idnkit-1.0-src/lib/converter.c

#ifndef lint
static char *rcsid = "$Id: converter.c,v 1.1 2003/06/04 00:25:51 marka Exp $";
#endif

/*
 * Copyright (c) 2000,2002 Japan Network Information Center.
 * All rights reserved.
 *
 * By using this file, you agree to the terms and conditions set forth bellow.
 *
 *          LICENSE TERMS AND CONDITIONS
 *
 * The following License Terms and Conditions apply, unless a different
 * license is obtained from Japan Network Information Center ("JPNIC"),
 * a Japanese association, Kokusai-Kougyou-Kanda Bldg 6F, 2-3-4 Uchi-Kanda,
 * Chiyoda-ku, Tokyo 101-0047, Japan.
 *
 * 1. Use, Modification and Redistribution (including distribution of any
 *    modified or derived work) in source and/or binary forms is permitted
 *    under this License Terms and Conditions.
 *
 * 2. Redistribution of source code must retain the copyright notices as they
 *    appear in each source code file, this License Terms and Conditions.
 *
 * 3. Redistribution in binary form must reproduce the Copyright Notice,
 *    this License Terms and Conditions, in the documentation and/or other
 *    materials provided with the distribution.  For the purposes of binary
 *    distribution the "Copyright Notice" refers to the following language:
 *    "Copyright (c) 2000-2002 Japan Network Information Center.  All rights reserved."
 *
 * 4. The name of JPNIC may not be used to endorse or promote products
 *    derived from this Software without specific prior written approval of
 *    JPNIC.
 *
 * 5. Disclaimer/Limitation of Liability: THIS SOFTWARE IS PROVIDED BY JPNIC
 *    "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 JPNIC 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 DAMAGES.
 */

#include <config.h>

#include <stddef.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include <errno.h>
#ifndef WITHOUT_ICONV
#include <iconv.h>
#endif

#include <idn/result.h>
#include <idn/assert.h>
#include <idn/logmacro.h>
#include <idn/converter.h>
#include <idn/aliaslist.h>
#include <idn/strhash.h>
#include <idn/debug.h>
#include <idn/ucs4.h>
#include <idn/punycode.h>
#include <idn/race.h>
#include <idn/util.h>

#ifndef IDN_UTF8_ENCODING_NAME
#define IDN_UTF8_ENCODING_NAME "UTF-8"      /* by IANA */
#endif
#ifndef IDN_RACE_ENCODING_NAME
#define IDN_RACE_ENCODING_NAME "RACE"
#endif
#ifndef IDN_AMCACEZ_ENCODING_NAME
#define IDN_AMCACEZ_ENCODING_NAME "AMC-ACE-Z"
#endif
#ifndef IDN_PUNYCODE_ENCODING_NAME
#define IDN_PUNYCODE_ENCODING_NAME "Punycode"
#endif

#define MAX_RECURSE 20

#ifdef WIN32

#define IDNKEY_IDNKIT       "Software\\JPNIC\\IDN"
#define IDNVAL_ALIASFILE    "AliasFile"

#else /* WIN32 */

#ifndef IDN_RESCONF_DIR
#define IDN_RESCONF_DIR     "/etc"
#endif
#define IDN_ALIAS_FILE      IDN_RESCONF_DIR "/idnalias.conf"

#endif /* WIN32 */

typedef struct {
    idn_converter_openproc_t openfromucs4;
    idn_converter_openproc_t opentoucs4;
    idn_converter_convfromucs4proc_t convfromucs4;
    idn_converter_convtoucs4proc_t convtoucs4;
    idn_converter_closeproc_t close;
    int encoding_type;
} converter_ops_t;

struct idn_converter {
    char *local_encoding_name;
    converter_ops_t *ops;
    int flags;
    int opened_convfromucs4;
    int opened_convtoucs4;
    int reference_count;
    void *private_data;
};

static idn__strhash_t encoding_name_hash;
static idn__aliaslist_t encoding_alias_list;

static idn_result_t register_standard_encoding(void);
static idn_result_t roundtrip_check(idn_converter_t ctx,
                    const unsigned long *from,
                    const char *to);

static idn_result_t
       converter_none_open(idn_converter_t ctx, void **privdata);
static idn_result_t
       converter_none_close(idn_converter_t ctx, void *privdata);
static idn_result_t
       converter_none_convfromucs4(idn_converter_t ctx,
                   void *privdata,
                   const unsigned long *from,
                   char *to, size_t tolen);
static idn_result_t
       converter_none_convtoucs4(idn_converter_t ctx,
                 void *privdata, const char *from,
                 unsigned long *to, size_t tolen);

#ifndef WITHOUT_ICONV
static idn_result_t
       converter_iconv_openfromucs4(idn_converter_t ctx, void **privdata);
static idn_result_t
       converter_iconv_opentoucs4(idn_converter_t ctx, void **privdata);
static idn_result_t
       converter_iconv_close(idn_converter_t ctx, void *privdata);
static idn_result_t
       converter_iconv_convfromucs4(idn_converter_t ctx,
                    void *privdata,
                    const unsigned long *from,
                    char *to, size_t tolen);
static idn_result_t
       converter_iconv_convtoucs4(idn_converter_t ctx,
                  void *privdata,
                  const char *from,
                  unsigned long *to, size_t tolen);

static idn_result_t
iconv_initialize_privdata(void **privdata);
static void
iconv_finalize_privdata(void *privdata);

static char *       get_system_aliasfile(void);
static int      file_exist(const char *filename);

#endif /* !WITHOUT_ICONV */

#ifdef DEBUG
static idn_result_t
       converter_uescape_convfromucs4(idn_converter_t ctx,
                      void *privdata,
                      const unsigned long *from,
                      char *to, size_t tolen);
static idn_result_t
       converter_uescape_convtoucs4(idn_converter_t ctx,
                    void *privdata,
                    const char *from,
                    unsigned long *to,
                    size_t tolen);
#endif /* DEBUG */

static converter_ops_t none_converter_ops = {
    converter_none_open,
    converter_none_open,
    converter_none_convfromucs4,
    converter_none_convtoucs4,
    converter_none_close,
    IDN_NONACE,
};

#ifndef WITHOUT_ICONV
static converter_ops_t iconv_converter_ops = {
    converter_iconv_openfromucs4,
    converter_iconv_opentoucs4,
    converter_iconv_convfromucs4,
    converter_iconv_convtoucs4,
    converter_iconv_close,
    IDN_NONACE,
};
#endif

/*
 * Initialize.
 */

idn_result_t
idn_converter_initialize(void) {
    idn_result_t r;
    idn__strhash_t hash;
    idn__aliaslist_t list;
#ifndef WITHOUT_ICONV
    const char *fname;
#endif

    TRACE(("idn_converter_initialize()\n"));

    if (encoding_name_hash == NULL) {
        if ((r = idn__strhash_create(&hash)) != idn_success)
            goto ret;
        encoding_name_hash = hash;
        r = register_standard_encoding();
    }
    if (encoding_alias_list == NULL) {
        if ((r = idn__aliaslist_create(&list)) != idn_success)
            goto ret;
        encoding_alias_list = list;
#ifndef WITHOUT_ICONV
        fname = get_system_aliasfile();
        if (fname != NULL && file_exist(fname))
            idn_converter_aliasfile(fname);
#endif
    }

    r = idn_success;
ret:
    TRACE(("idn_converter_initialize(): %s\n", idn_result_tostring(r)));
    return (r);
}

#ifndef WITHOUT_ICONV
static char *
get_system_aliasfile() {
#ifdef WIN32
    static char alias_path[500];    /* a good longer than MAX_PATH */

    if (idn__util_getregistrystring(idn__util_hkey_localmachine,
                    IDNVAL_ALIASFILE,
                    alias_path, sizeof(alias_path))) {
        return (alias_path);
    } else {
        return (NULL);
    }
#else
    return (IDN_ALIAS_FILE);
#endif
}

static int
file_exist(const char *filename) {
    FILE  *fp;

    if ((fp = fopen(filename, "r")) == NULL)
        return (0);
    fclose(fp);
    return (1);
}
#endif

idn_result_t
idn_converter_create(const char *name, idn_converter_t *ctxp, int flags) {
    const char *realname;
    idn_converter_t ctx;
    idn_result_t r;
    void *v;

    assert(name != NULL && ctxp != NULL);

    TRACE(("idn_converter_create(%s)\n", name));

    realname = idn_converter_getrealname(name);
#ifdef DEBUG
    if (strcmp(name, realname) != 0) {
        TRACE(("idn_converter_create: realname=%s\n", realname));
    }
#endif

    *ctxp = NULL;

    /* Allocate memory for a converter context and the name. */
    ctx = malloc(sizeof(struct idn_converter) + strlen(realname) + 1);
    if (ctx == NULL) {
        r = idn_nomemory;
        goto ret;
    }

    ctx->local_encoding_name = (char *)(ctx + 1);
    (void)strcpy(ctx->local_encoding_name, realname);
    ctx->flags = flags;
    ctx->reference_count = 1;
    ctx->opened_convfromucs4 = 0;
    ctx->opened_convtoucs4 = 0;
    ctx->private_data = NULL;

    assert(encoding_name_hash != NULL);

    if (strcmp(realname, IDN_UTF8_ENCODING_NAME) == 0) {
        /* No conversion needed */
        ctx->ops = &none_converter_ops;
    } else if ((r = idn__strhash_get(encoding_name_hash, realname, &v))
           == idn_success) {
        /* Special converter found */
        ctx->ops = (converter_ops_t *)v;
    } else {
        /* General case */
#ifdef WITHOUT_ICONV
        free(ctx);
        *ctxp = NULL;
        r = idn_invalid_name;
        goto ret;
#else
        ctx->ops = &iconv_converter_ops;
#endif
    }

    if ((flags & IDN_CONVERTER_DELAYEDOPEN) == 0) {
        r = (ctx->ops->openfromucs4)(ctx, &(ctx->private_data));
        if (r != idn_success) {
            WARNING(("idn_converter_create(): open failed "
                 "(ucs4->local)\n"));
            free(ctx);
            *ctxp = NULL;
            goto ret;
        }
        ctx->opened_convfromucs4 = 1;

        r = (*ctx->ops->opentoucs4)(ctx, &(ctx->private_data));
        if (r != idn_success) {
            WARNING(("idn_converter_create(): open failed "
                 "(local->ucs4)\n"));
            free(ctx);
            *ctxp = NULL;
            goto ret;
        }
        ctx->opened_convtoucs4 = 1;
    }

    *ctxp = ctx;
    r = idn_success;
ret:
    TRACE(("idn_converter_create(): %s\n", idn_result_tostring(r)));
    return (r);
}

void
idn_converter_destroy(idn_converter_t ctx) {
    assert(ctx != NULL);

    TRACE(("idn_converter_destroy(ctx=%s)\n", ctx->local_encoding_name));

    ctx->reference_count--;
    if (ctx->reference_count <= 0) {
        TRACE(("idn_converter_destroy(): the object is destroyed\n"));
        (void)(*ctx->ops->close)(ctx, ctx->private_data);
        free(ctx);
    } else {
        TRACE(("idn_converter_destroy(): "
               "update reference count (%d->%d)\n",
               ctx->reference_count + 1, ctx->reference_count));
    }
}

void
idn_converter_incrref(idn_converter_t ctx) {
    assert(ctx != NULL);

    TRACE(("idn_converter_incrref(ctx=%s)\n", ctx->local_encoding_name));
    TRACE(("idn_converter_incrref: update reference count (%d->%d)\n",
        ctx->reference_count, ctx->reference_count + 1));

    ctx->reference_count++;
}

char *
idn_converter_localencoding(idn_converter_t ctx) {
    assert(ctx != NULL);
    TRACE(("idn_converter_localencoding(ctx=%s)\n",
           ctx->local_encoding_name));
    return (ctx->local_encoding_name);
}

int
idn_converter_encodingtype(idn_converter_t ctx) {
    int encoding_type;

    assert(ctx != NULL);
    TRACE(("idn_converter_encodingtype(ctx=%s)\n",
           ctx->local_encoding_name));

    encoding_type = ctx->ops->encoding_type;
    TRACE(("idn_converter_encodingtype(): %d\n", encoding_type));
    return (encoding_type);
}

int
idn_converter_isasciicompatible(idn_converter_t ctx) {
    int iscompat;

    assert(ctx != NULL);
    TRACE(("idn_converter_isasciicompatible(ctx=%s)\n",
           ctx->local_encoding_name));

    iscompat = (ctx->ops->encoding_type != IDN_NONACE);
    TRACE(("idn_converter_isasciicompatible(): %d\n", iscompat));
    return (iscompat);
}

idn_result_t
idn_converter_convfromucs4(idn_converter_t ctx, const unsigned long *from,
               char *to, size_t tolen) {
    idn_result_t r;

    assert(ctx != NULL && from != NULL && to != NULL);

    TRACE(("idn_converter_convfromucs4(ctx=%s, from=\"%s\", tolen=%d)\n",
           ctx->local_encoding_name, idn__debug_ucs4xstring(from, 50),
           (int)tolen));

    if (!ctx->opened_convfromucs4) {
        r = (*ctx->ops->openfromucs4)(ctx, &(ctx->private_data));
        if (r != idn_success)
            goto ret;
        ctx->opened_convfromucs4 = 1;
    }

    r = (*ctx->ops->convfromucs4)(ctx, ctx->private_data, from, to, tolen);
    if (r != idn_success)
        goto ret;
    if ((ctx->flags & IDN_CONVERTER_RTCHECK) != 0) {
        r = roundtrip_check(ctx, from, to);
        if (r != idn_success)
            goto ret;
    }

    r = idn_success;
ret:
    if (r == idn_success) {
        TRACE(("idn_converter_convfromucs4(): success (to=\"%s\")\n",
               idn__debug_xstring(to, 50)));
    } else {
        TRACE(("idn_converter_convfromucs4(): %s\n",
               idn_result_tostring(r)));
    }
    return (r);
}

idn_result_t
idn_converter_convtoucs4(idn_converter_t ctx, const char *from,
             unsigned long *to, size_t tolen) {
    idn_result_t r;

    assert(ctx != NULL && from != NULL && to != NULL);

    TRACE(("idn_converter_convtoucs4(ctx=%s, from=\"%s\", tolen=%d)\n",
           ctx->local_encoding_name, idn__debug_xstring(from, 50),
           (int)tolen));

    if (!ctx->opened_convtoucs4) {
        r = (*ctx->ops->opentoucs4)(ctx, &(ctx->private_data));
        if (r != idn_success)
            goto ret;
        ctx->opened_convtoucs4 = 1;
    }

    r = (*ctx->ops->convtoucs4)(ctx, ctx->private_data, from, to, tolen);
ret:
    if (r == idn_success) {
        TRACE(("idn_converter_convtoucs4(): success (to=\"%s\")\n",
               idn__debug_ucs4xstring(to, 50)));
    } else {
        TRACE(("idn_converter_convtoucs4(): %s\n",
               idn_result_tostring(r)));
    }
    return (r);
}

/*
 * Encoding registration.
 */

idn_result_t
idn_converter_register(const char *name,
               idn_converter_openproc_t openfromucs4,
               idn_converter_openproc_t opentoucs4,
               idn_converter_convfromucs4proc_t convfromucs4,
               idn_converter_convtoucs4proc_t convtoucs4,
               idn_converter_closeproc_t close,
               int encoding_type) {
    converter_ops_t *ops;
    idn_result_t r;

    assert(name != NULL && convfromucs4 != NULL && convtoucs4 != NULL);

    TRACE(("idn_converter_register(name=%s)\n", name));

    if ((ops = malloc(sizeof(*ops))) == NULL) {
        r = idn_nomemory;
        goto ret;
    }

    if (openfromucs4 == NULL)
        openfromucs4 = converter_none_open;
    if (opentoucs4 == NULL)
        opentoucs4 = converter_none_open;
    if (close == NULL)
        close = converter_none_close;

    ops->openfromucs4 = openfromucs4;
    ops->opentoucs4 = opentoucs4;
    ops->convfromucs4 = convfromucs4;
    ops->convtoucs4 = convtoucs4;
    ops->close = close;
    ops->encoding_type = encoding_type;

    r = idn__strhash_put(encoding_name_hash, name, ops);
    if (r != idn_success) {
        free(ops);
        goto ret;
    }

    r = idn_success;
ret:
    TRACE(("idn_converter_register(): %s\n", idn_result_tostring(r)));
    return (r);
}

static idn_result_t
register_standard_encoding(void) {
    idn_result_t r;

    r = idn_converter_register(IDN_PUNYCODE_ENCODING_NAME,
                   NULL,
                   NULL,
                   idn__punycode_encode,
                   idn__punycode_decode,
                   converter_none_close,
                   IDN_ACE_STRICTCASE);
    if (r != idn_success)
        return (r);

#ifdef IDN_EXTRA_ACE
    r = idn_converter_register(IDN_AMCACEZ_ENCODING_NAME,
                   NULL,
                   NULL,
                   idn__punycode_encode,
                   idn__punycode_decode,
                   converter_none_close,
                   IDN_ACE_STRICTCASE);
    if (r != idn_success)
        return (r);

    r = idn_converter_register(IDN_RACE_ENCODING_NAME,
                   NULL,
                   NULL,
                   idn__race_encode,
                   idn__race_decode,
                   converter_none_close,
                   IDN_ACE_LOOSECASE);
    if (r != idn_success)
        return (r);
#endif /* IDN_EXTRA_ACE */

#ifdef DEBUG
    /* This is convenient for debug.  Not useful for other purposes. */
    r = idn_converter_register("U-escape",
                   NULL,
                   NULL,
                   converter_uescape_convfromucs4,
                   converter_uescape_convtoucs4,
                   NULL,
                   IDN_NONACE);
    if (r != idn_success)
        return (r);
#endif /* DEBUG */

    return (r);
}

/*
 * Encoding alias support.
 */
idn_result_t
idn_converter_addalias(const char *alias_name, const char *real_name,
               int first_item) {
    idn_result_t r;

    assert(alias_name != NULL && real_name != NULL);

    TRACE(("idn_converter_addalias(alias_name=%s,real_name=%s)\n",
           alias_name, real_name));

    if (strlen(alias_name) == 0 || strlen(real_name) == 0) {
        return idn_invalid_syntax;
    }

    if (strcmp(alias_name, real_name) == 0) {
        r = idn_success;
        goto ret;
    }

    if (encoding_alias_list == NULL) {
        WARNING(("idn_converter_addalias(): the module is not "
             "initialized\n"));
        r = idn_failure;
        goto ret;
    }

    r = idn__aliaslist_additem(encoding_alias_list, alias_name, real_name,
                   first_item);
ret:
    TRACE(("idn_converter_addalias(): %s\n", idn_result_tostring(r)));
    return (r);
}

idn_result_t
idn_converter_aliasfile(const char *path) {
    idn_result_t r;

    assert(path != NULL);

    TRACE(("idn_converter_aliasfile(path=%s)\n", path));

    if (encoding_alias_list == NULL) {
        WARNING(("idn_converter_aliasfile(): the module is not "
             "initialized\n"));
        return (idn_failure);
    }

    r = idn__aliaslist_aliasfile(encoding_alias_list, path);

    TRACE(("idn_converter_aliasfile(): %s\n", idn_result_tostring(r)));
    return (r);
}

idn_result_t
idn_converter_resetalias(void) {
    idn__aliaslist_t list;
    idn_result_t r;

    TRACE(("idn_converter_resetalias()\n"));

    if (encoding_alias_list == NULL) {
        WARNING(("idn_converter_resetalias(): the module is not "
             "initialized\n"));
        return (idn_failure);
    }

    list = encoding_alias_list;
    encoding_alias_list = NULL;
    idn__aliaslist_destroy(list);
    list = NULL;
    r = idn__aliaslist_create(&list);
    encoding_alias_list = list;

    TRACE(("idn_converter_resetalias(): %s\n", idn_result_tostring(r)));
    return (r);
}

const char *
idn_converter_getrealname(const char *name) {
    char *realname;
    idn_result_t r;

    TRACE(("idn_converter_getrealname()\n"));

    assert(name != NULL);

    if (encoding_alias_list == NULL) {
        WARNING(("idn_converter_getrealname(): the module is not "
             "initialized\n"));
        return (name);
    }

    r = idn__aliaslist_find(encoding_alias_list, name, &realname);
    if (r != idn_success) {
        return (name);
    }
    return (realname);
}

/*
 * Round trip check.
 */

static idn_result_t
roundtrip_check(idn_converter_t ctx, const unsigned long *from, const char *to)
{
    /*
     * One problem with iconv() convertion is that
     * iconv() doesn't signal an error if the input
     * string contains characters which are valid but
     * do not have mapping to the output codeset.
     * (the behavior of iconv() for that case is defined as
     * `implementation dependent')
     * One way to check this case is to perform round-trip
     * conversion and see if it is same as the original string.
     */
    idn_result_t r;
    unsigned long *back;
    unsigned long backbuf[256];
    size_t fromlen;
    size_t backlen;

    TRACE(("idn_converter_convert: round-trip checking (from=\"%s\")\n",
           idn__debug_ucs4xstring(from, 50)));

    /* Allocate enough buffer. */
    fromlen = idn_ucs4_strlen(from) + 1;
    if (fromlen * sizeof(*back) <= sizeof(backbuf)) {
        backlen = sizeof(backbuf);
        back = backbuf;
    } else {
        backlen = fromlen;
        back = (unsigned long *)malloc(backlen * sizeof(*back));
        if (back == NULL)
            return (idn_nomemory);
    }

    /*
     * Perform backward conversion.
     */
    r = idn_converter_convtoucs4(ctx, to, back, backlen);
    switch (r) {
    case idn_success:
        if (memcmp(back, from, sizeof(*from) * fromlen) != 0)
            r = idn_nomapping;
        break;
    case idn_invalid_encoding:
    case idn_buffer_overflow:
        r = idn_nomapping;
        break;
    default:
        break;
    }

    if (back != backbuf)
        free(back);

    if (r != idn_success) {
        TRACE(("round-trip check failed: %s\n",
               idn_result_tostring(r)));
    }

    return (r);
}

/*
 * Identity conversion (or, no conversion at all).
 */

static idn_result_t
converter_none_open(idn_converter_t ctx, void **privdata) {
    assert(ctx != NULL);

    return (idn_success);
}

static idn_result_t
converter_none_close(idn_converter_t ctx, void *privdata) {
    assert(ctx != NULL);

    return (idn_success);
}

static idn_result_t
converter_none_convfromucs4(idn_converter_t ctx, void *privdata,
               const unsigned long *from, char *to, size_t tolen) {
    assert(ctx != NULL && from != NULL && to != NULL);

    return idn_ucs4_ucs4toutf8(from, to, tolen);
}

static idn_result_t
converter_none_convtoucs4(idn_converter_t ctx, void *privdata,
             const char *from, unsigned long *to, size_t tolen) {
    assert(ctx != NULL && from != NULL && to != NULL);

    return idn_ucs4_utf8toucs4(from, to, tolen);
}

#ifndef WITHOUT_ICONV

/*
 * Conversion using iconv() interface.
 */

static idn_result_t
converter_iconv_openfromucs4(idn_converter_t ctx, void **privdata) {
    iconv_t *ictxp;
    idn_result_t r;

    assert(ctx != NULL);

    r = iconv_initialize_privdata(privdata);
    if (r != idn_success)
        return (r);

    ictxp = (iconv_t *)*privdata;
    *ictxp = iconv_open(ctx->local_encoding_name, IDN_UTF8_ENCODING_NAME);
    if (*ictxp == (iconv_t)(-1)) {
        free(*privdata);
        *privdata = NULL;
        switch (errno) {
        case ENOMEM:
            return (idn_nomemory);
        case EINVAL:
            return (idn_invalid_name);
        default:
            WARNING(("iconv_open failed with errno %d\n", errno));
            return (idn_failure);
        }
    }

    return (idn_success);
}

static idn_result_t
converter_iconv_opentoucs4(idn_converter_t ctx, void **privdata) {
    iconv_t *ictxp;
    idn_result_t r;

    assert(ctx != NULL);

    r = iconv_initialize_privdata(privdata);
    if (r != idn_success)
        return (r);

    ictxp = (iconv_t *)*privdata + 1;
    *ictxp = iconv_open(IDN_UTF8_ENCODING_NAME, ctx->local_encoding_name);
    if (*ictxp == (iconv_t)(-1)) {
        free(*privdata);
        *privdata = NULL;
        switch (errno) {
        case ENOMEM:
            return (idn_nomemory);
        case EINVAL:
            return (idn_invalid_name);
        default:
            WARNING(("iconv_open failed with errno %d\n", errno));
            return (idn_failure);
        }
    }

    return (idn_success);
}

static idn_result_t
iconv_initialize_privdata(void **privdata) {
    if (*privdata == NULL) {
        *privdata = malloc(sizeof(iconv_t) * 2);
        if (*privdata == NULL)
            return (idn_nomemory);
        *((iconv_t *)*privdata) = (iconv_t)(-1);
        *((iconv_t *)*privdata + 1) = (iconv_t)(-1);
    }

    return (idn_success);
}

static void
iconv_finalize_privdata(void *privdata) {
    iconv_t *ictxp;

    if (privdata != NULL) {
        ictxp = (iconv_t *)privdata;
        if (*ictxp != (iconv_t)(-1))
            iconv_close(*ictxp);

        ictxp++;
        if (*ictxp != (iconv_t)(-1))
            iconv_close(*ictxp);
        free(privdata);
    }
}

static idn_result_t
converter_iconv_close(idn_converter_t ctx, void *privdata) {
    assert(ctx != NULL);

    iconv_finalize_privdata(privdata);

    return (idn_success);
}

static idn_result_t
converter_iconv_convfromucs4(idn_converter_t ctx, void *privdata,
                 const unsigned long *from, char *to,
                 size_t tolen) {
    iconv_t ictx;
    char *utf8 = NULL;
    size_t utf8size = 256;  /* large enough */
    idn_result_t r;
    size_t sz;
    size_t inleft;
    size_t outleft;
    char *inbuf, *outbuf;

    assert(ctx != NULL && from != NULL && to != NULL);

    if (tolen <= 0) {
        r = idn_buffer_overflow;    /* need space for NUL */
        goto ret;
    }

    /*
     * UCS4 -> UTF-8 conversion.
     */
    utf8 = (char *)malloc(utf8size);
    if (utf8 == NULL) {
        r = idn_nomemory;
        goto ret;
    }

try_again:
    r = idn_ucs4_ucs4toutf8(from, utf8, utf8size);
    if (r == idn_buffer_overflow) {
        char *new_utf8;

        utf8size *= 2;
        new_utf8 = (char *)realloc(utf8, utf8size);
        if (new_utf8 == NULL) {
            r = idn_nomemory;
            goto ret;
        }
        utf8 = new_utf8;
        goto try_again;
    } else if (r != idn_success) {
        goto ret;
    }

    ictx = ((iconv_t *)privdata)[0];

    /*
     * Reset internal state.
     *
     * The following code should work according to the SUSv2 spec,
     * but causes segmentation fault with Solaris 2.6.
     * So.. a work-around.
     *
     * (void)iconv(ictx, (const char **)NULL, (size_t *)NULL,
     *      (char **)NULL, (size_t *)NULL);
     */
    inleft = 0;
    outbuf = NULL;
    outleft = 0;
    (void)iconv(ictx, (const char **)NULL, &inleft, &outbuf, &outleft);

    inleft = strlen(utf8);
    inbuf = utf8;
    outleft = tolen - 1;    /* reserve space for terminating NUL */
    sz = iconv(ictx, (const char **)&inbuf, &inleft, &to, &outleft);

    if (sz == (size_t)(-1) || inleft > 0) {
        switch (errno) {
        case EILSEQ:
        case EINVAL:
            /*
             * We already checked the validity of the input
             * string.  So we assume a mapping error.
             */
            r = idn_nomapping;
            goto ret;
        case E2BIG:
            r = idn_buffer_overflow;
            goto ret;
        default:
            WARNING(("iconv failed with errno %d\n", errno));
            r = idn_failure;
            goto ret;
        }
    }

    /*
     * For UTF-8 -> local conversion, append a sequence of
     * state reset.
     */
    inleft = 0;
    sz = iconv(ictx, (const char **)NULL, &inleft, &to, &outleft);
    if (sz == (size_t)(-1)) {
        switch (errno) {
        case EILSEQ:
        case EINVAL:
            r = idn_invalid_encoding;
            goto ret;
        case E2BIG:
            r = idn_buffer_overflow;
            goto ret;
        default:
            WARNING(("iconv failed with errno %d\n", errno));
            r = idn_failure;
            goto ret;
        }
    }
    *to = '\0';
    r = idn_success;

ret:
    free(utf8);
    return (r);

}

static idn_result_t
converter_iconv_convtoucs4(idn_converter_t ctx, void *privdata,
               const char *from, unsigned long *to, size_t tolen) {
    iconv_t ictx;
    char *utf8 = NULL;
    size_t utf8size = 256;  /* large enough */
    idn_result_t r;
    size_t sz;
    size_t inleft;
    size_t outleft;
    const char *from_ptr;
    char *outbuf;

    assert(ctx != NULL && from != NULL && to != NULL);

    if (tolen <= 0) {
        r = idn_buffer_overflow;    /* need space for NUL */
        goto ret;
    }
    ictx = ((iconv_t *)privdata)[1];
    utf8 = (char *)malloc(utf8size);
    if (utf8 == NULL) {
        r = idn_nomemory;
        goto ret;
    }

try_again:
    /*
     * Reset internal state.
     */
    inleft = 0;
    outbuf = NULL;
    outleft = 0;
    (void)iconv(ictx, (const char **)NULL, &inleft, &outbuf, &outleft);

    from_ptr = from;
    inleft = strlen(from);
    outbuf = utf8;
    outleft = utf8size - 1;    /* reserve space for terminating NUL */
    sz = iconv(ictx, (const char **)&from_ptr, &inleft, &outbuf, &outleft);

    if (sz == (size_t)(-1) || inleft > 0) {
        char *new_utf8;

        switch (errno) {
        case EILSEQ:
        case EINVAL:
            /*
             * We assume all the characters in the local
             * codeset are included in UCS.  This means mapping
             * error is not possible, so the input string must
             * have some problem.
             */
            r = idn_invalid_encoding;
            goto ret;
        case E2BIG:
            utf8size *= 2;
            new_utf8 = (char *)realloc(utf8, utf8size);
            if (new_utf8 == NULL) {
                r = idn_nomemory;
                goto ret;
            }
            utf8 = new_utf8;
            goto try_again;
        default:
            WARNING(("iconv failed with errno %d\n", errno));
            r = idn_failure;
            goto ret;
        }
    }
    *outbuf = '\0';

    /*
     * UTF-8 -> UCS4 conversion.
     */
    r = idn_ucs4_utf8toucs4(utf8, to, tolen);

ret:
    free(utf8);
    return (r);
}

#endif /* !WITHOUT_ICONV */

#ifdef DEBUG
/*
 * Conversion to/from unicode escape string.
 * Arbitrary UCS-4 character can be specified by a special sequence
 *  \u{XXXXXX}
 * where XXXXX denotes any hexadecimal string up to FFFFFFFF.
 * This is designed for debugging.
 */

static idn_result_t
converter_uescape_convfromucs4(idn_converter_t ctx, void *privdata,
              const unsigned long *from, char *to,
              size_t tolen) {
    idn_result_t r;
    unsigned long v;

    while (*from != '\0') {
        v = *from++;

        if (v <= 0x7f) {
            if (tolen < 1) {
                r = idn_buffer_overflow;
                goto failure;
            }
            *to++ = v;
            tolen--;
        } else if (v <= 0xffffffff) {
            char tmp[20];
            int len;

            (void)sprintf(tmp, "\\u{%lx}", v);
            len = strlen(tmp);
            if (tolen < len) {
                r = idn_buffer_overflow;
                goto failure;
            }
            (void)memcpy(to, tmp, len);
            to += len;
            tolen -= len;
        } else {
            r = idn_invalid_encoding;
            goto failure;
        }
    }

    if (tolen <= 0) {
        r = idn_buffer_overflow;
        goto failure;
    }
    *to = '\0';

    return (idn_success);

failure:
    if (r != idn_buffer_overflow) {
        WARNING(("idn_uescape_convfromucs4(): %s\n",
             idn_result_tostring(r)));
    }
    return (r);
}

static idn_result_t
converter_uescape_convtoucs4(idn_converter_t ctx, void *privdata,
            const char *from, unsigned long *to, size_t tolen)
{
    idn_result_t r;
    size_t fromlen = strlen(from);

    while (*from != '\0') {
        if (tolen <= 0) {
            r = idn_buffer_overflow;
            goto failure;
        }
        if (strncmp(from, "\\u{", 3) == 0 ||
            strncmp(from, "\\U{", 3) == 0) {
            size_t ullen;
            unsigned long v;
            char *end;

            v = strtoul(from + 3, &end, 16);
            ullen = end - (from + 3);
            if (*end == '}' && ullen > 1 && ullen < 8) {
                *to = v;
                from = end + 1;
                fromlen -= ullen;
            } else {
                *to = '\\';
                from++;
                fromlen--;
            }
        } else {
            int c = *(unsigned char *)from;
            size_t width;
            char buf[8];

            if (c < 0x80)
                width = 1;
            else if (c < 0xc0)
                width = 0;
            else if (c < 0xe0)
                width = 2;
            else if (c < 0xf0)
                width = 3;
            else if (c < 0xf8)
                width = 4;
            else if (c < 0xfc)
                width = 5;
            else if (c < 0xfe)
                width = 6;
            else
                width = 0;
            if (width == 0 || width > fromlen) {
                r = idn_invalid_encoding;
                goto failure;
            }

            memcpy(buf, from, width);
            buf[width] = '\0';
            r = idn_ucs4_utf8toucs4(buf, to, tolen);
            if (r != idn_success) {
                r = idn_invalid_encoding;
                goto failure;
            }
            from += width;
            fromlen -= width;
        }
        to++;
        tolen--;
    }

    if (tolen <= 0) {
        r = idn_buffer_overflow;
        goto failure;
    }
    *to = '\0';

    return (idn_success);

failure:
    if (r != idn_buffer_overflow) {
        WARNING(("idn_uescape_convtoucs4(): %s\n",
             idn_result_tostring(r)));
    }
    return (r);
}

#endif