/* $Id: term.c,v 1.283 2021/08/10 12:55:04 schwarze Exp $ */
/*
 * Copyright (c) 2008, 2009, 2010, 2011 Kristaps Dzonsons <kristaps@bsd.lv>
 * Copyright (c) 2010-2020 Ingo Schwarze <schwarze@openbsd.org>
 *
 * 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 AUTHORS DISCLAIM ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHORS 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 "config.h"

#include <sys/types.h>

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

#include "mandoc.h"
#include "mandoc_aux.h"
#include "out.h"
#include "term.h"
#include "main.h"

static  size_t           cond_width(const struct termp *, int, int *);
static  void             adjbuf(struct termp_col *, size_t);
static  void             bufferc(struct termp *, char);
static  void             encode(struct termp *, const char *, size_t);
static  void             encode1(struct termp *, int);
static  void             endline(struct termp *);
static  void             term_field(struct termp *, size_t, size_t);
static  void             term_fill(struct termp *, size_t *, size_t *,
                                size_t);


void
term_setcol(struct termp *p, size_t maxtcol)
{
        if (maxtcol > p->maxtcol) {
                p->tcols = mandoc_recallocarray(p->tcols,
                    p->maxtcol, maxtcol, sizeof(*p->tcols));
                p->maxtcol = maxtcol;
        }
        p->lasttcol = maxtcol - 1;
        p->tcol = p->tcols;
}

void
term_free(struct termp *p)
{
        for (p->tcol = p->tcols; p->tcol < p->tcols + p->maxtcol; p->tcol++)
                free(p->tcol->buf);
        free(p->tcols);
        free(p->fontq);
        free(p);
}

void
term_begin(struct termp *p, term_margin head,
                term_margin foot, const struct roff_meta *arg)
{

        p->headf = head;
        p->footf = foot;
        p->argf = arg;
        (*p->begin)(p);
}

void
term_end(struct termp *p)
{

        (*p->end)(p);
}

/*
 * Flush a chunk of text.  By default, break the output line each time
 * the right margin is reached, and continue output on the next line
 * at the same offset as the chunk itself.  By default, also break the
 * output line at the end of the chunk.  There are many flags modifying
 * this behaviour, see the comments in the body of the function.
 */
void
term_flushln(struct termp *p)
{
        size_t   vbl;      /* Number of blanks to prepend to the output. */
        size_t   vbr;      /* Actual visual position of the end of field. */
        size_t   vfield;   /* Desired visual field width. */
        size_t   vtarget;  /* Desired visual position of the right margin. */
        size_t   ic;       /* Character position in the input buffer. */
        size_t   nbr;      /* Number of characters to print in this field. */

        /*
         * Normally, start writing at the left margin, but with the
         * NOPAD flag, start writing at the current position instead.
         */

        vbl = (p->flags & TERMP_NOPAD) || p->tcol->offset < p->viscol ?
            0 : p->tcol->offset - p->viscol;
        if (p->minbl && vbl < p->minbl)
                vbl = p->minbl;

        if ((p->flags & TERMP_MULTICOL) == 0)
                p->tcol->col = 0;

        /* Loop over output lines. */

        for (;;) {
                vfield = p->tcol->rmargin > p->viscol + vbl ?
                    p->tcol->rmargin - p->viscol - vbl : 0;

                /*
                 * Normally, break the line at the the right margin
                 * of the field, but with the NOBREAK flag, only
                 * break it at the max right margin of the screen,
                 * and with the BRNEVER flag, never break it at all.
                 */

                vtarget = (p->flags & TERMP_NOBREAK) == 0 ? vfield :
                    p->maxrmargin > p->viscol + vbl ?
                    p->maxrmargin - p->viscol - vbl : 0;

                /*
                 * Figure out how much text will fit in the field.
                 * If there is whitespace only, print nothing.
                 */

                term_fill(p, &nbr, &vbr,
                    p->flags & TERMP_BRNEVER ? SIZE_MAX : vtarget);
                if (nbr == 0)
                        break;

                /*
                 * With the CENTER or RIGHT flag, increase the indentation
                 * to center the text between the left and right margins
                 * or to adjust it to the right margin, respectively.
                 */

                if (vbr < vtarget) {
                        if (p->flags & TERMP_CENTER)
                                vbl += (vtarget - vbr) / 2;
                        else if (p->flags & TERMP_RIGHT)
                                vbl += vtarget - vbr;
                }

                /* Finally, print the field content. */

                term_field(p, vbl, nbr);

                /*
                 * If there is no text left in the field, exit the loop.
                 * If the BRTRSP flag is set, consider trailing
                 * whitespace significant when deciding whether
                 * the field fits or not.
                 */

                for (ic = p->tcol->col; ic < p->tcol->lastcol; ic++) {
                        switch (p->tcol->buf[ic]) {
                        case '\t':
                                if (p->flags & TERMP_BRTRSP)
                                        vbr = term_tab_next(vbr);
                                continue;
                        case ' ':
                                if (p->flags & TERMP_BRTRSP)
                                        vbr += (*p->width)(p, ' ');
                                continue;
                        case '\n':
                        case ASCII_BREAK:
                                continue;
                        default:
                                break;
                        }
                        break;
                }
                if (ic == p->tcol->lastcol)
                        break;

                /*
                 * At the location of an automtic line break, input
                 * space characters are consumed by the line break.
                 */

                while (p->tcol->col < p->tcol->lastcol &&
                    p->tcol->buf[p->tcol->col] == ' ')
                        p->tcol->col++;

                /*
                 * In multi-column mode, leave the rest of the text
                 * in the buffer to be handled by a subsequent
                 * invocation, such that the other columns of the
                 * table can be handled first.
                 * In single-column mode, simply break the line.
                 */

                if (p->flags & TERMP_MULTICOL)
                        return;

                endline(p);
                p->viscol = 0;

                /*
                 * Normally, start the next line at the same indentation
                 * as this one, but with the BRIND flag, start it at the
                 * right margin instead.  This is used together with
                 * NOBREAK for the tags in various kinds of tagged lists.
                 */

                vbl = p->flags & TERMP_BRIND ?
                    p->tcol->rmargin : p->tcol->offset;
        }

        /* Reset output state in preparation for the next field. */

        p->col = p->tcol->col = p->tcol->lastcol = 0;
        p->minbl = p->trailspace;
        p->flags &= ~(TERMP_BACKAFTER | TERMP_BACKBEFORE | TERMP_NOPAD);

        if (p->flags & TERMP_MULTICOL)
                return;

        /*
         * The HANG flag means that the next field
         * always follows on the same line.
         * The NOBREAK flag means that the next field
         * follows on the same line unless the field was overrun.
         * Normally, break the line at the end of each field.
         */

        if ((p->flags & TERMP_HANG) == 0 &&
            ((p->flags & TERMP_NOBREAK) == 0 ||
             vbr + term_len(p, p->trailspace) > vfield))
                endline(p);
}

/*
 * Store the number of input characters to print in this field in *nbr
 * and their total visual width to print in *vbr.
 * If there is only whitespace in the field, both remain zero.
 * The desired visual width of the field is provided by vtarget.
 * If the first word is longer, the field will be overrun.
 */
static void
term_fill(struct termp *p, size_t *nbr, size_t *vbr, size_t vtarget)
{
        size_t   ic;        /* Character position in the input buffer. */
        size_t   vis;       /* Visual position of the current character. */
        size_t   vn;        /* Visual position of the next character. */
        int      breakline; /* Break at the end of this word. */
        int      graph;     /* Last character was non-blank. */

        *nbr = *vbr = vis = 0;
        breakline = graph = 0;
        for (ic = p->tcol->col; ic < p->tcol->lastcol; ic++) {
                switch (p->tcol->buf[ic]) {
                case '\b':  /* Escape \o (overstrike) or backspace markup. */
                        assert(ic > 0);
                        vis -= (*p->width)(p, p->tcol->buf[ic - 1]);
                        continue;

                case '\t':  /* Normal ASCII whitespace. */
                case ' ':
                case ASCII_BREAK:  /* Escape \: (breakpoint). */
                        switch (p->tcol->buf[ic]) {
                        case '\t':
                                vn = term_tab_next(vis);
                                break;
                        case ' ':
                                vn = vis + (*p->width)(p, ' ');
                                break;
                        case ASCII_BREAK:
                                vn = vis;
                                break;
                        default:
                                abort();
                        }
                        /* Can break at the end of a word. */
                        if (breakline || vn > vtarget)
                                break;
                        if (graph) {
                                *nbr = ic;
                                *vbr = vis;
                                graph = 0;
                        }
                        vis = vn;
                        continue;

                case '\n':  /* Escape \p (break at the end of the word). */
                        breakline = 1;
                        continue;

                case ASCII_HYPH:  /* Breakable hyphen. */
                        graph = 1;
                        /*
                         * We are about to decide whether to break the
                         * line or not, so we no longer need this hyphen
                         * to be marked as breakable.  Put back a real
                         * hyphen such that we get the correct width.
                         */
                        p->tcol->buf[ic] = '-';
                        vis += (*p->width)(p, '-');
                        if (vis > vtarget) {
                                ic++;
                                break;
                        }
                        *nbr = ic + 1;
                        *vbr = vis;
                        continue;

                case ASCII_NBRSP:  /* Non-breakable space. */
                        p->tcol->buf[ic] = ' ';
                        /* FALLTHROUGH */
                default:  /* Printable character. */
                        graph = 1;
                        vis += (*p->width)(p, p->tcol->buf[ic]);
                        if (vis > vtarget && *nbr > 0)
                                return;
                        continue;
                }
                break;
        }

        /*
         * If the last word extends to the end of the field without any
         * trailing whitespace, the loop could not check yet whether it
         * can remain on this line.  So do the check now.
         */

        if (graph && (vis <= vtarget || *nbr == 0)) {
                *nbr = ic;
                *vbr = vis;
        }
}

/*
 * Print the contents of one field
 * with an indentation of        vbl      visual columns,
 * and an input string length of nbr      characters.
 */
static void
term_field(struct termp *p, size_t vbl, size_t nbr)
{
        size_t   ic;    /* Character position in the input buffer. */
        size_t   vis;   /* Visual position of the current character. */
        size_t   dv;    /* Visual width of the current character. */
        size_t   vn;    /* Visual position of the next character. */

        vis = 0;
        for (ic = p->tcol->col; ic < nbr; ic++) {

                /*
                 * To avoid the printing of trailing whitespace,
                 * do not print whitespace right away, only count it.
                 */

                switch (p->tcol->buf[ic]) {
                case '\n':
                case ASCII_BREAK:
                        continue;
                case '\t':
                        vn = term_tab_next(vis);
                        vbl += vn - vis;
                        vis = vn;
                        continue;
                case ' ':
                case ASCII_NBRSP:
                        dv = (*p->width)(p, ' ');
                        vbl += dv;
                        vis += dv;
                        continue;
                default:
                        break;
                }

                /*
                 * We found a non-blank character to print,
                 * so write preceding white space now.
                 */

                if (vbl > 0) {
                        (*p->advance)(p, vbl);
                        p->viscol += vbl;
                        vbl = 0;
                }

                /* Print the character and adjust the visual position. */

                (*p->letter)(p, p->tcol->buf[ic]);
                if (p->tcol->buf[ic] == '\b') {
                        dv = (*p->width)(p, p->tcol->buf[ic - 1]);
                        p->viscol -= dv;
                        vis -= dv;
                } else {
                        dv = (*p->width)(p, p->tcol->buf[ic]);
                        p->viscol += dv;
                        vis += dv;
                }
        }
        p->tcol->col = nbr;
}

static void
endline(struct termp *p)
{
        if ((p->flags & (TERMP_NEWMC | TERMP_ENDMC)) == TERMP_ENDMC) {
                p->mc = NULL;
                p->flags &= ~TERMP_ENDMC;
        }
        if (p->mc != NULL) {
                if (p->viscol && p->maxrmargin >= p->viscol)
                        (*p->advance)(p, p->maxrmargin - p->viscol + 1);
                p->flags |= TERMP_NOBUF | TERMP_NOSPACE;
                term_word(p, p->mc);
                p->flags &= ~(TERMP_NOBUF | TERMP_NEWMC);
        }
        p->viscol = 0;
        p->minbl = 0;
        (*p->endline)(p);
}

/*
 * A newline only breaks an existing line; it won't assert vertical
 * space.  All data in the output buffer is flushed prior to the newline
 * assertion.
 */
void
term_newln(struct termp *p)
{

        p->flags |= TERMP_NOSPACE;
        if (p->tcol->lastcol || p->viscol)
                term_flushln(p);
}

/*
 * Asserts a vertical space (a full, empty line-break between lines).
 * Note that if used twice, this will cause two blank spaces and so on.
 * All data in the output buffer is flushed prior to the newline
 * assertion.
 */
void
term_vspace(struct termp *p)
{

        term_newln(p);
        p->viscol = 0;
        p->minbl = 0;
        if (0 < p->skipvsp)
                p->skipvsp--;
        else
                (*p->endline)(p);
}

/* Swap current and previous font; for \fP and .ft P */
void
term_fontlast(struct termp *p)
{
        enum termfont    f;

        f = p->fontl;
        p->fontl = p->fontq[p->fonti];
        p->fontq[p->fonti] = f;
}

/* Set font, save current, discard previous; for \f, .ft, .B etc. */
void
term_fontrepl(struct termp *p, enum termfont f)
{

        p->fontl = p->fontq[p->fonti];
        p->fontq[p->fonti] = f;
}

/* Set font, save previous. */
void
term_fontpush(struct termp *p, enum termfont f)
{

        p->fontl = p->fontq[p->fonti];
        if (++p->fonti == p->fontsz) {
                p->fontsz += 8;
                p->fontq = mandoc_reallocarray(p->fontq,
                    p->fontsz, sizeof(*p->fontq));
        }
        p->fontq[p->fonti] = f;
}

/* Flush to make the saved pointer current again. */
void
term_fontpopq(struct termp *p, int i)
{

        assert(i >= 0);
        if (p->fonti > i)
                p->fonti = i;
}

/* Pop one font off the stack. */
void
term_fontpop(struct termp *p)
{

        assert(p->fonti);
        p->fonti--;
}

/*
 * Handle pwords, partial words, which may be either a single word or a
 * phrase that cannot be broken down (such as a literal string).  This
 * handles word styling.
 */
void
term_word(struct termp *p, const char *word)
{
        struct roffsu    su;
        const char       nbrsp[2] = { ASCII_NBRSP, 0 };
        const char      *seq, *cp;
        int              sz, uc;
        size_t           csz, lsz, ssz;
        enum mandoc_esc  esc;

        if ((p->flags & TERMP_NOBUF) == 0) {
                if ((p->flags & TERMP_NOSPACE) == 0) {
                        if ((p->flags & TERMP_KEEP) == 0) {
                                bufferc(p, ' ');
                                if (p->flags & TERMP_SENTENCE)
                                        bufferc(p, ' ');
                        } else
                                bufferc(p, ASCII_NBRSP);
                }
                if (p->flags & TERMP_PREKEEP)
                        p->flags |= TERMP_KEEP;
                if (p->flags & TERMP_NONOSPACE)
                        p->flags |= TERMP_NOSPACE;
                else
                        p->flags &= ~TERMP_NOSPACE;
                p->flags &= ~(TERMP_SENTENCE | TERMP_NONEWLINE);
                p->skipvsp = 0;
        }

        while ('\0' != *word) {
                if ('\\' != *word) {
                        if (TERMP_NBRWORD & p->flags) {
                                if (' ' == *word) {
                                        encode(p, nbrsp, 1);
                                        word++;
                                        continue;
                                }
                                ssz = strcspn(word, "\\ ");
                        } else
                                ssz = strcspn(word, "\\");
                        encode(p, word, ssz);
                        word += (int)ssz;
                        continue;
                }

                word++;
                esc = mandoc_escape(&word, &seq, &sz);
                switch (esc) {
                case ESCAPE_UNICODE:
                        uc = mchars_num2uc(seq + 1, sz - 1);
                        break;
                case ESCAPE_NUMBERED:
                        uc = mchars_num2char(seq, sz);
                        if (uc < 0)
                                continue;
                        break;
                case ESCAPE_SPECIAL:
                        if (p->enc == TERMENC_ASCII) {
                                cp = mchars_spec2str(seq, sz, &ssz);
                                if (cp != NULL)
                                        encode(p, cp, ssz);
                        } else {
                                uc = mchars_spec2cp(seq, sz);
                                if (uc > 0)
                                        encode1(p, uc);
                        }
                        continue;
                case ESCAPE_UNDEF:
                        uc = *seq;
                        break;
                case ESCAPE_FONTBOLD:
                case ESCAPE_FONTCB:
                        term_fontrepl(p, TERMFONT_BOLD);
                        continue;
                case ESCAPE_FONTITALIC:
                case ESCAPE_FONTCI:
                        term_fontrepl(p, TERMFONT_UNDER);
                        continue;
                case ESCAPE_FONTBI:
                        term_fontrepl(p, TERMFONT_BI);
                        continue;
                case ESCAPE_FONT:
                case ESCAPE_FONTCR:
                case ESCAPE_FONTROMAN:
                        term_fontrepl(p, TERMFONT_NONE);
                        continue;
                case ESCAPE_FONTPREV:
                        term_fontlast(p);
                        continue;
                case ESCAPE_BREAK:
                        bufferc(p, '\n');
                        continue;
                case ESCAPE_NOSPACE:
                        if (p->flags & TERMP_BACKAFTER)
                                p->flags &= ~TERMP_BACKAFTER;
                        else if (*word == '\0')
                                p->flags |= (TERMP_NOSPACE | TERMP_NONEWLINE);
                        continue;
                case ESCAPE_DEVICE:
                        if (p->type == TERMTYPE_PDF)
                                encode(p, "pdf", 3);
                        else if (p->type == TERMTYPE_PS)
                                encode(p, "ps", 2);
                        else if (p->enc == TERMENC_ASCII)
                                encode(p, "ascii", 5);
                        else
                                encode(p, "utf8", 4);
                        continue;
                case ESCAPE_HORIZ:
                        if (*seq == '|') {
                                seq++;
                                uc = -p->col;
                        } else
                                uc = 0;
                        if (a2roffsu(seq, &su, SCALE_EM) == NULL)
                                continue;
                        uc += term_hen(p, &su);
                        if (uc > 0)
                                while (uc-- > 0)
                                        bufferc(p, ASCII_NBRSP);
                        else if (p->col > (size_t)(-uc))
                                p->col += uc;
                        else {
                                uc += p->col;
                                p->col = 0;
                                if (p->tcol->offset > (size_t)(-uc)) {
                                        p->ti += uc;
                                        p->tcol->offset += uc;
                                } else {
                                        p->ti -= p->tcol->offset;
                                        p->tcol->offset = 0;
                                }
                        }
                        continue;
                case ESCAPE_HLINE:
                        if ((cp = a2roffsu(seq, &su, SCALE_EM)) == NULL)
                                continue;
                        uc = term_hen(p, &su);
                        if (uc <= 0) {
                                if (p->tcol->rmargin <= p->tcol->offset)
                                        continue;
                                lsz = p->tcol->rmargin - p->tcol->offset;
                        } else
                                lsz = uc;
                        if (*cp == seq[-1])
                                uc = -1;
                        else if (*cp == '\\') {
                                seq = cp + 1;
                                esc = mandoc_escape(&seq, &cp, &sz);
                                switch (esc) {
                                case ESCAPE_UNICODE:
                                        uc = mchars_num2uc(cp + 1, sz - 1);
                                        break;
                                case ESCAPE_NUMBERED:
                                        uc = mchars_num2char(cp, sz);
                                        break;
                                case ESCAPE_SPECIAL:
                                        uc = mchars_spec2cp(cp, sz);
                                        break;
                                case ESCAPE_UNDEF:
                                        uc = *seq;
                                        break;
                                default:
                                        uc = -1;
                                        break;
                                }
                        } else
                                uc = *cp;
                        if (uc < 0x20 || (uc > 0x7E && uc < 0xA0))
                                uc = '_';
                        if (p->enc == TERMENC_ASCII) {
                                cp = ascii_uc2str(uc);
                                csz = term_strlen(p, cp);
                                ssz = strlen(cp);
                        } else
                                csz = (*p->width)(p, uc);
                        while (lsz >= csz) {
                                if (p->enc == TERMENC_ASCII)
                                        encode(p, cp, ssz);
                                else
                                        encode1(p, uc);
                                lsz -= csz;
                        }
                        continue;
                case ESCAPE_SKIPCHAR:
                        p->flags |= TERMP_BACKAFTER;
                        continue;
                case ESCAPE_OVERSTRIKE:
                        cp = seq + sz;
                        while (seq < cp) {
                                if (*seq == '\\') {
                                        mandoc_escape(&seq, NULL, NULL);
                                        continue;
                                }
                                encode1(p, *seq++);
                                if (seq < cp) {
                                        if (p->flags & TERMP_BACKBEFORE)
                                                p->flags |= TERMP_BACKAFTER;
                                        else
                                                p->flags |= TERMP_BACKBEFORE;
                                }
                        }
                        /* Trim trailing backspace/blank pair. */
                        if (p->tcol->lastcol > 2 &&
                            (p->tcol->buf[p->tcol->lastcol - 1] == ' ' ||
                             p->tcol->buf[p->tcol->lastcol - 1] == '\t'))
                                p->tcol->lastcol -= 2;
                        if (p->col > p->tcol->lastcol)
                                p->col = p->tcol->lastcol;
                        continue;
                default:
                        continue;
                }

                /*
                 * Common handling for Unicode and numbered
                 * character escape sequences.
                 */

                if (p->enc == TERMENC_ASCII) {
                        cp = ascii_uc2str(uc);
                        encode(p, cp, strlen(cp));
                } else {
                        if ((uc < 0x20 && uc != 0x09) ||
                            (uc > 0x7E && uc < 0xA0))
                                uc = 0xFFFD;
                        encode1(p, uc);
                }
        }
        p->flags &= ~TERMP_NBRWORD;
}

static void
adjbuf(struct termp_col *c, size_t sz)
{
        if (c->maxcols == 0)
                c->maxcols = 1024;
        while (c->maxcols <= sz)
                c->maxcols <<= 2;
        c->buf = mandoc_reallocarray(c->buf, c->maxcols, sizeof(*c->buf));
}

static void
bufferc(struct termp *p, char c)
{
        if (p->flags & TERMP_NOBUF) {
                (*p->letter)(p, c);
                return;
        }
        if (p->col + 1 >= p->tcol->maxcols)
                adjbuf(p->tcol, p->col + 1);
        if (p->tcol->lastcol <= p->col || (c != ' ' && c != ASCII_NBRSP))
                p->tcol->buf[p->col] = c;
        if (p->tcol->lastcol < ++p->col)
                p->tcol->lastcol = p->col;
}

/*
 * See encode().
 * Do this for a single (probably unicode) value.
 * Does not check for non-decorated glyphs.
 */
static void
encode1(struct termp *p, int c)
{
        enum termfont     f;

        if (p->flags & TERMP_NOBUF) {
                (*p->letter)(p, c);
                return;
        }

        if (p->col + 7 >= p->tcol->maxcols)
                adjbuf(p->tcol, p->col + 7);

        f = (c == ASCII_HYPH || c > 127 || isgraph(c)) ?
            p->fontq[p->fonti] : TERMFONT_NONE;

        if (p->flags & TERMP_BACKBEFORE) {
                if (p->tcol->buf[p->col - 1] == ' ' ||
                    p->tcol->buf[p->col - 1] == '\t')
                        p->col--;
                else
                        p->tcol->buf[p->col++] = '\b';
                p->flags &= ~TERMP_BACKBEFORE;
        }
        if (f == TERMFONT_UNDER || f == TERMFONT_BI) {
                p->tcol->buf[p->col++] = '_';
                p->tcol->buf[p->col++] = '\b';
        }
        if (f == TERMFONT_BOLD || f == TERMFONT_BI) {
                if (c == ASCII_HYPH)
                        p->tcol->buf[p->col++] = '-';
                else
                        p->tcol->buf[p->col++] = c;
                p->tcol->buf[p->col++] = '\b';
        }
        if (p->tcol->lastcol <= p->col || (c != ' ' && c != ASCII_NBRSP))
                p->tcol->buf[p->col] = c;
        if (p->tcol->lastcol < ++p->col)
                p->tcol->lastcol = p->col;
        if (p->flags & TERMP_BACKAFTER) {
                p->flags |= TERMP_BACKBEFORE;
                p->flags &= ~TERMP_BACKAFTER;
        }
}

static void
encode(struct termp *p, const char *word, size_t sz)
{
        size_t            i;

        if (p->flags & TERMP_NOBUF) {
                for (i = 0; i < sz; i++)
                        (*p->letter)(p, word[i]);
                return;
        }

        if (p->col + 2 + (sz * 5) >= p->tcol->maxcols)
                adjbuf(p->tcol, p->col + 2 + (sz * 5));

        for (i = 0; i < sz; i++) {
                if (ASCII_HYPH == word[i] ||
                    isgraph((unsigned char)word[i]))
                        encode1(p, word[i]);
                else {
                        if (p->tcol->lastcol <= p->col ||
                            (word[i] != ' ' && word[i] != ASCII_NBRSP))
                                p->tcol->buf[p->col] = word[i];
                        p->col++;

                        /*
                         * Postpone the effect of \z while handling
                         * an overstrike sequence from ascii_uc2str().
                         */

                        if (word[i] == '\b' &&
                            (p->flags & TERMP_BACKBEFORE)) {
                                p->flags &= ~TERMP_BACKBEFORE;
                                p->flags |= TERMP_BACKAFTER;
                        }
                }
        }
        if (p->tcol->lastcol < p->col)
                p->tcol->lastcol = p->col;
}

void
term_setwidth(struct termp *p, const char *wstr)
{
        struct roffsu    su;
        int              iop, width;

        iop = 0;
        width = 0;
        if (NULL != wstr) {
                switch (*wstr) {
                case '+':
                        iop = 1;
                        wstr++;
                        break;
                case '-':
                        iop = -1;
                        wstr++;
                        break;
                default:
                        break;
                }
                if (a2roffsu(wstr, &su, SCALE_MAX) != NULL)
                        width = term_hspan(p, &su);
                else
                        iop = 0;
        }
        (*p->setwidth)(p, iop, width);
}

size_t
term_len(const struct termp *p, size_t sz)
{

        return (*p->width)(p, ' ') * sz;
}

static size_t
cond_width(const struct termp *p, int c, int *skip)
{

        if (*skip) {
                (*skip) = 0;
                return 0;
        } else
                return (*p->width)(p, c);
}

size_t
term_strlen(const struct termp *p, const char *cp)
{
        size_t           sz, rsz, i;
        int              ssz, skip, uc;
        const char      *seq, *rhs;
        enum mandoc_esc  esc;
        static const char rej[] = { '\\', ASCII_NBRSP, ASCII_HYPH,
                        ASCII_BREAK, '\0' };

        /*
         * Account for escaped sequences within string length
         * calculations.  This follows the logic in term_word() as we
         * must calculate the width of produced strings.
         */

        sz = 0;
        skip = 0;
        while ('\0' != *cp) {
                rsz = strcspn(cp, rej);
                for (i = 0; i < rsz; i++)
                        sz += cond_width(p, *cp++, &skip);

                switch (*cp) {
                case '\\':
                        cp++;
                        rhs = NULL;
                        esc = mandoc_escape(&cp, &seq, &ssz);
                        switch (esc) {
                        case ESCAPE_UNICODE:
                                uc = mchars_num2uc(seq + 1, ssz - 1);
                                break;
                        case ESCAPE_NUMBERED:
                                uc = mchars_num2char(seq, ssz);
                                if (uc < 0)
                                        continue;
                                break;
                        case ESCAPE_SPECIAL:
                                if (p->enc == TERMENC_ASCII) {
                                        rhs = mchars_spec2str(seq, ssz, &rsz);
                                        if (rhs != NULL)
                                                break;
                                } else {
                                        uc = mchars_spec2cp(seq, ssz);
                                        if (uc > 0)
                                                sz += cond_width(p, uc, &skip);
                                }
                                continue;
                        case ESCAPE_UNDEF:
                                uc = *seq;
                                break;
                        case ESCAPE_DEVICE:
                                if (p->type == TERMTYPE_PDF) {
                                        rhs = "pdf";
                                        rsz = 3;
                                } else if (p->type == TERMTYPE_PS) {
                                        rhs = "ps";
                                        rsz = 2;
                                } else if (p->enc == TERMENC_ASCII) {
                                        rhs = "ascii";
                                        rsz = 5;
                                } else {
                                        rhs = "utf8";
                                        rsz = 4;
                                }
                                break;
                        case ESCAPE_SKIPCHAR:
                                skip = 1;
                                continue;
                        case ESCAPE_OVERSTRIKE:
                                rsz = 0;
                                rhs = seq + ssz;
                                while (seq < rhs) {
                                        if (*seq == '\\') {
                                                mandoc_escape(&seq, NULL, NULL);
                                                continue;
                                        }
                                        i = (*p->width)(p, *seq++);
                                        if (rsz < i)
                                                rsz = i;
                                }
                                sz += rsz;
                                continue;
                        default:
                                continue;
                        }

                        /*
                         * Common handling for Unicode and numbered
                         * character escape sequences.
                         */

                        if (rhs == NULL) {
                                if (p->enc == TERMENC_ASCII) {
                                        rhs = ascii_uc2str(uc);
                                        rsz = strlen(rhs);
                                } else {
                                        if ((uc < 0x20 && uc != 0x09) ||
                                            (uc > 0x7E && uc < 0xA0))
                                                uc = 0xFFFD;
                                        sz += cond_width(p, uc, &skip);
                                        continue;
                                }
                        }

                        if (skip) {
                                skip = 0;
                                break;
                        }

                        /*
                         * Common handling for all escape sequences
                         * printing more than one character.
                         */

                        for (i = 0; i < rsz; i++)
                                sz += (*p->width)(p, *rhs++);
                        break;
                case ASCII_NBRSP:
                        sz += cond_width(p, ' ', &skip);
                        cp++;
                        break;
                case ASCII_HYPH:
                        sz += cond_width(p, '-', &skip);
                        cp++;
                        break;
                default:
                        break;
                }
        }

        return sz;
}

int
term_vspan(const struct termp *p, const struct roffsu *su)
{
        double           r;
        int              ri;

        switch (su->unit) {
        case SCALE_BU:
                r = su->scale / 40.0;
                break;
        case SCALE_CM:
                r = su->scale * 6.0 / 2.54;
                break;
        case SCALE_FS:
                r = su->scale * 65536.0 / 40.0;
                break;
        case SCALE_IN:
                r = su->scale * 6.0;
                break;
        case SCALE_MM:
                r = su->scale * 0.006;
                break;
        case SCALE_PC:
                r = su->scale;
                break;
        case SCALE_PT:
                r = su->scale / 12.0;
                break;
        case SCALE_EN:
        case SCALE_EM:
                r = su->scale * 0.6;
                break;
        case SCALE_VS:
                r = su->scale;
                break;
        default:
                abort();
        }
        ri = r > 0.0 ? r + 0.4995 : r - 0.4995;
        return ri < 66 ? ri : 1;
}

/*
 * Convert a scaling width to basic units, rounding towards 0.
 */
int
term_hspan(const struct termp *p, const struct roffsu *su)
{

        return (*p->hspan)(p, su);
}

/*
 * Convert a scaling width to basic units, rounding to closest.
 */
int
term_hen(const struct termp *p, const struct roffsu *su)
{
        int bu;

        if ((bu = (*p->hspan)(p, su)) >= 0)
                return (bu + 11) / 24;
        else
                return -((-bu + 11) / 24);
}