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/*

 * Copyright (c) 2006 Josef Cejka

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 *

 * - Redistributions of source code must retain the above copyright

 *   notice, this list of conditions and the following disclaimer.

 * - 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.

 * - The name of the author may not be used to endorse or promote products

 *   derived from this software without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 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.

 */

/** @addtogroup generic

 * @{

 */

/** @file

 */

#include <print.h>

#include <printf/printf_core.h>

#include <string.h>

#include <memstr.h>

typedef struct {

    size_t size;    /* Total size of the buffer (in bytes) */

    size_t len;     /* Number of already used bytes */

    char *dst;      /* Destination */

} vsnprintf_data_t;

/** Write UTF-8 string to given buffer.

 *

 * Write at most data->size plain characters including trailing zero.

 * According to C99, snprintf() has to return number of characters that

 * would have been written if enough space had been available. Hence

 * the return value is not the number of actually printed characters

 * but size of the input string.

 *

 * @param str  Source UTF-8 string to print.

 * @param size Number of plain characters in str.

 * @param data Structure describing destination string, counter

 *             of used space and total string size.

 *

 * @return Number of UTF-8 characters to print (not characters actually

 *         printed).

 *

 */

static int vsnprintf_write_utf8(const char *str, size_t size, vsnprintf_data_t *data)

{

    size_t left = data->size - data->len;

    if (left == 0)

        return ((int) size);

    if (left == 1) {

        /* We have only one free byte left in buffer

         * -> store trailing zero

         */

        data->dst[data->size - 1] = 0;

        data->len = data->size;

        return ((int) size);

    }

    if (left <= size) {

        /* We have not enought space for whole string

         * with the trailing zero => print only a part

         * of string

         */

        index_t index = 0;

        while (index < size) {

            wchar_t uc = chr_decode(str, &index, size);

            if (!chr_encode(uc, data->dst, &data->len, data->size - 1))

                break;

        }

        /* Put trailing zero at end, but not count it

         * into data->len so it could be rewritten next time

         */

        data->dst[data->len] = 0;

        return ((int) size);

    }

    /* Buffer is big enought to print the whole string */

    memcpy((void *)(data->dst + data->len), (void *) str, size);

    data->len += size;

    /* Put trailing zero at end, but not count it

     * into data->len so it could be rewritten next time

     */

    data->dst[data->len] = 0;

    return ((int) size);

}

/** Write UTF-32 string to given buffer.

 *

 * Write at most data->size plain characters including trailing zero.

 * According to C99, snprintf() has to return number of characters that

 * would have been written if enough space had been available. Hence

 * the return value is not the number of actually printed characters

 * but size of the input string.

 *

 * @param str  Source UTF-32 string to print.

 * @param size Number of bytes in str.

 * @param data Structure describing destination string, counter

 *             of used space and total string size.

 *

 * @return Number of UTF-8 characters to print (not characters actually

 *         printed).

 *

 */

static int vsnprintf_write_utf32(const wchar_t *str, size_t size, vsnprintf_data_t *data)

{

    index_t index = 0;

    while (index < (size / sizeof(wchar_t))) {

        size_t left = data->size - data->len;

        if (left == 0)

            return ((int) size);

        if (left == 1) {

            /* We have only one free byte left in buffer

             * -> store trailing zero

             */

            data->dst[data->size - 1] = 0;

            data->len = data->size;

            return ((int) size);

        }

        if (!chr_encode(str[index], data->dst, &data->len, data->size - 1))

            break;

        index++;

    }

    /* Put trailing zero at end, but not count it

     * into data->len so it could be rewritten next time

     */

    data->dst[data->len] = 0;

    return ((int) size);

}

int vsnprintf(char *str, size_t size, const char *fmt, va_list ap)

{

    vsnprintf_data_t data = {

        size,

        0,

        str

    };

    printf_spec_t ps = {

        (int(*) (const char *, size_t, void *)) vsnprintf_write_utf8,

        (int(*) (const wchar_t *, size_t, void *)) vsnprintf_write_utf32,

        &data

    };

    /* Print 0 at end of string - fix the case that nothing will be printed */

    if (size > 0)

        str[0] = 0;

    /* vsnprintf_write ensures that str will be terminated by zero. */

    return printf_core(fmt, &ps, ap);

}

/** @}

 */