/*
* Copyright (c) 2001-2004 Jakub Jermar
* Copyright (c) 2006 Josef Cejka
* Copyright (c) 2009 Martin Decky
* Copyright (c) 2025 Jiří Zárevúcky
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* - Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* - The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/** @addtogroup libc
* @{
*/
/**
* @file
* @brief Printing functions.
*/
#include <_bits/uchar.h>
#include <_bits/wint_t.h>
#include <assert.h>
#include <ctype.h>
#include <errno.h>
#include <limits.h>
#include <macros.h>
#include <printf_core.h>
#include <stddef.h>
#include <stdint.h>
#include <stdlib.h>
#include <str.h>
/* Disable float support in kernel, because we usually disable floating operations there. */
#if __STDC_HOSTED__
#define HAS_FLOAT
#endif
#ifdef HAS_FLOAT
#include <double_to_str.h>
#include <ieee_double.h>
#endif
/** show prefixes 0x or 0 */
#define __PRINTF_FLAG_PREFIX 0x00000001
/** show the decimal point even if no fractional digits present */
#define __PRINTF_FLAG_DECIMALPT 0x00000001
/** signed / unsigned number */
#define __PRINTF_FLAG_SIGNED 0x00000002
/** print leading zeroes */
#define __PRINTF_FLAG_ZEROPADDED 0x00000004
/** align to left */
#define __PRINTF_FLAG_LEFTALIGNED 0x00000010
/** always show + sign */
#define __PRINTF_FLAG_SHOWPLUS 0x00000020
/** print space instead of plus */
#define __PRINTF_FLAG_SPACESIGN 0x00000040
/** show big characters */
#define __PRINTF_FLAG_BIGCHARS 0x00000080
/** number has - sign */
#define __PRINTF_FLAG_NEGATIVE 0x00000100
/** don't print trailing zeros in the fractional part */
#define __PRINTF_FLAG_NOFRACZEROS 0x00000200
/**
* Buffer big enough for 64-bit number printed in base 2.
*/
#define PRINT_NUMBER_BUFFER_SIZE 64
/** Get signed or unsigned integer argument */
#define PRINTF_GET_INT_ARGUMENT(type, ap, flags) \
({ \
unsigned type res; \
\
if ((flags) & __PRINTF_FLAG_SIGNED) { \
signed type arg = va_arg((ap), signed type); \
\
if (arg < 0) { \
res = -arg; \
(flags) |= __PRINTF_FLAG_NEGATIVE; \
} else \
res = arg; \
} else \
res = va_arg((ap), unsigned type); \
\
res; \
})
/** Enumeration of possible arguments types.
*/
typedef enum {
PrintfQualifierByte = 0,
PrintfQualifierShort,
PrintfQualifierInt,
PrintfQualifierLong,
PrintfQualifierLongLong,
PrintfQualifierPointer,
} qualifier_t;
static const char _digits_small[] = "0123456789abcdef";
static const char _digits_big[] = "0123456789ABCDEF";
static const char _nullstr[] = "(NULL)";
static const char _replacement[] = u8"�";
static const char _spaces[] = " ";
static const char _zeros[] = "000000000000000000000000000000000000000000000000";
static void _set_errno(errno_t rc)
{
#ifdef errno
errno = rc;
#endif
}
static size_t _utf8_bytes(char32_t c)
{
if (c < 0x80)
return 1;
if (c < 0x800)
return 2;
if (c < 0xD800)
return 3;
/* Surrogate code points, invalid in UTF-32. */
if (c < 0xE000)
return sizeof(_replacement) - 1;
if (c < 0x10000)
return 3;
if (c < 0x110000)
return 4;
/* Invalid character. */
return sizeof(_replacement) - 1;
}
/** Counts characters and utf8 bytes in a wide string up to a byte limit.
* @param max_bytes Byte length limit for string's utf8 conversion.
* @param[out] len The number of wide characters
* @return Number of utf8 bytes that the first *len characters in the string
* will convert to. Will always be less than max_bytes.
*/
static size_t _utf8_wstr_bytes_len(char32_t *s, size_t max_bytes, size_t *len)
{
size_t bytes = 0;
size_t i;
for (i = 0; bytes < max_bytes && s[i]; i++) {
size_t next = _utf8_bytes(s[i]);
if (max_bytes - bytes < next)
break;
bytes += next;
}
*len = i;
return bytes;
}
#define TRY(expr) ({ errno_t rc = (expr); if (rc != EOK) return rc; })
static inline void _saturating_add(size_t *a, size_t b)
{
size_t s = *a + b;
/* Only works because size_t is unsigned. */
*a = (s < b) ? SIZE_MAX : s;
}
static errno_t _write_bytes(const char *buf, size_t n, printf_spec_t *ps,
size_t *written_bytes)
{
errno_t rc = ps->write(buf, n, ps->data);
if (rc != EOK)
return rc;
_saturating_add(written_bytes, n);
return EOK;
}
/** Write one UTF-32 character. */
static errno_t _write_uchar(char32_t ch, printf_spec_t *ps,
size_t *written_bytes)
{
char utf8[4];
size_t offset = 0;
if (chr_encode(ch, utf8, &offset, sizeof(utf8)) == EOK)
return _write_bytes(utf8, offset, ps, written_bytes);
/* Invalid character. */
return _write_bytes(_replacement, sizeof(_replacement) - 1, ps, written_bytes);
}
/** Write n UTF-32 characters. */
static errno_t _write_chars(const char32_t *buf, size_t n, printf_spec_t *ps,
size_t *written_bytes)
{
for (size_t i = 0; i < n; i++)
TRY(_write_uchar(buf[i], ps, written_bytes));
return EOK;
}
static errno_t _write_char(char c, printf_spec_t *ps, size_t *written_bytes)
{
return _write_bytes(&c, 1, ps, written_bytes);
}
static errno_t _write_spaces(size_t n, printf_spec_t *ps, size_t *written_bytes)
{
size_t max_spaces = sizeof(_spaces) - 1;
while (n > max_spaces) {
TRY(_write_bytes(_spaces, max_spaces, ps, written_bytes));
n -= max_spaces;
}
return _write_bytes(_spaces, n, ps, written_bytes);
}
static errno_t _write_zeros(size_t n, printf_spec_t *ps, size_t *written_bytes)
{
size_t max_zeros = sizeof(_zeros) - 1;
while (n > max_zeros) {
TRY(_write_bytes(_zeros, max_zeros, ps, written_bytes));
n -= max_zeros;
}
return _write_bytes(_zeros, n, ps, written_bytes);
}
/** Print one formatted ASCII character.
*
* @param ch Character to print.
* @param width Width modifier.
* @param flags Flags that change the way the character is printed.
*/
static errno_t _format_char(const char c, size_t width, uint32_t flags,
printf_spec_t *ps, size_t *written_bytes)
{
size_t bytes = 1;
if (width <= bytes)
return _write_char(c, ps, written_bytes);
if (flags & __PRINTF_FLAG_LEFTALIGNED) {
TRY(_write_char(c, ps, written_bytes));
TRY(_write_spaces(width - bytes, ps, written_bytes));
} else {
TRY(_write_spaces(width - bytes, ps, written_bytes));
TRY(_write_char(c, ps, written_bytes));
}
return EOK;
}
/** Print one formatted wide character.
*
* @param ch Character to print.
* @param width Width modifier.
* @param flags Flags that change the way the character is printed.
*/
static errno_t _format_uchar(const char32_t ch, size_t width, uint32_t flags,
printf_spec_t *ps, size_t *written_bytes)
{
/*
* All widths in printf() are specified in bytes. It might seem nonsensical
* with unicode text, but that's the way the function is defined. The width
* is barely useful if you want column alignment in terminal, but keep in
* mind that counting code points is only marginally better for that.
* Characters can span more than one unicode code point, even in languages
* based on latin alphabet, and a single unicode code point can occupy two
* spaces in east asian scripts.
*
* What the width can actually be useful for is padding, when you need the
* output to fill an exact number of bytes in a file. That use would break
* if we did our own thing here.
*/
size_t bytes = _utf8_bytes(ch);
if (width <= bytes)
return _write_uchar(ch, ps, written_bytes);
if (flags & __PRINTF_FLAG_LEFTALIGNED) {
TRY(_write_uchar(ch, ps, written_bytes));
TRY(_write_spaces(width - bytes, ps, written_bytes));
} else {
TRY(_write_spaces(width - bytes, ps, written_bytes));
TRY(_write_uchar(ch, ps, written_bytes));
}
return EOK;
}
/** Print string.
*
* @param str String to be printed.
* @param width Width modifier.
* @param precision Precision modifier.
* @param flags Flags that modify the way the string is printed.
*/
static errno_t _format_cstr(const char *str, size_t width, int precision,
uint32_t flags, printf_spec_t *ps, size_t *written_bytes)
{
if (str == NULL)
str = _nullstr;
/* Negative precision == unspecified. */
size_t max_bytes = (precision < 0) ? SIZE_MAX : (size_t) precision;
size_t bytes = str_nsize(str, max_bytes);
if (width <= bytes)
return _write_bytes(str, bytes, ps, written_bytes);
if (flags & __PRINTF_FLAG_LEFTALIGNED) {
TRY(_write_bytes(str, bytes, ps, written_bytes));
TRY(_write_spaces(width - bytes, ps, written_bytes));
} else {
TRY(_write_spaces(width - bytes, ps, written_bytes));
TRY(_write_bytes(str, bytes, ps, written_bytes));
}
return EOK;
}
/** Print wide string.
*
* @param str Wide string to be printed.
* @param width Width modifier.
* @param precision Precision modifier.
* @param flags Flags that modify the way the string is printed.
*/
static errno_t _format_wstr(char32_t *str, size_t width, int precision,
uint32_t flags, printf_spec_t *ps, size_t *written_bytes)
{
if (!str)
return _format_cstr(_nullstr, width, precision, flags, ps, written_bytes);
/* Width and precision are always byte-based. See _format_uchar() */
/* Negative precision == unspecified. */
size_t max_bytes = (precision < 0) ? SIZE_MAX : (size_t) precision;
size_t len;
size_t bytes = _utf8_wstr_bytes_len(str, max_bytes, &len);
if (width <= bytes)
return _write_chars(str, len, ps, written_bytes);
if (flags & __PRINTF_FLAG_LEFTALIGNED) {
TRY(_write_chars(str, len, ps, written_bytes));
TRY(_write_spaces(width - bytes, ps, written_bytes));
} else {
TRY(_write_spaces(width - bytes, ps, written_bytes));
TRY(_write_chars(str, len, ps, written_bytes));
}
return EOK;
}
static char _sign(uint32_t flags)
{
if (!(flags & __PRINTF_FLAG_SIGNED))
return 0;
if (flags & __PRINTF_FLAG_NEGATIVE)
return '-';
if (flags & __PRINTF_FLAG_SHOWPLUS)
return '+';
if (flags & __PRINTF_FLAG_SPACESIGN)
return ' ';
return 0;
}
/** Print a number in a given base.
*
* Print significant digits of a number in given base.
*
* @param num Number to print.
* @param width Width modifier.
* @param precision Precision modifier.
* @param base Base to print the number in (must be between 2 and 16).
* @param flags Flags that modify the way the number is printed.
*/
static errno_t _format_number(uint64_t num, size_t width, int precision, int base,
uint32_t flags, printf_spec_t *ps, size_t *written_bytes)
{
assert(base >= 2 && base <= 16);
/* Default precision for numeric output is 1. */
size_t min_digits = (precision < 0) ? 1 : precision;
bool bigchars = flags & __PRINTF_FLAG_BIGCHARS;
bool prefix = flags & __PRINTF_FLAG_PREFIX;
bool left_aligned = flags & __PRINTF_FLAG_LEFTALIGNED;
bool zero_padded = flags & __PRINTF_FLAG_ZEROPADDED;
const char *digits = bigchars ? _digits_big : _digits_small;
char buffer[PRINT_NUMBER_BUFFER_SIZE];
char *end = &buffer[PRINT_NUMBER_BUFFER_SIZE];
/* Write number to the buffer. */
int offset = 0;
while (num > 0) {
end[--offset] = digits[num % base];
num /= base;
}
char *number = &end[offset];
size_t number_len = end - number;
char sign = _sign(flags);
if (left_aligned) {
/* Space padded right-aligned. */
size_t real_size = max(number_len, min_digits);
if (sign) {
TRY(_write_char(sign, ps, written_bytes));
real_size++;
}
if (prefix && base == 2 && number_len > 0) {
TRY(_write_bytes(bigchars ? "0B" : "0b", 2, ps, written_bytes));
real_size += 2;
}
if (prefix && base == 16 && number_len > 0) {
TRY(_write_bytes(bigchars ? "0X" : "0x", 2, ps, written_bytes));
real_size += 2;
}
if (min_digits > number_len) {
TRY(_write_zeros(min_digits - number_len, ps, written_bytes));
} else if (prefix && base == 8) {
TRY(_write_zeros(1, ps, written_bytes));
real_size++;
}
TRY(_write_bytes(number, number_len, ps, written_bytes));
if (width > real_size)
TRY(_write_spaces(width - real_size, ps, written_bytes));
return EOK;
}
/* Zero padded number (ignored when left aligned or if precision is specified). */
if (precision < 0 && zero_padded) {
size_t real_size = number_len;
if (sign) {
TRY(_write_char(sign, ps, written_bytes));
real_size++;
}
if (prefix && base == 2 && number_len > 0) {
TRY(_write_bytes(bigchars ? "0B" : "0b", 2, ps, written_bytes));
real_size += 2;
}
if (prefix && base == 16 && number_len > 0) {
TRY(_write_bytes(bigchars ? "0X" : "0x", 2, ps, written_bytes));
real_size += 2;
}
if (width > real_size)
TRY(_write_zeros(width - real_size, ps, written_bytes));
else if (number_len == 0 || (prefix && base == 8))
TRY(_write_char('0', ps, written_bytes));
return _write_bytes(number, number_len, ps, written_bytes);
}
/* Space padded right-aligned. */
size_t real_size = max(number_len, min_digits);
if (sign)
real_size++;
if (prefix && (base == 2 || base == 16) && number_len > 0)
real_size += 2;
if (prefix && base == 8 && number_len >= min_digits)
real_size += 1;
if (width > real_size)
TRY(_write_spaces(width - real_size, ps, written_bytes));
if (sign)
TRY(_write_char(sign, ps, written_bytes));
if (prefix && base == 2 && number_len > 0)
TRY(_write_bytes(bigchars ? "0B" : "0b", 2, ps, written_bytes));
if (prefix && base == 16 && number_len > 0)
TRY(_write_bytes(bigchars ? "0X" : "0x", 2, ps, written_bytes));
if (min_digits > number_len)
TRY(_write_zeros(min_digits - number_len, ps, written_bytes));
else if (prefix && base == 8)
TRY(_write_char('0', ps, written_bytes));
return _write_bytes(number, number_len, ps, written_bytes);
}
#ifdef HAS_FLOAT
/** Unformatted double number string representation. */
typedef struct {
/** Buffer with len digits, no sign or leading zeros. */
char *str;
/** Number of digits in str. */
int len;
/** Decimal exponent, ie number = str * 10^dec_exp */
int dec_exp;
/** True if negative. */
bool neg;
} double_str_t;
/** Returns the sign character or 0 if no sign should be printed. */
static char _get_sign_char(bool negative, uint32_t flags)
{
if (negative) {
return '-';
} else if (flags & __PRINTF_FLAG_SHOWPLUS) {
return '+';
} else if (flags & __PRINTF_FLAG_SPACESIGN) {
return ' ';
} else {
return 0;
}
}
/** Prints a special double (ie NaN, infinity) padded to width characters. */
static errno_t _format_special(ieee_double_t val, int width, uint32_t flags,
printf_spec_t *ps, size_t *written_bytes)
{
assert(val.is_special);
char sign = _get_sign_char(val.is_negative, flags);
const int str_len = 3;
const char *str;
if (flags & __PRINTF_FLAG_BIGCHARS) {
str = val.is_infinity ? "INF" : "NAN";
} else {
str = val.is_infinity ? "inf" : "nan";
}
int padding_len = max(0, width - ((sign ? 1 : 0) + str_len));
/* Leading padding. */
if (!(flags & __PRINTF_FLAG_LEFTALIGNED))
TRY(_write_spaces(padding_len, ps, written_bytes));
if (sign)
TRY(_write_char(sign, ps, written_bytes));
TRY(_write_bytes(str, str_len, ps, written_bytes));
/* Trailing padding. */
if (flags & __PRINTF_FLAG_LEFTALIGNED)
TRY(_write_spaces(padding_len, ps, written_bytes));
return EOK;
}
/** Trims trailing zeros but leaves a single "0" intact. */
static void _fp_trim_trailing_zeros(char *buf, int *len, int *dec_exp)
{
/* Cut the zero off by adjusting the exponent. */
while (2 <= *len && '0' == buf[*len - 1]) {
--*len;
++*dec_exp;
}
}
/** Textually round up the last digit thereby eliminating it. */
static void _fp_round_up(char *buf, int *len, int *dec_exp)
{
assert(1 <= *len);
char *last_digit = &buf[*len - 1];
int carry = ('5' <= *last_digit);
/* Cut the digit off by adjusting the exponent. */
--*len;
++*dec_exp;
--last_digit;
if (carry) {
/* Skip all the digits to cut off/round to zero. */
while (buf <= last_digit && '9' == *last_digit) {
--last_digit;
}
/* last_digit points to the last digit to round but not '9' */
if (buf <= last_digit) {
*last_digit += 1;
int new_len = last_digit - buf + 1;
*dec_exp += *len - new_len;
*len = new_len;
} else {
/* All len digits rounded to 0. */
buf[0] = '1';
*dec_exp += *len;
*len = 1;
}
} else {
/* The only digit was rounded to 0. */
if (last_digit < buf) {
buf[0] = '0';
*dec_exp = 0;
*len = 1;
}
}
}
/** Format and print the double string repressentation according
* to the %f specifier.
*/
static errno_t _format_double_str_fixed(double_str_t *val_str, int precision, int width,
uint32_t flags, printf_spec_t *ps, size_t *written_bytes)
{
int len = val_str->len;
char *buf = val_str->str;
int dec_exp = val_str->dec_exp;
assert(0 < len);
assert(0 <= precision);
assert(0 <= dec_exp || -dec_exp <= precision);
/* Number of integral digits to print (at least leading zero). */
int int_len = max(1, len + dec_exp);
char sign = _get_sign_char(val_str->neg, flags);
/* Fractional portion lengths. */
int last_frac_signif_pos = max(0, -dec_exp);
int leading_frac_zeros = max(0, last_frac_signif_pos - len);
int signif_frac_figs = min(last_frac_signif_pos, len);
int trailing_frac_zeros = precision - last_frac_signif_pos;
char *buf_frac = buf + len - signif_frac_figs;
if (flags & __PRINTF_FLAG_NOFRACZEROS)
trailing_frac_zeros = 0;
int frac_len = leading_frac_zeros + signif_frac_figs + trailing_frac_zeros;
bool has_decimal_pt = (0 < frac_len) || (flags & __PRINTF_FLAG_DECIMALPT);
/* Number of non-padding chars to print. */
int num_len = (sign ? 1 : 0) + int_len + (has_decimal_pt ? 1 : 0) + frac_len;
int padding_len = max(0, width - num_len);
/* Leading padding and sign. */
if (!(flags & (__PRINTF_FLAG_LEFTALIGNED | __PRINTF_FLAG_ZEROPADDED)))
TRY(_write_spaces(padding_len, ps, written_bytes));
if (sign)
TRY(_write_char(sign, ps, written_bytes));
if (flags & __PRINTF_FLAG_ZEROPADDED)
TRY(_write_zeros(padding_len, ps, written_bytes));
/* Print the intergral part of the buffer. */
int buf_int_len = min(len, len + dec_exp);
if (0 < buf_int_len) {
TRY(_write_bytes(buf, buf_int_len, ps, written_bytes));
/* Print trailing zeros of the integral part of the number. */
TRY(_write_zeros(int_len - buf_int_len, ps, written_bytes));
} else {
/* Single leading integer 0. */
TRY(_write_char('0', ps, written_bytes));
}
/* Print the decimal point and the fractional part. */
if (has_decimal_pt) {
TRY(_write_char('.', ps, written_bytes));
/* Print leading zeros of the fractional part of the number. */
TRY(_write_zeros(leading_frac_zeros, ps, written_bytes));
/* Print significant digits of the fractional part of the number. */
if (0 < signif_frac_figs)
TRY(_write_bytes(buf_frac, signif_frac_figs, ps, written_bytes));
/* Print trailing zeros of the fractional part of the number. */
TRY(_write_zeros(trailing_frac_zeros, ps, written_bytes));
}
/* Trailing padding. */
if (flags & __PRINTF_FLAG_LEFTALIGNED)
TRY(_write_spaces(padding_len, ps, written_bytes));
return EOK;
}
/** Convert, format and print a double according to the %f specifier.
*
* @param g Double to print.
* @param precision Number of fractional digits to print. If 0 no
* decimal point will be printed unless the flag
* __PRINTF_FLAG_DECIMALPT is specified.
* @param width Minimum number of characters to display. Pads
* with '0' or ' ' depending on the set flags;
* @param flags Printf flags.
* @param ps Printing functions.
*/
static errno_t _format_double_fixed(double g, int precision, int width,
uint32_t flags, printf_spec_t *ps, size_t *written_bytes)
{
if (flags & __PRINTF_FLAG_LEFTALIGNED) {
flags &= ~__PRINTF_FLAG_ZEROPADDED;
}
if (flags & __PRINTF_FLAG_DECIMALPT) {
flags &= ~__PRINTF_FLAG_NOFRACZEROS;
}
ieee_double_t val = extract_ieee_double(g);
if (val.is_special) {
return _format_special(val, width, flags, ps, written_bytes);
}
char buf[MAX_DOUBLE_STR_BUF_SIZE];
const size_t buf_size = MAX_DOUBLE_STR_BUF_SIZE;
double_str_t val_str;
val_str.str = buf;
val_str.neg = val.is_negative;
if (0 <= precision) {
/*
* Request one more digit so we can round the result. The last
* digit it returns may have an error of at most +/- 1.
*/
val_str.len = double_to_fixed_str(val, -1, precision + 1, buf, buf_size,
&val_str.dec_exp);
/*
* Round using the last digit to produce precision fractional digits.
* If less than precision+1 fractional digits were output the last
* digit is definitely inaccurate so also round to get rid of it.
*/
_fp_round_up(buf, &val_str.len, &val_str.dec_exp);
/* Rounding could have introduced trailing zeros. */
if (flags & __PRINTF_FLAG_NOFRACZEROS) {
_fp_trim_trailing_zeros(buf, &val_str.len, &val_str.dec_exp);
}
} else {
/* Let the implementation figure out the proper precision. */
val_str.len = double_to_short_str(val, buf, buf_size, &val_str.dec_exp);
/* Precision needed for the last significant digit. */
precision = max(0, -val_str.dec_exp);
}
return _format_double_str_fixed(&val_str, precision, width, flags, ps, written_bytes);
}
/** Prints the decimal exponent part of a %e specifier formatted number. */
static errno_t _format_exponent(int exp_val, uint32_t flags, printf_spec_t *ps,
size_t *written_bytes)
{
char exp_ch = (flags & __PRINTF_FLAG_BIGCHARS) ? 'E' : 'e';
TRY(_write_char(exp_ch, ps, written_bytes));
char exp_sign = (exp_val < 0) ? '-' : '+';
TRY(_write_char(exp_sign, ps, written_bytes));
/* Print the exponent. */
exp_val = abs(exp_val);
char exp_str[4] = { 0 };
exp_str[0] = '0' + exp_val / 100;
exp_str[1] = '0' + (exp_val % 100) / 10;
exp_str[2] = '0' + (exp_val % 10);
int exp_len = (exp_str[0] == '0') ? 2 : 3;
const char *exp_str_start = &exp_str[3] - exp_len;
return _write_bytes(exp_str_start, exp_len, ps, written_bytes);
}
/** Format and print the double string repressentation according
* to the %e specifier.
*/
static errno_t _format_double_str_scient(double_str_t *val_str, int precision,
int width, uint32_t flags, printf_spec_t *ps, size_t *written_bytes)
{
int len = val_str->len;
int dec_exp = val_str->dec_exp;
char *buf = val_str->str;
assert(0 < len);
char sign = _get_sign_char(val_str->neg, flags);
bool has_decimal_pt = (0 < precision) || (flags & __PRINTF_FLAG_DECIMALPT);
int dec_pt_len = has_decimal_pt ? 1 : 0;
/* Fractional part lengths. */
int signif_frac_figs = len - 1;
int trailing_frac_zeros = precision - signif_frac_figs;
if (flags & __PRINTF_FLAG_NOFRACZEROS) {
trailing_frac_zeros = 0;
}
int frac_len = signif_frac_figs + trailing_frac_zeros;
int exp_val = dec_exp + len - 1;
/* Account for exponent sign and 'e'; minimum 2 digits. */
int exp_len = 2 + (abs(exp_val) >= 100 ? 3 : 2);
/* Number of non-padding chars to print. */
int num_len = (sign ? 1 : 0) + 1 + dec_pt_len + frac_len + exp_len;
int padding_len = max(0, width - num_len);
if (!(flags & (__PRINTF_FLAG_LEFTALIGNED | __PRINTF_FLAG_ZEROPADDED)))
TRY(_write_spaces(padding_len, ps, written_bytes));
if (sign)
TRY(_write_char(sign, ps, written_bytes));
if (flags & __PRINTF_FLAG_ZEROPADDED)
TRY(_write_zeros(padding_len, ps, written_bytes));
/* Single leading integer. */
TRY(_write_char(buf[0], ps, written_bytes));
/* Print the decimal point and the fractional part. */
if (has_decimal_pt) {
TRY(_write_char('.', ps, written_bytes));
/* Print significant digits of the fractional part of the number. */
if (0 < signif_frac_figs)
TRY(_write_bytes(buf + 1, signif_frac_figs, ps, written_bytes));
/* Print trailing zeros of the fractional part of the number. */
TRY(_write_zeros(trailing_frac_zeros, ps, written_bytes));
}
/* Print the exponent. */
TRY(_format_exponent(exp_val, flags, ps, written_bytes));
if (flags & __PRINTF_FLAG_LEFTALIGNED)
TRY(_write_spaces(padding_len, ps, written_bytes));
return EOK;
}
/** Convert, format and print a double according to the %e specifier.
*
* Note that if g is large, the output may be huge (3e100 prints
* with at least 100 digits).
*
* %e style: [-]d.dddde+dd
* left-justified: [-]d.dddde+dd[space_pad]
* right-justified: [space_pad][-][zero_pad]d.dddde+dd
*
* @param g Double to print.
* @param precision Number of fractional digits to print, ie
* precision + 1 significant digits to display. If 0 no
* decimal point will be printed unless the flag
* __PRINTF_FLAG_DECIMALPT is specified. If negative
* the shortest accurate number will be printed.
* @param width Minimum number of characters to display. Pads
* with '0' or ' ' depending on the set flags;
* @param flags Printf flags.
* @param ps Printing functions.
*/
static errno_t _format_double_scientific(double g, int precision, int width,
uint32_t flags, printf_spec_t *ps, size_t *written_bytes)
{
if (flags & __PRINTF_FLAG_LEFTALIGNED)
flags &= ~__PRINTF_FLAG_ZEROPADDED;
ieee_double_t val = extract_ieee_double(g);
if (val.is_special)
return _format_special(val, width, flags, ps, written_bytes);
char buf[MAX_DOUBLE_STR_BUF_SIZE];
const size_t buf_size = MAX_DOUBLE_STR_BUF_SIZE;
double_str_t val_str;
val_str.str = buf;
val_str.neg = val.is_negative;
if (0 <= precision) {
/*
* Request one more digit (in addition to the leading integer)
* so we can round the result. The last digit it returns may
* have an error of at most +/- 1.
*/
val_str.len = double_to_fixed_str(val, precision + 2, -1, buf, buf_size,
&val_str.dec_exp);
/*
* Round the extra digit to produce precision+1 significant digits.
* If less than precision+2 significant digits were returned the last
* digit is definitely inaccurate so also round to get rid of it.
*/
_fp_round_up(buf, &val_str.len, &val_str.dec_exp);
/* Rounding could have introduced trailing zeros. */
if (flags & __PRINTF_FLAG_NOFRACZEROS) {
_fp_trim_trailing_zeros(buf, &val_str.len, &val_str.dec_exp);
}
} else {
/* Let the implementation figure out the proper precision. */
val_str.len = double_to_short_str(val, buf, buf_size, &val_str.dec_exp);
/* Use all produced digits. */
precision = val_str.len - 1;
}
return _format_double_str_scient(&val_str, precision, width, flags, ps, written_bytes);
}
/** Convert, format and print a double according to the %g specifier.
*
* %g style chooses between %f and %e.
*
* @param g Double to print.
* @param precision Number of significant digits to display; excluding
* any leading zeros from this count. If negative
* the shortest accurate number will be printed.
* @param width Minimum number of characters to display. Pads
* with '0' or ' ' depending on the set flags;
* @param flags Printf flags.
* @param ps Printing functions.
*
* @return The number of characters printed; negative on failure.
*/
static errno_t _format_double_generic(double g, int precision, int width,
uint32_t flags, printf_spec_t *ps, size_t *written_bytes)
{
ieee_double_t val = extract_ieee_double(g);
if (val.is_special)
return _format_special(val, width, flags, ps, written_bytes);
char buf[MAX_DOUBLE_STR_BUF_SIZE];
const size_t buf_size = MAX_DOUBLE_STR_BUF_SIZE;
int dec_exp;
int len;
/* Honor the user requested number of significant digits. */
if (0 <= precision) {
/*
* Do a quick and dirty conversion of a single digit to determine
* the decimal exponent.
*/
len = double_to_fixed_str(val, 1, -1, buf, buf_size, &dec_exp);
assert(0 < len);
precision = max(1, precision);
if (-4 <= dec_exp && dec_exp < precision) {
precision = precision - (dec_exp + 1);
return _format_double_fixed(g, precision, width,
flags | __PRINTF_FLAG_NOFRACZEROS, ps, written_bytes);
} else {
--precision;
return _format_double_scientific(g, precision, width,
flags | __PRINTF_FLAG_NOFRACZEROS, ps, written_bytes);
}
} else {
/* Convert to get the decimal exponent and digit count. */
len = double_to_short_str(val, buf, buf_size, &dec_exp);
assert(0 < len);
if (flags & __PRINTF_FLAG_LEFTALIGNED) {
flags &= ~__PRINTF_FLAG_ZEROPADDED;
}
double_str_t val_str;
val_str.str = buf;
val_str.len = len;
val_str.neg = val.is_negative;
val_str.dec_exp = dec_exp;
int first_digit_pos = len + dec_exp;
int last_digit_pos = dec_exp;
/* The whole number (15 digits max) fits between dec places 15 .. -6 */
if (len <= 15 && -6 <= last_digit_pos && first_digit_pos <= 15) {
/* Precision needed for the last significant digit. */
precision = max(0, -val_str.dec_exp);
return _format_double_str_fixed(&val_str, precision, width, flags, ps, written_bytes);
} else {
/* Use all produced digits. */
precision = val_str.len - 1;
return _format_double_str_scient(&val_str, precision, width, flags, ps, written_bytes);
}
}
}
/** Convert, format and print a double according to the specifier.
*
* Depending on the specifier it prints the double using the styles
* %g, %f or %e by means of print_double_generic(), print_double_fixed(),
* print_double_scientific().
*
* @param g Double to print.
* @param spec Specifier of the style to print in; one of: 'g','G','f','F',
* 'e','E'.
* @param precision Number of fractional digits to display. If negative
* the shortest accurate number will be printed for style %g;
* negative precision defaults to 6 for styles %f, %e.
* @param width Minimum number of characters to display. Pads
* with '0' or ' ' depending on the set flags;
* @param flags Printf flags.
* @param ps Printing functions.
*/
static errno_t _format_double(double g, char spec, int precision, int width,
uint32_t flags, printf_spec_t *ps, size_t *written_chars)
{
switch (spec) {
case 'F':
flags |= __PRINTF_FLAG_BIGCHARS;
/* Fallthrough */
case 'f':
precision = (precision < 0) ? 6 : precision;
return _format_double_fixed(g, precision, width, flags, ps, written_chars);
case 'E':
flags |= __PRINTF_FLAG_BIGCHARS;
/* Fallthrough */
case 'e':
precision = (precision < 0) ? 6 : precision;
return _format_double_scientific(g, precision, width, flags, ps, written_chars);
case 'G':
flags |= __PRINTF_FLAG_BIGCHARS;
/* Fallthrough */
case 'g':
return _format_double_generic(g, precision, width, flags, ps, written_chars);
default:
assert(false);
return -1;
}
}
#endif
static const char *_strchrnul(const char *s, int c)
{
while (*s != c && *s != 0)
s++;
return s;
}
/** Read a sequence of digits from the format string as a number.
* If the number has too many digits to fit in int, returns INT_MAX.
*/
static int _read_num(const char *fmt, size_t *i)
{
const char *s;
unsigned n = 0;
for (s = &fmt[*i]; isdigit(*s); s++) {
unsigned digit = (*s - '0');
/* Check for overflow */
if (n > INT_MAX / 10 || n * 10 > INT_MAX - digit) {
n = INT_MAX;
while (isdigit(*s))
s++;
break;
}
n = n * 10 + digit;
}
*i = s - fmt;
return n;
}
static uint32_t _parse_flags(const char *fmt, size_t *i)
{
uint32_t flags = 0;
while (true) {
switch (fmt[(*i)++]) {
case '#':
flags |= __PRINTF_FLAG_PREFIX;
flags |= __PRINTF_FLAG_DECIMALPT;
continue;
case '-':
flags |= __PRINTF_FLAG_LEFTALIGNED;
continue;
case '+':
flags |= __PRINTF_FLAG_SHOWPLUS;
continue;
case ' ':
flags |= __PRINTF_FLAG_SPACESIGN;
continue;
case '0':
flags |= __PRINTF_FLAG_ZEROPADDED;
continue;
}
--*i;
break;
}
return flags;
}
static bool _eat_char(const char *s, size_t *idx, int c)
{
if (s[*idx] != c)
return false;
(*idx)++;
return true;
}
static qualifier_t _read_qualifier(const char *s, size_t *idx)
{
switch (s[(*idx)++]) {
case 't': /* ptrdiff_t */
case 'z': /* size_t */
if (sizeof(ptrdiff_t) == sizeof(int))
return PrintfQualifierInt;
else
return PrintfQualifierLong;
case 'h':
if (_eat_char(s, idx, 'h'))
return PrintfQualifierByte;
else
return PrintfQualifierShort;
case 'l':
if (_eat_char(s, idx, 'l'))
return PrintfQualifierLongLong;
else
return PrintfQualifierLong;
case 'j':
return PrintfQualifierLongLong;
default:
--*idx;
/* Unspecified */
return PrintfQualifierInt;
}
}
/** Print formatted string.
*
* Print string formatted according to the fmt parameter and variadic arguments.
* Each formatting directive must have the following form:
*
* \% [ FLAGS ] [ WIDTH ] [ .PRECISION ] [ TYPE ] CONVERSION
*
* FLAGS:@n
* - "#" Force to print prefix. For \%o conversion, the prefix is 0, for
* \%x and \%X prefixes are 0x and 0X and for conversion \%b the
* prefix is 0b.
*
* - "-" Align to left.
*
* - "+" Print positive sign just as negative.
*
* - " " If the printed number is positive and "+" flag is not set,
* print space in place of sign.
*
* - "0" Print 0 as padding instead of spaces. Zeroes are placed between
* sign and the rest of the number. This flag is ignored if "-"
* flag is specified.
*
* WIDTH:@n
* - Specify the minimal width of a printed argument. If it is bigger,
* width is ignored. If width is specified with a "*" character instead of
* number, width is taken from parameter list. And integer parameter is
* expected before parameter for processed conversion specification. If
* this value is negative its absolute value is taken and the "-" flag is
* set.
*
* PRECISION:@n
* - Value precision. For numbers it specifies minimum valid numbers.
* Smaller numbers are printed with leading zeroes. Bigger numbers are not
* affected. Strings with more than precision characters are cut off. Just
* as with width, an "*" can be used used instead of a number. An integer
* value is then expected in parameters. When both width and precision are
* specified using "*", the first parameter is used for width and the
* second one for precision.
*
* TYPE:@n
* - "hh" Signed or unsigned char.@n
* - "h" Signed or unsigned short.@n
* - "" Signed or unsigned int (default value).@n
* - "l" Signed or unsigned long int.@n
* If conversion is "c", the character is wint_t (wide character).@n
* If conversion is "s", the string is char32_t * (wide string).@n
* - "ll" Signed or unsigned long long int.@n
* - "z" Signed or unsigned ssize_t or site_t.@n
*
* CONVERSION:@n
* - % Print percentile character itself.
*
* - c Print single character. The character is expected to be plain
* ASCII (e.g. only values 0 .. 127 are valid).@n
* If type is "l", then the character is expected to be wide character
* (e.g. values 0 .. 0x10ffff are valid).
*
* - s Print zero terminated string. If a NULL value is passed as
* value, "(NULL)" is printed instead.@n
* If type is "l", then the string is expected to be wide string.
*
* - P, p Print value of a pointer. Void * value is expected and it is
* printed in hexadecimal notation with prefix (as with
* \%#0.8X / \%#0.8x for 32-bit or \%#0.16lX / \%#0.16lx for 64-bit
* long pointers).
*
* - b Print value as unsigned binary number. Prefix is not printed by
* default. (Nonstandard extension.)
*
* - o Print value as unsigned octal number. Prefix is not printed by
* default.
*
* - d, i Print signed decimal number. There is no difference between d
* and i conversion.
*
* - u Print unsigned decimal number.
*
* - X, x Print hexadecimal number with upper- or lower-case. Prefix is
* not printed by default.
*
* All other characters from fmt except the formatting directives are printed
* verbatim.
*
* @param fmt Format NULL-terminated string.
*
* @return Number of characters printed, negative value on failure.
*
*/
int printf_core(const char *fmt, printf_spec_t *ps, va_list ap)
{
errno_t rc = EOK;
size_t nxt = 0; /* Index of the next character from fmt */
size_t counter = 0; /* Number of characters printed */
while (rc == EOK) {
/* Find the next specifier and write all the bytes before it. */
const char *s = _strchrnul(&fmt[nxt], '%');
size_t bytes = s - &fmt[nxt];
rc = _write_bytes(&fmt[nxt], bytes, ps, &counter);
if (rc != EOK)
break;
nxt += bytes;
/* Check for end of string. */
if (_eat_char(fmt, &nxt, 0))
break;
/* We must be at the start of a specifier. */
bool spec = _eat_char(fmt, &nxt, '%');
assert(spec);
/* Parse modifiers */
uint32_t flags = _parse_flags(fmt, &nxt);
/* Width & '*' operator */
int width = -1;
if (_eat_char(fmt, &nxt, '*')) {
/* Get width value from argument list */
width = va_arg(ap, int);
if (width < 0) {
/* Negative width sets '-' flag */
width = (width == INT_MIN) ? INT_MAX : -width;
flags |= __PRINTF_FLAG_LEFTALIGNED;
}
} else {
width = _read_num(fmt, &nxt);
}
/* Precision and '*' operator */
int precision = -1;
if (_eat_char(fmt, &nxt, '.')) {
if (_eat_char(fmt, &nxt, '*')) {
/* Get precision value from the argument list */
precision = va_arg(ap, int);
/* Negative is treated as omitted. */
if (precision < 0)
precision = -1;
} else {
precision = _read_num(fmt, &nxt);
}
}
qualifier_t qualifier = _read_qualifier(fmt, &nxt);
unsigned int base = 10;
char specifier = fmt[nxt++];
switch (specifier) {
/*
* String and character conversions.
*/
case 's':
if (qualifier == PrintfQualifierLong)
rc = _format_wstr(va_arg(ap, char32_t *), width, precision, flags, ps, &counter);
else
rc = _format_cstr(va_arg(ap, char *), width, precision, flags, ps, &counter);
continue;
case 'c':
if (qualifier == PrintfQualifierLong)
rc = _format_uchar(va_arg(ap, wint_t), width, flags, ps, &counter);
else
rc = _format_char(va_arg(ap, int), width, flags, ps, &counter);
continue;
/*
* Floating point values
*/
case 'G':
case 'g':
case 'F':
case 'f':
case 'E':
case 'e':;
#ifdef HAS_FLOAT
rc = _format_double(va_arg(ap, double), specifier, precision,
width, flags, ps, &counter);
#else
rc = _format_cstr("<float unsupported>", width, -1, 0, ps, &counter);
#endif
continue;
/*
* Integer values
*/
case 'P':
/* Pointer */
flags |= __PRINTF_FLAG_BIGCHARS;
/* Fallthrough */
case 'p':
flags |= __PRINTF_FLAG_PREFIX;
flags |= __PRINTF_FLAG_ZEROPADDED;
base = 16;
qualifier = PrintfQualifierPointer;
break;
case 'b':
base = 2;
break;
case 'o':
base = 8;
break;
case 'd':
case 'i':
flags |= __PRINTF_FLAG_SIGNED;
break;
case 'u':
break;
case 'X':
flags |= __PRINTF_FLAG_BIGCHARS;
/* Fallthrough */
case 'x':
base = 16;
break;
case '%':
/* Percentile itself */
rc = _write_char('%', ps, &counter);
continue;
/*
* Bad formatting.
*/
default:
rc = EINVAL;
continue;
}
/* Print integers */
uint64_t number;
switch (qualifier) {
case PrintfQualifierByte:
number = PRINTF_GET_INT_ARGUMENT(int, ap, flags);
break;
case PrintfQualifierShort:
number = PRINTF_GET_INT_ARGUMENT(int, ap, flags);
break;
case PrintfQualifierInt:
number = PRINTF_GET_INT_ARGUMENT(int, ap, flags);
break;
case PrintfQualifierLong:
number = PRINTF_GET_INT_ARGUMENT(long, ap, flags);
break;
case PrintfQualifierLongLong:
number = PRINTF_GET_INT_ARGUMENT(long long, ap, flags);
break;
case PrintfQualifierPointer:
precision = sizeof(void *) << 1;
number = (uint64_t) (uintptr_t) va_arg(ap, void *);
break;
default:
/* Unknown qualifier */
rc = EINVAL;
continue;
}
rc = _format_number(number, width, precision, base, flags, ps, &counter);
}
if (rc != EOK) {
_set_errno(rc);
return -1;
}
if (counter > INT_MAX) {
_set_errno(EOVERFLOW);
return -1;
}
return (int) counter;
}
/** @}
*/