Function vsnprintf

examples/stdlib.c:3909–4110

}

static int vsnprintf(char *str, size_t size, const char *format, va_list ap)
{
    size_t idx = 0;
    for (; *format != '\0'; format++)
    {
        if (*format != '%')
        {
            idx = printf_put_char(str, size, idx, *format);
            continue;
        }
        format++;
        unsigned flags = 0x0;
        for (; true; format++)
        {
            switch (*format)
            {
                case ' ':
                    flags |= PRINTF_FLAG_SPACE;
                    continue;
                case '+':
                    flags |= PRINTF_FLAG_PLUS;
                    continue;
                case '-':
                    if (!(flags & PRINTF_FLAG_ZERO))
                        flags |= PRINTF_FLAG_RIGHT;
                    continue;
                case '#':
                    flags |= PRINTF_FLAG_HASH;
                    continue;
                case '0':
                    flags &= ~PRINTF_FLAG_RIGHT;
                    flags |= PRINTF_FLAG_ZERO;
                    continue;
                default:
                    break;
            }
            break;
        }

        size_t width = 0;
        if (*format == '*')
        {
            format++;
            int tmp = va_arg(ap, int);
            if (tmp < 0)
            {
                flags |= (!(flags & PRINTF_FLAG_ZERO)? PRINTF_FLAG_RIGHT: 0);
                width = (size_t)-tmp;
            }
            else
                width = (size_t)tmp;
        }
        else
        {
            for (; isdigit(*format); format++)
            {
                width *= 10;
                width += (unsigned)(*format - '0');