/*

 * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

#include <stdio.h>

#include <stddef.h>

#include <stdlib.h>

#include <string.h>

#include <ctype.h>

#include <locale.h>

#include <langinfo.h>

#include <iconv.h>

/* Routines to convert back and forth between Platform Encoding and UTF-8 */

/* Use THIS_FILE when it is available. */

#ifndef THIS_FILE

    #define THIS_FILE __FILE__

#endif

/* Error and assert macros */

#define UTF_ERROR(m) utfError(THIS_FILE, __LINE__,  m)

#define UTF_ASSERT(x) ( (x)==0 ? UTF_ERROR("ASSERT ERROR " #x) : (void)0 )

#define UTF_DEBUG(x)

/* Global variables */

static iconv_t iconvToPlatform          = (iconv_t)-1;

static iconv_t iconvFromPlatform        = (iconv_t)-1;

/*

 * Error handler

 */

static void

utfError(char *file, int line, char *message)

{

    (void)fprintf(stderr, "UTF ERROR [\"%s\":%d]: %s\n", file, line, message);

    abort();

}

/*

 * Initialize all utf processing.

 */

static void

utfInitialize(void)

{

    const char* codeset;

    /* Set the locale from the environment */

    (void)setlocale(LC_ALL, "");

    /* Get the codeset name */

    codeset = (char*)nl_langinfo(CODESET);

    if ( codeset == NULL || codeset[0] == 0 ) {

        UTF_DEBUG(("NO codeset returned by nl_langinfo(CODESET)\n"));

        return;

    }

    UTF_DEBUG(("Codeset = %s\n", codeset));

#ifdef MACOSX

    /* On Mac, if US-ASCII, but with no env hints, use UTF-8 */

    const char* env_lang = getenv("LANG");

    const char* env_lc_all = getenv("LC_ALL");

    const char* env_lc_ctype = getenv("LC_CTYPE");

    if (strcmp(codeset,"US-ASCII") == 0 &&

        (env_lang == NULL || strlen(env_lang) == 0) &&

        (env_lc_all == NULL || strlen(env_lc_all) == 0) &&

        (env_lc_ctype == NULL || strlen(env_lc_ctype) == 0)) {

        codeset = "UTF-8";

    }

#endif

    /* If we don't need this, skip it */

    if (strcmp(codeset, "UTF-8") == 0 || strcmp(codeset, "utf8") == 0 ) {

        UTF_DEBUG(("NO iconv() being used because it is not needed\n"));

        return;

    }

    /* Open conversion descriptors */

    iconvToPlatform   = iconv_open(codeset, "UTF-8");

    if ( iconvToPlatform == (iconv_t)-1 ) {

        UTF_ERROR("Failed to complete iconv_open() setup");

    }

    iconvFromPlatform = iconv_open("UTF-8", codeset);

    if ( iconvFromPlatform == (iconv_t)-1 ) {

        UTF_ERROR("Failed to complete iconv_open() setup");

    }

}

/*

 * Terminate all utf processing

 */

static void

utfTerminate(void)

{

    if ( iconvFromPlatform!=(iconv_t)-1 ) {

        (void)iconv_close(iconvFromPlatform);

    }

    if ( iconvToPlatform!=(iconv_t)-1 ) {

        (void)iconv_close(iconvToPlatform);

    }

    iconvToPlatform   = (iconv_t)-1;

    iconvFromPlatform = (iconv_t)-1;

}

/*

 * Do iconv() conversion.

 *    Returns length or -1 if output overflows.

 */

static int

iconvConvert(iconv_t ic, char *bytes, int len, char *output, int outputMaxLen)

{

    int outputLen = 0;

    UTF_ASSERT(bytes);

    UTF_ASSERT(len>=0);

    UTF_ASSERT(output);

    UTF_ASSERT(outputMaxLen>len);

    output[0] = 0;

    outputLen = 0;

    if ( ic != (iconv_t)-1 ) {

        int          returnValue;

        size_t       inLeft;

        size_t       outLeft;

        char        *inbuf;

        char        *outbuf;

        inbuf        = bytes;

        outbuf       = output;

        inLeft       = len;

        outLeft      = outputMaxLen;

        returnValue  = iconv(ic, (void*)&inbuf, &inLeft, &outbuf, &outLeft);

        if ( returnValue >= 0 && inLeft==0 ) {

            outputLen = outputMaxLen-outLeft;

            output[outputLen] = 0;

            return outputLen;

        }

        /* Failed to do the conversion */

        UTF_DEBUG(("iconv() failed to do the conversion\n"));

        return -1;

    }

    /* Just copy bytes */

    outputLen = len;

    (void)memcpy(output, bytes, len);

    output[len] = 0;

    return outputLen;

}

/*

 * Convert UTF-8 to Platform Encoding.

 *    Returns length or -1 if output overflows.

 */

static int

utf8ToPlatform(char *utf8, int len, char *output, int outputMaxLen)

{

    return iconvConvert(iconvToPlatform, utf8, len, output, outputMaxLen);

}

/*

 * Convert Platform Encoding to UTF-8.

 *    Returns length or -1 if output overflows.

 */

static int

platformToUtf8(char *str, int len, char *output, int outputMaxLen)

{

    return iconvConvert(iconvFromPlatform, str, len, output, outputMaxLen);

}

int

convertUft8ToPlatformString(char* utf8_str, int utf8_len, char* platform_str, int platform_len) {

    if (iconvToPlatform ==  (iconv_t)-1) {

        utfInitialize();

    }

    return utf8ToPlatform(utf8_str, utf8_len, platform_str, platform_len);

}