Return cursor y position even if vs_line is not drawing anything

[nvi.git] / vi / 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[] = "$Id: vs_line.c,v 10.33 2001/05/10 19:25:49 skimo Exp $ (Berkeley) $Date: 2001/05/10 19:25:49 $";
#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 *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 dne, is_cached, is_partial, is_tab, no_draw;
        int list_tab, list_dollar;
        CHAR_T *p;
        CHAR_T *cbp, *ecbp, cbuf[128];
        CHAR_T ch;

#if defined(DEBUG) && 0
        vtrace(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.
         */
        no_draw = 0;
        if (!F_ISSET(sp, SC_TINPUT_INFO) && VIP(sp)->totalcount > 1)
                no_draw = 1;
        if (F_ISSET(sp, SC_SCR_EXWROTE) && smp - HMAP != LASTLINE(sp))
                no_draw = 1;

        /*
         * 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 || no_draw))
                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((char*)cbuf,
                                    sizeof(cbuf), O_NUMBER_FMT, smp->lno);
                                (void)gp->scr_addstr(sp, (char*)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 || no_draw)
                        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 = L('$');
                                                goto empty;
                                        }
                                } else {
                                        ch = L('~');
                                        goto empty;
                                }
                        } else
                                if (list_dollar) {
                                        ch = L('$');
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 = *p++) == L('\t') && !list_tab ?
                            TAB_OFF(scno) : KEY_COL(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 = *p++) == L('\t') && !list_tab ?
                            TAB_OFF(scno) : KEY_COL(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 || no_draw)
                        goto ret1;
        } else
                cno_cnt = (sp->cno - offset_in_line) + 1;

        /* This is the loop that actually displays characters. */
        ecbp = (cbp = cbuf) + sizeof(cbuf)/sizeof(CHAR_T) - 1;
        for (is_partial = 0, scno = 0;
            offset_in_line < len; ++offset_in_line, offset_in_char = 0) {
                if ((ch = *p++) == L('\t') && !list_tab) {
                        scno += chlen = TAB_OFF(scno) - offset_in_char;
                        is_tab = 1;
                } else {
                        scno += chlen = KEY_COL(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))
                                if (is_partial)
                                        *xp = scno - smp->c_ecsize;
                                else
                                        *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 || no_draw)
                                goto ret1;
                }

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

#define FLUSH {                                                         \
        *cbp = '\0';                                                    \
        (void)gp->scr_waddstr(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;

                        /* don't display half a wide character */
                        if (is_partial && CHAR_WIDTH(sp, ch) > 1) {
                                *cbp++ = ' ';
                                break;
                        }

                        if (INTISWIDE(ch))
                                *cbp++ = ch;
                        else
                                for (kp = KEY_NAME(sp, ch) + offset_in_char; 
                                     chlen--;)
                                        *cbp++ = (u_char)*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);
}