#ifndef lint
static char sccs_id[] = "%W%	(TriChlor) %G% %U%";
#endif  /* lint */

/*
 * Vncompos.c is an implementation of the efficient and flexible
 * composition algorithm due to Dr. Hoc Ngo of the Viet-Std group.
 */

#ifdef _WINDOWS
#include <windows.h>
#endif
#include <stdio.h>
#include "portable.h"
#include "charset.h"
#include "vnkeys.h"
#include "vncompos.h"

/* short-hand definitions */
#define	C_state	(Co_data->state)
#define	C1	(Co_data->c1)
#define	C2	(Co_data->c2)
#define	C3	(Co_data->c3)
#define	I1	(Co_data->i1)
#define	I2	(Co_data->i2)
#define	I3	(Co_data->i3)

static u_char	orig_icode[256];
static u_char	icode[256];

/*********** RHcode **********/
static u_char RHcode[37] = {
    /* RHcode[all others]	*/ 0x00,
    /* RHcode[C_D]		*/ 0x40,
    /* RHcode[C_A]		*/ 0x1f,
    /* RHcode[C_A_breve]	*/ 0x07,
    /* RHcode[C_A_circumflex]	*/ 0x07,
	/* skipped 		*/ 0x00,
    /* RHcode[C_E]		*/ 0x17,
    /* RHcode[C_I]		*/ 0x07,
    /* RHcode[C_E_circumflex]	*/ 0x07,
    /* RHcode[C_O]		*/ 0x37,
    /* RHcode[C_U]		*/ 0x27,
    /* RHcode[C_O_circumflex]	*/ 0x07,
    /* RHcode[C_O_horn]		*/ 0x07,
    /* RHcode[C_U_horn]		*/ 0x07,
    /* RHcode[C_Y]		*/ 0x07,
    /* RHcode[C_d]		*/ 0x40,
    /* RHcode[C_a]		*/ 0x1f,
    /* RHcode[C_a_breve]	*/ 0x07,
    /* RHcode[C_a_circumflex]	*/ 0x07,
	/* skipped 		*/ 0x00,
    /* RHcode[C_e]		*/ 0x17,
    /* RHcode[C_i]		*/ 0x07,
    /* RHcode[C_e_circumflex]	*/ 0x07,
    /* RHcode[C_o]		*/ 0x37,
    /* RHcode[C_u]		*/ 0x27,
    /* RHcode[C_o_circumflex]	*/ 0x07,
    /* RHcode[C_o_horn]		*/ 0x07,
    /* RHcode[C_u_horn]		*/ 0x07,
    /* RHcode[C_y]		*/ 0x07,
    /* RHcode[CO_ACUTE]		*/ 0x00,
    /* RHcode[CO_GRAVE]		*/ 0x00,
    /* RHcode[CO_HOOK_ABOVE]	*/ 0x00,
    /* RHcode[CO_TILDE]		*/ 0x00,
    /* RHcode[CO_DOT_BELOW]	*/ 0x00,
    /* RHcode[CO_BREVE]		*/ 0x07,
    /* RHcode[CO_CIRCUMFLEX]	*/ 0x07,
    /* RHcode[CO_HORN]		*/ 0x07,
};


/*********** LHcode **********/
static u_char LHcode[37] = {
    /* LHcode[all others]	*/ 0x00,
    /* LHcode[C_D]		*/ 0x40,
    /* LHcode[C_A]		*/ 0x00,
    /* LHcode[C_A_breve]	*/ 0x00,
    /* LHcode[C_A_circumflex]	*/ 0x00,
	/* skipped 		*/ 0x00,
    /* LHcode[C_E]		*/ 0x00,
    /* LHcode[C_I]		*/ 0x00,
    /* LHcode[C_E_circumflex]	*/ 0x00,
    /* LHcode[C_O]		*/ 0x00,
    /* LHcode[C_U]		*/ 0x00,
    /* LHcode[C_O_circumflex]	*/ 0x00,
    /* LHcode[C_O_horn]		*/ 0x00,
    /* LHcode[C_U_horn]		*/ 0x00,
    /* LHcode[C_Y]		*/ 0x00,
    /* LHcode[C_d]		*/ 0x40,
    /* LHcode[C_a]		*/ 0x00,
    /* LHcode[C_a_breve]	*/ 0x00,
    /* LHcode[C_a_circumflex]	*/ 0x00,
	/* skipped 		*/ 0x00,
    /* LHcode[C_e]		*/ 0x00,
    /* LHcode[C_i]		*/ 0x00,
    /* LHcode[C_e_circumflex]	*/ 0x00,
    /* LHcode[C_o]		*/ 0x00,
    /* LHcode[C_u]		*/ 0x00,
    /* LHcode[C_o_circumflex]	*/ 0x00,
    /* LHcode[C_o_horn]		*/ 0x00,
    /* LHcode[C_u_horn]		*/ 0x00,
    /* LHcode[C_y]		*/ 0x00,
    /* LHcode[CO_ACUTE]		*/ 0x01,
    /* LHcode[CO_GRAVE]		*/ 0x02,
    /* LHcode[CO_HOOK_ABOVE]	*/ 0x03,
    /* LHcode[CO_TILDE]		*/ 0x04,
    /* LHcode[CO_DOT_BELOW]	*/ 0x05,
    /* LHcode[CO_BREVE]		*/ 0x08,
    /* LHcode[CO_CIRCUMFLEX]	*/ 0x10,
    /* LHcode[CO_HORN]		*/ 0x20,
};

/*********** offset **********/
static u_char offset[37] = {
    /* offset[all others]	*/ 0,
    /* offset[C_D]		*/ 4,
    /* offset[C_A]		*/ 0,
    /* offset[C_A_breve]	*/ 0,
    /* offset[C_A_circumflex]	*/ 0,
	/* skipped 		*/ 0,
    /* offset[C_E]		*/ 0,
    /* offset[C_I]		*/ 0,
    /* offset[C_E_circumflex]	*/ 0,
    /* offset[C_O]		*/ 0,
    /* offset[C_U]		*/ 0,
    /* offset[C_O_circumflex]	*/ 0,
    /* offset[C_O_horn]		*/ 0,
    /* offset[C_U_horn]		*/ 0,
    /* offset[C_Y]		*/ 0,
    /* offset[C_d]		*/ 4,
    /* offset[C_a]		*/ 0,
    /* offset[C_a_breve]	*/ 0,
    /* offset[C_a_circumflex]	*/ 0,
	/* skipped 		*/ 0,
    /* offset[C_e]		*/ 0,
    /* offset[C_i]		*/ 0,
    /* offset[C_e_circumflex]	*/ 0,
    /* offset[C_o]		*/ 0,
    /* offset[C_u]		*/ 0,
    /* offset[C_o_circumflex]	*/ 0,
    /* offset[C_o_horn]		*/ 0,
    /* offset[C_u_horn]		*/ 0,
    /* offset[C_y]		*/ 0,
    /* offset[CO_ACUTE]		*/ 0,
    /* offset[CO_GRAVE]		*/ 0,
    /* offset[CO_HOOK_ABOVE]	*/ 0,
    /* offset[CO_TILDE]		*/ 0,
    /* offset[CO_DOT_BELOW]	*/ 0,
    /* offset[CO_BREVE]		*/ 1,
    /* offset[CO_CIRCUMFLEX]	*/ 2,
    /* offset[CO_HORN]		*/ 3,
};


/****** Resultant table *******/
static u_char	table[29][6] = {
    /* 00 */	{ 0, 0, 0, 0, 0, 0 }, /* save a subtraction to get the index */

    /****** upper case *******/
    /* 01 */	{ C_D, 0, 0, 0, 0, 0},
    /* 02 */	{ C_A, C_A_acute, C_A_grave, C_A_hook_above, C_A_tilde, C_A_dot_below },
    /* 03 */	{ C_A_breve, C_A_breve_acute, C_A_breve_grave, C_A_breve_hook_above, C_A_breve_tilde, C_A_breve_dot_below },
    /* 04 */	{ C_A_circumflex, C_A_circumflex_acute, C_A_circumflex_grave, C_A_circumflex_hook_above, C_A_circumflex_tilde, C_A_circumflex_dot_below },
    /* 05 */	{ C_D_bar, 0, 0, 0, 0, 0},
    /* 06 */	{ C_E, C_E_acute, C_E_grave, C_E_hook_above, C_E_tilde, C_E_dot_below },
    /* 07 */	{ C_I, C_I_acute, C_I_grave, C_I_hook_above, C_I_tilde, C_I_dot_below },
    /* 08 */	{ C_E_circumflex, C_E_circumflex_acute, C_E_circumflex_grave, C_E_circumflex_hook_above, C_E_circumflex_tilde, C_E_circumflex_dot_below },
    /* 09 */	{ C_O, C_O_acute, C_O_grave, C_O_hook_above, C_O_tilde, C_O_dot_below },
    /* 10 */	{ C_U, C_U_acute, C_U_grave, C_U_hook_above, C_U_tilde, C_U_dot_below },
    /* 11 */	{ C_O_circumflex, C_O_circumflex_acute, C_O_circumflex_grave, C_O_circumflex_hook_above, C_O_circumflex_tilde, C_O_circumflex_dot_below },
    /* 12 */	{ C_O_horn, C_O_horn_acute, C_O_horn_grave, C_O_horn_hook_above, C_O_horn_tilde, C_O_horn_dot_below },
    /* 13 */	{ C_U_horn, C_U_horn_acute, C_U_horn_grave, C_U_horn_hook_above, C_U_horn_tilde, C_U_horn_dot_below },
    /* 14 */	{ C_Y, C_Y_acute, C_Y_grave, C_Y_hook_above, C_Y_tilde, C_Y_dot_below },

    /******* lower case ******/
    /* 15 */	{ C_d, 0, 0, 0, 0, 0},
    /* 16 */	{ C_a, C_a_acute, C_a_grave, C_a_hook_above, C_a_tilde, C_a_dot_below },
    /* 17 */	{ C_a_breve, C_a_breve_acute, C_a_breve_grave, C_a_breve_hook_above, C_a_breve_tilde, C_a_breve_dot_below },
    /* 18 */	{ C_a_circumflex, C_a_circumflex_acute, C_a_circumflex_grave, C_a_circumflex_hook_above, C_a_circumflex_tilde, C_a_circumflex_dot_below },
    /* 19 */	{ C_d_bar, 0, 0, 0, 0, 0},
    /* 20 */	{ C_e, C_e_acute, C_e_grave, C_e_hook_above, C_e_tilde, C_e_dot_below },
    /* 21 */	{ C_i, C_i_acute, C_i_grave, C_i_hook_above, C_i_tilde, C_i_dot_below },
    /* 22 */	{ C_e_circumflex, C_e_circumflex_acute, C_e_circumflex_grave, C_e_circumflex_hook_above, C_e_circumflex_tilde, C_e_circumflex_dot_below },
    /* 23 */	{ C_o, C_o_acute, C_o_grave, C_o_hook_above, C_o_tilde, C_o_dot_below },
    /* 24 */	{ C_u, C_u_acute, C_u_grave, C_u_hook_above, C_u_tilde, C_u_dot_below },
    /* 25 */	{ C_o_circumflex, C_o_circumflex_acute, C_o_circumflex_grave, C_o_circumflex_hook_above, C_o_circumflex_tilde, C_o_circumflex_dot_below },
    /* 26 */	{ C_o_horn, C_o_horn_acute, C_o_horn_grave, C_o_horn_hook_above, C_o_horn_tilde, C_o_horn_dot_below },
    /* 27 */	{ C_u_horn, C_u_horn_acute, C_u_horn_grave, C_u_horn_hook_above, C_u_horn_tilde, C_u_horn_dot_below },
    /* 28 */	{ C_y, C_y_acute, C_y_grave, C_y_hook_above, C_y_tilde, C_y_dot_below },

}; /* end of table[][] */


u_char FAR PASCAL
#ifdef ANSI_C
vncompose(Co_Data FAR *Co_data, u_char inchar, int FAR *fl_compose, int FAR *fl_erase)
#else
vncompose(Co_data, inchar, fl_compose, fl_erase)
    Co_Data FAR *Co_data;
    u_char inchar;
    int FAR *fl_compose;
    int FAR *fl_erase;
#endif
{
    u_char	tonemark;


    while (1) {
	switch(C_state) {

/***************************************/
	case CO_ST_LEVEL1:
	    C1 = inchar;
	    I1 = icode[C1];
	    if (I1 == 0 || I1 > 28) { /* won't compose w/ anything, e.g., "n" */
		*fl_compose = 0;	/* not composing */
	    } else { /* C1 might compose, e.g., "e" */
		*fl_compose = 1;
		C_state = CO_ST_LEVEL2;
	    }
	    *fl_erase = 0; /* no erase */
	    return(C1);


/***************************************/
	case CO_ST_LEVEL2:
	    C2 = inchar;
	    I2 = icode[C2];
	    if ((RHcode[I1] & LHcode[I2]) == 0) { /* C1 & C2 won't combine, e.g., en */
		C_state = CO_ST_LEVEL1; /* go back to level 1 and process */
		break;
	    }
	    /* C1 & C2 do combine, e.g., e^ or e' */
	    I1 = I1 + offset[I2];
	    if (LHcode[I2] & 0x38) { /* C2 is a modifier, e.g., e^ */
		C_state = CO_ST_LEVEL3;
		*fl_compose = 1;
	    } else { /* C2 is a tone mark, e.g., e' */
		*fl_compose = 0;
		C_state = CO_ST_LEVEL1;
	    }

	    tonemark = LHcode[I2] & (u_char) 0x07;
	    *fl_erase = 1;
	    return(table[I1][tonemark]);

/***************************************/
	case CO_ST_LEVEL3:
	    C_state = CO_ST_LEVEL1;
	    C3 = inchar;
	    I3 = icode[C3];
	    tonemark = LHcode[I3] & (u_char) 0x07;
	    if (tonemark == 0) { /* C3 is not a tone mark, e.g., e^n */
		break;
	    }
	    /* C3 is a tone mark, e.g., e^' */
	    *fl_compose = 0;
	    *fl_erase = 1;
	    return(table[I1][tonemark]);
	}
    } /* forever */
}


void FAR PASCAL
#ifdef ANSI_C
vncompose_init(Co_Data FAR *Co_data)
#else
vncompose_init(Co_data)
    Co_Data FAR *Co_data;
#endif
{
    int	n;
    u_char *ptr1, *ptr2;

    C_state = CO_ST_LEVEL1;

    /*********** icode **********/
    for (n = sizeof(icode); n; n--) {
	orig_icode[n] = 0;
    }

    orig_icode[C_D]			=  1;
    orig_icode[C_A]			=  2;
    orig_icode[C_A_breve]		=  3;
    orig_icode[C_A_circumflex]	=  4;

    orig_icode[C_E]			=  6;
    orig_icode[C_I]			=  7;
    orig_icode[C_E_circumflex]	=  8;
    orig_icode[C_O]			=  9;
    orig_icode[C_U]			= 10;
    orig_icode[C_O_circumflex]	= 11;
    orig_icode[C_O_horn]		= 12;
    orig_icode[C_U_horn]		= 13;
    orig_icode[C_Y]			= 14;


    orig_icode[C_d]			= 15;
    orig_icode[C_a]			= 16;
    orig_icode[C_a_breve]		= 17;
    orig_icode[C_a_circumflex]	= 18;

    orig_icode[C_e]			= 20;
    orig_icode[C_i]			= 21;
    orig_icode[C_e_circumflex]	= 22;
    orig_icode[C_o]			= 23;
    orig_icode[C_u]			= 24;
    orig_icode[C_o_circumflex]	= 25;
    orig_icode[C_o_horn]		= 26;
    orig_icode[C_u_horn]		= 27;
    orig_icode[C_y]			= 28;

    orig_icode[CO_ACUTE]		= 29;
    orig_icode[CO_GRAVE]		= 30;
    orig_icode[CO_HOOK_ABOVE]	= 31;
    orig_icode[CO_TILDE]		= 32;
    orig_icode[CO_DOT_BELOW]		= 33;

    orig_icode[CO_BREVE]		= 34;
    orig_icode[CO_CIRCUMFLEX]	= 35;
    orig_icode[CO_HORN]		= 36;

    for (n = sizeof(icode); n; n--) {
	icode[n] = orig_icode[n];
    }

    /*********** characters used for diacritics **********/
    Co_data->acute = CO_ACUTE;
    Co_data->grave = CO_GRAVE;
    Co_data->hook_above = CO_HOOK_ABOVE;
    Co_data->tilde = CO_TILDE;
    Co_data->dot_below = CO_DOT_BELOW;
    Co_data->breve = CO_BREVE;
    Co_data->circumflex = CO_CIRCUMFLEX;
    Co_data->horn = CO_HORN;
}


/*
 * vncompose_set() allows a character to be specified for a particular
 * diacritic.  The caller must pass in the Co_data composition structure.
 * It operates by swapping the icode[] index of the characters.
 * If successful, it returns 1.  Else zero.
 *
 */
int FAR PASCAL
#ifdef ANSI_C
vncompose_set(int diacritic, u_char newchar, Co_Data FAR *Co_data)
#else
vncompose_set(diacritic, newchar, Co_data)
    int		diacritic;
    u_char	newchar;
    Co_Data FAR *Co_data;
#endif
{
    u_char	currentchar;
    u_char FAR	*ptr;

    switch(diacritic) {
    case CO_BREVE:
	currentchar = Co_data->breve;
	ptr = (u_char FAR *) &(Co_data->breve);
	break;
    case CO_CIRCUMFLEX:
	currentchar = Co_data->circumflex;
	ptr = (u_char FAR *) &(Co_data->circumflex);
	break;
    case CO_HORN:
	currentchar = Co_data->horn;
	ptr = (u_char FAR *) &(Co_data->horn);
	break;
    case CO_ACUTE:
	currentchar = Co_data->acute;
	ptr = (u_char FAR *) &(Co_data->acute);
	break;
    case CO_GRAVE:
	currentchar = Co_data->grave;
	ptr = (u_char FAR *) &(Co_data->grave);
	break;
    case CO_HOOK_ABOVE:
	currentchar = Co_data->hook_above;
	ptr = (u_char FAR *) &(Co_data->hook_above);
	break;
    case CO_TILDE:
	currentchar = Co_data->tilde;
	ptr = (u_char FAR *) &(Co_data->tilde);
	break;
    case CO_DOT_BELOW:
	currentchar = Co_data->dot_below;
	ptr = (u_char FAR *) &(Co_data->dot_below);
	break;
    default:
	return 0;
    }

    if (newchar != currentchar) {
        icode[newchar] = icode[currentchar];
        icode[currentchar] = orig_icode[currentchar];
        *ptr = newchar;
    }
    return(1);
} /* vncompose_set */