v8/test/unittests/base/bignum-dtoa-unittest.cc

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#include "src/base/numbers/bignum-dtoa.h"

#include <stdlib.h>

#include "src/base/numbers/double.h"
#include "test/unittests/gay-fixed.h"
#include "test/unittests/gay-precision.h"
#include "test/unittests/gay-shortest.h"
#include "testing/gtest/include/gtest/gtest.h"

namespace v8 {

using BignumDtoaTest = ::testing::Test;

namespace base {
namespace test_bignum_dtoa {

// Removes trailing '0' digits (modifies {representation}). Can create an empty
// string if all digits are 0.
static void TrimRepresentation(char* representation) {
  size_t len = strlen(representation);
  while (len > 0 && representation[len - 1] == '0') --len;
  representation[len] = '\0';
}

static const int kBufferSize = 100;

TEST_F(BignumDtoaTest, BignumDtoaVariousDoubles) {
  char buffer_container[kBufferSize];
  Vector<char> buffer(buffer_container, kBufferSize);
  int length;
  int point;

  BignumDtoa(1.0, BIGNUM_DTOA_SHORTEST, 0, buffer, &length, &point);
  CHECK_EQ(0, strcmp("1", buffer.begin()));
  CHECK_EQ(1, point);

  BignumDtoa(1.0, BIGNUM_DTOA_FIXED, 3, buffer, &length, &point);
  CHECK_GE(3, length - point);
  TrimRepresentation(buffer.begin());
  CHECK_EQ(0, strcmp("1", buffer.begin()));
  CHECK_EQ(1, point);

  BignumDtoa(1.0, BIGNUM_DTOA_PRECISION, 3, buffer, &length, &point);
  CHECK_GE(3, length);
  TrimRepresentation(buffer.begin());
  CHECK_EQ(0, strcmp("1", buffer.begin()));
  CHECK_EQ(1, point);

  BignumDtoa(1.5, BIGNUM_DTOA_SHORTEST, 0, buffer, &length, &point);
  CHECK_EQ(0, strcmp("15", buffer.begin()));
  CHECK_EQ(1, point);

  BignumDtoa(1.5, BIGNUM_DTOA_FIXED, 10, buffer, &length, &point);
  CHECK_GE(10, length - point);
  TrimRepresentation(buffer.begin());
  CHECK_EQ(0, strcmp("15", buffer.begin()));
  CHECK_EQ(1, point);

  BignumDtoa(1.5, BIGNUM_DTOA_PRECISION, 10, buffer, &length, &point);
  CHECK_GE(10, length);
  TrimRepresentation(buffer.begin());
  CHECK_EQ(0, strcmp("15", buffer.begin()));
  CHECK_EQ(1, point);

  double min_double = 5e-324;
  BignumDtoa(min_double, BIGNUM_DTOA_SHORTEST, 0, buffer, &length, &point);
  CHECK_EQ(0, strcmp("5", buffer.begin()));
  CHECK_EQ(-323, point);

  BignumDtoa(min_double, BIGNUM_DTOA_FIXED, 5, buffer, &length, &point);
  CHECK_GE(5, length - point);
  TrimRepresentation(buffer.begin());
  CHECK_EQ(0, strcmp("", buffer.begin()));

  BignumDtoa(min_double, BIGNUM_DTOA_PRECISION, 5, buffer, &length, &point);
  CHECK_GE(5, length);
  TrimRepresentation(buffer.begin());
  CHECK_EQ(0, strcmp("49407", buffer.begin()));
  CHECK_EQ(-323, point);

  double max_double = 1.7976931348623157e308;
  BignumDtoa(max_double, BIGNUM_DTOA_SHORTEST, 0, buffer, &length, &point);
  CHECK_EQ(0, strcmp("17976931348623157", buffer.begin()));
  CHECK_EQ(309, point);

  BignumDtoa(max_double, BIGNUM_DTOA_PRECISION, 7, buffer, &length, &point);
  CHECK_GE(7, length);
  TrimRepresentation(buffer.begin());
  CHECK_EQ(0, strcmp("1797693", buffer.begin()));
  CHECK_EQ(309, point);

  BignumDtoa(4294967272.0, BIGNUM_DTOA_SHORTEST, 0, buffer, &length, &point);
  CHECK_EQ(0, strcmp("4294967272", buffer.begin()));
  CHECK_EQ(10, point);

  BignumDtoa(4294967272.0, BIGNUM_DTOA_FIXED, 5, buffer, &length, &point);
  CHECK_EQ(0, strcmp("429496727200000", buffer.begin()));
  CHECK_EQ(10, point);

  BignumDtoa(4294967272.0, BIGNUM_DTOA_PRECISION, 14, buffer, &length, &point);
  CHECK_GE(14, length);
  TrimRepresentation(buffer.begin());
  CHECK_EQ(0, strcmp("4294967272", buffer.begin()));
  CHECK_EQ(10, point);

  BignumDtoa(4.1855804968213567e298, BIGNUM_DTOA_SHORTEST, 0, buffer, &length,
             &point);
  CHECK_EQ(0, strcmp("4185580496821357", buffer.begin()));
  CHECK_EQ(299, point);

  BignumDtoa(4.1855804968213567e298, BIGNUM_DTOA_PRECISION, 20, buffer, &length,
             &point);
  CHECK_GE(20, length);
  TrimRepresentation(buffer.begin());
  CHECK_EQ(0, strcmp("41855804968213567225", buffer.begin()));
  CHECK_EQ(299, point);

  BignumDtoa(5.5626846462680035e-309, BIGNUM_DTOA_SHORTEST, 0, buffer, &length,
             &point);
  CHECK_EQ(0, strcmp("5562684646268003", buffer.begin()));
  CHECK_EQ(-308, point);

  BignumDtoa(5.5626846462680035e-309, BIGNUM_DTOA_PRECISION, 1, buffer, &length,
             &point);
  CHECK_GE(1, length);
  TrimRepresentation(buffer.begin());
  CHECK_EQ(0, strcmp("6", buffer.begin()));
  CHECK_EQ(-308, point);

  BignumDtoa(2147483648.0, BIGNUM_DTOA_SHORTEST, 0, buffer, &length, &point);
  CHECK_EQ(0, strcmp("2147483648", buffer.begin()));
  CHECK_EQ(10, point);

  BignumDtoa(2147483648.0, BIGNUM_DTOA_FIXED, 2, buffer, &length, &point);
  CHECK_GE(2, length - point);
  TrimRepresentation(buffer.begin());
  CHECK_EQ(0, strcmp("2147483648", buffer.begin()));
  CHECK_EQ(10, point);

  BignumDtoa(2147483648.0, BIGNUM_DTOA_PRECISION, 5, buffer, &length, &point);
  CHECK_GE(5, length);
  TrimRepresentation(buffer.begin());
  CHECK_EQ(0, strcmp("21475", buffer.begin()));
  CHECK_EQ(10, point);

  BignumDtoa(3.5844466002796428e+298, BIGNUM_DTOA_SHORTEST, 0, buffer, &length,
             &point);
  CHECK_EQ(0, strcmp("35844466002796428", buffer.begin()));
  CHECK_EQ(299, point);

  BignumDtoa(3.5844466002796428e+298, BIGNUM_DTOA_PRECISION, 10, buffer,
             &length, &point);
  CHECK_GE(10, length);
  TrimRepresentation(buffer.begin());
  CHECK_EQ(0, strcmp("35844466", buffer.begin()));
  CHECK_EQ(299, point);

  uint64_t smallest_normal64 = 0x0010'0000'0000'0000;
  double v = Double(smallest_normal64).value();
  BignumDtoa(v, BIGNUM_DTOA_SHORTEST, 0, buffer, &length, &point);
  CHECK_EQ(0, strcmp("22250738585072014", buffer.begin()));
  CHECK_EQ(-307, point);

  BignumDtoa(v, BIGNUM_DTOA_PRECISION, 20, buffer, &length, &point);
  CHECK_GE(20, length);
  TrimRepresentation(buffer.begin());
  CHECK_EQ(0, strcmp("22250738585072013831", buffer.begin()));
  CHECK_EQ(-307, point);

  uint64_t largest_denormal64 = 0x000F'FFFF'FFFF'FFFF;
  v = Double(largest_denormal64).value();
  BignumDtoa(v, BIGNUM_DTOA_SHORTEST, 0, buffer, &length, &point);
  CHECK_EQ(0, strcmp("2225073858507201", buffer.begin()));
  CHECK_EQ(-307, point);

  BignumDtoa(v, BIGNUM_DTOA_PRECISION, 20, buffer, &length, &point);
  CHECK_GE(20, length);
  TrimRepresentation(buffer.begin());
  CHECK_EQ(0, strcmp("2225073858507200889", buffer.begin()));
  CHECK_EQ(-307, point);

  BignumDtoa(4128420500802942e-24, BIGNUM_DTOA_SHORTEST, 0, buffer, &length,
             &point);
  CHECK_EQ(0, strcmp("4128420500802942", buffer.begin()));
  CHECK_EQ(-8, point);

  v = 3.9292015898194142585311918e-10;
  BignumDtoa(v, BIGNUM_DTOA_SHORTEST, 0, buffer, &length, &point);
  CHECK_EQ(0, strcmp("39292015898194143", buffer.begin()));

  v = 4194304.0;
  BignumDtoa(v, BIGNUM_DTOA_FIXED, 5, buffer, &length, &point);
  CHECK_GE(5, length - point);
  TrimRepresentation(buffer.begin());
  CHECK_EQ(0, strcmp("4194304", buffer.begin()));

  v = 3.3161339052167390562200598e-237;
  BignumDtoa(v, BIGNUM_DTOA_PRECISION, 19, buffer, &length, &point);
  CHECK_GE(19, length);
  TrimRepresentation(buffer.begin());
  CHECK_EQ(0, strcmp("3316133905216739056", buffer.begin()));
  CHECK_EQ(-236, point);

  v = 7.9885183916008099497815232e+191;
  BignumDtoa(v, BIGNUM_DTOA_PRECISION, 4, buffer, &length, &point);
  CHECK_GE(4, length);
  TrimRepresentation(buffer.begin());
  CHECK_EQ(0, strcmp("7989", buffer.begin()));
  CHECK_EQ(192, point);

  v = 1.0000000000000012800000000e+17;
  BignumDtoa(v, BIGNUM_DTOA_FIXED, 1, buffer, &length, &point);
  CHECK_GE(1, length - point);
  TrimRepresentation(buffer.begin());
  CHECK_EQ(0, strcmp("100000000000000128", buffer.begin()));
  CHECK_EQ(18, point);
}

TEST_F(BignumDtoaTest, BignumDtoaGayShortest) {
  char buffer_container[kBufferSize];
  Vector<char> buffer(buffer_container, kBufferSize);
  int length;
  int point;

  Vector<const PrecomputedShortest> precomputed =
      PrecomputedShortestRepresentations();
  for (int i = 0; i < precomputed.length(); ++i) {
    const PrecomputedShortest current_test = precomputed[i];
    double v = current_test.v;
    BignumDtoa(v, BIGNUM_DTOA_SHORTEST, 0, buffer, &length, &point);
    CHECK_EQ(current_test.decimal_point, point);
    CHECK_EQ(0, strcmp(current_test.representation, buffer.begin()));
  }
}

TEST_F(BignumDtoaTest, BignumDtoaGayFixed) {
  char buffer_container[kBufferSize];
  Vector<char> buffer(buffer_container, kBufferSize);
  int length;
  int point;

  Vector<const PrecomputedFixed> precomputed =
      PrecomputedFixedRepresentations();
  for (int i = 0; i < precomputed.length(); ++i) {
    const PrecomputedFixed current_test = precomputed[i];
    double v = current_test.v;
    int number_digits = current_test.number_digits;
    BignumDtoa(v, BIGNUM_DTOA_FIXED, number_digits, buffer, &length, &point);
    CHECK_EQ(current_test.decimal_point, point);
    CHECK_GE(number_digits, length - point);
    TrimRepresentation(buffer.begin());
    CHECK_EQ(0, strcmp(current_test.representation, buffer.begin()));
  }
}

TEST_F(BignumDtoaTest, BignumDtoaGayPrecision) {
  char buffer_container[kBufferSize];
  Vector<char> buffer(buffer_container, kBufferSize);
  int length;
  int point;

  Vector<const PrecomputedPrecision> precomputed =
      PrecomputedPrecisionRepresentations();
  for (int i = 0; i < precomputed.length(); ++i) {
    const PrecomputedPrecision current_test = precomputed[i];
    double v = current_test.v;
    int number_digits = current_test.number_digits;
    BignumDtoa(v, BIGNUM_DTOA_PRECISION, number_digits, buffer, &length,
               &point);
    CHECK_EQ(current_test.decimal_point, point);
    CHECK_GE(number_digits, length);
    TrimRepresentation(buffer.begin());
    CHECK_EQ(0, strcmp(current_test.representation, buffer.begin()));
  }
}

}  // namespace test_bignum_dtoa
}  // namespace base
}  // namespace v8