/* $NetBSD: citrus_viqr.c,v 1.5 2011/11/19 18:20:13 tnozaki Exp $ */

/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c)2006 Citrus Project,
 * 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/cdefs.h>
#include <sys/queue.h>
#include <sys/types.h>

#include <assert.h>
#include <errno.h>
#include <limits.h>
#include <stddef.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <wchar.h>

#include "citrus_namespace.h"
#include "citrus_types.h"
#include "citrus_bcs.h"
#include "citrus_module.h"
#include "citrus_stdenc.h"
#include "citrus_viqr.h"

#define ESCAPE  '\\'

/*
 * this table generated from RFC 1456.
 */
static const char *mnemonic_rfc1456[0x100] = {
  NULL , NULL , "A(?", NULL , NULL , "A(~", "A^~", NULL ,
  NULL , NULL , NULL , NULL , NULL , NULL , NULL , NULL ,
  NULL , NULL , NULL , NULL , "Y?" , NULL , NULL , NULL ,
  NULL , "Y~" , NULL , NULL , NULL , NULL , "Y." , NULL ,
  NULL , NULL , NULL , NULL , NULL , NULL , NULL , NULL ,
  NULL , NULL , NULL , NULL , NULL , NULL , NULL , NULL ,
  NULL , NULL , NULL , NULL , NULL , NULL , NULL , NULL ,
  NULL , NULL , NULL , NULL , NULL , NULL , NULL , NULL ,
  NULL , NULL , NULL , NULL , NULL , NULL , NULL , NULL ,
  NULL , NULL , NULL , NULL , NULL , NULL , NULL , NULL ,
  NULL , NULL , NULL , NULL , NULL , NULL , NULL , NULL ,
  NULL , NULL , NULL , NULL , NULL , NULL , NULL , NULL ,
  NULL , NULL , NULL , NULL , NULL , NULL , NULL , NULL ,
  NULL , NULL , NULL , NULL , NULL , NULL , NULL , NULL ,
  NULL , NULL , NULL , NULL , NULL , NULL , NULL , NULL ,
  NULL , NULL , NULL , NULL , NULL , NULL , NULL , NULL ,
  "A." , "A('", "A(`", "A(.", "A^'", "A^`", "A^?", "A^.",
  "E~" , "E." , "E^'", "E^`", "E^?", "E^~", "E^.", "O^'",
  "O^`", "O^?", "O^~", "O^.", "O+.", "O+'", "O+`", "O+?",
  "I." , "O?" , "O." , "I?" , "U?" , "U~" , "U." , "Y`" ,
  "O~" , "a('", "a(`", "a(.", "a^'", "a^`", "a^?", "a^.",
  "e~" , "e." , "e^'", "e^`", "e^?", "e^~", "e^.", "o^'",
  "o^`", "o^?", "o^~", "O+~", "O+" , "o^.", "o+`", "o+?",
  "i." , "U+.", "U+'", "U+`", "U+?", "o+" , "o+'", "U+" ,
  "A`" , "A'" , "A^" , "A~" , "A?" , "A(" , "a(?", "a(~",
  "E`" , "E'" , "E^" , "E?" , "I`" , "I'" , "I~" , "y`" ,
  "DD" , "u+'", "O`" , "O'" , "O^" , "a." , "y?" , "u+`",
  "u+?", "U`" , "U'" , "y~" , "y." , "Y'" , "o+~", "u+" ,
  "a`" , "a'" , "a^" , "a~" , "a?" , "a(" , "u+~", "a^~",
  "e`" , "e'" , "e^" , "e?" , "i`" , "i'" , "i~" , "i?" ,
  "dd" , "u+.", "o`" , "o'" , "o^" , "o~" , "o?" , "o." ,
  "u." , "u`" , "u'" , "u~" , "u?" , "y'" , "o+.", "U+~",
};

typedef struct {
        const char      *name;
        wchar_t          value;
} mnemonic_def_t;

static const mnemonic_def_t mnemonic_ext[] = {
/* add extra mnemonic here (should be sorted by wchar_t order). */
};
static const size_t mnemonic_ext_size =
        sizeof(mnemonic_ext) / sizeof(mnemonic_def_t);

static const char *
mnemonic_ext_find(wchar_t wc, const mnemonic_def_t *head, size_t n)
{
        const mnemonic_def_t *mid;

        for (; n > 0; n >>= 1) {
                mid = head + (n >> 1);
                if (mid->value == wc)
                        return (mid->name);
                else if (mid->value < wc) {
                        head = mid + 1;
                        --n;
                }
        }
        return (NULL);
}

struct mnemonic_t;
typedef TAILQ_HEAD(mnemonic_list_t, mnemonic_t) mnemonic_list_t;
typedef struct mnemonic_t {
        TAILQ_ENTRY(mnemonic_t)  entry;
        struct mnemonic_t       *parent;
        mnemonic_list_t          child;
        wchar_t                  value;
        int                      ascii;
} mnemonic_t;

static mnemonic_t *
mnemonic_list_find(mnemonic_list_t *ml, int ch)
{
        mnemonic_t *m;

        TAILQ_FOREACH(m, ml, entry) {
                if (m->ascii == ch)
                        return (m);
        }

        return (NULL);
}

static mnemonic_t *
mnemonic_create(mnemonic_t *parent, int ascii, wchar_t value)
{
        mnemonic_t *m;

        m = malloc(sizeof(*m));
        if (m != NULL) {
                m->parent = parent;
                m->ascii = ascii;
                m->value = value;
                TAILQ_INIT(&m->child);
        }

        return (m);
}

static int
mnemonic_append_child(mnemonic_t *m, const char *s,
    wchar_t value, wchar_t invalid)
{
        mnemonic_t *m0;
        int ch;

        ch = (unsigned char)*s++;
        if (ch == '\0')
                return (EINVAL);
        m0 = mnemonic_list_find(&m->child, ch);
        if (m0 == NULL) {
                m0 = mnemonic_create(m, ch, (wchar_t)ch);
                if (m0 == NULL)
                        return (ENOMEM);
                TAILQ_INSERT_TAIL(&m->child, m0, entry);
        }
        m = m0;
        for (m0 = NULL; (ch = (unsigned char)*s) != '\0'; ++s) {
                m0 = mnemonic_list_find(&m->child, ch);
                if (m0 == NULL) {
                        m0 = mnemonic_create(m, ch, invalid);
                        if (m0 == NULL)
                                return (ENOMEM);
                        TAILQ_INSERT_TAIL(&m->child, m0, entry);
                }
                m = m0;
        }
        if (m0 == NULL)
                return (EINVAL);
        m0->value = value;

        return (0);
}

static void
mnemonic_destroy(mnemonic_t *m)
{
        mnemonic_t *m0, *n;

        TAILQ_FOREACH_SAFE(m0, &m->child, entry, n)
                mnemonic_destroy(m0);
        free(m);
}

typedef struct {
        mnemonic_t      *mroot;
        wchar_t          invalid;
        size_t           mb_cur_max;
} _VIQREncodingInfo;

typedef struct {
        int      chlen;
        char     ch[MB_LEN_MAX];
} _VIQRState;

#define _CEI_TO_EI(_cei_)               (&(_cei_)->ei)
#define _CEI_TO_STATE(_cei_, _func_)    (_cei_)->states.s_##_func_

#define _FUNCNAME(m)                    _citrus_VIQR_##m
#define _ENCODING_INFO                  _VIQREncodingInfo
#define _ENCODING_STATE                 _VIQRState
#define _ENCODING_MB_CUR_MAX(_ei_)      (_ei_)->mb_cur_max
#define _ENCODING_IS_STATE_DEPENDENT            1
#define _STATE_NEEDS_EXPLICIT_INIT(_ps_)        0

static __inline void
/*ARGSUSED*/
_citrus_VIQR_init_state(_VIQREncodingInfo * __restrict ei __unused,
    _VIQRState * __restrict psenc)
{

        psenc->chlen = 0;
}

#if 0
static __inline void
/*ARGSUSED*/
_citrus_VIQR_pack_state(_VIQREncodingInfo * __restrict ei __unused,
    void *__restrict pspriv, const _VIQRState * __restrict psenc)
{

        memcpy(pspriv, (const void *)psenc, sizeof(*psenc));
}

static __inline void
/*ARGSUSED*/
_citrus_VIQR_unpack_state(_VIQREncodingInfo * __restrict ei __unused,
    _VIQRState * __restrict psenc, const void * __restrict pspriv)
{

        memcpy((void *)psenc, pspriv, sizeof(*psenc));
}
#endif

static int
_citrus_VIQR_mbrtowc_priv(_VIQREncodingInfo * __restrict ei,
    wchar_t * __restrict pwc, char ** __restrict s, size_t n,
    _VIQRState * __restrict psenc, size_t * __restrict nresult)
{
        mnemonic_t *m, *m0;
        char *s0;
        wchar_t wc;
        ssize_t i;
        int ch, escape;

        if (*s == NULL) {
                _citrus_VIQR_init_state(ei, psenc);
                *nresult = (size_t)_ENCODING_IS_STATE_DEPENDENT;
                return (0);
        }
        s0 = *s;

        i = 0;
        m = ei->mroot;
        for (escape = 0;;) {
                if (psenc->chlen == i) {
                        if (n-- < 1) {
                                *s = s0;
                                *nresult = (size_t)-2;
                                return (0);
                        }
                        psenc->ch[psenc->chlen++] = *s0++;
                }
                ch = (unsigned char)psenc->ch[i++];
                if (ch == ESCAPE) {
                        if (m != ei->mroot)
                                break;
                        escape = 1;
                        continue;
                }
                if (escape != 0)
                        break;
                m0 = mnemonic_list_find(&m->child, ch);
                if (m0 == NULL)
                        break;
                m = m0;
        }
        while (m != ei->mroot) {
                --i;
                if (m->value != ei->invalid)
                        break;
                m = m->parent;
        }
        if (ch == ESCAPE && m != ei->mroot)
                ++i;
        psenc->chlen -= i;
        memmove(&psenc->ch[0], &psenc->ch[i], psenc->chlen);
        wc = (m == ei->mroot) ? (wchar_t)ch : m->value;
        if (pwc != NULL)
                *pwc = wc;
        *nresult = (size_t)(wc == 0 ? 0 : s0 - *s);
        *s = s0;

        return (0);
}

static int
_citrus_VIQR_wcrtomb_priv(_VIQREncodingInfo * __restrict ei,
    char * __restrict s, size_t n, wchar_t wc,
    _VIQRState * __restrict psenc, size_t * __restrict nresult)
{
        mnemonic_t *m;
        const char *p;
        int ch = 0;

        switch (psenc->chlen) {
        case 0: case 1:
                break;
        default:
                return (EINVAL);
        }
        m = NULL;
        if ((uint32_t)wc <= 0xFF) {
                p = mnemonic_rfc1456[wc & 0xFF];
                if (p != NULL)
                        goto mnemonic_found;
                if (n-- < 1)
                        goto e2big;
                ch = (unsigned int)wc;
                m = ei->mroot;
                if (psenc->chlen > 0) {
                        m = mnemonic_list_find(&m->child, psenc->ch[0]);
                        if (m == NULL)
                                return (EINVAL);
                        psenc->ch[0] = ESCAPE;
                }
                if (mnemonic_list_find(&m->child, ch) == NULL) {
                        psenc->chlen = 0;
                        m = NULL;
                }
                psenc->ch[psenc->chlen++] = ch;
        } else {
                p = mnemonic_ext_find(wc, &mnemonic_ext[0], mnemonic_ext_size);
                if (p == NULL) {
                        *nresult = (size_t)-1;
                        return (EILSEQ);
                } else {
mnemonic_found:
                        psenc->chlen = 0;
                        while (*p != '\0') {
                                if (n-- < 1)
                                        goto e2big;
                                psenc->ch[psenc->chlen++] = *p++;
                        }
                }
        }
        memcpy(s, psenc->ch, psenc->chlen);
        *nresult = psenc->chlen;
        if (m == ei->mroot) {
                psenc->ch[0] = ch;
                psenc->chlen = 1;
        } else
                psenc->chlen = 0;

        return (0);

e2big:
        *nresult = (size_t)-1;
        return (E2BIG);
}

static int
/* ARGSUSED */
_citrus_VIQR_put_state_reset(_VIQREncodingInfo * __restrict ei __unused,
    char * __restrict s __unused, size_t n __unused,
    _VIQRState * __restrict psenc, size_t * __restrict nresult)
{

        switch (psenc->chlen) {
        case 0: case 1:
                break;
        default:
                return (EINVAL);
        }
        *nresult = 0;
        psenc->chlen = 0;

        return (0);
}

static __inline int
/*ARGSUSED*/
_citrus_VIQR_stdenc_wctocs(_VIQREncodingInfo * __restrict ei __unused,
    _csid_t * __restrict csid, _index_t * __restrict idx, wchar_t wc)
{

        *csid = 0;
        *idx = (_index_t)wc;

        return (0);
}

static __inline int
/*ARGSUSED*/
_citrus_VIQR_stdenc_cstowc(_VIQREncodingInfo * __restrict ei __unused,
    wchar_t * __restrict pwc, _csid_t csid, _index_t idx)
{

        if (csid != 0)
                return (EILSEQ);
        *pwc = (wchar_t)idx;

        return (0);
}

static void
_citrus_VIQR_encoding_module_uninit(_VIQREncodingInfo *ei)
{

        mnemonic_destroy(ei->mroot);
}

static int
/*ARGSUSED*/
_citrus_VIQR_encoding_module_init(_VIQREncodingInfo * __restrict ei,
    const void * __restrict var __unused, size_t lenvar __unused)
{
        const char *s;
        size_t i, n;
        int errnum;

        ei->mb_cur_max = 1;
        ei->invalid = (wchar_t)-1;
        ei->mroot = mnemonic_create(NULL, '\0', ei->invalid);
        if (ei->mroot == NULL)
                return (ENOMEM);
        for (i = 0; i < sizeof(mnemonic_rfc1456) / sizeof(const char *); ++i) {
                s = mnemonic_rfc1456[i];
                if (s == NULL)
                        continue;
                n = strlen(s);
                if (ei->mb_cur_max < n)
                        ei->mb_cur_max = n;
                errnum = mnemonic_append_child(ei->mroot,
                    s, (wchar_t)i, ei->invalid);
                if (errnum != 0) {
                        _citrus_VIQR_encoding_module_uninit(ei);
                        return (errnum);
                }
        }
        /* a + 1 < b + 1 here to silence gcc warning about unsigned < 0. */
        for (i = 0; i + 1 < mnemonic_ext_size + 1; ++i) {
                const mnemonic_def_t *p;

                p = &mnemonic_ext[i];
                n = strlen(p->name);
                if (ei->mb_cur_max < n)
                        ei->mb_cur_max = n;
                errnum = mnemonic_append_child(ei->mroot,
                    p->name, p->value, ei->invalid);
                if (errnum != 0) {
                        _citrus_VIQR_encoding_module_uninit(ei);
                        return (errnum);
                }
        }

        return (0);
}

static __inline int
/*ARGSUSED*/
_citrus_VIQR_stdenc_get_state_desc_generic(_VIQREncodingInfo * __restrict ei __unused,
    _VIQRState * __restrict psenc, int * __restrict rstate)
{

        *rstate = (psenc->chlen == 0) ?
            _STDENC_SDGEN_INITIAL :
            _STDENC_SDGEN_INCOMPLETE_CHAR;

        return (0);
}

/* ----------------------------------------------------------------------
 * public interface for stdenc
 */

_CITRUS_STDENC_DECLS(VIQR);
_CITRUS_STDENC_DEF_OPS(VIQR);

#include "citrus_stdenc_template.h"