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nanoprintf.h
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nanoprintf.h
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/* nanoprintf v0.5.3: a tiny embeddable printf replacement written in C.
https://github.com/charlesnicholson/nanoprintf
charles.nicholson+nanoprintf@gmail.com
dual-licensed under 0bsd and unlicense, take your pick. see eof for details. */
#ifndef NANOPRINTF_H_INCLUDED
#define NANOPRINTF_H_INCLUDED
#include <stdarg.h>
#include <stddef.h>
// Define this to fully sandbox nanoprintf inside of a translation unit.
#ifdef NANOPRINTF_VISIBILITY_STATIC
#define NPF_VISIBILITY static
#else
#define NPF_VISIBILITY extern
#endif
#if defined(__clang__) || defined(__GNUC__) || defined(__GNUG__)
#define NPF_PRINTF_ATTR(FORMAT_INDEX, VARGS_INDEX) \
__attribute__((format(printf, FORMAT_INDEX, VARGS_INDEX)))
#else
#define NPF_PRINTF_ATTR(FORMAT_INDEX, VARGS_INDEX)
#endif
// Public API
#ifdef __cplusplus
extern "C" {
#endif
// The npf_ functions all return the number of bytes required to express the
// fully-formatted string, not including the null terminator character.
// The npf_ functions do not return negative values, since the lack of 'l' length
// modifier support makes encoding errors impossible.
NPF_VISIBILITY int npf_snprintf(
char *buffer, size_t bufsz, const char *format, ...) NPF_PRINTF_ATTR(3, 4);
NPF_VISIBILITY int npf_vsnprintf(
char *buffer, size_t bufsz, char const *format, va_list vlist) NPF_PRINTF_ATTR(3, 0);
typedef void (*npf_putc)(int c, void *ctx);
NPF_VISIBILITY int npf_pprintf(
npf_putc pc, void *pc_ctx, char const *format, ...) NPF_PRINTF_ATTR(3, 4);
NPF_VISIBILITY int npf_vpprintf(
npf_putc pc, void *pc_ctx, char const *format, va_list vlist) NPF_PRINTF_ATTR(3, 0);
#ifdef __cplusplus
}
#endif
#endif // NANOPRINTF_H_INCLUDED
/* The implementation of nanoprintf begins here, to be compiled only if
NANOPRINTF_IMPLEMENTATION is defined. In a multi-file library what follows would
be nanoprintf.c. */
#ifdef NANOPRINTF_IMPLEMENTATION
#ifndef NANOPRINTF_IMPLEMENTATION_INCLUDED
#define NANOPRINTF_IMPLEMENTATION_INCLUDED
#include <limits.h>
#include <stdint.h>
// The conversion buffer must fit at least UINT64_MAX in octal format with the leading '0'.
#ifndef NANOPRINTF_CONVERSION_BUFFER_SIZE
#define NANOPRINTF_CONVERSION_BUFFER_SIZE 23
#endif
#if NANOPRINTF_CONVERSION_BUFFER_SIZE < 23
#error The size of the conversion buffer must be at least 23 bytes.
#endif
// Pick reasonable defaults if nothing's been configured.
#if !defined(NANOPRINTF_USE_FIELD_WIDTH_FORMAT_SPECIFIERS) && \
!defined(NANOPRINTF_USE_PRECISION_FORMAT_SPECIFIERS) && \
!defined(NANOPRINTF_USE_FLOAT_FORMAT_SPECIFIERS) && \
!defined(NANOPRINTF_USE_LARGE_FORMAT_SPECIFIERS) && \
!defined(NANOPRINTF_USE_BINARY_FORMAT_SPECIFIERS) && \
!defined(NANOPRINTF_USE_WRITEBACK_FORMAT_SPECIFIERS)
#define NANOPRINTF_USE_FIELD_WIDTH_FORMAT_SPECIFIERS 1
#define NANOPRINTF_USE_PRECISION_FORMAT_SPECIFIERS 1
#define NANOPRINTF_USE_FLOAT_FORMAT_SPECIFIERS 1
#define NANOPRINTF_USE_LARGE_FORMAT_SPECIFIERS 0
#define NANOPRINTF_USE_BINARY_FORMAT_SPECIFIERS 0
#define NANOPRINTF_USE_WRITEBACK_FORMAT_SPECIFIERS 0
#endif
// If anything's been configured, everything must be configured.
#ifndef NANOPRINTF_USE_FIELD_WIDTH_FORMAT_SPECIFIERS
#error NANOPRINTF_USE_FIELD_WIDTH_FORMAT_SPECIFIERS must be #defined to 0 or 1
#endif
#ifndef NANOPRINTF_USE_PRECISION_FORMAT_SPECIFIERS
#error NANOPRINTF_USE_PRECISION_FORMAT_SPECIFIERS must be #defined to 0 or 1
#endif
#ifndef NANOPRINTF_USE_FLOAT_FORMAT_SPECIFIERS
#error NANOPRINTF_USE_FLOAT_FORMAT_SPECIFIERS must be #defined to 0 or 1
#endif
#ifndef NANOPRINTF_USE_LARGE_FORMAT_SPECIFIERS
#error NANOPRINTF_USE_LARGE_FORMAT_SPECIFIERS must be #defined to 0 or 1
#endif
#ifndef NANOPRINTF_USE_BINARY_FORMAT_SPECIFIERS
#error NANOPRINTF_USE_BINARY_FORMAT_SPECIFIERS must be #defined to 0 or 1
#endif
#ifndef NANOPRINTF_USE_WRITEBACK_FORMAT_SPECIFIERS
#error NANOPRINTF_USE_WRITEBACK_FORMAT_SPECIFIERS must be #defined to 0 or 1
#endif
// Ensure flags are compatible.
#if (NANOPRINTF_USE_FLOAT_FORMAT_SPECIFIERS == 1) && \
(NANOPRINTF_USE_PRECISION_FORMAT_SPECIFIERS == 0)
#error Precision format specifiers must be enabled if float support is enabled.
#endif
// intmax_t / uintmax_t require stdint from c99 / c++11
#if NANOPRINTF_USE_LARGE_FORMAT_SPECIFIERS == 1
#ifndef _MSC_VER
#ifdef __cplusplus
#if __cplusplus < 201103L
#error large format specifier support requires C++11 or later.
#endif
#else
#if __STDC_VERSION__ < 199409L
#error nanoprintf requires C99 or later.
#endif
#endif
#endif
#endif
// Figure out if we can disable warnings with pragmas.
#ifdef __clang__
#define NANOPRINTF_CLANG 1
#define NANOPRINTF_GCC_PAST_4_6 0
#else
#define NANOPRINTF_CLANG 0
#if defined(__GNUC__) && ((__GNUC__ > 4) || ((__GNUC__ == 4) && (__GNUC_MINOR__ > 6)))
#define NANOPRINTF_GCC_PAST_4_6 1
#else
#define NANOPRINTF_GCC_PAST_4_6 0
#endif
#endif
#if NANOPRINTF_CLANG || NANOPRINTF_GCC_PAST_4_6
#define NANOPRINTF_HAVE_GCC_WARNING_PRAGMAS 1
#else
#define NANOPRINTF_HAVE_GCC_WARNING_PRAGMAS 0
#endif
#if NANOPRINTF_HAVE_GCC_WARNING_PRAGMAS
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wunused-function"
#pragma GCC diagnostic ignored "-Wimplicit-fallthrough"
#ifdef __cplusplus
#pragma GCC diagnostic ignored "-Wold-style-cast"
#endif
#pragma GCC diagnostic ignored "-Wpadded"
#pragma GCC diagnostic ignored "-Wfloat-equal"
#if NANOPRINTF_CLANG
#pragma GCC diagnostic ignored "-Wc++98-compat-pedantic"
#pragma GCC diagnostic ignored "-Wcovered-switch-default"
#pragma GCC diagnostic ignored "-Wdeclaration-after-statement"
#pragma GCC diagnostic ignored "-Wzero-as-null-pointer-constant"
#ifndef __APPLE__
#pragma GCC diagnostic ignored "-Wunsafe-buffer-usage"
#endif
#elif NANOPRINTF_GCC_PAST_4_6
#pragma GCC diagnostic ignored "-Wmaybe-uninitialized"
#endif
#endif
#ifdef _MSC_VER
#pragma warning(push)
#pragma warning(disable:4619) // there is no warning number 'number'
// C4619 has to be disabled first!
#pragma warning(disable:4127) // conditional expression is constant
#pragma warning(disable:4505) // unreferenced local function has been removed
#pragma warning(disable:4514) // unreferenced inline function has been removed
#pragma warning(disable:4701) // potentially uninitialized local variable used
#pragma warning(disable:4706) // assignment within conditional expression
#pragma warning(disable:4710) // function not inlined
#pragma warning(disable:4711) // function selected for inline expansion
#pragma warning(disable:4820) // padding added after struct member
#pragma warning(disable:5039) // potentially throwing function passed to extern C function
#pragma warning(disable:5045) // compiler will insert Spectre mitigation for memory load
#pragma warning(disable:5262) // implicit switch fall-through
#pragma warning(disable:26812) // enum type is unscoped
#endif
#if defined(__clang__) || defined(__GNUC__) || defined(__GNUG__)
#define NPF_NOINLINE __attribute__((noinline))
#elif defined(_MSC_VER)
#define NPF_NOINLINE __declspec(noinline)
#else
#define NPF_NOINLINE
#endif
#if (NANOPRINTF_USE_FIELD_WIDTH_FORMAT_SPECIFIERS == 1) || \
(NANOPRINTF_USE_PRECISION_FORMAT_SPECIFIERS == 1)
enum {
NPF_FMT_SPEC_OPT_NONE,
NPF_FMT_SPEC_OPT_LITERAL,
NPF_FMT_SPEC_OPT_STAR,
};
#endif
enum {
NPF_FMT_SPEC_LEN_MOD_NONE,
NPF_FMT_SPEC_LEN_MOD_SHORT, // 'h'
NPF_FMT_SPEC_LEN_MOD_LONG_DOUBLE, // 'L'
NPF_FMT_SPEC_LEN_MOD_CHAR, // 'hh'
NPF_FMT_SPEC_LEN_MOD_LONG, // 'l'
#if NANOPRINTF_USE_LARGE_FORMAT_SPECIFIERS == 1
NPF_FMT_SPEC_LEN_MOD_LARGE_LONG_LONG, // 'll'
NPF_FMT_SPEC_LEN_MOD_LARGE_INTMAX, // 'j'
NPF_FMT_SPEC_LEN_MOD_LARGE_SIZET, // 'z'
NPF_FMT_SPEC_LEN_MOD_LARGE_PTRDIFFT, // 't'
#endif
};
enum {
NPF_FMT_SPEC_CONV_NONE,
NPF_FMT_SPEC_CONV_PERCENT, // '%'
NPF_FMT_SPEC_CONV_CHAR, // 'c'
NPF_FMT_SPEC_CONV_STRING, // 's'
NPF_FMT_SPEC_CONV_SIGNED_INT, // 'i', 'd'
#if NANOPRINTF_USE_BINARY_FORMAT_SPECIFIERS == 1
NPF_FMT_SPEC_CONV_BINARY, // 'b'
#endif
NPF_FMT_SPEC_CONV_OCTAL, // 'o'
NPF_FMT_SPEC_CONV_HEX_INT, // 'x', 'X'
NPF_FMT_SPEC_CONV_UNSIGNED_INT, // 'u'
NPF_FMT_SPEC_CONV_POINTER, // 'p'
#if NANOPRINTF_USE_WRITEBACK_FORMAT_SPECIFIERS == 1
NPF_FMT_SPEC_CONV_WRITEBACK, // 'n'
#endif
#if NANOPRINTF_USE_FLOAT_FORMAT_SPECIFIERS == 1
NPF_FMT_SPEC_CONV_FLOAT_DEC, // 'f', 'F'
NPF_FMT_SPEC_CONV_FLOAT_SCI, // 'e', 'E'
NPF_FMT_SPEC_CONV_FLOAT_SHORTEST, // 'g', 'G'
NPF_FMT_SPEC_CONV_FLOAT_HEX, // 'a', 'A'
#endif
};
typedef struct npf_format_spec {
#if NANOPRINTF_USE_FIELD_WIDTH_FORMAT_SPECIFIERS == 1
int field_width;
uint8_t field_width_opt;
char left_justified; // '-'
char leading_zero_pad; // '0'
#endif
#if NANOPRINTF_USE_PRECISION_FORMAT_SPECIFIERS == 1
int prec;
uint8_t prec_opt;
#endif
char prepend; // ' ' or '+'
char alt_form; // '#'
char case_adjust; // 'a' - 'A'
uint8_t length_modifier;
uint8_t conv_spec;
} npf_format_spec_t;
#if NANOPRINTF_USE_LARGE_FORMAT_SPECIFIERS == 0
typedef long npf_int_t;
typedef unsigned long npf_uint_t;
#else
typedef intmax_t npf_int_t;
typedef uintmax_t npf_uint_t;
#endif
typedef struct npf_bufputc_ctx {
char *dst;
size_t len;
size_t cur;
} npf_bufputc_ctx_t;
#if NANOPRINTF_USE_LARGE_FORMAT_SPECIFIERS == 1
typedef char npf_size_is_ptrdiff[(sizeof(size_t) == sizeof(ptrdiff_t)) ? 1 : -1];
typedef ptrdiff_t npf_ssize_t;
#endif
#ifdef _MSC_VER
#include <intrin.h>
#endif
static int npf_max(int x, int y) { return (x > y) ? x : y; }
static int npf_parse_format_spec(char const *format, npf_format_spec_t *out_spec) {
char const *cur = format;
#if NANOPRINTF_USE_FIELD_WIDTH_FORMAT_SPECIFIERS == 1
out_spec->left_justified = 0;
out_spec->leading_zero_pad = 0;
#endif
out_spec->case_adjust = 'a' - 'A'; // lowercase
out_spec->prepend = 0;
out_spec->alt_form = 0;
while (*++cur) { // cur points at the leading '%' character
switch (*cur) { // Optional flags
#if NANOPRINTF_USE_FIELD_WIDTH_FORMAT_SPECIFIERS == 1
case '-': out_spec->left_justified = '-'; out_spec->leading_zero_pad = 0; continue;
case '0': out_spec->leading_zero_pad = !out_spec->left_justified; continue;
#endif
case '+': out_spec->prepend = '+'; continue;
case ' ': if (out_spec->prepend == 0) { out_spec->prepend = ' '; } continue;
case '#': out_spec->alt_form = '#'; continue;
default: break;
}
break;
}
#if NANOPRINTF_USE_FIELD_WIDTH_FORMAT_SPECIFIERS == 1
out_spec->field_width_opt = NPF_FMT_SPEC_OPT_NONE;
if (*cur == '*') {
out_spec->field_width_opt = NPF_FMT_SPEC_OPT_STAR;
++cur;
} else {
out_spec->field_width = 0;
while ((*cur >= '0') && (*cur <= '9')) {
out_spec->field_width_opt = NPF_FMT_SPEC_OPT_LITERAL;
out_spec->field_width = (out_spec->field_width * 10) + (*cur++ - '0');
}
}
#endif
#if NANOPRINTF_USE_PRECISION_FORMAT_SPECIFIERS == 1
out_spec->prec = 0;
out_spec->prec_opt = NPF_FMT_SPEC_OPT_NONE;
if (*cur == '.') {
++cur;
if (*cur == '*') {
out_spec->prec_opt = NPF_FMT_SPEC_OPT_STAR;
++cur;
} else {
if (*cur == '-') {
++cur;
} else {
out_spec->prec_opt = NPF_FMT_SPEC_OPT_LITERAL;
}
while ((*cur >= '0') && (*cur <= '9')) {
out_spec->prec = (out_spec->prec * 10) + (*cur++ - '0');
}
}
}
#endif
uint_fast8_t tmp_conv = NPF_FMT_SPEC_CONV_NONE;
out_spec->length_modifier = NPF_FMT_SPEC_LEN_MOD_NONE;
switch (*cur++) { // Length modifier
case 'h':
out_spec->length_modifier = NPF_FMT_SPEC_LEN_MOD_SHORT;
if (*cur == 'h') {
out_spec->length_modifier = NPF_FMT_SPEC_LEN_MOD_CHAR;
++cur;
}
break;
case 'l':
out_spec->length_modifier = NPF_FMT_SPEC_LEN_MOD_LONG;
#if NANOPRINTF_USE_LARGE_FORMAT_SPECIFIERS == 1
if (*cur == 'l') {
out_spec->length_modifier = NPF_FMT_SPEC_LEN_MOD_LARGE_LONG_LONG;
++cur;
}
#endif
break;
#if NANOPRINTF_USE_FLOAT_FORMAT_SPECIFIERS == 1
case 'L': out_spec->length_modifier = NPF_FMT_SPEC_LEN_MOD_LONG_DOUBLE; break;
#endif
#if NANOPRINTF_USE_LARGE_FORMAT_SPECIFIERS == 1
case 'j': out_spec->length_modifier = NPF_FMT_SPEC_LEN_MOD_LARGE_INTMAX; break;
case 'z': out_spec->length_modifier = NPF_FMT_SPEC_LEN_MOD_LARGE_SIZET; break;
case 't': out_spec->length_modifier = NPF_FMT_SPEC_LEN_MOD_LARGE_PTRDIFFT; break;
#endif
default: --cur; break;
}
switch (*cur++) { // Conversion specifier
case '%': out_spec->conv_spec = NPF_FMT_SPEC_CONV_PERCENT;
#if NANOPRINTF_USE_PRECISION_FORMAT_SPECIFIERS == 1
out_spec->prec_opt = NPF_FMT_SPEC_OPT_NONE;
#endif
break;
case 'c': out_spec->conv_spec = NPF_FMT_SPEC_CONV_CHAR;
#if NANOPRINTF_USE_PRECISION_FORMAT_SPECIFIERS == 1
out_spec->prec_opt = NPF_FMT_SPEC_OPT_NONE;
#endif
break;
case 's': out_spec->conv_spec = NPF_FMT_SPEC_CONV_STRING;
#if NANOPRINTF_USE_FIELD_WIDTH_FORMAT_SPECIFIERS == 1
out_spec->leading_zero_pad = 0;
#endif
break;
case 'i':
case 'd': tmp_conv = NPF_FMT_SPEC_CONV_SIGNED_INT;
case 'o':
if (tmp_conv == NPF_FMT_SPEC_CONV_NONE) { tmp_conv = NPF_FMT_SPEC_CONV_OCTAL; }
case 'u':
if (tmp_conv == NPF_FMT_SPEC_CONV_NONE) { tmp_conv = NPF_FMT_SPEC_CONV_UNSIGNED_INT; }
case 'X':
if (tmp_conv == NPF_FMT_SPEC_CONV_NONE) { out_spec->case_adjust = 0; }
case 'x':
if (tmp_conv == NPF_FMT_SPEC_CONV_NONE) { tmp_conv = NPF_FMT_SPEC_CONV_HEX_INT; }
out_spec->conv_spec = (uint8_t)tmp_conv;
#if (NANOPRINTF_USE_FIELD_WIDTH_FORMAT_SPECIFIERS == 1) && \
(NANOPRINTF_USE_PRECISION_FORMAT_SPECIFIERS == 1)
if (out_spec->prec_opt != NPF_FMT_SPEC_OPT_NONE) { out_spec->leading_zero_pad = 0; }
#endif
break;
#if NANOPRINTF_USE_FLOAT_FORMAT_SPECIFIERS == 1
case 'F': out_spec->case_adjust = 0;
case 'f':
out_spec->conv_spec = NPF_FMT_SPEC_CONV_FLOAT_DEC;
if (out_spec->prec_opt == NPF_FMT_SPEC_OPT_NONE) { out_spec->prec = 6; }
break;
case 'E': out_spec->case_adjust = 0;
case 'e':
out_spec->conv_spec = NPF_FMT_SPEC_CONV_FLOAT_SCI;
if (out_spec->prec_opt == NPF_FMT_SPEC_OPT_NONE) { out_spec->prec = 6; }
break;
case 'G': out_spec->case_adjust = 0;
case 'g':
out_spec->conv_spec = NPF_FMT_SPEC_CONV_FLOAT_SHORTEST;
if (out_spec->prec_opt == NPF_FMT_SPEC_OPT_NONE) { out_spec->prec = 6; }
break;
case 'A': out_spec->case_adjust = 0;
case 'a':
out_spec->conv_spec = NPF_FMT_SPEC_CONV_FLOAT_HEX;
if (out_spec->prec_opt == NPF_FMT_SPEC_OPT_NONE) { out_spec->prec = 6; }
break;
#endif
#if NANOPRINTF_USE_WRITEBACK_FORMAT_SPECIFIERS == 1
case 'n':
// todo: reject string if flags or width or precision exist
out_spec->conv_spec = NPF_FMT_SPEC_CONV_WRITEBACK;
#if NANOPRINTF_USE_PRECISION_FORMAT_SPECIFIERS == 1
out_spec->prec_opt = NPF_FMT_SPEC_OPT_NONE;
#endif
break;
#endif
case 'p':
out_spec->conv_spec = NPF_FMT_SPEC_CONV_POINTER;
#if NANOPRINTF_USE_PRECISION_FORMAT_SPECIFIERS == 1
out_spec->prec_opt = NPF_FMT_SPEC_OPT_NONE;
#endif
break;
#if NANOPRINTF_USE_BINARY_FORMAT_SPECIFIERS == 1
case 'B':
out_spec->case_adjust = 0;
case 'b':
out_spec->conv_spec = NPF_FMT_SPEC_CONV_BINARY;
break;
#endif
default: return 0;
}
return (int)(cur - format);
}
static NPF_NOINLINE int npf_utoa_rev(
npf_uint_t val, char *buf, uint_fast8_t base, char case_adj) {
uint_fast8_t n = 0;
do {
int_fast8_t const d = (int_fast8_t)(val % base);
*buf++ = (char)(((d < 10) ? '0' : ('A' - 10 + case_adj)) + d);
++n;
val /= base;
} while (val);
return (int)n;
}
#if NANOPRINTF_USE_FLOAT_FORMAT_SPECIFIERS == 1
#include <float.h>
#if (DBL_MANT_DIG <= 11) && (DBL_MAX_EXP <= 16)
typedef uint_fast16_t npf_double_bin_t;
typedef int_fast8_t npf_ftoa_exp_t;
#elif (DBL_MANT_DIG <= 24) && (DBL_MAX_EXP <= 128)
typedef uint_fast32_t npf_double_bin_t;
typedef int_fast8_t npf_ftoa_exp_t;
#elif (DBL_MANT_DIG <= 53) && (DBL_MAX_EXP <= 1024)
typedef uint_fast64_t npf_double_bin_t;
typedef int_fast16_t npf_ftoa_exp_t;
#else
#error Unsupported width of the double type.
#endif
// The floating point conversion code works with an unsigned integer type of any size.
#ifndef NANOPRINTF_CONVERSION_FLOAT_TYPE
#define NANOPRINTF_CONVERSION_FLOAT_TYPE unsigned int
#endif
typedef NANOPRINTF_CONVERSION_FLOAT_TYPE npf_ftoa_man_t;
#if (NANOPRINTF_CONVERSION_BUFFER_SIZE <= UINT_FAST8_MAX) && (UINT_FAST8_MAX <= INT_MAX)
typedef uint_fast8_t npf_ftoa_dec_t;
#else
typedef int npf_ftoa_dec_t;
#endif
enum {
NPF_DOUBLE_EXP_MASK = DBL_MAX_EXP * 2 - 1,
NPF_DOUBLE_EXP_BIAS = DBL_MAX_EXP - 1,
NPF_DOUBLE_MAN_BITS = DBL_MANT_DIG - 1,
NPF_DOUBLE_BIN_BITS = sizeof(npf_double_bin_t) * CHAR_BIT,
NPF_FTOA_MAN_BITS = sizeof(npf_ftoa_man_t) * CHAR_BIT,
NPF_FTOA_SHIFT_BITS =
((NPF_FTOA_MAN_BITS < DBL_MANT_DIG) ? NPF_FTOA_MAN_BITS : DBL_MANT_DIG) - 1
};
/* Generally, floating-point conversion implementations use
grisu2 (https://bit.ly/2JgMggX) and ryu (https://bit.ly/2RLXSg0) algorithms,
which are mathematically exact and fast, but require large lookup tables.
This implementation was inspired by Wojciech Muła's (zdjęcia@garnek.pl)
algorithm (http://0x80.pl/notesen/2015-12-29-float-to-string.html) and
extended further by adding dynamic scaling and configurable integer width by
Oskars Rubenis (https://github.com/Okarss). */
static int npf_ftoa_rev(char *buf, npf_format_spec_t const *spec, double f) {
char const *ret = NULL;
npf_double_bin_t bin; { // Union-cast is UB pre-C11, compiler optimizes byte-copy loop.
char const *src = (char const *)&f;
char *dst = (char *)&bin;
for (uint_fast8_t i = 0; i < sizeof(f); ++i) { dst[i] = src[i]; }
}
// Unsigned -> signed int casting is IB and can raise a signal but generally doesn't.
npf_ftoa_exp_t exp =
(npf_ftoa_exp_t)((npf_ftoa_exp_t)(bin >> NPF_DOUBLE_MAN_BITS) & NPF_DOUBLE_EXP_MASK);
bin &= ((npf_double_bin_t)0x1 << NPF_DOUBLE_MAN_BITS) - 1;
if (exp == (npf_ftoa_exp_t)NPF_DOUBLE_EXP_MASK) { // special value
ret = (bin) ? "NAN" : "FNI";
goto exit;
}
if (spec->prec > (NANOPRINTF_CONVERSION_BUFFER_SIZE - 2)) { goto exit; }
if (exp) { // normal number
bin |= (npf_double_bin_t)0x1 << NPF_DOUBLE_MAN_BITS;
} else { // subnormal number
++exp;
}
exp = (npf_ftoa_exp_t)(exp - NPF_DOUBLE_EXP_BIAS);
uint_fast8_t carry; carry = 0;
npf_ftoa_dec_t end, dec; dec = (npf_ftoa_dec_t)spec->prec;
if (dec || spec->alt_form) {
buf[dec++] = '.';
}
{ // Integer part
npf_ftoa_man_t man_i;
if (exp >= 0) {
int_fast8_t shift_i =
(int_fast8_t)((exp > NPF_FTOA_SHIFT_BITS) ? (int)NPF_FTOA_SHIFT_BITS : exp);
npf_ftoa_exp_t exp_i = (npf_ftoa_exp_t)(exp - shift_i);
shift_i = (int_fast8_t)(NPF_DOUBLE_MAN_BITS - shift_i);
man_i = (npf_ftoa_man_t)(bin >> shift_i);
if (exp_i) {
if (shift_i) {
carry = (bin >> (shift_i - 1)) & 0x1;
}
exp = NPF_DOUBLE_MAN_BITS; // invalidate the fraction part
}
// Scale the exponent from base-2 to base-10.
for (; exp_i; --exp_i) {
if (!(man_i & ((npf_ftoa_man_t)0x1 << (NPF_FTOA_MAN_BITS - 1)))) {
man_i = (npf_ftoa_man_t)(man_i << 1);
man_i = (npf_ftoa_man_t)(man_i | carry); carry = 0;
} else {
if (dec >= NANOPRINTF_CONVERSION_BUFFER_SIZE) { goto exit; }
buf[dec++] = '0';
carry = (((uint_fast8_t)(man_i % 5) + carry) > 2);
man_i /= 5;
}
}
} else {
man_i = 0;
}
end = dec;
do { // Print the integer
if (end >= NANOPRINTF_CONVERSION_BUFFER_SIZE) { goto exit; }
buf[end++] = (char)('0' + (char)(man_i % 10));
man_i /= 10;
} while (man_i);
}
{ // Fraction part
npf_ftoa_man_t man_f;
npf_ftoa_dec_t dec_f = (npf_ftoa_dec_t)spec->prec;
if (exp < NPF_DOUBLE_MAN_BITS) {
int_fast8_t shift_f = (int_fast8_t)((exp < 0) ? -1 : exp);
npf_ftoa_exp_t exp_f = (npf_ftoa_exp_t)(exp - shift_f);
npf_double_bin_t bin_f =
bin << ((NPF_DOUBLE_BIN_BITS - NPF_DOUBLE_MAN_BITS) + shift_f);
// This if-else statement can be completely optimized at compile time.
if (NPF_DOUBLE_BIN_BITS > NPF_FTOA_MAN_BITS) {
man_f = (npf_ftoa_man_t)(bin_f >> ((unsigned)(NPF_DOUBLE_BIN_BITS -
NPF_FTOA_MAN_BITS) %
NPF_DOUBLE_BIN_BITS));
carry = (uint_fast8_t)((bin_f >> ((unsigned)(NPF_DOUBLE_BIN_BITS -
NPF_FTOA_MAN_BITS - 1) %
NPF_DOUBLE_BIN_BITS)) & 0x1);
} else {
man_f = (npf_ftoa_man_t)((npf_ftoa_man_t)bin_f
<< ((unsigned)(NPF_FTOA_MAN_BITS -
NPF_DOUBLE_BIN_BITS) % NPF_FTOA_MAN_BITS));
carry = 0;
}
// Scale the exponent from base-2 to base-10 and prepare the first digit.
for (uint_fast8_t digit = 0; dec_f && (exp_f < 4); ++exp_f) {
if ((man_f > ((npf_ftoa_man_t)-4 / 5)) || digit) {
carry = (uint_fast8_t)(man_f & 0x1);
man_f = (npf_ftoa_man_t)(man_f >> 1);
} else {
man_f = (npf_ftoa_man_t)(man_f * 5);
if (carry) { man_f = (npf_ftoa_man_t)(man_f + 3); carry = 0; }
if (exp_f < 0) {
buf[--dec_f] = '0';
} else {
++digit;
}
}
}
man_f = (npf_ftoa_man_t)(man_f + carry);
carry = (exp_f >= 0);
dec = 0;
} else {
man_f = 0;
}
if (dec_f) {
// Print the fraction
for (;;) {
buf[--dec_f] = (char)('0' + (char)(man_f >> (NPF_FTOA_MAN_BITS - 4)));
man_f = (npf_ftoa_man_t)(man_f & ~((npf_ftoa_man_t)0xF << (NPF_FTOA_MAN_BITS - 4)));
if (!dec_f) { break; }
man_f = (npf_ftoa_man_t)(man_f * 10);
}
man_f = (npf_ftoa_man_t)(man_f << 4);
}
if (exp < NPF_DOUBLE_MAN_BITS) {
carry &= (uint_fast8_t)(man_f >> (NPF_FTOA_MAN_BITS - 1));
}
}
// Round the number
for (; carry; ++dec) {
if (dec >= NANOPRINTF_CONVERSION_BUFFER_SIZE) { goto exit; }
if (dec >= end) { buf[end++] = '0'; }
if (buf[dec] == '.') { continue; }
carry = (buf[dec] == '9');
buf[dec] = (char)(carry ? '0' : (buf[dec] + 1));
}
return (int)end;
exit:
if (!ret) { ret = "RRE"; }
uint_fast8_t i;
for (i = 0; ret[i]; ++i) { buf[i] = (char)(ret[i] + spec->case_adjust); }
return (int)i;
}
#endif // NANOPRINTF_USE_FLOAT_FORMAT_SPECIFIERS
#if NANOPRINTF_USE_BINARY_FORMAT_SPECIFIERS == 1
static int npf_bin_len(npf_uint_t u) {
// Return the length of the binary string format of 'u', preferring intrinsics.
if (!u) { return 1; }
#ifdef _MSC_VER // Win64, use _BSR64 for everything. If x86, use _BSR when non-large.
#ifdef _M_X64
#define NPF_HAVE_BUILTIN_CLZ
#define NPF_CLZ _BitScanReverse64
#elif NANOPRINTF_USE_LARGE_FORMAT_SPECIFIERS == 0
#define NPF_HAVE_BUILTIN_CLZ
#define NPF_CLZ _BitScanReverse
#endif
#ifdef NPF_HAVE_BUILTIN_CLZ
unsigned long idx;
NPF_CLZ(&idx, u);
return (int)(idx + 1);
#endif
#elif NANOPRINTF_CLANG || NANOPRINTF_GCC_PAST_4_6
#define NPF_HAVE_BUILTIN_CLZ
#if NANOPRINTF_USE_LARGE_FORMAT_SPECIFIERS == 1
#define NPF_CLZ(X) ((sizeof(long long) * CHAR_BIT) - (size_t)__builtin_clzll(X))
#else
#define NPF_CLZ(X) ((sizeof(long) * CHAR_BIT) - (size_t)__builtin_clzl(X))
#endif
return (int)NPF_CLZ(u);
#endif
#ifndef NPF_HAVE_BUILTIN_CLZ
int n;
for (n = 0; u; ++n, u >>= 1); // slow but small software fallback
return n;
#else
#undef NPF_HAVE_BUILTIN_CLZ
#undef NPF_CLZ
#endif
}
#endif
static void npf_bufputc(int c, void *ctx) {
npf_bufputc_ctx_t *bpc = (npf_bufputc_ctx_t *)ctx;
if (bpc->cur < bpc->len) { bpc->dst[bpc->cur++] = (char)c; }
}
static void npf_bufputc_nop(int c, void *ctx) { (void)c; (void)ctx; }
typedef struct npf_cnt_putc_ctx {
npf_putc pc;
void *ctx;
int n;
} npf_cnt_putc_ctx_t;
static void npf_putc_cnt(int c, void *ctx) {
npf_cnt_putc_ctx_t *pc_cnt = (npf_cnt_putc_ctx_t *)ctx;
++pc_cnt->n;
pc_cnt->pc(c, pc_cnt->ctx); // sibling-call optimization
}
#define NPF_PUTC(VAL) do { npf_putc_cnt((int)(VAL), &pc_cnt); } while (0)
#define NPF_EXTRACT(MOD, CAST_TO, EXTRACT_AS) \
case NPF_FMT_SPEC_LEN_MOD_##MOD: val = (CAST_TO)va_arg(args, EXTRACT_AS); break
#define NPF_WRITEBACK(MOD, TYPE) \
case NPF_FMT_SPEC_LEN_MOD_##MOD: *(va_arg(args, TYPE *)) = (TYPE)pc_cnt.n; break
int npf_vpprintf(npf_putc pc, void *pc_ctx, char const *format, va_list args) {
npf_format_spec_t fs;
char const *cur = format;
npf_cnt_putc_ctx_t pc_cnt;
pc_cnt.pc = pc;
pc_cnt.ctx = pc_ctx;
pc_cnt.n = 0;
while (*cur) {
int const fs_len = (*cur != '%') ? 0 : npf_parse_format_spec(cur, &fs);
if (!fs_len) { NPF_PUTC(*cur++); continue; }
cur += fs_len;
// Extract star-args immediately
#if NANOPRINTF_USE_FIELD_WIDTH_FORMAT_SPECIFIERS == 1
if (fs.field_width_opt == NPF_FMT_SPEC_OPT_STAR) {
fs.field_width = va_arg(args, int);
if (fs.field_width < 0) {
fs.field_width = -fs.field_width;
fs.left_justified = 1;
}
}
#endif
#if NANOPRINTF_USE_PRECISION_FORMAT_SPECIFIERS == 1
if (fs.prec_opt == NPF_FMT_SPEC_OPT_STAR) {
fs.prec = va_arg(args, int);
if (fs.prec < 0) { fs.prec_opt = NPF_FMT_SPEC_OPT_NONE; }
}
#endif
union { char cbuf_mem[NANOPRINTF_CONVERSION_BUFFER_SIZE]; npf_uint_t binval; } u;
char *cbuf = u.cbuf_mem, sign_c = 0;
int cbuf_len = 0, need_0x = 0;
#if NANOPRINTF_USE_FIELD_WIDTH_FORMAT_SPECIFIERS == 1
int field_pad = 0;
char pad_c = 0;
#endif
#if NANOPRINTF_USE_PRECISION_FORMAT_SPECIFIERS == 1
int prec_pad = 0;
#if NANOPRINTF_USE_FIELD_WIDTH_FORMAT_SPECIFIERS == 1
int zero = 0;
#endif
#endif
// Extract and convert the argument to string, point cbuf at the text.
switch (fs.conv_spec) {
case NPF_FMT_SPEC_CONV_PERCENT:
*cbuf = '%';
cbuf_len = 1;
break;
case NPF_FMT_SPEC_CONV_CHAR:
*cbuf = (char)va_arg(args, int);
cbuf_len = 1;
break;
case NPF_FMT_SPEC_CONV_STRING: {
cbuf = va_arg(args, char *);
#if NANOPRINTF_USE_PRECISION_FORMAT_SPECIFIERS == 1
for (char const *s = cbuf;
((fs.prec_opt == NPF_FMT_SPEC_OPT_NONE) || (cbuf_len < fs.prec)) && *s;
++s, ++cbuf_len);
#else
for (char const *s = cbuf; *s; ++s, ++cbuf_len); // strlen
#endif
} break;
case NPF_FMT_SPEC_CONV_SIGNED_INT: {
npf_int_t val = 0;
switch (fs.length_modifier) {
NPF_EXTRACT(NONE, int, int);
NPF_EXTRACT(SHORT, short, int);
NPF_EXTRACT(LONG_DOUBLE, int, int);
NPF_EXTRACT(CHAR, char, int);
NPF_EXTRACT(LONG, long, long);
#if NANOPRINTF_USE_LARGE_FORMAT_SPECIFIERS == 1
NPF_EXTRACT(LARGE_LONG_LONG, long long, long long);
NPF_EXTRACT(LARGE_INTMAX, intmax_t, intmax_t);
NPF_EXTRACT(LARGE_SIZET, npf_ssize_t, npf_ssize_t);
NPF_EXTRACT(LARGE_PTRDIFFT, ptrdiff_t, ptrdiff_t);
#endif
default: break;
}
sign_c = (val < 0) ? '-' : fs.prepend;
#if NANOPRINTF_USE_PRECISION_FORMAT_SPECIFIERS == 1
#if NANOPRINTF_USE_FIELD_WIDTH_FORMAT_SPECIFIERS == 1
zero = !val;
#endif
// special case, if prec and value are 0, skip
if (!val && (fs.prec_opt != NPF_FMT_SPEC_OPT_NONE) && !fs.prec) {
cbuf_len = 0;
} else
#endif
{
npf_uint_t uval = (npf_uint_t)val;
if (val < 0) { uval = 0 - uval; }
cbuf_len = npf_utoa_rev(uval, cbuf, 10, fs.case_adjust);
}
} break;
#if NANOPRINTF_USE_BINARY_FORMAT_SPECIFIERS == 1
case NPF_FMT_SPEC_CONV_BINARY:
#endif
case NPF_FMT_SPEC_CONV_OCTAL:
case NPF_FMT_SPEC_CONV_HEX_INT:
case NPF_FMT_SPEC_CONV_UNSIGNED_INT: {
npf_uint_t val = 0;
switch (fs.length_modifier) {
NPF_EXTRACT(NONE, unsigned, unsigned);
NPF_EXTRACT(SHORT, unsigned short, unsigned);
NPF_EXTRACT(LONG_DOUBLE, unsigned, unsigned);
NPF_EXTRACT(CHAR, unsigned char, unsigned);
NPF_EXTRACT(LONG, unsigned long, unsigned long);
#if NANOPRINTF_USE_LARGE_FORMAT_SPECIFIERS == 1
NPF_EXTRACT(LARGE_LONG_LONG, unsigned long long, unsigned long long);
NPF_EXTRACT(LARGE_INTMAX, uintmax_t, uintmax_t);
NPF_EXTRACT(LARGE_SIZET, size_t, size_t);
NPF_EXTRACT(LARGE_PTRDIFFT, size_t, size_t);
#endif
default: break;
}
#if NANOPRINTF_USE_PRECISION_FORMAT_SPECIFIERS == 1
#if NANOPRINTF_USE_FIELD_WIDTH_FORMAT_SPECIFIERS == 1
zero = !val;
#endif
if (!val && (fs.prec_opt != NPF_FMT_SPEC_OPT_NONE) && !fs.prec) {
// Zero value and explicitly-requested zero precision means "print nothing".
if ((fs.conv_spec == NPF_FMT_SPEC_CONV_OCTAL) && fs.alt_form) {
fs.prec = 1; // octal special case, print a single '0'
}
} else
#endif
#if NANOPRINTF_USE_BINARY_FORMAT_SPECIFIERS == 1
if (fs.conv_spec == NPF_FMT_SPEC_CONV_BINARY) {
cbuf_len = npf_bin_len(val); u.binval = val;
} else
#endif
{
uint_fast8_t const base = (fs.conv_spec == NPF_FMT_SPEC_CONV_OCTAL) ?
8u : ((fs.conv_spec == NPF_FMT_SPEC_CONV_HEX_INT) ? 16u : 10u);
cbuf_len = npf_utoa_rev(val, cbuf, base, fs.case_adjust);
}
if (val && fs.alt_form && (fs.conv_spec == NPF_FMT_SPEC_CONV_OCTAL)) {
cbuf[cbuf_len++] = '0'; // OK to add leading octal '0' immediately.
}
if (val && fs.alt_form) { // 0x or 0b but can't write it yet.
if (fs.conv_spec == NPF_FMT_SPEC_CONV_HEX_INT) { need_0x = 'X'; }
#if NANOPRINTF_USE_BINARY_FORMAT_SPECIFIERS == 1
else if (fs.conv_spec == NPF_FMT_SPEC_CONV_BINARY) { need_0x = 'B'; }
#endif
if (need_0x) { need_0x += fs.case_adjust; }
}
} break;
case NPF_FMT_SPEC_CONV_POINTER: {
cbuf_len =
npf_utoa_rev((npf_uint_t)(uintptr_t)va_arg(args, void *), cbuf, 16, 'a' - 'A');
need_0x = 'x';
} break;
#if NANOPRINTF_USE_WRITEBACK_FORMAT_SPECIFIERS == 1
case NPF_FMT_SPEC_CONV_WRITEBACK:
switch (fs.length_modifier) {
NPF_WRITEBACK(NONE, int);
NPF_WRITEBACK(SHORT, short);
NPF_WRITEBACK(LONG, long);
NPF_WRITEBACK(LONG_DOUBLE, double);
NPF_WRITEBACK(CHAR, signed char);
#if NANOPRINTF_USE_LARGE_FORMAT_SPECIFIERS == 1
NPF_WRITEBACK(LARGE_LONG_LONG, long long);
NPF_WRITEBACK(LARGE_INTMAX, intmax_t);
NPF_WRITEBACK(LARGE_SIZET, size_t);
NPF_WRITEBACK(LARGE_PTRDIFFT, ptrdiff_t);
#endif
default: break;
} break;
#endif
#if NANOPRINTF_USE_FLOAT_FORMAT_SPECIFIERS == 1
case NPF_FMT_SPEC_CONV_FLOAT_DEC:
case NPF_FMT_SPEC_CONV_FLOAT_SCI:
case NPF_FMT_SPEC_CONV_FLOAT_SHORTEST:
case NPF_FMT_SPEC_CONV_FLOAT_HEX: {
double val;
if (fs.length_modifier == NPF_FMT_SPEC_LEN_MOD_LONG_DOUBLE) {
val = (double)va_arg(args, long double);
} else {
val = va_arg(args, double);
}
sign_c = (val < 0.) ? '-' : fs.prepend;
#if NANOPRINTF_USE_FIELD_WIDTH_FORMAT_SPECIFIERS == 1
zero = (val == 0.);
#endif
cbuf_len = npf_ftoa_rev(cbuf, &fs, val);
} break;
#endif
default: break;
}
#if NANOPRINTF_USE_FIELD_WIDTH_FORMAT_SPECIFIERS == 1
// Compute the field width pad character
if (fs.field_width_opt != NPF_FMT_SPEC_OPT_NONE) {
if (fs.leading_zero_pad) { // '0' flag is only legal with numeric types
if ((fs.conv_spec != NPF_FMT_SPEC_CONV_STRING) &&
(fs.conv_spec != NPF_FMT_SPEC_CONV_CHAR) &&
(fs.conv_spec != NPF_FMT_SPEC_CONV_PERCENT)) {
#if NANOPRINTF_USE_PRECISION_FORMAT_SPECIFIERS == 1
if ((fs.prec_opt != NPF_FMT_SPEC_OPT_NONE) && !fs.prec && zero) {
pad_c = ' ';
} else
#endif
{ pad_c = '0'; }
}
} else { pad_c = ' '; }
}
#endif
// Compute the number of bytes to truncate or '0'-pad.
#if NANOPRINTF_USE_PRECISION_FORMAT_SPECIFIERS == 1
if (fs.conv_spec != NPF_FMT_SPEC_CONV_STRING) {
#if NANOPRINTF_USE_FLOAT_FORMAT_SPECIFIERS == 1
// float precision is after the decimal point
if (fs.conv_spec != NPF_FMT_SPEC_CONV_FLOAT_DEC)
#endif
{ prec_pad = npf_max(0, fs.prec - cbuf_len); }
}
#endif
#if NANOPRINTF_USE_FIELD_WIDTH_FORMAT_SPECIFIERS == 1
// Given the full converted length, how many pad bytes?
field_pad = fs.field_width - cbuf_len - !!sign_c;
if (need_0x) { field_pad -= 2; }
#if NANOPRINTF_USE_PRECISION_FORMAT_SPECIFIERS == 1
field_pad -= prec_pad;
#endif
field_pad = npf_max(0, field_pad);
// Apply right-justified field width if requested
if (!fs.left_justified && pad_c) { // If leading zeros pad, sign goes first.
if (pad_c == '0') {
if (sign_c) { NPF_PUTC(sign_c); sign_c = 0; }
// Pad byte is '0', write '0x' before '0' pad chars.
if (need_0x) { NPF_PUTC('0'); NPF_PUTC(need_0x); }