/** * @author (c) Eyal Rozenberg * 2021, Haifa, Palestine/Israel * @author (c) Marco Paland (info@paland.com) * 2014-2019, PALANDesign Hannover, Germany * * @note Others have made smaller contributions to this file: see the * contributors page at https://github.com/eyalroz/printf/graphs/contributors * or ask one of the authors. * * @brief Small stand-alone implementation of the printf family of functions * (`(v)printf`, `(v)s(n)printf` etc., geared towards use on embedded systems with * a very limited resources. * * @note the implementations are thread-safe; re-entrant; use no functions from * the standard library; and do not dynamically allocate any memory. * * @license The MIT License (MIT) * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN * THE SOFTWARE. */ #include #include #include #include // 'ntoa' conversion buffer size, this must be big enough to hold one converted // numeric number including padded zeros (dynamically created on stack) #ifndef PRINTF_INTEGER_BUFFER_SIZE #define PRINTF_INTEGER_BUFFER_SIZE 32 #endif // 'ftoa' conversion buffer size, this must be big enough to hold one converted // float number including padded zeros (dynamically created on stack) #ifndef PRINTF_FTOA_BUFFER_SIZE #define PRINTF_FTOA_BUFFER_SIZE 32 #endif // Support for the decimal notation floating point conversion specifiers (%f, %F) #ifndef CONFIG_LIBC_FLOAT #define CONFIG_LIBC_FLOAT 1 #endif // Support for the exponential notatin floating point conversion specifiers (%e, %g, %E, %G) #ifndef CONFIG_LIBC_FLOAT_EX #define CONFIG_LIBC_FLOAT_EX 0 #endif // Default precision for the floating point conversion specifiers (the C standard sets this at 6) #ifndef PRINTF_DEFAULT_FLOAT_PRECISION #define PRINTF_DEFAULT_FLOAT_PRECISION 6 #endif // According to the C languages standard, printf() and related functions must be able to print any // integral number in floating-point notation, regardless of length, when using the %f specifier - // possibly hundreds of characters, potentially overflowing your buffers. In this implementation, // all values beyond this threshold are switched to exponential notation. #ifndef PRINTF_MAX_INTEGRAL_DIGITS_FOR_DECIMAL #define PRINTF_MAX_INTEGRAL_DIGITS_FOR_DECIMAL 9 #endif // Support for the long long integral types (with the ll, z and t length modifiers for specifiers // %d,%i,%o,%x,%X,%u, and with the %p specifier). Note: 'L' (long double) is not supported. #ifndef CONFIG_LIBC_LONG_LONG #define CONFIG_LIBC_LONG_LONG 1 #endif #ifndef PRINTF_SUPPORT_LENGTH_FILED #define PRINTF_SUPPORT_LENGTH_FILED 1 #endif #ifndef PRINTF_SUPPORT_CHAR #define PRINTF_SUPPORT_CHAR 1 #endif #ifndef PRINTF_SUPPORT_ADDR #define PRINTF_SUPPORT_ADDR 1 #endif #if CONFIG_LIBC_LONG_LONG typedef unsigned long long printf_unsigned_value_t; typedef long long printf_signed_value_t; #else typedef unsigned long printf_unsigned_value_t; typedef long printf_signed_value_t; #endif #define PRINTF_PREFER_DECIMAL false #define PRINTF_PREFER_EXPONENTIAL true /////////////////////////////////////////////////////////////////////////////// // The following will convert the number-of-digits into an exponential-notation literal #define PRINTF_CONCATENATE(s1, s2) s1##s2 #define PRINTF_EXPAND_THEN_CONCATENATE(s1, s2) PRINTF_CONCATENATE(s1, s2) #define PRINTF_FLOAT_NOTATION_THRESHOLD PRINTF_EXPAND_THEN_CONCATENATE(1e,PRINTF_MAX_INTEGRAL_DIGITS_FOR_DECIMAL) // internal flag definitions #define FLAGS_ZEROPAD (1U << 0U) #define FLAGS_LEFT (1U << 1U) #define FLAGS_PLUS (1U << 2U) #define FLAGS_SPACE (1U << 3U) #define FLAGS_HASH (1U << 4U) #define FLAGS_UPPERCASE (1U << 5U) #define FLAGS_CHAR (1U << 6U) #define FLAGS_SHORT (1U << 7U) #define FLAGS_LONG (1U << 8U) #define FLAGS_LONG_LONG (1U << 9U) #define FLAGS_PRECISION (1U << 10U) #define FLAGS_ADAPT_EXP (1U << 11U) #define FLAGS_POINTER (1U << 12U) // Note: Similar, but not identical, effect as FLAGS_HASH #define BASE_BINARY 2 #define BASE_OCTAL 8 #define BASE_DECIMAL 10 #define BASE_HEX 16 typedef uint8_t numeric_base_t; #if (CONFIG_LIBC_FLOAT || CONFIG_LIBC_FLOAT_EX) #include #if FLT_RADIX != 2 #error "Non-binary-radix floating-point types are unsupported." #endif #if DBL_MANT_DIG == 24 #define DOUBLE_SIZE_IN_BITS 32 typedef uint32_t double_uint_t; #define DOUBLE_EXPONENT_MASK 0xFFU #define DOUBLE_BASE_EXPONENT 127 #elif DBL_MANT_DIG == 53 #define DOUBLE_SIZE_IN_BITS 64 typedef uint64_t double_uint_t; #define DOUBLE_EXPONENT_MASK 0x7FFU #define DOUBLE_BASE_EXPONENT 1023 #else #error "Unsupported double type configuration" #endif #define DOUBLE_STORED_MANTISSA_BITS (DBL_MANT_DIG - 1) typedef union { double_uint_t U; double F; } double_with_bit_access; // This is unnecessary in C99, since compound initializers can be used, // but: 1. Some compilers are finicky about this; 2. Some people may want to convert this to C89; // 3. If you try to use it as C++, only C++20 supports compound literals static inline double_with_bit_access get_bit_access(double x) { double_with_bit_access dwba; dwba.F = x; return dwba; } static inline int get_sign(double x) { // The sign is stored in the highest bit return get_bit_access(x).U >> (DOUBLE_SIZE_IN_BITS - 1); } static inline int get_exp2(double_with_bit_access x) { // The exponent in an IEEE-754 floating-point number occupies a contiguous // sequence of bits (e.g. 52..62 for 64-bit doubles), but with a non-trivial representation: An // unsigned offset from some negative value (with the extremal offset values reserved for // special use). return (int)((x.U >> DOUBLE_STORED_MANTISSA_BITS ) & DOUBLE_EXPONENT_MASK) - DOUBLE_BASE_EXPONENT; } #define PRINTF_ABS(_x) ( (_x) > 0 ? (_x) : -(_x) ) #endif // (CONFIG_LIBC_FLOAT || CONFIG_LIBC_FLOAT_EX) // Note in particular the behavior here on LONG_MIN or LLONG_MIN; it is valid // and well-defined, but if you're not careful you can easily trigger undefined // behavior with -LONG_MIN or -LLONG_MIN #define ABS_FOR_PRINTING(_x) ((printf_unsigned_value_t) ( (_x) > 0 ? (_x) : -((printf_signed_value_t)_x) )) // output function type typedef void (*out_fct_type)(char character, void* buffer, size_t idx, size_t maxlen); // wrapper (used as buffer) for output function type typedef struct { void (*fct)(char character, void* arg); void* arg; } out_function_wrapper_type; // internal buffer output static inline void out_buffer(char character, void* buffer, size_t idx, size_t maxlen) { if (idx < maxlen) { ((char*)buffer)[idx] = character; } } // internal null output static inline void out_discard(char character, void* buffer, size_t idx, size_t maxlen) { (void)character; (void)buffer; (void)idx; (void)maxlen; } // internal secure strlen // @return The length of the string (excluding the terminating 0) limited by 'maxsize' static inline unsigned int strnlen_s_(const char* str, size_t maxsize) { const char* s; for (s = str; *s && maxsize--; ++s); return (unsigned int)(s - str); } // internal test if char is a digit (0-9) // @return true if char is a digit static inline bool is_digit_(char ch) { return (ch >= '0') && (ch <= '9'); } // internal ASCII string to unsigned int conversion static unsigned int atoi_(const char** str) { unsigned int i = 0U; while (is_digit_(**str)) { i = i * 10U + (unsigned int)(*((*str)++) - '0'); } return i; } // output the specified string in reverse, taking care of any zero-padding static size_t out_rev_(out_fct_type out, char* buffer, size_t idx, size_t maxlen, const char* buf, size_t len, unsigned int width, unsigned int flags) { const size_t start_idx = idx; // pad spaces up to given width if (!(flags & FLAGS_LEFT) && !(flags & FLAGS_ZEROPAD)) { for (size_t i = len; i < width; i++) { out(' ', buffer, idx++, maxlen); } } // reverse string while (len) { out(buf[--len], buffer, idx++, maxlen); } // append pad spaces up to given width if (flags & FLAGS_LEFT) { while (idx - start_idx < width) { out(' ', buffer, idx++, maxlen); } } return idx; } // Invoked by print_integer after the actual number has been printed, performing necessary // work on the number's prefix (as the number is initially printed in reverse order) static size_t print_integer_finalization(out_fct_type out, char* buffer, size_t idx, size_t maxlen, char* buf, size_t len, bool negative, numeric_base_t base, unsigned int precision, unsigned int width, unsigned int flags) { size_t unpadded_len = len; // pad with leading zeros { if (!(flags & FLAGS_LEFT)) { if (width && (flags & FLAGS_ZEROPAD) && (negative || (flags & (FLAGS_PLUS | FLAGS_SPACE)))) { width--; } while ((flags & FLAGS_ZEROPAD) && (len < width) && (len < PRINTF_INTEGER_BUFFER_SIZE)) { buf[len++] = '0'; } } while ((len < precision) && (len < PRINTF_INTEGER_BUFFER_SIZE)) { buf[len++] = '0'; } if (base == BASE_OCTAL && (len > unpadded_len)) { // Since we've written some zeros, we've satisfied the alternative format leading space requirement flags &= ~FLAGS_HASH; } } // handle hash if (flags & (FLAGS_HASH | FLAGS_POINTER)) { if (!(flags & FLAGS_PRECISION) && len && ((len == precision) || (len == width))) { // Let's take back some padding digits to fit in what will eventually // be the format-specific prefix if (unpadded_len < len) { len--; } if (len && (base == BASE_HEX)) { if (unpadded_len < len) { len--; } } } if ((base == BASE_HEX) && !(flags & FLAGS_UPPERCASE) && (len < PRINTF_INTEGER_BUFFER_SIZE)) { buf[len++] = 'x'; } else if ((base == BASE_HEX) && (flags & FLAGS_UPPERCASE) && (len < PRINTF_INTEGER_BUFFER_SIZE)) { buf[len++] = 'X'; } else if ((base == BASE_BINARY) && (len < PRINTF_INTEGER_BUFFER_SIZE)) { buf[len++] = 'b'; } if (len < PRINTF_INTEGER_BUFFER_SIZE) { buf[len++] = '0'; } } if (len < PRINTF_INTEGER_BUFFER_SIZE) { if (negative) { buf[len++] = '-'; } else if (flags & FLAGS_PLUS) { buf[len++] = '+'; // ignore the space if the '+' exists } else if (flags & FLAGS_SPACE) { buf[len++] = ' '; } } return out_rev_(out, buffer, idx, maxlen, buf, len, width, flags); } // An internal itoa-like function static size_t print_integer(out_fct_type out, char* buffer, size_t idx, size_t maxlen, printf_unsigned_value_t value, bool negative, numeric_base_t base, unsigned int precision, unsigned int width, unsigned int flags) { char buf[PRINTF_INTEGER_BUFFER_SIZE]; size_t len = 0U; if (!value) { if ( !(flags & FLAGS_PRECISION) ) { buf[len++] = '0'; flags &= ~FLAGS_HASH; // We drop this flag this since either the alternative and regular modes of the specifier // don't differ on 0 values, or (in the case of octal) we've already provided the special // handling for this mode. } else if (base == BASE_HEX) { flags &= ~FLAGS_HASH; // We drop this flag this since either the alternative and regular modes of the specifier // don't differ on 0 values } } else { do { const char digit = (char)(value % base); buf[len++] = (char)(digit < 10 ? '0' + digit : (flags & FLAGS_UPPERCASE ? 'A' : 'a') + digit - 10); value /= base; } while (value && (len < PRINTF_INTEGER_BUFFER_SIZE)); } return print_integer_finalization(out, buffer, idx, maxlen, buf, len, negative, base, precision, width, flags); } #if (CONFIG_LIBC_FLOAT || CONFIG_LIBC_FLOAT_EX) struct double_components { int_fast64_t integral; int_fast64_t fractional; bool is_negative; }; #define NUM_DECIMAL_DIGITS_IN_INT64_T 18 #define PRINTF_MAX_PRECOMPUTED_POWER_OF_10 NUM_DECIMAL_DIGITS_IN_INT64_T static const double powers_of_10[NUM_DECIMAL_DIGITS_IN_INT64_T] = { 1e00, 1e01, 1e02, 1e03, 1e04, 1e05, 1e06, 1e07, 1e08, 1e09, 1e10, 1e11, 1e12, 1e13, 1e14, 1e15, 1e16, 1e17 }; #define PRINTF_MAX_SUPPORTED_PRECISION NUM_DECIMAL_DIGITS_IN_INT64_T - 1 // Break up a double number - which is known to be a finite non-negative number - // into its base-10 parts: integral - before the decimal point, and fractional - after it. // Taken the precision into account, but does not change it even internally. static struct double_components get_components(double number, unsigned int precision) { struct double_components number_; number_.is_negative = get_sign(number); double abs_number = (number_.is_negative) ? -number : number; number_.integral = (int_fast64_t)abs_number; double remainder = (abs_number - number_.integral) * powers_of_10[precision]; number_.fractional = (int_fast64_t)remainder; remainder -= (double) number_.fractional; if (remainder > 0.5) { ++number_.fractional; // handle rollover, e.g. case 0.99 with precision 1 is 1.0 if ((double) number_.fractional >= powers_of_10[precision]) { number_.fractional = 0; ++number_.integral; } } else if (remainder == 0.5) { if ((number_.fractional == 0U) || (number_.fractional & 1U)) { // if halfway, round up if odd OR if last digit is 0 ++number_.fractional; } } if (precision == 0U) { remainder = abs_number - (double) number_.integral; if ((!(remainder < 0.5) || (remainder > 0.5)) && (number_.integral & 1)) { // exactly 0.5 and ODD, then round up // 1.5 -> 2, but 2.5 -> 2 ++number_.integral; } } return number_; } struct scaling_factor { double raw_factor; bool multiply; // if true, need to multiply by raw_factor; otherwise need to divide by it }; double apply_scaling(double num, struct scaling_factor normalization) { return normalization.multiply ? num * normalization.raw_factor : num / normalization.raw_factor; } double unapply_scaling(double normalized, struct scaling_factor normalization) { return normalization.multiply ? normalized / normalization.raw_factor : normalized * normalization.raw_factor; } struct scaling_factor update_normalization(struct scaling_factor sf, double extra_multiplicative_factor) { struct scaling_factor result; if (sf.multiply) { result.multiply = true; result.raw_factor = sf.raw_factor * extra_multiplicative_factor; } else { int factor_exp2 = get_exp2(get_bit_access(sf.raw_factor)); int extra_factor_exp2 = get_exp2(get_bit_access(extra_multiplicative_factor)); // Divide the larger-exponent raw raw_factor by the smaller if (PRINTF_ABS(factor_exp2) > PRINTF_ABS(extra_factor_exp2)) { result.multiply = false; result.raw_factor = sf.raw_factor / extra_multiplicative_factor; } else { result.multiply = true; result.raw_factor = extra_multiplicative_factor / sf.raw_factor; } } return result; } #if CONFIG_LIBC_FLOAT_EX static struct double_components get_normalized_components(bool negative, unsigned int precision, double non_normalized, struct scaling_factor normalization) { struct double_components components; components.is_negative = negative; components.integral = (int_fast64_t) apply_scaling(non_normalized, normalization); double remainder = non_normalized - unapply_scaling((double) components.integral, normalization); double prec_power_of_10 = powers_of_10[precision]; struct scaling_factor account_for_precision = update_normalization(normalization, prec_power_of_10); double scaled_remainder = apply_scaling(remainder, account_for_precision); double rounding_threshold = 0.5; if (precision == 0U) { components.fractional = 0; components.integral += (scaled_remainder >= rounding_threshold); if (scaled_remainder == rounding_threshold) { // banker's rounding: Round towards the even number (making the mean error 0) components.integral &= ~((int_fast64_t) 0x1); } } else { components.fractional = (int_fast64_t) scaled_remainder; scaled_remainder -= components.fractional; components.fractional += (scaled_remainder >= rounding_threshold); if (scaled_remainder == rounding_threshold) { // banker's rounding: Round towards the even number (making the mean error 0) components.fractional &= ~((int_fast64_t) 0x1); } // handle rollover, e.g. the case of 0.99 with precision 1 becoming (0,100), // and must then be corrected into (1, 0). if ((double) components.fractional >= prec_power_of_10) { components.fractional = 0; ++components.integral; } } return components; } #endif static size_t print_broken_up_decimal( struct double_components number_, out_fct_type out, char *buffer, size_t idx, size_t maxlen, unsigned int precision, unsigned int width, unsigned int flags, char *buf, size_t len) { if (precision != 0U) { // do fractional part, as an unsigned number unsigned int count = precision; if (flags & FLAGS_ADAPT_EXP && !(flags & FLAGS_HASH)) { // %g/%G mandates we skip the trailing 0 digits... if (number_.fractional > 0) { while(true) { int_fast64_t digit = number_.fractional % 10U; if (digit != 0) { break; } --count; number_.fractional /= 10U; } } // ... and even the decimal point if there are no // non-zero fractional part digits (see below) } if (number_.fractional > 0 || !(flags & FLAGS_ADAPT_EXP) || (flags & FLAGS_HASH) ) { while (len < PRINTF_FTOA_BUFFER_SIZE) { --count; buf[len++] = (char)('0' + number_.fractional % 10U); if (!(number_.fractional /= 10U)) { break; } } // add extra 0s while ((len < PRINTF_FTOA_BUFFER_SIZE) && (count-- > 0U)) { buf[len++] = '0'; } if (len < PRINTF_FTOA_BUFFER_SIZE) { buf[len++] = '.'; } } } else { if (flags & FLAGS_HASH) { if (len < PRINTF_FTOA_BUFFER_SIZE) { buf[len++] = '.'; } } } // Write the integer part of the number (it comes after the fractional // since the character order is reversed) while (len < PRINTF_FTOA_BUFFER_SIZE) { buf[len++] = (char)('0' + (number_.integral % 10)); if (!(number_.integral /= 10)) { break; } } // pad leading zeros if (!(flags & FLAGS_LEFT) && (flags & FLAGS_ZEROPAD)) { if (width && (number_.is_negative || (flags & (FLAGS_PLUS | FLAGS_SPACE)))) { width--; } while ((len < width) && (len < PRINTF_FTOA_BUFFER_SIZE)) { buf[len++] = '0'; } } if (len < PRINTF_FTOA_BUFFER_SIZE) { if (number_.is_negative) { buf[len++] = '-'; } else if (flags & FLAGS_PLUS) { buf[len++] = '+'; // ignore the space if the '+' exists } else if (flags & FLAGS_SPACE) { buf[len++] = ' '; } } return out_rev_(out, buffer, idx, maxlen, buf, len, width, flags); } // internal ftoa for fixed decimal floating point static size_t print_decimal_number(out_fct_type out, char* buffer, size_t idx, size_t maxlen, double number, unsigned int precision, unsigned int width, unsigned int flags, char* buf, size_t len) { struct double_components value_ = get_components(number, precision); return print_broken_up_decimal(value_, out, buffer, idx, maxlen, precision, width, flags, buf, len); } #if CONFIG_LIBC_FLOAT_EX // internal ftoa variant for exponential floating-point type, contributed by Martijn Jasperse static size_t print_exponential_number(out_fct_type out, char* buffer, size_t idx, size_t maxlen, double number, unsigned int precision, unsigned int width, unsigned int flags, char* buf, size_t len) { const bool negative = get_sign(number); // This number will decrease gradually (by factors of 10) as we "extract" the exponent out of it double abs_number = negative ? -number : number; int exp10; bool abs_exp10_covered_by_powers_table; struct scaling_factor normalization; // Determine the decimal exponent if (abs_number == 0.0) { // TODO: This is a special-case for 0.0 (and -0.0); but proper handling is required for denormals more generally. exp10 = 0; // ... and no need to set a normalization factor or check the powers table } else { double_with_bit_access conv = get_bit_access(abs_number); { // based on the algorithm by David Gay (https://www.ampl.com/netlib/fp/dtoa.c) int exp2 = get_exp2(conv); // drop the exponent, so conv.F comes into the range [1,2) conv.U = (conv.U & (( (double_uint_t)(1) << DOUBLE_STORED_MANTISSA_BITS) - 1U)) | ((double_uint_t) DOUBLE_BASE_EXPONENT << DOUBLE_STORED_MANTISSA_BITS); // now approximate log10 from the log2 integer part and an expansion of ln around 1.5 exp10 = (int)(0.1760912590558 + exp2 * 0.301029995663981 + (conv.F - 1.5) * 0.289529654602168); // now we want to compute 10^exp10 but we want to be sure it won't overflow exp2 = (int)(exp10 * 3.321928094887362 + 0.5); const double z = exp10 * 2.302585092994046 - exp2 * 0.6931471805599453; const double z2 = z * z; conv.U = ((double_uint_t)(exp2) + DOUBLE_BASE_EXPONENT) << DOUBLE_STORED_MANTISSA_BITS; // compute exp(z) using continued fractions, see https://en.wikipedia.org/wiki/Exponential_function#Continued_fractions_for_ex conv.F *= 1 + 2 * z / (2 - z + (z2 / (6 + (z2 / (10 + z2 / 14))))); // correct for rounding errors if (abs_number < conv.F) { exp10--; conv.F /= 10; } } abs_exp10_covered_by_powers_table = PRINTF_ABS(exp10) < PRINTF_MAX_PRECOMPUTED_POWER_OF_10; normalization.raw_factor = abs_exp10_covered_by_powers_table ? powers_of_10[PRINTF_ABS(exp10)] : conv.F; } // We now begin accounting for the widths of the two parts of our printed field: // the decimal part after decimal exponent extraction, and the base-10 exponent part. // For both of these, the value of 0 has a special meaning, but not the same one: // a 0 exponent-part width means "don't print the exponent"; a 0 decimal-part width // means "use as many characters as necessary". bool fall_back_to_decimal_only_mode = false; if (flags & FLAGS_ADAPT_EXP) { int required_significant_digits = (precision == 0) ? 1 : (int) precision; // Should we want to fall-back to "%f" mode, and only print the decimal part? fall_back_to_decimal_only_mode = (exp10 >= -4 && exp10 < required_significant_digits); // Now, let's adjust the precision // This also decided how we adjust the precision value - as in "%g" mode, // "precision" is the number of _significant digits_, and this is when we "translate" // the precision value to an actual number of decimal digits. int precision_ = (fall_back_to_decimal_only_mode) ? (int) precision - 1 - exp10 : (int) precision - 1; // the presence of the exponent ensures only one significant digit comes before the decimal point precision = (precision_ > 0 ? (unsigned) precision_ : 0U); flags |= FLAGS_PRECISION; // make sure print_broken_up_decimal respects our choice above } normalization.multiply = (exp10 < 0 && abs_exp10_covered_by_powers_table); bool should_skip_normalization = (fall_back_to_decimal_only_mode || exp10 == 0); struct double_components decimal_part_components = should_skip_normalization ? get_components(negative ? -abs_number : abs_number, precision) : get_normalized_components(negative, precision, abs_number, normalization); // Account for roll-over, e.g. rounding from 9.99 to 100.0 - which effects // the exponent and may require additional tweaking of the parts if (fall_back_to_decimal_only_mode) { if ( (flags & FLAGS_ADAPT_EXP) && exp10 >= -1 && decimal_part_components.integral == powers_of_10[exp10 + 1]) { exp10++; // Not strictly necessary, since exp10 is no longer really used precision--; // ... and it should already be the case that decimal_part_components.fractional == 0 } // TODO: What about rollover strictly within the fractional part? } else { if (decimal_part_components.integral >= 10) { exp10++; decimal_part_components.integral = 1; decimal_part_components.fractional = 0; } } // the exp10 format is "E%+03d" and largest possible exp10 value for a 64-bit double // is "307" (for 2^1023), so we set aside 4-5 characters overall unsigned int exp10_part_width = fall_back_to_decimal_only_mode ? 0U : (PRINTF_ABS(exp10) < 100) ? 4U : 5U; unsigned int decimal_part_width = ((flags & FLAGS_LEFT) && exp10_part_width) ? // We're padding on the right, so the width constraint is the exponent part's // problem, not the decimal part's, so we'll use as many characters as we need: 0U : // We're padding on the left; so the width constraint is the decimal part's // problem. Well, can both the decimal part and the exponent part fit within our overall width? ((width > exp10_part_width) ? // Yes, so we limit our decimal part's width. // (Note this is trivially valid even if we've fallen back to "%f" mode) width - exp10_part_width : // No; we just give up on any restriction on the decimal part and use as many // characters as we need 0U); const size_t start_idx = idx; idx = print_broken_up_decimal(decimal_part_components, out, buffer, idx, maxlen, precision, decimal_part_width, flags, buf, len); if (! fall_back_to_decimal_only_mode) { out((flags & FLAGS_UPPERCASE) ? 'E' : 'e', buffer, idx++, maxlen); idx = print_integer(out, buffer, idx, maxlen, ABS_FOR_PRINTING(exp10), exp10 < 0, 10, 0, exp10_part_width - 1, FLAGS_ZEROPAD | FLAGS_PLUS); if (flags & FLAGS_LEFT) { // We need to right-pad with spaces to meet the width requirement while (idx - start_idx < width) out(' ', buffer, idx++, maxlen); } } return idx; } #endif // CONFIG_LIBC_FLOAT_EX static size_t print_floating_point(out_fct_type out, char* buffer, size_t idx, size_t maxlen, double value, unsigned int precision, unsigned int width, unsigned int flags, bool prefer_exponential) { char buf[PRINTF_FTOA_BUFFER_SIZE]; size_t len = 0U; // test for special values if (value != value) return out_rev_(out, buffer, idx, maxlen, "nan", 3, width, flags); if (value < -DBL_MAX) return out_rev_(out, buffer, idx, maxlen, "fni-", 4, width, flags); if (value > DBL_MAX) return out_rev_(out, buffer, idx, maxlen, (flags & FLAGS_PLUS) ? "fni+" : "fni", (flags & FLAGS_PLUS) ? 4U : 3U, width, flags); if (!prefer_exponential && ((value > PRINTF_FLOAT_NOTATION_THRESHOLD) || (value < -PRINTF_FLOAT_NOTATION_THRESHOLD))) { // The required behavior of standard printf is to print _every_ integral-part digit -- which could mean // printing hundreds of characters, overflowing any fixed internal buffer and necessitating a more complicated // implementation. #if CONFIG_LIBC_FLOAT_EX return print_exponential_number(out, buffer, idx, maxlen, value, precision, width, flags, buf, len); #else return 0U; #endif } // set default precision, if not set explicitly if (!(flags & FLAGS_PRECISION)) { precision = PRINTF_DEFAULT_FLOAT_PRECISION; } // limit precision so that our integer holding the fractional part does not overflow while ((len < PRINTF_FTOA_BUFFER_SIZE) && (precision > PRINTF_MAX_SUPPORTED_PRECISION)) { buf[len++] = '0'; // This respects the precision in terms of result length only precision--; } return #if CONFIG_LIBC_FLOAT_EX prefer_exponential ? print_exponential_number(out, buffer, idx, maxlen, value, precision, width, flags, buf, len) : #endif print_decimal_number(out, buffer, idx, maxlen, value, precision, width, flags, buf, len); } #endif // (CONFIG_LIBC_FLOAT || CONFIG_LIBC_FLOAT_EX) // internal vsnprintf static int __vsnprintf(out_fct_type out, char* buffer, const size_t maxlen, const char* format, va_list va) { unsigned int flags, width, precision, n; size_t idx = 0U; if (!buffer) { // use null output function out = out_discard; } while (*format) { // format specifier? %[flags][width][.precision][length] if (*format != '%') { // no out(*format, buffer, idx++, maxlen); format++; continue; } else { // yes, evaluate it format++; } // evaluate flags flags = 0U; do { switch (*format) { case '0': flags |= FLAGS_ZEROPAD; format++; n = 1U; break; case '-': flags |= FLAGS_LEFT; format++; n = 1U; break; case '+': flags |= FLAGS_PLUS; format++; n = 1U; break; case ' ': flags |= FLAGS_SPACE; format++; n = 1U; break; case '#': flags |= FLAGS_HASH; format++; n = 1U; break; default : n = 0U; break; } } while (n); // evaluate width field width = 0U; if (is_digit_(*format)) { width = atoi_(&format); } else if (*format == '*') { const int w = va_arg(va, int); if (w < 0) { flags |= FLAGS_LEFT; // reverse padding width = (unsigned int)-w; } else { width = (unsigned int)w; } format++; } // evaluate precision field precision = 0U; if (*format == '.') { flags |= FLAGS_PRECISION; format++; if (is_digit_(*format)) { precision = atoi_(&format); } else if (*format == '*') { const int precision_ = (int)va_arg(va, int); precision = precision_ > 0 ? (unsigned int)precision_ : 0U; format++; } } #if PRINTF_SUPPORT_LENGTH_FILED // evaluate length field switch (*format) { case 'l' : flags |= FLAGS_LONG; format++; if (*format == 'l') { flags |= FLAGS_LONG_LONG; format++; } break; case 'h' : flags |= FLAGS_SHORT; format++; if (*format == 'h') { flags |= FLAGS_CHAR; format++; } break; case 't' : flags |= (sizeof(ptrdiff_t) == sizeof(long) ? FLAGS_LONG : FLAGS_LONG_LONG); format++; break; case 'j' : flags |= (sizeof(intmax_t) == sizeof(long) ? FLAGS_LONG : FLAGS_LONG_LONG); format++; break; case 'z' : flags |= (sizeof(size_t) == sizeof(long) ? FLAGS_LONG : FLAGS_LONG_LONG); format++; break; default: break; } #endif // evaluate specifier switch (*format) { case 'd' : case 'i' : case 'u' : case 'x' : case 'X' : case 'o' : case 'b' : { // set the base numeric_base_t base; if (*format == 'x' || *format == 'X') { base = BASE_HEX; } else if (*format == 'o') { base = BASE_OCTAL; } else if (*format == 'b') { base = BASE_BINARY; } else { base = BASE_DECIMAL; flags &= ~FLAGS_HASH; // no hash for dec format } // uppercase if (*format == 'X') { flags |= FLAGS_UPPERCASE; } // no plus or space flag for u, x, X, o, b if ((*format != 'i') && (*format != 'd')) { flags &= ~(FLAGS_PLUS | FLAGS_SPACE); } // ignore '0' flag when precision is given if (flags & FLAGS_PRECISION) { flags &= ~FLAGS_ZEROPAD; } // convert the integer if ((*format == 'i') || (*format == 'd')) { // signed if (flags & FLAGS_LONG_LONG) { #if CONFIG_LIBC_LONG_LONG const long long value = va_arg(va, long long); idx = print_integer(out, buffer, idx, maxlen, ABS_FOR_PRINTING(value), value < 0, base, precision, width, flags); #endif } else if (flags & FLAGS_LONG) { const long value = va_arg(va, long); idx = print_integer(out, buffer, idx, maxlen, ABS_FOR_PRINTING(value), value < 0, base, precision, width, flags); } else { const int value = (flags & FLAGS_CHAR) ? (signed char)va_arg(va, int) : (flags & FLAGS_SHORT) ? (short int)va_arg(va, int) : va_arg(va, int); idx = print_integer(out, buffer, idx, maxlen, ABS_FOR_PRINTING(value), value < 0, base, precision, width, flags); } } else { // unsigned if (flags & FLAGS_LONG_LONG) { #if CONFIG_LIBC_LONG_LONG idx = print_integer(out, buffer, idx, maxlen, (printf_unsigned_value_t) va_arg(va, unsigned long long), false, base, precision, width, flags); #endif } else if (flags & FLAGS_LONG) { idx = print_integer(out, buffer, idx, maxlen, (printf_unsigned_value_t) va_arg(va, unsigned long), false, base, precision, width, flags); } else { const unsigned int value = (flags & FLAGS_CHAR) ? (unsigned char)va_arg(va, unsigned int) : (flags & FLAGS_SHORT) ? (unsigned short int)va_arg(va, unsigned int) : va_arg(va, unsigned int); idx = print_integer(out, buffer, idx, maxlen, (printf_unsigned_value_t) value, false, base, precision, width, flags); } } format++; break; } #if CONFIG_LIBC_FLOAT case 'f' : case 'F' : if (*format == 'F') flags |= FLAGS_UPPERCASE; idx = print_floating_point(out, buffer, idx, maxlen, va_arg(va, double), precision, width, flags, PRINTF_PREFER_DECIMAL); format++; break; #endif #if CONFIG_LIBC_FLOAT_EX case 'e': case 'E': case 'g': case 'G': if ((*format == 'g')||(*format == 'G')) flags |= FLAGS_ADAPT_EXP; if ((*format == 'E')||(*format == 'G')) flags |= FLAGS_UPPERCASE; idx = print_floating_point(out, buffer, idx, maxlen, va_arg(va, double), precision, width, flags, PRINTF_PREFER_EXPONENTIAL); format++; break; #endif // CONFIG_LIBC_FLOAT_EX #if PRINTF_SUPPORT_CHAR case 'c' : { unsigned int l = 1U; // pre padding if (!(flags & FLAGS_LEFT)) { while (l++ < width) { out(' ', buffer, idx++, maxlen); } } // char output out((char)va_arg(va, int), buffer, idx++, maxlen); // post padding if (flags & FLAGS_LEFT) { while (l++ < width) { out(' ', buffer, idx++, maxlen); } } format++; break; } #endif case 's' : { const char* p = va_arg(va, char*); if (p == NULL) { idx = out_rev_(out, buffer, idx, maxlen, ")llun(", 6, width, flags); } else { unsigned int l = strnlen_s_(p, precision ? precision : (size_t)-1); // pre padding if (flags & FLAGS_PRECISION) { l = (l < precision ? l : precision); } if (!(flags & FLAGS_LEFT)) { while (l++ < width) { out(' ', buffer, idx++, maxlen); } } // string output while ((*p != 0) && (!(flags & FLAGS_PRECISION) || precision--)) { out(*(p++), buffer, idx++, maxlen); } // post padding if (flags & FLAGS_LEFT) { while (l++ < width) { out(' ', buffer, idx++, maxlen); } } } format++; break; } #if PRINTF_SUPPORT_ADDR case 'p' : { width = sizeof(void*) * 2U + 2; // 2 hex chars per byte + the "0x" prefix flags |= FLAGS_ZEROPAD | FLAGS_POINTER; uintptr_t value = (uintptr_t)va_arg(va, void*); idx = (value == (uintptr_t) NULL) ? out_rev_(out, buffer, idx, maxlen, ")lin(", 5, width, flags) : print_integer(out, buffer, idx, maxlen, (printf_unsigned_value_t) value, false, BASE_HEX, precision, width, flags); format++; break; } #endif case '%' : out('%', buffer, idx++, maxlen); format++; break; default : out(*format, buffer, idx++, maxlen); format++; break; } } // termination out((char)0, buffer, idx < maxlen ? idx : maxlen - 1U, maxlen); // return written chars without terminating \0 return (int)idx; } int vsnprintf (char *, size_t, const char *, va_list) __attribute__ ((alias ("_vsnprintf"))); int _vsnprintf(char *buf, size_t size, const char *fmt, va_list args) { return __vsnprintf(out_buffer, buf, size, fmt, args); }