[mandoc.git] / term.c

/*      $Id: term.c,v 1.192 2011/05/17 11:55:08 kristaps Exp $ */
/*
 * Copyright (c) 2008, 2009, 2010 Kristaps Dzonsons <kristaps@bsd.lv>
 * Copyright (c) 2010, 2011 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 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.
 */
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

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

static  void             adjbuf(struct termp *p, int);
static  void             bufferc(struct termp *, char);
static  void             encode(struct termp *, const char *, size_t);

void
term_free(struct termp *p)
{

        if (p->buf)
                free(p->buf);
        if (p->symtab)
                mchars_free(p->symtab);

        free(p);
}


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

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


void
term_end(struct termp *p)
{

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


struct termp *
term_alloc(enum termenc enc)
{
        struct termp    *p;

        p = mandoc_calloc(1, sizeof(struct termp));
        p->enc = enc;
        return(p);
}


/*
 * Flush a line of text.  A "line" is loosely defined as being something
 * that should be followed by a newline, regardless of whether it's
 * broken apart by newlines getting there.  A line can also be a
 * fragment of a columnar list (`Bl -tag' or `Bl -column'), which does
 * not have a trailing newline.
 *
 * The following flags may be specified:
 *
 *  - TERMP_NOLPAD: when beginning to write the line, don't left-pad the
 *    offset value.  This is useful when doing columnar lists where the
 *    prior column has right-padded.
 *
 *  - TERMP_NOBREAK: this is the most important and is used when making
 *    columns.  In short: don't print a newline and instead pad to the
 *    right margin.  Used in conjunction with TERMP_NOLPAD.
 *
 *  - TERMP_TWOSPACE: when padding, make sure there are at least two
 *    space characters of padding.  Otherwise, rather break the line.
 *
 *  - TERMP_DANGLE: don't newline when TERMP_NOBREAK is specified and
 *    the line is overrun, and don't pad-right if it's underrun.
 *
 *  - TERMP_HANG: like TERMP_DANGLE, but doesn't newline when
 *    overruning, instead save the position and continue at that point
 *    when the next invocation.
 *
 *  In-line line breaking:
 *
 *  If TERMP_NOBREAK is specified and the line overruns the right
 *  margin, it will break and pad-right to the right margin after
 *  writing.  If maxrmargin is violated, it will break and continue
 *  writing from the right-margin, which will lead to the above scenario
 *  upon exit.  Otherwise, the line will break at the right margin.
 */
void
term_flushln(struct termp *p)
{
        int              i;     /* current input position in p->buf */
        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 */
        int              j;     /* temporary loop index for p->buf */
        int              jhy;   /* last hyph before overflow w/r/t j */
        size_t           maxvis; /* output position of visible boundary */
        size_t           mmax; /* used in calculating bp */

        /*
         * 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. 
         */
        assert  (p->rmargin >= p->offset);
        dv     = p->rmargin - p->offset;
        maxvis = (int)dv > p->overstep ? dv - (size_t)p->overstep : 0;
        dv     = p->maxrmargin - p->offset;
        mmax   = (int)dv > p->overstep ? dv - (size_t)p->overstep : 0;

        bp = TERMP_NOBREAK & p->flags ? mmax : maxvis;

        /*
         * Indent the first line of a paragraph.
         */
        vbl = p->flags & TERMP_NOLPAD ? (size_t)0 : p->offset;

        vis = vend = 0;
        i = 0;

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

                        /* Back over the 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])
                                jhy = 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);
                        if (TERMP_NOBREAK & p->flags) {
                                p->viscol = p->rmargin;
                                (*p->advance)(p, p->rmargin);
                                vend += p->rmargin - p->offset;
                        } else {
                                p->viscol = 0;
                                vbl = p->offset;
                        }

                        /* Remove the p->overstep width. */

                        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 (' ' == p->buf[i])
                                        i++;
                                dv = (size_t)(i - j) * (*p->width)(p, ' ');
                                vbl += dv;
                                vend += dv;
                                break;
                        }
                        if (ASCII_NBRSP == p->buf[i]) {
                                vbl += (*p->width)(p, ' ');
                                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;
                        }

                        if (ASCII_HYPH == p->buf[i]) {
                                (*p->letter)(p, '-');
                                p->viscol += (*p->width)(p, '-');
                        } else {
                                (*p->letter)(p, p->buf[i]);
                                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.
         */
        vis -= vbl;

        p->col = 0;
        p->overstep = 0;

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

        if (TERMP_HANG & p->flags) {
                /* We need one blank after the tag. */
                p->overstep = (int)(vis - maxvis + (*p->width)(p, ' '));

                /*
                 * Behave exactly the same way as groff:
                 * If we have overstepped the margin, temporarily move
                 * it to the right and flag the rest of the line to be
                 * shorter.
                 * If we landed right at the margin, be happy.
                 * If we are one step before the margin, temporarily
                 * move it one step LEFT and flag the rest of the line
                 * to be longer.
                 */
                if (p->overstep >= -1) {
                        assert((int)maxvis + p->overstep >= 0);
                        maxvis += (size_t)p->overstep;
                } else
                        p->overstep = 0;

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

        /* Right-pad. */
        if (maxvis > vis +
            ((TERMP_TWOSPACE & p->flags) ? (*p->width)(p, ' ') : 0)) {
                p->viscol += maxvis - vis;
                (*p->advance)(p, maxvis - vis);
                vis += (maxvis - vis);
        } else {        /* ...or newline break. */
                (*p->endline)(p);
                p->viscol = p->rmargin;
                (*p->advance)(p, p->rmargin);
        }
}


/* 
 * 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 (0 == p->col && 0 == p->viscol) {
                p->flags &= ~TERMP_NOLPAD;
                return;
        }
        term_flushln(p);
        p->flags &= ~TERMP_NOLPAD;
}


/*
 * 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->endline)(p);
}

void
term_fontlast(struct termp *p)
{
        enum termfont    f;

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


void
term_fontrepl(struct termp *p, enum termfont f)
{

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


void
term_fontpush(struct termp *p, enum termfont f)
{

        assert(p->fonti + 1 < 10);
        p->fontl = p->fontq[p->fonti];
        p->fontq[++p->fonti] = f;
}


const void *
term_fontq(struct termp *p)
{

        return(&p->fontq[p->fonti]);
}


enum termfont
term_fonttop(struct termp *p)
{

        return(p->fontq[p->fonti]);
}


void
term_fontpopq(struct termp *p, const void *key)
{

        while (p->fonti >= 0 && key != &p->fontq[p->fonti])
                p->fonti--;
        assert(p->fonti >= 0);
}


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      *seq, *cp;
        char             c;
        int              sz;
        size_t           ssz;
        enum mandoc_esc  esc;

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

        if ( ! (p->flags & TERMP_NONOSPACE))
                p->flags &= ~TERMP_NOSPACE;
        else
                p->flags |= TERMP_NOSPACE;

        p->flags &= ~(TERMP_SENTENCE | TERMP_IGNDELIM);

        while ('\0' != *word) {
                if ((ssz = strcspn(word, "\\")) > 0)
                        encode(p, word, ssz);

                word += (int)ssz;
                if ('\\' != *word)
                        continue;

                word++;
                esc = mandoc_escape(&word, &seq, &sz);
                if (ESCAPE_ERROR == esc)
                        break;

                switch (esc) {
                case (ESCAPE_UNICODE):
                        encode(p, "?", 1);
                        break;
                case (ESCAPE_NUMBERED):
                        if ('\0' != (c = mchars_num2char(seq, sz)))
                                encode(p, &c, 1);
                        break;
                case (ESCAPE_PREDEF):
                        cp = mchars_res2str(p->symtab, seq, sz, &ssz);
                        if (NULL != cp)
                                encode(p, cp, ssz);
                        break;
                case (ESCAPE_SPECIAL):
                        cp = mchars_spec2str(p->symtab, seq, sz, &ssz);
                        if (NULL != cp) 
                                encode(p, cp, ssz);
                        else if (1 == ssz)
                                encode(p, seq, sz);
                        break;
                case (ESCAPE_FONTBOLD):
                        term_fontrepl(p, TERMFONT_BOLD);
                        break;
                case (ESCAPE_FONTITALIC):
                        term_fontrepl(p, TERMFONT_UNDER);
                        break;
                case (ESCAPE_FONTROMAN):
                        term_fontrepl(p, TERMFONT_NONE);
                        break;
                case (ESCAPE_FONTPREV):
                        term_fontlast(p);
                        break;
                case (ESCAPE_NOSPACE):
                        if ('\0' == *word)
                                p->flags |= TERMP_NOSPACE;
                        break;
                default:
                        break;
                }
        }
}

static void
adjbuf(struct termp *p, int sz)
{

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

        p->buf = mandoc_realloc
                (p->buf, sizeof(int) * (size_t)p->maxcols);
}

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

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

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

static void
encode(struct termp *p, const char *word, size_t sz)
{
        enum termfont     f;
        int               i, len;

        /* LINTED */
        len = sz;

        /*
         * Encode and buffer a string of characters.  If the current
         * font mode is unset, buffer directly, else encode then buffer
         * character by character.
         */

        if (TERMFONT_NONE == (f = term_fonttop(p))) {
                if (p->col + len >= p->maxcols) 
                        adjbuf(p, p->col + len);
                for (i = 0; i < len; i++)
                        p->buf[p->col++] = word[i];
                return;
        }

        /* Pre-buffer, assuming worst-case. */

        if (p->col + 1 + (len * 3) >= p->maxcols)
                adjbuf(p, p->col + 1 + (len * 3));

        for (i = 0; i < len; i++) {
                if ( ! isgraph((unsigned char)word[i])) {
                        p->buf[p->col++] = word[i];
                        continue;
                }

                if (TERMFONT_UNDER == f)
                        p->buf[p->col++] = '_';
                else
                        p->buf[p->col++] = word[i];

                p->buf[p->col++] = 8;
                p->buf[p->col++] = word[i];
        }
}

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

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


size_t
term_strlen(const struct termp *p, const char *cp)
{
        size_t           sz, rsz, i;
        int              ssz, c;
        const char      *seq, *rhs;
        static const char rej[] = { '\\', ASCII_HYPH, ASCII_NBRSP, '\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;
        while ('\0' != *cp) {
                rsz = strcspn(cp, rej);
                for (i = 0; i < rsz; i++)
                        sz += (*p->width)(p, *cp++);

                c = 0;
                switch (*cp) {
                case ('\\'):
                        cp++;
                        rhs = NULL;
                        switch (mandoc_escape(&cp, &seq, &ssz)) {
                        case (ESCAPE_ERROR):
                                return(sz);
                        case (ESCAPE_UNICODE):
                                c = '?';
                                /* FALLTHROUGH */
                        case (ESCAPE_NUMBERED):
                                if ('\0' != c)
                                        c = mchars_num2char(seq, ssz);
                                if ('\0' != c)
                                        sz += (*p->width)(p, c);
                                break;
                        case (ESCAPE_PREDEF):
                                rhs = mchars_res2str
                                        (p->symtab, seq, ssz, &rsz);
                                break;
                        case (ESCAPE_SPECIAL):
                                rhs = mchars_spec2str
                                        (p->symtab, seq, ssz, &rsz);

                                if (ssz != 1 || rhs)
                                        break;

                                rhs = seq;
                                rsz = ssz;
                                break;
                        default:
                                break;
                        }

                        if (NULL == rhs)
                                break;

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

        return(sz);
}

/* ARGSUSED */
size_t
term_vspan(const struct termp *p, const struct roffsu *su)
{
        double           r;

        switch (su->unit) {
        case (SCALE_CM):
                r = su->scale * 2;
                break;
        case (SCALE_IN):
                r = su->scale * 6;
                break;
        case (SCALE_PC):
                r = su->scale;
                break;
        case (SCALE_PT):
                r = su->scale / 8;
                break;
        case (SCALE_MM):
                r = su->scale / 1000;
                break;
        case (SCALE_VS):
                r = su->scale;
                break;
        default:
                r = su->scale - 1;
                break;
        }

        if (r < 0.0)
                r = 0.0;
        return(/* LINTED */(size_t)
                        r);
}

size_t
term_hspan(const struct termp *p, const struct roffsu *su)
{
        double           v;

        v = ((*p->hspan)(p, su));
        if (v < 0.0)
                v = 0.0;
        return((size_t) /* LINTED */
                        v);
}