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/* vi:set ts=8 sts=4 sw=4:
 *
 * VIM - Vi IMproved    by Bram Moolenaar
 *
 * Do ":help uganda"  in Vim to read copying and usage conditions.
 * Do ":help credits" in Vim to see a list of people who contributed.
 * See README.txt for an overview of the Vim source code.
 */

/*
 * arabic.c: functions for Arabic language
 *
 * Included by main.c, when FEAT_ARABIC & FEAT_GUI is defined.
 *
 * --
 *
 * Author: Nadim Shaikli & Isam Bayazidi
 *
 */

static int  A_is_a __ARGS((int cur_c));
static int  A_is_s __ARGS((int cur_c));
static int  A_is_f __ARGS((int cur_c));
static int  chg_c_a2s __ARGS((int cur_c));
static int  chg_c_a2i __ARGS((int cur_c));
static int  chg_c_a2m __ARGS((int cur_c));
static int  chg_c_a2f __ARGS((int cur_c));
static int  chg_c_i2m __ARGS((int cur_c));
static int  chg_c_f2m __ARGS((int cur_c));
static int  chg_c_laa2i __ARGS((int hid_c));
static int  chg_c_laa2f __ARGS((int hid_c));
static int  half_shape __ARGS((int c));
static int  A_firstc_laa __ARGS((int c1, int c));
static int  A_is_harakat __ARGS((int c));
static int  A_is_iso __ARGS((int c));
static int  A_is_formb __ARGS((int c));
static int  A_is_ok __ARGS((int c));
static int  A_is_valid __ARGS((int c));
static int  A_is_special __ARGS((int c));


/*
 * Returns True if c is an ISO-8859-6 shaped ARABIC letter (user entered)
 */
    static int
A_is_a(cur_c)
    int cur_c;
{
    switch (cur_c)
    {
        case a_HAMZA:
        case a_ALEF_MADDA:
        case a_ALEF_HAMZA_ABOVE:
        case a_WAW_HAMZA:
        case a_ALEF_HAMZA_BELOW:
        case a_YEH_HAMZA:
        case a_ALEF:
        case a_BEH:
        case a_TEH_MARBUTA:
        case a_TEH:
        case a_THEH:
        case a_JEEM:
        case a_HAH:
        case a_KHAH:
        case a_DAL:
        case a_THAL:
        case a_REH:
        case a_ZAIN:
        case a_SEEN:
        case a_SHEEN:
        case a_SAD:
        case a_DAD:
        case a_TAH:
        case a_ZAH:
        case a_AIN:
        case a_GHAIN:
        case a_TATWEEL:
        case a_FEH:
        case a_QAF:
        case a_KAF:
        case a_LAM:
        case a_MEEM:
        case a_NOON:
        case a_HEH:
        case a_WAW:
        case a_ALEF_MAKSURA:
        case a_YEH:
            return TRUE;
    }

    return FALSE;
}


/*
 * Returns True if c is an Isolated Form-B ARABIC letter
 */
    static int
A_is_s(cur_c)
    int cur_c;
{
    switch (cur_c)
    {
        case a_s_HAMZA:
        case a_s_ALEF_MADDA:
        case a_s_ALEF_HAMZA_ABOVE:
        case a_s_WAW_HAMZA:
        case a_s_ALEF_HAMZA_BELOW:
        case a_s_YEH_HAMZA:
        case a_s_ALEF:
        case a_s_BEH:
        case a_s_TEH_MARBUTA:
        case a_s_TEH:
        case a_s_THEH:
        case a_s_JEEM:
        case a_s_HAH:
        case a_s_KHAH:
        case a_s_DAL:
        case a_s_THAL:
        case a_s_REH:
        case a_s_ZAIN:
        case a_s_SEEN:
        case a_s_SHEEN:
        case a_s_SAD:
        case a_s_DAD:
        case a_s_TAH:
        case a_s_ZAH:
        case a_s_AIN:
        case a_s_GHAIN:
        case a_s_FEH:
        case a_s_QAF:
        case a_s_KAF:
        case a_s_LAM:
        case a_s_MEEM:
        case a_s_NOON:
        case a_s_HEH:
        case a_s_WAW:
        case a_s_ALEF_MAKSURA:
        case a_s_YEH:
            return TRUE;
    }

    return FALSE;
}


/*
 * Returns True if c is a Final shape of an ARABIC letter
 */
    static int
A_is_f(cur_c)
    int cur_c;
{
    switch (cur_c)
    {
        case a_f_ALEF_MADDA:
        case a_f_ALEF_HAMZA_ABOVE:
        case a_f_WAW_HAMZA:
        case a_f_ALEF_HAMZA_BELOW:
        case a_f_YEH_HAMZA:
        case a_f_ALEF:
        case a_f_BEH:
        case a_f_TEH_MARBUTA:
        case a_f_TEH:
        case a_f_THEH:
        case a_f_JEEM:
        case a_f_HAH:
        case a_f_KHAH:
        case a_f_DAL:
        case a_f_THAL:
        case a_f_REH:
        case a_f_ZAIN:
        case a_f_SEEN:
        case a_f_SHEEN:
        case a_f_SAD:
        case a_f_DAD:
        case a_f_TAH:
        case a_f_ZAH:
        case a_f_AIN:
        case a_f_GHAIN:
        case a_f_FEH:
        case a_f_QAF:
        case a_f_KAF:
        case a_f_LAM:
        case a_f_MEEM:
        case a_f_NOON:
        case a_f_HEH:
        case a_f_WAW:
        case a_f_ALEF_MAKSURA:
        case a_f_YEH:
        case a_f_LAM_ALEF_MADDA_ABOVE:
        case a_f_LAM_ALEF_HAMZA_ABOVE:
        case a_f_LAM_ALEF_HAMZA_BELOW:
        case a_f_LAM_ALEF:
            return TRUE;
    }
    return FALSE;
}


/*
 * Change shape - from ISO-8859-6/Isolated to Form-B Isolated
 */
    static int
chg_c_a2s(cur_c)
    int cur_c;
{
    int tempc;

    switch (cur_c)
    {
        case a_HAMZA:
            tempc = a_s_HAMZA;
            break;
        case a_ALEF_MADDA:
            tempc = a_s_ALEF_MADDA;
            break;
        case a_ALEF_HAMZA_ABOVE:
            tempc = a_s_ALEF_HAMZA_ABOVE;
            break;
        case a_WAW_HAMZA:
            tempc = a_s_WAW_HAMZA;
            break;
        case a_ALEF_HAMZA_BELOW:
            tempc = a_s_ALEF_HAMZA_BELOW;
            break;
        case a_YEH_HAMZA:
            tempc = a_s_YEH_HAMZA;
            break;
        case a_ALEF:
            tempc = a_s_ALEF;
            break;
        case a_TEH_MARBUTA:
            tempc = a_s_TEH_MARBUTA;
            break;
        case a_DAL:
            tempc = a_s_DAL;
            break;
        case a_THAL:
            tempc = a_s_THAL;
            break;
        case a_REH:
            tempc = a_s_REH;
            break;
        case a_ZAIN:
            tempc = a_s_ZAIN;
            break;
        case a_TATWEEL:                 /* exceptions */
            tempc = cur_c;
            break;
        case a_WAW:
            tempc = a_s_WAW;
            break;
        case a_ALEF_MAKSURA:
            tempc = a_s_ALEF_MAKSURA;
            break;
        case a_BEH:
            tempc = a_s_BEH;
            break;
        case a_TEH:
            tempc = a_s_TEH;
            break;
        case a_THEH:
            tempc = a_s_THEH;
            break;
        case a_JEEM:
            tempc = a_s_JEEM;
            break;
        case a_HAH:
            tempc = a_s_HAH;
            break;
        case a_KHAH:
            tempc = a_s_KHAH;
            break;
        case a_SEEN:
            tempc = a_s_SEEN;
            break;
        case a_SHEEN:
            tempc = a_s_SHEEN;
            break;
        case a_SAD:
            tempc = a_s_SAD;
            break;
        case a_DAD:
            tempc = a_s_DAD;
            break;
        case a_TAH:
            tempc = a_s_TAH;
            break;
        case a_ZAH:
            tempc = a_s_ZAH;
            break;
        case a_AIN:
            tempc = a_s_AIN;
            break;
        case a_GHAIN:
            tempc = a_s_GHAIN;
            break;
        case a_FEH:
            tempc = a_s_FEH;
            break;
        case a_QAF:
            tempc = a_s_QAF;
            break;
        case a_KAF:
            tempc = a_s_KAF;
            break;
        case a_LAM:
            tempc = a_s_LAM;
            break;
        case a_MEEM:
            tempc = a_s_MEEM;
            break;
        case a_NOON:
            tempc = a_s_NOON;
            break;
        case a_HEH:
            tempc = a_s_HEH;
            break;
        case a_YEH:
            tempc = a_s_YEH;
            break;
        default:
            tempc = 0;
    }

    return tempc;
}


/*
 * Change shape - from ISO-8859-6/Isolated to Initial
 */
    static int
chg_c_a2i(cur_c)
    int cur_c;
{
    int tempc;

    switch (cur_c)
    {
        case a_YEH_HAMZA:
            tempc = a_i_YEH_HAMZA;
            break;
        case a_HAMZA:                   /* exceptions */
            tempc = a_s_HAMZA;
            break;
        case a_ALEF_MADDA:              /* exceptions */
            tempc = a_s_ALEF_MADDA;
            break;
        case a_ALEF_HAMZA_ABOVE:        /* exceptions */
            tempc = a_s_ALEF_HAMZA_ABOVE;
            break;
        case a_WAW_HAMZA:               /* exceptions */
            tempc = a_s_WAW_HAMZA;
            break;
        case a_ALEF_HAMZA_BELOW:        /* exceptions */
            tempc = a_s_ALEF_HAMZA_BELOW;
            break;
        case a_ALEF:                    /* exceptions */
            tempc = a_s_ALEF;
            break;
        case a_TEH_MARBUTA:             /* exceptions */
            tempc = a_s_TEH_MARBUTA;
            break;
        case a_DAL:                     /* exceptions */
            tempc = a_s_DAL;
            break;
        case a_THAL:                    /* exceptions */
            tempc = a_s_THAL;
            break;
        case a_REH:                     /* exceptions */
            tempc = a_s_REH;
            break;
        case a_ZAIN:                    /* exceptions */
            tempc = a_s_ZAIN;
            break;
        case a_TATWEEL:                 /* exceptions */
            tempc = cur_c;
            break;
        case a_WAW:                     /* exceptions */
            tempc = a_s_WAW;
            break;
        case a_ALEF_MAKSURA:            /* exceptions */
            tempc = a_s_ALEF_MAKSURA;
            break;
        case a_BEH:
            tempc = a_i_BEH;
            break;
        case a_TEH:
            tempc = a_i_TEH;
            break;
        case a_THEH:
            tempc = a_i_THEH;
            break;
        case a_JEEM:
            tempc = a_i_JEEM;
            break;
        case a_HAH:
            tempc = a_i_HAH;
            break;
        case a_KHAH:
            tempc = a_i_KHAH;
            break;
        case a_SEEN:
            tempc = a_i_SEEN;
            break;
        case a_SHEEN:
            tempc = a_i_SHEEN;
            break;
        case a_SAD:
            tempc = a_i_SAD;
            break;
        case a_DAD:
            tempc = a_i_DAD;
            break;
        case a_TAH:
            tempc = a_i_TAH;
            break;
        case a_ZAH:
            tempc = a_i_ZAH;
            break;
        case a_AIN:
            tempc = a_i_AIN;
            break;
        case a_GHAIN:
            tempc = a_i_GHAIN;
            break;
        case a_FEH:
            tempc = a_i_FEH;
            break;
        case a_QAF:
            tempc = a_i_QAF;
            break;
        case a_KAF:
            tempc = a_i_KAF;
            break;
        case a_LAM:
            tempc = a_i_LAM;
            break;
        case a_MEEM:
            tempc = a_i_MEEM;
            break;
        case a_NOON:
            tempc = a_i_NOON;
            break;
        case a_HEH:
            tempc = a_i_HEH;
            break;
        case a_YEH:
            tempc = a_i_YEH;
            break;
        default:
            tempc = 0;
    }

    return tempc;
}


/*
 * Change shape - from ISO-8859-6/Isolated to Medial
 */
    static int
chg_c_a2m(cur_c)
    int cur_c;
{
    int tempc;

    switch (cur_c)
    {
        case a_HAMZA:                   /* exception */
            tempc = a_s_HAMZA;
            break;
        case a_ALEF_MADDA:              /* exception */
            tempc = a_f_ALEF_MADDA;
            break;
        case a_ALEF_HAMZA_ABOVE:        /* exception */
            tempc = a_f_ALEF_HAMZA_ABOVE;
            break;
        case a_WAW_HAMZA:               /* exception */
            tempc = a_f_WAW_HAMZA;
            break;
        case a_ALEF_HAMZA_BELOW:        /* exception */
            tempc = a_f_ALEF_HAMZA_BELOW;
            break;
        case a_YEH_HAMZA:
            tempc = a_m_YEH_HAMZA;
            break;
        case a_ALEF:                    /* exception */
            tempc = a_f_ALEF;
            break;
        case a_BEH:
            tempc = a_m_BEH;
            break;
        case a_TEH_MARBUTA:             /* exception */
            tempc = a_f_TEH_MARBUTA;
            break;
        case a_TEH:
            tempc = a_m_TEH;
            break;
        case a_THEH:
            tempc = a_m_THEH;
            break;
        case a_JEEM:
            tempc = a_m_JEEM;
            break;
        case a_HAH:
            tempc = a_m_HAH;
            break;
        case a_KHAH:
            tempc = a_m_KHAH;
            break;
        case a_DAL:                     /* exception */
            tempc = a_f_DAL;
            break;
        case a_THAL:                    /* exception */
            tempc = a_f_THAL;
            break;
        case a_REH:                     /* exception */
            tempc = a_f_REH;
            break;
        case a_ZAIN:                    /* exception */
            tempc = a_f_ZAIN;
            break;
        case a_SEEN:
            tempc = a_m_SEEN;
            break;
        case a_SHEEN:
            tempc = a_m_SHEEN;
            break;
        case a_SAD:
            tempc = a_m_SAD;
            break;
        case a_DAD:
            tempc = a_m_DAD;
            break;
        case a_TAH:
            tempc = a_m_TAH;
            break;
        case a_ZAH:
            tempc = a_m_ZAH;
            break;
        case a_AIN:
            tempc = a_m_AIN;
            break;
        case a_GHAIN:
            tempc = a_m_GHAIN;
            break;
        case a_TATWEEL:                 /* exception */
            tempc = cur_c;
            break;
        case a_FEH:
            tempc = a_m_FEH;
            break;
        case a_QAF:
            tempc = a_m_QAF;
            break;
        case a_KAF:
            tempc = a_m_KAF;
            break;
        case a_LAM:
            tempc = a_m_LAM;
            break;
        case a_MEEM:
            tempc = a_m_MEEM;
            break;
        case a_NOON:
            tempc = a_m_NOON;
            break;
        case a_HEH:
            tempc = a_m_HEH;
            break;
        case a_WAW:                     /* exception */
            tempc = a_f_WAW;
            break;
        case a_ALEF_MAKSURA:            /* exception */
            tempc = a_f_ALEF_MAKSURA;
            break;
        case a_YEH:
            tempc = a_m_YEH;
            break;
        default:
            tempc = 0;
    }

    return tempc;
}


/*
 * Change shape - from ISO-8859-6/Isolated to final
 */
    static int
chg_c_a2f(cur_c)
    int cur_c;
{
    int tempc;

    /* NOTE: these encodings need to be accounted for

        a_f_ALEF_MADDA;
        a_f_ALEF_HAMZA_ABOVE;
        a_f_ALEF_HAMZA_BELOW;
        a_f_LAM_ALEF_MADDA_ABOVE;
        a_f_LAM_ALEF_HAMZA_ABOVE;
        a_f_LAM_ALEF_HAMZA_BELOW;
        */

    switch (cur_c)
    {
        case a_HAMZA:                   /* exception */
            tempc = a_s_HAMZA;
            break;
        case a_ALEF_MADDA:
            tempc = a_f_ALEF_MADDA;
            break;
        case a_ALEF_HAMZA_ABOVE:
            tempc = a_f_ALEF_HAMZA_ABOVE;
            break;
        case a_WAW_HAMZA:
            tempc = a_f_WAW_HAMZA;
            break;
        case a_ALEF_HAMZA_BELOW:
            tempc = a_f_ALEF_HAMZA_BELOW;
            break;
        case a_YEH_HAMZA:
            tempc = a_f_YEH_HAMZA;
            break;
        case a_ALEF:
            tempc = a_f_ALEF;
            break;
        case a_BEH:
            tempc = a_f_BEH;
            break;
        case a_TEH_MARBUTA:
            tempc = a_f_TEH_MARBUTA;
            break;
        case a_TEH:
            tempc = a_f_TEH;
            break;
        case a_THEH:
            tempc = a_f_THEH;
            break;
        case a_JEEM:
            tempc = a_f_JEEM;
            break;
        case a_HAH:
            tempc = a_f_HAH;
            break;
        case a_KHAH:
            tempc = a_f_KHAH;
            break;
        case a_DAL:
            tempc = a_f_DAL;
            break;
        case a_THAL:
            tempc = a_f_THAL;
            break;
        case a_REH:
            tempc = a_f_REH;
            break;
        case a_ZAIN:
            tempc = a_f_ZAIN;
            break;
        case a_SEEN:
            tempc = a_f_SEEN;
            break;
        case a_SHEEN:
            tempc = a_f_SHEEN;
            break;
        case a_SAD:
            tempc = a_f_SAD;
            break;
        case a_DAD:
            tempc = a_f_DAD;
            break;
        case a_TAH:
            tempc = a_f_TAH;
            break;
        case a_ZAH:
            tempc = a_f_ZAH;
            break;
        case a_AIN:
            tempc = a_f_AIN;
            break;
        case a_GHAIN:
            tempc = a_f_GHAIN;
            break;
        case a_TATWEEL:                 /* exception */
            tempc = cur_c;
            break;
        case a_FEH:
            tempc = a_f_FEH;
            break;
        case a_QAF:
            tempc = a_f_QAF;
            break;
        case a_KAF:
            tempc = a_f_KAF;
            break;
        case a_LAM:
            tempc = a_f_LAM;
            break;
        case a_MEEM:
            tempc = a_f_MEEM;
            break;
        case a_NOON:
            tempc = a_f_NOON;
            break;
        case a_HEH:
            tempc = a_f_HEH;
            break;
        case a_WAW:
            tempc = a_f_WAW;
            break;
        case a_ALEF_MAKSURA:
            tempc = a_f_ALEF_MAKSURA;
            break;
        case a_YEH:
            tempc = a_f_YEH;
            break;
        default:
            tempc = 0;
    }

    return tempc;
}


/*
 * Change shape - from Initial to Medial
 */
    static int
chg_c_i2m(cur_c)
    int cur_c;
{
    int tempc;

    switch (cur_c)
    {
        case a_i_YEH_HAMZA:
            tempc = a_m_YEH_HAMZA;
            break;
        case a_i_BEH:
            tempc = a_m_BEH;
            break;
        case a_i_TEH:
            tempc = a_m_TEH;
            break;
        case a_i_THEH:
            tempc = a_m_THEH;
            break;
        case a_i_JEEM:
            tempc = a_m_JEEM;
            break;
        case a_i_HAH:
            tempc = a_m_HAH;
            break;
        case a_i_KHAH:
            tempc = a_m_KHAH;
            break;
        case a_i_SEEN:
            tempc = a_m_SEEN;
            break;
        case a_i_SHEEN:
            tempc = a_m_SHEEN;
            break;
        case a_i_SAD:
            tempc = a_m_SAD;
            break;
        case a_i_DAD:
            tempc = a_m_DAD;
            break;
        case a_i_TAH:
            tempc = a_m_TAH;
            break;
        case a_i_ZAH:
            tempc = a_m_ZAH;
            break;
        case a_i_AIN:
            tempc = a_m_AIN;
            break;
        case a_i_GHAIN:
            tempc = a_m_GHAIN;
            break;
        case a_i_FEH:
            tempc = a_m_FEH;
            break;
        case a_i_QAF:
            tempc = a_m_QAF;
            break;
        case a_i_KAF:
            tempc = a_m_KAF;
            break;
        case a_i_LAM:
            tempc = a_m_LAM;
            break;
        case a_i_MEEM:
            tempc = a_m_MEEM;
            break;
        case a_i_NOON:
            tempc = a_m_NOON;
            break;
        case a_i_HEH:
            tempc = a_m_HEH;
            break;
        case a_i_YEH:
            tempc = a_m_YEH;
            break;
        default:
            tempc = 0;
    }

    return tempc;
}


/*
 * Change shape - from Final to Medial
 */
    static int
chg_c_f2m(cur_c)
    int cur_c;
{
    int tempc;

    switch (cur_c)
    {
        /* NOTE: these encodings are multi-positional, no ?
           case a_f_ALEF_MADDA:
           case a_f_ALEF_HAMZA_ABOVE:
           case a_f_ALEF_HAMZA_BELOW:
           */
        case a_f_YEH_HAMZA:
            tempc = a_m_YEH_HAMZA;
            break;
        case a_f_WAW_HAMZA:             /* exceptions */
        case a_f_ALEF:
        case a_f_TEH_MARBUTA:
        case a_f_DAL:
        case a_f_THAL:
        case a_f_REH:
        case a_f_ZAIN:
        case a_f_WAW:
        case a_f_ALEF_MAKSURA:
            tempc = cur_c;
            break;
        case a_f_BEH:
            tempc = a_m_BEH;
            break;
        case a_f_TEH:
            tempc = a_m_TEH;
            break;
        case a_f_THEH:
            tempc = a_m_THEH;
            break;
        case a_f_JEEM:
            tempc = a_m_JEEM;
            break;
        case a_f_HAH:
            tempc = a_m_HAH;
            break;
        case a_f_KHAH:
            tempc = a_m_KHAH;
            break;
        case a_f_SEEN:
            tempc = a_m_SEEN;
            break;
        case a_f_SHEEN:
            tempc = a_m_SHEEN;
            break;
        case a_f_SAD:
            tempc = a_m_SAD;
            break;
        case a_f_DAD:
            tempc = a_m_DAD;
            break;
        case a_f_TAH:
            tempc = a_m_TAH;
            break;
        case a_f_ZAH:
            tempc = a_m_ZAH;
            break;
        case a_f_AIN:
            tempc = a_m_AIN;
            break;
        case a_f_GHAIN:
            tempc = a_m_GHAIN;
            break;
        case a_f_FEH:
            tempc = a_m_FEH;
            break;
        case a_f_QAF:
            tempc = a_m_QAF;
            break;
        case a_f_KAF:
            tempc = a_m_KAF;
            break;
        case a_f_LAM:
            tempc = a_m_LAM;
            break;
        case a_f_MEEM:
            tempc = a_m_MEEM;
            break;
        case a_f_NOON:
            tempc = a_m_NOON;
            break;
        case a_f_HEH:
            tempc = a_m_HEH;
            break;
        case a_f_YEH:
            tempc = a_m_YEH;
            break;
            /* NOTE: these encodings are multi-positional, no ?
                case a_f_LAM_ALEF_MADDA_ABOVE:
                case a_f_LAM_ALEF_HAMZA_ABOVE:
                case a_f_LAM_ALEF_HAMZA_BELOW:
                case a_f_LAM_ALEF:
                */
        default:
            tempc = 0;
    }

    return tempc;
}


/*
 * Change shape - from Combination (2 char) to an Isolated
 */
    static int
chg_c_laa2i(hid_c)
    int hid_c;
{
    int tempc;

    switch (hid_c)
    {
        case a_ALEF_MADDA:
            tempc = a_s_LAM_ALEF_MADDA_ABOVE;
            break;
        case a_ALEF_HAMZA_ABOVE:
            tempc = a_s_LAM_ALEF_HAMZA_ABOVE;
            break;
        case a_ALEF_HAMZA_BELOW:
            tempc = a_s_LAM_ALEF_HAMZA_BELOW;
            break;
        case a_ALEF:
            tempc = a_s_LAM_ALEF;
            break;
        default:
            tempc = 0;
    }

    return tempc;
}


/*
 * Change shape - from Combination-Isolated to Final
 */
    static int
chg_c_laa2f(hid_c)
    int hid_c;
{
    int tempc;

    switch (hid_c)
    {
        case a_ALEF_MADDA:
            tempc = a_f_LAM_ALEF_MADDA_ABOVE;
            break;
        case a_ALEF_HAMZA_ABOVE:
            tempc = a_f_LAM_ALEF_HAMZA_ABOVE;
            break;
        case a_ALEF_HAMZA_BELOW:
            tempc = a_f_LAM_ALEF_HAMZA_BELOW;
            break;
        case a_ALEF:
            tempc = a_f_LAM_ALEF;
            break;
        default:
            tempc = 0;
    }

    return tempc;
}

/*
 * Do "half-shaping" on character "c".  Return zero if no shaping.
 */
    static int
half_shape(c)
    int         c;
{
    if (A_is_a(c))
        return chg_c_a2i(c);
    if (A_is_valid(c) && A_is_f(c))
        return chg_c_f2m(c);
    return 0;
}

/*
 * Do Arabic shaping on character "c".  Returns the shaped character.
 * out:    "ccp" points to the first byte of the character to be shaped.
 * in/out: "c1p" points to the first composing char for "c".
 * in:     "prev_c"  is the previous character (not shaped)
 * in:     "prev_c1" is the first composing char for the previous char
 *                   (not shaped)
 * in:     "next_c"  is the next character (not shaped).
 */
    int
arabic_shape(c, ccp, c1p, prev_c, prev_c1, next_c)
    int         c;
    int         *ccp;
    int         *c1p;
    int         prev_c;
    int         prev_c1;
    int         next_c;
{
    int         curr_c;
    int         shape_c;
    int         curr_laa;
    int         prev_laa;

    /* Deal only with Arabic character, pass back all others */
    if (!A_is_ok(c))
        return c;

    /* half-shape current and previous character */
    shape_c = half_shape(prev_c);

    /* Save away current character */
    curr_c = c;

    curr_laa = A_firstc_laa(c, *c1p);
    prev_laa = A_firstc_laa(prev_c, prev_c1);

    if (curr_laa)
    {
        if (A_is_valid(prev_c) && !A_is_f(shape_c)
                                         && !A_is_s(shape_c) && !prev_laa)
            curr_c = chg_c_laa2f(curr_laa);
        else
            curr_c = chg_c_laa2i(curr_laa);

        /* Remove the composing character */
        *c1p = 0;
    }
    else if (!A_is_valid(prev_c) && A_is_valid(next_c))
        curr_c = chg_c_a2i(c);
    else if (!shape_c || A_is_f(shape_c) || A_is_s(shape_c) || prev_laa)
        curr_c = A_is_valid(next_c) ? chg_c_a2i(c) : chg_c_a2s(c);
    else if (A_is_valid(next_c))
        curr_c = A_is_iso(c) ? chg_c_a2m(c) : chg_c_i2m(c);
    else if (A_is_valid(prev_c))
        curr_c = chg_c_a2f(c);
    else
        curr_c = chg_c_a2s(c);

    /* Sanity check -- curr_c should, in the future, never be 0.
     * We should, in the future, insert a fatal error here. */
    if (curr_c == NUL)
        curr_c = c;

    if (curr_c != c && ccp != NULL)
    {
        char_u buf[MB_MAXBYTES];

        /* Update the first byte of the character. */
        (*mb_char2bytes)(curr_c, buf);
        *ccp = buf[0];
    }

    /* Return the shaped character */
    return curr_c;
}


/*
 * A_firstc_laa returns first character of LAA combination if it exists
 */
    static int
A_firstc_laa(c, c1)
    int c;      /* base character */
    int c1;     /* first composing character */
{
    if (c1 != NUL && c == a_LAM && !A_is_harakat(c1))
        return c1;
    return 0;
}


/*
 * A_is_harakat returns TRUE if 'c' is an Arabic Harakat character
 *              (harakat/tanween)
 */
    static int
A_is_harakat(c)
    int c;
{
    return (c >= a_FATHATAN && c <= a_SUKUN);
}


/*
 * A_is_iso returns TRUE if 'c' is an Arabic ISO-8859-6 character
 *              (alphabet/number/punctuation)
 */
    static int
A_is_iso(c)
    int c;
{
    return ((c >= a_HAMZA && c <= a_GHAIN)
            || (c >= a_TATWEEL && c <= a_HAMZA_BELOW)
            || c == a_MINI_ALEF);
}


/*
 * A_is_formb returns TRUE if 'c' is an Arabic 10646-1 FormB character
 *              (alphabet/number/punctuation)
 */
    static int
A_is_formb(c)
    int c;
{
    return ((c >= a_s_FATHATAN && c <= a_s_DAMMATAN)
            || c == a_s_KASRATAN
            || (c >= a_s_FATHA && c <= a_f_LAM_ALEF)
            || c == a_BYTE_ORDER_MARK);
}


/*
 * A_is_ok returns TRUE if 'c' is an Arabic 10646 (8859-6 or Form-B)
 */
    static int
A_is_ok(c)
    int c;
{
    return (A_is_iso(c) || A_is_formb(c));
}


/*
 * A_is_valid returns TRUE if 'c' is an Arabic 10646 (8859-6 or Form-B)
 *              with some exceptions/exclusions
 */
    static int
A_is_valid(c)
    int c;
{
    return (A_is_ok(c) && !A_is_special(c));
}


/*
 * A_is_special returns TRUE if 'c' is not a special Arabic character.
 *              Specials don't adhere to most of the rules.
 */
    static int
A_is_special(c)
    int c;
{
    return (c == a_HAMZA || c == a_s_HAMZA);
}