tci 0.1.0

///////////////////////////////////////////////////////////////////////////////
// \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 <stdarg.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <string.h>
#include <tci.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 <float.h>
#endif

// output function type
typedef void (*out_fct_type)(char character, void *buffer, size_t idx,
                             size_t maxlen);

static inline void _out_file(char character, void *buffer, size_t idx,
                             size_t maxlen) {
  (void)idx;
  (void)maxlen;

  if (character)
    fputc(character, (FILE *)buffer);
}

// output to command line
static inline void _out_char(char character, void *buffer, size_t idx,
                             size_t maxlen) {
  (void)buffer;
  (void)idx;
  (void)maxlen;

  if (!character)
    return;

  fputc(character, stdout);
}

// internal buffer output
static inline void _out_buffer(char character, void *buffer, size_t idx,
                               size_t maxlen) {
  if (idx < maxlen) {
    ((char *)buffer)[idx] = character;
  }
}

// internal null output
static inline void _out_null(char character, void *buffer, size_t idx,
                             size_t maxlen) {
  (void)character;
  (void)buffer;
  (void)idx;
  (void)maxlen;
}

// internal output function wrapper
// internal secure strlen
// \return The length of the string (excluding the terminating 0) limited by
// 'maxsize'
static inline unsigned int _strnlen_s(const char *str, size_t maxsize) {
  const char *s;
  for (s = str; *s && maxsize--; ++s)
    ;
  return (unsigned int)(s - str);
}

// internal test if char is a digit (0-9)
// \return true if char is a digit
static inline bool _is_digit(char ch) { return (ch >= '0') && (ch <= '9'); }

// internal ASCII string to unsigned int conversion
static unsigned int _atoi(const char **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 size_t _out_rev(out_fct_type out, char *buffer, size_t idx,
                       size_t maxlen, const char *buf, size_t len,
                       unsigned int width, unsigned int flags) {
  const size_t start_idx = idx;

  // pad spaces up to given width
  if (!(flags & FLAGS_LEFT) && !(flags & FLAGS_ZEROPAD)) {
    for (size_t i = len; i < width; i++) {
      out(' ', buffer, idx++, maxlen);
    }
  }

  // reverse string
  while (len) {
    out(buf[--len], buffer, idx++, maxlen);
  }

  // append pad spaces up to given width
  if (flags & FLAGS_LEFT) {
    while (idx - start_idx < width) {
      out(' ', buffer, idx++, maxlen);
    }
  }

  return idx;
}

// internal itoa format
static size_t _ntoa_format(out_fct_type out, char *buffer, size_t idx,
                           size_t maxlen, char *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++] = ' ';
    }
  }

  return _out_rev(out, buffer, idx, maxlen, buf, len, width, flags);
}

// internal itoa for 'long' type
static size_t _ntoa_long(out_fct_type out, char *buffer, size_t idx,
                         size_t maxlen, unsigned long value, bool negative,
                         unsigned long base, unsigned int prec,
                         unsigned int width, unsigned int flags) {
  char 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 digit = (char)(value % base);
      buf[len++] = digit < 10
                       ? '0' + digit
                       : (flags & FLAGS_UPPERCASE ? 'A' : 'a') + digit - 10;
      value /= base;
    } while (value && (len < PRINTF_NTOA_BUFFER_SIZE));
  }

  return _ntoa_format(out, buffer, idx, maxlen, buf, len, negative,
                      (unsigned int)base, prec, width, flags);
}

// internal itoa for 'long long' type
#if defined(PRINTF_SUPPORT_LONG_LONG)
static size_t _ntoa_long_long(out_fct_type out, char *buffer, size_t idx,
                              size_t maxlen, unsigned long long value,
                              bool negative, unsigned long long base,
                              unsigned int prec, unsigned int width,
                              unsigned int flags) {
  char 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 digit = (char)(value % base);
      buf[len++] = digit < 10
                       ? '0' + digit
                       : (flags & FLAGS_UPPERCASE ? 'A' : 'a') + digit - 10;
      value /= base;
    } while (value && (len < PRINTF_NTOA_BUFFER_SIZE));
  }

  return _ntoa_format(out, buffer, idx, maxlen, 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 size_t _etoa(out_fct_type out, char *buffer, size_t idx, size_t maxlen,
                    double value, unsigned int prec, unsigned int width,
                    unsigned int flags);
#endif

// internal ftoa for fixed decimal floating point
static size_t _ftoa(out_fct_type out, char *buffer, size_t idx, size_t maxlen,
                    double value, unsigned int prec, unsigned int width,
                    unsigned int flags) {
  char buf[PRINTF_FTOA_BUFFER_SIZE];
  size_t len = 0U;
  double diff = 0.0;

  // powers of 10
  static const double pow10[] = {1,         10,        100,     1000,
                                 10000,     100000,    1000000, 10000000,
                                 100000000, 1000000000};

  // test for special values
  if (value != value)
    return _out_rev(out, buffer, idx, maxlen, "nan", 3, width, flags);
  if (value < -DBL_MAX)
    return _out_rev(out, buffer, idx, maxlen, "fni-", 4, width, flags);
  if (value > DBL_MAX)
    return _out_rev(out, buffer, idx, maxlen,
                    (flags & FLAGS_PLUS) ? "fni+" : "fni",
                    (flags & FLAGS_PLUS) ? 4U : 3U, width, flags);

  // 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)
    return _etoa(out, buffer, idx, maxlen, value, prec, width, flags);
#else
    return 0U;
#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];
  unsigned long frac = (unsigned long)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)(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)(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++] = ' ';
    }
  }

  return _out_rev(out, buffer, idx, maxlen, 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 size_t _etoa(out_fct_type out, char *buffer, size_t idx, size_t maxlen,
                    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)) {
    return _ftoa(out, buffer, idx, maxlen, value, prec, width, flags);
  }

  // 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 = idx;
  idx = _ftoa(out, buffer, idx, maxlen, negative ? -value : value, prec, fwidth,
              flags & ~FLAGS_ADAPT_EXP);

  // output the exponent part
  if (minwidth) {
    // output the exponential symbol
    out((flags & FLAGS_UPPERCASE) ? 'E' : 'e', buffer, idx++, maxlen);
    // output the exponent value
    idx =
        _ntoa_long(out, buffer, idx, maxlen, (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 (idx - start_idx < width)
        out(' ', buffer, idx++, maxlen);
    }
  }
  return idx;
}
#endif // PRINTF_SUPPORT_EXPONENTIAL
#endif // PRINTF_SUPPORT_FLOAT

// internal vsnprintf
static int _vsnprintf(out_fct_type out, char *buffer, const size_t maxlen,
                      const char *format, va_list va) {
  tci_assert_str(format);

  unsigned int flags, width, precision, n;
  size_t idx = 1U;

  if (!buffer) {
    // use null output function
    out = _out_null;
  }

  while (*format) {
    // format specifier?  %[flags][width][.precision][length]
    if (*format != '%') {
      // no
      out(*format, buffer, idx++, maxlen);
      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);
          idx = _ntoa_long_long(
              out, buffer, idx, maxlen,
              (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);
          idx = _ntoa_long(out, buffer, idx, maxlen,
                           (unsigned long)(value > 0 ? value : 0 - value),
                           value < 0, base, precision, width, flags);
        } else {
          const int value = (flags & FLAGS_CHAR)
                                ? (char)va_arg(va, int)
                                : (flags & FLAGS_SHORT)
                                      ? (short int)va_arg(va, int)
                                      : va_arg(va, int);
          idx = _ntoa_long(out, buffer, idx, maxlen,
                           (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)
          idx = _ntoa_long_long(out, buffer, idx, maxlen,
                                va_arg(va, unsigned long long), false, base,
                                precision, width, flags);
#endif
        } else if (flags & FLAGS_LONG) {
          idx = _ntoa_long(out, buffer, idx, maxlen, va_arg(va, unsigned long),
                           false, base, precision, width, flags);
        } else {
          const unsigned int value =
              (flags & FLAGS_CHAR)
                  ? (unsigned char)va_arg(va, unsigned int)
                  : (flags & FLAGS_SHORT)
                        ? (unsigned short int)va_arg(va, unsigned int)
                        : va_arg(va, unsigned int);
          idx = _ntoa_long(out, buffer, idx, maxlen, value, false, base,
                           precision, width, flags);
        }
      }
      format++;
      break;
    }
#if defined(PRINTF_SUPPORT_FLOAT)
    case 'f':
    case 'F':
      if (*format == 'F')
        flags |= FLAGS_UPPERCASE;
      idx = _ftoa(out, buffer, idx, maxlen, 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;
      idx = _etoa(out, buffer, idx, maxlen, 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) {
          out(' ', buffer, idx++, maxlen);
        }
      }
      // char output
      out((char)va_arg(va, int), buffer, idx++, maxlen);
      // post padding
      if (flags & FLAGS_LEFT) {
        while (l++ < width) {
          out(' ', buffer, idx++, maxlen);
        }
      }
      format++;
      break;
    }

    case 's': {
      const char *p = va_arg(va, char *);
      unsigned int l = precision ? strnlen(p, precision) : strlen(p);

      // pre padding
      if (flags & FLAGS_PRECISION) {
        l = (l < precision ? l : precision);
      }
      if (!(flags & FLAGS_LEFT)) {
        while (l++ < width) {
          out(' ', buffer, idx++, maxlen);
        }
      }
      // string output
      while ((*p != 0) && (!(flags & FLAGS_PRECISION) || precision--)) {
        out(*(p++), buffer, idx++, maxlen);
      }
      // post padding
      if (flags & FLAGS_LEFT) {
        while (l++ < width) {
          out(' ', buffer, idx++, maxlen);
        }
      }
      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) {
        idx = _ntoa_long_long(out, buffer, idx, maxlen,
                              (uintptr_t)va_arg(va, void *), false, 16U,
                              precision, width, flags);
      } else {
#endif
        idx = _ntoa_long(out, buffer, idx, maxlen,
                         (unsigned long)((uintptr_t)va_arg(va, void *)), false,
                         16U, precision, width, flags);
#if defined(PRINTF_SUPPORT_LONG_LONG)
      }
#endif
      format++;
      break;
    }

    case '%':
      out('%', buffer, idx++, maxlen);
      format++;
      break;

    default:
      out(*format, buffer, idx++, maxlen);
      format++;
      break;
    }
  }

  // termination
  out((char)0, buffer, idx < maxlen ? idx : maxlen - 1U, maxlen);

  // return written chars without terminating \0
  return (int)idx;
}

///////////////////////////////////////////////////////////////////////////////

int printf(const char *format, ...) {
  va_list va;
  va_start(va, format);
  char buffer[1];
  const int ret = _vsnprintf(_out_char, buffer, (size_t)-1, format, va);
  va_end(va);
  return ret;
}

int vprintf(const char *format, va_list va) {
  char buffer[1];
  return _vsnprintf(_out_char, buffer, (size_t)-1, format, va);
}

int fprintf(FILE *stream, const char *format, ...) {
  va_list va;
  va_start(va, format);
  const int ret = _vsnprintf(_out_file, (char *)stream, (size_t)-1, format, va);
  va_end(va);
  return ret;
}
int vfprintf(FILE *stream, const char *format, va_list va) {
  return _vsnprintf(_out_file, (char *)stream, (size_t)-1, format, va);
}

int sprintf(char *buffer, const char *format, ...) {
  va_list va;
  va_start(va, format);
  const int ret = _vsnprintf(_out_buffer, buffer, (size_t)-1, format, va);
  va_end(va);
  return ret;
}

int snprintf(char *buffer, size_t count, const char *format, ...) {
  va_list va;
  va_start(va, format);
  const int ret = _vsnprintf(_out_buffer, buffer, count, format, va);
  va_end(va);
  return ret;
}

int vsnprintf(char *buffer, size_t count, const char *format, va_list va) {
  return _vsnprintf(_out_buffer, buffer, count, format, va);
}