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mop3/kernel/libk/printf.c
kamkow1 13fee12f59 Hello world over serial
2025-12-16 23:09:13 +01:00

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/**
* @author (c) Eyal Rozenberg <eyalroz1@gmx.com>
* 2021-2024, 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
* 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.
*/
/* printf doesn't seem to like aggressive optimizations */
#if defined(__clang__)
#pragma clang optimize off
#endif
/*
* 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 <libk/printf.h>
#ifdef __cplusplus
#include <cstdint>
#include <climits>
#else
#include <stdint.h>
#include <limits.h>
#include <stdbool.h>
#endif /* __cplusplus */
#if !(defined(__cplusplus) || (defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199901L))
/* C90 */
#if defined(_MSC_VER)
#define inline __inline
#else
#define inline __inline__
#endif /* defined(_MSC_VER) */
#endif /* !(defined(__cplusplus) || (defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199901L)) */
#if PRINTF_ALIAS_STANDARD_FUNCTION_NAMES_HARD
# define printf_ printf
# define sprintf_ sprintf
# define vsprintf_ vsprintf
# define snprintf_ snprintf
# define vsnprintf_ vsnprintf
# define vprintf_ vprintf
#endif /* PRINTF_ALIAS_STANDARD_FUNCTION_NAMES_HARD */
/*
* '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 /* PRINTF_INTEGER_BUFFER_SIZE */
/*
* 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
/* Default choice of type to use for internal floating-point computations */
#ifndef PRINTF_USE_DOUBLE_INTERNALLY
#define PRINTF_USE_DOUBLE_INTERNALLY 1
#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).
*/
#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 ((floating_point_t) 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)
#define FLAGS_LONG_DOUBLE (1U << 15U)
/* 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 /* PRINTF_SUPPORT_LONG_LONG */
/*
* 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'.
*/
#define SIGN(_negative,_x) ( (_negative) ? -(_x) : (_x))
#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 /* PRINTF_SUPPORT_DECIMAL_SPECIFIERS || PRINTF_SUPPORT_EXPONENTIAL_SPECIFIERS */
/**
* This library supports taking float-point arguments up to and including
* long double's; but - it currently does _not_ support internal
* representation and manipulation of values as long doubles; the options
* are either single-precision `float` or double-precision `double`.
*/
#if PRINTF_USE_DOUBLE_INTERNALLY
typedef double floating_point_t;
#define FP_TYPE_MANT_DIG DBL_MANT_DIG
#else
typedef float floating_point_t;
#define FP_TYPE_MANT_DIG FLT_MANT_DIG
#endif
#define NUM_DECIMAL_DIGITS_IN_INT64_T 18
#if FP_TYPE_MANT_DIG == 24
typedef uint32_t printf_fp_uint_t;
#define FP_TYPE_SIZE_IN_BITS 32
#define FP_TYPE_EXPONENT_MASK 0xFFU
#define FP_TYPE_BASE_EXPONENT 127
#define FP_TYPE_MAX FLT_MAX
#define FP_TYPE_MAX_10_EXP FLT_MAX_10_EXP
#define FP_TYPE_MAX_SUBNORMAL_EXPONENT_OF_10 -38
#define FP_TYPE_MAX_SUBNORMAL_POWER_OF_10 1e-38f
#define PRINTF_MAX_PRECOMPUTED_POWER_OF_10 10
#elif FP_TYPE_MANT_DIG == 53
typedef uint64_t printf_fp_uint_t;
#define FP_TYPE_SIZE_IN_BITS 64
#define FP_TYPE_EXPONENT_MASK 0x7FFU
#define FP_TYPE_BASE_EXPONENT 1023
#define FP_TYPE_MAX DBL_MAX
#define FP_TYPE_MAX_10_EXP DBL_MAX_10_EXP
#define FP_TYPE_MAX_10_EXP DBL_MAX_10_EXP
#define FP_TYPE_MAX_SUBNORMAL_EXPONENT_OF_10 -308
#define FP_TYPE_MAX_SUBNORMAL_POWER_OF_10 1e-308
#define PRINTF_MAX_PRECOMPUTED_POWER_OF_10 NUM_DECIMAL_DIGITS_IN_INT64_T - 1
#else /* FP_TYPE_MANT_DIG is neither 24 nor 53 */
#error "Unsupported floating point type configuration"
#endif /* FP_TYPE_MANT_DIG */
#define FP_TYPE_STORED_MANTISSA_BITS (FP_TYPE_MANT_DIG - 1)
typedef union {
printf_fp_uint_t U;
floating_point_t F;
} floating_point_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 floating_point_with_bit_access get_bit_access(floating_point_t x)
{
floating_point_with_bit_access dwba;
dwba.F = x;
return dwba;
}
static inline int get_sign_bit(floating_point_t x)
{
/* The sign is stored in the highest bit */
return (int) (get_bit_access(x).U >> (FP_TYPE_SIZE_IN_BITS - 1));
}
static inline int get_exp2(floating_point_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 >> FP_TYPE_STORED_MANTISSA_BITS ) & FP_TYPE_EXPONENT_MASK) - FP_TYPE_BASE_EXPONENT;
}
#define PRINTF_ABS(_x) SIGN( (_x) < 0, (_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 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 void append_termination_with_gadget(output_gadget_t* gadget)
{
printf_size_t null_char_pos;
if (gadget->function != NULL || gadget->max_chars == 0) {
return;
}
if (gadget->buffer == NULL) {
return;
}
null_char_pos = gadget->pos < gadget->max_chars ? gadget->pos : gadget->max_chars - 1;
gadget->buffer[null_char_pos] = '\0';
}
/*
* We can't use putchar_ as is, since our output gadget
* only takes pointers to functions with an extra argument
*/
static inline void putchar_wrapper(char c, void* unused)
{
(void) unused;
putchar_(c);
}
static inline 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 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 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 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 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 bool is_digit_(char ch)
{
return (ch >= '0') && (ch <= '9');
}
/* internal ASCII string to printf_size_t conversion */
static 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 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)) {
printf_size_t i;
for (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 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 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 floating-point number relative
* to a fixed precision (which cannot be determined by examining this structure)
*/
struct floating_point_components {
int_fast64_t integral;
int_fast64_t fractional;
/*
* ... truncation of the actual fractional part of the floating_point_t value, scaled
* by the precision value
*/
bool is_negative;
};
static const floating_point_t powers_of_10[PRINTF_MAX_PRECOMPUTED_POWER_OF_10 + 1] = {
1e00, 1e01, 1e02, 1e03, 1e04, 1e05, 1e06, 1e07, 1e08, 1e09, 1e10
#if PRINTF_MAX_PRECOMPUTED_POWER_OF_10 > 10
, 1e11, 1e12, 1e13, 1e14, 1e15, 1e16, 1e17
#endif
};
/*
* Note: This value does not mean that all floating-point values printed with the
* library will be correct up to this precision; it is just an upper-bound for
* avoiding buffer overruns and such
*/
#define PRINTF_MAX_SUPPORTED_PRECISION (NUM_DECIMAL_DIGITS_IN_INT64_T - 1)
/*
* Break up a non-negative, finite, floating-point number into two integral
* parts of its decimal representation: The number up to the decimal point,
* and the number appearing after that point - whose number of digits
* corresponds to the precision value. Example: The components of 12.621
* are 12 and 621 for precision 3, or 12 and 62 for precision 2.
*/
static struct floating_point_components get_components(floating_point_t number, printf_size_t precision)
{
struct floating_point_components number_;
floating_point_t abs_number;
floating_point_t scaled_remainder;
floating_point_t remainder;
const floating_point_t one_half = (floating_point_t) 0.5;
number_.is_negative = get_sign_bit(number);
abs_number = SIGN(number_.is_negative, number);
number_.integral = (int_fast64_t) abs_number;
scaled_remainder = (abs_number - (floating_point_t) number_.integral) * powers_of_10[precision];
number_.fractional = (int_fast64_t) scaled_remainder; /* for precision == 0U, this will be 0 */
remainder = scaled_remainder - (floating_point_t) number_.fractional;
if ((remainder > one_half) ||
/* Banker's rounding, i.e. round half to even: 1.5 -> 2, but 2.5 -> 2 */
((remainder == one_half) && (number_.fractional & 1U))) {
++number_.fractional;
}
if ((floating_point_t) number_.fractional >= powers_of_10[precision]) {
number_.fractional = 0;
++number_.integral;
}
if (precision == 0U) {
remainder = abs_number - (floating_point_t) number_.integral;
if ((remainder == one_half) && (number_.integral & 1U)) {
/*
* Banker's rounding, i.e. round half to even:
* 1.5 -> 2, but 2.5 -> 2
*/
++number_.integral;
}
}
return number_;
}
#if PRINTF_SUPPORT_EXPONENTIAL_SPECIFIERS
struct scaling_factor {
floating_point_t raw_factor;
bool multiply; /* if true, need to multiply by raw_factor; otherwise need to divide by it */
};
static floating_point_t apply_scaling(floating_point_t num, struct scaling_factor normalization)
{
return normalization.multiply ? num * normalization.raw_factor : num / normalization.raw_factor;
}
static floating_point_t unapply_scaling(floating_point_t normalized, struct scaling_factor normalization)
{
#ifdef __GNUC__
/* accounting for a static analysis bug in GCC 6.x and earlier */
#pragma GCC diagnostic push
#if !defined(__has_warning)
#pragma GCC diagnostic ignored "-Wmaybe-uninitialized"
#elif __has_warning("-Wmaybe-uninitialized")
#pragma GCC diagnostic ignored "-Wmaybe-uninitialized"
#endif
#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, floating_point_t 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 floating_point_components get_normalized_components(bool negative, printf_size_t precision, floating_point_t non_normalized, struct scaling_factor normalization, int floored_exp10)
{
struct floating_point_components components;
floating_point_t scaled;
bool close_to_representation_extremum;
floating_point_t remainder;
floating_point_t prec_power_of_10;
struct scaling_factor account_for_precision;
floating_point_t scaled_remainder;
const floating_point_t rounding_threshold = 0.5;
components.is_negative = negative;
scaled = apply_scaling(non_normalized, normalization);
close_to_representation_extremum = ( (-floored_exp10 + (int) precision) >= FP_TYPE_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(SIGN(negative, scaled), precision);
}
components.integral = (int_fast64_t) scaled;
remainder = non_normalized - unapply_scaling((floating_point_t) components.integral, normalization);
prec_power_of_10 = powers_of_10[precision];
account_for_precision = update_normalization(normalization, prec_power_of_10);
scaled_remainder = apply_scaling(remainder, account_for_precision);
components.fractional = (int_fast64_t) scaled_remainder; /* when precision == 0, the assigned value should be 0 */
scaled_remainder -= (floating_point_t) 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 ((floating_point_t) components.fractional >= prec_power_of_10) {
components.fractional = 0;
++components.integral;
}
return components;
}
#endif /* PRINTF_SUPPORT_EXPONENTIAL_SPECIFIERS */
static void print_broken_up_decimal(
struct floating_point_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 void print_decimal_number(output_gadget_t* output, floating_point_t number, printf_size_t precision, printf_size_t width, printf_flags_t flags, char* buf, printf_size_t len)
{
struct floating_point_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(floating_point_t x)
{
int n;
if (x >= 0) { return (int) x; }
n = (int) x;
return ( ((floating_point_t) 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 floating_point_t log10_of_positive(floating_point_t 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.
*/
floating_point_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);
floating_point_t z;
/* drop the exponent, so dwba.F comes into the range [1,2) */
dwba.U = (dwba.U & (((printf_fp_uint_t) (1) << FP_TYPE_STORED_MANTISSA_BITS) - 1U)) |
((printf_fp_uint_t) FP_TYPE_BASE_EXPONENT << FP_TYPE_STORED_MANTISSA_BITS);
z = (dwba.F - (floating_point_t) 1.5);
return (
/* Taylor expansion around 1.5: */
(floating_point_t) 0.1760912590556812420 /* Expansion term 0: ln(1.5) / ln(10) */
+ z * (floating_point_t) 0.2895296546021678851 /* Expansion term 1: (M - 1.5) * 2/3 / ln(10) */
#if PRINTF_LOG10_TAYLOR_TERMS > 2
- z*z * (floating_point_t) 0.0965098848673892950 /* Expansion term 2: (M - 1.5)^2 * 2/9 / ln(10) */
#if PRINTF_LOG10_TAYLOR_TERMS > 3
+ z*z*z * (floating_point_t) 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 */
+ (floating_point_t) exp2 * (floating_point_t) 0.30102999566398119521 /* = exp2 * log_10(2) = exp2 * ln(2)/ln(10) */
);
}
static floating_point_t pow10_of_int(int floored_exp10)
{
floating_point_with_bit_access dwba;
int exp2;
floating_point_t z;
floating_point_t z2;
/* A crude hack for avoiding undesired behavior with barely-normal or slightly-subnormal values. */
if (floored_exp10 == FP_TYPE_MAX_SUBNORMAL_EXPONENT_OF_10) {
return FP_TYPE_MAX_SUBNORMAL_POWER_OF_10;
}
/* Compute 10^(floored_exp10) but (try to) make sure that doesn't overflow */
exp2 = bastardized_floor(floored_exp10 * (floating_point_t) 3.321928094887362 + (floating_point_t) 0.5);
z = floored_exp10 * (floating_point_t) 2.302585092994046 - exp2 * (floating_point_t) 0.6931471805599453;
z2 = z * z;
dwba.U = ((printf_fp_uint_t)(exp2) + FP_TYPE_BASE_EXPONENT) << FP_TYPE_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 void print_exponential_number(output_gadget_t* output, floating_point_t 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 */
floating_point_t abs_number = SIGN(negative, number);
int floored_exp10;
bool abs_exp10_covered_by_powers_table;
struct scaling_factor normalization;
struct floating_point_components decimal_part_components;
int original_floored_exp10;
bool fall_back_to_decimal_only_mode;
printf_size_t exp10_part_width;
printf_size_t decimal_part_width;
printf_size_t printed_exponential_start_pos;
/* Determine the decimal exponent */
if (abs_number == (floating_point_t) 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 {
floating_point_t exp10 = log10_of_positive(abs_number);
floating_point_t p10;
floored_exp10 = bastardized_floor(exp10);
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;
}
if (flags & FLAGS_ADAPT_EXP) {
/*
* Note: For now, still assuming we _don't_ fall-back to "%f" mode; we can't decide
* that until we've established the exact exponent.
*/
/*
* In "%g" mode, "precision" is the number of _significant digits_; we must
* "translate" that to an actual number of decimal digits.
*/
precision = (precision > 1) ? (precision - 1U) : 0U;
flags |= FLAGS_PRECISION; /* make sure print_broken_up_decimal respects our choice */
}
/*
* 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".
*/
#ifdef __GNUC__
/* accounting for a static analysis bug in GCC 6.x and earlier */
#pragma GCC diagnostic push
#if !defined(__has_warning)
#pragma GCC diagnostic ignored "-Wmaybe-uninitialized"
#elif __has_warning("-Wmaybe-uninitialized")
#pragma GCC diagnostic ignored "-Wmaybe-uninitialized"
#endif
#endif
normalization.multiply = (floored_exp10 < 0 && abs_exp10_covered_by_powers_table);
#ifdef __GNUC__
#pragma GCC diagnostic pop
#endif
decimal_part_components =
(floored_exp10 == 0) ?
get_components(SIGN(negative, 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
* (and saving the floored_exp10 in case we'll need to undo the roll-over).
*/
original_floored_exp10 = floored_exp10;
if (decimal_part_components.integral >= 10) {
floored_exp10++;
decimal_part_components.integral = 1;
decimal_part_components.fractional = 0;
}
/*
* Should we want to fall-back to "%f" mode, and only print the decimal part?
* (and remember we have decreased "precision" by 1
*/
fall_back_to_decimal_only_mode = (flags & FLAGS_ADAPT_EXP) && (floored_exp10 >= -4) && (floored_exp10 < (int) precision + 1);
if (fall_back_to_decimal_only_mode) {
precision = ((int) precision > floored_exp10) ? (unsigned) ((int) precision - floored_exp10) : 0U;
/* Redo some work :-) */
floored_exp10 = original_floored_exp10;
decimal_part_components = get_components(SIGN(negative, abs_number), precision);
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 */
if (precision > 0U) { precision--; }
/* ... and it should already be the case that decimal_part_components.fractional == 0 */
}
/* TODO: What about rollover strictly within the fractional part? */
}
/*
* 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
*/
exp10_part_width = fall_back_to_decimal_only_mode ? 0U : (PRINTF_ABS(floored_exp10) < 100) ? 4U : 5U;
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);
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 void print_floating_point(output_gadget_t* output, floating_point_t 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 < -FP_TYPE_MAX) {
out_rev_(output, "fni-", 4, width, flags);
return;
}
if (value > FP_TYPE_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 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 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)
{
printf_flags_t flags;
printf_size_t width;
printf_size_t precision;
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);
flags = parse_flags(&format);
/* evaluate width field */
width = 0U;
if (is_digit_(*format)) {
/*
* Note: If the width is negative, we've already parsed its
* sign character '-' as a FLAG_LEFT
*/
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 */
precision = 0U;
if (*format == '.') {
flags |= FLAGS_PRECISION;
ADVANCE_IN_FORMAT_STRING(format);
if (*format == '-') {
do {
ADVANCE_IN_FORMAT_STRING(format);
} while (is_digit_(*format));
flags &= ~FLAGS_PRECISION;
}
else if (is_digit_(*format)) {
precision = atou_(&format);
}
else if (*format == '*') {
const int precision_ = va_arg(args, int);
if (precision_ < 0) {
flags &= ~FLAGS_PRECISION;
}
else {
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 'L' :
flags |= FLAGS_LONG_DOUBLE;
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(int) ) ? FLAGS_INT : (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(int) ) ? FLAGS_INT : (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' : {
numeric_base_t base;
if (*format == 'd' || *format == 'i') {
flags |= FLAGS_SIGNED;
}
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' : {
floating_point_t value = (floating_point_t) (flags & FLAGS_LONG_DOUBLE ? va_arg(args, long double) : va_arg(args, double));
if (*format == 'F') flags |= FLAGS_UPPERCASE;
print_floating_point(output, value, precision, width, flags, PRINTF_PREFER_DECIMAL);
format++;
break;
}
#endif
#if PRINTF_SUPPORT_EXPONENTIAL_SPECIFIERS
case 'e':
case 'E':
case 'g':
case 'G': {
floating_point_t value = (floating_point_t) (flags & FLAGS_LONG_DOUBLE ? va_arg(args, long double) : va_arg(args, double));
if ((*format == 'g')||(*format == 'G')) flags |= FLAGS_ADAPT_EXP;
if ((*format == 'E')||(*format == 'G')) flags |= FLAGS_UPPERCASE;
print_floating_point(output, value, 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' : {
uintptr_t value;
width = sizeof(void*) * 2U + 2; /* 2 hex chars per byte + the "0x" prefix */
flags |= FLAGS_ZEROPAD | FLAGS_POINTER;
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 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;
}
/*===========================================================================*/
int vprintf_(const char* format, va_list arg)
{
output_gadget_t gadget = extern_putchar_gadget();
return vsnprintf_impl(&gadget, format, arg);
}
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);
}
int vsprintf_(char* s, const char* format, va_list arg)
{
return vsnprintf_(s, PRINTF_MAX_POSSIBLE_BUFFER_SIZE, format, arg);
}
int vfctprintf(void (*out)(char c, void* extra_arg), void* extra_arg, const char* format, va_list arg)
{
output_gadget_t gadget;
if (out == NULL) { return 0; }
gadget = function_gadget(out, extra_arg);
return vsnprintf_impl(&gadget, format, arg);
}
int printf_(const char* format, ...)
{
int ret;
va_list args;
va_start(args, format);
ret = vprintf_(format, args);
va_end(args);
return ret;
}
int sprintf_(char* s, const char* format, ...)
{
int ret;
va_list args;
va_start(args, format);
ret = vsprintf_(s, format, args);
va_end(args);
return ret;
}
int snprintf_(char* s, size_t n, const char* format, ...)
{
int ret;
va_list args;
va_start(args, format);
ret = vsnprintf_(s, n, format, args);
va_end(args);
return ret;
}
int fctprintf(void (*out)(char c, void* extra_arg), void* extra_arg, const char* format, ...)
{
int ret;
va_list args;
va_start(args, format);
ret = vfctprintf(out, extra_arg, format, args);
va_end(args);
return ret;
}
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