/* $NetBSD: citrus_hz.c,v 1.2 2008/06/14 16:01:07 tnozaki Exp $ */

/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c)2004, 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_hz.h"
#include "citrus_prop.h"

/*
 * wchar_t mapping:
 *
 * CTRL/ASCII   00000000 00000000 00000000 gxxxxxxx
 * GB2312       00000000 00000000 0xxxxxxx gxxxxxxx
 * 94/96*n (~M) 0mmmmmmm 0xxxxxxx 0xxxxxxx gxxxxxxx
 */

#define ESCAPE_CHAR     '~'

typedef enum {
        CTRL = 0, ASCII = 1, GB2312 = 2, CS94 = 3, CS96 = 4
} charset_t;

typedef struct {
        int      start;
        int      end;
        int      width;
} range_t;

static const range_t ranges[] = {
#define RANGE(start, end) { start, end, (end - start) + 1 }
/* CTRL   */ RANGE(0x00, 0x1F),
/* ASCII  */ RANGE(0x20, 0x7F),
/* GB2312 */ RANGE(0x21, 0x7E),
/* CS94   */ RANGE(0x21, 0x7E),
/* CS96   */ RANGE(0x20, 0x7F),
#undef RANGE
};

typedef struct escape_t escape_t;
typedef struct {
        charset_t        charset;
        escape_t        *escape;
        ssize_t          length;
#define ROWCOL_MAX      3
} graphic_t;

typedef TAILQ_HEAD(escape_list, escape_t) escape_list;
struct escape_t {
        TAILQ_ENTRY(escape_t)    entry;
        escape_list             *set;
        graphic_t               *left;
        graphic_t               *right;
        int                      ch;
};

#define GL(escape)      ((escape)->left)
#define GR(escape)      ((escape)->right)
#define SET(escape)     ((escape)->set)
#define ESC(escape)     ((escape)->ch)
#define INIT(escape)    (TAILQ_FIRST(SET(escape)))

static __inline escape_t *
find_escape(escape_list *set, int ch)
{
        escape_t *escape;

        TAILQ_FOREACH(escape, set, entry) {
                if (ESC(escape) == ch)
                        break;
        }

        return (escape);
}

typedef struct {
        escape_list      e0;
        escape_list      e1;
        graphic_t       *ascii;
        graphic_t       *gb2312;
} _HZEncodingInfo;

#define E0SET(ei)       (&(ei)->e0)
#define E1SET(ei)       (&(ei)->e1)
#define INIT0(ei)       (TAILQ_FIRST(E0SET(ei)))
#define INIT1(ei)       (TAILQ_FIRST(E1SET(ei)))

typedef struct {
        escape_t        *inuse;
        int              chlen;
        char             ch[ROWCOL_MAX];
} _HZState;

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

#define _FUNCNAME(m)                    _citrus_HZ_##m
#define _ENCODING_INFO                  _HZEncodingInfo
#define _ENCODING_STATE                 _HZState
#define _ENCODING_MB_CUR_MAX(_ei_)      MB_LEN_MAX
#define _ENCODING_IS_STATE_DEPENDENT            1
#define _STATE_NEEDS_EXPLICIT_INIT(_ps_)        ((_ps_)->inuse == NULL)

static __inline void
_citrus_HZ_init_state(_HZEncodingInfo * __restrict ei,
    _HZState * __restrict psenc)
{

        psenc->chlen = 0;
        psenc->inuse = INIT0(ei);
}

#if 0
static __inline void
/*ARGSUSED*/
_citrus_HZ_pack_state(_HZEncodingInfo * __restrict ei __unused,
    void *__restrict pspriv, const _HZState * __restrict psenc)
{

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

static __inline void
/*ARGSUSED*/
_citrus_HZ_unpack_state(_HZEncodingInfo * __restrict ei __unused,
    _HZState * __restrict psenc, const void * __restrict pspriv)
{

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

static int
_citrus_HZ_mbrtowc_priv(_HZEncodingInfo * __restrict ei,
    wchar_t * __restrict pwc, char ** __restrict s, size_t n,
    _HZState * __restrict psenc, size_t * __restrict nresult)
{
        escape_t *candidate, *init;
        graphic_t *graphic;
        const range_t *range;
        char *s0;
        wchar_t wc;
        int bit, ch, head, len, tail;

        if (*s == NULL) {
                _citrus_HZ_init_state(ei, psenc);
                *nresult = 1;
                return (0);
        }
        s0 = *s;
        if (psenc->chlen < 0 || psenc->inuse == NULL)
                return (EINVAL);

        wc = (wchar_t)0;
        bit = head = tail = 0;
        graphic = NULL;
        for (len = 0; len <= MB_LEN_MAX;) {
                if (psenc->chlen == tail) {
                        if (n-- < 1) {
                                *s = s0;
                                *nresult = (size_t)-2;
                                return (0);
                        }
                        psenc->ch[psenc->chlen++] = *s0++;
                        ++len;
                }
                ch = (unsigned char)psenc->ch[tail++];
                if (tail == 1) {
                        if ((ch & ~0x80) <= 0x1F) {
                                if (psenc->inuse != INIT0(ei))
                                        break;
                                wc = (wchar_t)ch;
                                goto done;
                        }
                        if (ch & 0x80) {
                                graphic = GR(psenc->inuse);
                                bit = 0x80;
                                ch &= ~0x80;
                        } else {
                                graphic = GL(psenc->inuse);
                                if (ch == ESCAPE_CHAR)
                                        continue;
                                bit = 0x0;
                        }
                        if (graphic == NULL)
                                break;
                } else if (tail == 2 && psenc->ch[0] == ESCAPE_CHAR) {
                        if (tail < psenc->chlen)
                                return (EINVAL);
                        if (ch == ESCAPE_CHAR) {
                                ++head;
                        } else if (ch == '\n') {
                                if (psenc->inuse != INIT0(ei))
                                        break;
                                tail = psenc->chlen = 0;
                                continue;
                        } else {
                                candidate = NULL;
                                init = INIT0(ei);
                                if (psenc->inuse == init) {
                                        init = INIT1(ei);
                                } else if (INIT(psenc->inuse) == init) {
                                        if (ESC(init) != ch)
                                                break;
                                        candidate = init;
                                }
                                if (candidate == NULL) {
                                        candidate = find_escape(
                                            SET(psenc->inuse), ch);
                                        if (candidate == NULL) {
                                                if (init == NULL ||
                                                    ESC(init) != ch)
                                                        break;
                                                candidate = init;
                                        }
                                }
                                psenc->inuse = candidate;
                                tail = psenc->chlen = 0;
                                continue;
                        }
                } else if (ch & 0x80) {
                        if (graphic != GR(psenc->inuse))
                                break;
                        ch &= ~0x80;
                } else {
                        if (graphic != GL(psenc->inuse))
                                break;
                }
                range = &ranges[(size_t)graphic->charset];
                if (range->start > ch || range->end < ch)
                        break;
                wc <<= 8;
                wc |= ch;
                if (graphic->length == (tail - head)) {
                        if (graphic->charset > GB2312)
                                bit |= ESC(psenc->inuse) << 24;
                        wc |= bit;
                        goto done;
                }
        }
        *nresult = (size_t)-1;
        return (EILSEQ);
done:
        if (tail < psenc->chlen)
                return (EINVAL);
        *s = s0;
        if (pwc != NULL)
                *pwc = wc;
        psenc->chlen = 0;
        *nresult = (wc == 0) ? 0 : len;

        return (0);
}

static int
_citrus_HZ_wcrtomb_priv(_HZEncodingInfo * __restrict ei,
    char * __restrict s, size_t n, wchar_t wc,
    _HZState * __restrict psenc, size_t * __restrict nresult)
{
        escape_t *candidate, *init;
        graphic_t *graphic;
        const range_t *range;
        size_t len;
        int bit, ch;

        if (psenc->chlen != 0 || psenc->inuse == NULL)
                return (EINVAL);
        if (wc & 0x80) {
                bit = 0x80;
                wc &= ~0x80;
        } else {
                bit = 0x0;
        }
        if ((uint32_t)wc <= 0x1F) {
                candidate = INIT0(ei);
                graphic = (bit == 0) ? candidate->left : candidate->right;
                if (graphic == NULL)
                        goto ilseq;
                range = &ranges[(size_t)CTRL];
                len = 1;
        } else if ((uint32_t)wc <= 0x7F) {
                graphic = ei->ascii;
                if (graphic == NULL)
                        goto ilseq;
                candidate = graphic->escape;
                range = &ranges[(size_t)graphic->charset];
                len = graphic->length;
        } else if ((uint32_t)wc <= 0x7F7F) {
                graphic = ei->gb2312;
                if (graphic == NULL)
                        goto ilseq;
                candidate = graphic->escape;
                range = &ranges[(size_t)graphic->charset];
                len = graphic->length;
        } else {
                ch = (wc >> 24) & 0xFF;
                candidate = find_escape(E0SET(ei), ch);
                if (candidate == NULL) {
                        candidate = find_escape(E1SET(ei), ch);
                        if (candidate == NULL)
                                goto ilseq;
                }
                wc &= ~0xFF000000;
                graphic = (bit == 0) ? candidate->left : candidate->right;
                if (graphic == NULL)
                        goto ilseq;
                range = &ranges[(size_t)graphic->charset];
                len = graphic->length;
        }
        if (psenc->inuse != candidate) {
                init = INIT0(ei);
                if (SET(psenc->inuse) == SET(candidate)) {
                        if (INIT(psenc->inuse) != init ||
                            psenc->inuse == init || candidate == init)
                                init = NULL;
                } else if (candidate == (init = INIT(candidate))) {
                        init = NULL;
                }
                if (init != NULL) {
                        if (n < 2)
                                return (E2BIG);
                        n -= 2;
                        psenc->ch[psenc->chlen++] = ESCAPE_CHAR;
                        psenc->ch[psenc->chlen++] = ESC(init);
                }
                if (n < 2)
                        return (E2BIG);
                n -= 2;
                psenc->ch[psenc->chlen++] = ESCAPE_CHAR;
                psenc->ch[psenc->chlen++] = ESC(candidate);
                psenc->inuse = candidate;
        }
        if (n < len)
                return (E2BIG);
        while (len-- > 0) {
                ch = (wc >> (len * 8)) & 0xFF;
                if (range->start > ch || range->end < ch)
                        goto ilseq;
                psenc->ch[psenc->chlen++] = ch | bit;
        }
        memcpy(s, psenc->ch, psenc->chlen);
        *nresult = psenc->chlen;
        psenc->chlen = 0;

        return (0);

ilseq:
        *nresult = (size_t)-1;
        return (EILSEQ);
}

static __inline int
_citrus_HZ_put_state_reset(_HZEncodingInfo * __restrict ei,
    char * __restrict s, size_t n, _HZState * __restrict psenc,
    size_t * __restrict nresult)
{
        escape_t *candidate;

        if (psenc->chlen != 0 || psenc->inuse == NULL)
                return (EINVAL);
        candidate = INIT0(ei);
        if (psenc->inuse != candidate) {
                if (n < 2)
                        return (E2BIG);
                n -= 2;
                psenc->ch[psenc->chlen++] = ESCAPE_CHAR;
                psenc->ch[psenc->chlen++] = ESC(candidate);
        }
        if (n < 1)
                return (E2BIG);
        if (psenc->chlen > 0)
                memcpy(s, psenc->ch, psenc->chlen);
        *nresult = psenc->chlen;
        _citrus_HZ_init_state(ei, psenc);

        return (0);
}

static __inline int
_citrus_HZ_stdenc_get_state_desc_generic(_HZEncodingInfo * __restrict ei,
    _HZState * __restrict psenc, int * __restrict rstate)
{

        if (psenc->chlen < 0 || psenc->inuse == NULL)
                return (EINVAL);
        *rstate = (psenc->chlen == 0)
            ? ((psenc->inuse == INIT0(ei))
                ? _STDENC_SDGEN_INITIAL
                : _STDENC_SDGEN_STABLE)
            : ((psenc->ch[0] == ESCAPE_CHAR)
                ? _STDENC_SDGEN_INCOMPLETE_SHIFT
                : _STDENC_SDGEN_INCOMPLETE_CHAR);

        return (0);
}

static __inline int
/*ARGSUSED*/
_citrus_HZ_stdenc_wctocs(_HZEncodingInfo * __restrict ei __unused,
    _csid_t * __restrict csid, _index_t * __restrict idx, wchar_t wc)
{
        int bit;

        if (wc & 0x80) {
                bit = 0x80;
                wc &= ~0x80;
        } else
                bit = 0x0;
        if ((uint32_t)wc <= 0x7F) {
                *csid = (_csid_t)bit;
                *idx = (_index_t)wc;
        } else if ((uint32_t)wc <= 0x7F7F) {
                *csid = (_csid_t)(bit | 0x8000);
                *idx = (_index_t)wc;
        } else {
                *csid = (_index_t)(wc & ~0x00FFFF7F);
                *idx = (_csid_t)(wc & 0x00FFFF7F);
        }

        return (0);
}

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

        *wc = (wchar_t)idx;
        switch (csid) {
        case 0x80:
        case 0x8080:
                *wc |= (wchar_t)0x80;
                /*FALLTHROUGH*/
        case 0x0:
        case 0x8000:
                break;
        default:
                *wc |= (wchar_t)csid;
        }

        return (0);
}

static void
_citrus_HZ_encoding_module_uninit(_HZEncodingInfo *ei)
{
        escape_t *escape;

        while ((escape = TAILQ_FIRST(E0SET(ei))) != NULL) {
                TAILQ_REMOVE(E0SET(ei), escape, entry);
                free(GL(escape));
                free(GR(escape));
                free(escape);
        }
        while ((escape = TAILQ_FIRST(E1SET(ei))) != NULL) {
                TAILQ_REMOVE(E1SET(ei), escape, entry);
                free(GL(escape));
                free(GR(escape));
                free(escape);
        }
}

static int
_citrus_HZ_parse_char(void *context, const char *name __unused, const char *s)
{
        escape_t *escape;
        void **p;

        p = (void **)context;
        escape = (escape_t *)p[0];
        if (escape->ch != '\0')
                return (EINVAL);
        escape->ch = *s++;
        if (escape->ch == ESCAPE_CHAR || *s != '\0')
                return (EINVAL);

        return (0);
}

static int
_citrus_HZ_parse_graphic(void *context, const char *name, const char *s)
{
        _HZEncodingInfo *ei;
        escape_t *escape;
        graphic_t *graphic;
        void **p;

        p = (void **)context;
        escape = (escape_t *)p[0];
        ei = (_HZEncodingInfo *)p[1];
        graphic = calloc(1, sizeof(*graphic));
        if (graphic == NULL)
                return (ENOMEM);
        if (strcmp("GL", name) == 0) {
                if (GL(escape) != NULL)
                        goto release;
                GL(escape) = graphic;
        } else if (strcmp("GR", name) == 0) {
                if (GR(escape) != NULL)
                        goto release;
                GR(escape) = graphic;
        } else {
release:
                free(graphic);
                return (EINVAL);
        }
        graphic->escape = escape;
        if (_bcs_strncasecmp("ASCII", s, 5) == 0) {
                if (s[5] != '\0')
                        return (EINVAL);
                graphic->charset = ASCII;
                graphic->length = 1;
                ei->ascii = graphic;
                return (0);
        } else if (_bcs_strncasecmp("GB2312", s, 6) == 0) {
                if (s[6] != '\0')
                        return (EINVAL);
                graphic->charset = GB2312;
                graphic->length = 2;
                ei->gb2312 = graphic;
                return (0);
        } else if (strncmp("94*", s, 3) == 0)
                graphic->charset = CS94;
        else if (strncmp("96*", s, 3) == 0)
                graphic->charset = CS96;
        else
                return (EINVAL);
        s += 3;
        switch(*s) {
        case '1': case '2': case '3':
                graphic->length = (size_t)(*s - '0');
                if (*++s == '\0')
                        break;
        /*FALLTHROUGH*/
        default:
                return (EINVAL);
        }
        return (0);
}

static const _citrus_prop_hint_t escape_hints[] = {
_CITRUS_PROP_HINT_STR("CH", &_citrus_HZ_parse_char),
_CITRUS_PROP_HINT_STR("GL", &_citrus_HZ_parse_graphic),
_CITRUS_PROP_HINT_STR("GR", &_citrus_HZ_parse_graphic),
_CITRUS_PROP_HINT_END
};

static int
_citrus_HZ_parse_escape(void *context, const char *name, const char *s)
{
        _HZEncodingInfo *ei;
        escape_t *escape;
        void *p[2];

        ei = (_HZEncodingInfo *)context;
        escape = calloc(1, sizeof(*escape));
        if (escape == NULL)
                return (EINVAL);
        if (strcmp("0", name) == 0) {
                escape->set = E0SET(ei);
                TAILQ_INSERT_TAIL(E0SET(ei), escape, entry);
        } else if (strcmp("1", name) == 0) {
                escape->set = E1SET(ei);
                TAILQ_INSERT_TAIL(E1SET(ei), escape, entry);
        } else {
                free(escape);
                return (EINVAL);
        }
        p[0] = (void *)escape;
        p[1] = (void *)ei;
        return (_citrus_prop_parse_variable(
            escape_hints, (void *)&p[0], s, strlen(s)));
}

static const _citrus_prop_hint_t root_hints[] = {
_CITRUS_PROP_HINT_STR("0", &_citrus_HZ_parse_escape),
_CITRUS_PROP_HINT_STR("1", &_citrus_HZ_parse_escape),
_CITRUS_PROP_HINT_END
};

static int
_citrus_HZ_encoding_module_init(_HZEncodingInfo * __restrict ei,
    const void * __restrict var, size_t lenvar)
{
        int errnum;

        memset(ei, 0, sizeof(*ei));
        TAILQ_INIT(E0SET(ei));
        TAILQ_INIT(E1SET(ei));
        errnum = _citrus_prop_parse_variable(
            root_hints, (void *)ei, var, lenvar);
        if (errnum != 0)
                _citrus_HZ_encoding_module_uninit(ei);
        return (errnum);
}

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

_CITRUS_STDENC_DECLS(HZ);
_CITRUS_STDENC_DEF_OPS(HZ);

#include "citrus_stdenc_template.h"