v8/test/cctest/test-fast-dtoa.cc

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// Copyright 2006-2008 the V8 project authors. All rights reserved.
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following
// disclaimer in the documentation and/or other materials provided
// with the distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived
// from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (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 <stdlib.h>
#include "src/v8.h"
#include "src/base/platform/platform.h"
#include "src/diy-fp.h"
#include "src/double.h"
#include "src/fast-dtoa.h"
#include "test/cctest/cctest.h"
#include "test/cctest/gay-precision.h"
#include "test/cctest/gay-shortest.h"
using namespace v8::internal;
static const int kBufferSize = 100;
// Removes trailing '0' digits.
static void TrimRepresentation(Vector<char> representation) {
int len = StrLength(representation.start());
int i;
for (i = len - 1; i >= 0; --i) {
if (representation[i] != '0') break;
}
representation[i + 1] = '\0';
}
TEST(FastDtoaShortestVariousDoubles) {
char buffer_container[kBufferSize];
Vector<char> buffer(buffer_container, kBufferSize);
int length;
int point;
int status;
double min_double = 5e-324;
status = FastDtoa(min_double, FAST_DTOA_SHORTEST, 0,
buffer, &length, &point);
CHECK(status);
CHECK_EQ("5", buffer.start());
CHECK_EQ(-323, point);
double max_double = 1.7976931348623157e308;
status = FastDtoa(max_double, FAST_DTOA_SHORTEST, 0,
buffer, &length, &point);
CHECK(status);
CHECK_EQ("17976931348623157", buffer.start());
CHECK_EQ(309, point);
status = FastDtoa(4294967272.0, FAST_DTOA_SHORTEST, 0,
buffer, &length, &point);
CHECK(status);
CHECK_EQ("4294967272", buffer.start());
CHECK_EQ(10, point);
status = FastDtoa(4.1855804968213567e298, FAST_DTOA_SHORTEST, 0,
buffer, &length, &point);
CHECK(status);
CHECK_EQ("4185580496821357", buffer.start());
CHECK_EQ(299, point);
status = FastDtoa(5.5626846462680035e-309, FAST_DTOA_SHORTEST, 0,
buffer, &length, &point);
CHECK(status);
CHECK_EQ("5562684646268003", buffer.start());
CHECK_EQ(-308, point);
status = FastDtoa(2147483648.0, FAST_DTOA_SHORTEST, 0,
buffer, &length, &point);
CHECK(status);
CHECK_EQ("2147483648", buffer.start());
CHECK_EQ(10, point);
status = FastDtoa(3.5844466002796428e+298, FAST_DTOA_SHORTEST, 0,
buffer, &length, &point);
if (status) { // Not all FastDtoa variants manage to compute this number.
CHECK_EQ("35844466002796428", buffer.start());
CHECK_EQ(299, point);
}
uint64_t smallest_normal64 = V8_2PART_UINT64_C(0x00100000, 00000000);
double v = Double(smallest_normal64).value();
status = FastDtoa(v, FAST_DTOA_SHORTEST, 0, buffer, &length, &point);
if (status) {
CHECK_EQ("22250738585072014", buffer.start());
CHECK_EQ(-307, point);
}
uint64_t largest_denormal64 = V8_2PART_UINT64_C(0x000FFFFF, FFFFFFFF);
v = Double(largest_denormal64).value();
status = FastDtoa(v, FAST_DTOA_SHORTEST, 0, buffer, &length, &point);
if (status) {
CHECK_EQ("2225073858507201", buffer.start());
CHECK_EQ(-307, point);
}
}
TEST(FastDtoaPrecisionVariousDoubles) {
char buffer_container[kBufferSize];
Vector<char> buffer(buffer_container, kBufferSize);
int length;
int point;
int status;
status = FastDtoa(1.0, FAST_DTOA_PRECISION, 3, buffer, &length, &point);
CHECK(status);
CHECK_GE(3, length);
TrimRepresentation(buffer);
CHECK_EQ("1", buffer.start());
CHECK_EQ(1, point);
status = FastDtoa(1.5, FAST_DTOA_PRECISION, 10, buffer, &length, &point);
if (status) {
CHECK_GE(10, length);
TrimRepresentation(buffer);
CHECK_EQ("15", buffer.start());
CHECK_EQ(1, point);
}
double min_double = 5e-324;
status = FastDtoa(min_double, FAST_DTOA_PRECISION, 5,
buffer, &length, &point);
CHECK(status);
CHECK_EQ("49407", buffer.start());
CHECK_EQ(-323, point);
double max_double = 1.7976931348623157e308;
status = FastDtoa(max_double, FAST_DTOA_PRECISION, 7,
buffer, &length, &point);
CHECK(status);
CHECK_EQ("1797693", buffer.start());
CHECK_EQ(309, point);
status = FastDtoa(4294967272.0, FAST_DTOA_PRECISION, 14,
buffer, &length, &point);
if (status) {
CHECK_GE(14, length);
TrimRepresentation(buffer);
CHECK_EQ("4294967272", buffer.start());
CHECK_EQ(10, point);
}
status = FastDtoa(4.1855804968213567e298, FAST_DTOA_PRECISION, 17,
buffer, &length, &point);
CHECK(status);
CHECK_EQ("41855804968213567", buffer.start());
CHECK_EQ(299, point);
status = FastDtoa(5.5626846462680035e-309, FAST_DTOA_PRECISION, 1,
buffer, &length, &point);
CHECK(status);
CHECK_EQ("6", buffer.start());
CHECK_EQ(-308, point);
status = FastDtoa(2147483648.0, FAST_DTOA_PRECISION, 5,
buffer, &length, &point);
CHECK(status);
CHECK_EQ("21475", buffer.start());
CHECK_EQ(10, point);
status = FastDtoa(3.5844466002796428e+298, FAST_DTOA_PRECISION, 10,
buffer, &length, &point);
CHECK(status);
CHECK_GE(10, length);
TrimRepresentation(buffer);
CHECK_EQ("35844466", buffer.start());
CHECK_EQ(299, point);
uint64_t smallest_normal64 = V8_2PART_UINT64_C(0x00100000, 00000000);
double v = Double(smallest_normal64).value();
status = FastDtoa(v, FAST_DTOA_PRECISION, 17, buffer, &length, &point);
CHECK(status);
CHECK_EQ("22250738585072014", buffer.start());
CHECK_EQ(-307, point);
uint64_t largest_denormal64 = V8_2PART_UINT64_C(0x000FFFFF, FFFFFFFF);
v = Double(largest_denormal64).value();
status = FastDtoa(v, FAST_DTOA_PRECISION, 17, buffer, &length, &point);
CHECK(status);
CHECK_GE(20, length);
TrimRepresentation(buffer);
CHECK_EQ("22250738585072009", buffer.start());
CHECK_EQ(-307, point);
v = 3.3161339052167390562200598e-237;
status = FastDtoa(v, FAST_DTOA_PRECISION, 18, buffer, &length, &point);
CHECK(status);
CHECK_EQ("331613390521673906", buffer.start());
CHECK_EQ(-236, point);
v = 7.9885183916008099497815232e+191;
status = FastDtoa(v, FAST_DTOA_PRECISION, 4, buffer, &length, &point);
CHECK(status);
CHECK_EQ("7989", buffer.start());
CHECK_EQ(192, point);
}
TEST(FastDtoaGayShortest) {
char buffer_container[kBufferSize];
Vector<char> buffer(buffer_container, kBufferSize);
bool status;
int length;
int point;
int succeeded = 0;
int total = 0;
bool needed_max_length = false;
Vector<const PrecomputedShortest> precomputed =
PrecomputedShortestRepresentations();
for (int i = 0; i < precomputed.length(); ++i) {
const PrecomputedShortest current_test = precomputed[i];
total++;
double v = current_test.v;
status = FastDtoa(v, FAST_DTOA_SHORTEST, 0, buffer, &length, &point);
CHECK_GE(kFastDtoaMaximalLength, length);
if (!status) continue;
if (length == kFastDtoaMaximalLength) needed_max_length = true;
succeeded++;
CHECK_EQ(current_test.decimal_point, point);
CHECK_EQ(current_test.representation, buffer.start());
}
CHECK_GT(succeeded*1.0/total, 0.99);
CHECK(needed_max_length);
}
TEST(FastDtoaGayPrecision) {
char buffer_container[kBufferSize];
Vector<char> buffer(buffer_container, kBufferSize);
bool status;
int length;
int point;
int succeeded = 0;
int total = 0;
// Count separately for entries with less than 15 requested digits.
int succeeded_15 = 0;
int total_15 = 0;
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;
total++;
if (number_digits <= 15) total_15++;
status = FastDtoa(v, FAST_DTOA_PRECISION, number_digits,
buffer, &length, &point);
CHECK_GE(number_digits, length);
if (!status) continue;
succeeded++;
if (number_digits <= 15) succeeded_15++;
TrimRepresentation(buffer);
CHECK_EQ(current_test.decimal_point, point);
CHECK_EQ(current_test.representation, buffer.start());
}
// The precomputed numbers contain many entries with many requested
// digits. These have a high failure rate and we therefore expect a lower
// success rate than for the shortest representation.
CHECK_GT(succeeded*1.0/total, 0.85);
// However with less than 15 digits almost the algorithm should almost always
// succeed.
CHECK_GT(succeeded_15*1.0/total_15, 0.9999);
}