base/strings/string_number_conversions_unittest.cc - Issue 2044643005: Add strtod test cases

Unified Diff: base/strings/string_number_conversions_unittest.cc

Issue 2044643005: Add strtod test cases (Closed) Base URL: https://chromium.googlesource.com/chromium/src.git@master

Patch Set: don't change to std Created 4 years, 6 months ago

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Index: base/strings/string_number_conversions_unittest.cc

diff --git a/base/strings/string_number_conversions_unittest.cc b/base/strings/string_number_conversions_unittest.cc

index 0cc71a696b443eaedebfae72750edb1152cd4d2d..53f1ce1bab91bd05b27ab6ee2cbc1139dbe2dd31 100644

--- a/base/strings/string_number_conversions_unittest.cc

+++ b/base/strings/string_number_conversions_unittest.cc

@@ -805,4 +805,234 @@ TEST(StringNumberConversionsTest, HexEncode) {

EXPECT_EQ(hex.compare("01FF02FE038081"), 0);

}

+// http://www.exploringbinary.com/converting-floating-point-numbers-to-binary-strings-in-c/

Nico 2016/06/08 00:45:09 that doesn't say anything about license or "ok to

scottmg 2016/06/08 02:28:18 Hmm, true. I'll see if I can find something simila

+// by Rick Regan.

+std::string FpToBin(double fp) {

+ double fp_int;

+ double fp_frac = modf(fp, &fp_int);

+ std::string result;

+ if (fp_int != 0) {

+ std::string integral;

+ do {

+ integral += '0' + static_cast<int>(fmod(fp_int, 2));

+ fp_int = floor(fp_int / 2);

+ } while (fp_int > 0);

+ std::reverse(integral.begin(), integral.end());

+ result += integral;

+ } else {

+ result += "0";

+ }

+ result += ".";

+ if (fp_frac != 0) {

+ std::string fractional;

+ while (fp_frac > 0) {

+ fp_frac *= 2;

+ double integral_part;

+ fp_frac = modf(fp_frac, &integral_part);

+ fractional += '0' + static_cast<int>(integral_part);

+ }

+ result += fractional;

+ } else {

+ result += "0";

+ }

+ return result;

+TEST(StringNumberConversionsTest, TestFpToBin) {

+ EXPECT_EQ(FpToBin(16), "10000.0");

+ EXPECT_EQ(FpToBin(0.00390625), "0.00000001");

+ EXPECT_EQ(FpToBin(25), "11001.0");

+ EXPECT_EQ(FpToBin(0.1),

+ "0.0001100110011001100110011001100110011001100110011001101");

+ EXPECT_EQ(FpToBin(0.6),

+ "0.10011001100110011001100110011001100110011001100110011");

+// Test cases of known-bad strtod conversions that motivated the use of dmg_fp.

+// See https://bugs.chromium.org/p/chromium/issues/detail?id=593512.

+TEST(StringNumberConversionsTest, StrtodFailures) {

+ static const struct {

+ const char* input;

+ const char* expected;

+ } cases[] = {

+ // http://www.exploringbinary.com/incorrectly-rounded-conversions-in-visual-c-plus-plus/

+ {"9214843084008499",

+ "100000101111001101100111011000101011101110110000110100.0"},

Nico 2016/06/08 00:45:09 could we use hexfloats for the expecteds instead?

scottmg 2016/06/08 02:28:18 VS doesn't seem to support hex floating point lite

scottmg 2016/06/08 02:36:04 No such luck. d:\src\x>type fp.c #include <stdio.

+ {"0.500000000000000166533453693773481063544750213623046875",

+ "0.1000000000000000000000000000000000000000000000000001"},

+ {"30078505129381147446200",

+ "1100101111010001111000111001001110001101100000010000100000000000000"

+ "00000000.0"},

+ {"1777820000000000000001",

+ "1100000011000000011010101101110101101001011100011111000000000000000"

+ "0000.0"},

+ {"0."

+ "500000000000000166547006220929549868969843373633921146392822265625",

+ "0.1000000000000000000000000000000000000000000000000001"},

+ {"0."

+ "50000000000000016656055874808561867439493653364479541778564453125",

+ "0.1000000000000000000000000000000000000000000000000001"},

+ {"0.3932922657273",

+ "0.01100100101011101100110101001011000100011000100011101"},

+ // http://www.exploringbinary.com/incorrectly-rounded-conversions-in-gcc-and-glibc/

+ {"0.500000000000000166533453693773481063544750213623046875",

+ "0.1000000000000000000000000000000000000000000000000001"},

+ {"3.518437208883201171875e13",

+ "1000000000000000000000000000000000000000000000.000001"},

+ {"62.5364939768271845828",

+ "111110.100010010101011110101011010101001111100101001"},

+ {"8.10109172351e-10",

+ "0."

+ "0000000000000000000000000000001101111010101110010111010111011110000"

+ "11111101000011"},

+ {"1.50000000000000011102230246251565404236316680908203125", "1.1"},

+ {"9007199254740991.4999999999999999999999999999999995",

+ "11111111111111111111111111111111111111111111111111111.0"},

+ // http://www.exploringbinary.com/incorrect-decimal-to-floating-point-conversion-in-sqlite/

+ {"1e-23",

+ /* 0x1.82db34012b251p-77 */ "0."

+ "0000000000000000000000000000000000000000000"

+ "0000000000000000000000000000000001100000101"

+ "101101100110100000000010010101100100101000"

+ "1"},

+ {"8.533e+68",

+ /* 0x1.fa69165a8eea2p+228 */ "111111010011010010001011001011010100011101"

+ "110101000100000000000000000000000000000000"

+ "000000000000000000000000000000000000000000"

+ "0000000000000000000.0"},

+ {"4.1006e-184",

+ /* 0x1.be0d1c7ea60c9p-610 */ "0."

+ "000000000000000000000000000000000000000000"

+ "000000000000000000000110111110000011010001"

+ "11000111111010100110000011001001"},

+ {"9.998e+307",

+ /* 0x1.1cc0a350ca87bp+1023 */ "10001110011000000101000110101000011001010"

+ "10000111101100000000000000000000000000000"

+ "00000000000000000000000000000000000000000"

+ "0000000000000000000000000000000000000000."

+ "0"},

+ {"9.9538452227e-280",

+ /* 0x1.2117ae45cde43p-927 */ "0."

+ "000000000000000000000000000000000000000000"

+ "001001000010001011110101110010001011100110"

+ "1111001000011"},

+ {"6.47660115e-260",

+ /* 0x1.fdd9e333badadp-862 */ "0."

+ "000000000000000000000000000000000000000000"

+ "000000000000000000000111111101110110011110"

+ "00110011001110111010110110101101"},

+ {"7.4e+47",

+ /* 0x1.033d7eca0adefp+159 */ "100000011001111010111111011001010000010101"

+ "101111011110000000000000000000000000000000"

+ "000000000000000000000000000000000000000000"

+ "0000000000000000000000000000000000.0"},

+ {"5.92e+48",

+ /* 0x1.033d7eca0adefp+162 */ "100000011001111010111111011001010000010101"

+ "101111011110000000000000000000000000000000"

+ "000000000000000000000000000000000000000000"

+ "0000000000000000000000000000000000000.0"},

+ {"7.35e+66",

+ /* 0x1.172b70eababa9p+222 */ "100010111001010110111000011101010101110101"

+ "011101010010000000000000000000000000000000"

+ "000000000000000000000000000000000000000000"

+ "0000000000000.0"},

+ {"8.32116e+55",

+ /* 0x1.b2628393e02cdp+185 */ "110110010011000101000001110010011111000000"

+ "010110011010000000000000000000000000000000"

+ "000000000000000000000000000000000000000000"

+ "000000000000000000.0"},

+ };

+ for (const auto& test : cases) {

+ double output;

+ EXPECT_TRUE(StringToDouble(test.input, &output));

+ EXPECT_EQ(FpToBin(output), test.expected);

+ }

} // namespace base

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