diff --git a/src/printf.c b/src/printf.c index c05232d..9839395 100644 --- a/src/printf.c +++ b/src/printf.c @@ -83,8 +83,8 @@ typedef void (*out_fct_type)(char character, void* buffer, size_t idx, size_t ma // wrapper (used as buffer) for output function type typedef struct { - void (*fct)(char character, void* arg); - void* arg; + void (*fct)(char character, void* arg); + void* arg; } out_fct_wrap_type; static inline void _out_buffer(char character, void* buffer, size_t idx, size_t maxlen); @@ -117,41 +117,41 @@ static int _vsnprintf(out_fct_type out, char* buffer, const size_t maxlen, const int kernaux_printf(void (*out)(char character, void* arg), void* arg, const char* format, ...) { - va_list va; - va_start(va, format); - const out_fct_wrap_type out_fct_wrap = { out, arg }; - const int ret = _vsnprintf(_out_fct, (char*)(uintptr_t)&out_fct_wrap, (size_t)-1, format, va); - va_end(va); - return ret; + va_list va; + va_start(va, format); + const out_fct_wrap_type out_fct_wrap = { out, arg }; + const int ret = _vsnprintf(_out_fct, (char*)(uintptr_t)&out_fct_wrap, (size_t)-1, format, va); + va_end(va); + return ret; } int kernaux_vprintf(void (*out)(char character, void* arg), void* arg, const char* format, va_list va) { - const out_fct_wrap_type out_fct_wrap = { out, arg }; - return _vsnprintf(_out_fct, (char*)(uintptr_t)&out_fct_wrap, (size_t)-1, format, va); + const out_fct_wrap_type out_fct_wrap = { out, arg }; + return _vsnprintf(_out_fct, (char*)(uintptr_t)&out_fct_wrap, (size_t)-1, format, va); } int kernaux_snprintf(char* buffer, size_t count, const char* format, ...) { - va_list va; - va_start(va, format); - const int ret = _vsnprintf(_out_buffer, buffer, count, format, va); - va_end(va); - return ret; + va_list va; + va_start(va, format); + const int ret = _vsnprintf(_out_buffer, buffer, count, format, va); + va_end(va); + return ret; } int kernaux_vsnprintf(char* buffer, size_t count, const char* format, va_list va) { - return _vsnprintf(_out_buffer, buffer, count, format, va); + return _vsnprintf(_out_buffer, buffer, count, format, va); } int kernaux_sprintf(char* buffer, const char* format, ...) { - va_list va; - va_start(va, format); - const int ret = _vsnprintf(_out_buffer, buffer, (size_t)-1, format, va); - va_end(va); - return ret; + va_list va; + va_start(va, format); + const int ret = _vsnprintf(_out_buffer, buffer, (size_t)-1, format, va); + va_end(va); + return ret; } @@ -159,27 +159,27 @@ int kernaux_sprintf(char* buffer, const char* format, ...) // internal buffer output void _out_buffer(char character, void* buffer, size_t idx, size_t maxlen) { - if (idx < maxlen) { - ((char*)buffer)[idx] = character; - } + if (idx < maxlen) { + ((char*)buffer)[idx] = character; + } } // internal null output void _out_null(char character, void* buffer, size_t idx, size_t maxlen) { - (void)character; (void)buffer; (void)idx; (void)maxlen; + (void)character; (void)buffer; (void)idx; (void)maxlen; } // internal output function wrapper void _out_fct(char character, void* buffer, size_t idx, size_t maxlen) { - (void)idx; (void)maxlen; - if (character) { - // buffer is the output fct pointer - ((out_fct_wrap_type*)buffer)->fct(character, ((out_fct_wrap_type*)buffer)->arg); - } + (void)idx; (void)maxlen; + if (character) { + // buffer is the output fct pointer + ((out_fct_wrap_type*)buffer)->fct(character, ((out_fct_wrap_type*)buffer)->arg); + } } @@ -187,9 +187,9 @@ void _out_fct(char character, void* buffer, size_t idx, size_t maxlen) // \return The length of the string (excluding the terminating 0) limited by 'maxsize' unsigned int _strnlen_s(const char* str, size_t maxsize) { - const char* s; - for (s = str; *s && maxsize--; ++s); - return (unsigned int)(s - str); + const char* s; + for (s = str; *s && maxsize--; ++s); + return (unsigned int)(s - str); } @@ -197,124 +197,124 @@ unsigned int _strnlen_s(const char* str, size_t maxsize) // \return true if char is a digit bool _is_digit(char ch) { - return (ch >= '0') && (ch <= '9'); + return (ch >= '0') && (ch <= '9'); } // internal ASCII string to unsigned int conversion unsigned int _atoi(const char** str) { - unsigned int i = 0u; - while (_is_digit(**str)) { - i = i * 10u + (unsigned int)(*((*str)++) - '0'); - } - return i; + 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 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; + 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); + // 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); + // reverse string + while (len) { + out(buf[--len], buffer, idx++, maxlen); } - } - return idx; + // append pad spaces up to given width + if (flags & FLAGS_LEFT) { + while (idx - start_idx < width) { + out(' ', buffer, idx++, maxlen); + } + } + + return idx; } // internal itoa format size_t _ntoa_format(out_fct_type out, char* buffer, size_t idx, size_t maxlen, char* buf, size_t len, bool negative, unsigned int base, unsigned int prec, unsigned int width, unsigned int flags) { - // pad leading zeros - if (!(flags & FLAGS_LEFT)) { - if (width && (flags & FLAGS_ZEROPAD) && (negative || (flags & (FLAGS_PLUS | FLAGS_SPACE)))) { - width--; + // pad leading zeros + if (!(flags & FLAGS_LEFT)) { + if (width && (flags & FLAGS_ZEROPAD) && (negative || (flags & (FLAGS_PLUS | FLAGS_SPACE)))) { + width--; + } + while ((len < prec) && (len < PRINTF_NTOA_BUFFER_SIZE)) { + buf[len++] = '0'; + } + while ((flags & FLAGS_ZEROPAD) && (len < width) && (len < PRINTF_NTOA_BUFFER_SIZE)) { + buf[len++] = '0'; + } } - while ((len < prec) && (len < PRINTF_NTOA_BUFFER_SIZE)) { - buf[len++] = '0'; - } - while ((flags & FLAGS_ZEROPAD) && (len < width) && (len < PRINTF_NTOA_BUFFER_SIZE)) { - buf[len++] = '0'; - } - } - // handle hash - if (flags & FLAGS_HASH) { - if (!(flags & FLAGS_PRECISION) && len && ((len == prec) || (len == width))) { - len--; - if (len && (base == 16u)) { - len--; - } - } - if ((base == 16u) && !(flags & FLAGS_UPPERCASE) && (len < PRINTF_NTOA_BUFFER_SIZE)) { - buf[len++] = 'x'; - } - else if ((base == 16u) && (flags & FLAGS_UPPERCASE) && (len < PRINTF_NTOA_BUFFER_SIZE)) { - buf[len++] = 'X'; - } - else if ((base == 2u) && (len < PRINTF_NTOA_BUFFER_SIZE)) { - buf[len++] = 'b'; + // handle hash + if (flags & FLAGS_HASH) { + if (!(flags & FLAGS_PRECISION) && len && ((len == prec) || (len == width))) { + len--; + if (len && (base == 16u)) { + len--; + } + } + if ((base == 16u) && !(flags & FLAGS_UPPERCASE) && (len < PRINTF_NTOA_BUFFER_SIZE)) { + buf[len++] = 'x'; + } + else if ((base == 16u) && (flags & FLAGS_UPPERCASE) && (len < PRINTF_NTOA_BUFFER_SIZE)) { + buf[len++] = 'X'; + } + else if ((base == 2u) && (len < PRINTF_NTOA_BUFFER_SIZE)) { + buf[len++] = 'b'; + } + if (len < PRINTF_NTOA_BUFFER_SIZE) { + buf[len++] = '0'; + } } + if (len < PRINTF_NTOA_BUFFER_SIZE) { - buf[len++] = '0'; + if (negative) { + buf[len++] = '-'; + } + else if (flags & FLAGS_PLUS) { + buf[len++] = '+'; // ignore the space if the '+' exists + } + else if (flags & FLAGS_SPACE) { + buf[len++] = ' '; + } } - } - if (len < PRINTF_NTOA_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); + return _out_rev(out, buffer, idx, maxlen, buf, len, width, flags); } // internal itoa for 'long' type size_t _ntoa_long(out_fct_type out, char* buffer, size_t idx, size_t maxlen, unsigned long value, bool negative, unsigned long base, unsigned int prec, unsigned int width, unsigned int flags) { - char buf[PRINTF_NTOA_BUFFER_SIZE]; - size_t len = 0u; + char buf[PRINTF_NTOA_BUFFER_SIZE]; + size_t len = 0u; - // no hash for 0 values - if (!value) { - flags &= ~FLAGS_HASH; - } + // no hash for 0 values + if (!value) { + flags &= ~FLAGS_HASH; + } - // write if precision != 0 and value is != 0 - if (!(flags & FLAGS_PRECISION) || value) { - do { - const char digit = (char)(value % base); - buf[len++] = digit < 10 ? '0' + digit : (flags & FLAGS_UPPERCASE ? 'A' : 'a') + digit - 10; - value /= base; - } while (value && (len < PRINTF_NTOA_BUFFER_SIZE)); - } + // write if precision != 0 and value is != 0 + if (!(flags & FLAGS_PRECISION) || value) { + do { + const char digit = (char)(value % base); + buf[len++] = digit < 10 ? '0' + digit : (flags & FLAGS_UPPERCASE ? 'A' : 'a') + digit - 10; + value /= base; + } while (value && (len < PRINTF_NTOA_BUFFER_SIZE)); + } - return _ntoa_format(out, buffer, idx, maxlen, buf, len, negative, (unsigned int)base, prec, width, flags); + return _ntoa_format(out, buffer, idx, maxlen, buf, len, negative, (unsigned int)base, prec, width, flags); } @@ -322,24 +322,24 @@ size_t _ntoa_long(out_fct_type out, char* buffer, size_t idx, size_t maxlen, uns #ifdef PRINTF_SUPPORT_LONG_LONG size_t _ntoa_long_long(out_fct_type out, char* buffer, size_t idx, size_t maxlen, unsigned long long value, bool negative, unsigned long long base, unsigned int prec, unsigned int width, unsigned int flags) { - char buf[PRINTF_NTOA_BUFFER_SIZE]; - size_t len = 0u; + char buf[PRINTF_NTOA_BUFFER_SIZE]; + size_t len = 0u; - // no hash for 0 values - if (!value) { - flags &= ~FLAGS_HASH; - } + // no hash for 0 values + if (!value) { + flags &= ~FLAGS_HASH; + } - // write if precision != 0 and value is != 0 - if (!(flags & FLAGS_PRECISION) || value) { - do { - const char digit = (char)(value % base); - buf[len++] = digit < 10 ? '0' + digit : (flags & FLAGS_UPPERCASE ? 'A' : 'a') + digit - 10; - value /= base; - } while (value && (len < PRINTF_NTOA_BUFFER_SIZE)); - } + // write if precision != 0 and value is != 0 + if (!(flags & FLAGS_PRECISION) || value) { + do { + const char digit = (char)(value % base); + buf[len++] = digit < 10 ? '0' + digit : (flags & FLAGS_UPPERCASE ? 'A' : 'a') + digit - 10; + value /= base; + } while (value && (len < PRINTF_NTOA_BUFFER_SIZE)); + } - return _ntoa_format(out, buffer, idx, maxlen, buf, len, negative, (unsigned int)base, prec, width, flags); + return _ntoa_format(out, buffer, idx, maxlen, buf, len, negative, (unsigned int)base, prec, width, flags); } #endif // PRINTF_SUPPORT_LONG_LONG @@ -348,127 +348,127 @@ size_t _ntoa_long_long(out_fct_type out, char* buffer, size_t idx, size_t maxlen // internal ftoa for fixed decimal floating point size_t _ftoa(out_fct_type out, char* buffer, size_t idx, size_t maxlen, double value, unsigned int prec, unsigned int width, unsigned int flags) { - char buf[PRINTF_FTOA_BUFFER_SIZE]; - size_t len = 0u; - double diff = 0.0; + char buf[PRINTF_FTOA_BUFFER_SIZE]; + size_t len = 0u; + double diff = 0.0; - // powers of 10 - static const double pow10[] = { 1, 10, 100, 1000, 10000, 100000, 1000000, 10000000, 100000000, 1000000000 }; + // powers of 10 + static const double pow10[] = { 1, 10, 100, 1000, 10000, 100000, 1000000, 10000000, 100000000, 1000000000 }; - // 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); + // 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); - // test for very large values - // standard printf behavior is to print EVERY whole number digit -- which could be 100s of characters overflowing your buffers == bad - if ((value > PRINTF_MAX_FLOAT) || (value < -PRINTF_MAX_FLOAT)) { + // test for very large values + // standard printf behavior is to print EVERY whole number digit -- which could be 100s of characters overflowing your buffers == bad + if ((value > PRINTF_MAX_FLOAT) || (value < -PRINTF_MAX_FLOAT)) { #ifdef PRINTF_SUPPORT_EXPONENTIAL - return _etoa(out, buffer, idx, maxlen, value, prec, width, flags); + return _etoa(out, buffer, idx, maxlen, value, prec, width, flags); #else - return 0u; + return 0u; #endif - } - - // test for negative - bool negative = false; - if (value < 0) { - negative = true; - value = 0 - value; - } - - // set default precision, if not set explicitly - if (!(flags & FLAGS_PRECISION)) { - prec = PRINTF_DEFAULT_FLOAT_PRECISION; - } - // limit precision to 9, cause a prec >= 10 can lead to overflow errors - while ((len < PRINTF_FTOA_BUFFER_SIZE) && (prec > 9u)) { - buf[len++] = '0'; - prec--; - } - - int whole = (int)value; - double tmp = (value - whole) * pow10[prec]; - unsigned long frac = (unsigned long)tmp; - diff = tmp - frac; - - if (diff > 0.5) { - ++frac; - // handle rollover, e.g. case 0.99 with prec 1 is 1.0 - if (frac >= pow10[prec]) { - frac = 0; - ++whole; } - } - else if (diff < 0.5) { - } - else if ((frac == 0u) || (frac & 1u)) { - // if halfway, round up if odd OR if last digit is 0 - ++frac; - } - if (prec == 0u) { - diff = value - (double)whole; - if ((!(diff < 0.5) || (diff > 0.5)) && (whole & 1)) { - // exactly 0.5 and ODD, then round up - // 1.5 -> 2, but 2.5 -> 2 - ++whole; + // test for negative + bool negative = false; + if (value < 0) { + negative = true; + value = 0 - value; } - } - else { - unsigned int count = prec; - // now do fractional part, as an unsigned number + + // set default precision, if not set explicitly + if (!(flags & FLAGS_PRECISION)) { + prec = PRINTF_DEFAULT_FLOAT_PRECISION; + } + // limit precision to 9, cause a prec >= 10 can lead to overflow errors + while ((len < PRINTF_FTOA_BUFFER_SIZE) && (prec > 9u)) { + buf[len++] = '0'; + prec--; + } + + int whole = (int)value; + double tmp = (value - whole) * pow10[prec]; + unsigned long frac = (unsigned long)tmp; + diff = tmp - frac; + + if (diff > 0.5) { + ++frac; + // handle rollover, e.g. case 0.99 with prec 1 is 1.0 + if (frac >= pow10[prec]) { + frac = 0; + ++whole; + } + } + else if (diff < 0.5) { + } + else if ((frac == 0u) || (frac & 1u)) { + // if halfway, round up if odd OR if last digit is 0 + ++frac; + } + + if (prec == 0u) { + diff = value - (double)whole; + if ((!(diff < 0.5) || (diff > 0.5)) && (whole & 1)) { + // exactly 0.5 and ODD, then round up + // 1.5 -> 2, but 2.5 -> 2 + ++whole; + } + } + else { + unsigned int count = prec; + // now do fractional part, as an unsigned number + while (len < PRINTF_FTOA_BUFFER_SIZE) { + --count; + buf[len++] = (char)(48u + (frac % 10u)); + if (!(frac /= 10u)) { + break; + } + } + // add extra 0s + while ((len < PRINTF_FTOA_BUFFER_SIZE) && (count-- > 0u)) { + buf[len++] = '0'; + } + if (len < PRINTF_FTOA_BUFFER_SIZE) { + // add decimal + buf[len++] = '.'; + } + } + + // do whole part, number is reversed while (len < PRINTF_FTOA_BUFFER_SIZE) { - --count; - buf[len++] = (char)(48u + (frac % 10u)); - if (!(frac /= 10u)) { - break; - } + buf[len++] = (char)(48 + (whole % 10)); + if (!(whole /= 10)) { + break; + } } - // add extra 0s - while ((len < PRINTF_FTOA_BUFFER_SIZE) && (count-- > 0u)) { - buf[len++] = '0'; + + // pad leading zeros + if (!(flags & FLAGS_LEFT) && (flags & FLAGS_ZEROPAD)) { + if (width && (negative || (flags & (FLAGS_PLUS | FLAGS_SPACE)))) { + width--; + } + while ((len < width) && (len < PRINTF_FTOA_BUFFER_SIZE)) { + buf[len++] = '0'; + } } + if (len < PRINTF_FTOA_BUFFER_SIZE) { - // add decimal - buf[len++] = '.'; + if (negative) { + buf[len++] = '-'; + } + else if (flags & FLAGS_PLUS) { + buf[len++] = '+'; // ignore the space if the '+' exists + } + else if (flags & FLAGS_SPACE) { + buf[len++] = ' '; + } } - } - // do whole part, number is reversed - while (len < PRINTF_FTOA_BUFFER_SIZE) { - buf[len++] = (char)(48 + (whole % 10)); - if (!(whole /= 10)) { - break; - } - } - - // pad leading zeros - if (!(flags & FLAGS_LEFT) && (flags & FLAGS_ZEROPAD)) { - if (width && (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 (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); + return _out_rev(out, buffer, idx, maxlen, buf, len, width, flags); } @@ -476,108 +476,108 @@ size_t _ftoa(out_fct_type out, char* buffer, size_t idx, size_t maxlen, double v // internal ftoa variant for exponential floating-point type, contributed by Martijn Jasperse size_t _etoa(out_fct_type out, char* buffer, size_t idx, size_t maxlen, double value, unsigned int prec, unsigned int width, unsigned int flags) { - // check for NaN and special values - if ((value != value) || (value > DBL_MAX) || (value < -DBL_MAX)) { - return _ftoa(out, buffer, idx, maxlen, value, prec, width, flags); - } - - // determine the sign - const bool negative = value < 0; - if (negative) { - value = -value; - } - - // default precision - if (!(flags & FLAGS_PRECISION)) { - prec = PRINTF_DEFAULT_FLOAT_PRECISION; - } - - // determine the decimal exponent - // based on the algorithm by David Gay (https://www.ampl.com/netlib/fp/dtoa.c) - union { - uint64_t U; - double F; - } conv; - - conv.F = value; - int exp2 = (int)((conv.U >> 52u) & 0x07FFU) - 1023; // effectively log2 - conv.U = (conv.U & ((1ull << 52u) - 1u)) | (102ull << 52u); // drop the exponent so conv.F is now in [1,2) - // now approximate log10 from the log2 integer part and an expansion of ln around 1.5 - int expval = (int)(0.1760912590558 + exp2 * 0.301029995663981 + (conv.F - 1.5) * 0.289529654602168); - // now we want to compute 10^expval but we want to be sure it won't overflow - exp2 = (int)(expval * 3.321928094887362 + 0.5); - const double z = expval * 2.302585092994046 - exp2 * 0.6931471805599453; - const double z2 = z * z; - conv.U = (uint64_t)(exp2 + 1023) << 52u; - // 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 (value < conv.F) { - expval--; - conv.F /= 10; - } - - // the exponent format is "%+03d" and largest value is "307", so set aside 4-5 characters - unsigned int minwidth = ((expval < 100) && (expval > -100)) ? 4u : 5u; - - // in "%g" mode, "prec" is the number of *significant figures* not decimals - if (flags & FLAGS_ADAPT_EXP) { - // do we want to fall-back to "%f" mode? - if ((value >= 1e-4) && (value < 1e6)) { - if ((int)prec > expval) { - prec = (unsigned)((int)prec - expval - 1); - } - else { - prec = 0; - } - flags |= FLAGS_PRECISION; // make sure _ftoa respects precision - // no characters in exponent - minwidth = 0u; - expval = 0; + // check for NaN and special values + if ((value != value) || (value > DBL_MAX) || (value < -DBL_MAX)) { + return _ftoa(out, buffer, idx, maxlen, value, prec, width, flags); } - else { - // we use one sigfig for the whole part - if ((prec > 0) && (flags & FLAGS_PRECISION)) { - --prec; - } + + // determine the sign + const bool negative = value < 0; + if (negative) { + value = -value; } - } - // will everything fit? - unsigned int fwidth = width; - if (width > minwidth) { - // we didn't fall-back so subtract the characters required for the exponent - fwidth -= minwidth; - } else { - // not enough characters, so go back to default sizing - fwidth = 0u; - } - if ((flags & FLAGS_LEFT) && minwidth) { - // if we're padding on the right, DON'T pad the floating part - fwidth = 0u; - } - - // rescale the float value - if (expval) { - value /= conv.F; - } - - // output the floating part - const size_t start_idx = idx; - idx = _ftoa(out, buffer, idx, maxlen, negative ? -value : value, prec, fwidth, flags & ~FLAGS_ADAPT_EXP); - - // output the exponent part - if (minwidth) { - // output the exponential symbol - out((flags & FLAGS_UPPERCASE) ? 'E' : 'e', buffer, idx++, maxlen); - // output the exponent value - idx = _ntoa_long(out, buffer, idx, maxlen, (expval < 0) ? -expval : expval, expval < 0, 10, 0, minwidth-1, FLAGS_ZEROPAD | FLAGS_PLUS); - // might need to right-pad spaces - if (flags & FLAGS_LEFT) { - while (idx - start_idx < width) out(' ', buffer, idx++, maxlen); + // default precision + if (!(flags & FLAGS_PRECISION)) { + prec = PRINTF_DEFAULT_FLOAT_PRECISION; } - } - return idx; + + // determine the decimal exponent + // based on the algorithm by David Gay (https://www.ampl.com/netlib/fp/dtoa.c) + union { + uint64_t U; + double F; + } conv; + + conv.F = value; + int exp2 = (int)((conv.U >> 52u) & 0x07FFU) - 1023; // effectively log2 + conv.U = (conv.U & ((1ull << 52u) - 1u)) | (102ull << 52u); // drop the exponent so conv.F is now in [1,2) + // now approximate log10 from the log2 integer part and an expansion of ln around 1.5 + int expval = (int)(0.1760912590558 + exp2 * 0.301029995663981 + (conv.F - 1.5) * 0.289529654602168); + // now we want to compute 10^expval but we want to be sure it won't overflow + exp2 = (int)(expval * 3.321928094887362 + 0.5); + const double z = expval * 2.302585092994046 - exp2 * 0.6931471805599453; + const double z2 = z * z; + conv.U = (uint64_t)(exp2 + 1023) << 52u; + // 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 (value < conv.F) { + expval--; + conv.F /= 10; + } + + // the exponent format is "%+03d" and largest value is "307", so set aside 4-5 characters + unsigned int minwidth = ((expval < 100) && (expval > -100)) ? 4u : 5u; + + // in "%g" mode, "prec" is the number of *significant figures* not decimals + if (flags & FLAGS_ADAPT_EXP) { + // do we want to fall-back to "%f" mode? + if ((value >= 1e-4) && (value < 1e6)) { + if ((int)prec > expval) { + prec = (unsigned)((int)prec - expval - 1); + } + else { + prec = 0; + } + flags |= FLAGS_PRECISION; // make sure _ftoa respects precision + // no characters in exponent + minwidth = 0u; + expval = 0; + } + else { + // we use one sigfig for the whole part + if ((prec > 0) && (flags & FLAGS_PRECISION)) { + --prec; + } + } + } + + // will everything fit? + unsigned int fwidth = width; + if (width > minwidth) { + // we didn't fall-back so subtract the characters required for the exponent + fwidth -= minwidth; + } else { + // not enough characters, so go back to default sizing + fwidth = 0u; + } + if ((flags & FLAGS_LEFT) && minwidth) { + // if we're padding on the right, DON'T pad the floating part + fwidth = 0u; + } + + // rescale the float value + if (expval) { + value /= conv.F; + } + + // output the floating part + const size_t start_idx = idx; + idx = _ftoa(out, buffer, idx, maxlen, negative ? -value : value, prec, fwidth, flags & ~FLAGS_ADAPT_EXP); + + // output the exponent part + if (minwidth) { + // output the exponential symbol + out((flags & FLAGS_UPPERCASE) ? 'E' : 'e', buffer, idx++, maxlen); + // output the exponent value + idx = _ntoa_long(out, buffer, idx, maxlen, (expval < 0) ? -expval : expval, expval < 0, 10, 0, minwidth-1, FLAGS_ZEROPAD | FLAGS_PLUS); + // might need to right-pad spaces + if (flags & FLAGS_LEFT) { + while (idx - start_idx < width) out(' ', buffer, idx++, maxlen); + } + } + return idx; } #endif // PRINTF_SUPPORT_EXPONENTIAL #endif // ENABLE_FLOAT @@ -586,282 +586,286 @@ size_t _etoa(out_fct_type out, char* buffer, size_t idx, size_t maxlen, double v // internal vsnprintf 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; + unsigned int flags, width, precision, n; + size_t idx = 0u; - if (!buffer) { - // use null output function - out = _out_null; - } - - while (*format) - { - // format specifier? %[flags][width][.precision][length] - if (*format != '%') { - // no - out(*format, buffer, idx++, maxlen); - format++; - continue; - } - else { - // yes, evaluate it - format++; + if (!buffer) { + // use null output function + out = _out_null; } - // 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 prec = (int)va_arg(va, int); - precision = prec > 0 ? (unsigned int)prec : 0u; - format++; - } - } - - // evaluate length field - switch (*format) { - case 'l' : - flags |= FLAGS_LONG; - format++; - if (*format == 'l') { - flags |= FLAGS_LONG_LONG; - format++; + while (*format) + { + // format specifier? %[flags][width][.precision][length] + if (*format != '%') { + // no + out(*format, buffer, idx++, maxlen); + format++; + continue; } - break; - case 'h' : - flags |= FLAGS_SHORT; - format++; - if (*format == 'h') { - flags |= FLAGS_CHAR; - format++; + else { + // yes, evaluate it + format++; } - break; + + // 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 prec = (int)va_arg(va, int); + precision = prec > 0 ? (unsigned int)prec : 0u; + format++; + } + } + + // evaluate length field + switch (*format) { + case 'l' : + flags |= FLAGS_LONG; + format++; + if (*format == 'l') { + flags |= FLAGS_LONG_LONG; + format++; + } + break; + case 'h' : + flags |= FLAGS_SHORT; + format++; + if (*format == 'h') { + flags |= FLAGS_CHAR; + format++; + } + break; #ifdef PRINTF_SUPPORT_PTRDIFF_T - case 't' : - flags |= (sizeof(ptrdiff_t) == sizeof(long) ? FLAGS_LONG : FLAGS_LONG_LONG); - format++; - break; + case 't' : + flags |= (sizeof(ptrdiff_t) == sizeof(long) ? FLAGS_LONG : FLAGS_LONG_LONG); + format++; + break; #endif - case 'j' : - flags |= (sizeof(intmax_t) == sizeof(long) ? FLAGS_LONG : FLAGS_LONG_LONG); - format++; - break; - case 'z' : - flags |= (sizeof(size_t) == sizeof(long) ? FLAGS_LONG : FLAGS_LONG_LONG); - format++; - break; - default : - break; - } - - // evaluate specifier - switch (*format) { - case 'd' : - case 'i' : - case 'u' : - case 'x' : - case 'X' : - case 'o' : - case 'b' : { - // set the base - unsigned int base; - if (*format == 'x' || *format == 'X') { - base = 16u; - } - else if (*format == 'o') { - base = 8u; - } - else if (*format == 'b') { - base = 2u; - } - else { - base = 10u; - flags &= ~FLAGS_HASH; // no hash for dec format - } - // uppercase - if (*format == 'X') { - flags |= FLAGS_UPPERCASE; + 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; } - // no plus or space flag for u, x, X, o, b - if ((*format != 'i') && (*format != 'd')) { - flags &= ~(FLAGS_PLUS | FLAGS_SPACE); - } + // evaluate specifier + switch (*format) { + case 'd' : + case 'i' : + case 'u' : + case 'x' : + case 'X' : + case 'o' : + case 'b' : + { + // set the base + unsigned int base; + if (*format == 'x' || *format == 'X') { + base = 16u; + } + else if (*format == 'o') { + base = 8u; + } + else if (*format == 'b') { + base = 2u; + } + else { + base = 10u; + flags &= ~FLAGS_HASH; // no hash for dec format + } + // uppercase + if (*format == 'X') { + flags |= FLAGS_UPPERCASE; + } - // ignore '0' flag when precision is given - if (flags & FLAGS_PRECISION) { - flags &= ~FLAGS_ZEROPAD; - } + // no plus or space flag for u, x, X, o, b + if ((*format != 'i') && (*format != 'd')) { + flags &= ~(FLAGS_PLUS | FLAGS_SPACE); + } - // convert the integer - if ((*format == 'i') || (*format == 'd')) { - // signed - if (flags & FLAGS_LONG_LONG) { + // 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) { #ifdef PRINTF_SUPPORT_LONG_LONG - const long long value = va_arg(va, long long); - idx = _ntoa_long_long(out, buffer, idx, maxlen, (unsigned long long)(value > 0 ? value : 0 - value), value < 0, base, precision, width, flags); + const long long value = va_arg(va, long long); + idx = _ntoa_long_long(out, buffer, idx, maxlen, (unsigned long long)(value > 0 ? value : 0 - value), value < 0, base, precision, width, flags); #endif - } - else if (flags & FLAGS_LONG) { - const long value = va_arg(va, long); - idx = _ntoa_long(out, buffer, idx, maxlen, (unsigned long)(value > 0 ? value : 0 - value), value < 0, base, precision, width, flags); - } - else { - const int value = (flags & FLAGS_CHAR) ? (char)va_arg(va, int) : (flags & FLAGS_SHORT) ? (short int)va_arg(va, int) : va_arg(va, int); - idx = _ntoa_long(out, buffer, idx, maxlen, (unsigned int)(value > 0 ? value : 0 - value), value < 0, base, precision, width, flags); - } - } - else { - // unsigned - if (flags & FLAGS_LONG_LONG) { + } + else if (flags & FLAGS_LONG) { + const long value = va_arg(va, long); + idx = _ntoa_long(out, buffer, idx, maxlen, (unsigned long)(value > 0 ? value : 0 - value), value < 0, base, precision, width, flags); + } + else { + const int value = (flags & FLAGS_CHAR) ? (char)va_arg(va, int) : (flags & FLAGS_SHORT) ? (short int)va_arg(va, int) : va_arg(va, int); + idx = _ntoa_long(out, buffer, idx, maxlen, (unsigned int)(value > 0 ? value : 0 - value), value < 0, base, precision, width, flags); + } + } + else { + // unsigned + if (flags & FLAGS_LONG_LONG) { #ifdef PRINTF_SUPPORT_LONG_LONG - idx = _ntoa_long_long(out, buffer, idx, maxlen, va_arg(va, unsigned long long), false, base, precision, width, flags); + idx = _ntoa_long_long(out, buffer, idx, maxlen, va_arg(va, unsigned long long), false, base, precision, width, flags); #endif - } - else if (flags & FLAGS_LONG) { - idx = _ntoa_long(out, buffer, idx, maxlen, 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 = _ntoa_long(out, buffer, idx, maxlen, value, false, base, precision, width, flags); - } - } - format++; - break; - } + } + else if (flags & FLAGS_LONG) { + idx = _ntoa_long(out, buffer, idx, maxlen, 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 = _ntoa_long(out, buffer, idx, maxlen, value, false, base, precision, width, flags); + } + } + format++; + break; + } #ifdef ENABLE_FLOAT - case 'f' : - case 'F' : - if (*format == 'F') flags |= FLAGS_UPPERCASE; - idx = _ftoa(out, buffer, idx, maxlen, va_arg(va, double), precision, width, flags); - format++; - break; + case 'f' : + case 'F' : + if (*format == 'F') flags |= FLAGS_UPPERCASE; + idx = _ftoa(out, buffer, idx, maxlen, va_arg(va, double), precision, width, flags); + format++; + break; #ifdef PRINTF_SUPPORT_EXPONENTIAL - 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 = _etoa(out, buffer, idx, maxlen, va_arg(va, double), precision, width, flags); - format++; - break; + 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 = _etoa(out, buffer, idx, maxlen, va_arg(va, double), precision, width, flags); + format++; + break; #endif // PRINTF_SUPPORT_EXPONENTIAL #endif // ENABLE_FLOAT - case 'c' : { - unsigned int l = 1u; - // pre padding - if (!(flags & FLAGS_LEFT)) { - while (l++ < width) { - out(' ', buffer, idx++, maxlen); - } - } - // char output - out((char)va_arg(va, int), buffer, idx++, maxlen); - // post padding - if (flags & FLAGS_LEFT) { - while (l++ < width) { - out(' ', buffer, idx++, maxlen); - } - } - format++; - break; - } + case 'c': + { + unsigned int l = 1u; + // pre padding + if (!(flags & FLAGS_LEFT)) { + while (l++ < width) { + out(' ', buffer, idx++, maxlen); + } + } + // char output + out((char)va_arg(va, int), buffer, idx++, maxlen); + // post padding + if (flags & FLAGS_LEFT) { + while (l++ < width) { + out(' ', buffer, idx++, maxlen); + } + } + format++; + break; + } - case 's' : { - const char* p = va_arg(va, char*); - unsigned int l = _strnlen_s(p, precision ? precision : (size_t)-1); - // pre padding - if (flags & FLAGS_PRECISION) { - l = (l < precision ? l : precision); - } - if (!(flags & FLAGS_LEFT)) { - while (l++ < width) { - out(' ', buffer, idx++, maxlen); - } - } - // string output - while ((*p != 0) && (!(flags & FLAGS_PRECISION) || precision--)) { - out(*(p++), buffer, idx++, maxlen); - } - // post padding - if (flags & FLAGS_LEFT) { - while (l++ < width) { - out(' ', buffer, idx++, maxlen); - } - } - format++; - break; - } + case 's': + { + const char* p = va_arg(va, char*); + unsigned int l = _strnlen_s(p, precision ? precision : (size_t)-1); + // pre padding + if (flags & FLAGS_PRECISION) { + l = (l < precision ? l : precision); + } + if (!(flags & FLAGS_LEFT)) { + while (l++ < width) { + out(' ', buffer, idx++, maxlen); + } + } + // string output + while ((*p != 0) && (!(flags & FLAGS_PRECISION) || precision--)) { + out(*(p++), buffer, idx++, maxlen); + } + // post padding + if (flags & FLAGS_LEFT) { + while (l++ < width) { + out(' ', buffer, idx++, maxlen); + } + } + format++; + break; + } - case 'p' : { - width = sizeof(void*) * 2u; - flags |= FLAGS_ZEROPAD | FLAGS_UPPERCASE; + case 'p': + { + width = sizeof(void*) * 2u; + flags |= FLAGS_ZEROPAD | FLAGS_UPPERCASE; #ifdef PRINTF_SUPPORT_LONG_LONG - const bool is_ll = sizeof(uintptr_t) == sizeof(long long); - if (is_ll) { - idx = _ntoa_long_long(out, buffer, idx, maxlen, (uintptr_t)va_arg(va, void*), false, 16u, precision, width, flags); - } - else { + const bool is_ll = sizeof(uintptr_t) == sizeof(long long); + if (is_ll) { + idx = _ntoa_long_long(out, buffer, idx, maxlen, (uintptr_t)va_arg(va, void*), false, 16u, precision, width, flags); + } + else { #endif - idx = _ntoa_long(out, buffer, idx, maxlen, (unsigned long)((uintptr_t)va_arg(va, void*)), false, 16u, precision, width, flags); + idx = _ntoa_long(out, buffer, idx, maxlen, (unsigned long)((uintptr_t)va_arg(va, void*)), false, 16u, precision, width, flags); #ifdef PRINTF_SUPPORT_LONG_LONG - } + } #endif - format++; - break; - } + format++; + break; + } - case '%' : - out('%', buffer, idx++, maxlen); - format++; - break; + case '%' : + out('%', buffer, idx++, maxlen); + format++; + break; - default : - out(*format, buffer, idx++, maxlen); - format++; - break; + default : + out(*format, buffer, idx++, maxlen); + format++; + break; + } } - } - // termination - out((char)0, buffer, idx < maxlen ? idx : maxlen - 1u, maxlen); + // termination + out((char)0, buffer, idx < maxlen ? idx : maxlen - 1u, maxlen); - // return written chars without terminating \0 - return (int)idx; + // return written chars without terminating \0 + return (int)idx; }