diff options
Diffstat (limited to 'absl/strings/internal/str_format/convert_test.cc')
| -rw-r--r-- | absl/strings/internal/str_format/convert_test.cc | 671 |
1 files changed, 624 insertions, 47 deletions
diff --git a/absl/strings/internal/str_format/convert_test.cc b/absl/strings/internal/str_format/convert_test.cc index cbcd7caf..634ee78b 100644 --- a/absl/strings/internal/str_format/convert_test.cc +++ b/absl/strings/internal/str_format/convert_test.cc @@ -1,20 +1,32 @@ #include <errno.h> #include <stdarg.h> #include <stdio.h> + #include <cctype> #include <cmath> +#include <limits> #include <string> +#include <thread> // NOLINT #include "gmock/gmock.h" #include "gtest/gtest.h" #include "absl/base/internal/raw_logging.h" #include "absl/strings/internal/str_format/bind.h" +#include "absl/strings/match.h" +#include "absl/types/optional.h" namespace absl { ABSL_NAMESPACE_BEGIN namespace str_format_internal { namespace { +struct NativePrintfTraits { + bool hex_float_has_glibc_rounding; + bool hex_float_prefers_denormal_repr; + bool hex_float_uses_minimal_precision_when_not_specified; + bool hex_float_optimizes_leading_digit_bit_count; +}; + template <typename T, size_t N> size_t ArraySize(T (&)[N]) { return N; @@ -57,7 +69,7 @@ std::string Esc(const T &v) { return oss.str(); } -void StrAppend(std::string *dst, const char *format, va_list ap) { +void StrAppendV(std::string *dst, const char *format, va_list ap) { // First try with a small fixed size buffer static const int kSpaceLength = 1024; char space[kSpaceLength]; @@ -98,15 +110,79 @@ void StrAppend(std::string *dst, const char *format, va_list ap) { delete[] buf; } +void StrAppend(std::string *out, const char *format, ...) { + va_list ap; + va_start(ap, format); + StrAppendV(out, format, ap); + va_end(ap); +} + std::string StrPrint(const char *format, ...) { va_list ap; va_start(ap, format); std::string result; - StrAppend(&result, format, ap); + StrAppendV(&result, format, ap); va_end(ap); return result; } +NativePrintfTraits VerifyNativeImplementationImpl() { + NativePrintfTraits result; + + // >>> hex_float_has_glibc_rounding. To have glibc's rounding behavior we need + // to meet three requirements: + // + // - The threshold for rounding up is 8 (for e.g. MSVC uses 9). + // - If the digits lower than than the 8 are non-zero then we round up. + // - If the digits lower than the 8 are all zero then we round toward even. + // + // The numbers below represent all the cases covering {below,at,above} the + // threshold (8) with both {zero,non-zero} lower bits and both {even,odd} + // preceding digits. + const double d0079 = 65657.0; // 0x1.0079p+16 + const double d0179 = 65913.0; // 0x1.0179p+16 + const double d0080 = 65664.0; // 0x1.0080p+16 + const double d0180 = 65920.0; // 0x1.0180p+16 + const double d0081 = 65665.0; // 0x1.0081p+16 + const double d0181 = 65921.0; // 0x1.0181p+16 + result.hex_float_has_glibc_rounding = + StartsWith(StrPrint("%.2a", d0079), "0x1.00") && + StartsWith(StrPrint("%.2a", d0179), "0x1.01") && + StartsWith(StrPrint("%.2a", d0080), "0x1.00") && + StartsWith(StrPrint("%.2a", d0180), "0x1.02") && + StartsWith(StrPrint("%.2a", d0081), "0x1.01") && + StartsWith(StrPrint("%.2a", d0181), "0x1.02"); + + // >>> hex_float_prefers_denormal_repr. Formatting `denormal` on glibc yields + // "0x0.0000000000001p-1022", whereas on std libs that don't use denormal + // representation it would either be 0x1p-1074 or 0x1.0000000000000-1074. + const double denormal = std::numeric_limits<double>::denorm_min(); + result.hex_float_prefers_denormal_repr = + StartsWith(StrPrint("%a", denormal), "0x0.0000000000001"); + + // >>> hex_float_uses_minimal_precision_when_not_specified. Some (non-glibc) + // libs will format the following as "0x1.0079000000000p+16". + result.hex_float_uses_minimal_precision_when_not_specified = + (StrPrint("%a", d0079) == "0x1.0079p+16"); + + // >>> hex_float_optimizes_leading_digit_bit_count. The number 1.5, when + // formatted by glibc should yield "0x1.8p+0" for `double` and "0xcp-3" for + // `long double`, i.e., number of bits in the leading digit is adapted to the + // number of bits in the mantissa. + const double d_15 = 1.5; + const long double ld_15 = 1.5; + result.hex_float_optimizes_leading_digit_bit_count = + StartsWith(StrPrint("%a", d_15), "0x1.8") && + StartsWith(StrPrint("%La", ld_15), "0xc"); + + return result; +} + +const NativePrintfTraits &VerifyNativeImplementation() { + static NativePrintfTraits native_traits = VerifyNativeImplementationImpl(); + return native_traits; +} + class FormatConvertTest : public ::testing::Test { }; template <typename T> @@ -463,6 +539,68 @@ TEST_F(FormatConvertTest, Uint128) { } } +template <typename Floating> +void TestWithMultipleFormatsHelper(const std::vector<Floating> &floats) { + const NativePrintfTraits &native_traits = VerifyNativeImplementation(); + // Reserve the space to ensure we don't allocate memory in the output itself. + std::string str_format_result; + str_format_result.reserve(1 << 20); + std::string string_printf_result; + string_printf_result.reserve(1 << 20); + + const char *const kFormats[] = { + "%", "%.3", "%8.5", "%500", "%.5000", "%.60", "%.30", "%03", + "%+", "% ", "%-10", "%#15.3", "%#.0", "%.0", "%1$*2$", "%1$.*2$"}; + + for (const char *fmt : kFormats) { + for (char f : {'f', 'F', // + 'g', 'G', // + 'a', 'A', // + 'e', 'E'}) { + std::string fmt_str = std::string(fmt) + f; + + if (fmt == absl::string_view("%.5000") && f != 'f' && f != 'F' && + f != 'a' && f != 'A') { + // This particular test takes way too long with snprintf. + // Disable for the case we are not implementing natively. + continue; + } + + if ((f == 'a' || f == 'A') && + !native_traits.hex_float_has_glibc_rounding) { + continue; + } + + for (Floating d : floats) { + if (!native_traits.hex_float_prefers_denormal_repr && + (f == 'a' || f == 'A') && std::fpclassify(d) == FP_SUBNORMAL) { + continue; + } + int i = -10; + FormatArgImpl args[2] = {FormatArgImpl(d), FormatArgImpl(i)}; + UntypedFormatSpecImpl format(fmt_str); + + string_printf_result.clear(); + StrAppend(&string_printf_result, fmt_str.c_str(), d, i); + str_format_result.clear(); + + { + AppendPack(&str_format_result, format, absl::MakeSpan(args)); + } + + if (string_printf_result != str_format_result) { + // We use ASSERT_EQ here because failures are usually correlated and a + // bug would print way too many failed expectations causing the test + // to time out. + ASSERT_EQ(string_printf_result, str_format_result) + << fmt_str << " " << StrPrint("%.18g", d) << " " + << StrPrint("%a", d) << " " << StrPrint("%.50f", d); + } + } + } + } +} + TEST_F(FormatConvertTest, Float) { #ifdef _MSC_VER // MSVC has a different rounding policy than us so we can't test our @@ -470,9 +608,62 @@ TEST_F(FormatConvertTest, Float) { return; #endif // _MSC_VER - const char *const kFormats[] = { - "%", "%.3", "%8.5", "%9", "%.60", "%.30", "%03", "%+", - "% ", "%-10", "%#15.3", "%#.0", "%.0", "%1$*2$", "%1$.*2$"}; + std::vector<float> floats = {0.0f, + -0.0f, + .9999999f, + 9999999.f, + std::numeric_limits<float>::max(), + -std::numeric_limits<float>::max(), + std::numeric_limits<float>::min(), + -std::numeric_limits<float>::min(), + std::numeric_limits<float>::lowest(), + -std::numeric_limits<float>::lowest(), + std::numeric_limits<float>::epsilon(), + std::numeric_limits<float>::epsilon() + 1.0f, + std::numeric_limits<float>::infinity(), + -std::numeric_limits<float>::infinity()}; + + // Some regression tests. + floats.push_back(0.999999989f); + + if (std::numeric_limits<float>::has_denorm != std::denorm_absent) { + floats.push_back(std::numeric_limits<float>::denorm_min()); + floats.push_back(-std::numeric_limits<float>::denorm_min()); + } + + for (float base : + {1.f, 12.f, 123.f, 1234.f, 12345.f, 123456.f, 1234567.f, 12345678.f, + 123456789.f, 1234567890.f, 12345678901.f, 12345678.f, 12345678.f}) { + for (int exp = -123; exp <= 123; ++exp) { + for (int sign : {1, -1}) { + floats.push_back(sign * std::ldexp(base, exp)); + } + } + } + + for (int exp = -300; exp <= 300; ++exp) { + const float all_ones_mantissa = 0xffffff; + floats.push_back(std::ldexp(all_ones_mantissa, exp)); + } + + // Remove duplicates to speed up the logic below. + std::sort(floats.begin(), floats.end()); + floats.erase(std::unique(floats.begin(), floats.end()), floats.end()); + +#ifndef __APPLE__ + // Apple formats NaN differently (+nan) vs. (nan) + floats.push_back(std::nan("")); +#endif + + TestWithMultipleFormatsHelper(floats); +} + +TEST_F(FormatConvertTest, Double) { +#ifdef _MSC_VER + // MSVC has a different rounding policy than us so we can't test our + // implementation against the native one there. + return; +#endif // _MSC_VER std::vector<double> doubles = {0.0, -0.0, @@ -489,11 +680,6 @@ TEST_F(FormatConvertTest, Float) { std::numeric_limits<double>::infinity(), -std::numeric_limits<double>::infinity()}; -#ifndef __APPLE__ - // Apple formats NaN differently (+nan) vs. (nan) - doubles.push_back(std::nan("")); -#endif - // Some regression tests. doubles.push_back(0.99999999999999989); @@ -512,43 +698,375 @@ TEST_F(FormatConvertTest, Float) { } } - for (const char *fmt : kFormats) { - for (char f : {'f', 'F', // - 'g', 'G', // - 'a', 'A', // - 'e', 'E'}) { - std::string fmt_str = std::string(fmt) + f; - for (double d : doubles) { - int i = -10; - FormatArgImpl args[2] = {FormatArgImpl(d), FormatArgImpl(i)}; - UntypedFormatSpecImpl format(fmt_str); - // We use ASSERT_EQ here because failures are usually correlated and a - // bug would print way too many failed expectations causing the test to - // time out. - ASSERT_EQ(StrPrint(fmt_str.c_str(), d, i), - FormatPack(format, absl::MakeSpan(args))) - << fmt_str << " " << StrPrint("%.18g", d) << " " - << StrPrint("%.999f", d); + // Workaround libc bug. + // https://sourceware.org/bugzilla/show_bug.cgi?id=22142 + const bool gcc_bug_22142 = + StrPrint("%f", std::numeric_limits<double>::max()) != + "1797693134862315708145274237317043567980705675258449965989174768031" + "5726078002853876058955863276687817154045895351438246423432132688946" + "4182768467546703537516986049910576551282076245490090389328944075868" + "5084551339423045832369032229481658085593321233482747978262041447231" + "68738177180919299881250404026184124858368.000000"; + + if (!gcc_bug_22142) { + for (int exp = -300; exp <= 300; ++exp) { + const double all_ones_mantissa = 0x1fffffffffffff; + doubles.push_back(std::ldexp(all_ones_mantissa, exp)); + } + } + + if (gcc_bug_22142) { + for (auto &d : doubles) { + using L = std::numeric_limits<double>; + double d2 = std::abs(d); + if (d2 == L::max() || d2 == L::min() || d2 == L::denorm_min()) { + d = 0; } } } + + // Remove duplicates to speed up the logic below. + std::sort(doubles.begin(), doubles.end()); + doubles.erase(std::unique(doubles.begin(), doubles.end()), doubles.end()); + +#ifndef __APPLE__ + // Apple formats NaN differently (+nan) vs. (nan) + doubles.push_back(std::nan("")); +#endif + + TestWithMultipleFormatsHelper(doubles); +} + +TEST_F(FormatConvertTest, DoubleRound) { + std::string s; + const auto format = [&](const char *fmt, double d) -> std::string & { + s.clear(); + FormatArgImpl args[1] = {FormatArgImpl(d)}; + AppendPack(&s, UntypedFormatSpecImpl(fmt), absl::MakeSpan(args)); +#if !defined(_MSC_VER) + // MSVC has a different rounding policy than us so we can't test our + // implementation against the native one there. + EXPECT_EQ(StrPrint(fmt, d), s); +#endif // _MSC_VER + + return s; + }; + // All of these values have to be exactly represented. + // Otherwise we might not be testing what we think we are testing. + + // These values can fit in a 64bit "fast" representation. + const double exact_value = 0.00000000000005684341886080801486968994140625; + assert(exact_value == std::pow(2, -44)); + // Round up at a 5xx. + EXPECT_EQ(format("%.13f", exact_value), "0.0000000000001"); + // Round up at a >5 + EXPECT_EQ(format("%.14f", exact_value), "0.00000000000006"); + // Round down at a <5 + EXPECT_EQ(format("%.16f", exact_value), "0.0000000000000568"); + // Nine handling + EXPECT_EQ(format("%.35f", exact_value), + "0.00000000000005684341886080801486969"); + EXPECT_EQ(format("%.36f", exact_value), + "0.000000000000056843418860808014869690"); + // Round down the last nine. + EXPECT_EQ(format("%.37f", exact_value), + "0.0000000000000568434188608080148696899"); + EXPECT_EQ(format("%.10f", 0.000003814697265625), "0.0000038147"); + // Round up the last nine + EXPECT_EQ(format("%.11f", 0.000003814697265625), "0.00000381470"); + EXPECT_EQ(format("%.12f", 0.000003814697265625), "0.000003814697"); + + // Round to even (down) + EXPECT_EQ(format("%.43f", exact_value), + "0.0000000000000568434188608080148696899414062"); + // Exact + EXPECT_EQ(format("%.44f", exact_value), + "0.00000000000005684341886080801486968994140625"); + // Round to even (up), let make the last digits 75 instead of 25 + EXPECT_EQ(format("%.43f", exact_value + std::pow(2, -43)), + "0.0000000000001705302565824240446090698242188"); + // Exact, just to check. + EXPECT_EQ(format("%.44f", exact_value + std::pow(2, -43)), + "0.00000000000017053025658242404460906982421875"); + + // This value has to be small enough that it won't fit in the uint128 + // representation for printing. + const double small_exact_value = + 0.000000000000000000000000000000000000752316384526264005099991383822237233803945956334136013765601092018187046051025390625; // NOLINT + assert(small_exact_value == std::pow(2, -120)); + // Round up at a 5xx. + EXPECT_EQ(format("%.37f", small_exact_value), + "0.0000000000000000000000000000000000008"); + // Round down at a <5 + EXPECT_EQ(format("%.38f", small_exact_value), + "0.00000000000000000000000000000000000075"); + // Round up at a >5 + EXPECT_EQ(format("%.41f", small_exact_value), + "0.00000000000000000000000000000000000075232"); + // Nine handling + EXPECT_EQ(format("%.55f", small_exact_value), + "0.0000000000000000000000000000000000007523163845262640051"); + EXPECT_EQ(format("%.56f", small_exact_value), + "0.00000000000000000000000000000000000075231638452626400510"); + EXPECT_EQ(format("%.57f", small_exact_value), + "0.000000000000000000000000000000000000752316384526264005100"); + EXPECT_EQ(format("%.58f", small_exact_value), + "0.0000000000000000000000000000000000007523163845262640051000"); + // Round down the last nine + EXPECT_EQ(format("%.59f", small_exact_value), + "0.00000000000000000000000000000000000075231638452626400509999"); + // Round up the last nine + EXPECT_EQ(format("%.79f", small_exact_value), + "0.000000000000000000000000000000000000" + "7523163845262640050999913838222372338039460"); + + // Round to even (down) + EXPECT_EQ(format("%.119f", small_exact_value), + "0.000000000000000000000000000000000000" + "75231638452626400509999138382223723380" + "394595633413601376560109201818704605102539062"); + // Exact + EXPECT_EQ(format("%.120f", small_exact_value), + "0.000000000000000000000000000000000000" + "75231638452626400509999138382223723380" + "3945956334136013765601092018187046051025390625"); + // Round to even (up), let make the last digits 75 instead of 25 + EXPECT_EQ(format("%.119f", small_exact_value + std::pow(2, -119)), + "0.000000000000000000000000000000000002" + "25694915357879201529997415146671170141" + "183786900240804129680327605456113815307617188"); + // Exact, just to check. + EXPECT_EQ(format("%.120f", small_exact_value + std::pow(2, -119)), + "0.000000000000000000000000000000000002" + "25694915357879201529997415146671170141" + "1837869002408041296803276054561138153076171875"); +} + +TEST_F(FormatConvertTest, DoubleRoundA) { + const NativePrintfTraits &native_traits = VerifyNativeImplementation(); + std::string s; + const auto format = [&](const char *fmt, double d) -> std::string & { + s.clear(); + FormatArgImpl args[1] = {FormatArgImpl(d)}; + AppendPack(&s, UntypedFormatSpecImpl(fmt), absl::MakeSpan(args)); + if (native_traits.hex_float_has_glibc_rounding) { + EXPECT_EQ(StrPrint(fmt, d), s); + } + return s; + }; + + // 0x1.00018000p+100 + const double on_boundary_odd = 1267679614447900152596896153600.0; + EXPECT_EQ(format("%.0a", on_boundary_odd), "0x1p+100"); + EXPECT_EQ(format("%.1a", on_boundary_odd), "0x1.0p+100"); + EXPECT_EQ(format("%.2a", on_boundary_odd), "0x1.00p+100"); + EXPECT_EQ(format("%.3a", on_boundary_odd), "0x1.000p+100"); + EXPECT_EQ(format("%.4a", on_boundary_odd), "0x1.0002p+100"); // round + EXPECT_EQ(format("%.5a", on_boundary_odd), "0x1.00018p+100"); + EXPECT_EQ(format("%.6a", on_boundary_odd), "0x1.000180p+100"); + + // 0x1.00028000p-2 + const double on_boundary_even = 0.250009536743164062500; + EXPECT_EQ(format("%.0a", on_boundary_even), "0x1p-2"); + EXPECT_EQ(format("%.1a", on_boundary_even), "0x1.0p-2"); + EXPECT_EQ(format("%.2a", on_boundary_even), "0x1.00p-2"); + EXPECT_EQ(format("%.3a", on_boundary_even), "0x1.000p-2"); + EXPECT_EQ(format("%.4a", on_boundary_even), "0x1.0002p-2"); // no round + EXPECT_EQ(format("%.5a", on_boundary_even), "0x1.00028p-2"); + EXPECT_EQ(format("%.6a", on_boundary_even), "0x1.000280p-2"); + + // 0x1.00018001p+1 + const double slightly_over = 2.00004577683284878730773925781250; + EXPECT_EQ(format("%.0a", slightly_over), "0x1p+1"); + EXPECT_EQ(format("%.1a", slightly_over), "0x1.0p+1"); + EXPECT_EQ(format("%.2a", slightly_over), "0x1.00p+1"); + EXPECT_EQ(format("%.3a", slightly_over), "0x1.000p+1"); + EXPECT_EQ(format("%.4a", slightly_over), "0x1.0002p+1"); + EXPECT_EQ(format("%.5a", slightly_over), "0x1.00018p+1"); + EXPECT_EQ(format("%.6a", slightly_over), "0x1.000180p+1"); + + // 0x1.00017fffp+0 + const double slightly_under = 1.000022887950763106346130371093750; + EXPECT_EQ(format("%.0a", slightly_under), "0x1p+0"); + EXPECT_EQ(format("%.1a", slightly_under), "0x1.0p+0"); + EXPECT_EQ(format("%.2a", slightly_under), "0x1.00p+0"); + EXPECT_EQ(format("%.3a", slightly_under), "0x1.000p+0"); + EXPECT_EQ(format("%.4a", slightly_under), "0x1.0001p+0"); + EXPECT_EQ(format("%.5a", slightly_under), "0x1.00018p+0"); + EXPECT_EQ(format("%.6a", slightly_under), "0x1.000180p+0"); + EXPECT_EQ(format("%.7a", slightly_under), "0x1.0001800p+0"); + + // 0x1.1b3829ac28058p+3 + const double hex_value = 8.85060580848964661981881363317370414733886718750; + EXPECT_EQ(format("%.0a", hex_value), "0x1p+3"); + EXPECT_EQ(format("%.1a", hex_value), "0x1.2p+3"); + EXPECT_EQ(format("%.2a", hex_value), "0x1.1bp+3"); + EXPECT_EQ(format("%.3a", hex_value), "0x1.1b4p+3"); + EXPECT_EQ(format("%.4a", hex_value), "0x1.1b38p+3"); + EXPECT_EQ(format("%.5a", hex_value), "0x1.1b383p+3"); + EXPECT_EQ(format("%.6a", hex_value), "0x1.1b382ap+3"); + EXPECT_EQ(format("%.7a", hex_value), "0x1.1b3829bp+3"); + EXPECT_EQ(format("%.8a", hex_value), "0x1.1b3829acp+3"); + EXPECT_EQ(format("%.9a", hex_value), "0x1.1b3829ac3p+3"); + EXPECT_EQ(format("%.10a", hex_value), "0x1.1b3829ac28p+3"); + EXPECT_EQ(format("%.11a", hex_value), "0x1.1b3829ac280p+3"); + EXPECT_EQ(format("%.12a", hex_value), "0x1.1b3829ac2806p+3"); + EXPECT_EQ(format("%.13a", hex_value), "0x1.1b3829ac28058p+3"); + EXPECT_EQ(format("%.14a", hex_value), "0x1.1b3829ac280580p+3"); + EXPECT_EQ(format("%.15a", hex_value), "0x1.1b3829ac2805800p+3"); + EXPECT_EQ(format("%.16a", hex_value), "0x1.1b3829ac28058000p+3"); + EXPECT_EQ(format("%.17a", hex_value), "0x1.1b3829ac280580000p+3"); + EXPECT_EQ(format("%.18a", hex_value), "0x1.1b3829ac2805800000p+3"); + EXPECT_EQ(format("%.19a", hex_value), "0x1.1b3829ac28058000000p+3"); + EXPECT_EQ(format("%.20a", hex_value), "0x1.1b3829ac280580000000p+3"); + EXPECT_EQ(format("%.21a", hex_value), "0x1.1b3829ac2805800000000p+3"); + + // 0x1.0818283848586p+3 + const double hex_value2 = 8.2529488658208371987257123691961169242858886718750; + EXPECT_EQ(format("%.0a", hex_value2), "0x1p+3"); + EXPECT_EQ(format("%.1a", hex_value2), "0x1.1p+3"); + EXPECT_EQ(format("%.2a", hex_value2), "0x1.08p+3"); + EXPECT_EQ(format("%.3a", hex_value2), "0x1.082p+3"); + EXPECT_EQ(format("%.4a", hex_value2), "0x1.0818p+3"); + EXPECT_EQ(format("%.5a", hex_value2), "0x1.08183p+3"); + EXPECT_EQ(format("%.6a", hex_value2), "0x1.081828p+3"); + EXPECT_EQ(format("%.7a", hex_value2), "0x1.0818284p+3"); + EXPECT_EQ(format("%.8a", hex_value2), "0x1.08182838p+3"); + EXPECT_EQ(format("%.9a", hex_value2), "0x1.081828385p+3"); + EXPECT_EQ(format("%.10a", hex_value2), "0x1.0818283848p+3"); + EXPECT_EQ(format("%.11a", hex_value2), "0x1.08182838486p+3"); + EXPECT_EQ(format("%.12a", hex_value2), "0x1.081828384858p+3"); + EXPECT_EQ(format("%.13a", hex_value2), "0x1.0818283848586p+3"); + EXPECT_EQ(format("%.14a", hex_value2), "0x1.08182838485860p+3"); + EXPECT_EQ(format("%.15a", hex_value2), "0x1.081828384858600p+3"); + EXPECT_EQ(format("%.16a", hex_value2), "0x1.0818283848586000p+3"); + EXPECT_EQ(format("%.17a", hex_value2), "0x1.08182838485860000p+3"); + EXPECT_EQ(format("%.18a", hex_value2), "0x1.081828384858600000p+3"); + EXPECT_EQ(format("%.19a", hex_value2), "0x1.0818283848586000000p+3"); + EXPECT_EQ(format("%.20a", hex_value2), "0x1.08182838485860000000p+3"); + EXPECT_EQ(format("%.21a", hex_value2), "0x1.081828384858600000000p+3"); +} + +TEST_F(FormatConvertTest, LongDoubleRoundA) { + if (std::numeric_limits<long double>::digits % 4 != 0) { + // This test doesn't really make sense to run on platforms where a long + // double has a different mantissa size (mod 4) than Prod, since then the + // leading digit will be formatted differently. + return; + } + const NativePrintfTraits &native_traits = VerifyNativeImplementation(); + std::string s; + const auto format = [&](const char *fmt, long double d) -> std::string & { + s.clear(); + FormatArgImpl args[1] = {FormatArgImpl(d)}; + AppendPack(&s, UntypedFormatSpecImpl(fmt), absl::MakeSpan(args)); + if (native_traits.hex_float_has_glibc_rounding && + native_traits.hex_float_optimizes_leading_digit_bit_count) { + EXPECT_EQ(StrPrint(fmt, d), s); + } + return s; + }; + + // 0x8.8p+4 + const long double on_boundary_even = 136.0; + EXPECT_EQ(format("%.0La", on_boundary_even), "0x8p+4"); + EXPECT_EQ(format("%.1La", on_boundary_even), "0x8.8p+4"); + EXPECT_EQ(format("%.2La", on_boundary_even), "0x8.80p+4"); + EXPECT_EQ(format("%.3La", on_boundary_even), "0x8.800p+4"); + EXPECT_EQ(format("%.4La", on_boundary_even), "0x8.8000p+4"); + EXPECT_EQ(format("%.5La", on_boundary_even), "0x8.80000p+4"); + EXPECT_EQ(format("%.6La", on_boundary_even), "0x8.800000p+4"); + + // 0x9.8p+4 + const long double on_boundary_odd = 152.0; + EXPECT_EQ(format("%.0La", on_boundary_odd), "0xap+4"); + EXPECT_EQ(format("%.1La", on_boundary_odd), "0x9.8p+4"); + EXPECT_EQ(format("%.2La", on_boundary_odd), "0x9.80p+4"); + EXPECT_EQ(format("%.3La", on_boundary_odd), "0x9.800p+4"); + EXPECT_EQ(format("%.4La", on_boundary_odd), "0x9.8000p+4"); + EXPECT_EQ(format("%.5La", on_boundary_odd), "0x9.80000p+4"); + EXPECT_EQ(format("%.6La", on_boundary_odd), "0x9.800000p+4"); + + // 0x8.80001p+24 + const long double slightly_over = 142606352.0; + EXPECT_EQ(format("%.0La", slightly_over), "0x9p+24"); + EXPECT_EQ(format("%.1La", slightly_over), "0x8.8p+24"); + EXPECT_EQ(format("%.2La", slightly_over), "0x8.80p+24"); + EXPECT_EQ(format("%.3La", slightly_over), "0x8.800p+24"); + EXPECT_EQ(format("%.4La", slightly_over), "0x8.8000p+24"); + EXPECT_EQ(format("%.5La", slightly_over), "0x8.80001p+24"); + EXPECT_EQ(format("%.6La", slightly_over), "0x8.800010p+24"); + + // 0x8.7ffffp+24 + const long double slightly_under = 142606320.0; + EXPECT_EQ(format("%.0La", slightly_under), "0x8p+24"); + EXPECT_EQ(format("%.1La", slightly_under), "0x8.8p+24"); + EXPECT_EQ(format("%.2La", slightly_under), "0x8.80p+24"); + EXPECT_EQ(format("%.3La", slightly_under), "0x8.800p+24"); + EXPECT_EQ(format("%.4La", slightly_under), "0x8.8000p+24"); + EXPECT_EQ(format("%.5La", slightly_under), "0x8.7ffffp+24"); + EXPECT_EQ(format("%.6La", slightly_under), "0x8.7ffff0p+24"); + EXPECT_EQ(format("%.7La", slightly_under), "0x8.7ffff00p+24"); + + // 0xc.0828384858688000p+128 + const long double eights = 4094231060438608800781871108094404067328.0; + EXPECT_EQ(format("%.0La", eights), "0xcp+128"); + EXPECT_EQ(format("%.1La", eights), "0xc.1p+128"); + EXPECT_EQ(format("%.2La", eights), "0xc.08p+128"); + EXPECT_EQ(format("%.3La", eights), "0xc.083p+128"); + EXPECT_EQ(format("%.4La", eights), "0xc.0828p+128"); + EXPECT_EQ(format("%.5La", eights), "0xc.08284p+128"); + EXPECT_EQ(format("%.6La", eights), "0xc.082838p+128"); + EXPECT_EQ(format("%.7La", eights), "0xc.0828385p+128"); + EXPECT_EQ(format("%.8La", eights), "0xc.08283848p+128"); + EXPECT_EQ(format("%.9La", eights), "0xc.082838486p+128"); + EXPECT_EQ(format("%.10La", eights), "0xc.0828384858p+128"); + EXPECT_EQ(format("%.11La", eights), "0xc.08283848587p+128"); + EXPECT_EQ(format("%.12La", eights), "0xc.082838485868p+128"); + EXPECT_EQ(format("%.13La", eights), "0xc.0828384858688p+128"); + EXPECT_EQ(format("%.14La", eights), "0xc.08283848586880p+128"); + EXPECT_EQ(format("%.15La", eights), "0xc.082838485868800p+128"); + EXPECT_EQ(format("%.16La", eights), "0xc.0828384858688000p+128"); +} + +// We don't actually store the results. This is just to exercise the rest of the +// machinery. +struct NullSink { + friend void AbslFormatFlush(NullSink *sink, string_view str) {} +}; + +template <typename... T> +bool FormatWithNullSink(absl::string_view fmt, const T &... a) { + NullSink sink; + FormatArgImpl args[] = {FormatArgImpl(a)...}; + return FormatUntyped(&sink, UntypedFormatSpecImpl(fmt), absl::MakeSpan(args)); +} + +TEST_F(FormatConvertTest, ExtremeWidthPrecision) { + for (const char *fmt : {"f"}) { + for (double d : {1e-100, 1.0, 1e100}) { + constexpr int max = std::numeric_limits<int>::max(); + EXPECT_TRUE(FormatWithNullSink(std::string("%.*") + fmt, max, d)); + EXPECT_TRUE(FormatWithNullSink(std::string("%1.*") + fmt, max, d)); + EXPECT_TRUE(FormatWithNullSink(std::string("%*") + fmt, max, d)); + EXPECT_TRUE(FormatWithNullSink(std::string("%*.*") + fmt, max, max, d)); + } + } } TEST_F(FormatConvertTest, LongDouble) { - const char *const kFormats[] = {"%", "%.3", "%8.5", "%9", +#ifdef _MSC_VER + // MSVC has a different rounding policy than us so we can't test our + // implementation against the native one there. + return; +#endif // _MSC_VER + const NativePrintfTraits &native_traits = VerifyNativeImplementation(); + const char *const kFormats[] = {"%", "%.3", "%8.5", "%9", "%.5000", "%.60", "%+", "% ", "%-10"}; - // This value is not representable in double, but it is in long double that - // uses the extended format. - // This is to verify that we are not truncating the value mistakenly through a - // double. - long double very_precise = 10000000000000000.25L; - std::vector<long double> doubles = { 0.0, -0.0, - very_precise, - 1 / very_precise, std::numeric_limits<long double>::max(), -std::numeric_limits<long double>::max(), std::numeric_limits<long double>::min(), @@ -556,28 +1074,65 @@ TEST_F(FormatConvertTest, LongDouble) { std::numeric_limits<long double>::infinity(), -std::numeric_limits<long double>::infinity()}; + for (long double base : {1.L, 12.L, 123.L, 1234.L, 12345.L, 123456.L, + 1234567.L, 12345678.L, 123456789.L, 1234567890.L, + 12345678901.L, 123456789012.L, 1234567890123.L, + // This value is not representable in double, but it + // is in long double that uses the extended format. + // This is to verify that we are not truncating the + // value mistakenly through a double. + 10000000000000000.25L}) { + for (int exp : {-1000, -500, 0, 500, 1000}) { + for (int sign : {1, -1}) { + doubles.push_back(sign * std::ldexp(base, exp)); + doubles.push_back(sign / std::ldexp(base, exp)); + } + } + } + + // Regression tests + // + // Using a string literal because not all platforms support hex literals or it + // might be out of range. + doubles.push_back(std::strtold("-0xf.ffffffb5feafffbp-16324L", nullptr)); + for (const char *fmt : kFormats) { for (char f : {'f', 'F', // 'g', 'G', // 'a', 'A', // 'e', 'E'}) { std::string fmt_str = std::string(fmt) + 'L' + f; + + if (fmt == absl::string_view("%.5000") && f != 'f' && f != 'F' && + f != 'a' && f != 'A') { + // This particular test takes way too long with snprintf. + // Disable for the case we are not implementing natively. + continue; + } + + if (f == 'a' || f == 'A') { + if (!native_traits.hex_float_has_glibc_rounding || + !native_traits.hex_float_optimizes_leading_digit_bit_count) { + continue; + } + } + for (auto d : doubles) { FormatArgImpl arg(d); UntypedFormatSpecImpl format(fmt_str); // We use ASSERT_EQ here because failures are usually correlated and a // bug would print way too many failed expectations causing the test to // time out. - ASSERT_EQ(StrPrint(fmt_str.c_str(), d), - FormatPack(format, {&arg, 1})) + ASSERT_EQ(StrPrint(fmt_str.c_str(), d), FormatPack(format, {&arg, 1})) << fmt_str << " " << StrPrint("%.18Lg", d) << " " - << StrPrint("%.999Lf", d); + << StrPrint("%La", d) << " " << StrPrint("%.1080Lf", d); } } } } -TEST_F(FormatConvertTest, IntAsFloat) { +TEST_F(FormatConvertTest, IntAsDouble) { + const NativePrintfTraits &native_traits = VerifyNativeImplementation(); const int kMin = std::numeric_limits<int>::min(); const int kMax = std::numeric_limits<int>::max(); const int ia[] = { @@ -593,14 +1148,17 @@ TEST_F(FormatConvertTest, IntAsFloat) { const char *fmt; }; const double dx = static_cast<double>(fx); - const Expectation kExpect[] = { - { __LINE__, StrPrint("%f", dx), "%f" }, - { __LINE__, StrPrint("%12f", dx), "%12f" }, - { __LINE__, StrPrint("%.12f", dx), "%.12f" }, - { __LINE__, StrPrint("%12a", dx), "%12a" }, - { __LINE__, StrPrint("%.12a", dx), "%.12a" }, + std::vector<Expectation> expect = { + {__LINE__, StrPrint("%f", dx), "%f"}, + {__LINE__, StrPrint("%12f", dx), "%12f"}, + {__LINE__, StrPrint("%.12f", dx), "%.12f"}, + {__LINE__, StrPrint("%.12a", dx), "%.12a"}, }; - for (const Expectation &e : kExpect) { + if (native_traits.hex_float_uses_minimal_precision_when_not_specified) { + Expectation ex = {__LINE__, StrPrint("%12a", dx), "%12a"}; + expect.push_back(ex); + } + for (const Expectation &e : expect) { SCOPED_TRACE(e.line); SCOPED_TRACE(e.fmt); UntypedFormatSpecImpl format(e.fmt); @@ -645,6 +1203,25 @@ TEST_F(FormatConvertTest, ExpectedFailures) { EXPECT_TRUE(FormatFails("%*d", "")); } +// Sanity check to make sure that we are testing what we think we're testing on +// e.g. the x86_64+glibc platform. +TEST_F(FormatConvertTest, GlibcHasCorrectTraits) { +#if !defined(__GLIBC__) || !defined(__x86_64__) + return; +#endif + const NativePrintfTraits &native_traits = VerifyNativeImplementation(); + // If one of the following tests break then it is either because the above PP + // macro guards failed to exclude a new platform (likely) or because something + // has changed in the implemention of glibc sprintf float formatting behavior. + // If the latter, then the code that computes these flags needs to be + // revisited and/or possibly the StrFormat implementation. + EXPECT_TRUE(native_traits.hex_float_has_glibc_rounding); + EXPECT_TRUE(native_traits.hex_float_prefers_denormal_repr); + EXPECT_TRUE( + native_traits.hex_float_uses_minimal_precision_when_not_specified); + EXPECT_TRUE(native_traits.hex_float_optimizes_leading_digit_bit_count); +} + } // namespace } // namespace str_format_internal ABSL_NAMESPACE_END |