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pikapython/package/pika_libc/pika_vsnprintf.c
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/*
* Copyright (c) 2021, Meco Jianting Man <jiantingman@foxmail.com>
*
* SPDX-License-Identifier: Apache-2.0
*
* Change Logs:
* Date Author Notes
* 2021-11-27 Meco Man porting for rt_vsnprintf as the fully functional
* version
*/
/**
* @author (c) Eyal Rozenberg <eyalroz1@gmx.com>
* 2021, 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.
*
* @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.
*/
#include <stdarg.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
#include "PikaObj.h"
#include "pika_adapter_rtt.h"
#if !PIKASCRIPT_VERSION_REQUIRE_MINIMUN(1, 12, 0)
#error "pika_vsnprintf.c requires at least PikaScript 1.12.0"
#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
// 'ftoa' conversion buffer size, this must be big enough to hold one converted
// float number including padded zeros (dynamically created on stack)
#ifndef PRINTF_FTOA_BUFFER_SIZE
#define PRINTF_FTOA_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 notatin floating point conversion specifiers (%e,
// %g, %E, %G)
#ifndef PRINTF_SUPPORT_EXPONENTIAL_SPECIFIERS
#define PRINTF_SUPPORT_EXPONENTIAL_SPECIFIERS 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
#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
#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_LONG (1U << 8U)
#define FLAGS_LONG_LONG (1U << 9U)
#define FLAGS_PRECISION (1U << 10U)
#define FLAGS_ADAPT_EXP (1U << 11U)
#define FLAGS_POINTER (1U << 12U)
// Note: Similar, but not identical, effect as FLAGS_HASH
#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_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
#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
#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 double_with_bit_access get_bit_access(double x) {
double_with_bit_access dwba;
dwba.F = x;
return dwba;
}
static inline int get_sign(double x) {
// The sign is stored in the highest bit
return 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)))
// output function type
typedef void (*out_fct_type)(char character,
void* buffer,
size_t idx,
size_t maxlen);
// wrapper (used as buffer) for output function type
typedef struct {
void (*fct)(char character, void* arg);
void* arg;
} out_function_wrapper_type;
// 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_discard(char character,
void* buffer,
size_t idx,
size_t maxlen) {
(void)character;
(void)buffer;
(void)idx;
(void)maxlen;
}
// 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;
}
// 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 size_t print_integer_finalization(out_fct_type out,
char* buffer,
size_t idx,
size_t maxlen,
char* buf,
size_t len,
bool negative,
numeric_base_t base,
unsigned int precision,
unsigned int width,
unsigned int flags) {
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--;
}
if (len && (base == BASE_HEX)) {
if (unpadded_len < len) {
len--;
}
}
}
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++] = ' ';
}
}
return out_rev_(out, buffer, idx, maxlen, buf, len, width, flags);
}
// An internal itoa-like function
static size_t print_integer(out_fct_type out,
char* buffer,
size_t idx,
size_t maxlen,
printf_unsigned_value_t value,
bool negative,
numeric_base_t base,
unsigned int precision,
unsigned int width,
unsigned int flags) {
char buf[PRINTF_INTEGER_BUFFER_SIZE];
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));
}
return print_integer_finalization(out, buffer, idx, maxlen, buf, len,
negative, base, precision, width, flags);
}
#if (PRINTF_SUPPORT_DECIMAL_SPECIFIERS || PRINTF_SUPPORT_EXPONENTIAL_SPECIFIERS)
struct double_components {
int_fast64_t integral;
int_fast64_t fractional;
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 double_components get_components(double number,
unsigned int precision) {
struct double_components number_;
number_.is_negative = get_sign(number);
double abs_number = (number_.is_negative) ? -number : number;
number_.integral = (int_fast64_t)abs_number;
double remainder =
(abs_number - 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) {
if ((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_;
}
struct scaling_factor {
double raw_factor;
bool multiply; // if true, need to multiply by raw_factor; otherwise need
// to divide by it
};
double apply_scaling(double num, struct scaling_factor normalization) {
return normalization.multiply ? num * normalization.raw_factor
: num / normalization.raw_factor;
}
double unapply_scaling(double normalized, struct scaling_factor normalization) {
return normalization.multiply ? normalized / normalization.raw_factor
: normalized * normalization.raw_factor;
}
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;
}
#if PRINTF_SUPPORT_EXPONENTIAL_SPECIFIERS
static struct double_components get_normalized_components(
bool negative,
unsigned int precision,
double non_normalized,
struct scaling_factor normalization) {
struct double_components components;
components.is_negative = negative;
components.integral =
(int_fast64_t)apply_scaling(non_normalized, normalization);
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;
if (precision == 0U) {
components.fractional = 0;
components.integral += (scaled_remainder >= rounding_threshold);
if (scaled_remainder == rounding_threshold) {
// banker's rounding: Round towards the even number (making the mean
// error 0)
components.integral &= ~((int_fast64_t)0x1);
}
} else {
components.fractional = (int_fast64_t)scaled_remainder;
scaled_remainder -= components.fractional;
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).
if ((double)components.fractional >= prec_power_of_10) {
components.fractional = 0;
++components.integral;
}
}
return components;
}
#endif
static size_t print_broken_up_decimal(struct double_components number_,
out_fct_type out,
char* buffer,
size_t idx,
size_t maxlen,
unsigned int precision,
unsigned int width,
unsigned int flags,
char* buf,
size_t len) {
if (precision != 0U) {
// do fractional part, as an unsigned number
unsigned int count = precision;
if (flags & FLAGS_ADAPT_EXP && !(flags & FLAGS_HASH)) {
// %g/%G mandates we skip the trailing 0 digits...
if (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_FTOA_BUFFER_SIZE) {
--count;
buf[len++] = (char)('0' + number_.fractional % 10U);
if (!(number_.fractional /= 10U)) {
break;
}
}
// add extra 0s
while ((len < PRINTF_FTOA_BUFFER_SIZE) && (count-- > 0U)) {
buf[len++] = '0';
}
if (len < PRINTF_FTOA_BUFFER_SIZE) {
buf[len++] = '.';
}
}
} else {
if (flags & FLAGS_HASH) {
if (len < PRINTF_FTOA_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_FTOA_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_FTOA_BUFFER_SIZE)) {
buf[len++] = '0';
}
}
if (len < PRINTF_FTOA_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++] = ' ';
}
}
return out_rev_(out, buffer, idx, maxlen, buf, len, width, flags);
}
// internal ftoa for fixed decimal floating point
static size_t print_decimal_number(out_fct_type out,
char* buffer,
size_t idx,
size_t maxlen,
double number,
unsigned int precision,
unsigned int width,
unsigned int flags,
char* buf,
size_t len) {
struct double_components value_ = get_components(number, precision);
return print_broken_up_decimal(value_, out, buffer, idx, maxlen, precision,
width, flags, buf, len);
}
#if PRINTF_SUPPORT_EXPONENTIAL_SPECIFIERS
// internal ftoa variant for exponential floating-point type, contributed by
// Martijn Jasperse <m.jasperse@gmail.com>
static size_t print_exponential_number(out_fct_type out,
char* buffer,
size_t idx,
size_t maxlen,
double number,
unsigned int precision,
unsigned int width,
unsigned int flags,
char* buf,
size_t len) {
const bool negative = get_sign(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 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.
exp10 = 0; // ... and no need to set a normalization factor or check
// the powers table
} else {
double_with_bit_access conv = get_bit_access(abs_number);
{
// based on the algorithm by David Gay
// (https://www.ampl.com/netlib/fp/dtoa.c)
int exp2 = get_exp2(conv);
// drop the exponent, so conv.F comes into the range [1,2)
conv.U =
(conv.U &
(((double_uint_t)(1) << DOUBLE_STORED_MANTISSA_BITS) - 1U)) |
((double_uint_t)DOUBLE_BASE_EXPONENT
<< DOUBLE_STORED_MANTISSA_BITS);
// now approximate log10 from the log2 integer part and an expansion
// of ln around 1.5
exp10 = (int)(0.1760912590558 + exp2 * 0.301029995663981 +
(conv.F - 1.5) * 0.289529654602168);
// now we want to compute 10^exp10 but we want to be sure it won't
// overflow
exp2 = (int)(exp10 * 3.321928094887362 + 0.5);
const double z =
exp10 * 2.302585092994046 - exp2 * 0.6931471805599453;
const double z2 = z * z;
conv.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
conv.F *= 1 + 2 * z / (2 - z + (z2 / (6 + (z2 / (10 + z2 / 14)))));
// correct for rounding errors
if (abs_number < conv.F) {
exp10--;
conv.F /= 10;
}
}
abs_exp10_covered_by_powers_table =
PRINTF_ABS(exp10) < PRINTF_MAX_PRECOMPUTED_POWER_OF_10;
normalization.raw_factor = abs_exp10_covered_by_powers_table
? powers_of_10[PRINTF_ABS(exp10)]
: conv.F;
}
// 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 =
(exp10 >= -4 && 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 - 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 = (exp10 < 0 && abs_exp10_covered_by_powers_table);
bool should_skip_normalization =
(fall_back_to_decimal_only_mode || 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);
// 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) && exp10 >= -1 &&
decimal_part_components.integral == powers_of_10[exp10 + 1]) {
exp10++; // Not strictly necessary, since 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) {
exp10++;
decimal_part_components.integral = 1;
decimal_part_components.fractional = 0;
}
}
// the exp10 format is "E%+03d" and largest possible exp10 value for a
// 64-bit double is "307" (for 2^1023), so we set aside 4-5 characters
// overall
unsigned int exp10_part_width = fall_back_to_decimal_only_mode ? 0U
: (PRINTF_ABS(exp10) < 100) ? 4U
: 5U;
unsigned int 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 size_t start_idx = idx;
idx = print_broken_up_decimal(decimal_part_components, out, buffer, idx,
maxlen, precision, decimal_part_width, flags,
buf, len);
if (!fall_back_to_decimal_only_mode) {
out((flags & FLAGS_UPPERCASE) ? 'E' : 'e', buffer, idx++, maxlen);
idx = print_integer(out, buffer, idx, maxlen, ABS_FOR_PRINTING(exp10),
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 (idx - start_idx < width)
out(' ', buffer, idx++, maxlen);
}
}
return idx;
}
#endif // PRINTF_SUPPORT_EXPONENTIAL_SPECIFIERS
static size_t print_floating_point(out_fct_type out,
char* buffer,
size_t idx,
size_t maxlen,
double value,
unsigned int precision,
unsigned int width,
unsigned int flags,
bool prefer_exponential) {
char buf[PRINTF_FTOA_BUFFER_SIZE];
size_t len = 0U;
// 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);
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
return print_exponential_number(out, buffer, idx, maxlen, value,
precision, width, flags, buf, len);
#else
return 0U;
#endif
}
// 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_FTOA_BUFFER_SIZE) &&
(precision > PRINTF_MAX_SUPPORTED_PRECISION)) {
buf[len++] =
'0'; // This respects the precision in terms of result length only
precision--;
}
return
#if PRINTF_SUPPORT_EXPONENTIAL_SPECIFIERS
prefer_exponential
? print_exponential_number(out, buffer, idx, maxlen, value,
precision, width, flags, buf, len)
:
#endif
print_decimal_number(out, buffer, idx, maxlen, value, precision,
width, flags, buf, len);
}
#endif // (PRINTF_SUPPORT_DECIMAL_SPECIFIERS ||
// PRINTF_SUPPORT_EXPONENTIAL_SPECIFIERS)
// internal vsnprintf
static int __vsnprintf(out_fct_type out,
char* buffer,
const size_t maxlen,
const char* format,
va_list va) {
unsigned int flags, width, precision, n;
size_t idx = 0U;
if (!buffer) {
// use null output function
out = out_discard;
}
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 precision_ = (int)va_arg(va, int);
precision = precision_ > 0 ? (unsigned int)precision_ : 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;
case 't':
flags |= (sizeof(ptrdiff_t) == sizeof(long) ? FLAGS_LONG
: FLAGS_LONG_LONG);
format++;
break;
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
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; // 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 PRINTF_SUPPORT_LONG_LONG
const long long value = va_arg(va, long long);
idx = print_integer(out, buffer, idx, maxlen,
ABS_FOR_PRINTING(value), value < 0,
base, precision, width, flags);
#endif
} else if (flags & FLAGS_LONG) {
const long value = va_arg(va, long);
idx = print_integer(out, buffer, idx, maxlen,
ABS_FOR_PRINTING(value), value < 0,
base, precision, width, flags);
} else {
const int value =
(flags & FLAGS_CHAR) ? (signed char)va_arg(va, int)
: (flags & FLAGS_SHORT) ? (short int)va_arg(va, int)
: va_arg(va, int);
idx = print_integer(out, buffer, idx, maxlen,
ABS_FOR_PRINTING(value), value < 0,
base, precision, width, flags);
}
} else {
// unsigned
if (flags & FLAGS_LONG_LONG) {
#if PRINTF_SUPPORT_LONG_LONG
idx =
print_integer(out, buffer, idx, maxlen,
(printf_unsigned_value_t)va_arg(
va, unsigned long long),
false, base, precision, width, flags);
#endif
} else if (flags & FLAGS_LONG) {
idx = print_integer(
out, buffer, idx, maxlen,
(printf_unsigned_value_t)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 =
print_integer(out, buffer, idx, maxlen,
(printf_unsigned_value_t)value, false,
base, precision, width, flags);
}
}
format++;
break;
}
#if PRINTF_SUPPORT_DECIMAL_SPECIFIERS
case 'f':
case 'F':
if (*format == 'F')
flags |= FLAGS_UPPERCASE;
idx = print_floating_point(out, buffer, idx, maxlen,
va_arg(va, 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;
idx = print_floating_point(out, buffer, idx, maxlen,
va_arg(va, double), precision, width,
flags, PRINTF_PREFER_EXPONENTIAL);
format++;
break;
#endif // PRINTF_SUPPORT_EXPONENTIAL_SPECIFIERS
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*);
if (p == NULL) {
idx = out_rev_(out, buffer, idx, maxlen, ")llun(", 6, width,
flags);
} else {
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) {
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 +
2; // 2 hex chars per byte + the "0x" prefix
flags |= FLAGS_ZEROPAD | FLAGS_POINTER;
uintptr_t value = (uintptr_t)va_arg(va, void*);
idx = (value == (uintptr_t)NULL)
? out_rev_(out, buffer, idx, maxlen, ")lin(", 5,
width, flags)
: print_integer(out, buffer, idx, maxlen,
(printf_unsigned_value_t)value, false,
BASE_HEX, precision, width, flags);
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;
}
/**
* This function will fill a formatted string to buffer.
*
* @param buf is the buffer to save formatted string.
*
* @param size is the size of buffer.
*
* @param fmt is the format parameters.
*
* @param args is a list of variable parameters.
*
* @return The number of characters actually written to buffer.
*/
int pika_platform_vsnprintf(char* buff,
size_t size,
const char* fmt,
va_list args) {
return __vsnprintf(out_buffer, buff, size, fmt, args);
}
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