/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at 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 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 (c) 1995 by Sun Microsystems, Inc.
 * All Rights Reserved.
 */


#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <string.h>
#include "kctype.h"
#include "kdefs.h"
#include <errno.h>
#include "ktable.h"
#include "hangulcode.h"

KCHAR c2p();

struct _cv_state {
        char **my_outbuf;
        size_t *my_outbytesleft;
        int invalid;
        int flush_obuf;
        char temp_obuf[5];
        int start_cnt;
        int end_cnt;
        char temp_ibuf[1];
        int ibuf_left;
};

void AddChar (char Char, struct _cv_state *st);
int write_21(KCHAR code_2, struct _cv_state *st);


static void echo_vowel(char*, int*);
static void echo_consonant(char*, int*);
static int _wansung_to_cvc(unsigned short code,
        unsigned char* ci_ret, unsigned char* v_ret, unsigned char* cf_ret);

typedef enum { ASCII, WANSUNG } _conv_desc;


/****  _ I C V _ O P E N  ****/

void* _icv_open()
{
        _conv_desc* cd = (_conv_desc*)malloc(sizeof(_conv_desc));

        if (cd == (_conv_desc*)NULL)
        {
                errno = ENOMEM;
                return((void*)-1);
        }

        *cd = ASCII;

        return((void*)cd);
}  /* end of int _icv_open(). */


/****  _ I C V _ C L O S E  ****/

void _icv_close(_conv_desc* cd)
{
        if (!cd)
                errno = EBADF;
        else
                free((void*)cd);
}  /* end of void _icv_close(_conv_desc*). */


/****  _ I C V _ I C O N V  ****/

size_t _icv_iconv(_conv_desc* state, char** inbuf, size_t* inbufleft,
                        char** outbuf, size_t* outbufleft)
{
        size_t          ret_val = 0;
        unsigned char*  ib;
        unsigned char*  ob;
        unsigned char*  ibtail;
        unsigned char*  obtail;

        if (!state)
        {
                errno = EBADF;
                return((size_t)-1);
        }

        if (!inbuf || !(*inbuf))
        {
                if (*state == WANSUNG)
                {
                        if (outbufleft && *outbufleft >= 1 && outbuf && *outbuf)
                        {
                                **outbuf = SI;
                                (*outbuf)++;
                                (*outbufleft)--;
                        }
                        else
                        {
                                errno = E2BIG;
                                return((size_t)-1);
                        }
                }

                *state = ASCII;
                return((size_t)0);
        }

        ib = (unsigned char*)*inbuf;
        ob = (unsigned char*)*outbuf;
        ibtail = ib + *inbufleft;
        obtail = ob + *outbufleft;

        while (ib < ibtail)
        {
                if (!(*ib & 0x80))              /* 7 bits */
                {
                        if ((obtail - ob) < (*state == WANSUNG ? 2 : 1))
                        {
                                errno = E2BIG;
                                ret_val = (size_t)-1;
                                break;
                        }
                        if (*state == WANSUNG)
                        {
                                *ob++ = SI;
                                *state = ASCII;
                        }
                        *ob++ = *ib++;
                }
                else
                {
                        unsigned char   ci, v, cf;
                        register int    ret, j;
                        int             i;
                        char            c[5];

                        if ((ibtail - ib) < 2)
                        {
                                errno = EINVAL;
                                ret_val = (size_t)-1;
                                break;
                        }

                        ret = _wansung_to_cvc((unsigned short)(*ib) << 8 |
                                (unsigned short)(*(ib + 1)), &ci, &v, &cf);
                        i = 0;
                        if (ret != ILLEGAL_SEQ && ret != FAILED)
                        {
                                c[i] = (char)Y19_32[ci != CVC_FILL ?
                                        ci + 1 : 0] + '@';
                                if (c[i] > '@')
                                        i++;
                                c[i] = (char)Y21_32[v != CVC_FILL ? v +
                                        (short)(v + 1) / 3 + 2 : 1] + '`';
                                if (c[i] > 'a')
                                        echo_vowel(c, &i);
                                c[i] = (char)Y28_32[cf != CVC_FILL ?
                                        cf - 1 : 0] + '@';
                                if (c[i] > '@')
                                        echo_consonant(c, &i);

                                if ((obtail - ob) < (i + (*state == ASCII ?
                                                                1 : 0)))
                                {
                                        errno = E2BIG;
                                        ret_val = (size_t)-1;
                                        break;
                                }
                                if (*state == ASCII)
                                {
                                        *ob++ = SO;
                                        *state = WANSUNG;
                                }
                                for (j = 0; j < i; j++)
                                        *ob++ = c[j];
                        }
                        else
                        {
                                /* Let's assume the code is non-identical. */
                                if (*state == WANSUNG)
                                {
                                        if ((obtail - ob) < 3)
                                        {
                                                errno = E2BIG;
                                                ret_val = (size_t)-1;
                                                break;
                                        }
                                        *ob++ = SI;
                                        *state = ASCII;
                                }
                                else if ((obtail - ob) < 2)
                                {
                                        errno = E2BIG;
                                        ret_val = (size_t)-1;
                                        break;
                                }
                                *ob++ = NON_IDENTICAL;
                                *ob++ = NON_IDENTICAL;
                                ret_val += 2;
                        }
                        ib += 2;
                }
        }

        *inbuf = (char*)ib;
        *inbufleft = ibtail - ib;
        *outbuf = (char*)ob;
        *outbufleft = obtail - ob;

        return(ret_val);
}  /* end of size_t _icv_iconv(_conv_desc*, char**, size_t*, char**, size_t*).*/


/****  E C H O _ V O W E L  ****/

static void echo_vowel(char* c,  int* i)
{
        if (c[*i] == 'm')  /* _|_|- */
        {
                c[(*i)++] = 'l';        /* _|_ */
                c[(*i)++] = 'b';        /* |- */
        }
        else if (c[*i] == 'n')  /* _|_H */
        {
                c[(*i)++] = 'l';        /* _|_ */
                c[(*i)++] = 'c';        /* H */
        }
        else if (c[*i] == 'o')  /* _|_| */
        {
                c[(*i)++] = 'l';        /* _|_ */
                c[(*i)++] = '|';        /* | */
        }
        else if (c[*i] == 't')  /* T-| */
        {
                c[(*i)++] = 's';        /* T */
                c[(*i)++] = 'f';        /* -| */
        }
        else if (c[*i] == 'u')  /* T-|| */
        {
                c[(*i)++] = 's';        /* T */
                c[(*i)++] = 'g';        /* -|| */
        }
        else if (c[*i] == 'v')  /* T| */
        {
                c[(*i)++] = 's';        /* T */
                c[(*i)++] = '|';        /* | */
        }
        else if (c[*i] == '{')  /* _| */
        {
                c[(*i)++] = 'z';        /* __ */
                c[(*i)++] = '|';        /* | */
        }
        else
                (*i)++;
}  /* end of static void echo_vowel(char*, int*). */


/****  E C H O _ C O N S O N A N T  ****/

static void echo_consonant(char* c,  int* i)
{
        if (c[*i] == 'C')  /* gs */
        {
                c[(*i)++] = 'A';        /* g */
                c[(*i)++] = 'U';        /* s */
        }
        else if (c[*i] == 'E')  /* nj */
        {
                c[(*i)++] = 'D';        /* n */
                c[(*i)++] = 'X';        /* j */
        }
        else if (c[*i] == 'F')  /* nh */
        {
                c[(*i)++] = 'D';        /* n */
                c[(*i)++] = '^';        /* h */
        }
        else if (c[*i] == 'J')  /* rg */
        {
                c[(*i)++] = 'I';        /* r */
                c[(*i)++] = 'A';        /* g */
        }
        else if (c[*i] == 'K')  /* rm */
        {
                c[(*i)++] = 'I';        /* r */
                c[(*i)++] = 'Q';        /* m */
        }
        else if (c[*i] == 'L')  /* rb */
        {
                c[(*i)++] = 'I';        /* r */
                c[(*i)++] = 'R';        /* b */
        }
        else if (c[*i] == 'M')  /* rs */
        {
                c[(*i)++] = 'I';        /* r */
                c[(*i)++] = 'U';        /* s */
        }
        else if (c[*i] == 'N')  /* rt */
        {
                c[(*i)++] = 'I';        /* r */
                c[(*i)++] = '\\';       /* t */
        }
        else if (c[*i] == 'O')  /* rp */
        {
                c[(*i)++] = 'I';        /* r */
                c[(*i)++] = ']';        /* p */
        }
        else if (c[*i] == 'P')  /* rh */
        {
                c[(*i)++] = 'I';        /* r */
                c[(*i)++] = '^';        /* h */
        }
        else if (c[*i] == 'T')  /* bs */
        {
                c[(*i)++] = 'R';        /* b */
                c[(*i)++] = 'U';        /* s */
        }
        else
                (*i)++;
}  /* end of static void echo_consonant(char*, int*). */


/**** _ W A N S U N G _ T O _ C V C ****/

static int _wansung_to_cvc(unsigned short code,
        unsigned char* ci_ret, unsigned char* v_ret, unsigned char* cf_ret)
{
        register short          h, i, l;
        short                   ci, v, cf;
        short                   disp;
        long                    cfbit;

        *ci_ret = *v_ret = *cf_ret = CVC_FILL;

        if (code >= 0xB0A1 && code <= 0xC8FE)
        {
                if ((unsigned short)(code & 0xFF) < 0xA1)
                        return(ILLEGAL_SEQ);

                for (h = CI_CNT, l = 0; ; )
                {
                        ci = (l + h) / 2;
                        if (l >= h)
                                break;
                        if (code < cmp_srchtbl[ci][0])
                                h = ci - 1;
                        else if (code < cmp_srchtbl[ci + 1][0])
                                break;
                        else
                                l = ci + 1;
                }

                for (v = 1; ; )
                {
                        if (code < cmp_srchtbl[ci][v])
                        {
                                while (!cmp_srchtbl[ci][--v])
                                        ;
                                break;
                        }
                        else if (v == V_CNT)
                                break;
                        v++;
                }

                disp = code - cmp_srchtbl[ci][v];
                if (((short)(cmp_srchtbl[ci][v] & 0xFF) + disp) > 0xFE)
                        disp -= SKIP;

                for (cfbit = cmp_bitmap[ci][v], i = -1, cf = -1; i < disp; cf++)
                {
                        if (cfbit & 0x01)
                                i++;
                        cfbit >>= 1;
                }

                if (cf == -1)
                        return(FAILED);

                *ci_ret = (unsigned char)ci;
                *v_ret = (unsigned char)v;
                if (cf >= 2)
                        *cf_ret = (unsigned char)cf;
                return(HANGUL);
        }

        /* Chosung-only */
        if ((code >= 0xA4A1 && code <= 0xA4BE) && (X32_19[code - 0xA4A0] != -1))
        {
                *ci_ret = (unsigned char)((X32_19[code - 0xA4A0] << 2) - 0xA0);
                return(HANJA_OR_SYMBOL);
        }
        else if (code >= 0xA4BF && code <= 0xA4D3)  /* Joongsung-only */
        {
                *v_ret = (unsigned char)(code - 0xA4BE);
                return(HANJA_OR_SYMBOL);
        }

        return(ILLEGAL_SEQ);
}  /* end of static int _wansung_to_cvc(unsigned short, unsigned char*,
                                        unsigned char*, unsigned char*). */

struct _cv_state  *
_cv_open()
{
        struct _cv_state *st;

        if ((st = (struct _cv_state *)malloc(sizeof(struct _cv_state))) == NULL)
                return ((void *)-1);

        st->invalid = 0;
        st->flush_obuf = 0;
        st->ibuf_left = 0;
        st->start_cnt = 0;
        st->end_cnt = 0;

        return (st);
}

void
_cv_close(st)
struct _cv_state *st;
{
        free(st);
}


size_t
_cv_enconv(st, inbuf, inbytesleft, outbuf, outbytesleft)
struct _cv_state *st;
char **inbuf;
size_t*inbytesleft;
char **outbuf;
size_t*outbytesleft;
{
        int     c, d;
        KCHAR   code;

        if (inbuf == NULL || *inbuf == NULL) { /* Reset request. */
                st->invalid = 0;
                st->flush_obuf = 0;
                st->ibuf_left = 0;
                st->start_cnt = 0;
                st->end_cnt = 0;
                return (0);
        }

        if (st->flush_obuf) {
                while ((*outbytesleft > 0) && (st->start_cnt < st->end_cnt)) {
                        **outbuf = st->temp_obuf[st->start_cnt];
                        (*outbuf)++;
                        (*outbytesleft)--;
                        (st->start_cnt)++;
                }

                if (st->start_cnt < st->end_cnt) {
                        return(*inbytesleft);
                } else {
                        st->flush_obuf = 0;
                        st->start_cnt = 0;
                        st->end_cnt = 0;
                }
        }

        st->my_outbuf = outbuf;
        st->my_outbytesleft = outbytesleft;

        while (*inbytesleft > 0 && *(st->my_outbytesleft) > 0) {

                if (st->ibuf_left) {
                        c = st->temp_ibuf[0];
                        st->ibuf_left = 0;
                } else {
                        c = (**inbuf)&BYTE_MASK;
                        (*inbuf)++, (*inbytesleft)--;
                }

                if (iskorea1(c)) {/* Completion Code */
                        if ( *inbytesleft <= 0) {
                                st->ibuf_left = 1;
                                st->temp_ibuf[0] = c;
                                return(*inbytesleft);
                        }

                        d = (**inbuf)&BYTE_MASK;
                        (*inbuf)++, (*inbytesleft)--;
                        code = c<<8|d;


                                /* output hangul character */
                        if (iskorea2(code&BYTE_MASK) && !ishanja(c)) {

                                if (ishangul(c)) {
                                        code = c2p(code);
                                        AddChar (0x0e, st);
                                        write_21(code, st);
                                        AddChar (0x0f, st);

                                } else  if (ishaninit(code) || ishanmid(code)) {
                                        AddChar (0x0e, st);
                                        if (ishaninit(code)) {
                                                AddChar(code - 0xa4a0 + 0x40, st);
                                        } else {
                                                code -= 0xa4bf;
                                                code += (code/6) * 2 + 1;
                                                AddChar(code + 0x61, st);
                                        }
                                        AddChar (0x0f, st);

                                /* other case */
                                } else {
                                        AddChar ('?', st);
                                        AddChar ('?', st);
                                        /*AddChar (c);
                                        AddChar (code&BYTE_MASK);*/
                                }

                        } else {
                                AddChar ('?', st);
                                AddChar ('?', st);
                        }

                        if (st->invalid) { /* ran out of outbuf space */
                                st->invalid = 0;
                                return(*inbytesleft);
                        }

                } else {                /* output normal Ascii code */
                        AddChar (c, st);
                        if (st->invalid) {
                                st->invalid = 0;
                                /*(*outbuf)--;
                                (*outbytesleft)++;
                                (*inbuf)--;
                                (*inbytesleft)++;*/
                                return(*inbytesleft);
                        }
                }
        }
        return (*inbytesleft);
}

void
AddChar (Char, st)
char Char;
struct _cv_state *st;
{
        /* no more outbuf space */
        if (*(st->my_outbytesleft) <= 0) {
            st->invalid = 1;
            st->temp_obuf[st->end_cnt] = Char;
            st->end_cnt++;
            st->flush_obuf = 1;
        } else {
            **(st->my_outbuf) = Char;
            (*(st->my_outbuf))++, (*(st->my_outbytesleft))--;
        }
}

#ifdef TEST

/* test case 1 */
char ibuf1[] = {0xbf, 0xc0, 0xbc, 0xbc, 0xc3, 0xa2 , 0x41};
char obuf1[20];

/* test case 2 */
char ibuf2[] = {0xbf, 0xc0, 0xbc, 0xbc, 0xc3};
char ibuf21[] = {0xa2 , 0x41};
char obuf2[20];

/* test case 3 */
char ibuf3[] = {0xbf, 0xc0, 0xbc, 0xbc, 0xc3, 0xa2 , 0x41};
char obuf3[5];

main()
{
        int i;
        struct _cv_state *st;
        size_t oleft, ileft;
        char *ip1 = &ibuf1[0], *op1 = &obuf1[0],
             *ip2 = &ibuf2[0], *ip21 = &ibuf21[0], *op2 = &obuf2[0],
             *ip3 = &ibuf3[0], *op3 = &obuf3[0];

        /****************************** test case 1 *************************/
        ileft = sizeof(ibuf1);
        oleft = sizeof(obuf1);

        st = _cv_open();

        printf("TEST 1\n INPUT BUFFER: ");
        for (i = 0; i < ileft ; i++) {
            printf("%x ", 0xff&ibuf1[i]);
        }
        printf("\n");
        printf("OUTPUT: return value %d ",
                _cv_enconv(st, &ip1, &ileft, &op1, &oleft));
        printf("ileft %d  oleft %d\n", ileft, oleft);
        printf("        flush_obuf %d  ibuf_left %d\n", st->flush_obuf,
                                                        st->ibuf_left);
        printf("OUTPUT BUFFER: ");
        for (i = 0; i < (sizeof(obuf1) - oleft) ; i++) {
            printf("%x ", obuf1[i]);
        }
        printf("\n\n\n");
        _cv_close(st);

        /************************ test case 2 ******************************/
        ileft = sizeof(ibuf2);
        oleft = sizeof(obuf2);

        st = _cv_open();

        printf("TEST 2\nINPUT BUFFER: ");
        for (i = 0; i < ileft ; i++) {
            printf("%x ", 0xff&ibuf2[i]);
        }
        printf("\n");
        printf("OUTPUT: return value %d ",
                _cv_enconv(st, &ip2, &ileft, &op2, &oleft));
        printf("ileft %d  oleft %d\n", ileft, oleft);
        printf("        flush_obuf %d  ibuf_left %d\n", st->flush_obuf,
                                                        st->ibuf_left);
        printf("OUTPUT BUFFER: ");
        for (i = 0; i < (sizeof(obuf2) - oleft) ; i++) {
            printf("%x ", obuf2[i]);
        }
        printf("\n\n");

        ileft = sizeof(ibuf21);
        oleft = sizeof(obuf2);
        op2 = &obuf2[0];
        printf("INPUT BUFFER: ");
        for (i = 0; i < ileft ; i++) {
            printf("%x ", 0xff&ibuf21[i]);
        }
        printf("\n");
        printf("OUTPUT: return value %d ",
                _cv_enconv(st, &ip21, &ileft, &op2, &oleft));
        printf("ileft %d  oleft %d\n", ileft, oleft);
        printf("        flush_obuf %d  ibuf_left %d\n", st->flush_obuf,
                                                        st->ibuf_left);
        printf("OUTPUT BUFFER: ");
        for (i = 0; i < (sizeof(obuf2) - oleft) ; i++) {
            printf("%x ", obuf2[i]);
        }
        printf("\n\n\n");
        _cv_close(st);

        /************************ test case 3 ******************************/
        ileft = sizeof(ibuf3);
        oleft = sizeof(obuf3);

        st = _cv_open();

        printf("TEST 3\nINPUT BUFFER: ");
        for (i = 0; i < ileft ; i++) {
            printf("%x ", 0xff&ibuf3[i]);
        }
        printf("\n");
        printf("OUTPUT: return value %d ",
                _cv_enconv(st, &ip3, &ileft, &op3, &oleft));
        printf("ileft %d  oleft %d\n", ileft, oleft);
        printf("        flush_obuf %d  ibuf_left %d\n", st->flush_obuf,
                                                        st->ibuf_left);
        printf("        strat_cnt %d   end_cnt %d\n", st->start_cnt,
                                                        st->end_cnt);
        printf("OUTPUT BUFFER: ");
        for (i = 0; i < (sizeof(obuf3) - oleft) ; i++) {
            printf("%x ", obuf3[i]);
        }
        printf("\n\n");

        op3 = &obuf3[0];
        oleft = sizeof(obuf3);
        printf("OUTPUT: return value %d ",
                _cv_enconv(st, &ip3, &ileft, &op3, &oleft));
        printf("ileft %d  oleft %d\n", ileft, oleft);
        printf("        flush_obuf %d  ibuf_left %d\n", st->flush_obuf,
                                                        st->ibuf_left);
        printf("        strat_cnt %d   end_cnt %d\n", st->start_cnt,
                                                        st->end_cnt);
        printf("OUTPUT BUFFER: ");
        for (i = 0; i < (sizeof(obuf3) - oleft) ; i++) {
            printf("%x ", obuf3[i]);
        }
        printf("\n\n");

        op3 = &obuf3[0];
        oleft = sizeof(obuf3);
        printf("OUTPUT: return value %d ",
                _cv_enconv(st, &ip3, &ileft, &op3, &oleft));
        printf("ileft %d  oleft %d\n", ileft, oleft);
        printf("        flush_obuf %d  ibuf_left %d\n", st->flush_obuf,
                                                        st->ibuf_left);
        printf("        strat_cnt %d   end_cnt %d\n", st->start_cnt,
                                                        st->end_cnt);
        printf("OUTPUT BUFFER: ");
        for (i = 0; i < (sizeof(obuf3) - oleft) ; i++) {
            printf("%x ", obuf3[i]);
        }
        printf("\n\n\n");
        _cv_close(st);
}

/* expected output

TEST 1
 INPUT BUFFER: bf c0 bc bc c3 a2 41
OUTPUT: return value 0 ileft 0  oleft 6
        flush_obuf 0  ibuf_left 0
OUTPUT BUFFER: e 57 6c f e 55 67 f e 5a 62 57 f 41


TEST 2
INPUT BUFFER: bf c0 bc bc c3
OUTPUT: return value 0 ileft 0  oleft 12
        flush_obuf 0  ibuf_left 1
OUTPUT BUFFER: e 57 6c f e 55 67 f

INPUT BUFFER: a2 41
OUTPUT: return value 0 ileft 0  oleft 14
        flush_obuf 0  ibuf_left 0
OUTPUT BUFFER: e 5a 62 57 f 41


TEST 3
INPUT BUFFER: bf c0 bc bc c3 a2 41
OUTPUT: return value 3 ileft 3  oleft 0
        flush_obuf 1  ibuf_left 0
        strat_cnt 0   end_cnt 3
OUTPUT BUFFER: e 57 6c f e

OUTPUT: return value 1 ileft 1  oleft 0
        flush_obuf 1  ibuf_left 0
        strat_cnt 0   end_cnt 3
OUTPUT BUFFER: 55 67 f e 5a

OUTPUT: return value 0 ileft 0  oleft 1
        flush_obuf 0  ibuf_left 0
        strat_cnt 0   end_cnt 0
OUTPUT BUFFER: 62 57 f 41

*/
#endif /* TEST */