
            }
      } else if (cs.cs_flags == 0 && !isblank(cs.cs_ch))
            for (;;) {
                  if (cs_prev(sp, &cs))
                        return (1);
                  if (cs.cs_flags != 0 || isblank(cs.cs_ch))
                        break;
            }

      for (last = 0;;) {
            if (cs_prev(sp, &cs))
                  return (1);
            if (cs.cs_flags == CS_SOF)    /* SOF is a movement sink. */
                  break;
            if (cs.cs_flags == CS_EOL) {
                  last = 1;
                  continue;
            }
            if (cs.cs_flags == CS_EMP) {
                  if (--cnt == 0)
                        goto ret;
                  if (cs_bblank(sp, &cs))
                        return (1);
                  last = 0;
                  continue;
            }
            switch (cs.cs_ch) {
            case '.':
            case '?':
            case '!':
                  if (!last || --cnt != 0) {
                        last = 0;
                        continue;
                  }

ret:              slno = cs.cs_lno;
                  scno = cs.cs_cno;

                  /*
                   * Move to the start of the sentence, skipping blanks
                   * and special characters.
                   */
                  do {
                        if (cs_next(sp, &cs))
                              return (1);
                  } while (!cs.cs_flags &&
                      (cs.cs_ch == ')' || cs.cs_ch == ']' ||
                      cs.cs_ch == '"' || cs.cs_ch == '\''));
                  if ((cs.cs_flags || isblank(cs.cs_ch)) &&
                      cs_fblank(sp, &cs))
                        return (1);

                  /*
                   * If it was ".  xyz", with the cursor on the 'x', or
                   * "end.  ", with the cursor in the spaces, or the
                   * beginning of a sentence preceded by an empty line,
                   * we can end up where we started.  Fix it.
                   */
                  if (vp->m_start.lno != cs.cs_lno ||
                      vp->m_start.cno != cs.cs_cno)
                        goto okret;

                  /*
                   * Well, if an empty line preceded possible blanks
                   * and the sentence, it could be a real sentence.
                   */
                  for (;;) {
                        if (cs_prev(sp, &cs))
                              return (1);
                        if (cs.cs_flags == CS_EOL)
                              continue;
                        if (cs.cs_flags == 0 && isblank(cs.cs_ch))
                              continue;
                        break;
                  }
                  if (cs.cs_flags == CS_EMP)
                        goto okret;

                  /* But it wasn't; try again. */
                  ++cnt;
                  cs.cs_lno = slno;
                  cs.cs_cno = scno;
                  last = 0;
                  break;
            case '\t':
                  last = 1;
                  break;
            default:
                  last =
                      cs.cs_flags == CS_EOL || isblank(cs.cs_ch) ||
                      cs.cs_ch == ')' || cs.cs_ch == ']' ||
                      cs.cs_ch == '"' || cs.cs_ch == '\'' ? 1 : 0;
            }
      }

okret:      vp->m_stop.lno = cs.cs_lno;
      vp->m_stop.cno = cs.cs_cno;

      /*
       * !!!
       * If the starting and stopping cursor positions are at the first
       * columns in the line, i.e. the movement is cutting an entire line,
       * the buffer is in line mode, and the starting position is the last
       * character of the previous line.
       *
       * All commands move to the end of the range.  Adjust the start of
       * the range for motion commands.
       */
      if (ISMOTION(vp))
            if (vp->m_start.cno == 0 &&
                (cs.cs_flags != 0 || vp->m_stop.cno == 0)) {
                  if (db_get(sp,
                      --vp->m_start.lno, DBG_FATAL, NULL, &len))
                        return (1);
                  vp->m_start.cno = len ? len - 1 : 0;
                  F_SET(vp, VM_LMODE);
            } else
                  --vp->m_start.cno;
      vp->m_final = vp->m_stop;
      return (0);
}

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