double-conversion drop.

runtime/third_party/double-conversion/test/cctest/test-fast-dtoa.cc

+// Copyright 2006-2008 the V8 project authors. All rights reserved.
+
+#include <stdlib.h>
+
+#include "cctest.h"
+#include "diy-fp.h"
+#include "double.h"
+#include "fast-dtoa.h"
+#include "gay-precision.h"
+#include "gay-shortest.h"
+#include "utils.h"
+
+using namespace double_conversion;
+
+static const int kBufferSize = 100;
+
+
+// Removes trailing '0' digits.
+static void TrimRepresentation(Vector<char> representation) {
+  int len = strlen(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 = UINT64_2PART_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 = UINT64_2PART_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(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(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(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(10 >= length);
+  TrimRepresentation(buffer);
+  CHECK_EQ("35844466", buffer.start());
+  CHECK_EQ(299, point);
+
+  uint64_t smallest_normal64 = UINT64_2PART_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 = UINT64_2PART_C(0x000FFFFF, FFFFFFFF);
+  v = Double(largest_denormal64).value();
+  status = FastDtoa(v, FAST_DTOA_PRECISION, 17, buffer, &length, &point);
+  CHECK(status);
+  CHECK(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(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(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(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(succeeded*1.0/total > 0.85);
+  // However with less than 15 digits almost the algorithm should almost always
+  // succeed.
+  CHECK(succeeded_15*1.0/total_15 > 0.9999);
+}