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/**
* @author (c) Eyal Rozenberg <eyalroz1@gmx.com>
* 2021-2022, Haifa, Palestine/Israel
* @author (c) Marco Paland (info@paland.com)
* 2014-2019, PALANDesign Hannover, Germany
*
* @note Others have made smaller contributions to this file: see the
* contributors page at https://github.com/eyalroz/printf/graphs/contributors
* or ask one of the authors. The original code for exponential specifiers was
* contributed by Martijn Jasperse <m.jasperse@gmail.com>.
*
* @brief Small stand-alone implementation of the printf family of functions
* (`(v)printf`, `(v)s(n)printf` etc., geared towards use on embedded systems with
* a very limited resources.
*
* @note the implementations are thread-safe; re-entrant; use no functions from
* the standard library; and do not dynamically allocate any memory.
*
* @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.
*/
#pragma GCC diagnostic ignored "-Wfloat-equal"
// Define this globally (e.g. gcc -DPRINTF_INCLUDE_CONFIG_H=1 ...) to include the
// printf_config.h header file
#if PRINTF_INCLUDE_CONFIG_H
#include "printf_config.h"
#endif
#include <printf.h>
#ifdef __cplusplus
#include <cstdint>
#include <climits>
#else
#include <types.h>
#include <limits.h>
#endif // __cplusplus
#if PRINTF_ALIAS_STANDARD_FUNCTION_NAMES
#define printf printf
#define sprintf sprintf
#define vsprintf vsprintf
#define snprintf_ snprintf
#define vsnprintf vsnprintf
#define vprintf vprintf
#endif
// 'ntoa' conversion buffer size, this must be big enough to hold one converted
// numeric number including padded zeros (dynamically created on stack)
#ifndef PRINTF_INTEGER_BUFFER_SIZE
#define PRINTF_INTEGER_BUFFER_SIZE 32
#endif
// size of the fixed (on-stack) buffer for printing individual decimal numbers.
// this must be big enough to hold one converted floating-point value including
// padded zeros.
#ifndef PRINTF_DECIMAL_BUFFER_SIZE
#define PRINTF_DECIMAL_BUFFER_SIZE 32
#endif
// Support for the decimal notation floating point conversion specifiers (%f, %F)
#ifndef PRINTF_SUPPORT_DECIMAL_SPECIFIERS
#define PRINTF_SUPPORT_DECIMAL_SPECIFIERS 1
#endif
// Support for the exponential notation floating point conversion specifiers (%e, %g, %E, %G)
#ifndef PRINTF_SUPPORT_EXPONENTIAL_SPECIFIERS
#define PRINTF_SUPPORT_EXPONENTIAL_SPECIFIERS 1
#endif
// Support for the length write-back specifier (%n)
#ifndef PRINTF_SUPPORT_WRITEBACK_SPECIFIER
#define PRINTF_SUPPORT_WRITEBACK_SPECIFIER 1
#endif
// Default precision for the floating point conversion specifiers (the C standard sets this at 6)
#ifndef PRINTF_DEFAULT_FLOAT_PRECISION
#define PRINTF_DEFAULT_FLOAT_PRECISION 6
#endif
// According to the C languages standard, printf() and related functions must be able to print any
// integral number in floating-point notation, regardless of length, when using the %f specifier -
// possibly hundreds of characters, potentially overflowing your buffers. In this implementation,
// all values beyond this threshold are switched to exponential notation.
#ifndef PRINTF_MAX_INTEGRAL_DIGITS_FOR_DECIMAL
#define PRINTF_MAX_INTEGRAL_DIGITS_FOR_DECIMAL 9
#endif
// Support for the long long integral types (with the ll, z and t length modifiers for specifiers
// %d,%i,%o,%x,%X,%u, and with the %p specifier). Note: 'L' (long double) is not supported.
#ifndef PRINTF_SUPPORT_LONG_LONG
#define PRINTF_SUPPORT_LONG_LONG 1
#endif
// The number of terms in a Taylor series expansion of log_10(x) to
// use for approximation - including the power-zero term (i.e. the
// value at the point of expansion).
#ifndef PRINTF_LOG10_TAYLOR_TERMS
#define PRINTF_LOG10_TAYLOR_TERMS 4
#endif
#if PRINTF_LOG10_TAYLOR_TERMS <= 1
#error "At least one non-constant Taylor expansion is necessary for the log10() calculation"
#endif
// Be extra-safe, and don't assume format specifiers are completed correctly
// before the format string end.
#ifndef PRINTF_CHECK_FOR_NUL_IN_FORMAT_SPECIFIER
#define PRINTF_CHECK_FOR_NUL_IN_FORMAT_SPECIFIER 1
#endif
#define PRINTF_PREFER_DECIMAL false
#define PRINTF_PREFER_EXPONENTIAL true
///////////////////////////////////////////////////////////////////////////////
// The following will convert the number-of-digits into an exponential-notation literal
#define PRINTF_CONCATENATE(s1, s2) s1##s2
#define PRINTF_EXPAND_THEN_CONCATENATE(s1, s2) PRINTF_CONCATENATE(s1, s2)
#define PRINTF_FLOAT_NOTATION_THRESHOLD PRINTF_EXPAND_THEN_CONCATENATE(1e, PRINTF_MAX_INTEGRAL_DIGITS_FOR_DECIMAL)
// 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_INT (1U << 8U)
// Only used with PRINTF_SUPPORT_MSVC_STYLE_INTEGER_SPECIFIERS
#define FLAGS_LONG (1U << 9U)
#define FLAGS_LONG_LONG (1U << 10U)
#define FLAGS_PRECISION (1U << 11U)
#define FLAGS_ADAPT_EXP (1U << 12U)
#define FLAGS_POINTER (1U << 13U)
// Note: Similar, but not identical, effect as FLAGS_HASH
#define FLAGS_SIGNED (1U << 14U)
// Only used with PRINTF_SUPPORT_MSVC_STYLE_INTEGER_SPECIFIERS
#ifdef PRINTF_SUPPORT_MSVC_STYLE_INTEGER_SPECIFIERS
#define FLAGS_INT8 FLAGS_CHAR
#if (SHRT_MAX == 32767LL)
#define FLAGS_INT16 FLAGS_SHORT
#elif (INT_MAX == 32767LL)
#define FLAGS_INT16 FLAGS_INT
#elif (LONG_MAX == 32767LL)
#define FLAGS_INT16 FLAGS_LONG
#elif (LLONG_MAX == 32767LL)
#define FLAGS_INT16 FLAGS_LONG_LONG
#else
#error "No basic integer type has a size of 16 bits exactly"
#endif
#if (SHRT_MAX == 2147483647LL)
#define FLAGS_INT32 FLAGS_SHORT
#elif (INT_MAX == 2147483647LL)
#define FLAGS_INT32 FLAGS_INT
#elif (LONG_MAX == 2147483647LL)
#define FLAGS_INT32 FLAGS_LONG
#elif (LLONG_MAX == 2147483647LL)
#define FLAGS_INT32 FLAGS_LONG_LONG
#else
#error "No basic integer type has a size of 32 bits exactly"
#endif
#if (SHRT_MAX == 9223372036854775807LL)
#define FLAGS_INT64 FLAGS_SHORT
#elif (INT_MAX == 9223372036854775807LL)
#define FLAGS_INT64 FLAGS_INT
#elif (LONG_MAX == 9223372036854775807LL)
#define FLAGS_INT64 FLAGS_LONG
#elif (LLONG_MAX == 9223372036854775807LL)
#define FLAGS_INT64 FLAGS_LONG_LONG
#else
#error "No basic integer type has a size of 64 bits exactly"
#endif
#endif // PRINTF_SUPPORT_MSVC_STYLE_INTEGER_SPECIFIERS
typedef unsigned int printf_flags_t;
#define BASE_BINARY 2
#define BASE_OCTAL 8
#define BASE_DECIMAL 10
#define BASE_HEX 16
typedef uint8_t numeric_base_t;
#if PRINTF_SUPPORT_LONG_LONG
typedef unsigned long long printf_unsigned_value_t;
typedef long long printf_signed_value_t;
#else
typedef unsigned long printf_unsigned_value_t;
typedef long printf_signed_value_t;
#endif
// The printf()-family functions return an `int`; it is therefore
// unnecessary/inappropriate to use size_t - often larger than int
// in practice - for non-negative related values, such as widths,
// precisions, offsets into buffers used for printing and the sizes
// of these buffers. instead, we use:
typedef unsigned int printf_size_t;
#define PRINTF_MAX_POSSIBLE_BUFFER_SIZE INT_MAX
// If we were to nitpick, this would actually be INT_MAX + 1,
// since INT_MAX is the maximum return value, which excludes the
// trailing '\0'.
#if (PRINTF_SUPPORT_DECIMAL_SPECIFIERS || PRINTF_SUPPORT_EXPONENTIAL_SPECIFIERS)
#include <float.h>
#if FLT_RADIX != 2
#error "Non-binary-radix floating-point types are unsupported."
#endif
#if DBL_MANT_DIG == 24
#define DOUBLE_SIZE_IN_BITS 32
typedef uint32_t double_uint_t;
#define DOUBLE_EXPONENT_MASK 0xFFU
#define DOUBLE_BASE_EXPONENT 127
#define DOUBLE_MAX_SUBNORMAL_EXPONENT_OF_10 -38
#define DOUBLE_MAX_SUBNORMAL_POWER_OF_10 1e-38
#elif DBL_MANT_DIG == 53
#define DOUBLE_SIZE_IN_BITS 64
typedef uint64_t double_uint_t;
#define DOUBLE_EXPONENT_MASK 0x7FFU
#define DOUBLE_BASE_EXPONENT 1023
#define DOUBLE_MAX_SUBNORMAL_EXPONENT_OF_10 -308
#define DOUBLE_MAX_SUBNORMAL_POWER_OF_10 1e-308
#else
#error "Unsupported double type configuration"
#endif
#define DOUBLE_STORED_MANTISSA_BITS (DBL_MANT_DIG - 1)
typedef union
{
double_uint_t U;
double F;
} double_with_bit_access;
// This is unnecessary in C99, since compound initializers can be used,
// but:
// 1. Some compilers are finicky about this;
// 2. Some people may want to convert this to C89;
// 3. If you try to use it as C++, only C++20 supports compound literals
static inline NIF double_with_bit_access get_bit_access(double x)
{
double_with_bit_access dwba;
dwba.F = x;
return dwba;
}
static inline NIF int get_sign_bit(double x)
{
// The sign is stored in the highest bit
return (int)(get_bit_access(x).U >> (DOUBLE_SIZE_IN_BITS - 1));
}
static inline int get_exp2(double_with_bit_access x)
{
// The exponent in an IEEE-754 floating-point number occupies a contiguous
// sequence of bits (e.g. 52..62 for 64-bit doubles), but with a non-trivial representation: An
// unsigned offset from some negative value (with the extremal offset values reserved for
// special use).
return (int)((x.U >> DOUBLE_STORED_MANTISSA_BITS) & DOUBLE_EXPONENT_MASK) - DOUBLE_BASE_EXPONENT;
}
#define PRINTF_ABS(_x) ((_x) > 0 ? (_x) : -(_x))
#endif // (PRINTF_SUPPORT_DECIMAL_SPECIFIERS || PRINTF_SUPPORT_EXPONENTIAL_SPECIFIERS)
// Note in particular the behavior here on LONG_MIN or LLONG_MIN; it is valid
// and well-defined, but if you're not careful you can easily trigger undefined
// behavior with -LONG_MIN or -LLONG_MIN
#define ABS_FOR_PRINTING(_x) ((printf_unsigned_value_t)((_x) > 0 ? (_x) : -((printf_signed_value_t)_x)))
// wrapper (used as buffer) for output function type
//
// One of the following must hold:
// 1. max_chars is 0
// 2. buffer is non-null
// 3. function is non-null
//
// ... otherwise bad things will happen.
typedef struct
{
void (*function)(char c, void *extra_arg);
void *extra_function_arg;
char *buffer;
printf_size_t pos;
printf_size_t max_chars;
} output_gadget_t;
// Note: This function currently assumes it is not passed a '\0' c,
// or alternatively, that '\0' can be passed to the function in the output
// gadget. The former assumption holds within the printf library. It also
// assumes that the output gadget has been properly initialized.
static inline NIF void putchar_via_gadget(output_gadget_t *gadget, char c)
{
printf_size_t write_pos = gadget->pos++;
// We're _always_ increasing pos, so as to count how may characters
// _would_ have been written if not for the max_chars limitation
if (write_pos >= gadget->max_chars)
{
return;
}
if (gadget->function != NULL)
{
// No check for c == '\0' .
gadget->function(c, gadget->extra_function_arg);
}
else
{
// it must be the case that gadget->buffer != NULL , due to the constraint
// on output_gadget_t ; and note we're relying on write_pos being non-negative.
gadget->buffer[write_pos] = c;
}
}
// Possibly-write the string-terminating '\0' character
static inline NIF void append_termination_with_gadget(output_gadget_t *gadget)
{
if (gadget->function != NULL || gadget->max_chars == 0)
{
return;
}
if (gadget->buffer == NULL)
{
return;
}
printf_size_t null_char_pos = gadget->pos < gadget->max_chars ? gadget->pos : gadget->max_chars - 1;
gadget->buffer[null_char_pos] = '\0';
}
extern void putchar(char c);
// We can't use putchar_ as is, since our output gadget
// only takes pointers to functions with an extra argument
static inline NIF void putchar_wrapper(char c, void *unused)
{
putchar(c);
UNUSED(unused);
}
static inline NIF output_gadget_t discarding_gadget(void)
{
output_gadget_t gadget;
gadget.function = NULL;
gadget.extra_function_arg = NULL;
gadget.buffer = NULL;
gadget.pos = 0;
gadget.max_chars = 0;
return gadget;
}
static inline NIF output_gadget_t buffer_gadget(char *buffer, size_t buffer_size)
{
printf_size_t usable_buffer_size = (buffer_size > PRINTF_MAX_POSSIBLE_BUFFER_SIZE) ? PRINTF_MAX_POSSIBLE_BUFFER_SIZE : (printf_size_t)buffer_size;
output_gadget_t result = discarding_gadget();
if (buffer != NULL)
{
result.buffer = buffer;
result.max_chars = usable_buffer_size;
}
return result;
}
static inline NIF output_gadget_t function_gadget(void (*function)(char, void *), void *extra_arg)
{
output_gadget_t result = discarding_gadget();
result.function = function;
result.extra_function_arg = extra_arg;
result.max_chars = PRINTF_MAX_POSSIBLE_BUFFER_SIZE;
return result;
}
static inline NIF output_gadget_t extern_putchar_gadget(void)
{
return function_gadget(putchar_wrapper, NULL);
}
// internal secure strlen
// @return The length of the string (excluding the terminating 0) limited by 'maxsize'
// @note strlen uses size_t, but wes only use this function with printf_size_t
// variables - hence the signature.
static inline NIF printf_size_t strnlen_s_(const char *str, printf_size_t maxsize)
{
const char *s;
for (s = str; *s && maxsize--; ++s)
;
return (printf_size_t)(s - str);
}
// internal test if char is a digit (0-9)
// @return true if char is a digit
static inline NIF bool is_digit_(char ch)
{
return (ch >= '0') && (ch <= '9');
}
// internal ASCII string to printf_size_t conversion
static NIF printf_size_t atou_(const char **str)
{
printf_size_t i = 0U;
while (is_digit_(**str))
{
i = i * 10U + (printf_size_t)(*((*str)++) - '0');
}
return i;
}
// output the specified string in reverse, taking care of any zero-padding
static NIF void out_rev_(output_gadget_t *output, const char *buf, printf_size_t len, printf_size_t width, printf_flags_t flags)
{
const printf_size_t start_pos = output->pos;
// pad spaces up to given width
if (!(flags & FLAGS_LEFT) && !(flags & FLAGS_ZEROPAD))
{
for (printf_size_t i = len; i < width; i++)
{
putchar_via_gadget(output, ' ');
}
}
// reverse string
while (len)
{
putchar_via_gadget(output, buf[--len]);
}
// append pad spaces up to given width
if (flags & FLAGS_LEFT)
{
while (output->pos - start_pos < width)
{
putchar_via_gadget(output, ' ');
}
}
}
// Invoked by print_integer after the actual number has been printed, performing necessary
// work on the number's prefix (as the number is initially printed in reverse order)
static NIF void print_integer_finalization(output_gadget_t *output, char *buf, printf_size_t len, bool negative, numeric_base_t base, printf_size_t precision, printf_size_t width, printf_flags_t flags)
{
printf_size_t unpadded_len = len;
// pad with leading zeros
{
if (!(flags & FLAGS_LEFT))
{
if (width && (flags & FLAGS_ZEROPAD) && (negative || (flags & (FLAGS_PLUS | FLAGS_SPACE))))
{
width--;
}
while ((flags & FLAGS_ZEROPAD) && (len < width) && (len < PRINTF_INTEGER_BUFFER_SIZE))
{
buf[len++] = '0';
}
}
while ((len < precision) && (len < PRINTF_INTEGER_BUFFER_SIZE))
{
buf[len++] = '0';
}
if (base == BASE_OCTAL && (len > unpadded_len))
{
// Since we've written some zeros, we've satisfied the alternative format leading space requirement
flags &= ~FLAGS_HASH;
}
}
// handle hash
if (flags & (FLAGS_HASH | FLAGS_POINTER))
{
if (!(flags & FLAGS_PRECISION) && len && ((len == precision) || (len == width)))
{
// Let's take back some padding digits to fit in what will eventually
// be the format-specific prefix
if (unpadded_len < len)
{
len--; // This should suffice for BASE_OCTAL
}
if (len && (base == BASE_HEX || base == BASE_BINARY) && (unpadded_len < len))
{
len--; // ... and an extra one for 0x or 0b
}
}
if ((base == BASE_HEX) && !(flags & FLAGS_UPPERCASE) && (len < PRINTF_INTEGER_BUFFER_SIZE))
{
buf[len++] = 'x';
}
else if ((base == BASE_HEX) && (flags & FLAGS_UPPERCASE) && (len < PRINTF_INTEGER_BUFFER_SIZE))
{
buf[len++] = 'X';
}
else if ((base == BASE_BINARY) && (len < PRINTF_INTEGER_BUFFER_SIZE))
{
buf[len++] = 'b';
}
if (len < PRINTF_INTEGER_BUFFER_SIZE)
{
buf[len++] = '0';
}
}
if (len < PRINTF_INTEGER_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_(output, buf, len, width, flags);
}
// An internal itoa-like function
static NIF void print_integer(output_gadget_t *output, printf_unsigned_value_t value, bool negative, numeric_base_t base, printf_size_t precision, printf_size_t width, printf_flags_t flags)
{
char buf[PRINTF_INTEGER_BUFFER_SIZE];
printf_size_t len = 0U;
if (!value)
{
if (!(flags & FLAGS_PRECISION))
{
buf[len++] = '0';
flags &= ~FLAGS_HASH;
// We drop this flag this since either the alternative and regular modes of the specifier
// don't differ on 0 values, or (in the case of octal) we've already provided the special
// handling for this mode.
}
else if (base == BASE_HEX)
{
flags &= ~FLAGS_HASH;
// We drop this flag this since either the alternative and regular modes of the specifier
// don't differ on 0 values
}
}
else
{
do
{
const char digit = (char)(value % base);
buf[len++] = (char)(digit < 10 ? '0' + digit : (flags & FLAGS_UPPERCASE ? 'A' : 'a') + digit - 10);
value /= base;
} while (value && (len < PRINTF_INTEGER_BUFFER_SIZE));
}
print_integer_finalization(output, buf, len, negative, base, precision, width, flags);
}
#if (PRINTF_SUPPORT_DECIMAL_SPECIFIERS || PRINTF_SUPPORT_EXPONENTIAL_SPECIFIERS)
// Stores a fixed-precision representation of a double relative
// to a fixed precision (which cannot be determined by examining this structure)
struct double_components
{
int_fast64_t integral;
int_fast64_t fractional;
// ... truncation of the actual fractional part of the double value, scaled
// by the precision value
bool is_negative;
};
#define NUM_DECIMAL_DIGITS_IN_INT64_T 18
#define PRINTF_MAX_PRECOMPUTED_POWER_OF_10 NUM_DECIMAL_DIGITS_IN_INT64_T
static const double powers_of_10[NUM_DECIMAL_DIGITS_IN_INT64_T] = {
1e00, 1e01, 1e02, 1e03, 1e04, 1e05, 1e06, 1e07, 1e08,
1e09, 1e10, 1e11, 1e12, 1e13, 1e14, 1e15, 1e16, 1e17};
#define PRINTF_MAX_SUPPORTED_PRECISION NUM_DECIMAL_DIGITS_IN_INT64_T - 1
// Break up a double number - which is known to be a finite non-negative number -
// into its base-10 parts: integral - before the decimal point, and fractional - after it.
// Taken the precision into account, but does not change it even internally.
static struct NIF double_components get_components(double number, printf_size_t precision)
{
struct double_components number_;
number_.is_negative = get_sign_bit(number);
double abs_number = (number_.is_negative) ? -number : number;
number_.integral = (int_fast64_t)abs_number;
double remainder = (abs_number - (double)number_.integral) * powers_of_10[precision];
number_.fractional = (int_fast64_t)remainder;
remainder -= (double)number_.fractional;
if (remainder > 0.5)
{
++number_.fractional;
// handle rollover, e.g. case 0.99 with precision 1 is 1.0
if ((double)number_.fractional >= powers_of_10[precision])
{
number_.fractional = 0;
++number_.integral;
}
}
else if ((remainder == 0.5) && ((number_.fractional == 0U) || (number_.fractional & 1U)))
{
// if halfway, round up if odd OR if last digit is 0
++number_.fractional;
}
if (precision == 0U)
{
remainder = abs_number - (double)number_.integral;
if ((!(remainder < 0.5) || (remainder > 0.5)) && (number_.integral & 1))
{
// exactly 0.5 and ODD, then round up
// 1.5 -> 2, but 2.5 -> 2
++number_.integral;
}
}
return number_;
}
#if PRINTF_SUPPORT_EXPONENTIAL_SPECIFIERS
struct scaling_factor
{
double raw_factor;
bool multiply; // if true, need to multiply by raw_factor; otherwise need to divide by it
};
static double apply_scaling(double num, struct scaling_factor normalization)
{
return normalization.multiply ? num * normalization.raw_factor : num / normalization.raw_factor;
}
static double unapply_scaling(double normalized, struct scaling_factor normalization)
{
#ifdef __GNUC__
// accounting for a static analysis bug in GCC 6.x and earlier
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wmaybe-uninitialized"
#endif
return normalization.multiply ? normalized / normalization.raw_factor : normalized * normalization.raw_factor;
#ifdef __GNUC__
#pragma GCC diagnostic pop
#endif
}
static struct scaling_factor update_normalization(struct scaling_factor sf, double extra_multiplicative_factor)
{
struct scaling_factor result;
if (sf.multiply)
{
result.multiply = true;
result.raw_factor = sf.raw_factor * extra_multiplicative_factor;
}
else
{
int factor_exp2 = get_exp2(get_bit_access(sf.raw_factor));
int extra_factor_exp2 = get_exp2(get_bit_access(extra_multiplicative_factor));
// Divide the larger-exponent raw raw_factor by the smaller
if (PRINTF_ABS(factor_exp2) > PRINTF_ABS(extra_factor_exp2))
{
result.multiply = false;
result.raw_factor = sf.raw_factor / extra_multiplicative_factor;
}
else
{
result.multiply = true;
result.raw_factor = extra_multiplicative_factor / sf.raw_factor;
}
}
return result;
}
static struct double_components get_normalized_components(bool negative, printf_size_t precision, double non_normalized, struct scaling_factor normalization, int floored_exp10)
{
struct double_components components;
components.is_negative = negative;
double scaled = apply_scaling(non_normalized, normalization);
bool close_to_representation_extremum = ((-floored_exp10 + (int)precision) >= DBL_MAX_10_EXP - 1);
if (close_to_representation_extremum)
{
// We can't have a normalization factor which also accounts for the precision, i.e. moves
// some decimal digits into the mantissa, since it's unrepresentable, or nearly unrepresentable.
// So, we'll give up early on getting extra precision...
return get_components(negative ? -scaled : scaled, precision);
}
components.integral = (int_fast64_t)scaled;
double remainder = non_normalized - unapply_scaling((double)components.integral, normalization);
double prec_power_of_10 = powers_of_10[precision];
struct scaling_factor account_for_precision = update_normalization(normalization, prec_power_of_10);
double scaled_remainder = apply_scaling(remainder, account_for_precision);
double rounding_threshold = 0.5;
components.fractional = (int_fast64_t)scaled_remainder; // when precision == 0, the assigned value should be 0
scaled_remainder -= (double)components.fractional; // when precision == 0, this will not change scaled_remainder
components.fractional += (scaled_remainder >= rounding_threshold);
if (scaled_remainder == rounding_threshold)
{
// banker's rounding: Round towards the even number (making the mean error 0)
components.fractional &= ~((int_fast64_t)0x1);
}
// handle rollover, e.g. the case of 0.99 with precision 1 becoming (0,100),
// and must then be corrected into (1, 0).
// Note: for precision = 0, this will "translate" the rounding effect from
// the fractional part to the integral part where it should actually be
// felt (as prec_power_of_10 is 1)
if ((double)components.fractional >= prec_power_of_10)
{
components.fractional = 0;
++components.integral;
}
return components;
}
#endif // PRINTF_SUPPORT_EXPONENTIAL_SPECIFIERS
static NIF void print_broken_up_decimal(
struct double_components number_, output_gadget_t *output, printf_size_t precision,
printf_size_t width, printf_flags_t flags, char *buf, printf_size_t len)
{
if (precision != 0U)
{
// do fractional part, as an unsigned number
printf_size_t count = precision;
// %g/%G mandates we skip the trailing 0 digits...
if ((flags & FLAGS_ADAPT_EXP) && !(flags & FLAGS_HASH) && (number_.fractional > 0))
{
while (true)
{
int_fast64_t digit = number_.fractional % 10U;
if (digit != 0)
{
break;
}
--count;
number_.fractional /= 10U;
}
// ... and even the decimal point if there are no
// non-zero fractional part digits (see below)
}
if (number_.fractional > 0 || !(flags & FLAGS_ADAPT_EXP) || (flags & FLAGS_HASH))
{
while (len < PRINTF_DECIMAL_BUFFER_SIZE)
{
--count;
buf[len++] = (char)('0' + number_.fractional % 10U);
if (!(number_.fractional /= 10U))
{
break;
}
}
// add extra 0s
while ((len < PRINTF_DECIMAL_BUFFER_SIZE) && (count > 0U))
{
buf[len++] = '0';
--count;
}
if (len < PRINTF_DECIMAL_BUFFER_SIZE)
{
buf[len++] = '.';
}
}
}
else
{
if ((flags & FLAGS_HASH) && (len < PRINTF_DECIMAL_BUFFER_SIZE))
{
buf[len++] = '.';
}
}
// Write the integer part of the number (it comes after the fractional
// since the character order is reversed)
while (len < PRINTF_DECIMAL_BUFFER_SIZE)
{
buf[len++] = (char)('0' + (number_.integral % 10));
if (!(number_.integral /= 10))
{
break;
}
}
// pad leading zeros
if (!(flags & FLAGS_LEFT) && (flags & FLAGS_ZEROPAD))
{
if (width && (number_.is_negative || (flags & (FLAGS_PLUS | FLAGS_SPACE))))
{
width--;
}
while ((len < width) && (len < PRINTF_DECIMAL_BUFFER_SIZE))
{
buf[len++] = '0';
}
}
if (len < PRINTF_DECIMAL_BUFFER_SIZE)
{
if (number_.is_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_(output, buf, len, width, flags);
}
// internal ftoa for fixed decimal floating point
static NIF void print_decimal_number(output_gadget_t *output, double number, printf_size_t precision, printf_size_t width, printf_flags_t flags, char *buf, printf_size_t len)
{
struct double_components value_ = get_components(number, precision);
print_broken_up_decimal(value_, output, precision, width, flags, buf, len);
}
#if PRINTF_SUPPORT_EXPONENTIAL_SPECIFIERS
// A floor function - but one which only works for numbers whose
// floor value is representable by an int.
static int bastardized_floor(double x)
{
if (x >= 0)
{
return (int)x;
}
int n = (int)x;
return (((double)n) == x) ? n : n - 1;
}
// Computes the base-10 logarithm of the input number - which must be an actual
// positive number (not infinity or NaN, nor a sub-normal)
static double log10_of_positive(double positive_number)
{
// The implementation follows David Gay (https://www.ampl.com/netlib/fp/dtoa.c).
//
// Since log_10 ( M * 2^x ) = log_10(M) + x , we can separate the components of
// our input number, and need only solve log_10(M) for M between 1 and 2 (as
// the base-2 mantissa is always 1-point-something). In that limited range, a
// Taylor series expansion of log10(x) should serve us well enough; and we'll
// take the mid-point, 1.5, as the point of expansion.
double_with_bit_access dwba = get_bit_access(positive_number);
// based on the algorithm by David Gay (https://www.ampl.com/netlib/fp/dtoa.c)
int exp2 = get_exp2(dwba);
// drop the exponent, so dwba.F comes into the range [1,2)
dwba.U = (dwba.U & (((double_uint_t)(1) << DOUBLE_STORED_MANTISSA_BITS) - 1U)) |
((double_uint_t)DOUBLE_BASE_EXPONENT << DOUBLE_STORED_MANTISSA_BITS);
double z = (dwba.F - 1.5);
return (
// Taylor expansion around 1.5:
0.1760912590556812420 // Expansion term 0: ln(1.5) / ln(10)
+ z * 0.2895296546021678851 // Expansion term 1: (M - 1.5) * 2/3 / ln(10)
#if PRINTF_LOG10_TAYLOR_TERMS > 2
- z * z * 0.0965098848673892950 // Expansion term 2: (M - 1.5)^2 * 2/9 / ln(10)
#if PRINTF_LOG10_TAYLOR_TERMS > 3
+ z * z * z * 0.0428932821632841311 // Expansion term 2: (M - 1.5)^3 * 8/81 / ln(10)
#endif
#endif
// exact log_2 of the exponent x, with logarithm base change
+ exp2 * 0.30102999566398119521 // = exp2 * log_10(2) = exp2 * ln(2)/ln(10)
);
}
static double pow10_of_int(int floored_exp10)
{
// A crude hack for avoiding undesired behavior with barely-normal or slightly-subnormal values.
if (floored_exp10 == DOUBLE_MAX_SUBNORMAL_EXPONENT_OF_10)
{
return DOUBLE_MAX_SUBNORMAL_POWER_OF_10;
}
// Compute 10^(floored_exp10) but (try to) make sure that doesn't overflow
double_with_bit_access dwba;
int exp2 = bastardized_floor(floored_exp10 * 3.321928094887362 + 0.5);
const double z = floored_exp10 * 2.302585092994046 - exp2 * 0.6931471805599453;
const double z2 = z * z;
dwba.U = ((double_uint_t)(exp2) + DOUBLE_BASE_EXPONENT) << DOUBLE_STORED_MANTISSA_BITS;
// compute exp(z) using continued fractions,
// see https://en.wikipedia.org/wiki/Exponential_function#Continued_fractions_for_ex
dwba.F *= 1 + 2 * z / (2 - z + (z2 / (6 + (z2 / (10 + z2 / 14)))));
return dwba.F;
}
static NIF void print_exponential_number(output_gadget_t *output, double number, printf_size_t precision, printf_size_t width, printf_flags_t flags, char *buf, printf_size_t len)
{
const bool negative = get_sign_bit(number);
// This number will decrease gradually (by factors of 10) as we "extract" the exponent out of it
double abs_number = negative ? -number : number;
int floored_exp10;
bool abs_exp10_covered_by_powers_table;
struct scaling_factor normalization;
// Determine the decimal exponent
if (abs_number == 0.0)
{
// TODO: This is a special-case for 0.0 (and -0.0); but proper handling is required for denormals more generally.
floored_exp10 = 0; // ... and no need to set a normalization factor or check the powers table
}
else
{
double exp10 = log10_of_positive(abs_number);
floored_exp10 = bastardized_floor(exp10);
double p10 = pow10_of_int(floored_exp10);
// correct for rounding errors
if (abs_number < p10)
{
floored_exp10--;
p10 /= 10;
}
abs_exp10_covered_by_powers_table = PRINTF_ABS(floored_exp10) < PRINTF_MAX_PRECOMPUTED_POWER_OF_10;
normalization.raw_factor = abs_exp10_covered_by_powers_table ? powers_of_10[PRINTF_ABS(floored_exp10)] : p10;
}
// We now begin accounting for the widths of the two parts of our printed field:
// the decimal part after decimal exponent extraction, and the base-10 exponent part.
// For both of these, the value of 0 has a special meaning, but not the same one:
// a 0 exponent-part width means "don't print the exponent"; a 0 decimal-part width
// means "use as many characters as necessary".
bool fall_back_to_decimal_only_mode = false;
if (flags & FLAGS_ADAPT_EXP)
{
int required_significant_digits = (precision == 0) ? 1 : (int)precision;
// Should we want to fall-back to "%f" mode, and only print the decimal part?
fall_back_to_decimal_only_mode = (floored_exp10 >= -4 && floored_exp10 < required_significant_digits);
// Now, let's adjust the precision
// This also decided how we adjust the precision value - as in "%g" mode,
// "precision" is the number of _significant digits_, and this is when we "translate"
// the precision value to an actual number of decimal digits.
int precision_ = fall_back_to_decimal_only_mode ? (int)precision - 1 - floored_exp10 : (int)precision - 1; // the presence of the exponent ensures only one significant digit comes before the decimal point
precision = (precision_ > 0 ? (unsigned)precision_ : 0U);
flags |= FLAGS_PRECISION; // make sure print_broken_up_decimal respects our choice above
}
normalization.multiply = (floored_exp10 < 0 && abs_exp10_covered_by_powers_table);
bool should_skip_normalization = (fall_back_to_decimal_only_mode || floored_exp10 == 0);
struct double_components decimal_part_components =
should_skip_normalization ? get_components(negative ? -abs_number : abs_number, precision) : get_normalized_components(negative, precision, abs_number, normalization, floored_exp10);
// Account for roll-over, e.g. rounding from 9.99 to 100.0 - which effects
// the exponent and may require additional tweaking of the parts
if (fall_back_to_decimal_only_mode)
{
if ((flags & FLAGS_ADAPT_EXP) && floored_exp10 >= -1 && decimal_part_components.integral == powers_of_10[floored_exp10 + 1])
{
floored_exp10++; // Not strictly necessary, since floored_exp10 is no longer really used
precision--;
// ... and it should already be the case that decimal_part_components.fractional == 0
}
// TODO: What about rollover strictly within the fractional part?
}
else
{
if (decimal_part_components.integral >= 10)
{
floored_exp10++;
decimal_part_components.integral = 1;
decimal_part_components.fractional = 0;
}
}
// the floored_exp10 format is "E%+03d" and largest possible floored_exp10 value for a 64-bit double
// is "307" (for 2^1023), so we set aside 4-5 characters overall
printf_size_t exp10_part_width = fall_back_to_decimal_only_mode ? 0U : (PRINTF_ABS(floored_exp10) < 100) ? 4U
: 5U;
printf_size_t decimal_part_width =
((flags & FLAGS_LEFT) && exp10_part_width) ?
// We're padding on the right, so the width constraint is the exponent part's
// problem, not the decimal part's, so we'll use as many characters as we need:
0U
:
// We're padding on the left; so the width constraint is the decimal part's
// problem. Well, can both the decimal part and the exponent part fit within our overall width?
((width > exp10_part_width) ?
// Yes, so we limit our decimal part's width.
// (Note this is trivially valid even if we've fallen back to "%f" mode)
width - exp10_part_width
:
// No; we just give up on any restriction on the decimal part and use as many
// characters as we need
0U);
const printf_size_t printed_exponential_start_pos = output->pos;
print_broken_up_decimal(decimal_part_components, output, precision, decimal_part_width, flags, buf, len);
if (!fall_back_to_decimal_only_mode)
{
putchar_via_gadget(output, (flags & FLAGS_UPPERCASE) ? 'E' : 'e');
print_integer(output,
ABS_FOR_PRINTING(floored_exp10),
floored_exp10 < 0, 10, 0, exp10_part_width - 1,
FLAGS_ZEROPAD | FLAGS_PLUS);
if (flags & FLAGS_LEFT)
{
// We need to right-pad with spaces to meet the width requirement
while (output->pos - printed_exponential_start_pos < width)
{
putchar_via_gadget(output, ' ');
}
}
}
}
#endif // PRINTF_SUPPORT_EXPONENTIAL_SPECIFIERS
static NIF void print_floating_point(output_gadget_t *output, double value, printf_size_t precision, printf_size_t width, printf_flags_t flags, bool prefer_exponential)
{
char buf[PRINTF_DECIMAL_BUFFER_SIZE];
printf_size_t len = 0U;
// test for special values
if (value != value)
{
out_rev_(output, "nan", 3, width, flags);
return;
}
if (value < -DBL_MAX)
{
out_rev_(output, "fni-", 4, width, flags);
return;
}
if (value > DBL_MAX)
{
out_rev_(output, (flags & FLAGS_PLUS) ? "fni+" : "fni", (flags & FLAGS_PLUS) ? 4U : 3U, width, flags);
return;
}
if (!prefer_exponential &&
((value > PRINTF_FLOAT_NOTATION_THRESHOLD) || (value < -PRINTF_FLOAT_NOTATION_THRESHOLD)))
{
// The required behavior of standard printf is to print _every_ integral-part digit -- which could mean
// printing hundreds of characters, overflowing any fixed internal buffer and necessitating a more complicated
// implementation.
#if PRINTF_SUPPORT_EXPONENTIAL_SPECIFIERS
print_exponential_number(output, value, precision, width, flags, buf, len);
#endif
return;
}
// set default precision, if not set explicitly
if (!(flags & FLAGS_PRECISION))
{
precision = PRINTF_DEFAULT_FLOAT_PRECISION;
}
// limit precision so that our integer holding the fractional part does not overflow
while ((len < PRINTF_DECIMAL_BUFFER_SIZE) && (precision > PRINTF_MAX_SUPPORTED_PRECISION))
{
buf[len++] = '0'; // This respects the precision in terms of result length only
precision--;
}
#if PRINTF_SUPPORT_EXPONENTIAL_SPECIFIERS
if (prefer_exponential)
print_exponential_number(output, value, precision, width, flags, buf, len);
else
#endif
print_decimal_number(output, value, precision, width, flags, buf, len);
}
#endif // (PRINTF_SUPPORT_DECIMAL_SPECIFIERS || PRINTF_SUPPORT_EXPONENTIAL_SPECIFIERS)
// Advances the format pointer past the flags, and returns the parsed flags
// due to the characters passed
static NIF printf_flags_t parse_flags(const char **format)
{
printf_flags_t flags = 0U;
do
{
switch (**format)
{
case '0':
flags |= FLAGS_ZEROPAD;
(*format)++;
break;
case '-':
flags |= FLAGS_LEFT;
(*format)++;
break;
case '+':
flags |= FLAGS_PLUS;
(*format)++;
break;
case ' ':
flags |= FLAGS_SPACE;
(*format)++;
break;
case '#':
flags |= FLAGS_HASH;
(*format)++;
break;
default:
return flags;
}
} while (true);
}
static inline NIF void format_string_loop(output_gadget_t *output, const char *format, va_list args)
{
#if PRINTF_CHECK_FOR_NUL_IN_FORMAT_SPECIFIER
#define ADVANCE_IN_FORMAT_STRING(cptr_) \
do \
{ \
(cptr_)++; \
if (!*(cptr_)) \
return; \
} while (0)
#else
#define ADVANCE_IN_FORMAT_STRING(cptr_) (cptr_)++
#endif
while (*format)
{
if (*format != '%')
{
// A regular content character
putchar_via_gadget(output, *format);
format++;
continue;
}
// We're parsing a format specifier: %[flags][width][.precision][length]
ADVANCE_IN_FORMAT_STRING(format);
printf_flags_t flags = parse_flags(&format);
// evaluate width field
printf_size_t width = 0U;
if (is_digit_(*format))
{
width = (printf_size_t)atou_(&format);
}
else if (*format == '*')
{
const int w = va_arg(args, int);
if (w < 0)
{
flags |= FLAGS_LEFT; // reverse padding
width = (printf_size_t)-w;
}
else
{
width = (printf_size_t)w;
}
ADVANCE_IN_FORMAT_STRING(format);
}
// evaluate precision field
printf_size_t precision = 0U;
if (*format == '.')
{
flags |= FLAGS_PRECISION;
ADVANCE_IN_FORMAT_STRING(format);
if (is_digit_(*format))
{
precision = (printf_size_t)atou_(&format);
}
else if (*format == '*')
{
const int precision_ = va_arg(args, int);
precision = precision_ > 0 ? (printf_size_t)precision_ : 0U;
ADVANCE_IN_FORMAT_STRING(format);
}
}
// evaluate length field
switch (*format)
{
#ifdef PRINTF_SUPPORT_MSVC_STYLE_INTEGER_SPECIFIERS
case 'I':
{
ADVANCE_IN_FORMAT_STRING(format);
// Greedily parse for size in bits: 8, 16, 32 or 64
switch (*format)
{
case '8':
flags |= FLAGS_INT8;
ADVANCE_IN_FORMAT_STRING(format);
break;
case '1':
ADVANCE_IN_FORMAT_STRING(format);
if (*format == '6')
{
format++;
flags |= FLAGS_INT16;
}
break;
case '3':
ADVANCE_IN_FORMAT_STRING(format);
if (*format == '2')
{
ADVANCE_IN_FORMAT_STRING(format);
flags |= FLAGS_INT32;
}
break;
case '6':
ADVANCE_IN_FORMAT_STRING(format);
if (*format == '4')
{
ADVANCE_IN_FORMAT_STRING(format);
flags |= FLAGS_INT64;
}
break;
default:
break;
}
break;
}
#endif
case 'l':
flags |= FLAGS_LONG;
ADVANCE_IN_FORMAT_STRING(format);
if (*format == 'l')
{
flags |= FLAGS_LONG_LONG;
ADVANCE_IN_FORMAT_STRING(format);
}
break;
case 'h':
flags |= FLAGS_SHORT;
ADVANCE_IN_FORMAT_STRING(format);
if (*format == 'h')
{
flags |= FLAGS_CHAR;
ADVANCE_IN_FORMAT_STRING(format);
}
break;
case 't':
flags |= (sizeof(ptrdiff_t) == sizeof(long) ? FLAGS_LONG : FLAGS_LONG_LONG);
ADVANCE_IN_FORMAT_STRING(format);
break;
case 'j':
flags |= (sizeof(intmax_t) == sizeof(long) ? FLAGS_LONG : FLAGS_LONG_LONG);
ADVANCE_IN_FORMAT_STRING(format);
break;
case 'z':
flags |= (sizeof(size_t) == sizeof(long) ? FLAGS_LONG : FLAGS_LONG_LONG);
ADVANCE_IN_FORMAT_STRING(format);
break;
default:
break;
}
// evaluate specifier
switch (*format)
{
case 'd':
case 'i':
case 'u':
case 'x':
case 'X':
case 'o':
case 'b':
{
if (*format == 'd' || *format == 'i')
{
flags |= FLAGS_SIGNED;
}
numeric_base_t base;
if (*format == 'x' || *format == 'X')
{
base = BASE_HEX;
}
else if (*format == 'o')
{
base = BASE_OCTAL;
}
else if (*format == 'b')
{
base = BASE_BINARY;
}
else
{
base = BASE_DECIMAL;
flags &= ~FLAGS_HASH; // decimal integers have no alternative presentation
}
if (*format == 'X')
{
flags |= FLAGS_UPPERCASE;
}
format++;
// ignore '0' flag when precision is given
if (flags & FLAGS_PRECISION)
{
flags &= ~FLAGS_ZEROPAD;
}
if (flags & FLAGS_SIGNED)
{
// A signed specifier: d, i or possibly I + bit size if enabled
if (flags & FLAGS_LONG_LONG)
{
#if PRINTF_SUPPORT_LONG_LONG
const long long value = va_arg(args, long long);
print_integer(output, ABS_FOR_PRINTING(value), value < 0, base, precision, width, flags);
#endif
}
else if (flags & FLAGS_LONG)
{
const long value = va_arg(args, long);
print_integer(output, ABS_FOR_PRINTING(value), value < 0, base, precision, width, flags);
}
else
{
// We never try to interpret the argument as something potentially-smaller than int,
// due to integer promotion rules: Even if the user passed a short int, short unsigned
// etc. - these will come in after promotion, as int's (or unsigned for the case of
// short unsigned when it has the same size as int)
const int value =
(flags & FLAGS_CHAR) ? (signed char)va_arg(args, int) : (flags & FLAGS_SHORT) ? (short int)va_arg(args, int)
: va_arg(args, int);
print_integer(output, ABS_FOR_PRINTING(value), value < 0, base, precision, width, flags);
}
}
else
{
// An unsigned specifier: u, x, X, o, b
flags &= ~(FLAGS_PLUS | FLAGS_SPACE);
if (flags & FLAGS_LONG_LONG)
{
#if PRINTF_SUPPORT_LONG_LONG
print_integer(output, (printf_unsigned_value_t)va_arg(args, unsigned long long), false, base, precision, width, flags);
#endif
}
else if (flags & FLAGS_LONG)
{
print_integer(output, (printf_unsigned_value_t)va_arg(args, unsigned long), false, base, precision, width, flags);
}
else
{
const unsigned int value =
(flags & FLAGS_CHAR) ? (unsigned char)va_arg(args, unsigned int) : (flags & FLAGS_SHORT) ? (unsigned short int)va_arg(args, unsigned int)
: va_arg(args, unsigned int);
print_integer(output, (printf_unsigned_value_t)value, false, base, precision, width, flags);
}
}
break;
}
#if PRINTF_SUPPORT_DECIMAL_SPECIFIERS
case 'f':
case 'F':
if (*format == 'F')
flags |= FLAGS_UPPERCASE;
print_floating_point(output, va_arg(args, double), precision, width, flags, PRINTF_PREFER_DECIMAL);
format++;
break;
#endif
#if PRINTF_SUPPORT_EXPONENTIAL_SPECIFIERS
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;
print_floating_point(output, va_arg(args, double), precision, width, flags, PRINTF_PREFER_EXPONENTIAL);
format++;
break;
#endif // PRINTF_SUPPORT_EXPONENTIAL_SPECIFIERS
case 'c':
{
printf_size_t l = 1U;
// pre padding
if (!(flags & FLAGS_LEFT))
{
while (l++ < width)
{
putchar_via_gadget(output, ' ');
}
}
// char output
putchar_via_gadget(output, (char)va_arg(args, int));
// post padding
if (flags & FLAGS_LEFT)
{
while (l++ < width)
{
putchar_via_gadget(output, ' ');
}
}
format++;
break;
}
case 's':
{
const char *p = va_arg(args, char *);
if (p == NULL)
{
out_rev_(output, ")llun(", 6, width, flags);
}
else
{
printf_size_t l = strnlen_s_(p, precision ? precision : PRINTF_MAX_POSSIBLE_BUFFER_SIZE);
// pre padding
if (flags & FLAGS_PRECISION)
{
l = (l < precision ? l : precision);
}
if (!(flags & FLAGS_LEFT))
{
while (l++ < width)
{
putchar_via_gadget(output, ' ');
}
}
// string output
while ((*p != 0) && (!(flags & FLAGS_PRECISION) || precision))
{
putchar_via_gadget(output, *(p++));
--precision;
}
// post padding
if (flags & FLAGS_LEFT)
{
while (l++ < width)
{
putchar_via_gadget(output, ' ');
}
}
}
format++;
break;
}
case 'p':
{
width = sizeof(void *) * 2U + 2; // 2 hex chars per byte + the "0x" prefix
flags |= FLAGS_ZEROPAD | FLAGS_POINTER;
uintptr_t value = (uintptr_t)va_arg(args, void *);
(value == (uintptr_t)NULL) ? out_rev_(output, ")lin(", 5, width, flags) : print_integer(output, (printf_unsigned_value_t)value, false, BASE_HEX, precision, width, flags);
format++;
break;
}
case '%':
putchar_via_gadget(output, '%');
format++;
break;
// Many people prefer to disable support for %n, as it lets the caller
// engineer a write to an arbitrary location, of a value the caller
// effectively controls - which could be a security concern in some cases.
#if PRINTF_SUPPORT_WRITEBACK_SPECIFIER
case 'n':
{
if (flags & FLAGS_CHAR)
*(va_arg(args, char *)) = (char)output->pos;
else if (flags & FLAGS_SHORT)
*(va_arg(args, short *)) = (short)output->pos;
else if (flags & FLAGS_LONG)
*(va_arg(args, long *)) = (long)output->pos;
#if PRINTF_SUPPORT_LONG_LONG
else if (flags & FLAGS_LONG_LONG)
*(va_arg(args, long long *)) = (long long int)output->pos;
#endif // PRINTF_SUPPORT_LONG_LONG
else
*(va_arg(args, int *)) = (int)output->pos;
format++;
break;
}
#endif // PRINTF_SUPPORT_WRITEBACK_SPECIFIER
default:
putchar_via_gadget(output, *format);
format++;
break;
}
}
}
// internal vsnprintf - used for implementing _all library functions
static NIF int vsnprintf_impl(output_gadget_t *output, const char *format, va_list args)
{
// Note: The library only calls vsnprintf_impl() with output->pos being 0. However, it is
// possible to call this function with a non-zero pos value for some "remedial printing".
format_string_loop(output, format, args);
// termination
append_termination_with_gadget(output);
// return written chars without terminating \0
return (int)output->pos;
}
///////////////////////////////////////////////////////////////////////////////
NIF int vprintf(const char *format, va_list arg)
{
output_gadget_t gadget = extern_putchar_gadget();
return vsnprintf_impl(&gadget, format, arg);
}
NIF int vsnprintf(char *s, size_t n, const char *format, va_list arg)
{
output_gadget_t gadget = buffer_gadget(s, n);
return vsnprintf_impl(&gadget, format, arg);
}
NIF int vsprintf(char *s, const char *format, va_list arg)
{
return vsnprintf(s, PRINTF_MAX_POSSIBLE_BUFFER_SIZE, format, arg);
}
NIF int vfctprintf(void (*out)(char c, void *extra_arg), void *extra_arg, const char *format, va_list arg)
{
output_gadget_t gadget = function_gadget(out, extra_arg);
return vsnprintf_impl(&gadget, format, arg);
}
NIF int printf(const char *format, ...)
{
va_list args;
va_start(args, format);
const int ret = vprintf(format, args);
va_end(args);
return ret;
}
NIF int sprintf(char *s, const char *format, ...)
{
va_list args;
va_start(args, format);
const int ret = vsprintf(s, format, args);
va_end(args);
return ret;
}
NIF int snprintf(char *s, size_t n, const char *format, ...)
{
va_list args;
va_start(args, format);
const int ret = vsnprintf(s, n, format, args);
va_end(args);
return ret;
}
NIF int fctprintf(void (*out)(char c, void *extra_arg), void *extra_arg, const char *format, ...)
{
va_list args;
va_start(args, format);
const int ret = vfctprintf(out, extra_arg, format, args);
va_end(args);
return ret;
}
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