/* $OpenBSD: tbl_term.c,v 1.68 2025/07/24 17:51:00 schwarze Exp $ */
/*
 * Copyright (c) 2011-2022, 2025 Ingo Schwarze <schwarze@openbsd.org>
 * Copyright (c) 2009, 2011 Kristaps Dzonsons <kristaps@bsd.lv>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */
#include <sys/types.h>

#include <assert.h>
#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "mandoc.h"
#include "tbl.h"
#include "out.h"
#include "term.h"

#define IS_HORIZ(cp)    ((cp)->pos == TBL_CELL_HORIZ || \
                         (cp)->pos == TBL_CELL_DHORIZ)


static  size_t  term_tbl_len(size_t, void *);
static  size_t  term_tbl_strlen(const char *, void *);
static  void    tbl_data(struct termp *, const struct tbl_opts *,
                        const struct tbl_cell *,
                        const struct tbl_dat *,
                        const struct roffcol *, size_t *);
static  void    tbl_direct_border(struct termp *, int, size_t);
static  void    tbl_fill_border(struct termp *, int, size_t *, size_t);
static  void    tbl_fill_char(struct termp *, char, size_t *, size_t);
static  void    tbl_fill_string(struct termp *, const char *,
                        size_t *, size_t);
static  void    tbl_hrule(struct termp *, const struct tbl_span *,
                        const struct tbl_span *, const struct tbl_span *,
                        int);
static  void    tbl_literal(struct termp *, const struct tbl_dat *,
                        const struct roffcol *, size_t *);
static  void    tbl_number(struct termp *, const struct tbl_opts *,
                        const struct tbl_dat *,
                        const struct roffcol *, size_t *);
static  void    tbl_word(struct termp *, const struct tbl_dat *);


/*
 * The following border-character tables are indexed
 * by ternary (3-based) numbers, as opposed to binary or decimal.
 * Each ternary digit describes the line width in one direction:
 * 0 means no line, 1 single or light line, 2 double or heavy line.
 */

/* Positional values of the four directions. */
#define BRIGHT  1
#define BDOWN   3
#define BLEFT   (3 * 3)
#define BUP     (3 * 3 * 3)
#define BHORIZ  (BLEFT + BRIGHT)

/* Code points to use for each combination of widths. */
static  const int borders_utf8[81] = {
        0x0020, 0x2576, 0x257a,  /* 000 right */
        0x2577, 0x250c, 0x250d,  /* 001 down */
        0x257b, 0x250e, 0x250f,  /* 002 */
        0x2574, 0x2500, 0x257c,  /* 010 left */
        0x2510, 0x252c, 0x252e,  /* 011 left down */
        0x2512, 0x2530, 0x2532,  /* 012 */
        0x2578, 0x257e, 0x2501,  /* 020 left */
        0x2511, 0x252d, 0x252f,  /* 021 left down */
        0x2513, 0x2531, 0x2533,  /* 022 */
        0x2575, 0x2514, 0x2515,  /* 100 up */
        0x2502, 0x251c, 0x251d,  /* 101 up down */
        0x257d, 0x251f, 0x2522,  /* 102 */
        0x2518, 0x2534, 0x2536,  /* 110 up left */
        0x2524, 0x253c, 0x253e,  /* 111 all */
        0x2527, 0x2541, 0x2546,  /* 112 */
        0x2519, 0x2535, 0x2537,  /* 120 up left */
        0x2525, 0x253d, 0x253f,  /* 121 all */
        0x252a, 0x2545, 0x2548,  /* 122 */
        0x2579, 0x2516, 0x2517,  /* 200 up */
        0x257f, 0x251e, 0x2521,  /* 201 up down */
        0x2503, 0x2520, 0x2523,  /* 202 */
        0x251a, 0x2538, 0x253a,  /* 210 up left */
        0x2526, 0x2540, 0x2544,  /* 211 all */
        0x2528, 0x2542, 0x254a,  /* 212 */
        0x251b, 0x2539, 0x253b,  /* 220 up left */
        0x2529, 0x2543, 0x2547,  /* 221 all */
        0x252b, 0x2549, 0x254b,  /* 222 */
};

/* ASCII approximations for these code points, compatible with groff. */
static  const int borders_ascii[81] = {
        ' ', '-', '=',  /* 000 right */
        '|', '+', '+',  /* 001 down */
        '|', '+', '+',  /* 002 */
        '-', '-', '=',  /* 010 left */
        '+', '+', '+',  /* 011 left down */
        '+', '+', '+',  /* 012 */
        '=', '=', '=',  /* 020 left */
        '+', '+', '+',  /* 021 left down */
        '+', '+', '+',  /* 022 */
        '|', '+', '+',  /* 100 up */
        '|', '+', '+',  /* 101 up down */
        '|', '+', '+',  /* 102 */
        '+', '+', '+',  /* 110 up left */
        '+', '+', '+',  /* 111 all */
        '+', '+', '+',  /* 112 */
        '+', '+', '+',  /* 120 up left */
        '+', '+', '+',  /* 121 all */
        '+', '+', '+',  /* 122 */
        '|', '+', '+',  /* 200 up */
        '|', '+', '+',  /* 201 up down */
        '|', '+', '+',  /* 202 */
        '+', '+', '+',  /* 210 up left */
        '+', '+', '+',  /* 211 all */
        '+', '+', '+',  /* 212 */
        '+', '+', '+',  /* 220 up left */
        '+', '+', '+',  /* 221 all */
        '+', '+', '+',  /* 222 */
};

/* Either of the above according to the selected output encoding. */
static  const int *borders_locale;


static size_t
term_tbl_strlen(const char *p, void *arg)
{
        return term_strlen((const struct termp *)arg, p);
}

static size_t
term_tbl_len(size_t sz, void *arg)
{
        return term_len((const struct termp *)arg, sz);
}


void
term_tbl(struct termp *tp, const struct tbl_span *sp)
{
        const struct tbl_cell   *cp, *cpn, *cpp, *cps;
        const struct tbl_dat    *dp;

        /* Positions and widths in basic units. */
        static size_t    offset;        /* Of the table as a whole. */
        size_t           save_offset;   /* Of the surrounding text. */
        size_t           coloff;        /* Of this cell. */
        size_t           tsz;           /* Total width of the table. */
        size_t           enw;           /* Width of one EN unit. */

        int      ic;     /* Column number. */
        int      hspans; /* Number of spans following this cell. */
        int      horiz;  /* Boolean: this row only contains a line. */
        int      lhori;  /* Number of horizontal lines pointing left. */
        int      rhori;  /* Number of horizontal lines pointing right. */
        int      dvert;  /* Number of vertical lines pointing down. */
        int      uvert;  /* Number of vertical lines pointing up. */
        int      fc;     /* Frame character index in borders_locale[]. */
        int      more;   /* Boolean: there are more columns to print. */

        /* Inhibit printing of spaces: we do padding ourselves. */

        tp->flags |= TERMP_NOSPACE | TERMP_NONOSPACE;
        save_offset = tp->tcol->offset;
        enw = term_len(tp, 1);

        /*
         * The first time we're invoked for a given table block,
         * calculate the table widths and decimal positions.
         */

        if (tp->tbl.cols == NULL) {
                borders_locale = tp->enc == TERMENC_UTF8 ?
                    borders_utf8 : borders_ascii;

                tp->tbl.len = term_tbl_len;
                tp->tbl.slen = term_tbl_strlen;
                tp->tbl.arg = tp;

                tblcalc(&tp->tbl, sp, tp->tcol->offset, tp->tcol->rmargin);

                /* Center the table as a whole. */

                offset = tp->tcol->offset;
                if (sp->opts->opts & TBL_OPT_CENTRE) {

                        /*
                         * Vertical lines on the edges of the table make the
                         * table wider; take that into account for centering.
                         * The following assignment essentially says that a
                         * line on the right side occupies two columns (which
                         * matches reality) and a line on the left side three
                         * columns (which does not match reality; in fact,
                         * it only occupies two columns).  But this is how
                         * groff does centering, so for compatibility, use
                         * the same numbers as groff.
                         */

                        tsz = term_len(tp,
                            sp->opts->opts & (TBL_OPT_BOX | TBL_OPT_DBOX) ?
                            5 : 3 * !!sp->opts->lvert + 2 * !!sp->opts->rvert);

                        /* Column widths and column spacing. */

                        for (ic = 0; ic + 1 < sp->opts->cols; ic++)
                                tsz += tp->tbl.cols[ic].width +
                                    term_len(tp, tp->tbl.cols[ic].spacing);
                        if (sp->opts->cols)
                                tsz += tp->tbl.cols[sp->opts->cols - 1].width;

                        if (offset + tsz > tp->tcol->rmargin)
                                tsz -= enw;
                        offset = offset + tp->tcol->rmargin > tsz ?
                            ((offset + tp->tcol->rmargin - tsz) / enw / 2) *
                            enw : 0;
                        tp->tcol->offset = offset;
                }

                /* Horizontal frame at the start of boxed tables. */

                if (tp->enc == TERMENC_ASCII &&
                    sp->opts->opts & TBL_OPT_DBOX)
                        tbl_hrule(tp, NULL, sp, sp, TBL_OPT_DBOX);
                if (sp->opts->opts & (TBL_OPT_DBOX | TBL_OPT_BOX))
                        tbl_hrule(tp, NULL, sp, sp, TBL_OPT_BOX);
        }

        /* Set up the columns. */

        tp->flags |= TERMP_MULTICOL;
        tp->tcol->offset = offset;
        horiz = 0;
        switch (sp->pos) {
        case TBL_SPAN_HORIZ:
        case TBL_SPAN_DHORIZ:
                horiz = 1;
                term_setcol(tp, 1);
                break;
        case TBL_SPAN_DATA:
                term_setcol(tp, sp->opts->cols + 2);
                coloff = tp->tcol->offset;

                /* Set up a column for a left vertical frame. */

                if (sp->opts->opts & (TBL_OPT_BOX | TBL_OPT_DBOX) ||
                    sp->opts->lvert)
                        coloff += enw * 2;
                tp->tcol->rmargin = coloff;

                /* Set up the data columns. */

                dp = sp->first;
                hspans = 0;
                for (ic = 0; ic < sp->opts->cols; ic++) {
                        if (hspans == 0) {
                                tp->tcol++;
                                tp->tcol->offset = coloff;
                        }
                        coloff += tp->tbl.cols[ic].width;
                        tp->tcol->rmargin = coloff;
                        if (ic + 1 < sp->opts->cols)
                                coloff += term_len(tp,
                                    tp->tbl.cols[ic].spacing);
                        if (hspans) {
                                hspans--;
                                continue;
                        }
                        if (dp != NULL &&
                            (ic || sp->layout->first->pos != TBL_CELL_SPAN)) {
                                hspans = dp->hspans;
                                dp = dp->next;
                        }
                }

                /* Set up a column for a right vertical frame. */

                tp->tcol++;
                tp->tcol->offset = coloff + enw;
                tp->tcol->rmargin = tp->maxrmargin;

                /* Spans may have reduced the number of columns. */

                tp->lasttcol = tp->tcol - tp->tcols;

                /* Fill the buffers for all data columns. */

                tp->tcol = tp->tcols;
                coloff = tp->tcols[1].offset;
                cp = cpn = sp->layout->first;
                dp = sp->first;
                hspans = 0;
                for (ic = 0; ic < sp->opts->cols; ic++) {
                        if (cpn != NULL) {
                                cp = cpn;
                                cpn = cpn->next;
                        }
                        if (hspans) {
                                hspans--;
                                continue;
                        }
                        tp->tcol++;
                        tp->col = 0;
                        tp->flags &= ~(TERMP_BACKAFTER | TERMP_BACKBEFORE);
                        tbl_data(tp, sp->opts, cp, dp, tp->tbl.cols + ic,
                            &coloff);
                        coloff += term_len(tp, tp->tbl.cols[ic].spacing);
                        if (dp != NULL &&
                            (ic || sp->layout->first->pos != TBL_CELL_SPAN)) {
                                hspans = dp->hspans;
                                dp = dp->next;
                        }
                }
                break;
        }

        do {
                /* Print the vertical frame at the start of each row. */

                tp->tcol = tp->tcols;
                uvert = dvert = sp->opts->opts & TBL_OPT_DBOX ? 2 :
                    sp->opts->opts & TBL_OPT_BOX ? 1 : 0;
                if (sp->pos == TBL_SPAN_DATA && uvert < sp->layout->vert)
                        uvert = dvert = sp->layout->vert;
                if (sp->next != NULL && sp->next->pos == TBL_SPAN_DATA &&
                    dvert < sp->next->layout->vert)
                        dvert = sp->next->layout->vert;
                if (sp->prev != NULL && uvert < sp->prev->layout->vert &&
                    (horiz || (IS_HORIZ(sp->layout->first) &&
                      !IS_HORIZ(sp->prev->layout->first))))
                        uvert = sp->prev->layout->vert;
                rhori = sp->pos == TBL_SPAN_DHORIZ ||
                    (sp->first != NULL && sp->first->pos == TBL_DATA_DHORIZ) ||
                    sp->layout->first->pos == TBL_CELL_DHORIZ ? 2 :
                    sp->pos == TBL_SPAN_HORIZ ||
                    (sp->first != NULL && sp->first->pos == TBL_DATA_HORIZ) ||
                    sp->layout->first->pos == TBL_CELL_HORIZ ? 1 : 0;
                fc = BUP * uvert + BDOWN * dvert + BRIGHT * rhori;
                if (uvert > 0 || dvert > 0 || (horiz && sp->opts->lvert)) {
                        (*tp->advance)(tp, tp->tcols->offset);
                        tbl_direct_border(tp, fc, enw);
                        tbl_direct_border(tp, BHORIZ * rhori, enw);
                }

                /* Print the data cells. */

                more = 0;
                if (horiz)
                        tbl_hrule(tp, sp->prev, sp, sp->next, 0);
                else {
                        cp = sp->layout->first;
                        cpn = sp->next == NULL ? NULL :
                            sp->next->layout->first;
                        cpp = sp->prev == NULL ? NULL :
                            sp->prev->layout->first;
                        dp = sp->first;
                        hspans = 0;
                        for (ic = 0; ic < sp->opts->cols; ic++) {

                                /*
                                 * Handle horizontal alignment.
                                 * Figure out whether to print a
                                 * vertical line after this cell
                                 * and advance to next layout cell.
                                 */

                                uvert = dvert = fc = 0;
                                if (cp != NULL) {
                                        cps = cp;
                                        while (cps->next != NULL &&
                                            cps->next->pos == TBL_CELL_SPAN)
                                                cps = cps->next;
                                        if (sp->pos == TBL_SPAN_DATA)
                                                uvert = dvert = cps->vert;
                                        switch (cp->pos) {
                                        case TBL_CELL_CENTRE:
                                                tp->flags |= TERMP_CENTER;
                                                break;
                                        case TBL_CELL_RIGHT:
                                                tp->flags |= TERMP_RIGHT;
                                                break;
                                        case TBL_CELL_LONG:
                                                if (hspans == 0)
                                                        tp->tcol->offset += enw;
                                                break;
                                        case TBL_CELL_HORIZ:
                                                fc = BHORIZ;
                                                break;
                                        case TBL_CELL_DHORIZ:
                                                fc = BHORIZ * 2;
                                                break;
                                        default:
                                                break;
                                        }
                                }
                                if (cpp != NULL) {
                                        if (uvert < cpp->vert &&
                                            cp != NULL &&
                                            ((IS_HORIZ(cp) &&
                                              !IS_HORIZ(cpp)) ||
                                             (cp->next != NULL &&
                                              cpp->next != NULL &&
                                              IS_HORIZ(cp->next) &&
                                              !IS_HORIZ(cpp->next))))
                                                uvert = cpp->vert;
                                        cpp = cpp->next;
                                }
                                if (sp->opts->opts & TBL_OPT_ALLBOX) {
                                        if (uvert == 0)
                                                uvert = 1;
                                        if (dvert == 0)
                                                dvert = 1;
                                }
                                if (cpn != NULL) {
                                        if (dvert == 0 ||
                                            (dvert < cpn->vert &&
                                             tp->enc == TERMENC_UTF8))
                                                dvert = cpn->vert;
                                        cpn = cpn->next;
                                }

                                lhori = (cp != NULL &&
                                     cp->pos == TBL_CELL_DHORIZ) ||
                                    (dp != NULL &&
                                     dp->pos == TBL_DATA_DHORIZ) ? 2 :
                                    (cp != NULL &&
                                     cp->pos == TBL_CELL_HORIZ) ||
                                    (dp != NULL &&
                                     dp->pos == TBL_DATA_HORIZ) ? 1 : 0;

                                /*
                                 * Skip later cells in a span,
                                 * figure out whether to start a span,
                                 * and advance to next data cell.
                                 */

                                if (hspans) {
                                        hspans--;
                                        cp = cp->next;
                                        continue;
                                }
                                if (dp != NULL && (ic ||
                                    sp->layout->first->pos != TBL_CELL_SPAN)) {
                                        hspans = dp->hspans;
                                        dp = dp->next;
                                }

                                /*
                                 * Print one line of text in the cell
                                 * and remember whether there is more.
                                 */

                                tp->tcol++;
                                if (tp->tcol->col < tp->tcol->lastcol)
                                        term_flushln(tp);
                                tp->flags &= ~(TERMP_CENTER | TERMP_RIGHT);
                                if (cp != NULL && cp->pos == TBL_CELL_LONG)
                                        tp->tcol->offset -= enw;
                                if (tp->tcol->col < tp->tcol->lastcol)
                                        more = 1;

                                /*
                                 * Vertical frames between data cells,
                                 * but not after the last column.
                                 */

                                if (fc == 0 &&
                                    ((uvert == 0 && dvert == 0 &&
                                      cp != NULL && (cp->next == NULL ||
                                      !IS_HORIZ(cp->next))) ||
                                     tp->tcol + 1 ==
                                      tp->tcols + tp->lasttcol)) {
                                        if (cp != NULL)
                                                cp = cp->next;
                                        continue;
                                }

                                if (tp->viscol < tp->tcol->rmargin)
                                        (*tp->advance)(tp,
                                           tp->tcol->rmargin - tp->viscol);
                                while (tp->viscol < tp->tcol->rmargin +
                                    term_len(tp, tp->tbl.cols[ic].spacing / 2))
                                        tbl_direct_border(tp,
                                            BHORIZ * lhori, enw);

                                if (tp->tcol + 1 == tp->tcols + tp->lasttcol)
                                        continue;

                                if (cp != NULL)
                                        cp = cp->next;

                                rhori = (cp != NULL &&
                                     cp->pos == TBL_CELL_DHORIZ) ||
                                    (dp != NULL &&
                                     dp->pos == TBL_DATA_DHORIZ) ? 2 :
                                    (cp != NULL &&
                                     cp->pos == TBL_CELL_HORIZ) ||
                                    (dp != NULL &&
                                     dp->pos == TBL_DATA_HORIZ) ? 1 : 0;

                                if (tp->tbl.cols[ic].spacing)
                                        tbl_direct_border(tp,
                                            BLEFT * lhori + BRIGHT * rhori +
                                            BUP * uvert + BDOWN * dvert, enw);

                                if (tp->enc == TERMENC_UTF8)
                                        uvert = dvert = 0;

                                if (tp->tbl.cols[ic].spacing > 2 &&
                                    (uvert > 1 || dvert > 1 || rhori))
                                        tbl_direct_border(tp,
                                            BHORIZ * rhori +
                                            BUP * (uvert > 1) +
                                            BDOWN * (dvert > 1), enw);
                        }
                }

                /* Print the vertical frame at the end of each row. */

                uvert = dvert = sp->opts->opts & TBL_OPT_DBOX ? 2 :
                    sp->opts->opts & TBL_OPT_BOX ? 1 : 0;
                if (sp->pos == TBL_SPAN_DATA &&
                    uvert < sp->layout->last->vert &&
                    sp->layout->last->col + 1 == sp->opts->cols)
                        uvert = dvert = sp->layout->last->vert;
                if (sp->next != NULL &&
                    dvert < sp->next->layout->last->vert &&
                    sp->next->layout->last->col + 1 == sp->opts->cols)
                        dvert = sp->next->layout->last->vert;
                if (sp->prev != NULL &&
                    uvert < sp->prev->layout->last->vert &&
                    sp->prev->layout->last->col + 1 == sp->opts->cols &&
                    (horiz || (IS_HORIZ(sp->layout->last) &&
                     !IS_HORIZ(sp->prev->layout->last))))
                        uvert = sp->prev->layout->last->vert;
                lhori = sp->pos == TBL_SPAN_DHORIZ ||
                    (sp->last != NULL &&
                     sp->last->pos == TBL_DATA_DHORIZ &&
                     sp->last->layout->col + 1 == sp->opts->cols) ||
                    (sp->layout->last->pos == TBL_CELL_DHORIZ &&
                     sp->layout->last->col + 1 == sp->opts->cols) ? 2 :
                    sp->pos == TBL_SPAN_HORIZ ||
                    (sp->last != NULL &&
                     sp->last->pos == TBL_DATA_HORIZ &&
                     sp->last->layout->col + 1 == sp->opts->cols) ||
                    (sp->layout->last->pos == TBL_CELL_HORIZ &&
                     sp->layout->last->col + 1 == sp->opts->cols) ? 1 : 0;
                fc = BUP * uvert + BDOWN * dvert + BLEFT * lhori;
                if (uvert > 0 || dvert > 0 || (horiz && sp->opts->rvert)) {
                        if (horiz == 0 && (IS_HORIZ(sp->layout->last) == 0 ||
                            sp->layout->last->col + 1 < sp->opts->cols)) {
                                tp->tcol++;
                                if (tp->tcol->offset > tp->viscol)
                                        tbl_direct_border(tp,
                                            BHORIZ * lhori,
                                            tp->tcol->offset - tp->viscol);
                        }
                        tbl_direct_border(tp, fc, enw);
                }
                (*tp->endline)(tp);
        } while (more);

        /*
         * Clean up after this row.  If it is the last line
         * of the table, print the box line and clean up
         * column data; otherwise, print the allbox line.
         */

        term_setcol(tp, 1);
        tp->flags &= ~TERMP_MULTICOL;
        tp->tcol->rmargin = tp->maxrmargin;
        if (sp->next == NULL) {
                if (sp->opts->opts & (TBL_OPT_DBOX | TBL_OPT_BOX))
                        tbl_hrule(tp, sp, sp, NULL, TBL_OPT_BOX);
                if (tp->enc == TERMENC_ASCII &&
                    sp->opts->opts & TBL_OPT_DBOX)
                        tbl_hrule(tp, sp, sp, NULL, TBL_OPT_DBOX);
                assert(tp->tbl.cols);
                free(tp->tbl.cols);
                tp->tbl.cols = NULL;
        } else if (horiz == 0 && sp->opts->opts & TBL_OPT_ALLBOX &&
            (sp->next == NULL || sp->next->pos == TBL_SPAN_DATA ||
             sp->next->next != NULL))
                tbl_hrule(tp, sp, sp, sp->next, TBL_OPT_ALLBOX);

        tp->tcol->offset = save_offset;
        tp->flags &= ~TERMP_NONOSPACE;
}

static void
tbl_hrule(struct termp *tp, const struct tbl_span *spp,
    const struct tbl_span *sp, const struct tbl_span *spn, int flags)
{
        const struct tbl_cell   *cpp;    /* Layout cell above this line. */
        const struct tbl_cell   *cp;     /* Layout cell in this line. */
        const struct tbl_cell   *cpn;    /* Layout cell below this line. */
        const struct tbl_dat    *dpn;    /* Data cell below this line. */
        const struct roffcol    *col;    /* Contains width and spacing. */
        size_t                   enw;    /* Width of one EN unit. */
        int                      opts;   /* For the table as a whole. */
        int                      bw;     /* Box line width. */
        int                      hw;     /* Horizontal line width. */
        int                      lw, rw; /* Left and right line widths. */
        int                      uw, dw; /* Vertical line widths. */

        cpp = spp == NULL ? NULL : spp->layout->first;
        cp  = sp  == NULL ? NULL : sp->layout->first;
        cpn = spn == NULL ? NULL : spn->layout->first;
        dpn = NULL;
        if (spn != NULL) {
                if (spn->pos == TBL_SPAN_DATA)
                        dpn = spn->first;
                else if (spn->next != NULL)
                        dpn = spn->next->first;
        }
        opts = sp->opts->opts;
        bw = opts & TBL_OPT_DBOX ? (tp->enc == TERMENC_UTF8 ? 2 : 1) :
            opts & (TBL_OPT_BOX | TBL_OPT_ALLBOX) ? 1 : 0;
        hw = flags == TBL_OPT_DBOX || flags == TBL_OPT_BOX ? bw :
            sp->pos == TBL_SPAN_DHORIZ ? 2 : 1;

        /* Print the left end of the line. */

        enw = term_len(tp, 1);
        if (tp->viscol == 0)
                (*tp->advance)(tp, tp->tcols->offset);
        if (flags != 0) {
                tbl_direct_border(tp,
                    (spp == NULL ? 0 : BUP * bw) +
                    (spn == NULL ? 0 : BDOWN * bw) +
                    (spp == NULL || cpn == NULL ||
                     cpn->pos != TBL_CELL_DOWN ? BRIGHT * hw : 0), enw);
                tbl_direct_border(tp,
                    (spp == NULL || cpn == NULL ||
                     cpn->pos != TBL_CELL_DOWN ? BHORIZ * hw : 0), enw);
        }

        col = tp->tbl.cols;
        for (;;) {
                if (cp == NULL)
                        col++;
                else
                        col = tp->tbl.cols + cp->col;

                /* Print the horizontal line inside this column. */

                lw = cpp == NULL || cpn == NULL ||
                    (cpn->pos != TBL_CELL_DOWN &&
                     (dpn == NULL || dpn->string == NULL ||
                      strcmp(dpn->string, "\\^") != 0))
                    ? hw : 0;
                tbl_direct_border(tp, BHORIZ * lw,
                    col->width + term_len(tp, col->spacing / 2));

                /*
                 * Figure out whether a vertical line is crossing
                 * at the end of this column,
                 * and advance to the next column.
                 */

                uw = dw = 0;
                if (cpp != NULL) {
                        if (flags != TBL_OPT_DBOX) {
                                uw = cpp->vert;
                                if (uw == 0 && opts & TBL_OPT_ALLBOX)
                                        uw = 1;
                        }
                        cpp = cpp->next;
                } else if (spp != NULL && opts & TBL_OPT_ALLBOX)
                        uw = 1;
                if (cp != NULL)
                        cp = cp->next;
                if (cpn != NULL) {
                        if (flags != TBL_OPT_DBOX) {
                                dw = cpn->vert;
                                if (dw == 0 && opts & TBL_OPT_ALLBOX)
                                        dw = 1;
                        }
                        cpn = cpn->next;
                        while (dpn != NULL && dpn->layout != cpn)
                                dpn = dpn->next;
                } else if (spn != NULL && opts & TBL_OPT_ALLBOX)
                        dw = 1;
                if (col + 1 == tp->tbl.cols + sp->opts->cols)
                        break;

                /* Vertical lines do not cross spanned cells. */

                if (cpp != NULL && cpp->pos == TBL_CELL_SPAN)
                        uw = 0;
                if (cpn != NULL && cpn->pos == TBL_CELL_SPAN)
                        dw = 0;

                /* The horizontal line inside the next column. */

                rw = cpp == NULL || cpn == NULL ||
                    (cpn->pos != TBL_CELL_DOWN &&
                     (dpn == NULL || dpn->string == NULL ||
                      strcmp(dpn->string, "\\^") != 0))
                    ? hw : 0;

                /* The line crossing at the end of this column. */

                if (col->spacing)
                        tbl_direct_border(tp, BLEFT * lw +
                            BRIGHT * rw + BUP * uw + BDOWN * dw, enw);

                /*
                 * In ASCII output, a crossing may print two characters.
                 */

                if (tp->enc != TERMENC_ASCII || (uw < 2 && dw < 2))
                        uw = dw = 0;
                if (col->spacing > 2)
                        tbl_direct_border(tp,
                            BHORIZ * rw + BUP * uw + BDOWN * dw, enw);

                /* Padding before the start of the next column. */

                if (col->spacing > 4)
                        tbl_direct_border(tp,
                            BHORIZ * rw,
                            term_len(tp, (col->spacing - 3) / 2));
        }

        /* Print the right end of the line. */

        if (flags != 0) {
                tbl_direct_border(tp,
                    (spp == NULL ? 0 : BUP * bw) +
                    (spn == NULL ? 0 : BDOWN * bw) +
                    (spp == NULL || spn == NULL ||
                     spn->layout->last->pos != TBL_CELL_DOWN ?
                     BLEFT * hw : 0), enw);
                (*tp->endline)(tp);
        }
}

static void
tbl_data(struct termp *tp, const struct tbl_opts *opts,
    const struct tbl_cell *cp, const struct tbl_dat *dp,
    const struct roffcol *col, size_t *coloff)
{
        switch (cp->pos) {
        case TBL_CELL_HORIZ:
                tbl_fill_border(tp, BHORIZ, coloff, col->width);
                return;
        case TBL_CELL_DHORIZ:
                tbl_fill_border(tp, BHORIZ * 2, coloff, col->width);
                return;
        default:
                break;
        }

        if (dp == NULL)
                return;

        switch (dp->pos) {
        case TBL_DATA_NONE:
                return;
        case TBL_DATA_HORIZ:
        case TBL_DATA_NHORIZ:
                tbl_fill_border(tp, BHORIZ, coloff, col->width);
                return;
        case TBL_DATA_NDHORIZ:
        case TBL_DATA_DHORIZ:
                tbl_fill_border(tp, BHORIZ * 2, coloff, col->width);
                return;
        default:
                break;
        }

        switch (cp->pos) {
        case TBL_CELL_LONG:
        case TBL_CELL_CENTRE:
        case TBL_CELL_LEFT:
        case TBL_CELL_RIGHT:
                tbl_literal(tp, dp, col, coloff);
                break;
        case TBL_CELL_NUMBER:
                tbl_number(tp, opts, dp, col, coloff);
                break;
        case TBL_CELL_DOWN:
        case TBL_CELL_SPAN:
                break;
        default:
                abort();
        }
}

/*
 * Print multiple copies of the string cp to advance to
 * len basic units from the left edge of the current column.
 */
static void
tbl_fill_string(struct termp *tp, const char *cp, size_t *coloff, size_t len)
{
        size_t   sz;      /* Width of the string cp in basic units. */
        size_t   target;  /* Distance from the left margin in basic units. */

        if (len == 0)
                return;
        sz = term_strlen(tp, cp);
        target = tp->tcol->offset + len;
        while (*coloff < target) {
                term_word(tp, cp);
                *coloff += sz;
        }
}

/*
 * Print multiple copies of the ASCII character c to advance to
 * len basic units from the left edge of the current column.
 */
static void
tbl_fill_char(struct termp *tp, char c, size_t *coloff, size_t len)
{
        char     cp[2];

        cp[0] = c;
        cp[1] = '\0';
        tbl_fill_string(tp, cp, coloff, len);
}

/*
 * Print multiple copies of the border c to fill len basic units.
 * Used for horizontal lines inside table cells.
 */
static void
tbl_fill_border(struct termp *tp, int c, size_t *coloff, size_t len)
{
        char     buf[12];

        if ((c = borders_locale[c]) > 127) {
                (void)snprintf(buf, sizeof(buf), "\\[u%04x]", c);
                tbl_fill_string(tp, buf, coloff, len);
        } else
                tbl_fill_char(tp, c, coloff, len);
}

/*
 * The same, but bypassing term_flushln().
 * Used for horizontal and vertical lines at the edges of table cells.
 */
static void
tbl_direct_border(struct termp *tp, int c, size_t len)
{
        size_t   sz;      /* Width of the character in basic units. */
        size_t   enw2;    /* Width of half an EN in basic units. */
        size_t   target;  /* Distance from the left margin in basic units. */

        c = borders_locale[c];
        sz = (*tp->getwidth)(tp, c);
        enw2 = (*tp->getwidth)(tp, ' ') / 2;
        target = tp->viscol + len;
        while (tp->viscol + enw2 < target) {
                (*tp->letter)(tp, c);
                tp->viscol += sz;
        }
}

static void
tbl_literal(struct termp *tp, const struct tbl_dat *dp,
                const struct roffcol *col, size_t *coloff)
{
        size_t   width;  /* Of the cell including following spans [BU]. */
        int      ic;     /* Column number of the cell. */
        int      hspans; /* Number of horizontal spans that follow. */

        width = col->width;
        ic = dp->layout->col;
        hspans = dp->hspans;
        while (hspans--) {
                width += term_len(tp, tp->tbl.cols[ic].spacing);
                ic++;
                width += tp->tbl.cols[ic].width;
        }
        tbl_word(tp, dp);
        *coloff += width;
}

static void
tbl_number(struct termp *tp, const struct tbl_opts *opts,
                const struct tbl_dat *dp,
                const struct roffcol *col, size_t *coloff)
{
        const char      *cp, *lastdigit, *lastpoint;

        /* Widths in basic units. */
        size_t           pad;   /* Padding before the number. */
        size_t           totsz; /* Of the number to be printed. */
        size_t           intsz; /* Of the integer part. */

        char             buf[2];

        /*
         * Almost the same code as in tblcalc_number():
         * First find the position of the decimal point.
         */

        assert(dp->string);
        lastdigit = lastpoint = NULL;
        for (cp = dp->string; cp[0] != '\0'; cp++) {
                if (cp[0] == '\\' && cp[1] == '&') {
                        lastdigit = lastpoint = cp;
                        break;
                } else if (cp[0] == opts->decimal &&
                    (isdigit((unsigned char)cp[1]) ||
                     (cp > dp->string && isdigit((unsigned char)cp[-1]))))
                        lastpoint = cp;
                else if (isdigit((unsigned char)cp[0]))
                        lastdigit = cp;
        }

        /* Then measure both widths. */

        pad = 0;
        totsz = term_strlen(tp, dp->string);
        if (lastdigit != NULL) {
                if (lastpoint == NULL)
                        lastpoint = lastdigit + 1;
                intsz = 0;
                buf[1] = '\0';
                for (cp = dp->string; cp < lastpoint; cp++) {
                        buf[0] = cp[0];
                        intsz += term_strlen(tp, buf);
                }

                /*
                 * Pad left to match the decimal position,
                 * but avoid exceeding the total column width.
                 */

                if (col->decimal > intsz && col->width > totsz) {
                        pad = col->decimal - intsz;
                        if (pad + totsz > col->width)
                                pad = col->width - totsz;
                }

        /* If it is not a number, simply center the string. */

        } else if (col->width > totsz)
                pad = (col->width - totsz) / 2;

        tbl_fill_char(tp, ASCII_NBRSP, coloff, pad);
        tbl_word(tp, dp);
        *coloff += col->width;
}

static void
tbl_word(struct termp *tp, const struct tbl_dat *dp)
{
        int              prev_font;

        prev_font = tp->fonti;
        switch (dp->layout->font) {
                case ESCAPE_FONTBI:
                        term_fontpush(tp, TERMFONT_BI);
                        break;
                case ESCAPE_FONTBOLD:
                case ESCAPE_FONTCB:
                        term_fontpush(tp, TERMFONT_BOLD);
                        break;
                case ESCAPE_FONTITALIC:
                case ESCAPE_FONTCI:
                        term_fontpush(tp, TERMFONT_UNDER);
                        break;
                case ESCAPE_FONTROMAN:
                case ESCAPE_FONTCR:
                        break;
                default:
                        abort();
        }

        term_word(tp, dp->string);

        term_fontpopq(tp, prev_font);
}