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DoubleConversion 2020-12-17 (0d3733a4)
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Code extracted from:

    https://github.com/google/double-conversion

at commit 0d3733a4168dd739f45cef8a55718f8b02ee3073 (0d3733a4168dd739f45cef8a55718f8b02ee3073).
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@floitschG @bradking
floitschG authored and bradking committed Aug 5, 2022
1 parent 25368a2 commit 8f0ef9b
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Showing 18 changed files with 2,072 additions and 1,645 deletions.
46 changes: 23 additions & 23 deletions bignum-dtoa.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -25,7 +25,7 @@
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

#include <math.h>
#include <cmath>

#include "bignum-dtoa.h"

Expand All @@ -35,7 +35,7 @@
namespace double_conversion {

static int NormalizedExponent(uint64_t significand, int exponent) {
ASSERT(significand != 0);
DOUBLE_CONVERSION_ASSERT(significand != 0);
while ((significand & Double::kHiddenBit) == 0) {
significand = significand << 1;
exponent = exponent - 1;
Expand Down Expand Up @@ -76,26 +76,26 @@ static void GenerateShortestDigits(Bignum* numerator, Bignum* denominator,
// Generates 'requested_digits' after the decimal point.
static void BignumToFixed(int requested_digits, int* decimal_point,
Bignum* numerator, Bignum* denominator,
Vector<char>(buffer), int* length);
Vector<char> buffer, int* length);
// Generates 'count' digits of numerator/denominator.
// Once 'count' digits have been produced rounds the result depending on the
// remainder (remainders of exactly .5 round upwards). Might update the
// decimal_point when rounding up (for example for 0.9999).
static void GenerateCountedDigits(int count, int* decimal_point,
Bignum* numerator, Bignum* denominator,
Vector<char>(buffer), int* length);
Vector<char> buffer, int* length);


void BignumDtoa(double v, BignumDtoaMode mode, int requested_digits,
Vector<char> buffer, int* length, int* decimal_point) {
ASSERT(v > 0);
ASSERT(!Double(v).IsSpecial());
DOUBLE_CONVERSION_ASSERT(v > 0);
DOUBLE_CONVERSION_ASSERT(!Double(v).IsSpecial());
uint64_t significand;
int exponent;
bool lower_boundary_is_closer;
if (mode == BIGNUM_DTOA_SHORTEST_SINGLE) {
float f = static_cast<float>(v);
ASSERT(f == v);
DOUBLE_CONVERSION_ASSERT(f == v);
significand = Single(f).Significand();
exponent = Single(f).Exponent();
lower_boundary_is_closer = Single(f).LowerBoundaryIsCloser();
Expand Down Expand Up @@ -134,7 +134,7 @@ void BignumDtoa(double v, BignumDtoaMode mode, int requested_digits,
// 4e-324. In this case the denominator needs fewer than 324*4 binary digits.
// The maximum double is 1.7976931348623157e308 which needs fewer than
// 308*4 binary digits.
ASSERT(Bignum::kMaxSignificantBits >= 324*4);
DOUBLE_CONVERSION_ASSERT(Bignum::kMaxSignificantBits >= 324*4);
InitialScaledStartValues(significand, exponent, lower_boundary_is_closer,
estimated_power, need_boundary_deltas,
&numerator, &denominator,
Expand Down Expand Up @@ -163,7 +163,7 @@ void BignumDtoa(double v, BignumDtoaMode mode, int requested_digits,
buffer, length);
break;
default:
UNREACHABLE();
DOUBLE_CONVERSION_UNREACHABLE();
}
buffer[*length] = '\0';
}
Expand Down Expand Up @@ -195,7 +195,7 @@ static void GenerateShortestDigits(Bignum* numerator, Bignum* denominator,
for (;;) {
uint16_t digit;
digit = numerator->DivideModuloIntBignum(*denominator);
ASSERT(digit <= 9); // digit is a uint16_t and therefore always positive.
DOUBLE_CONVERSION_ASSERT(digit <= 9); // digit is a uint16_t and therefore always positive.
// digit = numerator / denominator (integer division).
// numerator = numerator % denominator.
buffer[(*length)++] = static_cast<char>(digit + '0');
Expand Down Expand Up @@ -241,7 +241,7 @@ static void GenerateShortestDigits(Bignum* numerator, Bignum* denominator,
// loop would have stopped earlier.
// We still have an assert here in case the preconditions were not
// satisfied.
ASSERT(buffer[(*length) - 1] != '9');
DOUBLE_CONVERSION_ASSERT(buffer[(*length) - 1] != '9');
buffer[(*length) - 1]++;
} else {
// Halfway case.
Expand All @@ -252,7 +252,7 @@ static void GenerateShortestDigits(Bignum* numerator, Bignum* denominator,
if ((buffer[(*length) - 1] - '0') % 2 == 0) {
// Round down => Do nothing.
} else {
ASSERT(buffer[(*length) - 1] != '9');
DOUBLE_CONVERSION_ASSERT(buffer[(*length) - 1] != '9');
buffer[(*length) - 1]++;
}
}
Expand All @@ -264,9 +264,9 @@ static void GenerateShortestDigits(Bignum* numerator, Bignum* denominator,
// Round up.
// Note again that the last digit could not be '9' since this would have
// stopped the loop earlier.
// We still have an ASSERT here, in case the preconditions were not
// We still have an DOUBLE_CONVERSION_ASSERT here, in case the preconditions were not
// satisfied.
ASSERT(buffer[(*length) -1] != '9');
DOUBLE_CONVERSION_ASSERT(buffer[(*length) -1] != '9');
buffer[(*length) - 1]++;
return;
}
Expand All @@ -283,11 +283,11 @@ static void GenerateShortestDigits(Bignum* numerator, Bignum* denominator,
static void GenerateCountedDigits(int count, int* decimal_point,
Bignum* numerator, Bignum* denominator,
Vector<char> buffer, int* length) {
ASSERT(count >= 0);
DOUBLE_CONVERSION_ASSERT(count >= 0);
for (int i = 0; i < count - 1; ++i) {
uint16_t digit;
digit = numerator->DivideModuloIntBignum(*denominator);
ASSERT(digit <= 9); // digit is a uint16_t and therefore always positive.
DOUBLE_CONVERSION_ASSERT(digit <= 9); // digit is a uint16_t and therefore always positive.
// digit = numerator / denominator (integer division).
// numerator = numerator % denominator.
buffer[i] = static_cast<char>(digit + '0');
Expand All @@ -300,7 +300,7 @@ static void GenerateCountedDigits(int count, int* decimal_point,
if (Bignum::PlusCompare(*numerator, *numerator, *denominator) >= 0) {
digit++;
}
ASSERT(digit <= 10);
DOUBLE_CONVERSION_ASSERT(digit <= 10);
buffer[count - 1] = static_cast<char>(digit + '0');
// Correct bad digits (in case we had a sequence of '9's). Propagate the
// carry until we hat a non-'9' or til we reach the first digit.
Expand All @@ -325,7 +325,7 @@ static void GenerateCountedDigits(int count, int* decimal_point,
// Input verifies: 1 <= (numerator + delta) / denominator < 10.
static void BignumToFixed(int requested_digits, int* decimal_point,
Bignum* numerator, Bignum* denominator,
Vector<char>(buffer), int* length) {
Vector<char> buffer, int* length) {
// Note that we have to look at more than just the requested_digits, since
// a number could be rounded up. Example: v=0.5 with requested_digits=0.
// Even though the power of v equals 0 we can't just stop here.
Expand All @@ -341,7 +341,7 @@ static void BignumToFixed(int requested_digits, int* decimal_point,
} else if (-(*decimal_point) == requested_digits) {
// We only need to verify if the number rounds down or up.
// Ex: 0.04 and 0.06 with requested_digits == 1.
ASSERT(*decimal_point == -requested_digits);
DOUBLE_CONVERSION_ASSERT(*decimal_point == -requested_digits);
// Initially the fraction lies in range (1, 10]. Multiply the denominator
// by 10 so that we can compare more easily.
denominator->Times10();
Expand Down Expand Up @@ -370,7 +370,7 @@ static void BignumToFixed(int requested_digits, int* decimal_point,
// Returns an estimation of k such that 10^(k-1) <= v < 10^k where
// v = f * 2^exponent and 2^52 <= f < 2^53.
// v is hence a normalized double with the given exponent. The output is an
// approximation for the exponent of the decimal approimation .digits * 10^k.
// approximation for the exponent of the decimal approximation .digits * 10^k.
//
// The result might undershoot by 1 in which case 10^k <= v < 10^k+1.
// Note: this property holds for v's upper boundary m+ too.
Expand Down Expand Up @@ -420,7 +420,7 @@ static void InitialScaledStartValuesPositiveExponent(
Bignum* numerator, Bignum* denominator,
Bignum* delta_minus, Bignum* delta_plus) {
// A positive exponent implies a positive power.
ASSERT(estimated_power >= 0);
DOUBLE_CONVERSION_ASSERT(estimated_power >= 0);
// Since the estimated_power is positive we simply multiply the denominator
// by 10^estimated_power.

Expand Down Expand Up @@ -506,7 +506,7 @@ static void InitialScaledStartValuesNegativeExponentNegativePower(
// numerator = v * 10^-estimated_power * 2 * 2^-exponent.
// Remember: numerator has been abused as power_ten. So no need to assign it
// to itself.
ASSERT(numerator == power_ten);
DOUBLE_CONVERSION_ASSERT(numerator == power_ten);
numerator->MultiplyByUInt64(significand);

// denominator = 2 * 2^-exponent with exponent < 0.
Expand Down Expand Up @@ -548,7 +548,7 @@ static void InitialScaledStartValuesNegativeExponentNegativePower(
//
// Let ep == estimated_power, then the returned values will satisfy:
// v / 10^ep = numerator / denominator.
// v's boundarys m- and m+:
// v's boundaries m- and m+:
// m- / 10^ep == v / 10^ep - delta_minus / denominator
// m+ / 10^ep == v / 10^ep + delta_plus / denominator
// Or in other words:
Expand Down
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