Export of internal Abseil changes

--
f34cd235a12ad0ee1fea3a1ee5a427272dc2b285 by Abseil Team <absl-team@google.com>:

Migrates uses of deprecated map types to recommended types.

PiperOrigin-RevId: 309945156

--
e3410a47ad32c0775b6911610bc47b22938decad by Matthew Brown <matthewbr@google.com>:

Internal Change

PiperOrigin-RevId: 309856021

--
a58cfa25e0bb59e7fa9647ac1aae65eaccff0086 by Greg Falcon <gfalcon@google.com>:

Internal change.

PiperOrigin-RevId: 309804612

--
cdc5ec310035fbe25f496bda283fe655d94d7769 by Mark Barolak <mbar@google.com>:

Standardize the header comments for friend functions in cord.h

PiperOrigin-RevId: 309779073

--
fe61602701be795e54477b0fdbf5ffc1df12a6b7 by Samuel Benzaquen <sbenza@google.com>:

Implement %f natively for any input.
It evaluates the input at runtime and allocates stack space accordingly.

This removes a potential fallback into snprintf, improves performance, and removes all memory allocations in this formatting path.

PiperOrigin-RevId: 309752501

--
79e2a24f3f959e8b06ddf1d440bbabbd5f89b5b7 by Greg Falcon <gfalcon@google.com>:

Add a Cord::swap() method.  Many other Abseil types already provide this, but it was missing here.

We already provided a two-argument free function form of `swap()`, but that API is better suited for generic code.  The swap member function is a better API when the types are known.

PiperOrigin-RevId: 309751740

--
85cdf60024f153fb4fcb7fe68ed2b14b9faf119d by Derek Mauro <dmauro@google.com>:

Cleanup uses of "linker initialized" SpinLocks

PiperOrigin-RevId: 309581867

--
9e5443bfcec4b94056b13c75326576e987ab88fb by Matt Kulukundis <kfm@google.com>:

Clarify intended mixing properties of `absl::Hash`

PiperOrigin-RevId: 309520174

--
a0630f0827b67f217aaeae68a448fe4c1101e17d by Greg Falcon <gfalcon@google.com>:

Comment out a test in Emscripten to sidestep `long double` issues.

PiperOrigin-RevId: 309482953
GitOrigin-RevId: f34cd235a12ad0ee1fea3a1ee5a427272dc2b285
Change-Id: Icce0c9d547117374d596b9d684e4054ddd118669

1 files changed, 217 insertions, 28 deletions

diff --git a/absl/strings/internal/str_format/convert_test.cc b/absl/strings/internal/str_format/convert_test.cc
index cbcd7caf4665..dd167f76e68f 100644
--- a/absl/strings/internal/str_format/convert_test.cc
+++ b/absl/strings/internal/str_format/convert_test.cc
@@ -1,14 +1,18 @@
 #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/types/optional.h"
 
 namespace absl {
 ABSL_NAMESPACE_BEGIN
@@ -57,7 +61,7 @@ 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];
@@ -98,11 +102,18 @@ 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;
 }
@@ -471,8 +482,8 @@ TEST_F(FormatConvertTest, Float) {
 #endif  // _MSC_VER
 
   const char *const kFormats[] = {
-      "%",  "%.3",  "%8.5",   "%9",   "%.60", "%.30",   "%03",    "%+",
-      "% ", "%-10", "%#15.3", "%#.0", "%.0",  "%1$*2$", "%1$.*2$"};
+      "%",  "%.3", "%8.5", "%500",   "%.5000", "%.60", "%.30",   "%03",
+      "%+", "% ",  "%-10", "%#15.3", "%#.0",   "%.0",  "%1$*2$", "%1$.*2$"};
 
   std::vector<double> doubles = {0.0,
                                  -0.0,
@@ -489,11 +500,6 @@ 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 +518,204 @@ TEST_F(FormatConvertTest, Float) {
     }
   }
 
+  // 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
+
+  // 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);
+
   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') {
+        // This particular test takes way too long with snprintf.
+        // Disable for the case we are not implementing natively.
+        continue;
+      }
+
       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);
+
+        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("%.1080f", d);
+        }
       }
     }
   }
 }
 
+TEST_F(FormatConvertTest, FloatRound) {
+  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, 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 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(),
@@ -556,22 +723,44 @@ 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));
+      }
+    }
+  }
+
   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') {
+        // This particular test takes way too long with snprintf.
+        // Disable for the case we are not implementing natively.
+        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);
       }
     }
   }