/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2003, 2005 Ryuichiro Imura
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/iconv.h>

#include "iconv_converter_if.h"

/*
 * "XLAT16" converter
 */

#ifdef MODULE_DEPEND
MODULE_DEPEND(iconv_xlat16, libiconv, 2, 2, 2);
#endif

#define C2I1(c) ((c) & 0x8000 ? ((c) & 0xff) | 0x100 : (c) & 0xff)
#define C2I2(c) ((c) & 0x8000 ? ((c) >> 8) & 0x7f : ((c) >> 8) & 0xff)

/*
 * XLAT16 converter instance
 */
struct iconv_xlat16 {
        KOBJ_FIELDS;
        uint32_t *              d_table[0x200];
        void *                  f_ctp;
        void *                  t_ctp;
        struct iconv_cspair *   d_csp;
};

static int
iconv_xlat16_open(struct iconv_converter_class *dcp,
        struct iconv_cspair *csp, struct iconv_cspair *cspf, void **dpp)
{
        struct iconv_xlat16 *dp;
        uint32_t *headp, **idxp;
        int i;

        dp = (struct iconv_xlat16 *)kobj_create((struct kobj_class*)dcp, M_ICONV, M_WAITOK);
        headp = (uint32_t *)((caddr_t)csp->cp_data + sizeof(dp->d_table));
        idxp = (uint32_t **)csp->cp_data;
        for (i = 0 ; i < 0x200 ; i++) {
                if (*idxp) {
                        dp->d_table[i] = headp;
                        headp += 0x80;
                } else {
                        dp->d_table[i] = NULL;
                }
                idxp++;
        }

        if (strcmp(csp->cp_to, KICONV_WCTYPE_NAME) != 0) {
                if (iconv_open(KICONV_WCTYPE_NAME, csp->cp_from, &dp->f_ctp) != 0)
                        dp->f_ctp = NULL;
                if (iconv_open(KICONV_WCTYPE_NAME, csp->cp_to, &dp->t_ctp) != 0)
                        dp->t_ctp = NULL;
        } else {
                dp->f_ctp = dp->t_ctp = dp;
        }

        dp->d_csp = csp;
        csp->cp_refcount++;
        *dpp = (void*)dp;
        return (0);
}

static int
iconv_xlat16_close(void *data)
{
        struct iconv_xlat16 *dp = data;

        if (dp->f_ctp && dp->f_ctp != data)
                iconv_close(dp->f_ctp);
        if (dp->t_ctp && dp->t_ctp != data)
                iconv_close(dp->t_ctp);
        dp->d_csp->cp_refcount--;
        kobj_delete((struct kobj*)data, M_ICONV);
        return (0);
}

static int
iconv_xlat16_conv(void *d2p, const char **inbuf,
        size_t *inbytesleft, char **outbuf, size_t *outbytesleft,
        int convchar, int casetype)
{
        struct iconv_xlat16 *dp = (struct iconv_xlat16*)d2p;
        const char *src;
        char *dst;
        int nullin, ret = 0;
        size_t in, on, ir, or, inlen;
        uint32_t code;
        u_char u, l;
        uint16_t c1, c2, ctmp;

        if (inbuf == NULL || *inbuf == NULL || outbuf == NULL || *outbuf == NULL)
                return (0);
        ir = in = *inbytesleft;
        or = on = *outbytesleft;
        src = *inbuf;
        dst = *outbuf;

        while(ir > 0 && or > 0) {
                inlen = 0;
                code = 0;

                c1 = ir > 1 ? *(src+1) & 0xff : 0;
                c2 = *src & 0xff;
                ctmp = 0;

                c1 = c2 & 0x80 ? c1 | 0x100 : c1;
                c2 = c2 & 0x80 ? c2 & 0x7f : c2;

                if (ir > 1 && dp->d_table[c1] && dp->d_table[c1][c2]) {
                        /*
                         * inbuf char is a double byte char
                         */
                        inlen = 2;

                        /* toupper,tolower */
                        if (casetype == KICONV_FROM_LOWER && dp->f_ctp)
                                ctmp = towlower(((u_char)*src << 8) | (u_char)*(src + 1),
                                    dp->f_ctp);
                        else if (casetype == KICONV_FROM_UPPER && dp->f_ctp)
                                ctmp = towupper(((u_char)*src << 8) | (u_char)*(src + 1),
                                    dp->f_ctp);
                        if (ctmp) {
                                c1 = C2I1(ctmp);
                                c2 = C2I2(ctmp);
                        }
                }

                if (inlen == 0) {
                        c1 &= 0xff00;
                        if (!dp->d_table[c1]) {
                                ret = -1;
                                break;
                        }
                        /*
                         * inbuf char is a single byte char
                         */
                        inlen = 1;

                        if (casetype & (KICONV_FROM_LOWER|KICONV_FROM_UPPER))
                                code = dp->d_table[c1][c2];

                        if (casetype == KICONV_FROM_LOWER) {
                                if (dp->f_ctp)
                                        ctmp = towlower((u_char)*src, dp->f_ctp);
                                else if (code & XLAT16_HAS_FROM_LOWER_CASE)
                                        ctmp = (u_char)(code >> 16);
                        } else if (casetype == KICONV_FROM_UPPER) {
                                if (dp->f_ctp)
                                        ctmp = towupper((u_char)*src, dp->f_ctp);
                                else if (code & XLAT16_HAS_FROM_UPPER_CASE)
                                        ctmp = (u_char)(code >> 16);
                        }
                        if (ctmp) {
                                c1 = C2I1(ctmp << 8);
                                c2 = C2I2(ctmp << 8);
                        }
                }

                code = dp->d_table[c1][c2];
                if (!code) {
                        ret = -1;
                        break;
                }

                nullin = (code & XLAT16_ACCEPT_NULL_IN) ? 1 : 0;
                if (inlen == 1 && nullin) {
                        /*
                         * XLAT16_ACCEPT_NULL_IN requires inbuf has 2byte
                         */
                        ret = -1;
                        break;
                }

                /*
                 * now start translation
                 */
                u = (u_char)(code >> 8);
                l = (u_char)code;

#ifdef XLAT16_ACCEPT_3BYTE_CHR
                if (code & XLAT16_IS_3BYTE_CHR) {
                        if (or < 3) {
                                ret = -1;
                                break;
                        }
                        *dst++ = u;
                        *dst++ = l;
                        *dst++ = (u_char)(code >> 16);
                        or -= 3;
                } else
#endif
                if (u || code & XLAT16_ACCEPT_NULL_OUT) {
                        if (or < 2) {
                                ret = -1;
                                break;
                        }

                        /* toupper,tolower */
                        if (casetype == KICONV_LOWER && dp->t_ctp) {
                                code = towlower((uint16_t)code, dp->t_ctp);
                                u = (u_char)(code >> 8);
                                l = (u_char)code;
                        }
                        if (casetype == KICONV_UPPER && dp->t_ctp) {
                                code = towupper((uint16_t)code, dp->t_ctp);
                                u = (u_char)(code >> 8);
                                l = (u_char)code;
                        }

                        *dst++ = u;
                        *dst++ = l;
                        or -= 2;
                } else {
                        /* toupper,tolower */
                        if (casetype == KICONV_LOWER) {
                                if (dp->t_ctp)
                                        l = (u_char)towlower(l, dp->t_ctp);
                                else if (code & XLAT16_HAS_LOWER_CASE)
                                        l = (u_char)(code >> 16);
                        }
                        if (casetype == KICONV_UPPER) {
                                if (dp->t_ctp)
                                        l = (u_char)towupper(l, dp->t_ctp);
                                else if (code & XLAT16_HAS_UPPER_CASE)
                                        l = (u_char)(code >> 16);
                        }

                        *dst++ = l;
                        or--;
                }

                if (inlen == 2) {
                        /*
                         * there is a case that inbuf char is a single
                         * byte char while inlen == 2
                         */
                        if ((u_char)*(src+1) == '\0' && !nullin ) {
                                src++;
                                ir--;
                        } else {
                                src += 2;
                                ir -= 2;
                        }
                } else {
                        src++;
                        ir--;
                }

                if (convchar == 1)
                        break;
        }

        *inbuf += in - ir;
        *outbuf += on - or;
        *inbytesleft -= in - ir;
        *outbytesleft -= on - or;
        return (ret);
}

static const char *
iconv_xlat16_name(struct iconv_converter_class *dcp)
{
        return ("xlat16");
}

static int
iconv_xlat16_tolower(void *d2p, int c)
{
        struct iconv_xlat16 *dp = (struct iconv_xlat16*)d2p;
        int c1, c2, out;

        if (c < 0x100) {
                c1 = C2I1(c << 8);
                c2 = C2I2(c << 8);
        } else if (c < 0x10000) {
                c1 = C2I1(c);
                c2 = C2I2(c);
        } else
                return (c);

        if (dp->d_table[c1] && dp->d_table[c1][c2] & XLAT16_HAS_LOWER_CASE) {
                /*return (int)(dp->d_table[c1][c2] & 0xffff);*/
                out = dp->d_table[c1][c2] & 0xffff;
                if ((out & 0xff) == 0)
                        out = (out >> 8) & 0xff;
                return (out);
        } else
                return (c);
}

static int
iconv_xlat16_toupper(void *d2p, int c)
{
        struct iconv_xlat16 *dp = (struct iconv_xlat16*)d2p;
        int c1, c2, out;

        if (c < 0x100) {
                c1 = C2I1(c << 8);
                c2 = C2I2(c << 8);
        } else if (c < 0x10000) {
                c1 = C2I1(c);
                c2 = C2I2(c);
        } else
                return (c);

        if (dp->d_table[c1] && dp->d_table[c1][c2] & XLAT16_HAS_UPPER_CASE) {
                out = dp->d_table[c1][c2] & 0xffff;
                if ((out & 0xff) == 0)
                        out = (out >> 8) & 0xff;
                return (out);
        } else
                return (c);
}

static kobj_method_t iconv_xlat16_methods[] = {
        KOBJMETHOD(iconv_converter_open,        iconv_xlat16_open),
        KOBJMETHOD(iconv_converter_close,       iconv_xlat16_close),
        KOBJMETHOD(iconv_converter_conv,        iconv_xlat16_conv),
#if 0
        KOBJMETHOD(iconv_converter_init,        iconv_xlat16_init),
        KOBJMETHOD(iconv_converter_done,        iconv_xlat16_done),
#endif
        KOBJMETHOD(iconv_converter_name,        iconv_xlat16_name),
        KOBJMETHOD(iconv_converter_tolower,     iconv_xlat16_tolower),
        KOBJMETHOD(iconv_converter_toupper,     iconv_xlat16_toupper),
        {0, 0}
};

KICONV_CONVERTER(xlat16, sizeof(struct iconv_xlat16));