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yaml-cpp
Commit f4bca79d by Simon Gene Gottlieb Committed by Jesse Beder
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fix: fp_to_string uses now 2 spaces

parent d4e00bd4
Showing with 146 additions and 146 deletions
include/yaml-cpp/fp_to_string.h
......@@ -20,9 +20,9 @@ namespace fp_formatting {
* Converts a integer into its ASCII digits.
*
* @param begin/end - a buffer, must be at least 20bytes long
* @param value - input value
* @param width - minimum number of digits, fill with '0' to the left. Must be equal or smaller than the buffer size.
* @return - number of digits filled into the buffer.
* @param value - input value
* @param width - minimum number of digits, fill with '0' to the left. Must be equal or smaller than the buffer size.
* @return - number of digits filled into the buffer.
*
* Example:
* std::array<char, 20> buffer;
......@@ -33,27 +33,27 @@ namespace fp_formatting {
* assert(buffer[2] == '3');
*/
inline auto ConvertToChars(char* begin, char* end, size_t value, int width=1) -> int {
assert(width >= 1);
assert(end >= begin); // end must be after begin
assert(end-begin >= width); // Buffer must be large enough
assert(end-begin >= 20); // 2^64 has 20digits, so at least 20 digits must be available
// count number of digits, and fill digits array accordingly
int digits_ct{};
while (value > 0) {
char c = value % 10 + '0';
value = value / 10;
digits_ct += 1;
*(end-digits_ct) = c;
}
while(digits_ct < width) {
assert(digits_ct < 64);
digits_ct += 1;
*(end-digits_ct) = '0';
}
// move data to the front of the array
std::memmove(begin, end-digits_ct, digits_ct);
return digits_ct;
assert(width >= 1);
assert(end >= begin); // end must be after begin
assert(end-begin >= width); // Buffer must be large enough
assert(end-begin >= 20); // 2^64 has 20digits, so at least 20 digits must be available
// count number of digits, and fill digits array accordingly
int digits_ct{};
while (value > 0) {
char c = value % 10 + '0';
value = value / 10;
digits_ct += 1;
*(end-digits_ct) = c;
}
while(digits_ct < width) {
assert(digits_ct < 64);
digits_ct += 1;
*(end-digits_ct) = '0';
}
// move data to the front of the array
std::memmove(begin, end-digits_ct, digits_ct);
return digits_ct;
}
/**
......@@ -63,144 +63,144 @@ inline auto ConvertToChars(char* begin, char* end, size_t value, int width=1) ->
*/
template <typename T>
auto FpToString(T v, int precision = 0) -> std::string {
// assert(precision > 0);
// hardcoded constant, at which exponent should switch to a scientific notation
int const lowerExponentThreshold = -5;
int const upperExponentThreshold = (precision==0)?6:precision;
if (precision == 0) {
precision = 6;
}
// dragonbox/to_decimal does not handle value 0, inf, NaN
if (v == 0 || std::isinf(v) || std::isnan(v)) {
std::stringstream ss;
ss << v;
return ss.str();
}
auto r = jkj::dragonbox::to_decimal(v);
auto digits = std::array<char, 20>{}; // max digits of size_t is 20.
auto digits_ct = ConvertToChars(digits.data(), digits.data() + digits.size(), r.significand);
// check if requested precision is lower than
// required digits for exact representation
if (digits_ct > precision) {
auto diff = digits_ct - precision;
r.exponent += diff;
digits_ct = precision;
// round numbers if required
if (digits[digits_ct] >= '5') {
int i{digits_ct-1};
digits[i] += 1;
while (digits[i] == '9'+1) {
digits_ct -= 1;
r.exponent += 1;
if (i > 0) {
digits[i-1] += 1;
i -= 1;
} else {
digits_ct = 1;
digits[0] = '1';
break;
}
}
// assert(precision > 0);
// hardcoded constant, at which exponent should switch to a scientific notation
int const lowerExponentThreshold = -5;
int const upperExponentThreshold = (precision==0)?6:precision;
if (precision == 0) {
precision = 6;
}
// dragonbox/to_decimal does not handle value 0, inf, NaN
if (v == 0 || std::isinf(v) || std::isnan(v)) {
std::stringstream ss;
ss << v;
return ss.str();
}
auto r = jkj::dragonbox::to_decimal(v);
auto digits = std::array<char, 20>{}; // max digits of size_t is 20.
auto digits_ct = ConvertToChars(digits.data(), digits.data() + digits.size(), r.significand);
// check if requested precision is lower than
// required digits for exact representation
if (digits_ct > precision) {
auto diff = digits_ct - precision;
r.exponent += diff;
digits_ct = precision;
// round numbers if required
if (digits[digits_ct] >= '5') {
int i{digits_ct-1};
digits[i] += 1;
while (digits[i] == '9'+1) {
digits_ct -= 1;
r.exponent += 1;
if (i > 0) {
digits[i-1] += 1;
i -= 1;
} else {
digits_ct = 1;
digits[0] = '1';
break;
}
}
}
std::array<char, 28> output_buffer; // max digits of size_t plus sign, a dot and 2 letters for 'e+' or 'e-' and 4 letters for the exponent
auto output_ptr = &output_buffer[0];
// print '-' symbol for negative numbers
if (r.is_negative) {
*(output_ptr++) = '-';
}
std::array<char, 28> output_buffer; // max digits of size_t plus sign, a dot and 2 letters for 'e+' or 'e-' and 4 letters for the exponent
auto output_ptr = &output_buffer[0];
// print '-' symbol for negative numbers
if (r.is_negative) {
*(output_ptr++) = '-';
}
// exponent if only a single non-zero digit is before the decimal point
int const exponent = r.exponent + digits_ct - 1;
// case 1: scientific notation
if (exponent >= upperExponentThreshold || exponent <= lowerExponentThreshold) {
// print first digit
*(output_ptr++) = digits[0];
// print digits after decimal point
if (digits_ct > 1) {
*(output_ptr++) = '.';
// print significant numbers after decimal point
for (int i{1}; i < digits_ct; ++i) {
*(output_ptr++) = digits[i];
}
}
*(output_ptr++) = 'e';
*(output_ptr++) = (exponent>=0)?'+':'-';
auto exp_digits = std::array<char, 20>{};
auto exp_digits_ct = ConvertToChars(exp_digits.data(), exp_digits.data() + exp_digits.size(), std::abs(exponent), /*.precision=*/ 2);
for (int i{0}; i < exp_digits_ct; ++i) {
*(output_ptr++) = exp_digits[i];
}
// exponent if only a single non-zero digit is before the decimal point
int const exponent = r.exponent + digits_ct - 1;
// case 1: scientific notation
if (exponent >= upperExponentThreshold || exponent <= lowerExponentThreshold) {
// print first digit
*(output_ptr++) = digits[0];
// print digits after decimal point
if (digits_ct > 1) {
*(output_ptr++) = '.';
// print significant numbers after decimal point
for (int i{1}; i < digits_ct; ++i) {
*(output_ptr++) = digits[i];
}
}
*(output_ptr++) = 'e';
*(output_ptr++) = (exponent>=0)?'+':'-';
auto exp_digits = std::array<char, 20>{};
auto exp_digits_ct = ConvertToChars(exp_digits.data(), exp_digits.data() + exp_digits.size(), std::abs(exponent), /*.precision=*/ 2);
for (int i{0}; i < exp_digits_ct; ++i) {
*(output_ptr++) = exp_digits[i];
}
// case 2: default notation
// case 2: default notation
} else {
auto const digits_end = digits.begin() + digits_ct;
auto digits_iter = digits.begin();
// print digits before point
int const before_decimal_digits = digits_ct + r.exponent;
if (before_decimal_digits > 0) {
// print digits before point
for (int i{0}; i < std::min(before_decimal_digits, digits_ct); ++i) {
*(output_ptr++) = *(digits_iter++);
}
// print trailing zeros before point
for (int i{0}; i < before_decimal_digits - digits_ct; ++i) {
*(output_ptr++) = '0';
}
// print 0 before point if none where printed before
} else {
auto const digits_end = digits.begin() + digits_ct;
auto digits_iter = digits.begin();
// print digits before point
int const before_decimal_digits = digits_ct + r.exponent;
if (before_decimal_digits > 0) {
// print digits before point
for (int i{0}; i < std::min(before_decimal_digits, digits_ct); ++i) {
*(output_ptr++) = *(digits_iter++);
}
// print trailing zeros before point
for (int i{0}; i < before_decimal_digits - digits_ct; ++i) {
*(output_ptr++) = '0';
}
// print 0 before point if none where printed before
} else {
*(output_ptr++) = '0';
}
*(output_ptr++) = '0';
}
if (digits_iter != digits_end) {
*(output_ptr++) = '.';
// print 0 afer decimal point, to fill until first digits
int const after_decimal_zeros = -digits_ct - r.exponent;
for (int i{0}; i < after_decimal_zeros; ++i) {
*(output_ptr++) = '0';
}
// print significant numbers after decimal point
for (;digits_iter < digits_end; ++digits_iter) {
*(output_ptr++) = *digits_iter;
}
}
if (digits_iter != digits_end) {
*(output_ptr++) = '.';
// print 0 afer decimal point, to fill until first digits
int const after_decimal_zeros = -digits_ct - r.exponent;
for (int i{0}; i < after_decimal_zeros; ++i) {
*(output_ptr++) = '0';
}
// print significant numbers after decimal point
for (;digits_iter < digits_end; ++digits_iter) {
*(output_ptr++) = *digits_iter;
}
}
*output_ptr = '\0';
return std::string{&output_buffer[0], output_ptr};
}
*output_ptr = '\0';
return std::string{&output_buffer[0], output_ptr};
}
}
}
inline auto FpToString(float v, size_t precision = 0) -> std::string {
return detail::fp_formatting::FpToString(v, precision);
return detail::fp_formatting::FpToString(v, precision);
}
inline auto FpToString(double v, size_t precision = 0) -> std::string {
return detail::fp_formatting::FpToString(v, precision);
return detail::fp_formatting::FpToString(v, precision);
}
/**
* dragonbox only works for floats/doubles not long double
*/
inline auto FpToString(long double v, size_t precision = std::numeric_limits<long double>::max_digits10) -> std::string {
std::stringstream ss;
ss.precision(precision);
ss.imbue(std::locale("C"));
ss << v;
return ss.str();
std::stringstream ss;
ss.imbue(std::locale("C"));
ss.precision(precision);
ss << v;
return ss.str();
}
}
......
test/fp_to_string_test.cpp
......@@ -9,12 +9,12 @@ namespace {
*/
template <typename T>
static std::string convert_with_stringstream(T v, size_t precision = 0) {
std::stringstream ss;
if (precision > 0) {
ss << std::setprecision(precision);
}
ss << v;
return ss.str();
std::stringstream ss;
if (precision > 0) {
ss << std::setprecision(precision);
}
ss << v;
return ss.str();
}
// Caution: Test involving 'convert_with_stringstream' are based on std::stringstream
......
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