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v_txt.c

/*-
 * Copyright (c) 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_txt.c 10.87 (Berkeley) 10/13/96";
#endif /* not lint */

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

#include <bitstring.h>
#include <ctype.h>
#include <errno.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

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

static int   txt_abbrev __P((SCR *, TEXT *, CHAR_T *, int, int *, int *));
static void  txt_ai_resolve __P((SCR *, TEXT *, int *));
static TEXT *txt_backup __P((SCR *, TEXTH *, TEXT *, u_int32_t *));
static int   txt_dent __P((SCR *, TEXT *, int));
static int   txt_emark __P((SCR *, TEXT *, size_t));
static void  txt_err __P((SCR *, TEXTH *));
static int   txt_fc __P((SCR *, TEXT *, int *));
static int   txt_fc_col __P((SCR *, int, ARGS **));
static int   txt_hex __P((SCR *, TEXT *));
static int   txt_insch __P((SCR *, TEXT *, CHAR_T *, u_int));
static int   txt_isrch __P((SCR *, VICMD *, TEXT *, u_int8_t *));
static int   txt_map_end __P((SCR *));
static int   txt_map_init __P((SCR *));
static int   txt_margin __P((SCR *, TEXT *, TEXT *, int *, u_int32_t));
static void  txt_nomorech __P((SCR *));
static void  txt_Rresolve __P((SCR *, TEXTH *, TEXT *, const size_t));
static int   txt_resolve __P((SCR *, TEXTH *, u_int32_t));
static int   txt_showmatch __P((SCR *, TEXT *));
static void  txt_unmap __P((SCR *, TEXT *, u_int32_t *));

/* Cursor character (space is hard to track on the screen). */
#if defined(DEBUG) && 0
#undef      CH_CURSOR
#define     CH_CURSOR   '+'
#endif

/*
 * v_tcmd --
 *    Fill a buffer from the terminal for vi.
 *
 * PUBLIC: int v_tcmd __P((SCR *, VICMD *, ARG_CHAR_T, u_int));
 */
int
v_tcmd(sp, vp, prompt, flags)
      SCR *sp;
      VICMD *vp;
      ARG_CHAR_T prompt;
      u_int flags;
{
      /* Normally, we end up where we started. */
      vp->m_final.lno = sp->lno;
      vp->m_final.cno = sp->cno;

      /* Initialize the map. */
      if (txt_map_init(sp))
            return (1);

      /* Move to the last line. */
      sp->lno = TMAP[0].lno;
      sp->cno = 0;

      /* Don't update the modeline for now. */
      F_SET(sp, SC_TINPUT_INFO);

      /* Set the input flags. */
      LF_SET(TXT_APPENDEOL |
          TXT_CR | TXT_ESCAPE | TXT_INFOLINE | TXT_MAPINPUT);
      if (O_ISSET(sp, O_ALTWERASE))
            LF_SET(TXT_ALTWERASE);
      if (O_ISSET(sp, O_TTYWERASE))
            LF_SET(TXT_TTYWERASE);

      /* Do the input thing. */
      if (v_txt(sp, vp, NULL, NULL, 0, prompt, 0, 1, flags))
            return (1);

      /* Reenable the modeline updates. */
      F_CLR(sp, SC_TINPUT_INFO);

      /* Clean up the map. */
      if (txt_map_end(sp))
            return (1);

      if (IS_ONELINE(sp))
            F_SET(sp, SC_SCR_REDRAW);     /* XXX */

      /* Set the cursor to the resulting position. */
      sp->lno = vp->m_final.lno;
      sp->cno = vp->m_final.cno;

      return (0);
}

/*
 * txt_map_init
 *    Initialize the screen map for colon command-line input.
 */
static int
txt_map_init(sp)
      SCR *sp;
{
      SMAP *esmp;
      VI_PRIVATE *vip;

      vip = VIP(sp);
      if (!IS_ONELINE(sp)) {
            /*
             * Fake like the user is doing input on the last line of the
             * screen.  This makes all of the scrolling work correctly,
             * and allows us the use of the vi text editing routines, not
             * to mention practically infinite length ex commands.
             *
             * Save the current location.
             */
            vip->sv_tm_lno = TMAP->lno;
            vip->sv_tm_soff = TMAP->soff;
            vip->sv_tm_coff = TMAP->coff;
            vip->sv_t_maxrows = sp->t_maxrows;
            vip->sv_t_minrows = sp->t_minrows;
            vip->sv_t_rows = sp->t_rows;

            /*
             * If it's a small screen, TMAP may be small for the screen.
             * Fix it, filling in fake lines as we go.
             */
            if (IS_SMALL(sp))
                  for (esmp =
                      HMAP + (sp->t_maxrows - 1); TMAP < esmp; ++TMAP) {
                        TMAP[1].lno = TMAP[0].lno + 1;
                        TMAP[1].coff = HMAP->coff;
                        TMAP[1].soff = 1;
                  }

            /* Build the fake entry. */
            TMAP[1].lno = TMAP[0].lno + 1;
            TMAP[1].soff = 1;
            TMAP[1].coff = 0;
            SMAP_FLUSH(&TMAP[1]);
            ++TMAP;

            /* Reset the screen information. */
            sp->t_rows = sp->t_minrows = ++sp->t_maxrows;
      }
      return (0);
}

/*
 * txt_map_end
 *    Reset the screen map for colon command-line input.
 */
static int
txt_map_end(sp)
      SCR *sp;
{
      VI_PRIVATE *vip;
      size_t cnt;

      vip = VIP(sp);
      if (!IS_ONELINE(sp)) {
            /* Restore the screen information. */
            sp->t_rows = vip->sv_t_rows;
            sp->t_minrows = vip->sv_t_minrows;
            sp->t_maxrows = vip->sv_t_maxrows;

            /*
             * If it's a small screen, TMAP may be wrong.  Clear any
             * lines that might have been overwritten.
             */
            if (IS_SMALL(sp)) {
                  for (cnt = sp->t_rows; cnt <= sp->t_maxrows; ++cnt) {
                        (void)sp->gp->scr_move(sp, cnt, 0);
                        (void)sp->gp->scr_clrtoeol(sp);
                  }
                  TMAP = HMAP + (sp->t_rows - 1);
            } else
                  --TMAP;

            /*
             * The map may be wrong if the user entered more than one
             * (logical) line.  Fix it.  If the user entered a whole
             * screen, this will be slow, but we probably don't care.
             */
            if (!O_ISSET(sp, O_LEFTRIGHT))
                  while (vip->sv_tm_lno != TMAP->lno ||
                      vip->sv_tm_soff != TMAP->soff)
                        if (vs_sm_1down(sp))
                              return (1);
      }

      /*
       * Invalidate the cursor and the line size cache, the line never
       * really existed.  This fixes bugs where the user searches for
       * the last line on the screen + 1 and the refresh routine thinks
       * that's where we just were.
       */
      VI_SCR_CFLUSH(vip);
      F_SET(vip, VIP_CUR_INVALID);

      return (0);
}

/*
 * If doing input mapping on the colon command line, may need to unmap
 * based on the command.
 */
#define     UNMAP_TST                                       \
      FL_ISSET(ec_flags, EC_MAPINPUT) && LF_ISSET(TXT_INFOLINE)

/* 
 * Internally, we maintain tp->lno and tp->cno, externally, everyone uses
 * sp->lno and sp->cno.  Make them consistent as necessary.
 */
#define     UPDATE_POSITION(sp, tp) {                             \
      (sp)->lno = (tp)->lno;                                \
      (sp)->cno = (tp)->cno;                                \
}

/*
 * v_txt --
 *    Vi text input.
 *
 * PUBLIC: int v_txt __P((SCR *, VICMD *, MARK *,
 * PUBLIC:    const char *, size_t, ARG_CHAR_T, recno_t, u_long, u_int32_t));
 */
int
v_txt(sp, vp, tm, lp, len, prompt, ai_line, rcount, flags)
      SCR *sp;
      VICMD *vp;
      MARK *tm;         /* To MARK. */
      const char *lp;         /* Input line. */
      size_t len;       /* Input line length. */
      ARG_CHAR_T prompt;      /* Prompt to display. */
      recno_t ai_line;  /* Line number to use for autoindent count. */
      u_long rcount;          /* Replay count. */
      u_int32_t flags;  /* TXT_* flags. */
{
      EVENT ev, *evp;         /* Current event. */
      EVENT fc;         /* File name completion event. */
      GS *gp;
      TEXT *ntp, *tp;         /* Input text structures. */
      TEXT ait;         /* Autoindent text structure. */
      TEXT wmt;         /* Wrapmargin text structure. */
      TEXTH *tiqh;
      VI_PRIVATE *vip;
      abb_t abb;        /* State of abbreviation checks. */
      carat_t carat;          /* State of the "[^0]^D" sequences. */
      quote_t quote;          /* State of quotation. */
      size_t owrite, insert;  /* Temporary copies of TEXT fields. */
      size_t margin;          /* Wrapmargin value. */
      size_t rcol;            /* 0-N: insert offset in the replay buffer. */
      size_t tcol;            /* Temporary column. */
      u_int32_t ec_flags;     /* Input mapping flags. */
#define     IS_RESTART  0x01  /* Reset the incremental search. */
#define     IS_RUNNING  0x02  /* Incremental search turned on. */
      u_int8_t is_flags;
      int abcnt, ab_turnoff;  /* Abbreviation character count, switch. */
      int filec_redraw; /* Redraw after the file completion routine. */
      int hexcnt;       /* Hex character count. */
      int showmatch;          /* Showmatch set on this character. */
      int wm_set, wm_skip;    /* Wrapmargin happened, blank skip flags. */
      int max, tmp;
      char *p;
      static int intro = 1;   /* Introduce insert mode */

      gp = sp->gp;
      vip = VIP(sp);

      if (!prompt) {
          vigor_maybe_confirm(25, "\"Do you wish to enter insert mode?\"", gp);
          if (intro) {
            intro = 0;
            vigor_comment("\"You have not entered insert mode before.  While you're in insert mode, remember that you need to return to command mode before entering Vigor commands!\"", gp);
          }
      }

      /*
       * Set the input flag, so tabs get displayed correctly
       * and everyone knows that the text buffer is in use.
       */
      F_SET(sp, SC_TINPUT);

      /*
       * Get one TEXT structure with some initial buffer space, reusing
       * the last one if it's big enough.  (All TEXT bookkeeping fields
       * default to 0 -- text_init() handles this.)  If changing a line,
       * copy it into the TEXT buffer.
       */
      tiqh = &sp->tiq;
      if (tiqh->cqh_first != (void *)tiqh) {
            tp = tiqh->cqh_first;
            if (tp->q.cqe_next != (void *)tiqh || tp->lb_len < len + 32) {
                  text_lfree(tiqh);
                  goto newtp;
            }
            tp->ai = tp->insert = tp->offset = tp->owrite = 0;
            if (lp != NULL) {
                  tp->len = len;
                  memmove(tp->lb, lp, len);
            } else
                  tp->len = 0;
      } else {
newtp:            if ((tp = text_init(sp, lp, len, len + 32)) == NULL)
                  return (1);
            CIRCLEQ_INSERT_HEAD(tiqh, tp, q);
      }

      /* Set default termination condition. */
      tp->term = TERM_OK;

      /* Set the starting line, column. */
      tp->lno = sp->lno;
      tp->cno = sp->cno;

      /*
       * Set the insert and overwrite counts.  If overwriting characters,
       * do insertion afterward.  If not overwriting characters, assume
       * doing insertion.  If change is to a mark, emphasize it with an
       * CH_ENDMARK character.
       */
      if (len) {
            if (LF_ISSET(TXT_OVERWRITE)) {
                  tp->owrite = (tm->cno - tp->cno) + 1;
                  tp->insert = (len - tm->cno) - 1;
            } else
                  tp->insert = len - tp->cno;

            if (LF_ISSET(TXT_EMARK) && txt_emark(sp, tp, tm->cno))
                  return (1);
      }

      /*
       * Many of the special cases in text input are to handle autoindent
       * support.  Somebody decided that it would be a good idea if "^^D"
       * and "0^D" deleted all of the autoindented characters.  In an editor
       * that takes single character input from the user, this beggars the
       * imagination.  Note also, "^^D" resets the next lines' autoindent,
       * but "0^D" doesn't.
       *
       * We assume that autoindent only happens on empty lines, so insert
       * and overwrite will be zero.  If doing autoindent, figure out how
       * much indentation we need and fill it in.  Update input column and
       * screen cursor as necessary.
       */
      if (LF_ISSET(TXT_AUTOINDENT) && ai_line != OOBLNO) {
            if (v_txt_auto(sp, ai_line, NULL, 0, tp))
                  return (1);
            tp->cno = tp->ai;
      } else {
            /*
             * The cc and S commands have a special feature -- leading
             * <blank> characters are handled as autoindent characters.
             * Beauty!
             */
            if (LF_ISSET(TXT_AICHARS)) {
                  tp->offset = 0;
                  tp->ai = tp->cno;
            } else
                  tp->offset = tp->cno;
      }

      /* If getting a command buffer from the user, there may be a prompt. */
      if (LF_ISSET(TXT_PROMPT)) {
            tp->lb[tp->cno++] = prompt;
            ++tp->len;
            ++tp->offset;
      }

      /*
       * If appending after the end-of-line, add a space into the buffer
       * and move the cursor right.  This space is inserted, i.e. pushed
       * along, and then deleted when the line is resolved.  Assumes that
       * the cursor is already positioned at the end of the line.  This
       * avoids the nastiness of having the cursor reside on a magical
       * column, i.e. a column that doesn't really exist.  The only down
       * side is that we may wrap lines or scroll the screen before it's
       * strictly necessary.  Not a big deal.
       */
      if (LF_ISSET(TXT_APPENDEOL)) {
            tp->lb[tp->cno] = CH_CURSOR;
            ++tp->len;
            ++tp->insert;
            (void)vs_change(sp, tp->lno, LINE_RESET);
      }

      /*
       * Historic practice is that the wrapmargin value was a distance
       * from the RIGHT-HAND margin, not the left.  It's more useful to
       * us as a distance from the left-hand margin, i.e. the same as
       * the wraplen value.  The wrapmargin option is historic practice.
       * Nvi added the wraplen option so that it would be possible to
       * edit files with consistent margins without knowing the number of
       * columns in the window.
       *
       * XXX
       * Setting margin causes a significant performance hit.  Normally
       * we don't update the screen if there are keys waiting, but we
       * have to if margin is set, otherwise the screen routines don't
       * know where the cursor is.
       *
       * !!!
       * Abbreviated keys were affected by the wrapmargin option in the
       * historic 4BSD vi.  Mapped keys were usually, but sometimes not.
       * See the comment in vi/v_text():set_txt_std for more information.
       *
       * !!!
       * One more special case.  If an inserted <blank> character causes
       * wrapmargin to split the line, the next user entered character is
       * discarded if it's a <space> character.
       */
      wm_set = wm_skip = 0;
      if (LF_ISSET(TXT_WRAPMARGIN))
            if ((margin = O_VAL(sp, O_WRAPMARGIN)) != 0)
                  margin = sp->cols - margin;
            else
                  margin = O_VAL(sp, O_WRAPLEN);
      else
            margin = 0;

      /* Initialize abbreviation checks. */
      abcnt = ab_turnoff = 0;
      abb = F_ISSET(gp, G_ABBREV) &&
          LF_ISSET(TXT_MAPINPUT) ? AB_INWORD : AB_NOTSET;

      /*
       * Set up the dot command.  Dot commands are done by saving the actual
       * characters and then reevaluating them so that things like wrapmargin
       * can change between the insert and the replay.
       *
       * !!!
       * Historically, vi did not remap or reabbreviate replayed input.  (It
       * did beep at you if you changed an abbreviation and then replayed the
       * input.  We're not that compatible.)  We don't have to do anything to
       * avoid remapping, as we're not getting characters from the terminal
       * routines.  Turn the abbreviation check off.
       *
       * XXX
       * It would be nice if we could swallow backspaces and such, but it's
       * not all that easy to do.  What we can do is turn off the common
       * error messages during the replay.  Otherwise, when the user enters
       * an illegal command, e.g., "Ia<erase><erase><erase><erase>b<escape>",
       * and then does a '.', they get a list of error messages after command
       * completion.
       */
      rcol = 0;
      if (LF_ISSET(TXT_REPLAY)) {
            abb = AB_NOTSET;
            LF_CLR(TXT_RECORD);
      }

      /* Other text input mode setup. */
      quote = Q_NOTSET;
      carat = C_NOTSET;
      FL_INIT(is_flags,
          LF_ISSET(TXT_SEARCHINCR) ? IS_RESTART | IS_RUNNING : 0);
      filec_redraw = hexcnt = showmatch = 0;

      /* Initialize input flags. */
      ec_flags = LF_ISSET(TXT_MAPINPUT) ? EC_MAPINPUT : 0;

      /* Refresh the screen. */
      UPDATE_POSITION(sp, tp);
      if (vs_refresh(sp, 1))
            return (1);

      /* If it's dot, just do it now. */
      if (F_ISSET(vp, VC_ISDOT))
            goto replay;

      /* Get an event. */
      evp = &ev;
next: if (v_event_get(sp, evp, 0, ec_flags))
            return (1);

      /*
       * If file completion overwrote part of the screen and nothing else has
       * been displayed, clean up.  We don't do this as part of the normal
       * message resolution because we know the user is on the colon command
       * line and there's no reason to enter explicit characters to continue.
       */
      if (filec_redraw && !F_ISSET(sp, SC_SCR_EXWROTE)) {
            filec_redraw = 0;

            fc.e_event = E_REPAINT;
            fc.e_flno = vip->totalcount >=
                sp->rows ? 1 : sp->rows - vip->totalcount;
            fc.e_tlno = sp->rows;
            vip->linecount = vip->lcontinue = vip->totalcount = 0;
            (void)vs_repaint(sp, &fc);
            (void)vs_refresh(sp, 1);
      }

      /* Deal with all non-character events. */
      switch (evp->e_event) {
      case E_CHARACTER:
            break;
      case E_ERR:
      case E_EOF:
            F_SET(sp, SC_EXIT_FORCE);
            return (1);
      case E_INTERRUPT:
            /*
             * !!!
             * Historically, <interrupt> exited the user from text input
             * mode or cancelled a colon command, and returned to command
             * mode.  It also beeped the terminal, but that seems a bit
             * excessive.
             */
            goto k_escape;
      case E_REPAINT:
            if (vs_repaint(sp, &ev))
                  return (1);
            goto next;
      case E_WRESIZE:
            /* <resize> interrupts the input mode. */
            v_emsg(sp, NULL, VIM_WRESIZE);
            goto k_escape;
      default:
            v_event_err(sp, evp);
            goto k_escape;
      }

      /*
       * !!!
       * If the first character of the input is a nul, replay the previous
       * input.  (Historically, it's okay to replay non-existent input.)
       * This was not documented as far as I know, and is a great test of vi
       * clones.
       */
      if (rcol == 0 && !LF_ISSET(TXT_REPLAY) && evp->e_c == '\0') {
            if (vip->rep == NULL)
                  goto done;

            abb = AB_NOTSET;
            LF_CLR(TXT_RECORD);
            LF_SET(TXT_REPLAY);
            goto replay;
      }

      /*
       * File name completion and colon command-line editing.   We don't
       * have enough meta characters, so we expect people to overload
       * them.  If the two characters are the same, then we do file name
       * completion if the cursor is past the first column, and do colon
       * command-line editing if it's not.
       */
      if (quote == Q_NOTSET) {
            int L__cedit, L__filec;

            L__cedit = L__filec = 0;
            if (LF_ISSET(TXT_CEDIT) && O_STR(sp, O_CEDIT) != NULL &&
                O_STR(sp, O_CEDIT)[0] == evp->e_c)
                  L__cedit = 1;
            if (LF_ISSET(TXT_FILEC) && O_STR(sp, O_FILEC) != NULL &&
                O_STR(sp, O_FILEC)[0] == evp->e_c)
                  L__filec = 1;
            if (L__cedit == 1 && (L__filec == 0 || tp->cno == tp->offset)) {
                  tp->term = TERM_CEDIT;
                  goto k_escape;
            }
            if (L__filec == 1) {
                  if (txt_fc(sp, tp, &filec_redraw))
                        goto err;
                  goto resolve;
            }
      }

      /* Abbreviation overflow check.  See comment in txt_abbrev(). */
#define     MAX_ABBREVIATION_EXPANSION    256
      if (F_ISSET(&evp->e_ch, CH_ABBREVIATED)) {
            if (++abcnt > MAX_ABBREVIATION_EXPANSION) {
                  if (v_event_flush(sp, CH_ABBREVIATED))
                        msgq(sp, M_ERR,
"191|Abbreviation exceeded expansion limit: characters discarded");
                  abcnt = 0;
                  if (LF_ISSET(TXT_REPLAY))
                        goto done;
                  goto resolve;
            }
      } else
            abcnt = 0;

      /* Check to see if the character fits into the replay buffers. */
      if (LF_ISSET(TXT_RECORD)) {
            BINC_GOTO(sp, vip->rep,
                vip->rep_len, (rcol + 1) * sizeof(EVENT));
            vip->rep[rcol++] = *evp;
      }

replay:     if (LF_ISSET(TXT_REPLAY))
            evp = vip->rep + rcol++;

      /* Wrapmargin check for leading space. */
      if (wm_skip) {
            wm_skip = 0;
            if (evp->e_c == ' ')
                  goto resolve;
      }

      /* If quoted by someone else, simply insert the character. */
      if (F_ISSET(&evp->e_ch, CH_QUOTED))
            goto insq_ch;

      /*
       * !!!
       * If this character was quoted by a K_VLNEXT or a backslash, replace
       * the placeholder (a carat or a backslash) with the new character.
       * If it was quoted by a K_VLNEXT, we've already adjusted the cursor
       * because it has to appear on top of the placeholder character.  If
       * it was quoted by a backslash, adjust the cursor now, the cursor
       * doesn't appear on top of it.  Historic practice in both cases.
       *
       * Skip tests for abbreviations; ":ab xa XA" followed by "ixa^V<space>"
       * doesn't perform an abbreviation.  Special case, ^V^J (not ^V^M) is
       * the same as ^J, historically.
       */
      if (quote == Q_BTHIS || quote == Q_VTHIS) {
            FL_CLR(ec_flags, EC_QUOTED);
            if (LF_ISSET(TXT_MAPINPUT))
                  FL_SET(ec_flags, EC_MAPINPUT);

            if (quote == Q_BTHIS &&
                (evp->e_value == K_VERASE || evp->e_value == K_VKILL)) {
                  quote = Q_NOTSET;
                  --tp->cno;
                  ++tp->owrite;
                  goto insl_ch;
            }
            if (quote == Q_VTHIS && evp->e_value != K_NL) {
                  quote = Q_NOTSET;
                  goto insl_ch;
            }
            quote = Q_NOTSET;
      }

      /*
       * !!!
       * Translate "<CH_HEX>[isxdigit()]*" to a character with a hex value:
       * this test delimits the value by any non-hex character.  Offset by
       * one, we use 0 to mean that we've found <CH_HEX>.
       */
      if (hexcnt > 1 && !isxdigit(evp->e_c)) {
            hexcnt = 0;
            if (txt_hex(sp, tp))
                  goto err;
      }

      switch (evp->e_value) {
      case K_CR:                    /* Carriage return. */
      case K_NL:                    /* New line. */
            /* Return in script windows and the command line. */
k_cr:       if (LF_ISSET(TXT_CR)) {
                  /*
                   * If this was a map, we may have not displayed
                   * the line.  Display it, just in case.
                   *
                   * If a script window and not the colon line,
                   * push a <cr> so it gets executed.
                   */
                  if (LF_ISSET(TXT_INFOLINE)) {
                        if (vs_change(sp, tp->lno, LINE_RESET))
                              goto err;
                  } else if (F_ISSET(sp, SC_SCRIPT))
                        (void)v_event_push(sp, NULL, "\r", 1, CH_NOMAP);

                  /* Set term condition: if empty. */
                  if (tp->cno <= tp->offset)
                        tp->term = TERM_CR;
                  /*
                   * Set term condition: if searching incrementally and
                   * the user entered a pattern, return a completed
                   * search, regardless if the entire pattern was found.
                   */
                  if (FL_ISSET(is_flags, IS_RUNNING) &&
                      tp->cno >= tp->offset + 1)
                        tp->term = TERM_SEARCH;

                  goto k_escape;
            }

#define     LINE_RESOLVE {                                        \
            /*                                        \
             * Handle abbreviations.  If there was one, discard the     \
             * replay characters.                           \
             */                                       \
            if (abb == AB_INWORD &&                         \
                !LF_ISSET(TXT_REPLAY) && F_ISSET(gp, G_ABBREV)) { \
                  if (txt_abbrev(sp, tp, &evp->e_c,         \
                      LF_ISSET(TXT_INFOLINE), &tmp,         \
                      &ab_turnoff))                   \
                        goto err;                     \
                  if (tmp) {                          \
                        if (LF_ISSET(TXT_RECORD))           \
                              rcol -= tmp + 1;        \
                        goto resolve;                       \
                  }                                   \
            }                                         \
            if (abb != AB_NOTSET)                           \
                  abb = AB_NOTWORD;                   \
            if (UNMAP_TST)                                  \
                  txt_unmap(sp, tp, &ec_flags);             \
            /*                                        \
             * Delete any appended cursor.  It's possible to get in     \
             * situations where TXT_APPENDEOL is set but tp->insert     \
             * is 0 when using the R command and all the characters     \
             * are tp->owrite characters.                   \
             */                                       \
            if (LF_ISSET(TXT_APPENDEOL) && tp->insert > 0) {      \
                  --tp->len;                          \
                  --tp->insert;                             \
            }                                         \
}
            LINE_RESOLVE;

            /*
             * Save the current line information for restoration in
             * txt_backup(), and set the line final length.
             */
            tp->sv_len = tp->len;
            tp->sv_cno = tp->cno;
            tp->len = tp->cno;

            /* Update the old line. */
            if (vs_change(sp, tp->lno, LINE_RESET))
                  goto err;

            /*
             * Historic practice, when the autoindent edit option was set,
             * was to delete <blank> characters following the inserted
             * newline.  This affected the 'R', 'c', and 's' commands; 'c'
             * and 's' retained the insert characters only, 'R' moved the
             * overwrite and insert characters into the next TEXT structure.
             * We keep track of the number of characters erased for the 'R'
             * command so that the final resolution of the line is correct.
             */
            tp->R_erase = 0;
            owrite = tp->owrite;
            insert = tp->insert;
            if (LF_ISSET(TXT_REPLACE) && owrite != 0) {
                  for (p = tp->lb + tp->cno; owrite > 0 && isblank(*p);
                      ++p, --owrite, ++tp->R_erase);
                  if (owrite == 0)
                        for (; insert > 0 && isblank(*p);
                            ++p, ++tp->R_erase, --insert);
            } else {
                  p = tp->lb + tp->cno + owrite;
                  if (O_ISSET(sp, O_AUTOINDENT))
                        for (; insert > 0 &&
                            isblank(*p); ++p, --insert);
                  owrite = 0;
            }

            /*
             * !!!
             * Create a new line and insert the new TEXT into the queue.
             * DON'T insert until the old line has been updated, or the
             * inserted line count in line.c:db_get() will be wrong.
             */
            if ((ntp = text_init(sp, p,
                insert + owrite, insert + owrite + 32)) == NULL)
                  goto err;
            CIRCLEQ_INSERT_TAIL(&sp->tiq, ntp, q);

            /* Set up bookkeeping for the new line. */
            ntp->insert = insert;
            ntp->owrite = owrite;
            ntp->lno = tp->lno + 1;

            /*
             * Reset the autoindent line value.  0^D keeps the autoindent
             * line from changing, ^D changes the level, even if there were
             * no characters in the old line.  Note, if using the current
             * tp structure, use the cursor as the length, the autoindent
             * characters may have been erased.
             */
            if (LF_ISSET(TXT_AUTOINDENT)) {
                  if (carat == C_NOCHANGE) {
                        if (v_txt_auto(sp, OOBLNO, &ait, ait.ai, ntp))
                              goto err;
                        FREE_SPACE(sp, ait.lb, ait.lb_len);
                  } else
                        if (v_txt_auto(sp, OOBLNO, tp, tp->cno, ntp))
                              goto err;
                  carat = C_NOTSET;
            }

            /* Reset the cursor. */
            ntp->cno = ntp->ai;

            /*
             * If we're here because wrapmargin was set and we've broken a
             * line, there may be additional information (i.e. the start of
             * a line) in the wmt structure.
             */
            if (wm_set) {
                  if (wmt.offset != 0 ||
                      wmt.owrite != 0 || wmt.insert != 0) {
#define     WMTSPACE    wmt.offset + wmt.owrite + wmt.insert
                        BINC_GOTO(sp, ntp->lb,
                            ntp->lb_len, ntp->len + WMTSPACE + 32);
                        memmove(ntp->lb + ntp->cno, wmt.lb, WMTSPACE);
                        ntp->len += WMTSPACE;
                        ntp->cno += wmt.offset;
                        ntp->owrite = wmt.owrite;
                        ntp->insert = wmt.insert;
                  }
                  wm_set = 0;
            }

            /* New lines are TXT_APPENDEOL. */
            if (ntp->owrite == 0 && ntp->insert == 0) {
                  BINC_GOTO(sp, ntp->lb, ntp->lb_len, ntp->len + 1);
                  LF_SET(TXT_APPENDEOL);
                  ntp->lb[ntp->cno] = CH_CURSOR;
                  ++ntp->insert;
                  ++ntp->len;
            }

            /* Swap old and new TEXT's, and update the new line. */
            tp = ntp;
            if (vs_change(sp, tp->lno, LINE_INSERT))
                  goto err;

            goto resolve;
      case K_ESCAPE:                      /* Escape. */
            if (!LF_ISSET(TXT_ESCAPE))
                  goto ins_ch;

            /* If we have a count, start replaying the input. */
            if (rcount > 1) {
                  --rcount;

                  rcol = 0;
                  abb = AB_NOTSET;
                  LF_CLR(TXT_RECORD);
                  LF_SET(TXT_REPLAY);

                  /*
                   * Some commands (e.g. 'o') need a <newline> for each
                   * repetition.
                   */
                  if (LF_ISSET(TXT_ADDNEWLINE))
                        goto k_cr;

                  /*
                   * The R command turns into the 'a' command after the
                   * first repetition.
                   */
                  if (LF_ISSET(TXT_REPLACE)) {
                        tp->insert = tp->owrite;
                        tp->owrite = 0;
                        LF_CLR(TXT_REPLACE);
                  }
                  goto replay;
            }

            /* Set term condition: if empty. */
            if (tp->cno <= tp->offset)
                  tp->term = TERM_ESC;
            /*
             * Set term condition: if searching incrementally and the user
             * entered a pattern, return a completed search, regardless if
             * the entire pattern was found.
             */
            if (FL_ISSET(is_flags, IS_RUNNING) && tp->cno >= tp->offset + 1)
                  tp->term = TERM_SEARCH;

k_escape:   LINE_RESOLVE;

            /*
             * Clean up for the 'R' command, restoring overwrite
             * characters, and making them into insert characters.
             */
            if (LF_ISSET(TXT_REPLACE))
                  txt_Rresolve(sp, &sp->tiq, tp, len);

            /*
             * If there are any overwrite characters, copy down
             * any insert characters, and decrement the length.
             */
            if (tp->owrite) {
                  if (tp->insert)
                        memmove(tp->lb + tp->cno,
                            tp->lb + tp->cno + tp->owrite, tp->insert);
                  tp->len -= tp->owrite;
            }

            /*
             * Optionally resolve the lines into the file.  If not
             * resolving the lines into the file, end the line with
             * a nul.  If the line is empty, then set the length to
             * 0, the termination condition has already been set.
             *
             * XXX
             * This is wrong, should pass back a length.
             */
            if (LF_ISSET(TXT_RESOLVE)) {
                  if (txt_resolve(sp, &sp->tiq, flags))
                        goto err;
            } else {
                  BINC_GOTO(sp, tp->lb, tp->lb_len, tp->len + 1);
                  tp->lb[tp->len] = '\0';
            }

            /*
             * Set the return cursor position to rest on the last
             * inserted character.
             */
            if (tp->cno != 0)
                  --tp->cno;

            /* Update the last line. */
            if (vs_change(sp, tp->lno, LINE_RESET))
                  return (1);
            goto done;
      case K_CARAT:                 /* Delete autoindent chars. */
            if (tp->cno <= tp->ai && LF_ISSET(TXT_AUTOINDENT))
                  carat = C_CARATSET;
            goto ins_ch;
      case K_ZERO:                  /* Delete autoindent chars. */
            if (tp->cno <= tp->ai && LF_ISSET(TXT_AUTOINDENT))
                  carat = C_ZEROSET;
            goto ins_ch;
      case K_CNTRLD:                /* Delete autoindent char. */
            /*
             * If in the first column or no characters to erase, ignore
             * the ^D (this matches historic practice).  If not doing
             * autoindent or already inserted non-ai characters, it's a
             * literal.  The latter test is done in the switch, as the
             * CARAT forms are N + 1, not N.
             */
            if (!LF_ISSET(TXT_AUTOINDENT))
                  goto ins_ch;
            if (tp->cno == 0)
                  goto resolve;

            switch (carat) {
            case C_CARATSET:  /* ^^D */
                  if (tp->ai == 0 || tp->cno > tp->ai + tp->offset + 1)
                        goto ins_ch;

                  /* Save the ai string for later. */
                  ait.lb = NULL;
                  ait.lb_len = 0;
                  BINC_GOTO(sp, ait.lb, ait.lb_len, tp->ai);
                  memmove(ait.lb, tp->lb, tp->ai);
                  ait.ai = ait.len = tp->ai;

                  carat = C_NOCHANGE;
                  goto leftmargin;
            case C_ZEROSET:         /* 0^D */
                  if (tp->ai == 0 || tp->cno > tp->ai + tp->offset + 1)
                        goto ins_ch;

                  carat = C_NOTSET;
leftmargin:       tp->lb[tp->cno - 1] = ' ';
                  tp->owrite += tp->cno - tp->offset;
                  tp->ai = 0;
                  tp->cno = tp->offset;
                  break;
            case C_NOTSET:          /* ^D */
                  if (tp->ai == 0 || tp->cno > tp->ai + tp->offset)
                        goto ins_ch;

                  (void)txt_dent(sp, tp, 0);
                  break;
            default:
                  abort();
            }
            break;
      case K_VERASE:                /* Erase the last character. */
            /* If can erase over the prompt, return. */
            if (tp->cno <= tp->offset && LF_ISSET(TXT_BS)) {
                  tp->term = TERM_BS;
                  goto done;
            }

            /*
             * If at the beginning of the line, try and drop back to a
             * previously inserted line.
             */
            if (tp->cno == 0) {
                  if ((ntp =
                      txt_backup(sp, &sp->tiq, tp, &flags)) == NULL)
                        goto err;
                  tp = ntp;
                  break;
            }

            /* If nothing to erase, bell the user. */
            if (tp->cno <= tp->offset) {
                  if (!LF_ISSET(TXT_REPLAY))
                        txt_nomorech(sp);
                  break;
            }

            /* Drop back one character. */
            --tp->cno;

            /*
             * Historically, vi didn't replace the erased characters with
             * <blank>s, presumably because it's easier to fix a minor
             * typing mistake and continue on if the previous letters are
             * already there.  This is a problem for incremental searching,
             * because the user can no longer tell where they are in the
             * colon command line because the cursor is at the last search
             * point in the screen.  So, if incrementally searching, erase
             * the erased characters from the screen.
             */
            if (FL_ISSET(is_flags, IS_RUNNING))
                  tp->lb[tp->cno] = ' ';

            /*
             * Increment overwrite, decrement ai if deleted.
             *
             * !!!
             * Historic vi did not permit users to use erase characters
             * to delete autoindent characters.  We do.  Eat hot death,
             * POSIX.
             */
            ++tp->owrite;
            if (tp->cno < tp->ai)
                  --tp->ai;

            /* Reset if we deleted an incremental search character. */
            if (FL_ISSET(is_flags, IS_RUNNING))
                  FL_SET(is_flags, IS_RESTART);
            break;
      case K_VWERASE:               /* Skip back one word. */
            /*
             * If at the beginning of the line, try and drop back to a
             * previously inserted line.
             */
            if (tp->cno == 0) {
                  if ((ntp =
                      txt_backup(sp, &sp->tiq, tp, &flags)) == NULL)
                        goto err;
                  tp = ntp;
            }

            /*
             * If at offset, nothing to erase so bell the user.
             */
            if (tp->cno <= tp->offset) {
                  if (!LF_ISSET(TXT_REPLAY))
                        txt_nomorech(sp);
                  break;
            }

            /*
             * The first werase goes back to any autoindent column and the
             * second werase goes back to the offset.
             *
             * !!!
             * Historic vi did not permit users to use erase characters to
             * delete autoindent characters.
             */
            if (tp->ai && tp->cno > tp->ai)
                  max = tp->ai;
            else {
                  tp->ai = 0;
                  max = tp->offset;
            }

            /* Skip over trailing space characters. */
            while (tp->cno > max && isblank(tp->lb[tp->cno - 1])) {
                  --tp->cno;
                  ++tp->owrite;
            }
            if (tp->cno == max)
                  break;
            /*
             * There are three types of word erase found on UNIX systems.
             * They can be identified by how the string /a/b/c is treated
             * -- as 1, 3, or 6 words.  Historic vi had two classes of
             * characters, and strings were delimited by them and
             * <blank>'s, so, 6 words.  The historic tty interface used
             * <blank>'s to delimit strings, so, 1 word.  The algorithm
             * offered in the 4.4BSD tty interface (as stty altwerase)
             * treats it as 3 words -- there are two classes of
             * characters, and strings are delimited by them and
             * <blank>'s.  The difference is that the type of the first
             * erased character erased is ignored, which is exactly right
             * when erasing pathname components.  The edit options
             * TXT_ALTWERASE and TXT_TTYWERASE specify the 4.4BSD tty
             * interface and the historic tty driver behavior,
             * respectively, and the default is the same as the historic
             * vi behavior.
             *
             * Overwrite erased characters if doing incremental search;
             * see comment above.
             */
            if (LF_ISSET(TXT_TTYWERASE))
                  while (tp->cno > max) {
                        --tp->cno;
                        ++tp->owrite;
                        if (FL_ISSET(is_flags, IS_RUNNING))
                              tp->lb[tp->cno] = ' ';
                        if (isblank(tp->lb[tp->cno - 1]))
                              break;
                  }
            else {
                  if (LF_ISSET(TXT_ALTWERASE)) {
                        --tp->cno;
                        ++tp->owrite;
                        if (FL_ISSET(is_flags, IS_RUNNING))
                              tp->lb[tp->cno] = ' ';
                        if (isblank(tp->lb[tp->cno - 1]))
                              break;
                  }
                  if (tp->cno > max)
                        tmp = inword(tp->lb[tp->cno - 1]);
                  while (tp->cno > max) {
                        --tp->cno;
                        ++tp->owrite;
                        if (FL_ISSET(is_flags, IS_RUNNING))
                              tp->lb[tp->cno] = ' ';
                        if (tmp != inword(tp->lb[tp->cno - 1])
                            || isblank(tp->lb[tp->cno - 1]))
                              break;
                  }
            }

            /* Reset if we deleted an incremental search character. */
            if (FL_ISSET(is_flags, IS_RUNNING))
                  FL_SET(is_flags, IS_RESTART);
            break;
      case K_VKILL:                 /* Restart this line. */
            /*
             * !!!
             * If at the beginning of the line, try and drop back to a
             * previously inserted line.  Historic vi did not permit
             * users to go back to previous lines.
             */
            if (tp->cno == 0) {
                  if ((ntp =
                      txt_backup(sp, &sp->tiq, tp, &flags)) == NULL)
                        goto err;
                  tp = ntp;
            }

            /* If at offset, nothing to erase so bell the user. */
            if (tp->cno <= tp->offset) {
                  if (!LF_ISSET(TXT_REPLAY))
                        txt_nomorech(sp);
                  break;
            }

            /*
             * First kill goes back to any autoindent and second kill goes
             * back to the offset.
             *
             * !!!
             * Historic vi did not permit users to use erase characters to
             * delete autoindent characters.
             */
            if (tp->ai && tp->cno > tp->ai)
                  max = tp->ai;
            else {
                  tp->ai = 0;
                  max = tp->offset;
            }
            tp->owrite += tp->cno - max;

            /*
             * Overwrite erased characters if doing incremental search;
             * see comment above.
             */
            if (FL_ISSET(is_flags, IS_RUNNING))
                  do {
                        tp->lb[--tp->cno] = ' ';
                  } while (tp->cno > max);
            else
                  tp->cno = max;

            /* Reset if we deleted an incremental search character. */
            if (FL_ISSET(is_flags, IS_RUNNING))
                  FL_SET(is_flags, IS_RESTART);
            break;
      case K_CNTRLT:                /* Add autoindent characters. */
            if (!LF_ISSET(TXT_CNTRLT))
                  goto ins_ch;
            if (txt_dent(sp, tp, 1))
                  goto err;
            goto ebuf_chk;
      case K_RIGHTBRACE:
      case K_RIGHTPAREN:
            if (LF_ISSET(TXT_SHOWMATCH))
                  showmatch = 1;
            goto ins_ch;
      case K_BACKSLASH:       /* Quote next erase/kill. */
            /*
             * !!!
             * Historic vi tried to make abbreviations after a backslash
             * escape work.  If you did ":ab x y", and inserted "x\^H",
             * (assuming the erase character was ^H) you got "x^H", and
             * no abbreviation was done.  If you inserted "x\z", however,
             * it tried to back up and do the abbreviation, i.e. replace
             * 'x' with 'y'.  The problem was it got it wrong, and you
             * ended up with "zy\".
             *
             * This is really hard to do (you have to remember the
             * word/non-word state, for example), and doesn't make any
             * sense to me.  Both backslash and the characters it
             * (usually) escapes will individually trigger the
             * abbreviation, so I don't see why the combination of them
             * wouldn't.  I don't expect to get caught on this one,
             * particularly since it never worked right, but I've been
             * wrong before.
             *
             * Do the tests for abbreviations, so ":ab xa XA",
             * "ixa<K_VERASE>" performs the abbreviation.
             */
            quote = Q_BNEXT;
            goto insq_ch;
      case K_VLNEXT:                /* Quote next character. */
            evp->e_c = '^';
            quote = Q_VNEXT;
            /*
             * Turn on the quote flag so that the underlying routines
             * quote the next character where it's possible. Turn off
             * the input mapbiting flag so that we don't remap the next
             * character.
             */
            FL_SET(ec_flags, EC_QUOTED);
            FL_CLR(ec_flags, EC_MAPINPUT);

            /*
             * !!!
             * Skip the tests for abbreviations, so ":ab xa XA",
             * "ixa^V<space>" doesn't perform the abbreviation.
             */
            goto insl_ch;
      case K_HEXCHAR:
            hexcnt = 1;
            goto insq_ch;
      default:                /* Insert the character. */
ins_ch:           /*
             * Historically, vi eliminated nul's out of hand.  If the
             * beautify option was set, it also deleted any unknown
             * ASCII value less than space (040) and the del character
             * (0177), except for tabs.  Unknown is a key word here.
             * Most vi documentation claims that it deleted everything
             * but <tab>, <nl> and <ff>, as that's what the original
             * 4BSD documentation said.  This is obviously wrong,
             * however, as <esc> would be included in that list.  What
             * we do is eliminate any unquoted, iscntrl() character that
             * wasn't a replay and wasn't handled specially, except
             * <tab> or <ff>.
             */
            if (LF_ISSET(TXT_BEAUTIFY) && iscntrl(evp->e_c) &&
                evp->e_value != K_FORMFEED && evp->e_value != K_TAB) {
                  msgq(sp, M_BERR,
                      "192|Illegal character; quote to enter");
                  if (LF_ISSET(TXT_REPLAY))
                        goto done;
                  break;
            }

insq_ch:    /*
             * If entering a non-word character after a word, check for
             * abbreviations.  If there was one, discard replay characters.
             * If entering a blank character, check for unmap commands,
             * as well.
             */
            if (!inword(evp->e_c)) {
                  if (abb == AB_INWORD &&
                      !LF_ISSET(TXT_REPLAY) && F_ISSET(gp, G_ABBREV)) {
                        if (txt_abbrev(sp, tp, &evp->e_c,
                            LF_ISSET(TXT_INFOLINE), &tmp, &ab_turnoff))
                              goto err;
                        if (tmp) {
                              if (LF_ISSET(TXT_RECORD))
                                    rcol -= tmp + 1;
                              goto resolve;
                        }
                  }
                  if (isblank(evp->e_c) && UNMAP_TST)
                        txt_unmap(sp, tp, &ec_flags);
            }
            if (abb != AB_NOTSET)
                  abb = inword(evp->e_c) ? AB_INWORD : AB_NOTWORD;

insl_ch:    if (txt_insch(sp, tp, &evp->e_c, flags))
                  goto err;

            /*
             * If we're using K_VLNEXT to quote the next character, then
             * we want the cursor to position itself on the ^ placeholder
             * we're displaying, to match historic practice.
             */
            if (quote == Q_VNEXT) {
                  --tp->cno;
                  ++tp->owrite;
            }

            /*
             * !!!
             * Translate "<CH_HEX>[isxdigit()]*" to a character with
             * a hex value: this test delimits the value by the max
             * number of hex bytes.  Offset by one, we use 0 to mean
             * that we've found <CH_HEX>.
             */
            if (hexcnt != 0 && hexcnt++ == sizeof(CHAR_T) * 2 + 1) {
                  hexcnt = 0;
                  if (txt_hex(sp, tp))
                        goto err;
            }

            /*
             * Check to see if we've crossed the margin.
             *
             * !!!
             * In the historic vi, the wrapmargin value was figured out
             * using the display widths of the characters, i.e. <tab>
             * characters were counted as two characters if the list edit
             * option is set, but as the tabstop edit option number of
             * characters otherwise.  That's what the vs_column() function
             * gives us, so we use it.
             */
            if (margin != 0) {
                  if (vs_column(sp, &tcol))
                        goto err;
                  if (tcol >= margin) {
                        if (txt_margin(sp, tp, &wmt, &tmp, flags))
                              goto err;
                        if (tmp) {
                              if (isblank(evp->e_c))
                                    wm_skip = 1;
                              wm_set = 1;
                              goto k_cr;
                        }
                  }
            }

            /*
             * If we've reached the end of the buffer, then we need to
             * switch into insert mode.  This happens when there's a
             * change to a mark and the user puts in more characters than
             * the length of the motion.
             */
ebuf_chk:   if (tp->cno >= tp->len) {
                  BINC_GOTO(sp, tp->lb, tp->lb_len, tp->len + 1);
                  LF_SET(TXT_APPENDEOL);

                  tp->lb[tp->cno] = CH_CURSOR;
                  ++tp->insert;
                  ++tp->len;
            }

            /* Step the quote state forward. */
            if (quote != Q_NOTSET) {
                  if (quote == Q_BNEXT)
                        quote = Q_BTHIS;
                  if (quote == Q_VNEXT)
                        quote = Q_VTHIS;
            }
            break;
      }

#ifdef DEBUG
      if (tp->cno + tp->insert + tp->owrite != tp->len) {
            msgq(sp, M_ERR,
                "len %u != cno: %u ai: %u insert %u overwrite %u",
                tp->len, tp->cno, tp->ai, tp->insert, tp->owrite);
            if (LF_ISSET(TXT_REPLAY))
                  goto done;
            tp->len = tp->cno + tp->insert + tp->owrite;
      }
#endif

resolve:/*
       * 1: If we don't need to know where the cursor really is and we're
       *    replaying text, keep going.
       */
      if (margin == 0 && LF_ISSET(TXT_REPLAY))
            goto replay;

      /*
       * 2: Reset the line.  Don't bother unless we're about to wait on
       *    a character or we need to know where the cursor really is.
       *    We have to do this before showing matching characters so the
       *    user can see what they're matching.
       */
      if ((margin != 0 || !KEYS_WAITING(sp)) &&
          vs_change(sp, tp->lno, LINE_RESET))
            return (1);

      /*
       * 3: If there aren't keys waiting, display the matching character.
       *    We have to do this before resolving any messages, otherwise
       *    the error message from a missing match won't appear correctly.
       */
      if (showmatch) {
            if (!KEYS_WAITING(sp) && txt_showmatch(sp, tp))
                  return (1);
            showmatch = 0;
      }

      /*
       * 4: If there have been messages and we're not editing on the colon
       *    command line or doing file name completion, resolve them.
       */
      if ((vip->totalcount != 0 || F_ISSET(gp, G_BELLSCHED)) &&
          !F_ISSET(sp, SC_TINPUT_INFO) && !filec_redraw &&
          vs_resolve(sp, NULL, 0))
            return (1);

      /*
       * 5: Refresh the screen if we're about to wait on a character or we
       *    need to know where the cursor really is.
       */
      if (margin != 0 || !KEYS_WAITING(sp)) {
            UPDATE_POSITION(sp, tp);
            if (vs_refresh(sp, margin != 0))
                  return (1);
      }

      /* 6: Proceed with the incremental search. */
      if (FL_ISSET(is_flags, IS_RUNNING) && txt_isrch(sp, vp, tp, &is_flags))
            return (1);

      /* 7: Next character... */
      if (LF_ISSET(TXT_REPLAY))
            goto replay;
      goto next;

done: /* Leave input mode. */
      F_CLR(sp, SC_TINPUT);

      /* If recording for playback, save it. */
      if (LF_ISSET(TXT_RECORD))
            vip->rep_cnt = rcol;

      /*
       * If not working on the colon command line, set the final cursor
       * position.
       */
      if (!F_ISSET(sp, SC_TINPUT_INFO)) {
            vp->m_final.lno = tp->lno;
            vp->m_final.cno = tp->cno;
      }
      return (0);

err:
alloc_err:
      txt_err(sp, &sp->tiq);
      return (1);
}

/*
 * txt_abbrev --
 *    Handle abbreviations.
 */
static int
txt_abbrev(sp, tp, pushcp, isinfoline, didsubp, turnoffp)
      SCR *sp;
      TEXT *tp;
      CHAR_T *pushcp;
      int isinfoline, *didsubp, *turnoffp;
{
      VI_PRIVATE *vip;
      CHAR_T ch, *p;
      SEQ *qp;
      size_t len, off;

      /* Check to make sure we're not at the start of an append. */
      *didsubp = 0;
      if (tp->cno == tp->offset)
            return (0);

      vip = VIP(sp);

      /*
       * Find the start of the "word".
       *
       * !!!
       * We match historic practice, which, as far as I can tell, had an
       * off-by-one error.  The way this worked was that when the inserted
       * text switched from a "word" character to a non-word character,
       * vi would check for possible abbreviations.  It would then take the
       * type (i.e. word/non-word) of the character entered TWO characters
       * ago, and move backward in the text until reaching a character that
       * was not that type, or the beginning of the insert, the line, or
       * the file.  For example, in the string "abc<space>", when the <space>
       * character triggered the abbreviation check, the type of the 'b'
       * character was used for moving through the string.  Maybe there's a
       * reason for not using the first (i.e. 'c') character, but I can't
       * think of one.
       *
       * Terminate at the beginning of the insert or the character after the
       * offset character -- both can be tested for using tp->offset.
       */
      off = tp->cno - 1;                  /* Previous character. */
      p = tp->lb + off;
      len = 1;                      /* One character test. */
      if (off == tp->offset || isblank(p[-1]))
            goto search;
      if (inword(p[-1]))                  /* Move backward to change. */
            for (;;) {
                  --off; --p; ++len;
                  if (off == tp->offset || !inword(p[-1]))
                        break;
            }
      else
            for (;;) {
                  --off; --p; ++len;
                  if (off == tp->offset ||
                      inword(p[-1]) || isblank(p[-1]))
                        break;
            }

      /*
       * !!!
       * Historic vi exploded abbreviations on the command line.  This has
       * obvious problems in that unabbreviating the string can be extremely
       * tricky, particularly if the string has, say, an embedded escape
       * character.  Personally, I think it's a stunningly bad idea.  Other
       * examples of problems this caused in historic vi are:
       *    :ab foo bar
       *    :ab foo baz
       * results in "bar" being abbreviated to "baz", which wasn't what the
       * user had in mind at all.  Also, the commands:
       *    :ab foo bar
       *    :unab foo<space>
       * resulted in an error message that "bar" wasn't mapped.  Finally,
       * since the string was already exploded by the time the unabbreviate
       * command got it, all it knew was that an abbreviation had occurred.
       * Cleverly, it checked the replacement string for its unabbreviation
       * match, which meant that the commands:
       *    :ab foo1 bar
       *    :ab foo2 bar
       *    :unab foo2
       * unabbreviate "foo1", and the commands:
       *    :ab foo bar
       *    :ab bar baz
       * unabbreviate "foo"!
       *
       * Anyway, people neglected to first ask my opinion before they wrote
       * macros that depend on this stuff, so, we make this work as follows.
       * When checking for an abbreviation on the command line, if we get a
       * string which is <blank> terminated and which starts at the beginning
       * of the line, we check to see it is the abbreviate or unabbreviate
       * commands.  If it is, turn abbreviations off and return as if no
       * abbreviation was found.  Note also, minor trickiness, so that if
       * the user erases the line and starts another command, we turn the
       * abbreviations back on.
       *
       * This makes the layering look like a Nachos Supreme.
       */
search:     if (isinfoline)
            if (off == tp->ai || off == tp->offset)
                  if (ex_is_abbrev(p, len)) {
                        *turnoffp = 1;
                        return (0);
                  } else
                        *turnoffp = 0;
            else
                  if (*turnoffp)
                        return (0);

      /* Check for any abbreviations. */
      if ((qp = seq_find(sp, NULL, NULL, p, len, SEQ_ABBREV, NULL)) == NULL)
            return (0);

      /*
       * Push the abbreviation onto the tty stack.  Historically, characters
       * resulting from an abbreviation expansion were themselves subject to
       * map expansions, O_SHOWMATCH matching etc.  This means the expanded
       * characters will be re-tested for abbreviations.  It's difficult to
       * know what historic practice in this case was, since abbreviations
       * were applied to :colon command lines, so entering abbreviations that
       * looped was tricky, although possible.  In addition, obvious loops
       * didn't work as expected.  (The command ':ab a b|ab b c|ab c a' will
       * silently only implement and/or display the last abbreviation.)
       *
       * This implementation doesn't recover well from such abbreviations.
       * The main input loop counts abbreviated characters, and, when it
       * reaches a limit, discards any abbreviated characters on the queue.
       * It's difficult to back up to the original position, as the replay
       * queue would have to be adjusted, and the line state when an initial
       * abbreviated character was received would have to be saved.
       */
      ch = *pushcp;
      if (v_event_push(sp, NULL, &ch, 1, CH_ABBREVIATED))
            return (1);
      if (v_event_push(sp, NULL, qp->output, qp->olen, CH_ABBREVIATED))
            return (1);

      /*
       * If the size of the abbreviation is larger than or equal to the size
       * of the original text, move to the start of the replaced characters,
       * and add their length to the overwrite count.
       *
       * If the abbreviation is smaller than the original text, we have to
       * delete the additional overwrite characters and copy down any insert
       * characters.
       */
      tp->cno -= len;
      if (qp->olen >= len)
            tp->owrite += len;
      else {
            if (tp->insert)
                  memmove(tp->lb + tp->cno + qp->olen,
                      tp->lb + tp->cno + tp->owrite + len, tp->insert);
            tp->owrite += qp->olen;
            tp->len -= len - qp->olen;
      }

      /*
       * We return the length of the abbreviated characters.  This is so
       * the calling routine can replace the replay characters with the
       * abbreviation.  This means that subsequent '.' commands will produce
       * the same text, regardless of intervening :[un]abbreviate commands.
       * This is historic practice.
       */
      *didsubp = len;
      return (0);
}

/*
 * txt_unmap --
 *    Handle the unmap command.
 */
static void
txt_unmap(sp, tp, ec_flagsp)
      SCR *sp;
      TEXT *tp;
      u_int32_t *ec_flagsp;
{
      size_t len, off;
      char *p;

      /* Find the beginning of this "word". */
      for (off = tp->cno - 1, p = tp->lb + off, len = 0;; --p, --off) {
            if (isblank(*p)) {
                  ++p;
                  break;
            }
            ++len;
            if (off == tp->ai || off == tp->offset)
                  break;
      }

      /*
       * !!!
       * Historic vi exploded input mappings on the command line.  See the
       * txt_abbrev() routine for an explanation of the problems inherent
       * in this.
       *
       * We make this work as follows.  If we get a string which is <blank>
       * terminated and which starts at the beginning of the line, we check
       * to see it is the unmap command.  If it is, we return that the input
       * mapping should be turned off.  Note also, minor trickiness, so that
       * if the user erases the line and starts another command, we go ahead
       * an turn mapping back on.
       */
      if ((off == tp->ai || off == tp->offset) && ex_is_unmap(p, len))
            FL_CLR(*ec_flagsp, EC_MAPINPUT);
      else
            FL_SET(*ec_flagsp, EC_MAPINPUT);
}

/*
 * txt_ai_resolve --
 *    When a line is resolved by <esc>, review autoindent characters.
 */
static void
txt_ai_resolve(sp, tp, changedp)
      SCR *sp;
      TEXT *tp;
      int *changedp;
{
      u_long ts;
      int del;
      size_t cno, len, new, old, scno, spaces, tab_after_sp, tabs;
      char *p;

      *changedp = 0;

      /*
       * If the line is empty, has an offset, or no autoindent
       * characters, we're done.
       */
      if (!tp->len || tp->offset || !tp->ai)
            return;

      /*
       * If the length is less than or equal to the autoindent
       * characters, delete them.
       */
      if (tp->len <= tp->ai) {
            tp->ai = tp->cno = tp->len = 0;
            return;
      }

      /*
       * The autoindent characters plus any leading <blank> characters
       * in the line are resolved into the minimum number of characters.
       * Historic practice.
       */
      ts = O_VAL(sp, O_TABSTOP);

      /* Figure out the last <blank> screen column. */
      for (p = tp->lb, scno = 0, len = tp->len,
          spaces = tab_after_sp = 0; len-- && isblank(*p); ++p)
            if (*p == '\t') {
                  if (spaces)
                        tab_after_sp = 1;
                  scno += COL_OFF(scno, ts);
            } else {
                  ++spaces;
                  ++scno;
            }

      /*
       * If there are no spaces, or no tabs after spaces and less than
       * ts spaces, it's already minimal.
       */
      if (!spaces || !tab_after_sp && spaces < ts)
            return;

      /* Count up spaces/tabs needed to get to the target. */
      for (cno = 0, tabs = 0; cno + COL_OFF(cno, ts) <= scno; ++tabs)
            cno += COL_OFF(cno, ts);
      spaces = scno - cno;

      /*
       * Figure out how many characters we're dropping -- if we're not
       * dropping any, it's already minimal, we're done.
       */
      old = p - tp->lb;
      new = spaces + tabs;
      if (old == new)
            return;

      /* Shift the rest of the characters down, adjust the counts. */
      del = old - new;
      memmove(p - del, p, tp->len - old);
      tp->len -= del;
      tp->cno -= del;

      /* Fill in space/tab characters. */
      for (p = tp->lb; tabs--;)
            *p++ = '\t';
      while (spaces--)
            *p++ = ' ';
      *changedp = 1;
}

/*
 * v_txt_auto --
 *    Handle autoindent.  If aitp isn't NULL, use it, otherwise,
 *    retrieve the line.
 *
 * PUBLIC: int v_txt_auto __P((SCR *, recno_t, TEXT *, size_t, TEXT *));
 */
int
v_txt_auto(sp, lno, aitp, len, tp)
      SCR *sp;
      recno_t lno;
      TEXT *aitp, *tp;
      size_t len;
{
      size_t nlen;
      char *p, *t;

      if (aitp == NULL) {
            /*
             * If the ex append command is executed with an address of 0,
             * it's possible to get here with a line number of 0.  Return
             * an indent of 0.
             */
            if (lno == 0) {
                  tp->ai = 0;
                  return (0);
            }
            if (db_get(sp, lno, DBG_FATAL, &t, &len))
                  return (1);
      } else
            t = aitp->lb;

      /* Count whitespace characters. */
      for (p = t; len > 0; ++p, --len)
            if (!isblank(*p))
                  break;

      /* Set count, check for no indentation. */
      if ((nlen = (p - t)) == 0)
            return (0);

      /* Make sure the buffer's big enough. */
      BINC_RET(sp, tp->lb, tp->lb_len, tp->len + nlen);

      /* Copy the buffer's current contents up. */
      if (tp->len != 0)
            memmove(tp->lb + nlen, tp->lb, tp->len);
      tp->len += nlen;

      /* Copy the indentation into the new buffer. */
      memmove(tp->lb, t, nlen);

      /* Set the autoindent count. */
      tp->ai = nlen;
      return (0);
}

/*
 * txt_backup --
 *    Back up to the previously edited line.
 */
static TEXT *
txt_backup(sp, tiqh, tp, flagsp)
      SCR *sp;
      TEXTH *tiqh;
      TEXT *tp;
      u_int32_t *flagsp;
{
      VI_PRIVATE *vip;
      TEXT *ntp;

      /* Get a handle on the previous TEXT structure. */
      if ((ntp = tp->q.cqe_prev) == (void *)tiqh) {
            if (!FL_ISSET(*flagsp, TXT_REPLAY))
                  msgq(sp, M_BERR,
                      "193|Already at the beginning of the insert");
            return (tp);
      }

      /* Bookkeeping. */
      ntp->len = ntp->sv_len;

      /* Handle appending to the line. */
      vip = VIP(sp);
      if (ntp->owrite == 0 && ntp->insert == 0) {
            ntp->lb[ntp->len] = CH_CURSOR;
            ++ntp->insert;
            ++ntp->len;
            FL_SET(*flagsp, TXT_APPENDEOL);
      } else
            FL_CLR(*flagsp, TXT_APPENDEOL);

      /* Release the current TEXT. */
      CIRCLEQ_REMOVE(tiqh, tp, q);
      text_free(tp);

      /* Update the old line on the screen. */
      if (vs_change(sp, ntp->lno + 1, LINE_DELETE))
            return (NULL);

      /* Return the new/current TEXT. */
      return (ntp);
}

/*
 * Text indentation is truly strange.  ^T and ^D do movements to the next or
 * previous shiftwidth value, i.e. for a 1-based numbering, with shiftwidth=3,
 * ^T moves a cursor on the 7th, 8th or 9th column to the 10th column, and ^D
 * moves it back.
 *
 * !!!
 * The ^T and ^D characters in historical vi had special meaning only when they
 * were the first characters entered after entering text input mode.  As normal
 * erase characters couldn't erase autoindent characters (^T in this case), it
 * meant that inserting text into previously existing text was strange -- ^T
 * only worked if it was the first keystroke(s), and then could only be erased
 * using ^D.  This implementation treats ^T specially anywhere it occurs in the
 * input, and permits the standard erase characters to erase the characters it
 * inserts.
 *
 * !!!
 * A fun test is to try:
 *    :se sw=4 ai list
 *    i<CR>^Tx<CR>^Tx<CR>^Tx<CR>^Dx<CR>^Dx<CR>^Dx<esc>
 * Historic vi loses some of the '$' marks on the line ends, but otherwise gets
 * it right.
 *
 * XXX
 * Technically, txt_dent should be part of the screen interface, as it requires
 * knowledge of character sizes, including <space>s, on the screen.  It's here
 * because it's a complicated little beast, and I didn't want to shove it down
 * into the screen.  It's probable that KEY_LEN will call into the screen once
 * there are screens with different character representations.
 *
 * txt_dent --
 *    Handle ^T indents, ^D outdents.
 *
 * If anything changes here, check the ex version to see if it needs similar
 * changes.
 */
static int
txt_dent(sp, tp, isindent)
      SCR *sp;
      TEXT *tp;
      int isindent;
{
      CHAR_T ch;
      u_long sw, ts;
      size_t cno, current, spaces, target, tabs, off;
      int ai_reset;

      ts = O_VAL(sp, O_TABSTOP);
      sw = O_VAL(sp, O_SHIFTWIDTH);

      /*
       * Since we don't know what precedes the character(s) being inserted
       * (or deleted), the preceding whitespace characters must be resolved.
       * An example is a <tab>, which doesn't need a full shiftwidth number
       * of columns because it's preceded by <space>s.  This is easy to get
       * if the user sets shiftwidth to a value less than tabstop (or worse,
       * something for which tabstop isn't a multiple) and then uses ^T to
       * indent, and ^D to outdent.
       *
       * Figure out the current and target screen columns.  In the historic
       * vi, the autoindent column was NOT determined using display widths
       * of characters as was the wrapmargin column.  For that reason, we
       * can't use the vs_column() function, but have to calculate it here.
       * This is slow, but it's normally only on the first few characters of
       * a line.
       */
      for (current = cno = 0; cno < tp->cno; ++cno)
            current += tp->lb[cno] == '\t' ?
                COL_OFF(current, ts) : KEY_LEN(sp, tp->lb[cno]);

      target = current;
      if (isindent)
            target += COL_OFF(target, sw);
      else
            target -= --target % sw;

      /*
       * The AI characters will be turned into overwrite characters if the
       * cursor immediately follows them.  We test both the cursor position
       * and the indent flag because there's no single test.  (^T can only
       * be detected by the cursor position, and while we know that the test
       * is always true for ^D, the cursor can be in more than one place, as
       * "0^D" and "^D" are different.)
       */
      ai_reset = !isindent || tp->cno == tp->ai + tp->offset;

      /*
       * Back up over any previous <blank> characters, changing them into
       * overwrite characters (including any ai characters).  Then figure
       * out the current screen column.
       */
      for (; tp->cno > tp->offset &&
          (tp->lb[tp->cno - 1] == ' ' || tp->lb[tp->cno - 1] == '\t');
          --tp->cno, ++tp->owrite);
      for (current = cno = 0; cno < tp->cno; ++cno)
            current += tp->lb[cno] == '\t' ?
                COL_OFF(current, ts) : KEY_LEN(sp, tp->lb[cno]);

      /*
       * If we didn't move up to or past the target, it's because there
       * weren't enough characters to delete, e.g. the first character
       * of the line was a tp->offset character, and the user entered
       * ^D to move to the beginning of a line.  An example of this is:
       *
       *    :set ai sw=4<cr>i<space>a<esc>i^T^D
       *
       * Otherwise, count up the total spaces/tabs needed to get from the
       * beginning of the line (or the last non-<blank> character) to the
       * target.
       */
      if (current >= target)
            spaces = tabs = 0;
      else {
            for (cno = current,
                tabs = 0; cno + COL_OFF(cno, ts) <= target; ++tabs)
                  cno += COL_OFF(cno, ts);
            spaces = target - cno;
      }

      /* If we overwrote ai characters, reset the ai count. */
      if (ai_reset)
            tp->ai = tabs + spaces;

      /*
       * Call txt_insch() to insert each character, so that we get the
       * correct effect when we add a <tab> to replace N <spaces>.
       */
      for (ch = '\t'; tabs > 0; --tabs)
            (void)txt_insch(sp, tp, &ch, 0);
      for (ch = ' '; spaces > 0; --spaces)
            (void)txt_insch(sp, tp, &ch, 0);
      return (0);
}

/*
 * txt_fc --
 *    File name completion.
 */
static int
txt_fc(sp, tp, redrawp)
      SCR *sp;
      TEXT *tp;
      int *redrawp;
{
      struct stat sb;
      ARGS **argv;
      CHAR_T s_ch;
      EXCMD cmd;
      size_t indx, len, nlen, off;
      int argc, trydir;
      char *p, *t;

      trydir = 0;
      *redrawp = 0;

      /*
       * Find the beginning of this "word" -- if we're at the beginning
       * of the line, it's a special case.
       */
      if (tp->cno == 1) {
            len = 0;
            p = tp->lb;
      } else
retry:            for (len = 0,
                off = tp->cno - 1, p = tp->lb + off;; --off, --p) {
                  if (isblank(*p)) {
                        ++p;
                        break;
                  }
                  ++len;
                  if (off == tp->ai || off == tp->offset)
                        break;
            }

      /*
       * Get enough space for a wildcard character.
       *
       * XXX
       * This won't work for "foo\", since the \ will escape the expansion
       * character.  I'm not sure if that's a bug or not...
       */
      off = p - tp->lb;
      BINC_RET(sp, tp->lb, tp->lb_len, tp->len + 1);
      p = tp->lb + off;

      s_ch = p[len];
      p[len] = '*';

      /* Build an ex command, and call the ex expansion routines. */
      ex_cinit(&cmd, 0, 0, OOBLNO, OOBLNO, 0, NULL);
      if (argv_init(sp, &cmd))
            return (1);
      if (argv_exp2(sp, &cmd, p, len + 1)) {
            p[len] = s_ch;
            return (0);
      }
      argc = cmd.argc;
      argv = cmd.argv;

      p[len] = s_ch;

      switch (argc) {
      case 0:                       /* No matches. */
            if (!trydir)
                  (void)sp->gp->scr_bell(sp);
            return (0);
      case 1:                       /* One match. */
            /* If something changed, do the exchange. */
            nlen = strlen(cmd.argv[0]->bp);
            if (len != nlen || memcmp(cmd.argv[0]->bp, p, len))
                  break;

            /* If haven't done a directory test, do it now. */
            if (!trydir &&
                !stat(cmd.argv[0]->bp, &sb) && S_ISDIR(sb.st_mode)) {
                  p += len;
                  goto isdir;
            }

            /* If nothing changed, period, ring the bell. */
            if (!trydir)
                  (void)sp->gp->scr_bell(sp);
            return (0);
      default:                /* Multiple matches. */
            *redrawp = 1;
            if (txt_fc_col(sp, argc, argv))
                  return (1);

            /* Find the length of the shortest match. */
            for (nlen = cmd.argv[0]->len; --argc > 0;) {
                  if (cmd.argv[argc]->len < nlen)
                        nlen = cmd.argv[argc]->len;
                  for (indx = 0; indx < nlen &&
                      cmd.argv[argc]->bp[indx] == cmd.argv[0]->bp[indx];
                      ++indx);
                  nlen = indx;
            }
            break;
      }

      /* Overwrite the expanded text first. */
      for (t = cmd.argv[0]->bp; len > 0 && nlen > 0; --len, --nlen)
            *p++ = *t++;

      /* If lost text, make the remaining old text overwrite characters. */
      if (len) {
            tp->cno -= len;
            tp->owrite += len;
      }

      /* Overwrite any overwrite characters next. */
      for (; nlen > 0 && tp->owrite > 0; --nlen, --tp->owrite, ++tp->cno)
            *p++ = *t++;

      /* Shift remaining text up, and move the cursor to the end. */
      if (nlen) {
            off = p - tp->lb;
            BINC_RET(sp, tp->lb, tp->lb_len, tp->len + nlen);
            p = tp->lb + off;

            tp->cno += nlen;
            tp->len += nlen;

            if (tp->insert != 0)
                  (void)memmove(p + nlen, p, tp->insert);
            while (nlen--)
                  *p++ = *t++;
      }

      /* If a single match and it's a directory, retry it. */
      if (argc == 1 && !stat(cmd.argv[0]->bp, &sb) && S_ISDIR(sb.st_mode)) {
isdir:            if (tp->owrite == 0) {
                  off = p - tp->lb;
                  BINC_RET(sp, tp->lb, tp->lb_len, tp->len + 1);
                  p = tp->lb + off;
                  if (tp->insert != 0)
                        (void)memmove(p + 1, p, tp->insert);
                  ++tp->len;
            } else
                  --tp->owrite;

            ++tp->cno;
            *p++ = '/';

            trydir = 1;
            goto retry;
      }
      return (0);
}

/*
 * txt_fc_col --
 *    Display file names for file name completion.
 */
static int
txt_fc_col(sp, argc, argv)
      SCR *sp;
      int argc;
      ARGS **argv;
{
      ARGS **av;
      CHAR_T *p;
      GS *gp;
      size_t base, cnt, col, colwidth, numrows, numcols, prefix, row;
      int ac, nf, reset;

      gp = sp->gp;

      /* Trim any directory prefix common to all of the files. */
      if ((p = strrchr(argv[0]->bp, '/')) == NULL)
            prefix = 0;
      else {
            prefix = (p - argv[0]->bp) + 1;
            for (ac = argc - 1, av = argv + 1; ac > 0; --ac, ++av)
                  if (av[0]->len < prefix ||
                      memcmp(av[0]->bp, argv[0]->bp, prefix)) {
                        prefix = 0;
                        break;
                  }
      }

      /*
       * Figure out the column width for the longest name.  Output is done on
       * 6 character "tab" boundaries for no particular reason.  (Since we
       * don't output tab characters, we ignore the terminal's tab settings.)
       * Ignore the user's tab setting because we have no idea how reasonable
       * it is.
       */
      for (ac = argc, av = argv, colwidth = 0; ac > 0; --ac, ++av) {
            for (col = 0, p = av[0]->bp + prefix; *p != '\0'; ++p)
                  col += KEY_LEN(sp, *p);
            if (col > colwidth)
                  colwidth = col;
      }
      colwidth += COL_OFF(colwidth, 6);

      /*
       * Writing to the bottom line of the screen is always turned off when
       * SC_TINPUT_INFO is set.  Turn it back on, we know what we're doing.
       */
      if (F_ISSET(sp, SC_TINPUT_INFO)) {
            reset = 1;
            F_CLR(sp, SC_TINPUT_INFO);
      } else
            reset = 0;

#define     CHK_INTR                                        \
      if (F_ISSET(gp, G_INTERRUPTED))                             \
            goto intr;

      /* If the largest file name is too large, just print them. */
      if (colwidth > sp->cols) {
            p = msg_print(sp, av[0]->bp + prefix, &nf);
            for (ac = argc, av = argv; ac > 0; --ac, ++av) {
                  (void)ex_printf(sp, "%s\n", p);
                  if (F_ISSET(gp, G_INTERRUPTED))
                        break;
            }
            if (nf)
                  FREE_SPACE(sp, p, 0);
            CHK_INTR;
      } else {
            /* Figure out the number of columns. */
            numcols = (sp->cols - 1) / colwidth;
            if (argc > numcols) {
                  numrows = argc / numcols;
                  if (argc % numcols)
                        ++numrows;
            } else
                  numrows = 1;

            /* Display the files in sorted order. */
            for (row = 0; row < numrows; ++row) {
                  for (base = row, col = 0; col < numcols; ++col) {
                        p = msg_print(sp, argv[base]->bp + prefix, &nf);
                        cnt = ex_printf(sp, "%s", p);
                        if (nf)
                              FREE_SPACE(sp, p, 0);
                        CHK_INTR;
                        if ((base += numrows) >= argc)
                              break;
                        (void)ex_printf(sp,
                            "%*s", (int)(colwidth - cnt), "");
                        CHK_INTR;
                  }
                  (void)ex_puts(sp, "\n");
                  CHK_INTR;
            }
            (void)ex_puts(sp, "\n");
            CHK_INTR;
      }
      (void)ex_fflush(sp);

      if (0) {
intr:       F_CLR(gp, G_INTERRUPTED);
      }
      if (reset)
            F_SET(sp, SC_TINPUT_INFO);

      return (0);
}

/*
 * txt_emark --
 *    Set the end mark on the line.
 */
static int
txt_emark(sp, tp, cno)
      SCR *sp;
      TEXT *tp;
      size_t cno;
{
      CHAR_T ch, *kp;
      size_t chlen, nlen, olen;
      char *p;

      ch = CH_ENDMARK;

      /*
       * The end mark may not be the same size as the current character.
       * Don't let the line shift.
       */
      nlen = KEY_LEN(sp, ch);
      if (tp->lb[cno] == '\t')
            (void)vs_columns(sp, tp->lb, tp->lno, &cno, &olen);
      else
            olen = KEY_LEN(sp, tp->lb[cno]);

      /*
       * If the line got longer, well, it's weird, but it's easy.  If
       * it's the same length, it's easy.  If it got shorter, we have
       * to fix it up.
       */
      if (olen > nlen) {
            BINC_RET(sp, tp->lb, tp->lb_len, tp->len + olen);
            chlen = olen - nlen;
            if (tp->insert != 0)
                  memmove(tp->lb + cno + 1 + chlen,
                      tp->lb + cno + 1, tp->insert);

            tp->len += chlen;
            tp->owrite += chlen;
            p = tp->lb + cno;
            if (tp->lb[cno] == '\t')
                  for (cno += chlen; chlen--;)
                        *p++ = ' ';
            else
                  for (kp = KEY_NAME(sp, tp->lb[cno]),
                      cno += chlen; chlen--;)
                        *p++ = *kp++;
      }
      tp->lb[cno] = ch;
      return (vs_change(sp, tp->lno, LINE_RESET));
}

/*
 * txt_err --
 *    Handle an error during input processing.
 */
static void
txt_err(sp, tiqh)
      SCR *sp;
      TEXTH *tiqh;
{
      recno_t lno;

      /*
       * The problem with input processing is that the cursor is at an
       * indeterminate position since some input may have been lost due
       * to a malloc error.  So, try to go back to the place from which
       * the cursor started, knowing that it may no longer be available.
       *
       * We depend on at least one line number being set in the text
       * chain.
       */
      for (lno = tiqh->cqh_first->lno;
          !db_exist(sp, lno) && lno > 0; --lno);

      sp->lno = lno == 0 ? 1 : lno;
      sp->cno = 0;

      /* Redraw the screen, just in case. */
      F_SET(sp, SC_SCR_REDRAW);
}

/*
 * txt_hex --
 *    Let the user insert any character value they want.
 *
 * !!!
 * This is an extension.  The pattern "^X[0-9a-fA-F]*" is a way
 * for the user to specify a character value which their keyboard
 * may not be able to enter.
 */
static int
txt_hex(sp, tp)
      SCR *sp;
      TEXT *tp;
{
      CHAR_T savec;
      size_t len, off;
      u_long value;
      char *p, *wp;

      /*
       * Null-terminate the string.  Since nul isn't a legal hex value,
       * this should be okay, and lets us use a local routine, which
       * presumably understands the character set, to convert the value.
       */
      savec = tp->lb[tp->cno];
      tp->lb[tp->cno] = 0;

      /* Find the previous CH_HEX character. */
      for (off = tp->cno - 1, p = tp->lb + off, len = 0;; --p, --off, ++len) {
            if (*p == CH_HEX) {
                  wp = p + 1;
                  break;
            }
            /* Not on this line?  Shouldn't happen. */
            if (off == tp->ai || off == tp->offset)
                  goto nothex;
      }

      /* If length of 0, then it wasn't a hex value. */
      if (len == 0)
            goto nothex;

      /* Get the value. */
      errno = 0;
      value = strtol(wp, NULL, 16);
      if (errno || value > MAX_CHAR_T) {
nothex:           tp->lb[tp->cno] = savec;
            return (0);
      }

      /* Restore the original character. */
      tp->lb[tp->cno] = savec;

      /* Adjust the bookkeeping. */
      tp->cno -= len;
      tp->len -= len;
      tp->lb[tp->cno - 1] = value;

      /* Copy down any overwrite characters. */
      if (tp->owrite)
            memmove(tp->lb + tp->cno, tp->lb + tp->cno + len, tp->owrite);

      /* Copy down any insert characters. */
      if (tp->insert)
            memmove(tp->lb + tp->cno + tp->owrite,
                tp->lb + tp->cno + tp->owrite + len, tp->insert);

      return (0);
}

/*
 * txt_insch --
 *
 * !!!
 * Historic vi did a special screen optimization for tab characters.  As an
 * example, for the keystrokes "iabcd<esc>0C<tab>", the tab overwrote the
 * rest of the string when it was displayed.
 *
 * Because early versions of this implementation redisplayed the entire line
 * on each keystroke, the "bcd" was pushed to the right as it ignored that
 * the user had "promised" to change the rest of the characters.  However,
 * the historic vi implementation had an even worse bug: given the keystrokes
 * "iabcd<esc>0R<tab><esc>", the "bcd" disappears, and magically reappears
 * on the second <esc> key.
 *
 * POSIX 1003.2 requires (will require) that this be fixed, specifying that
 * vi overwrite characters the user has committed to changing, on the basis
 * of the screen space they require, but that it not overwrite other characters.
 */
static int
txt_insch(sp, tp, chp, flags)
      SCR *sp;
      TEXT *tp;
      CHAR_T *chp;
      u_int flags;
{
      CHAR_T *kp, savech;
      size_t chlen, cno, copydown, olen, nlen;
      char *p;

      /*
       * This probably isn't the best place for the Vigor handling.
       * More particularly, we should ideally ensure that the screen
       * is up-to-date at this point.  However, I have completely ignored
       * screen updates in Vigor so far, so I suppose I can carry on
       * this perfectly fine tradition.
       */
      vigor_gotchar(*chp);

      /*
       * The 'R' command does one-for-one replacement, because there's
       * no way to know how many characters the user intends to replace.
       */
      if (LF_ISSET(TXT_REPLACE)) {
            if (tp->owrite) {
                  --tp->owrite;
                  tp->lb[tp->cno++] = *chp;
                  return (0);
            }
      } else if (tp->owrite) {            /* Overwrite a character. */
            cno = tp->cno;

            /*
             * If the old or new characters are tabs, then the length of the
             * display depends on the character position in the display.  We
             * don't even try to handle this here, just ask the screen.
             */
            if (*chp == '\t') {
                  savech = tp->lb[cno];
                  tp->lb[cno] = '\t';
                  (void)vs_columns(sp, tp->lb, tp->lno, &cno, &nlen);
                  tp->lb[cno] = savech;
            } else
                  nlen = KEY_LEN(sp, *chp);

            /*
             * Eat overwrite characters until we run out of them or we've
             * handled the length of the new character.  If we only eat
             * part of an overwrite character, break it into its component
             * elements and display the remaining components.
             */
            for (copydown = 0; nlen != 0 && tp->owrite != 0;) {
                  --tp->owrite;

                  if (tp->lb[cno] == '\t')
                        (void)vs_columns(sp,
                            tp->lb, tp->lno, &cno, &olen);
                  else
                        olen = KEY_LEN(sp, tp->lb[cno]);

                  if (olen == nlen) {
                        nlen = 0;
                        break;
                  }
                  if (olen < nlen) {
                        ++copydown;
                        nlen -= olen;
                  } else {
                        BINC_RET(sp,
                            tp->lb, tp->lb_len, tp->len + olen);
                        chlen = olen - nlen;
                        memmove(tp->lb + cno + 1 + chlen,
                            tp->lb + cno + 1, tp->owrite + tp->insert);

                        tp->len += chlen;
                        tp->owrite += chlen;
                        if (tp->lb[cno] == '\t')
                              for (p = tp->lb + cno + 1; chlen--;)
                                    *p++ = ' ';
                        else
                              for (kp =
                                  KEY_NAME(sp, tp->lb[cno]) + nlen,
                                  p = tp->lb + cno + 1; chlen--;)
                                    *p++ = *kp++;
                        nlen = 0;
                        break;
                  }
            }

            /*
             * If had to erase several characters, we adjust the total
             * count, and if there are any characters left, shift them
             * into position.
             */
            if (copydown != 0 && (tp->len -= copydown) != 0)
                  memmove(tp->lb + cno, tp->lb + cno + copydown,
                      tp->owrite + tp->insert + copydown);

            /* If we had enough overwrite characters, we're done. */
            if (nlen == 0) {
                  tp->lb[tp->cno++] = *chp;
                  return (0);
            }
      }

      /* Check to see if the character fits into the input buffer. */
      BINC_RET(sp, tp->lb, tp->lb_len, tp->len + 1);

      ++tp->len;
      if (tp->insert) {             /* Insert a character. */
            if (tp->insert == 1)
                  tp->lb[tp->cno + 1] = tp->lb[tp->cno];
            else
                  memmove(tp->lb + tp->cno + 1,
                      tp->lb + tp->cno, tp->owrite + tp->insert);
      }
      tp->lb[tp->cno++] = *chp;
      return (0);
}

/*
 * txt_isrch --
 *    Do an incremental search.
 */
static int
txt_isrch(sp, vp, tp, is_flagsp)
      SCR *sp;
      VICMD *vp;
      TEXT *tp;
      u_int8_t *is_flagsp;
{
      MARK start;
      recno_t lno;
      u_int sf;

      /* If it's a one-line screen, we don't do incrementals. */
      if (IS_ONELINE(sp)) {
            FL_CLR(*is_flagsp, IS_RUNNING);
            return (0);
      }

      /*
       * If the user erases back to the beginning of the buffer, there's
       * nothing to search for.  Reset the cursor to the starting point.
       */
      if (tp->cno <= 1) {
            vp->m_final = vp->m_start;
            return (0);
      }

      /*
       * If it's an RE quote character, and not quoted, ignore it until
       * we get another character.
       */
      if (tp->lb[tp->cno - 1] == '\\' &&
          (tp->cno == 2 || tp->lb[tp->cno - 2] != '\\'))
            return (0);

      /*
       * If it's a magic shell character, and not quoted, reset the cursor
       * to the starting point.
       */
      if (strchr(O_STR(sp, O_SHELLMETA), tp->lb[tp->cno - 1]) != NULL &&
          (tp->cno == 2 || tp->lb[tp->cno - 2] != '\\'))
            vp->m_final = vp->m_start;

      /*
       * If we see the search pattern termination character, then quit doing
       * an incremental search.  There may be more, e.g., ":/foo/;/bar/",
       * and we can't handle that incrementally.  Also, reset the cursor to
       * the original location, the ex search routines don't know anything
       * about incremental searches.
       */
      if (tp->lb[0] == tp->lb[tp->cno - 1] &&
          (tp->cno == 2 || tp->lb[tp->cno - 2] != '\\')) {
            vp->m_final = vp->m_start;
            FL_CLR(*is_flagsp, IS_RUNNING);
            return (0);
      }
            
      /*
       * Remember the input line and discard the special input map,
       * but don't overwrite the input line on the screen.
       */
      lno = tp->lno;
      F_SET(VIP(sp), VIP_S_MODELINE);
      F_CLR(sp, SC_TINPUT | SC_TINPUT_INFO);
      if (txt_map_end(sp))
            return (1);

      /*
       * Specify a starting point and search.  If we find a match, move to
       * it and refresh the screen.  If we didn't find the match, then we
       * beep the screen.  When searching from the original cursor position, 
       * we have to move the cursor, otherwise, we don't want to move the
       * cursor in case the text at the current position continues to match.
       */
      if (FL_ISSET(*is_flagsp, IS_RESTART)) {
            start = vp->m_start;
            sf = SEARCH_SET;
      } else {
            start = vp->m_final;
            sf = SEARCH_INCR | SEARCH_SET;
      }

      if (tp->lb[0] == '/' ?
          !f_search(sp,
          &start, &vp->m_final, tp->lb + 1, tp->cno - 1, NULL, sf) :
          !b_search(sp,
          &start, &vp->m_final, tp->lb + 1, tp->cno - 1, NULL, sf)) {
            sp->lno = vp->m_final.lno;
            sp->cno = vp->m_final.cno;
            FL_CLR(*is_flagsp, IS_RESTART);

            if (!KEYS_WAITING(sp) && vs_refresh(sp, 0))
                  return (1);
      } else
            FL_SET(*is_flagsp, IS_RESTART);

      /* Reinstantiate the special input map. */
      if (txt_map_init(sp))
            return (1);
      F_CLR(VIP(sp), VIP_S_MODELINE);
      F_SET(sp, SC_TINPUT | SC_TINPUT_INFO);

      /* Reset the line number of the input line. */
      tp->lno = TMAP[0].lno; 

      /*
       * If the colon command-line moved, i.e. the screen scrolled,
       * refresh the input line.
       *
       * XXX
       * We shouldn't be calling vs_line, here -- we need dirty bits
       * on entries in the SMAP array.
       */
      if (lno != TMAP[0].lno) {
            if (vs_line(sp, &TMAP[0], NULL, NULL))
                  return (1);
            (void)sp->gp->scr_refresh(sp, 0);
      }
      return (0);
}

/*
 * txt_resolve --
 *    Resolve the input text chain into the file.
 */
static int
txt_resolve(sp, tiqh, flags)
      SCR *sp;
      TEXTH *tiqh;
      u_int32_t flags;
{
      VI_PRIVATE *vip;
      TEXT *tp;
      recno_t lno;
      int changed;

      /*
       * The first line replaces a current line, and all subsequent lines
       * are appended into the file.  Resolve autoindented characters for
       * each line before committing it.  If the latter causes the line to
       * change, we have to redisplay it, otherwise the information cached
       * about the line will be wrong.
       */
      vip = VIP(sp);
      tp = tiqh->cqh_first;

      if (LF_ISSET(TXT_AUTOINDENT))
            txt_ai_resolve(sp, tp, &changed);
      else
            changed = 0;
      if (db_set(sp, tp->lno, tp->lb, tp->len) ||
          changed && vs_change(sp, tp->lno, LINE_RESET))
            return (1);

      for (lno = tp->lno; (tp = tp->q.cqe_next) != (void *)&sp->tiq; ++lno) {
            if (LF_ISSET(TXT_AUTOINDENT))
                  txt_ai_resolve(sp, tp, &changed);
            else
                  changed = 0;
            if (db_append(sp, 0, lno, tp->lb, tp->len) ||
                changed && vs_change(sp, tp->lno, LINE_RESET))
                  return (1);
      }

      /*
       * Clear the input flag, the look-aside buffer is no longer valid.
       * Has to be done as part of text resolution, or upon return we'll
       * be looking at incorrect data.
       */
      F_CLR(sp, SC_TINPUT);

      return (0);
}

/*
 * txt_showmatch --
 *    Show a character match.
 *
 * !!!
 * Historic vi tried to display matches even in the :colon command line.
 * I think not.
 */
static int
txt_showmatch(sp, tp)
      SCR *sp;
      TEXT *tp;
{
      GS *gp;
      VCS cs;
      MARK m;
      int cnt, endc, startc;

      gp = sp->gp;

      /*
       * Do a refresh first, in case we haven't done one in awhile,
       * so the user can see what we're complaining about.
       */
      UPDATE_POSITION(sp, tp);
      if (vs_refresh(sp, 1))
            return (1);

      /*
       * We don't display the match if it's not on the screen.  Find
       * out what the first character on the screen is.
       */
      if (vs_sm_position(sp, &m, 0, P_TOP))
            return (1);

      /* Initialize the getc() interface. */
      cs.cs_lno = tp->lno;
      cs.cs_cno = tp->cno - 1;
      if (cs_init(sp, &cs))
            return (1);
      startc = (endc = cs.cs_ch)  == ')' ? '(' : '{';

      /* Search for the match. */
      for (cnt = 1;;) {
            if (cs_prev(sp, &cs))
                  return (1);
            if (cs.cs_flags != 0) {
                  if (cs.cs_flags == CS_EOF || cs.cs_flags == CS_SOF) {
                        msgq(sp, M_BERR,
                            "Unmatched %s", KEY_NAME(sp, endc));
                        return (0);
                  }
                  continue;
            }
            if (cs.cs_ch == endc)
                  ++cnt;
            else if (cs.cs_ch == startc && --cnt == 0)
                  break;
      }

      /* If the match is on the screen, move to it. */
      if (cs.cs_lno < m.lno || cs.cs_lno == m.lno && cs.cs_cno < m.cno)
            return (0);
      sp->lno = cs.cs_lno;
      sp->cno = cs.cs_cno;
      if (vs_refresh(sp, 1))
            return (1);

      /* Wait for timeout or character arrival. */
      return (v_event_get(sp,
          NULL, O_VAL(sp, O_MATCHTIME) * 100, EC_TIMEOUT));
}

/*
 * txt_margin --
 *    Handle margin wrap.
 */
static int
txt_margin(sp, tp, wmtp, didbreak, flags)
      SCR *sp;
      TEXT *tp, *wmtp;
      int *didbreak;
      u_int32_t flags;
{
      VI_PRIVATE *vip;
      size_t len, off;
      char *p, *wp;

      /* Find the nearest previous blank. */
      for (off = tp->cno - 1, p = tp->lb + off, len = 0;; --off, --p, ++len) {
            if (isblank(*p)) {
                  wp = p + 1;
                  break;
            }

            /*
             * If reach the start of the line, there's nowhere to break.
             *
             * !!!
             * Historic vi belled each time a character was entered after
             * crossing the margin until a space was entered which could
             * be used to break the line.  I don't as it tends to wake the
             * cats.
             */
            if (off == tp->ai || off == tp->offset) {
                  *didbreak = 0;
                  return (0);
            }
      }

      /*
       * Store saved information about the rest of the line in the
       * wrapmargin TEXT structure.
       *
       * !!!
       * The offset field holds the length of the current characters
       * that the user entered, but which are getting split to the new
       * line -- it's going to be used to set the cursor value when we
       * move to the new line.
       */
      vip = VIP(sp);
      wmtp->lb = p + 1;
      wmtp->offset = len;
      wmtp->insert = LF_ISSET(TXT_APPENDEOL) ?  tp->insert - 1 : tp->insert;
      wmtp->owrite = tp->owrite;

      /* Correct current bookkeeping information. */
      tp->cno -= len;
      if (LF_ISSET(TXT_APPENDEOL)) {
            tp->len -= len + tp->owrite + (tp->insert - 1);
            tp->insert = 1;
      } else {
            tp->len -= len + tp->owrite + tp->insert;
            tp->insert = 0;
      }
      tp->owrite = 0;

      /*
       * !!!
       * Delete any trailing whitespace from the current line.
       */
      for (;; --p, --off) {
            if (!isblank(*p))
                  break;
            --tp->cno;
            --tp->len;
            if (off == tp->ai || off == tp->offset)
                  break;
      }
      *didbreak = 1;
      return (0);
}

/*
 * txt_Rresolve --
 *    Resolve the input line for the 'R' command.
 */
static void
txt_Rresolve(sp, tiqh, tp, orig_len)
      SCR *sp;
      TEXTH *tiqh;
      TEXT *tp;
      const size_t orig_len;
{
      TEXT *ttp;
      size_t input_len, retain;
      char *p;

      /*
       * Check to make sure that the cursor hasn't moved beyond
       * the end of the line.
       */
      if (tp->owrite == 0)
            return;

      /*
       * Calculate how many characters the user has entered,
       * plus the blanks erased by <carriage-return>/<newline>s.
       */
      for (ttp = tiqh->cqh_first, input_len = 0;;) {
            input_len += ttp == tp ? tp->cno : ttp->len + ttp->R_erase;
            if ((ttp = ttp->q.cqe_next) == (void *)&sp->tiq)
                  break;
      }

      /*
       * If the user has entered less characters than the original line
       * was long, restore any overwriteable characters to the original
       * characters.  These characters are entered as "insert characters",
       * because they're after the cursor and we don't want to lose them.
       * (This is okay because the R command has no insert characters.)
       * We set owrite to 0 so that the insert characters don't get copied
       * to somewhere else, which means that the line and the length have
       * to be adjusted here as well.
       *
       * We have to retrieve the original line because the original pinned
       * page has long since been discarded.  If it doesn't exist, that's
       * okay, the user just extended the file.
       */
      if (input_len < orig_len) {
            retain = MIN(tp->owrite, orig_len - input_len);
            if (db_get(sp,
                tiqh->cqh_first->lno, DBG_FATAL | DBG_NOCACHE, &p, NULL))
                  return;
            memcpy(tp->lb + tp->cno, p + input_len, retain);
            tp->len -= tp->owrite - retain;
            tp->owrite = 0;
            tp->insert += retain;
      }
}

/*
 * txt_nomorech --
 *    No more characters message.
 */
static void
txt_nomorech(sp)
      SCR *sp;
{
      msgq(sp, M_BERR, "194|No more characters to erase");
}

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