cmd/mandoc/term.c

/*  $Id: term.c,v 1.257 2016/04/12 15:30:00 schwarze Exp $ */
/*
 * Copyright (c) 2008, 2009, 2010, 2011 Kristaps Dzonsons <kristaps@bsd.lv>
 * Copyright (c) 2010-2015 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 <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 *p, size_t);
static  void         bufferc(struct termp *, char);
static  void         encode(struct termp *, const char *, size_t);
static  void         encode1(struct termp *, int);


void
term_free(struct termp *p)
{

    free(p->buf);
    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.
 * The following flags may be specified:
 *
 *  - TERMP_NOBREAK: Do not break the output line at the right margin,
 *    but only at the max right margin.  Also, do not break the output
 *    line at the end of the chunk, such that the next call can pad to
 *    the next column.  However, if less than p->trailspace blanks,
 *    which can be 0, 1, or 2, remain to the right margin, the line
 *    will be broken.
 *  - TERMP_BRTRSP: Consider trailing whitespace significant
 *    when deciding whether the chunk fits or not.
 *  - TERMP_BRIND: If the chunk does not fit and the output line has
 *    to be broken, start the next line at the right margin instead
 *    of at the offset.  Used together with TERMP_NOBREAK for the tags
 *    in various kinds of tagged lists.
 *  - TERMP_DANGLE: Do not break the output line at the right margin,
 *    append the next chunk after it even if this one is too long.
 *    To be used together with TERMP_NOBREAK.
 *  - TERMP_HANG: Like TERMP_DANGLE, and also suppress padding before
 *    the next chunk if this column is not full.
 */
void
term_flushln(struct termp *p)
{
    size_t       i;     /* current input position in p->buf */
    int      ntab;  /* number of tabs to prepend */
    size_t       vis;   /* current visual position on output */
    size_t       vbl;   /* number of blanks to prepend to output */
    size_t       vend;  /* end of word visual position on output */
    size_t       bp;    /* visual right border position */
    size_t       dv;    /* temporary for visual pos calculations */
    size_t       j;     /* temporary loop index for p->buf */
    size_t       jhy;   /* last hyph before overflow w/r/t j */
    size_t       maxvis; /* output position of visible boundary */

    /*
     * First, establish the maximum columns of "visible" content.
     * This is usually the difference between the right-margin and
     * an indentation, but can be, for tagged lists or columns, a
     * small set of values.
     *
     * The following unsigned-signed subtractions look strange,
     * but they are actually correct.  If the int p->overstep
     * is negative, it gets sign extended.  Subtracting that
     * very large size_t effectively adds a small number to dv.
     */
    dv = p->rmargin > p->offset ? p->rmargin - p->offset : 0;
    maxvis = (int)dv > p->overstep ? dv - (size_t)p->overstep : 0;

    if (p->flags & TERMP_NOBREAK) {
        dv = p->maxrmargin > p->offset ?
             p->maxrmargin - p->offset : 0;
        bp = (int)dv > p->overstep ?
             dv - (size_t)p->overstep : 0;
    } else
        bp = maxvis;

    /*
     * Calculate the required amount of padding.
     */
    vbl = p->offset + p->overstep > p->viscol ?
          p->offset + p->overstep - p->viscol : 0;

    vis = vend = 0;
    i = 0;

    while (i < p->col) {
        /*
         * Handle literal tab characters: collapse all
         * subsequent tabs into a single huge set of spaces.
         */
        ntab = 0;
        while (i < p->col && '\t' == p->buf[i]) {
            vend = (vis / p->tabwidth + 1) * p->tabwidth;
            vbl += vend - vis;
            vis = vend;
            ntab++;
            i++;
        }

        /*
         * Count up visible word characters.  Control sequences
         * (starting with the CSI) aren't counted.  A space
         * generates a non-printing word, which is valid (the
         * space is printed according to regular spacing rules).
         */

        for (j = i, jhy = 0; j < p->col; j++) {
            if (' ' == p->buf[j] || '\t' == p->buf[j])
                break;

            /* Back over the last printed character. */
            if (8 == p->buf[j]) {
                assert(j);
                vend -= (*p->width)(p, p->buf[j - 1]);
                continue;
            }

            /* Regular word. */
            /* Break at the hyphen point if we overrun. */
            if (vend > vis && vend < bp &&
                (ASCII_HYPH == p->buf[j] ||
                 ASCII_BREAK == p->buf[j]))
                jhy = j;

            /*
             * Hyphenation now decided, put back a real
             * hyphen such that we get the correct width.
             */
            if (ASCII_HYPH == p->buf[j])
                p->buf[j] = '-';

            vend += (*p->width)(p, p->buf[j]);
        }

        /*
         * Find out whether we would exceed the right margin.
         * If so, break to the next line.
         */
        if (vend > bp && 0 == jhy && vis > 0) {
            vend -= vis;
            (*p->endline)(p);
            p->viscol = 0;
            if (TERMP_BRIND & p->flags) {
                vbl = p->rmargin;
                vend += p->rmargin;
                vend -= p->offset;
            } else
                vbl = p->offset;

            /* use pending tabs on the new line */

            if (0 < ntab)
                vbl += ntab * p->tabwidth;

            /*
             * Remove the p->overstep width.
             * Again, if p->overstep is negative,
             * sign extension does the right thing.
             */

            bp += (size_t)p->overstep;
            p->overstep = 0;
        }

        /* Write out the [remaining] word. */
        for ( ; i < p->col; i++) {
            if (vend > bp && jhy > 0 && i > jhy)
                break;
            if ('\t' == p->buf[i])
                break;
            if (' ' == p->buf[i]) {
                j = i;
                while (i < p->col && ' ' == p->buf[i])
                    i++;
                dv = (i - j) * (*p->width)(p, ' ');
                vbl += dv;
                vend += dv;
                break;
            }
            if (ASCII_NBRSP == p->buf[i]) {
                vbl += (*p->width)(p, ' ');
                continue;
            }
            if (ASCII_BREAK == p->buf[i])
                continue;

            /*
             * Now we definitely know there will be
             * printable characters to output,
             * so write preceding white space now.
             */
            if (vbl) {
                (*p->advance)(p, vbl);
                p->viscol += vbl;
                vbl = 0;
            }

            (*p->letter)(p, p->buf[i]);
            if (8 == p->buf[i])
                p->viscol -= (*p->width)(p, p->buf[i-1]);
            else
                p->viscol += (*p->width)(p, p->buf[i]);
        }
        vis = vend;
    }

    /*
     * If there was trailing white space, it was not printed;
     * so reset the cursor position accordingly.
     */
    if (vis > vbl)
        vis -= vbl;
    else
        vis = 0;

    p->col = 0;
    p->overstep = 0;
    p->flags &= ~(TERMP_BACKAFTER | TERMP_BACKBEFORE);

    if ( ! (TERMP_NOBREAK & p->flags)) {
        p->viscol = 0;
        (*p->endline)(p);
        return;
    }

    if (TERMP_HANG & p->flags) {
        p->overstep += (int)(p->offset + vis - p->rmargin +
            p->trailspace * (*p->width)(p, ' '));

        /*
         * If we have overstepped the margin, temporarily move
         * it to the right and flag the rest of the line to be
         * shorter.
         * If there is a request to keep the columns together,
         * allow negative overstep when the column is not full.
         */
        if (p->trailspace && p->overstep < 0)
            p->overstep = 0;
        return;

    } else if (TERMP_DANGLE & p->flags)
        return;

    /* Trailing whitespace is significant in some columns. */
    if (vis && vbl && (TERMP_BRTRSP & p->flags))
        vis += vbl;

    /* If the column was overrun, break the line. */
    if (maxvis < vis + p->trailspace * (*p->width)(p, ' ')) {
        (*p->endline)(p);
        p->viscol = 0;
    }
}

/*
 * 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->col || 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;
    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)
{
    const char   nbrsp[2] = { ASCII_NBRSP, 0 };
    const char  *seq, *cp;
    int      sz, uc;
    size_t       ssz;
    enum mandoc_esc  esc;

    if ( ! (TERMP_NOSPACE & p->flags)) {
        if ( ! (TERMP_KEEP & p->flags)) {
            bufferc(p, ' ');
            if (TERMP_SENTENCE & p->flags)
                bufferc(p, ' ');
        } else
            bufferc(p, ASCII_NBRSP);
    }
    if (TERMP_PREKEEP & p->flags)
        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);
        if (ESCAPE_ERROR == esc)
            continue;

        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_FONTBOLD:
            term_fontrepl(p, TERMFONT_BOLD);
            continue;
        case ESCAPE_FONTITALIC:
            term_fontrepl(p, TERMFONT_UNDER);
            continue;
        case ESCAPE_FONTBI:
            term_fontrepl(p, TERMFONT_BI);
            continue;
        case ESCAPE_FONT:
        case ESCAPE_FONTROMAN:
            term_fontrepl(p, TERMFONT_NONE);
            continue;
        case ESCAPE_FONTPREV:
            term_fontlast(p);
            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_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->col > 2 && p->buf[p->col - 1] == ' ')
                p->col -= 2;
            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 *p, size_t sz)
{

    if (0 == p->maxcols)
        p->maxcols = 1024;
    while (sz >= p->maxcols)
        p->maxcols <<= 2;

    p->buf = mandoc_reallocarray(p->buf, p->maxcols, sizeof(int));
}

static void
bufferc(struct termp *p, char c)
{

    if (p->col + 1 >= p->maxcols)
        adjbuf(p, p->col + 1);

    p->buf[p->col++] = c;
}

/*
 * 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->col + 7 >= p->maxcols)
        adjbuf(p, p->col + 7);

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

    if (p->flags & TERMP_BACKBEFORE) {
        if (p->buf[p->col - 1] == ' ')
            p->col--;
        else
            p->buf[p->col++] = 8;
        p->flags &= ~TERMP_BACKBEFORE;
    }
    if (TERMFONT_UNDER == f || TERMFONT_BI == f) {
        p->buf[p->col++] = '_';
        p->buf[p->col++] = 8;
    }
    if (TERMFONT_BOLD == f || TERMFONT_BI == f) {
        if (ASCII_HYPH == c)
            p->buf[p->col++] = '-';
        else
            p->buf[p->col++] = c;
        p->buf[p->col++] = 8;
    }
    p->buf[p->col++] = c;
    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->col + 2 + (sz * 5) >= p->maxcols)
        adjbuf(p, 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
            p->buf[p->col++] = word[i];
    }
}

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))
            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++;
            esc = mandoc_escape(&cp, &seq, &ssz);
            if (ESCAPE_ERROR == esc)
                continue;

            rhs = NULL;

            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_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 down.
 */
int
term_hspan(const struct termp *p, const struct roffsu *su)
{

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