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1271 cejka 1
/*
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 * Copyright (c) 2006 Josef Cejka
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 * All rights reserved.
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 *
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 * Redistribution and use in source and binary forms, with or without
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 * modification, are permitted provided that the following conditions
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 * are met:
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 *
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 * - Redistributions of source code must retain the above copyright
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 *   notice, this list of conditions and the following disclaimer.
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 * - Redistributions in binary form must reproduce the above copyright
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 *   notice, this list of conditions and the following disclaimer in the
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 *   documentation and/or other materials provided with the distribution.
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 * - The name of the author may not be used to endorse or promote products
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 *   derived from this software without specific prior written permission.
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 *
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 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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 */
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/** @addtogroup generic
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 * @{
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 */
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/** @file
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 */
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#include <print.h>
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#include <printf/printf_core.h>
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#include <string.h>
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#include <memstr.h>
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typedef struct {
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    size_t size;    /* Total size of the buffer (in bytes) */
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    size_t len;     /* Number of already used bytes */
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    char *dst;      /* Destination */
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} vsnprintf_data_t;
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/** Write UTF-8 string to given buffer.
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 *
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 * Write at most data->size plain characters including trailing zero.
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 * According to C99, snprintf() has to return number of characters that
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 * would have been written if enough space had been available. Hence
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 * the return value is not the number of actually printed characters
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 * but size of the input string.
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 *
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 * @param str  Source UTF-8 string to print.
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 * @param size Number of plain characters in str.
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 * @param data Structure describing destination string, counter
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 *             of used space and total string size.
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 *
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 * @return Number of UTF-8 characters to print (not characters actually
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 *         printed).
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 *
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 */
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static int vsnprintf_write_utf8(const char *str, size_t size, vsnprintf_data_t *data)
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{
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    size_t left = data->size - data->len;
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    if (left == 0)
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        return ((int) size);
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    if (left == 1) {
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        /* We have only one free byte left in buffer
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         * -> store trailing zero
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         */
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        data->dst[data->size - 1] = 0;
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        data->len = data->size;
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        return ((int) size);
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    }
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    if (left <= size) {
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        /* We have not enought space for whole string
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         * with the trailing zero => print only a part
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         * of string
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         */
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        index_t index = 0;
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        while (index < size) {
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            wchar_t uc = chr_decode(str, &index, size);
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            if (!chr_encode(uc, data->dst, &data->len, data->size - 1))
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                break;
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        }
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        /* Put trailing zero at end, but not count it
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         * into data->len so it could be rewritten next time
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         */
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        data->dst[data->len] = 0;
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        return ((int) size);
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    }
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    /* Buffer is big enought to print the whole string */
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    memcpy((void *)(data->dst + data->len), (void *) str, size);
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    data->len += size;
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    /* Put trailing zero at end, but not count it
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     * into data->len so it could be rewritten next time
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     */
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    data->dst[data->len] = 0;
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    return ((int) size);
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}
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/** Write UTF-32 string to given buffer.
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 *
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 * Write at most data->size plain characters including trailing zero.
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 * According to C99, snprintf() has to return number of characters that
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 * would have been written if enough space had been available. Hence
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 * the return value is not the number of actually printed characters
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 * but size of the input string.
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 *
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 * @param str  Source UTF-32 string to print.
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 * @param size Number of bytes in str.
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 * @param data Structure describing destination string, counter
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 *             of used space and total string size.
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 *
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 * @return Number of UTF-8 characters to print (not characters actually
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 *         printed).
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 *
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 */
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static int vsnprintf_write_utf32(const wchar_t *str, size_t size, vsnprintf_data_t *data)
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{
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    index_t index = 0;
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    while (index < (size / sizeof(wchar_t))) {
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        size_t left = data->size - data->len;
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        if (left == 0)
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            return ((int) size);
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        if (left == 1) {
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            /* We have only one free byte left in buffer
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             * -> store trailing zero
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             */
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            data->dst[data->size - 1] = 0;
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            data->len = data->size;
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            return ((int) size);
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        }
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        if (!chr_encode(str[index], data->dst, &data->len, data->size - 1))
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            break;
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        index++;
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    }
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    /* Put trailing zero at end, but not count it
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     * into data->len so it could be rewritten next time
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     */
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    data->dst[data->len] = 0;
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    return ((int) size);
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}
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int vsnprintf(char *str, size_t size, const char *fmt, va_list ap)
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{
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    vsnprintf_data_t data = {
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        size,
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        0,
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        str
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    };
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    printf_spec_t ps = {
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        (int(*) (const char *, size_t, void *)) vsnprintf_write_utf8,
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        (int(*) (const wchar_t *, size_t, void *)) vsnprintf_write_utf32,
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        &data
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    };
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    /* Print 0 at end of string - fix the case that nothing will be printed */
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    if (size > 0)
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        str[0] = 0;
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    /* vsnprintf_write ensures that str will be terminated by zero. */
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    return printf_core(fmt, &ps, ap);
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}
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/** @}
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 */