text: ///////////////////////////////////////////////////////////////////////////////
  // \author (c) Marco Paland (info@paland.com)
  //             2014-2019, PALANDesign Hannover, Germany
  //
  // \license The MIT License (MIT)
  //
  // Permission is hereby granted, free of charge, to any person obtaining a copy
  // of this software and associated documentation files (the "Software"), to deal
  // in the Software without restriction, including without limitation the rights
  // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  // copies of the Software, and to permit persons to whom the Software is
  // furnished to do so, subject to the following conditions:
  //
  // The above copyright notice and this permission notice shall be included in
  // all copies or substantial portions of the Software.
  //
  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  // THE SOFTWARE.
  //
  // \brief Tiny printf, sprintf and (v)snprintf implementation, optimized for speed on
  //        embedded systems with a very limited resources. These routines are thread
  //        safe and reentrant!
  //        Use this instead of the bloated standard/newlib printf cause these use
  //        malloc for printf (and may not be thread safe).
  //
  ///////////////////////////////////////////////////////////////////////////////
  
  
  #include <mc/stdarg.h>
  #include <mc/stdio.h>
  
  
  // define this globally (e.g. gcc -DPRINTF_INCLUDE_CONFIG_H ...) to include the
  // printf_config.h header file
  // default: undefined
  #ifdef PRINTF_INCLUDE_CONFIG_H
  #include "printf_config.h"
  #endif
  
  
  // 'ntoa' conversion buffer size, this must be big enough to hold one converted
  // numeric number including padded zeros (dynamically created on stack)
  // default: 32 byte
  #ifndef PRINTF_NTOA_BUFFER_SIZE
  #define PRINTF_NTOA_BUFFER_SIZE    32U
  #endif
  
  // 'ftoa' conversion buffer size, this must be big enough to hold one converted
  // float number including padded zeros (dynamically created on stack)
  // default: 32 byte
  #ifndef PRINTF_FTOA_BUFFER_SIZE
  #define PRINTF_FTOA_BUFFER_SIZE    32U
  #endif
  
  // support for the floating point type (%f)
  // default: activated
  #ifndef PRINTF_DISABLE_SUPPORT_FLOAT
  #define PRINTF_SUPPORT_FLOAT
  #endif
  
  // support for exponential floating point notation (%e/%g)
  // default: activated
  #ifndef PRINTF_DISABLE_SUPPORT_EXPONENTIAL
  #define PRINTF_SUPPORT_EXPONENTIAL
  #endif
  
  // define the default floating point precision
  // default: 6 digits
  #ifndef PRINTF_DEFAULT_FLOAT_PRECISION
  #define PRINTF_DEFAULT_FLOAT_PRECISION  6U
  #endif
  
  // define the largest float suitable to print with %f
  // default: 1e9
  #ifndef PRINTF_MAX_FLOAT
  #define PRINTF_MAX_FLOAT  1e9
  #endif
  
  // support for the long long types (%llu or %p)
  // default: activated
  #ifndef PRINTF_DISABLE_SUPPORT_LONG_LONG
  #define PRINTF_SUPPORT_LONG_LONG
  #endif
  
  // support for the ptrdiff_t type (%t)
  // ptrdiff_t is normally defined in <stddef.h> as long or long long type
  // default: activated
  #ifndef PRINTF_DISABLE_SUPPORT_PTRDIFF_T
  #define PRINTF_SUPPORT_PTRDIFF_T
  #endif
  
  ///////////////////////////////////////////////////////////////////////////////
  
  // internal flag definitions
  #define FLAGS_ZEROPAD   (1U <<  0U)
  #define FLAGS_LEFT      (1U <<  1U)
  #define FLAGS_PLUS      (1U <<  2U)
  #define FLAGS_SPACE     (1U <<  3U)
  #define FLAGS_HASH      (1U <<  4U)
  #define FLAGS_UPPERCASE (1U <<  5U)
  #define FLAGS_CHAR      (1U <<  6U)
  #define FLAGS_SHORT     (1U <<  7U)
  #define FLAGS_LONG      (1U <<  8U)
  #define FLAGS_LONG_LONG (1U <<  9U)
  #define FLAGS_PRECISION (1U << 10U)
  #define FLAGS_ADAPT_EXP (1U << 11U)
  
  
  // import float.h for DBL_MAX
  #if defined(PRINTF_SUPPORT_FLOAT)
  //#include <mc/float.h>
  #endif
  
  
  struct printf_wrapper;
  
  // output function type
  typedef void (*out_fct_type)(struct printf_wrapper *wrapper, CHAR_TYPE character);
  
  
  // wrapper (used as buffer) for output function type
  struct printf_wrapper
  {
    out_fct_type out;
    cprintf_callback_t callback;
    void* arg;
    CHAR_TYPE *buffer;
    size_t idx;
    size_t maxlen;
  };
  
  
  // internal buffer output
  static inline void _out_buffer(struct printf_wrapper *wrapper, CHAR_TYPE character)
  {
    if (wrapper->idx < wrapper->maxlen)
      wrapper->buffer[wrapper->idx] = character;
    else
    if (character == 0)
      wrapper->buffer[wrapper->maxlen-1] = 0;
    wrapper->idx++;
  }
  
  
  // internal null output
  static inline void _out_null(struct printf_wrapper *wrapper, CHAR_TYPE character)
  {
    (void)character;
    wrapper->idx++;
  }
  
  
  // internal _putchar wrapper
  static inline void _out_char(struct printf_wrapper *wrapper, CHAR_TYPE character)
  {
    (void) wrapper;
    if (character) _putchar(character);
    wrapper->idx++;
  }
  
  
  // internal output function wrapper
  static inline void _out_fct(struct printf_wrapper *wrapper, CHAR_TYPE character)
  {
    if (character) wrapper->callback(character, wrapper->arg);
    wrapper->idx++;
  }
  
  
  // internal secure strlen
  // \return The length of the string (excluding the terminating 0) limited by 'maxsize'
  static inline unsigned int _strnlen_s(const CHAR_TYPE* str, size_t maxsize)
  {
    const CHAR_TYPE* s;
    for (s = str; *s && maxsize--; ++s);
    return (unsigned int)(s - str);
  }
  
  
  static inline unsigned int _strnlen_zs(const char* str, size_t maxsize)
  {
    const char* s;
    for (s = str; *s && maxsize--; ++s);
    return (unsigned int)(s - str);
  }
  
  
  // internal test if CHAR_TYPE is a digit (0-9)
  // \return true if CHAR_TYPE is a digit
  static inline bool _is_digit(CHAR_TYPE ch)
  {
    return (ch >= '0') && (ch <= '9');
  }
  
  
  // internal ASCII string to unsigned int conversion
  static unsigned int _atoi(const CHAR_TYPE** str)
  {
    unsigned int i = 0U;
    while (_is_digit(**str)) {
      i = i * 10U + (unsigned int)(*((*str)++) - '0');
    }
    return i;
  }
  
  
  // output the specified string in reverse, taking care of any zero-padding
  static void _out_rev(struct printf_wrapper *wrapper, const CHAR_TYPE* buf, size_t len, unsigned int width, unsigned int flags)
  {
    const size_t start_idx = wrapper->idx;
  
    // pad spaces up to given width
    if (!(flags & FLAGS_LEFT) && !(flags & FLAGS_ZEROPAD)) {
      for (size_t i = len; i < width; i++) {
        wrapper->out(wrapper, ' ');
      }
    }
  
    // reverse string
    while (len) {
      wrapper->out(wrapper, buf[--len]);
    }
  
    // append pad spaces up to given width
    if (flags & FLAGS_LEFT) {
      while (wrapper->idx - start_idx < width) {
        wrapper->out(wrapper, ' ');
      }
    }
  }
  
  
  // internal itoa format
  static void _ntoa_format(struct printf_wrapper *wrapper, CHAR_TYPE* buf, size_t len, bool negative, unsigned int base, unsigned int prec, unsigned int width, unsigned int flags)
  {
    // pad leading zeros
    if (!(flags & FLAGS_LEFT)) {
      if (width && (flags & FLAGS_ZEROPAD) && (negative || (flags & (FLAGS_PLUS | FLAGS_SPACE)))) {
        width--;
      }
      while ((len < prec) && (len < PRINTF_NTOA_BUFFER_SIZE)) {
        buf[len++] = '0';
      }
      while ((flags & FLAGS_ZEROPAD) && (len < width) && (len < PRINTF_NTOA_BUFFER_SIZE)) {
        buf[len++] = '0';
      }
    }
  
    // handle hash
    if (flags & FLAGS_HASH) {
      if (!(flags & FLAGS_PRECISION) && len && ((len == prec) || (len == width))) {
        len--;
        if (len && (base == 16U)) {
          len--;
        }
      }
      if ((base == 16U) && !(flags & FLAGS_UPPERCASE) && (len < PRINTF_NTOA_BUFFER_SIZE)) {
        buf[len++] = 'x';
      }
      else if ((base == 16U) && (flags & FLAGS_UPPERCASE) && (len < PRINTF_NTOA_BUFFER_SIZE)) {
        buf[len++] = 'X';
      }
      else if ((base == 2U) && (len < PRINTF_NTOA_BUFFER_SIZE)) {
        buf[len++] = 'b';
      }
      if (len < PRINTF_NTOA_BUFFER_SIZE) {
        buf[len++] = '0';
      }
    }
  
    if (len < PRINTF_NTOA_BUFFER_SIZE) {
      if (negative) {
        buf[len++] = '-';
      }
      else if (flags & FLAGS_PLUS) {
        buf[len++] = '+';  // ignore the space if the '+' exists
      }
      else if (flags & FLAGS_SPACE) {
        buf[len++] = ' ';
      }
    }
  
    _out_rev(wrapper, buf, len, width, flags);
  }
  
  
  // internal itoa for 'long' type
  static void _ntoa_long(struct printf_wrapper *wrapper, unsigned long value, bool negative, unsigned long base, unsigned int prec, unsigned int width, unsigned int flags)
  {
    CHAR_TYPE buf[PRINTF_NTOA_BUFFER_SIZE];
    size_t len = 0U;
  
    // no hash for 0 values
    if (!value) {
      flags &= ~FLAGS_HASH;
    }
  
    // write if precision != 0 and value is != 0
    if (!(flags & FLAGS_PRECISION) || value) {
      do {
        const CHAR_TYPE digit = (CHAR_TYPE)(value % base);
        buf[len++] = (CHAR_TYPE) ((digit < 10) ? '0' + digit : (flags & FLAGS_UPPERCASE ? 'A' : 'a') + digit - 10);
        value /= base;
      } while (value && (len < PRINTF_NTOA_BUFFER_SIZE));
    }
  
    _ntoa_format(wrapper, buf, len, negative, (unsigned int)base, prec, width, flags);
  }
  
  
  // internal itoa for 'long long' type
  #if defined(PRINTF_SUPPORT_LONG_LONG)
  static void _ntoa_long_long(struct printf_wrapper *wrapper, unsigned long long value, bool negative, unsigned long long base, unsigned int prec, unsigned int width, unsigned int flags)
  {
    CHAR_TYPE buf[PRINTF_NTOA_BUFFER_SIZE];
    size_t len = 0U;
  
    // no hash for 0 values
    if (!value) {
      flags &= ~FLAGS_HASH;
    }
  
    // write if precision != 0 and value is != 0
    if (!(flags & FLAGS_PRECISION) || value) {
      do {
        const CHAR_TYPE digit = (CHAR_TYPE)(value % base);
        buf[len++] = (CHAR_TYPE)  ((digit < 10) ? '0' + digit : (flags & FLAGS_UPPERCASE ? 'A' : 'a') + digit - 10);
        value /= base;
      } while (value && (len < PRINTF_NTOA_BUFFER_SIZE));
    }
  
    _ntoa_format(wrapper, buf, len, negative, (unsigned int)base, prec, width, flags);
  }
  #endif  // PRINTF_SUPPORT_LONG_LONG
  
  
  #if defined(PRINTF_SUPPORT_FLOAT)
  
  #if defined(PRINTF_SUPPORT_EXPONENTIAL)
  // forward declaration so that _ftoa can switch to exp notation for values > PRINTF_MAX_FLOAT
  static void _etoa(struct printf_wrapper *wrapper, double value, unsigned int prec, unsigned int width, unsigned int flags);
  #endif
  
  
  // internal ftoa for fixed decimal floating point
  static void _ftoa(struct printf_wrapper *wrapper, double value, unsigned int prec, unsigned int width, unsigned int flags)
  {
    CHAR_TYPE buf[PRINTF_FTOA_BUFFER_SIZE];
    size_t len  = 0U;
    double diff = 0.0;
  
    // powers of 10
    static const uint32_t pow10[] = { 1, 10, 100, 1000, 10000, 100000, 1000000, 10000000, 100000000, 1000000000 };
  
    // test for special values
    if (value != value)
    {
      _out_rev(wrapper, "nan", 3, width, flags);
      return;
    }
    if (value < -DBL_MAX)
    {
      _out_rev(wrapper, "fni-", 4, width, flags);
      return;
    }
    if (value > DBL_MAX)
    {
      _out_rev(wrapper, (flags & FLAGS_PLUS) ? "fni+" : "fni", (flags & FLAGS_PLUS) ? 4U : 3U, width, flags);
      return;
    }
  
    // test for very large values
    // standard printf behavior is to print EVERY whole number digit -- which could be 100s of characters overflowing your buffers == bad
    if ((value > PRINTF_MAX_FLOAT) || (value < -PRINTF_MAX_FLOAT)) {
  #if defined(PRINTF_SUPPORT_EXPONENTIAL)
      _etoa(wrapper, value, prec, width, flags);
      return;
  #else
      return;
  #endif
    }
  
    // test for negative
    bool negative = false;
    if (value < 0) {
      negative = true;
      value = 0 - value;
    }
  
    // set default precision, if not set explicitly
    if (!(flags & FLAGS_PRECISION)) {
      prec = PRINTF_DEFAULT_FLOAT_PRECISION;
    }
    // limit precision to 9, cause a prec >= 10 can lead to overflow errors
    while ((len < PRINTF_FTOA_BUFFER_SIZE) && (prec > 9U)) {
      buf[len++] = '0';
      prec--;
    }
  
    int whole = (int)value;
    double tmp = (value - whole) * pow10[prec];
    uint32_t frac = (uint32_t)tmp;
    diff = tmp - frac;
  
    if (diff > 0.5) {
      ++frac;
      // handle rollover, e.g. case 0.99 with prec 1 is 1.0
      if (frac >= pow10[prec]) {
        frac = 0;
        ++whole;
      }
    }
    else if (diff < 0.5) {
    }
    else if ((frac == 0U) || (frac & 1U)) {
      // if halfway, round up if odd OR if last digit is 0
      ++frac;
    }
  
    if (prec == 0U) {
      diff = value - (double)whole;
      if ((!(diff < 0.5) || (diff > 0.5)) && (whole & 1)) {
        // exactly 0.5 and ODD, then round up
        // 1.5 -> 2, but 2.5 -> 2
        ++whole;
      }
    }
    else {
      unsigned int count = prec;
      // now do fractional part, as an unsigned number
      while (len < PRINTF_FTOA_BUFFER_SIZE) {
        --count;
        buf[len++] = (CHAR_TYPE)(48U + (frac % 10U));
        if (!(frac /= 10U)) {
          break;
        }
      }
      // add extra 0s
      while ((len < PRINTF_FTOA_BUFFER_SIZE) && (count-- > 0U)) {
        buf[len++] = '0';
      }
      if (len < PRINTF_FTOA_BUFFER_SIZE) {
        // add decimal
        buf[len++] = '.';
      }
    }
  
    // do whole part, number is reversed
    while (len < PRINTF_FTOA_BUFFER_SIZE) {
      buf[len++] = (CHAR_TYPE)(48 + (whole % 10));
      if (!(whole /= 10)) {
        break;
      }
    }
  
    // pad leading zeros
    if (!(flags & FLAGS_LEFT) && (flags & FLAGS_ZEROPAD)) {
      if (width && (negative || (flags & (FLAGS_PLUS | FLAGS_SPACE)))) {
        width--;
      }
      while ((len < width) && (len < PRINTF_FTOA_BUFFER_SIZE)) {
        buf[len++] = '0';
      }
    }
  
    if (len < PRINTF_FTOA_BUFFER_SIZE) {
      if (negative) {
        buf[len++] = '-';
      }
      else if (flags & FLAGS_PLUS) {
        buf[len++] = '+';  // ignore the space if the '+' exists
      }
      else if (flags & FLAGS_SPACE) {
        buf[len++] = ' ';
      }
    }
  
    _out_rev(wrapper, buf, len, width, flags);
  }
  
  
  #if defined(PRINTF_SUPPORT_EXPONENTIAL)
  // internal ftoa variant for exponential floating-point type, contributed by Martijn Jasperse <m.jasperse@gmail.com>
  static void _etoa(struct printf_wrapper *wrapper, double value, unsigned int prec, unsigned int width, unsigned int flags)
  {
    // check for NaN and special values
    if ((value != value) || (value > DBL_MAX) || (value < -DBL_MAX)) {
      _ftoa(wrapper, value, prec, width, flags);
      return;
    }
  
    // determine the sign
    const bool negative = value < 0;
    if (negative) {
      value = -value;
    }
  
    // default precision
    if (!(flags & FLAGS_PRECISION)) {
      prec = PRINTF_DEFAULT_FLOAT_PRECISION;
    }
  
    // determine the decimal exponent
    // based on the algorithm by David Gay (https://www.ampl.com/netlib/fp/dtoa.c)
    union {
      uint64_t U;
      double   F;
    } conv;
  
    conv.F = value;
    int exp2 = (int)((conv.U >> 52U) & 0x07FFU) - 1023;           // effectively log2
    conv.U = (conv.U & ((1ULL << 52U) - 1U)) | (1023ULL << 52U);  // drop the exponent so conv.F is now in [1,2)
    // now approximate log10 from the log2 integer part and an expansion of ln around 1.5
    int expval = (int)(0.1760912590558 + exp2 * 0.301029995663981 + (conv.F - 1.5) * 0.289529654602168);
    // now we want to compute 10^expval but we want to be sure it won't overflow
    exp2 = (int)(expval * 3.321928094887362 + 0.5);
    const double z  = expval * 2.302585092994046 - exp2 * 0.6931471805599453;
    const double z2 = z * z;
    conv.U = (uint64_t)(exp2 + 1023) << 52U;
    // compute exp(z) using continued fractions, see https://en.wikipedia.org/wiki/Exponential_function#Continued_fractions_for_ex
    conv.F *= 1 + 2 * z / (2 - z + (z2 / (6 + (z2 / (10 + z2 / 14)))));
    // correct for rounding errors
    if (value < conv.F) {
      expval--;
      conv.F /= 10;
    }
  
    // the exponent format is "%+03d" and largest value is "307", so set aside 4-5 characters
    unsigned int minwidth = ((expval < 100) && (expval > -100)) ? 4U : 5U;
  
    // in "%g" mode, "prec" is the number of *significant figures* not decimals
    if (flags & FLAGS_ADAPT_EXP) {
      // do we want to fall-back to "%f" mode?
      if ((value >= 1e-4) && (value < 1e6)) {
        if ((int)prec > expval) {
          prec = (unsigned)((int)prec - expval - 1);
        }
        else {
          prec = 0;
        }
        flags |= FLAGS_PRECISION;   // make sure _ftoa respects precision
        // no characters in exponent
        minwidth = 0U;
        expval   = 0;
      }
      else {
        // we use one sigfig for the whole part
        if ((prec > 0) && (flags & FLAGS_PRECISION)) {
          --prec;
        }
      }
    }
  
    // will everything fit?
    unsigned int fwidth = width;
    if (width > minwidth) {
      // we didn't fall-back so subtract the characters required for the exponent
      fwidth -= minwidth;
    } else {
      // not enough characters, so go back to default sizing
      fwidth = 0U;
    }
    if ((flags & FLAGS_LEFT) && minwidth) {
      // if we're padding on the right, DON'T pad the floating part
      fwidth = 0U;
    }
  
    // rescale the float value
    if (expval) {
      value /= conv.F;
    }
  
    // output the floating part
    const size_t start_idx = wrapper->idx;
    _ftoa(wrapper, negative ? -value : value, prec, fwidth, flags & ~FLAGS_ADAPT_EXP);
  
    // output the exponent part
    if (minwidth) {
      // output the exponential symbol
      wrapper->out(wrapper, (flags & FLAGS_UPPERCASE) ? 'E' : 'e');
      // output the exponent value
      _ntoa_long(wrapper, (unsigned long) ((expval < 0) ? -expval : expval), expval < 0, 10, 0, minwidth-1, FLAGS_ZEROPAD | FLAGS_PLUS);
      // might need to right-pad spaces
      if (flags & FLAGS_LEFT) {
        while (wrapper->idx - start_idx < width) wrapper->out(wrapper, ' ');
      }
    }
  }
  #endif  // PRINTF_SUPPORT_EXPONENTIAL
  #endif  // PRINTF_SUPPORT_FLOAT
  
  
  // internal vsnprintf
  static int _vsnprintf(/*out_fct_type out, CHAR_TYPE* buffer, const size_t maxlen*/struct printf_wrapper *wrapper, const CHAR_TYPE* format, va_list va)
  {
    unsigned int flags, width, precision, n;
    //size_t idx = 0U;
  
    if (wrapper->buffer == NULL && wrapper->callback == NULL && wrapper->out != _out_char) wrapper->out = _out_null;
  
    while (*format)
    {
      // format specifier?  %[flags][width][.precision][length]
      if (*format != '%') {
        // no
        wrapper->out(wrapper, *format);
        format++;
        continue;
      }
      else {
        // yes, evaluate it
        format++;
      }
  
      // evaluate flags
      flags = 0U;
      do {
        switch (*format) {
          case '0': flags |= FLAGS_ZEROPAD; format++; n = 1U; break;
          case '-': flags |= FLAGS_LEFT;    format++; n = 1U; break;
          case '+': flags |= FLAGS_PLUS;    format++; n = 1U; break;
          case ' ': flags |= FLAGS_SPACE;   format++; n = 1U; break;
          case '#': flags |= FLAGS_HASH;    format++; n = 1U; break;
          default :                                   n = 0U; break;
        }
      } while (n);
  
      // evaluate width field
      width = 0U;
      if (_is_digit(*format)) {
        width = _atoi(&format);
      }
      else if (*format == '*') {
        const int w = va_arg(va, int);
        if (w < 0) {
          flags |= FLAGS_LEFT;    // reverse padding
          width = (unsigned int)-w;
        }
        else {
          width = (unsigned int)w;
        }
        format++;
      }
  
      // evaluate precision field
      precision = 0U;
      if (*format == '.') {
        flags |= FLAGS_PRECISION;
        format++;
        if (_is_digit(*format)) {
          precision = _atoi(&format);
        }
        else if (*format == '*') {
          const int prec = (int)va_arg(va, int);
          precision = prec > 0 ? (unsigned int)prec : 0U;
          format++;
        }
      }
  
      // evaluate length field
      switch (*format) {
        case 'l' :
          flags |= FLAGS_LONG;
          format++;
          if (*format == 'l') {
            flags |= FLAGS_LONG_LONG;
            format++;
          }
          break;
        case 'h' :
          flags |= FLAGS_SHORT;
          format++;
          if (*format == 'h') {
            flags |= FLAGS_CHAR;
            format++;
          }
          break;
  #if defined(PRINTF_SUPPORT_PTRDIFF_T)
        case 't' :
          flags |= (sizeof(ptrdiff_t) == sizeof(long) ? FLAGS_LONG : FLAGS_LONG_LONG);
          format++;
          break;
  #endif
        case 'j' :
          flags |= (sizeof(intmax_t) == sizeof(long) ? FLAGS_LONG : FLAGS_LONG_LONG);
          format++;
          break;
        case 'z' :
          flags |= (sizeof(size_t) == sizeof(long) ? FLAGS_LONG : FLAGS_LONG_LONG);
          format++;
          break;
        default :
          break;
      }
  
      // evaluate specifier
      switch (*format) {
        case 'd' :
        case 'i' :
        case 'u' :
        case 'x' :
        case 'X' :
        case 'o' :
        case 'b' : {
          // set the base
          unsigned int base;
          if (*format == 'x' || *format == 'X') {
            base = 16U;
          }
          else if (*format == 'o') {
            base =  8U;
          }
          else if (*format == 'b') {
            base =  2U;
          }
          else {
            base = 10U;
            flags &= ~FLAGS_HASH;   // no hash for dec format
          }
          // uppercase
          if (*format == 'X') {
            flags |= FLAGS_UPPERCASE;
          }
  
          // no plus or space flag for u, x, X, o, b
          if ((*format != 'i') && (*format != 'd')) {
            flags &= ~(FLAGS_PLUS | FLAGS_SPACE);
          }
  
          // ignore '0' flag when precision is given
          if (flags & FLAGS_PRECISION) {
            flags &= ~FLAGS_ZEROPAD;
          }
  
          // convert the integer
          if ((*format == 'i') || (*format == 'd')) {
            // signed
            if (flags & FLAGS_LONG_LONG) {
  #if defined(PRINTF_SUPPORT_LONG_LONG)
              const long long value = va_arg(va, long long);
              _ntoa_long_long(wrapper, (unsigned long long)(value > 0 ? value : 0 - value), value < 0, base, precision, width, flags);
  #endif
            }
            else if (flags & FLAGS_LONG) {
              const long value = va_arg(va, long);
              _ntoa_long(wrapper, (unsigned long)(value > 0 ? value : 0 - value), value < 0, base, precision, width, flags);
            }
            else {
              const int value = (flags & FLAGS_CHAR) ? (CHAR_TYPE)va_arg(va, int) : (flags & FLAGS_SHORT) ? (short int)va_arg(va, int) : va_arg(va, int);
              _ntoa_long(wrapper, (unsigned int)(value > 0 ? value : 0 - value), value < 0, base, precision, width, flags);
            }
          }
          else {
            // unsigned
            if (flags & FLAGS_LONG_LONG) {
  #if defined(PRINTF_SUPPORT_LONG_LONG)
              _ntoa_long_long(wrapper, va_arg(va, unsigned long long), false, base, precision, width, flags);
  #endif
            }
            else if (flags & FLAGS_LONG) {
              _ntoa_long(wrapper, va_arg(va, unsigned long), false, base, precision, width, flags);
            }
            else {
              const unsigned int value = (flags & FLAGS_CHAR) ? (UCHAR_TYPE)va_arg(va, unsigned int) : (flags & FLAGS_SHORT) ? (unsigned short int)va_arg(va, unsigned int) : va_arg(va, unsigned int);
              _ntoa_long(wrapper, value, false, base, precision, width, flags);
            }
          }
          format++;
          break;
        }
  #if defined(PRINTF_SUPPORT_FLOAT)
        case 'f' :
        case 'F' :
          if (*format == 'F') flags |= FLAGS_UPPERCASE;
          _ftoa(wrapper, va_arg(va, double), precision, width, flags);
          format++;
          break;
  #if defined(PRINTF_SUPPORT_EXPONENTIAL)
        case 'e':
        case 'E':
        case 'g':
        case 'G':
          if ((*format == 'g')||(*format == 'G')) flags |= FLAGS_ADAPT_EXP;
          if ((*format == 'E')||(*format == 'G')) flags |= FLAGS_UPPERCASE;
          _etoa(wrapper, va_arg(va, double), precision, width, flags);
          format++;
          break;
  #endif  // PRINTF_SUPPORT_EXPONENTIAL
  #endif  // PRINTF_SUPPORT_FLOAT
        case 'c' : {
          unsigned int l = 1U;
          // pre padding
          if (!(flags & FLAGS_LEFT)) {
            while (l++ < width) {
              wrapper->out(wrapper, ' ');
            }
          }
          // CHAR_TYPE output
          wrapper->out(wrapper, (CHAR_TYPE)va_arg(va, int));
          // post padding
          if (flags & FLAGS_LEFT) {
            while (l++ < width) {
              wrapper->out(wrapper, ' ');
            }
          }
          format++;
          break;
        }
  
        case 'S' : {
          const char* p = va_arg(va, char*);
          unsigned int l = _strnlen_zs(p, precision ? precision : (size_t)-1);
          // pre padding
          if (flags & FLAGS_PRECISION) {
            l = (l < precision ? l : precision);
          }
          if (!(flags & FLAGS_LEFT)) {
            while (l++ < width) {
              wrapper->out(wrapper, ' ');
            }
          }
          // string output
          while ((*p != 0) && (!(flags & FLAGS_PRECISION) || precision--)) {
            wrapper->out(wrapper, (CHAR_TYPE) *(p++));
          }
          // post padding
          if (flags & FLAGS_LEFT) {
            while (l++ < width) {
              wrapper->out(wrapper, ' ');
            }
          }
          format++;
          break;
        }
  
        case 's' : {
          const CHAR_TYPE* p = va_arg(va, CHAR_TYPE*);
          unsigned int l = _strnlen_s(p, precision ? precision : (size_t)-1);
          // pre padding
          if (flags & FLAGS_PRECISION) {
            l = (l < precision ? l : precision);
          }
          if (!(flags & FLAGS_LEFT)) {
            while (l++ < width) {
              wrapper->out(wrapper, ' ');
            }
          }
          // string output
          while ((*p != 0) && (!(flags & FLAGS_PRECISION) || precision--)) {
            wrapper->out(wrapper, *(p++));
          }
          // post padding
          if (flags & FLAGS_LEFT) {
            while (l++ < width) {
              wrapper->out(wrapper, ' ');
            }
          }
          format++;
          break;
        }
  
        case 'p' : {
          width = sizeof(void*) * 2U;
          flags |= FLAGS_ZEROPAD | FLAGS_UPPERCASE;
  #if defined(PRINTF_SUPPORT_LONG_LONG)
          const bool is_ll = sizeof(uintptr_t) == sizeof(long long);
          if (is_ll) {
            _ntoa_long_long(wrapper, (uintptr_t)va_arg(va, void*), false, 16U, precision, width, flags);
          }
          else {
  #endif
            _ntoa_long(wrapper, (unsigned long)((uintptr_t)va_arg(va, void*)), false, 16U, precision, width, flags);
  #if defined(PRINTF_SUPPORT_LONG_LONG)
          }
  #endif
          format++;
          break;
        }
  
        case '%' :
          wrapper->out(wrapper, '%');
          format++;
          break;
  
        default :
          wrapper->out(wrapper, *format);
          format++;
          break;
      }
    }
  
    // termination
    wrapper->out(wrapper, (CHAR_TYPE)0);
  
    // return written chars without terminating \0
    return (int)wrapper->idx - 1;
  }
  
  
  ///////////////////////////////////////////////////////////////////////////////
  
  int printf_(const CHAR_TYPE* format, ...)
  {
    va_list va;
    va_start(va, format);
    struct printf_wrapper wrapper = { _out_char, NULL, NULL, NULL, 0, 0 };
    const int ret = _vsnprintf(&wrapper, format, va);
    va_end(va);
    return ret;
  }
  
  
  int sprintf_(CHAR_TYPE* buffer, const CHAR_TYPE* format, ...)
  {
    va_list va;
    va_start(va, format);
    struct printf_wrapper wrapper = { _out_buffer, NULL, NULL, buffer, 0, (size_t)-1 };
    const int ret = _vsnprintf(&wrapper, format, va);
    va_end(va);
    return ret;
  }
  
  
  int snprintf_(CHAR_TYPE* buffer, size_t count, const CHAR_TYPE* format, ...)
  {
    va_list va;
    va_start(va, format);
    struct printf_wrapper wrapper = { _out_buffer, NULL, NULL, buffer, 0, count };
    const int ret = _vsnprintf(&wrapper, format, va);
    va_end(va);
    return ret;
  }
  
  
  int sncatprintf_(CHAR_TYPE* buffer, size_t count, const CHAR_TYPE* format, ...)
  {
    CHAR_TYPE *p = buffer;
  
    // move cursor to the end of the string
    while (*p != 0 && p < buffer + count) ++p;
    count = count - (size_t) (p - buffer);
  
    va_list va;
    va_start(va, format);
    struct printf_wrapper wrapper = { _out_buffer, NULL, NULL, p, 0, count };
    const int ret = _vsnprintf(&wrapper, format, va);
    va_end(va);
    return ret;
  }
  
  
  int vprintf_(const CHAR_TYPE* format, va_list va)
  {
    struct printf_wrapper wrapper = { _out_char, NULL, NULL, NULL, 0, 0 };
    return _vsnprintf(&wrapper, format, va);
  }
  
  
  int vsnprintf_(CHAR_TYPE* buffer, size_t count, const CHAR_TYPE* format, va_list va)
  {
    struct printf_wrapper wrapper = { _out_buffer, NULL, NULL, buffer, 0, count };
    return _vsnprintf(&wrapper, format, va);
  }
  
  
  int cprintf(cprintf_callback_t callback, void* arg, const CHAR_TYPE* format, ...)
  {
    va_list va;
    va_start(va, format);
    struct printf_wrapper wrapper = { _out_fct, callback, arg, NULL, 0, 0 };
    const int ret = _vsnprintf(&wrapper, format, va);
    va_end(va);
    return ret;
  }
  
  int puts_( const char *str )
  {
    while (*str) _putchar(*str++);
    return 0;
  }
  
  int puti( int32_t value )
  {
    return putl(value);
  }
  
  int putl( int64_t value )
  {
    CHAR_TYPE buf[PRINTF_NTOA_BUFFER_SIZE];
    int len = 0;
    do {
        const CHAR_TYPE digit = (CHAR_TYPE)(value % 10);
        buf[len++] = (CHAR_TYPE) ('0' + digit);
        value /= 10;
      } while (value && ((uint32_t)len + 1 < PRINTF_NTOA_BUFFER_SIZE));
      buf[len] = 0;
  
      while (len >= 0) _putchar(buf[len--]);
      return 0;
  }