/*-
 * Copyright (c)2003 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 "dcmtk/config/osconfig.h"
#include "citrus_iconv_std.h"

#ifdef HAVE_SYS_QUEUE_H
#include <sys/queue.h>
#else
#include "dcmtk/oficonv/queue.h"
#endif


#include <errno.h>
#include <limits.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "citrus_bcs.h"
#include "citrus_types.h"
#include "citrus_module.h"
#include "citrus_region.h"
#include "citrus_mmap.h"
#include "citrus_hash.h"
#include "citrus_iconv.h"
#include "citrus_stdenc.h"
#include "citrus_mapper.h"
#include "citrus_csmapper.h"
#include "citrus_memstream.h"
#include "citrus_esdb.h"

/* ---------------------------------------------------------------------- */

_CITRUS_ICONV_DECLS(iconv_std);
_CITRUS_ICONV_DEF_OPS(iconv_std);


/* ---------------------------------------------------------------------- */

int
_citrus_iconv_std_iconv_getops(struct _citrus_iconv_ops *ops)
{

    memcpy(ops, &_citrus_iconv_std_iconv_ops,
        sizeof(_citrus_iconv_std_iconv_ops));

    return (0);
}

/* ---------------------------------------------------------------------- */

/*
 * convenience routines for stdenc.
 */
static __inline void
save_encoding_state(struct _citrus_iconv_std_encoding *se)
{

    if (se->se_ps)
        memcpy(se->se_pssaved, se->se_ps,
            _citrus_stdenc_get_state_size(se->se_handle));
}

static __inline void
restore_encoding_state(struct _citrus_iconv_std_encoding *se)
{

    if (se->se_ps)
        memcpy(se->se_ps, se->se_pssaved,
            _citrus_stdenc_get_state_size(se->se_handle));
}

static __inline void
init_encoding_state(struct _citrus_iconv_std_encoding *se)
{

    if (se->se_ps)
        _citrus_stdenc_init_state(se->se_handle, se->se_ps);
}

static __inline int
mbtocsx(struct _citrus_iconv_std_encoding *se,
    _citrus_csid_t *csid, _citrus_index_t *idx, char **s, size_t n, size_t *nresult,
    struct iconv_hooks *hooks)
{

    return (_citrus_stdenc_mbtocs(se->se_handle, csid, idx, s, n, se->se_ps,
                  nresult, hooks));
}

static __inline int
cstombx(struct _citrus_iconv_std_encoding *se,
    char *s, size_t n, _citrus_csid_t csid, _citrus_index_t idx, size_t *nresult,
    struct iconv_hooks *hooks)
{

    return (_citrus_stdenc_cstomb(se->se_handle, s, n, csid, idx, se->se_ps,
                  nresult, hooks));
}

static __inline int
wctombx(struct _citrus_iconv_std_encoding *se,
    char *s, size_t n, _citrus_wc_t wc, size_t *nresult,
    struct iconv_hooks *hooks)
{

    return (_citrus_stdenc_wctomb(se->se_handle, s, n, wc, se->se_ps, nresult,
                 hooks));
}

static __inline int
put_state_resetx(struct _citrus_iconv_std_encoding *se, char *s, size_t n,
    size_t *nresult)
{

    return (_citrus_stdenc_put_state_reset(se->se_handle, s, n, se->se_ps, nresult));
}

static __inline int
get_state_desc_gen(struct _citrus_iconv_std_encoding *se, int *rstate)
{
    struct _citrus_stdenc_state_desc ssd;
    int ret;

    ret = _citrus_stdenc_get_state_desc(se->se_handle, se->se_ps,
        _CITRUS_STDENC_SDID_GENERIC, &ssd);
    if (!ret)
        *rstate = ssd.u.generic.state;

    return (ret);
}

/*
 * init encoding context
 */
static int
init_encoding(struct _citrus_iconv_std_encoding *se, struct _citrus_stdenc *cs,
    void *ps1, void *ps2)
{
    int ret = -1;

    se->se_handle = cs;
    se->se_ps = ps1;
    se->se_pssaved = ps2;

    if (se->se_ps)
        ret = _citrus_stdenc_init_state(cs, se->se_ps);
    if (!ret && se->se_pssaved)
        ret = _citrus_stdenc_init_state(cs, se->se_pssaved);

    return (ret);
}

static int
open_csmapper(struct _citrus_csmapper **rcm, const char *src, const char *dst,
    unsigned long *rnorm)
{
    struct _citrus_csmapper *cm;
    int ret;

    ret = _citrus_csmapper_open(&cm, src, dst, 0, rnorm);
    if (ret)
        return (ret);
    if (_citrus_csmapper_get_src_max(cm) != 1 || _citrus_csmapper_get_dst_max(cm) != 1 ||
        _citrus_csmapper_get_state_size(cm) != 0) {
        _citrus_csmapper_close(cm);
        return (EINVAL);
    }

    *rcm = cm;

    return (0);
}

static void
close_dsts(struct _citrus_iconv_std_dst_list *dl)
{
    struct _citrus_iconv_std_dst *sd;

    while ((sd = TAILQ_FIRST(dl)) != NULL) {
        TAILQ_REMOVE(dl, sd, sd_entry);
        _citrus_csmapper_close(sd->sd_mapper);
        free(sd);
    }
}

static int
open_dsts(struct _citrus_iconv_std_dst_list *dl,
    const struct _citrus_esdb_charset *ec, const struct _citrus_esdb *dbdst)
{
    struct _citrus_iconv_std_dst *sd, *sdtmp;
    unsigned long norm;
    int i, ret;

    sd = malloc(sizeof(*sd));
    if (sd == NULL)
        return (errno);

    for (i = 0; i < dbdst->db_num_charsets; i++) {
        ret = open_csmapper(&sd->sd_mapper, ec->ec_csname,
            dbdst->db_charsets[i].ec_csname, &norm);
        if (ret == 0) {
            sd->sd_csid = dbdst->db_charsets[i].ec_csid;
            sd->sd_norm = norm;
            /* insert this mapper by sorted order. */
            TAILQ_FOREACH(sdtmp, dl, sd_entry) {
                if (sdtmp->sd_norm > norm) {
                    TAILQ_INSERT_BEFORE(sdtmp, sd,
                        sd_entry);
                    sd = NULL;
                    break;
                }
            }
            if (sd)
                TAILQ_INSERT_TAIL(dl, sd, sd_entry);
            sd = malloc(sizeof(*sd));
            if (sd == NULL) {
                ret = errno;
                close_dsts(dl);
                return (ret);
            }
        } else if (ret != ENOENT) {
            close_dsts(dl);
            free(sd);
            return (ret);
        }
    }
    free(sd);
    return (0);
}

static void
close_srcs(struct _citrus_iconv_std_src_list *sl)
{
    struct _citrus_iconv_std_src *ss;

    while ((ss = TAILQ_FIRST(sl)) != NULL) {
        TAILQ_REMOVE(sl, ss, ss_entry);
        close_dsts(&ss->ss_dsts);
        free(ss);
    }
}

static int
open_srcs(struct _citrus_iconv_std_src_list *sl,
    const struct _citrus_esdb *dbsrc, const struct _citrus_esdb *dbdst)
{
    struct _citrus_iconv_std_src *ss;
    int count = 0, i, ret;

    ss = malloc(sizeof(*ss));
    if (ss == NULL)
        return (errno);

    TAILQ_INIT(&ss->ss_dsts);

    for (i = 0; i < dbsrc->db_num_charsets; i++) {
        ret = open_dsts(&ss->ss_dsts, &dbsrc->db_charsets[i], dbdst);
        if (ret)
            goto err;
        if (!TAILQ_EMPTY(&ss->ss_dsts)) {
            ss->ss_csid = dbsrc->db_charsets[i].ec_csid;
            TAILQ_INSERT_TAIL(sl, ss, ss_entry);
            ss = malloc(sizeof(*ss));
            if (ss == NULL) {
                ret = errno;
                goto err;
            }
            count++;
            TAILQ_INIT(&ss->ss_dsts);
        }
    }
    free(ss);

    return (count ? 0 : ENOENT);

err:
    free(ss);
    close_srcs(sl);
    return (ret);
}

/* do convert a character */
#define E_NO_CORRESPONDING_CHAR ENOENT /* XXX */
static int
/*ARGSUSED*/
do_conv(const struct _citrus_iconv_std_shared *is,
    _citrus_csid_t *csid, _citrus_index_t *idx)
{
    struct _citrus_iconv_std_dst *sd;
    struct _citrus_iconv_std_src *ss;
    _citrus_index_t tmpidx;
    int ret;

    TAILQ_FOREACH(ss, &is->is_srcs, ss_entry) {
        if (ss->ss_csid == *csid) {
            TAILQ_FOREACH(sd, &ss->ss_dsts, sd_entry) {
                ret = _citrus_csmapper_convert(sd->sd_mapper,
                    &tmpidx, *idx, NULL);
                switch (ret) {
                case _CITRUS_MAPPER_CONVERT_SUCCESS:
                    *csid = sd->sd_csid;
                    *idx = tmpidx;
                    return (0);
                case _CITRUS_MAPPER_CONVERT_NONIDENTICAL:
                    break;
                case _CITRUS_MAPPER_CONVERT_SRC_MORE:
                    /*FALLTHROUGH*/
                case _CITRUS_MAPPER_CONVERT_DST_MORE:
                    /*FALLTHROUGH*/
                case _CITRUS_MAPPER_CONVERT_ILSEQ:
                    return (EILSEQ);
                case _CITRUS_MAPPER_CONVERT_FATAL:
                    return (EINVAL);
                }
            }
            break;
        }
    }

    return (E_NO_CORRESPONDING_CHAR);
}
/* ---------------------------------------------------------------------- */

static int
/*ARGSUSED*/
_citrus_iconv_std_iconv_init_shared(struct _citrus_iconv_shared *ci,
    const char * src, const char * dst)
{
    struct _citrus_esdb esdbdst, esdbsrc;
    struct _citrus_iconv_std_shared *is;
    int ret;

    is = malloc(sizeof(*is));
    if (is == NULL) {
        ret = errno;
        goto err0;
    }
    ret = _citrus_esdb_open(&esdbsrc, src);
    if (ret)
        goto err1;
    ret = _citrus_esdb_open(&esdbdst, dst);
    if (ret)
        goto err2;
    ret = _citrus_stdenc_open(&is->is_src_encoding, esdbsrc.db_encname,
        esdbsrc.db_variable, esdbsrc.db_len_variable);
    if (ret)
        goto err3;
    ret = _citrus_stdenc_open(&is->is_dst_encoding, esdbdst.db_encname,
        esdbdst.db_variable, esdbdst.db_len_variable);
    if (ret)
        goto err4;
    is->is_use_invalid = esdbdst.db_use_invalid;
    is->is_invalid = esdbdst.db_invalid;

    TAILQ_INIT(&is->is_srcs);
    ret = open_srcs(&is->is_srcs, &esdbsrc, &esdbdst);
    if (ret)
        goto err5;

    _citrus_esdb_close(&esdbsrc);
    _citrus_esdb_close(&esdbdst);
    ci->ci_closure = is;

    return (0);

err5:
    _citrus_stdenc_close(is->is_dst_encoding);
err4:
    _citrus_stdenc_close(is->is_src_encoding);
err3:
    _citrus_esdb_close(&esdbdst);
err2:
    _citrus_esdb_close(&esdbsrc);
err1:
    free(is);
err0:
    return (ret);
}

static void
_citrus_iconv_std_iconv_uninit_shared(struct _citrus_iconv_shared *ci)
{
    struct _citrus_iconv_std_shared *is = ci->ci_closure;

    if (is == NULL)
        return;

    _citrus_stdenc_close(is->is_src_encoding);
    _citrus_stdenc_close(is->is_dst_encoding);
    close_srcs(&is->is_srcs);
    free(is);
}

static int
_citrus_iconv_std_iconv_init_context(struct _citrus_iconv *cv)
{
    const struct _citrus_iconv_std_shared *is = cv->cv_shared->ci_closure;
    struct _citrus_iconv_std_context *sc;
    char *ptr;
    size_t sz, szpsdst, szpssrc;

    szpssrc = _citrus_stdenc_get_state_size(is->is_src_encoding);
    szpsdst = _citrus_stdenc_get_state_size(is->is_dst_encoding);

    sz = (szpssrc + szpsdst)*2 + sizeof(struct _citrus_iconv_std_context);
    sc = malloc(sz);
    if (sc == NULL)
        return (errno);

    ptr = (char *)&sc[1];
    if (szpssrc > 0)
        init_encoding(&sc->sc_src_encoding, is->is_src_encoding,
            ptr, ptr+szpssrc);
    else
        init_encoding(&sc->sc_src_encoding, is->is_src_encoding,
            NULL, NULL);
    ptr += szpssrc*2;
    if (szpsdst > 0)
        init_encoding(&sc->sc_dst_encoding, is->is_dst_encoding,
            ptr, ptr+szpsdst);
    else
        init_encoding(&sc->sc_dst_encoding, is->is_dst_encoding,
            NULL, NULL);

    cv->cv_closure = (void *)sc;

    return (0);
}

static void
_citrus_iconv_std_iconv_uninit_context(struct _citrus_iconv *cv)
{

    free(cv->cv_closure);
}

static int
_citrus_iconv_std_iconv_convert(struct _citrus_iconv * cv,
    char * * in, size_t * inbytes,
    char * * out, size_t * outbytes,
    uint32_t flags, size_t * invalids)
{
    const struct _citrus_iconv_std_shared *is = cv->cv_shared->ci_closure;
    struct _citrus_iconv_std_context *sc = cv->cv_closure;
    _citrus_csid_t csid;
    _citrus_index_t idx;
    char *tmpin;
    size_t inval, in_mb_cur_min, szrin, szrout;
    int ret, state = 0;

    inval = 0;
    if (in == NULL || *in == NULL) {
        /* special cases */
        if (out != NULL && *out != NULL) {
            /* init output state and store the shift sequence */
            save_encoding_state(&sc->sc_src_encoding);
            save_encoding_state(&sc->sc_dst_encoding);
            szrout = 0;

            ret = put_state_resetx(&sc->sc_dst_encoding,
                *out, *outbytes, &szrout);
            if (ret)
                goto err;

            if (szrout == (size_t)-2) {
                /* too small to store the character */
                ret = EINVAL;
                goto err;
            }
            *out += szrout;
            *outbytes -= szrout;
        } else
            /* otherwise, discard the shift sequence */
            init_encoding_state(&sc->sc_dst_encoding);
        init_encoding_state(&sc->sc_src_encoding);
        *invalids = 0;
        return (0);
    }

    in_mb_cur_min = _citrus_stdenc_get_mb_cur_min(is->is_src_encoding);

    /* normal case */
    for (;;) {
        if (*inbytes == 0) {
            ret = get_state_desc_gen(&sc->sc_src_encoding, &state);
            if (state == _CITRUS_STDENC_SDGEN_INITIAL ||
                state == _CITRUS_STDENC_SDGEN_STABLE)
                break;
        }

        /* save the encoding states for the error recovery */
        save_encoding_state(&sc->sc_src_encoding);
        save_encoding_state(&sc->sc_dst_encoding);

        /* mb -> csid/index */
        tmpin = *in;
        szrin = szrout = 0;
        ret = mbtocsx(&sc->sc_src_encoding, &csid, &idx, &tmpin,
            *inbytes, &szrin, cv->cv_shared->ci_hooks);

        if (ret != 0 && (ret != EILSEQ ||
            !cv->cv_shared->ci_discard_ilseq)) {
                goto err;
        } else if (ret == EILSEQ) {
                /*
                 * If //IGNORE was specified, we'll just keep crunching
                 * through invalid characters.
                 */
                *in += in_mb_cur_min;
                *inbytes -= in_mb_cur_min;
                restore_encoding_state(&sc->sc_src_encoding);
                restore_encoding_state(&sc->sc_dst_encoding);
                continue;
        }

        if (szrin == (size_t)-2) {
            /* incompleted character */
            ret = get_state_desc_gen(&sc->sc_src_encoding, &state);
            if (ret) {
                ret = EINVAL;
                goto err;
            }
            switch (state) {
            case _CITRUS_STDENC_SDGEN_INITIAL:
            case _CITRUS_STDENC_SDGEN_STABLE:
                /* fetch shift sequences only. */
                goto next;
            }
            ret = EINVAL;
            goto err;
        }
        /* convert the character */
        ret = do_conv(is, &csid, &idx);
        if (ret) {
            if (ret == E_NO_CORRESPONDING_CHAR) {
                /*
                 * GNU iconv returns EILSEQ when no
                 * corresponding character in the output.
                 * Some software depends on this behavior
                 * though this is against POSIX specification.
                 */
                if (cv->cv_shared->ci_ilseq_invalid != 0) {
                        ret = EILSEQ;
                        goto err;
                }
                inval++;
                szrout = 0;
                if ((((flags & _CITRUS_ICONV_F_HIDE_INVALID) == 0) &&
                    !cv->cv_shared->ci_discard_ilseq) &&
                    is->is_use_invalid) {
                    ret = wctombx(&sc->sc_dst_encoding,
                        *out, *outbytes, is->is_invalid,
                        &szrout, cv->cv_shared->ci_hooks);
                    if (ret)
                        goto err;
                }
                goto next;
            } else
                goto err;
        }
        /* csid/index -> mb */
        ret = cstombx(&sc->sc_dst_encoding,
            *out, *outbytes, csid, idx, &szrout,
            cv->cv_shared->ci_hooks);
        if (ret)
            goto err;
next:
        *inbytes -= tmpin-*in; /* szrin is insufficient on \0. */
        *in = tmpin;
        *outbytes -= szrout;
        *out += szrout;
    }
    *invalids = inval;

    return (0);

err:
    restore_encoding_state(&sc->sc_src_encoding);
    restore_encoding_state(&sc->sc_dst_encoding);
    *invalids = inval;

    return (ret);
}