libc/xcurses/m_cc.c

	m_cc.c revision 7c478bd95313f5f23a4c958a745db2134aa03244
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#pragma ident   "%Z%%M% %I% %E% SMI"

/* LINTLIBRARY */

/*
 * m_cc.c
 *
 * XCurses Library
 *
 * Copyright 1990, 1995 by Mortice Kern Systems Inc.  All rights reserved.
 *
 */

#if M_RCSID
#ifndef lint
static char rcsID[] =
"$Header: /team/ps/sun_xcurses/archive/local_changes/xcurses/src/lib/"
"libxcurses/src/libc/xcurses/rcs/m_cc.c 1.40 1998/06/12 12:45:39 "
"cbates Exp $";
#endif
#endif

#include <private.h>
#include <limits.h>
#include <m_wio.h>
#include <string.h>

typedef struct {
    int max;
    int used;
    char    *mbs;
} t_string;

static int
write_string(int byte, t_string *sp)
{
    if (sp->max <= sp->used)
        return (EOF);

    sp->mbs[sp->used++] = (char)byte;

    return (byte);
}

/*
 * Convert a wint_t string into a multibyte string.
 *
 * The conversion stops at the end of string or the first WEOF.
 * Return the number of bytes successfully placed into mbs.
 */
int
wistombs(char *mbs, const wint_t *wis, int n)
{
    int last;
    t_string string = { 0 };
    t_wide_io convert = { 0 };

    string.max = n;
    string.mbs = mbs;
    convert.object = (void *) &string;
    convert.put = (int (*)(int, void *)) write_string;

    for (; ; ++wis) {
        /* In case of error, rewind string to the last character. */
        last = string.used;

        if (m_wio_put(*wis, &convert) < 0) {
            string.used = last;
            break;
        }

        /*
         * Test for end of string AFTER trying to copy into the
         * buffer, because m_wio_put() has to handle state changes
         * back to the initial state on '\0' or WEOF.
         */
        if (*wis == '\0' || *wis == WEOF)
            break;
    }

    /*
     * m_wio_put() does not write '\0', because the "stream"
     * object is considered to be in "text" mode, which in the
     * case of file I/O produces undefined results for systems
     * using locking-shift character sets.
     */
    string.mbs[string.used] = '\0';

    return (string.used);
}

/*
 * Convert a wint_t string (filled in by wgetn_wstr()) to a wchar_t string.
 * The conversion stops at the end of string or the first WEOF.  Return the
 * number of successfully copied characters.
 *
 * This routinue should be used when sizeof (wchar_t) < sizeof (wint_t).
 */
int
wistowcs(wchar_t *wcs, const wint_t *wis, int n)
{
    wchar_t *start;

    if (n < 0)
        n = INT_MAX;

    for (start = wcs; *wis != '\0' && 0 < n; ++wis, ++wcs, --n) {
        if (*wis == WEOF)
            break;
        *wcs = (wchar_t)*wis;
    }
    *wcs = '\0';

    /* (wcs - start) should be enough small to fit in "int" */
    return ((int)(wcs - start));
}

void
__m_touch_locs(WINDOW *w, int row, int firstCol, int lastCol)
{
    if (w) {
        if (firstCol < w->_first[row])
            w->_first[row] = (short)firstCol;
        if (lastCol > w->_last[row])
            w->_last[row] = (short)lastCol;
    }
}

/*
 * Convert a chtype to a cchar_t.
 */
int
__m_chtype_cc(chtype ch, cchar_t *cc)
{
    char    mb;

    cc->_f = 1;
    cc->_n = 1;
    mb = (char)(ch & A_CHARTEXT);

    cc->_co = (short)PAIR_NUMBER((int)ch);
    cc->_at = (attr_t)((ch & (A_ATTRIBUTES & ~A_COLOR)) >> 16);

    if (mb == 0)
        cc->_wc[0] = cc->_wc[1] = 0;
    else if (mbtowc(cc->_wc, &mb, 1) < 0) {
        return (ERR);
    }
    return (OK);
}

/*
 * Return a complex character as a chtype.
 */
chtype
__m_cc_chtype(const cchar_t *cc)
{
    chtype  ch;
    unsigned char   mb[MB_LEN_MAX];

    /* Is it a single-byte character? */
    if (cc->_n != 1 || wctomb((char *)mb, cc->_wc[0]) != 1)
        return ((chtype) ERR);

    ch = ((chtype) cc->_at << 16) & ~A_COLOR;
    ch |= COLOR_PAIR(cc->_co) | mb[0];

    return (ch);
}

/*
 * Convert a complex character's "character" into a multibyte string.
 * The attribute and colour are ignored.
 *
 * If 0 < n, set a new multibyte string and convert the first character,
 * returning either -1 on error or the number of bytes used to convert the
 * character.
 *
 * If n == 0, continue appending to the current multibyte string and return
 * a value as for 0 < n case.
 *
 * If n < 0, return the accumulated byte length of the current multibyte
 * string and do nothing else.
 *
 * When converting a character, a null cchar_t pointer will force the initial
 * shift state and append a '\0' to the multibyte string.  The return value
 * will instead by the number of bytes used to shift to the initial state,
 * and exclude the '\0'.
 */
int
__m_cc_mbs(const cchar_t *cc, char *mbs, int n)
{
    int i, bytes, count, last;
    static t_string string = { 0 };
    static t_wide_io    convert = { 0 };

    if (n < 0) {
        /* Return total number of bytes written to multibyte string. */
        return (string.used);
    } else if (0 < n) {
        /* Start a new conversion. */
        string.max = n;
        string.used = 0;
        string.mbs = mbs;

        convert._next = convert._size = 0;
        convert.object = (void *) &string;
        convert.put = (int (*)(int, void *)) write_string;
    } /* else n == 0, continue appending to previous mbs. */

    /* In case of error, rewind string to the last character. */
    last = string.used;

    if (cc == NULL) {
        /* Force initial shift state. */
        if ((count = m_wio_put('\0', &convert)) < 0) {
            string.used = last;
            return (-1);
        }

        if (string.used < string.max)
            string.mbs[string.used++] = '\0';
    } else {
        for (count = i = 0; i < cc->_n; ++i, count += bytes)
            if ((bytes = m_wio_put(cc->_wc[i], &convert)) < 0) {
                string.used = last;
                return (-1);
            }
    }

    return (count);
}

/*
 * Convert a stty character into a wchar_t.
 */
int
__m_tty_wc(int index, wchar_t *wcp)
{
    char    mb;
    int code;

    /*
     * Refer to _shell instead of _prog, since _shell will
     * correctly reflect the user's prefered settings, whereas
     * _prog may not have been initialised if both input and
     * output have been redirected.
     */
    mb = (char)PTERMIOS(_shell)->c_cc[index];
    if (mb)
        code = mbtowc(wcp, &mb, 1) < 0 ? ERR : OK;
    else
        code = ERR;

    return (code);
}

/*
 * Build a cchar_t from the leading spacing and non-spacing characters
 * in the multibyte character string.  Only one spacing character is copied
 * from the multibyte character string.
 *
 * Return the number of characters copied from the string, or -1 on error.
 */
int
__m_mbs_cc(const char *mbs, attr_t at, short co, cchar_t *cc)
{
    wchar_t wc;
    const char  *start;
    int i, nbytes, width, have_one;

    for (start = mbs, have_one = i = 0; *mbs != '\0'; mbs += nbytes, ++i) {
        if (sizeof (cc->_wc) <= i)
            /* Too many characters. */
            return (-1);

        if ((nbytes = mbtowc(&wc, mbs, UINT_MAX)) < 0)
            /* Invalid multibyte sequence. */
            return (-1);

        if (nbytes == 0)
            /* Remainder of string evaluates to the null byte. */
            break;

        if (iscntrl(*mbs))
            /* Treat control codes like a spacing character. */
            width = 1;
        else
            width = wcwidth(wc);

        /* Do we have a spacing character? */
        if (0 < width) {
            if (have_one)
                break;
            have_one = 1;
        }

        cc->_wc[i] = wc;
    }

    cc->_f = 1;
    cc->_n = (short)i;
    cc->_co = co;
    cc->_at = at;

    (void) __m_cc_sort(cc);

    /* (mbs - start) should be enough small to fit in "int" */
    return ((int)(mbs - start));
}

/*
 * Build a cchar_t from the leading spacing and non-spacing characters
 * in the wide character string.  Only one spacinig character is copied
 * from the wide character string.
 *
 * Return the number of characters copied from the string, or -1 on error.
 */
int
__m_wcs_cc(const wchar_t *wcs, attr_t at, short co, cchar_t *cc)
{
    short   i;
    const wchar_t   *start;

    for (start = wcs, i = 0; *wcs != '\0'; ++wcs, ++i) {
        if (sizeof (cc->_wc) <= i) {
            /* Too many characters. */
            return (-1);
        }

        if (wcwidth(*wcs) > 0) {
            if (i != 0)
                break;
        } else if ((*wcs == L'\n') || (*wcs == L'\t') ||
            (*wcs == L'\b') || (*wcs == L'\r')) {
            if (i != 0)
                break;
            cc->_wc[i++] = *wcs++;
            break;
        }

        cc->_wc[i] = *wcs;
    }

    cc->_f = 1;
    cc->_n = i;
    cc->_co = co;
    cc->_at = at;

    /* (wcs - start) should be enough small to fit in "int" */
    return ((int)(wcs - start));
}

/*
 * Convert a single wide character into a complex character.
 */
int
__m_wc_cc(wint_t wc, cchar_t *cc)
{
    wchar_t wcs[2];

    if (wc == WEOF)
        return (-1);

    if (wc == 0) {
        /*
         * converting a null character to a complex character.
         * __m_wcs_cc assumes that the string is empty, so
         * just do it here.
         */
        cc->_f = 1;
        cc->_n = 1;
        cc->_co = 0;
        cc->_at = WA_NORMAL;
        cc->_wc[0] = 0;
        cc->_wc[1] = 0;
    } else {
        /* A real character */
        wcs[0] = (wchar_t)wc;
        wcs[1] = '\0';
        (void) __m_wcs_cc(wcs, WA_NORMAL, 0, cc);
    }

    return (0);
}

/*
 * Sort a complex character into a spacing character followed
 * by any non-spacing characters in increasing order of oridinal
 * values.  This facilitates both comparision and writting of
 * complex characters.  More than one spacing character is
 * considered an error.
 *
 * Return the spacing character's column width or -1 if more
 * than one spacing character appears in cc.
 */
int
__m_cc_sort(cchar_t *cc)
{
    wchar_t wc;
    int width, i, j, spacing;

    /* Find spacing character and place in as first element. */
    for (width = spacing = i = 0; i < cc->_n; ++i) {
        j = wcwidth(cc->_wc[i]);
        if (0 < j) {
            /* More than one spacing character is an error. */
            if (0 < width)
                return (-1);

            wc = cc->_wc[0];
            cc->_wc[0] = cc->_wc[i];
            cc->_wc[i] = wc;

            spacing = 1;
            width = j;
            break;
        }
    }

    /* Bubble sort small array. */
    for (i = spacing; i < cc->_n; ++i) {
        for (j = cc->_n - 1; i < j; --j) {
            if (cc->_wc[j-1] > cc->_wc[j]) {
                wc = cc->_wc[j];
                cc->_wc[j] = cc->_wc[j-1];
                cc->_wc[j-1]  = wc;
            }
        }
    }

    return (width);
}

/*
 * Return the first column of a multi-column character, in window.
 */
int
__m_cc_first(WINDOW *w, int y, int x)
{
    cchar_t *lp;

    for (lp = w->_line[y]; 0 < x; --x) {
        if (lp[x]._f)
            break;
    }

    return (x);
}

/*
 * Return the start of the next multi-column character, in window.
 */
int
__m_cc_next(WINDOW *w, int y, int x)
{
    cchar_t *lp;

    for (lp = w->_line[y]; ++x < w->_maxx; ) {
        if (lp[x]._f)
            break;
    }

    return (x);
}

/*
 * Return true if valid last column of a multi-column character.
 */
int
__m_cc_islast(WINDOW *w, int y, int x)
{
    int first, width;

    first = __m_cc_first(w, y, x);
    width = __m_cc_width(&w->_line[y][x]);

    return ((first + width) == (x + 1));
}

/*
 * Replace the character at the current cursor location
 * according to the column width of the character.  The
 * cursor does not advance.
 *
 * Return -1 if the character won't fit on the line and the background
 * was written in its place; else return the width of the character in
 * screen columns.
 */
/* ARGSUSED */
int
__m_cc_replace(WINDOW *w, int y, int x,
    const cchar_t *cc, int as_is)
{
    int i, width;
    cchar_t *cp, *np;

    width = __m_cc_width(cc);

    if (width <= 0)
        return (__m_cc_modify(w, y, x, cc));

    /*
     * If we try to write a broad character that would exceed the
     * right margin, then write the background character instead.
     */
    if (0 < width && w->_maxx < x + width) {
        (void) __m_cc_erase(w, y, x, y, w->_maxx-1);
        return (-1);
    }

    /*
     * Erase the region to be occupied by the new character.
     * __m_cc_erase() will erase whole characters so that
     * writing a multicolumn character that overwrites the
     * trailing and leading portions of two already existing
     * multicolumn characters, erases the remaining portions.
     */
    (void) __m_cc_erase(w, y, x, y, x + width - 1);

    /* Write the first column of the character. */
    cp = &w->_line[y][x++];
    if (cc->_wc[0] == L' ') {
        *cp = w->_bg;
        cp->_at = cc->_at | w->_fg._at;
        /*
         * This method fixes:
         * /tset/CAPIxcurses/fmvwaddchs/fmvwaddchs1{3}
         * /tset/CAPIxcurses/fwins_wch/fwins_wch1{5}
         */
        cp->_co = (cc->_co) ? cc->_co : w->_fg._co;
    } else {
        if (__m_wacs_cc(cc, cp)) {
            /*
             * __m_wacs_cc says ALTCHARSET should be cleared
             * ... Takes priority
             */
            cp->_at = (cc->_at | w->_fg._at) & ~WA_ALTCHARSET;
        } else {
            cp->_at = cc->_at | w->_fg._at;
        }
        cp->_co = (cc->_co) ? cc->_co : w->_fg._co;
    }

    /* Mark this as the first column of the character. */
    cp->_f = 1;

    /* Duplicate the character in every column the character occupies. */
    for (np = cp + 1, i = 1; i < width; ++i, ++x, ++np) {
        *np = *cp;
        np->_f = 0;
    }

    return (width);
}

int
__m_do_scroll(WINDOW *w, int y, int x, int *yp, int *xp)
{
    int code = OK;
    if (w->_maxx <= x)
        x = w->_maxx - 1;

    ++y;

    if (y == w->_bottom) {
        --y;
        if (w->_flags & W_CAN_SCROLL) {
            if (wscrl(w, 1) == ERR)
                return (ERR);
            x = 0;
            /* Test suite seems to want this */
            w->_flags |= W_FLUSH;
        } else {
#ifdef  BREAKS
            w->_curx = x;   /* Cheezy doing it here */
            w->_cury = y;
#endif  /* BREAKS */
            code = ERR; /* No scrolling allowed */
        }
    } else if (w->_maxy <= y) {
        y = w->_maxy - 1;
    } else {
        /*
         * The cursor wraps for any line (in and out of the scroll
         * region) except for the last line of the scroll region.
         */
        x = 0;
    }

    *yp = y;
    *xp = x;

    return (code);
}

/*
 * Add the character at the current cursor location
 * according to the column width of the character.
 * The cursor will be advanced.
 * Wrapping is done.
 *
 * Return ERR if adding the character causes the
 * screen to scroll, when it is disallowed.
 */
int
__m_cc_add(WINDOW *w, int y, int x,
    const cchar_t *cc, int as_is, int *yp, int *xp)
{
    int nx, width, code = ERR;

    switch (cc->_wc[0]) {
    case L'\t':
        nx = x + (8 - (x & 07));
        if (nx >= w->_maxx) {
            /* This fixes (scroll-disabled) */
            /* /tset/CAPIxcurses/fwaddch/fwaddch1{4} but */
            /* what does it break? */
            nx = w->_maxx;
        }
        if (__m_cc_erase(w, y, x, y, nx-1) == -1)
            goto error;
        x = nx;

        if (w->_maxx <= x) {
            if (__m_do_scroll(w, y, x, &y, &x) == ERR)
                goto error;
        }
        break;
    case L'\n':
        if (__m_cc_erase(w, y, x, y, w->_maxx-1) == -1)
            goto error;

        if (__m_do_scroll(w, y, x, &y, &x) == ERR)
            goto error;
        break;
    case L'\r':
        x = 0;
        break;
    case L'\b':
        if (0 < x)
            --x;
        else
            (void) beep();
        break;
    default:
        width = __m_cc_replace(w, y, x, cc, as_is);

        x += width;

        if (width < 0 || w->_maxx <= x) {
            if (__m_do_scroll(w, y, x, &y, &x) == ERR) {
                goto error;
            }

            if (width < 0)
                x += __m_cc_replace(w, y, x, cc, as_is);
        }
    }

    code = OK;
error:
    *yp = y;
    *xp = x;

    return (code);
}

/*
 * Stripped version of __m_cc_add which does much less special character
 * processing. Functions such as waddchnstr() are not supposed to do
 * any special character processing but what does one do when a '\n'
 * is sent? The test suite expects a new line to start...
 *
 * Return ERR if adding the character causes the
 * screen to scroll, when it is disallowed.
 */
int
__m_cc_add_k(WINDOW *w, int y, int x,
    const cchar_t *cc, int as_is, int *yp, int *xp)
{
    int width, code = ERR;

    switch (cc->_wc[0]) {
    case L'\n':
        if (__m_cc_erase(w, y, x, y, w->_maxx-1) == -1)
            goto error;

        if (__m_do_scroll(w, y, x, &y, &x) == ERR)
            goto error;
        break;
    default:
        width = __m_cc_replace(w, y, x, cc, as_is);
        x += width;
    }

    code = OK;
error:
    *yp = y;
    *xp = x;

    return (code);
}

/*
 * Append non-spacing characters to the a spacing character at (y, x).
 * Return -1 on error, else 0.
 */
int
__m_cc_modify(WINDOW *w, int y, int x, const cchar_t *cc)
{
    cchar_t *cp, tch;
    int i, j, width;

    x = __m_cc_first(w, y, x);
    cp = &w->_line[y][x];

    /* Is there enough room for the non-spacing characters. */
    if (_M_CCHAR_MAX < cp->_n + cc->_n)
        return (-1);

    for (i = cp->_n, j = 0; j < cc->_n; ++i, ++j)
        cp->_wc[i] = cc->_wc[j];
    cp->_n = (short)i;

    width = __m_cc_width(cp);

    __m_touch_locs(w, y, x, x + width);

    /* Assert that the modified spacing character is sorted. */
    (void) __m_cc_sort(cp);

    /* Dulicate in every column occupied by the spacing character. */
    while (0 < --width) {
        tch = *cp;
        cp[1] = tch;
        cp++;
    }

    return (0);
}

static void
__m_cc_erase_in_line(WINDOW *w, int y, int x, int lx, int bgWidth)
{
    cchar_t *cp;
    int i;

    if (x < w->_first[y])
        w->_first[y] = (short)x;

    for (cp = w->_line[y], i = 0; x <= lx; ++x, ++i) {
        cp[x] = w->_bg;
        /*
         * The start of each new character will be set true
         * while internal columns of the character will be
         * reset to false.
         */
        cp[x]._f = (short)(i % bgWidth == 0);
    }
    if (w->_last[y] < x)
        w->_last[y] = (short)x;
}

/* Window has a parent. Handle width chars overlapping with parent */
static void
__m_cc_erase_in_line_sub(WINDOW *w, int y, int x,
    int lx, int bgWidth, int parentBGWidth)
{
    cchar_t *cp;
    int i;
    int xi;
    int wmin, wmax;
    int wlx;
    int parentY = w->_begy + y;
    WINDOW  *parent = w->_parent;

    /* Switch to parent context and calculate limits */
    xi = x = __m_cc_first(parent, parentY, w->_begx + x);
    wlx = lx = __m_cc_next(parent, parentY, w->_begx + lx) - 1;
    if (wlx >= w->_begx + w->_maxx) wlx = w->_begx + w->_maxx - 1;

    for (cp = parent->_line[parentY]; x <= lx; ) {
        if ((x < w->_begx) || (x >= (w->_begx + w->_maxx))) {
            /* Outside target window */
            for (i = 0; x <= lx && i <= parentBGWidth; x++, i++) {
                cp[x] = parent->_bg;
                cp[x]._f = (i == 0);
            }
        } else {
            /* Inside target window */
            for (i = 0; x <= wlx; x++, i++) {
                cp[x] = w->_bg;
                cp[x]._f = (short)(i % bgWidth == 0);
            }
        }
    }
    wmax = x - w->_begx;        /* Defaults */
    wmin = xi - w->_begx;
    if ((xi < w->_begx) || (x >= w->_begx + w->_maxx)) {
        /* Overlaps parent. Must touch parent and child */
        int pmin, pmax;

        pmax = w->_begx;        /* Defaults */
        pmin = w->_begx + w->_maxx;
        if (xi < w->_begx) {
            wmin = 0;
            pmin = xi;
        }
        if (x >= w->_begx + w->_maxx) {
            /* Ends right of target window */
            wmax = w->_maxx;
            pmax = x;
        }
        if (pmin < parent->_first[parentY])
            parent->_first[parentY] = (short)pmin;
        if (pmax > parent->_last[parentY])
            parent->_last[parentY] = (short)pmax;
    }
    if (wmin < w->_first[y])
        w->_first[y] = (short)wmin;
    if (wmax > w->_last[y])
        w->_last[y] = (short)wmax;
}

/*
 * Erase region from (y,x) to (ly, lx) inclusive.  The
 * region is extended left and right in the case where
 * the portions of a multicolumn characters are erased.
 *
 * Return -1 if the region is not an integral multiple
 * of the background character, else zero for success.
 */
int
__m_cc_erase(WINDOW *w, int y, int x, int ly, int lx)
{
    int bgWidth;

    if (ly < y)
        return (-1);

    if (w->_maxy <= ly)
        ly = w->_maxy - 1;

    /*
     * Is the region to blank out an integral width of the
     * background character?
     */
    bgWidth = __m_cc_width(&w->_bg);

    if (bgWidth <= 0)
        return (-1);

    /*
     * Erase Pattern will look like:
     *          EEEEEEE|
     *  EEEEEEEEEEEEEEE|
     *  EEEEEEEEEEE    |
     */
    if (w->_parent) {
        /*
         * Use slower alg. for subwindows.
         * They might erase stuff in parent-context
         */
        int parentBGWidth = __m_cc_width(&w->_parent->_bg);
        for (; y < ly; ++y, x = 0) {
            __m_cc_erase_in_line_sub(w, y, x, w->_maxx-1,
                bgWidth, parentBGWidth);
        }
        __m_cc_erase_in_line_sub(w, y, x, lx, bgWidth, parentBGWidth);
    } else {
        /* Root windows - no need to work in parent context at all */
        if (w->_maxx <= lx)
            lx = w->_maxx - 1;

        /*
         * Erase from first whole character (inclusive) to next
         * character (exclusive).
         */
        x = __m_cc_first(w, y, x);
        lx = __m_cc_next(w, ly, lx) - 1;

        for (; y < ly; ++y, x = 0) {
            __m_cc_erase_in_line(w, y, x, w->_maxx-1, bgWidth);
        }
        __m_cc_erase_in_line(w, y, x, lx, bgWidth);
    }
    return (0);
}

/*
 * Expand the character to the left or right of the given position.
 * Return the value returned by __m_cc_replace().
 */
int
__m_cc_expand(WINDOW *w, int y, int x, int side)
{
    cchar_t cc;
    int dx, width;

    width = __m_cc_width(&w->_line[y][x]);

    if (side < 0)
        dx = __m_cc_next(w, y, x) - width;
    else if (0 < side)
        dx = __m_cc_first(w, y, x);
    else
        return (-1);

    /*
     * __m_cc_replace() will erase the region containing
     * the character we want to expand.
     */
    cc = w->_line[y][x];

    return (__m_cc_replace(w, y, dx, &cc, 0));
}

/* Revised version of __m_cc_compare() to compare only the char parts */

int
__m_cc_equal(const cchar_t *c1, const cchar_t *c2)
{
    int i;

    if (c1->_f != c2->_f)
        return (0);
    if (c1->_n != c2->_n)
        return (0);
    for (i = 0; i < c1->_n; ++i)
        if (c1->_wc[i] != c2->_wc[i])
            return (0);
    return (1);
}

/*
 * Return true if characters are equal.
 *
 * NOTE to guarantee correct results, make sure that both
 * characters have been passed through __m_cc_sort().
 */
int
__m_cc_compare(const cchar_t *c1, const cchar_t *c2, int exact)
{
    int i;

    if (exact && c1->_f != c2->_f)
        return (0);
    if (c1->_n != c2->_n)
        return (0);
    if ((c1->_at & ~WA_COOKIE) != (c2->_at & ~WA_COOKIE))
        return (0);
    if (c1->_co != c2->_co)
        return (0);

    for (i = 0; i < c1->_n; ++i)
        if (c1->_wc[i] != c2->_wc[i])
            return (0);

    return (1);
}

/*
 * Write to the stream the character portion of a cchar_t.
 */
int
__m_cc_write(const cchar_t *cc)
{
    int j;
    size_t  i;
    char    mb[MB_LEN_MAX];
/*
 * 4131273 UNIX98: xcurses library renders complex characters incorrectly
 */
    int backed_up = 0;

    for (i = 0; i < cc->_n; ++i) {
        j = wctomb(mb, cc->_wc[i]);
        if (j == -1)
            return (EOF);
        if (i == 1) {
            /*
             * Move cursor back where it was
             */
            if (fwrite(cursor_left, 1, strlen(cursor_left),
                __m_screen->_of) == 0) {
                return (EOF);
            }
            backed_up = 1;
        }
        if (fwrite(mb, sizeof (*mb), (size_t)j, __m_screen->_of) == 0) {
            return (EOF);
        }
    }
    if (backed_up) {
        /*
         * Move cursor back where it was
         */
        if (fwrite(cursor_right, 1, strlen(cursor_right),
            __m_screen->_of) == 0) {
            return (EOF);
        }
    }

    __m_screen->_flags |= W_FLUSH;
    return (0);
}