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vs_line.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[] = "@(#)vs_line.c     10.19 (Berkeley) 9/26/96";
#endif /* not lint */

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

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

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

#ifdef VISIBLE_TAB_CHARS
#define     TABCH '-'
#else
#define     TABCH ' '
#endif

/*
 * vs_line --
 *    Update one line on the screen.
 *
 * PUBLIC: int vs_line __P((SCR *, SMAP *, size_t *, size_t *));
 */
int
vs_line(sp, smp, yp, xp)
      SCR *sp;
      SMAP *smp;
      size_t *xp, *yp;
{
      CHAR_T *kp;
      GS *gp;
      SMAP *tsmp;
      size_t chlen, cno_cnt, cols_per_screen, len, nlen;
      size_t offset_in_char, offset_in_line, oldx, oldy;
      size_t scno, skip_cols, skip_screens;
      int ch, dne, is_cached, is_partial, is_tab;
      int list_tab, list_dollar;
      char *p, *cbp, *ecbp, cbuf[128];

#if defined(DEBUG) && 0
      TRACE(sp, "vs_line: row %u: line: %u off: %u\n",
          smp - HMAP, smp->lno, smp->off);
#endif
      /*
       * If ex modifies the screen after ex output is already on the screen,
       * don't touch it -- we'll get scrolling wrong, at best.
       */
      if (!F_ISSET(sp, SC_TINPUT_INFO) && VIP(sp)->totalcount > 1)
            return (0);
      if (F_ISSET(sp, SC_SCR_EXWROTE) && smp - HMAP != LASTLINE(sp))
            return (0);

      /*
       * Assume that, if the cache entry for the line is filled in, the
       * line is already on the screen, and all we need to do is return
       * the cursor position.  If the calling routine doesn't need the
       * cursor position, we can just return.
       */
      is_cached = SMAP_CACHE(smp);
      if (yp == NULL && is_cached)
            return (0);

      /*
       * A nasty side effect of this routine is that it returns the screen
       * position for the "current" character.  Not pretty, but this is the
       * only routine that really knows what's out there.
       *
       * Move to the line.  This routine can be called by vs_sm_position(),
       * which uses it to fill in the cache entry so it can figure out what
       * the real contents of the screen are.  Because of this, we have to
       * return to whereever we started from.
       */
      gp = sp->gp;
      (void)gp->scr_cursor(sp, &oldy, &oldx);
      (void)gp->scr_move(sp, smp - HMAP, 0);

      /* Get the line. */
      dne = db_get(sp, smp->lno, 0, &p, &len);

      /*
       * Special case if we're printing the info/mode line.  Skip printing
       * the leading number, as well as other minor setup.  The only time
       * this code paints the mode line is when the user is entering text
       * for a ":" command, so we can put the code here instead of dealing
       * with the empty line logic below.  This is a kludge, but it's pretty
       * much confined to this module.
       *
       * Set the number of columns for this screen.
       * Set the number of chars or screens to skip until a character is to
       * be displayed.
       */
      cols_per_screen = sp->cols;
      if (O_ISSET(sp, O_LEFTRIGHT)) {
            skip_screens = 0;
            skip_cols = smp->coff;
      } else {
            skip_screens = smp->soff - 1;
            skip_cols = skip_screens * cols_per_screen;
      }

      list_tab = O_ISSET(sp, O_LIST);
      if (F_ISSET(sp, SC_TINPUT_INFO))
            list_dollar = 0;
      else {
            list_dollar = list_tab;

            /*
             * If O_NUMBER is set, the line doesn't exist and it's line
             * number 1, i.e., an empty file, display the line number.
             *
             * If O_NUMBER is set, the line exists and the first character
             * on the screen is the first character in the line, display
             * the line number.
             *
             * !!!
             * If O_NUMBER set, decrement the number of columns in the
             * first screen.  DO NOT CHANGE THIS -- IT'S RIGHT!  The
             * rest of the code expects this to reflect the number of
             * columns in the first screen, regardless of the number of
             * columns we're going to skip.
             */
            if (O_ISSET(sp, O_NUMBER)) {
                  cols_per_screen -= O_NUMBER_LENGTH;
                  if ((!dne || smp->lno == 1) && skip_cols == 0) {
                        nlen = snprintf(cbuf,
                            sizeof(cbuf), O_NUMBER_FMT, smp->lno);
                        (void)gp->scr_addstr(sp, cbuf, nlen);
                  }
            }
      }

      /*
       * Special case non-existent lines and the first line of an empty
       * file.  In both cases, the cursor position is 0, but corrected
       * as necessary for the O_NUMBER field, if it was displayed.
       */
      if (dne || len == 0) {
            /* Fill in the cursor. */
            if (yp != NULL && smp->lno == sp->lno) {
                  *yp = smp - HMAP;
                  *xp = sp->cols - cols_per_screen;
            }

            /* If the line is on the screen, quit. */
            if (is_cached)
                  goto ret1;

            /* Set line cache information. */
            smp->c_sboff = smp->c_eboff = 0;
            smp->c_scoff = smp->c_eclen = 0;

            /*
             * Lots of special cases for empty lines, but they only apply
             * if we're displaying the first screen of the line.
             */
            if (skip_cols == 0)
                  if (dne) {
                        if (smp->lno == 1) {
                              if (list_dollar) {
                                    ch = '$';
                                    goto empty;
                              }
                        } else {
                              ch = '~';
                              goto empty;
                        }
                  } else
                        if (list_dollar) {
                              ch = '$';
empty:                              (void)gp->scr_addstr(sp,
                                  KEY_NAME(sp, ch), KEY_LEN(sp, ch));
                        }

            (void)gp->scr_clrtoeol(sp);
            (void)gp->scr_move(sp, oldy, oldx);
            return (0);
      }

      /*
       * If we just wrote this or a previous line, we cached the starting
       * and ending positions of that line.  The way it works is we keep
       * information about the lines displayed in the SMAP.  If we're
       * painting the screen in the forward direction, this saves us from
       * reformatting the physical line for every line on the screen.  This
       * wins big on binary files with 10K lines.
       *
       * Test for the first screen of the line, then the current screen line,
       * then the line behind us, then do the hard work.  Note, it doesn't
       * do us any good to have a line in front of us -- it would be really
       * hard to try and figure out tabs in the reverse direction, i.e. how
       * many spaces a tab takes up in the reverse direction depends on
       * what characters preceded it.
       *
       * Test for the first screen of the line.
       */
      if (skip_cols == 0) {
            smp->c_sboff = offset_in_line = 0;
            smp->c_scoff = offset_in_char = 0;
            p = &p[offset_in_line];
            goto display;
      }

      /* Test to see if we've seen this exact line before. */
      if (is_cached) {
            offset_in_line = smp->c_sboff;
            offset_in_char = smp->c_scoff;
            p = &p[offset_in_line];

            /* Set cols_per_screen to 2nd and later line length. */
            if (O_ISSET(sp, O_LEFTRIGHT) || skip_cols > cols_per_screen)
                  cols_per_screen = sp->cols;
            goto display;
      }

      /* Test to see if we saw an earlier part of this line before. */
      if (smp != HMAP &&
          SMAP_CACHE(tsmp = smp - 1) && tsmp->lno == smp->lno) {
            if (tsmp->c_eclen != tsmp->c_ecsize) {
                  offset_in_line = tsmp->c_eboff;
                  offset_in_char = tsmp->c_eclen;
            } else {
                  offset_in_line = tsmp->c_eboff + 1;
                  offset_in_char = 0;
            }

            /* Put starting info for this line in the cache. */
            smp->c_sboff = offset_in_line;
            smp->c_scoff = offset_in_char;
            p = &p[offset_in_line];

            /* Set cols_per_screen to 2nd and later line length. */
            if (O_ISSET(sp, O_LEFTRIGHT) || skip_cols > cols_per_screen)
                  cols_per_screen = sp->cols;
            goto display;
      }

      scno = 0;
      offset_in_line = 0;
      offset_in_char = 0;

      /* Do it the hard way, for leftright scrolling screens. */
      if (O_ISSET(sp, O_LEFTRIGHT)) {
            for (; offset_in_line < len; ++offset_in_line) {
                  chlen = (ch = *(u_char *)p++) == '\t' && !list_tab ?
                      TAB_OFF(scno) : KEY_LEN(sp, ch);
                  if ((scno += chlen) >= skip_cols)
                        break;
            }

            /* Set cols_per_screen to 2nd and later line length. */
            cols_per_screen = sp->cols;

            /* Put starting info for this line in the cache. */
            if (scno != skip_cols) {
                  smp->c_sboff = offset_in_line;
                  smp->c_scoff =
                      offset_in_char = chlen - (scno - skip_cols);
                  --p;
            } else {
                  smp->c_sboff = ++offset_in_line;
                  smp->c_scoff = 0;
            }
      }

      /* Do it the hard way, for historic line-folding screens. */
      else {
            for (; offset_in_line < len; ++offset_in_line) {
                  chlen = (ch = *(u_char *)p++) == '\t' && !list_tab ?
                      TAB_OFF(scno) : KEY_LEN(sp, ch);
                  if ((scno += chlen) < cols_per_screen)
                        continue;
                  scno -= cols_per_screen;

                  /* Set cols_per_screen to 2nd and later line length. */
                  cols_per_screen = sp->cols;

                  /*
                   * If crossed the last skipped screen boundary, start
                   * displaying the characters.
                   */
                  if (--skip_screens == 0)
                        break;
            }

            /* Put starting info for this line in the cache. */
            if (scno != 0) {
                  smp->c_sboff = offset_in_line;
                  smp->c_scoff = offset_in_char = chlen - scno;
                  --p;
            } else {
                  smp->c_sboff = ++offset_in_line;
                  smp->c_scoff = 0;
            }
      }

display:
      /*
       * Set the number of characters to skip before reaching the cursor
       * character.  Offset by 1 and use 0 as a flag value.  Vs_line is
       * called repeatedly with a valid pointer to a cursor position.
       * Don't fill anything in unless it's the right line and the right
       * character, and the right part of the character...
       */
      if (yp == NULL ||
          smp->lno != sp->lno || sp->cno < offset_in_line ||
          offset_in_line + cols_per_screen < sp->cno) {
            cno_cnt = 0;
            /* If the line is on the screen, quit. */
            if (is_cached)
                  goto ret1;
      } else
            cno_cnt = (sp->cno - offset_in_line) + 1;

      /* This is the loop that actually displays characters. */
      ecbp = (cbp = cbuf) + sizeof(cbuf) - 1;
      for (is_partial = 0, scno = 0;
          offset_in_line < len; ++offset_in_line, offset_in_char = 0) {
            if ((ch = *(u_char *)p++) == '\t' && !list_tab) {
                  scno += chlen = TAB_OFF(scno) - offset_in_char;
                  is_tab = 1;
            } else {
                  scno += chlen = KEY_LEN(sp, ch) - offset_in_char;
                  is_tab = 0;
            }

            /*
             * Only display up to the right-hand column.  Set a flag if
             * the entire character wasn't displayed for use in setting
             * the cursor.  If reached the end of the line, set the cache
             * info for the screen.  Don't worry about there not being
             * characters to display on the next screen, its lno/off won't
             * match up in that case.
             */
            if (scno >= cols_per_screen) {
                  if (is_tab == 1) {
                        chlen -= scno - cols_per_screen;
                        smp->c_ecsize = smp->c_eclen = chlen;
                        scno = cols_per_screen;
                  } else {
                        smp->c_ecsize = chlen;
                        chlen -= scno - cols_per_screen;
                        smp->c_eclen = chlen;

                        if (scno > cols_per_screen)
                              is_partial = 1;
                  }
                  smp->c_eboff = offset_in_line;

                  /* Terminate the loop. */
                  offset_in_line = len;
            }

            /*
             * If the caller wants the cursor value, and this was the
             * cursor character, set the value.  There are two ways to
             * put the cursor on a character -- if it's normal display
             * mode, it goes on the last column of the character.  If
             * it's input mode, it goes on the first.  In normal mode,
             * set the cursor only if the entire character was displayed.
             */
            if (cno_cnt &&
                --cno_cnt == 0 && (F_ISSET(sp, SC_TINPUT) || !is_partial)) {
                  *yp = smp - HMAP;
                  if (F_ISSET(sp, SC_TINPUT))
                        *xp = scno - chlen;
                  else
                        *xp = scno - 1;
                  if (O_ISSET(sp, O_NUMBER) &&
                      !F_ISSET(sp, SC_TINPUT_INFO) && skip_cols == 0)
                        *xp += O_NUMBER_LENGTH;

                  /* If the line is on the screen, quit. */
                  if (is_cached)
                        goto ret1;
            }

            /* If the line is on the screen, don't display anything. */
            if (is_cached)
                  continue;

#define     FLUSH {                                               \
      *cbp = '\0';                                          \
      (void)gp->scr_addstr(sp, cbuf, cbp - cbuf);                 \
      cbp = cbuf;                                     \
}
            /*
             * Display the character.  We do tab expansion here because
             * the screen interface doesn't have any way to set the tab
             * length.  Note, it's theoretically possible for chlen to
             * be larger than cbuf, if the user set a impossibly large
             * tabstop.
             */
            if (is_tab)
                  while (chlen--) {
                        if (cbp >= ecbp)
                              FLUSH;
                        *cbp++ = TABCH;
                  }
            else {
                  if (cbp + chlen >= ecbp)
                        FLUSH;
                  for (kp = KEY_NAME(sp, ch) + offset_in_char; chlen--;)
                        *cbp++ = *kp++;
            }
      }

      if (scno < cols_per_screen) {
            /* If didn't paint the whole line, update the cache. */
            smp->c_ecsize = smp->c_eclen = KEY_LEN(sp, ch);
            smp->c_eboff = len - 1;

            /*
             * If not the info/mode line, and O_LIST set, and at the
             * end of the line, and the line ended on this screen,
             * add a trailing $.
             */
            if (list_dollar) {
                  ++scno;

                  chlen = KEY_LEN(sp, '$');
                  if (cbp + chlen >= ecbp)
                        FLUSH;
                  for (kp = KEY_NAME(sp, '$'); chlen--;)
                        *cbp++ = *kp++;
            }

            /* If still didn't paint the whole line, clear the rest. */
            if (scno < cols_per_screen)
                  (void)gp->scr_clrtoeol(sp);
      }

      /* Flush any buffered characters. */
      if (cbp > cbuf)
            FLUSH;

ret1: (void)gp->scr_move(sp, oldy, oldx);
      return (0);
}

/*
 * vs_number --
 *    Repaint the numbers on all the lines.
 *
 * PUBLIC: int vs_number __P((SCR *));
 */
int
vs_number(sp)
      SCR *sp;
{
      GS *gp;
      SMAP *smp;
      VI_PRIVATE *vip;
      size_t len, oldy, oldx;
      int exist;
      char nbuf[10];

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

      /* No reason to do anything if we're in input mode on the info line. */
      if (F_ISSET(sp, SC_TINPUT_INFO))
            return (0);

      /*
       * Try and avoid getting the last line in the file, by getting the
       * line after the last line in the screen -- if it exists, we know
       * we have to to number all the lines in the screen.  Get the one
       * after the last instead of the last, so that the info line doesn't
       * fool us.  (The problem is that file_lline will lie, and tell us
       * that the info line is the last line in the file.) If that test
       * fails, we have to check each line for existence.
       */
      exist = db_exist(sp, TMAP->lno + 1);

      (void)gp->scr_cursor(sp, &oldy, &oldx);
      for (smp = HMAP; smp <= TMAP; ++smp) {
            /* Numbers are only displayed for the first screen line. */
            if (O_ISSET(sp, O_LEFTRIGHT)) {
                  if (smp->coff != 0)
                        continue;
            } else
                  if (smp->soff != 1)
                        continue;

            /*
             * The first line of an empty file gets numbered, otherwise
             * number any existing line.
             */
            if (smp->lno != 1 && !exist && !db_exist(sp, smp->lno))
                  break;

            (void)gp->scr_move(sp, smp - HMAP, 0);
            len = snprintf(nbuf, sizeof(nbuf), O_NUMBER_FMT, smp->lno);
            (void)gp->scr_addstr(sp, nbuf, len);
      }
      (void)gp->scr_move(sp, oldy, oldx);
      return (0);
}

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