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#include <stdio.h>
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#include <stdio.h>
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#include <string.h>
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#include <string.h>
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#include <io/printf_core.h>
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#include <io/printf_core.h>
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struct vsnprintf_data {
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struct vsnprintf_data {
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    size_t size; /* total space for string */
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    size_t size;    /* total space for string */
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    size_t len; /* count of currently used characters */
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    size_t len; /* count of currently used characters */
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    char *string; /* destination string */
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    char *string;   /* destination string */
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};
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};
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/** Write string to given buffer.
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/** Write string to given buffer.
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 * Write at most data->size characters including trailing zero. According to C99 has snprintf to return number
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 * Write at most data->size characters including trailing zero. According to C99
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 * has snprintf to return number of characters that would have been written if
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 * of characters that would have been written if enough space had been available. Hence the return value is not
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 * enough space had been available. Hence the return value is not number of
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 * number of really printed characters but size of input string. Number of really used characters
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 * really printed characters but size of input string. Number of really used
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 * is stored in data->len.
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 * characters is stored in data->len.
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 *
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 * @param str source string to print
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 * @param str       Source string to print.
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 * @param count size of source string
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 * @param count     Size of the source string.
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 * @param data structure with destination string, counter of used space and total string size.
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 * @param data      Structure with destination string, counter of used space
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 *          and total string size.
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 * @return number of characters to print (not characters really printed!)
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 * @return      Number of characters to print (not characters really
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 *          printed!)
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 */
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 */
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static int
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static int vsnprintf_write(const char *str, size_t count, struct vsnprintf_data *data)
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vsnprintf_write(const char *str, size_t count, struct vsnprintf_data *data)
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{
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{
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    size_t i;
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    size_t i;
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    i = data->size - data->len;
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    i = data->size - data->len;
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    if (i == 0) {
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    if (i == 0) {
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        return count;
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        return count;
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    }
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    }
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    if (i == 1) {
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    if (i == 1) {
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        /*
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        /* We have only one free byte left in buffer => write there trailing zero */
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         * We have only one free byte left in buffer => write there
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         * trailing zero.
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         */
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        data->string[data->size - 1] = 0;
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        data->string[data->size - 1] = 0;
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        data->len = data->size;
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        data->len = data->size;
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        return count;
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        return count;
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    }
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    }
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    if (i <= count) {
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    if (i <= count) {
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        /*
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        /* We have not enought space for whole string with the trailing zero => print only a part of string */
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         * We have not enought space for whole string with the trailing
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         * zero => print only a part of string.
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         */
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            memcpy((void *)(data->string + data->len), (void *)str, i - 1);
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        memcpy((void *)(data->string + data->len), (void *)str, i - 1);
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            data->string[data->size - 1] = 0;
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        data->string[data->size - 1] = 0;
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            data->len = data->size;
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        data->len = data->size;
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            return count;
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        return count;
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    }
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    }
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    /* Buffer is big enought to print whole string */
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    /* Buffer is big enought to print whole string */
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    memcpy((void *)(data->string + data->len), (void *)str, count);
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    memcpy((void *)(data->string + data->len), (void *)str, count);
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    data->len += count;
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    data->len += count;
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    /*
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    /* Put trailing zero at end, but not count it into data->len so it could be rewritten next time */
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     * Put trailing zero at end, but not count it into data->len so it could
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     * be rewritten next time.
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     */
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    data->string[data->len] = 0;
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    data->string[data->len] = 0;
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    return count;  
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    return count;  
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}
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}
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/** Print formatted to the given buffer with limited size.
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/** Print formatted to the given buffer with limited size.
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 * @param str   buffer
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 * @param str       Buffer.
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 * @param size  buffer size
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 * @param size      Bffer size.
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 * @param fmt   format string
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 * @param fmt       Format string.
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 * \see For more details about format string see printf_core.
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 * \see For more details about format string see printf_core.
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 */
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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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int vsnprintf(char *str, size_t size, const char *fmt, va_list ap)
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{
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{
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    struct vsnprintf_data data = {size, 0, str};
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    struct vsnprintf_data data = {size, 0, str};
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    struct printf_spec ps = {
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    struct printf_spec ps = {(int(*)(void *, size_t, void *)) vsnprintf_write, &data};
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        (int(*)(void *, size_t, void *)) vsnprintf_write,
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        &data
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    };
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- 
 
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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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     * Print 0 at end of string - fix the case that nothing will be printed.
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     */
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    if (size > 0)
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    if (size > 0)
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        str[0] = 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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    /* vsnprintf_write ensures that str will be terminated by zero. */
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    return printf_core(fmt, &ps, ap);
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    return printf_core(fmt, &ps, ap);