Export of internal Abseil changes

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ed829ac612f090375427c3488827c6e74deb2e3f by Derek Mauro <dmauro@google.com>:

Update latest GCC/Clang Linux tests to Bazel 5.0.0 and CMake 3.22.2

PiperOrigin-RevId: 429369775

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76952303c4d942288c4e7657ffb5893cec54a132 by Martijn Vels <mvels@google.com>:

Optimize Cord::ChunkIterator now that CordRepConcat is removed

PiperOrigin-RevId: 429321455

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dcd0d287793649aba9b98268c5783e449a34749f by Martijn Vels <mvels@google.com>:

Add IsDataEdge() and DataEdgeValue() helper functions.

This moves repetitive logic accessing data edges into its own header, and more strongly defines the notion of what a data edge is, enforcing the internal invariants. This will also be incorporated in optimized Cord iteration logic once CordRepConcat is totally removed from the Cord code.

PiperOrigin-RevId: 429307248

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6a0903962155988085bf8656743fda9c4cdcba6c by Abseil Team <absl-team@google.com>:

Make it clear that the probability function given for the zipf distribution is unnormalized, i.e., sum(p(x) for x = 0..k) != 100%.

Quoting Section 7 of the paper cited in the comments, where this formula comes from (emphasis mine): "We will consider the two parameter generalization as defined in Dagpunar [1988] with the *unnormalized* probability function ..."

PiperOrigin-RevId: 429068258

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3899ff6d444ba755148bc521a6ee031d9e9d4485 by Abseil Team <absl-team@google.com>:

Internal Changes

PiperOrigin-RevId: 428644856

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319de702d2b537cbb76c4c71277ae89b349b162e by Benjamin Barenblat <bbaren@google.com>:

Support symbolization on PA-RISC

Null out supervisor bits in PA-RISC addresses before symbolizing, and
handle function descriptor tables correctly.

Change symbolize_test.cc to use 32-bit aligned addresses, allowing that
test to pass on PA-RISC.

PiperOrigin-RevId: 428590564
GitOrigin-RevId: ed829ac612f090375427c3488827c6e74deb2e3f
Change-Id: Ie01ff3b9365fd45e5a55f858038552679f3180d3

1 files changed, 72 insertions, 0 deletions

diff --git a/absl/strings/cord_test.cc b/absl/strings/cord_test.cc
index c26e506d..9dcc4ce5 100644
--- a/absl/strings/cord_test.cc
+++ b/absl/strings/cord_test.cc
@@ -1866,6 +1866,78 @@ TEST_P(CordTest, CordChunkIteratorOperations) {
   VerifyChunkIterator(subcords, 128);
 }
 
+
+TEST_P(CordTest, AdvanceAndReadOnDataEdge) {
+  RandomEngine rng(GTEST_FLAG_GET(random_seed));
+  const std::string data = RandomLowercaseString(&rng, 2000);
+  for (bool as_flat : {true, false}) {
+    SCOPED_TRACE(as_flat ? "Flat" : "External");
+
+    absl::Cord cord =
+        as_flat ? absl::Cord(data)
+                : absl::MakeCordFromExternal(data, [](absl::string_view) {});
+    auto it = cord.Chars().begin();
+#if !defined(NDEBUG) || ABSL_OPTION_HARDENED
+    EXPECT_DEATH_IF_SUPPORTED(cord.AdvanceAndRead(&it, 2001), ".*");
+#endif
+
+    it = cord.Chars().begin();
+    absl::Cord frag = cord.AdvanceAndRead(&it, 2000);
+    EXPECT_EQ(frag, data);
+    EXPECT_TRUE(it == cord.Chars().end());
+
+    it = cord.Chars().begin();
+    frag = cord.AdvanceAndRead(&it, 200);
+    EXPECT_EQ(frag, data.substr(0, 200));
+    EXPECT_FALSE(it == cord.Chars().end());
+
+    frag = cord.AdvanceAndRead(&it, 1500);
+    EXPECT_EQ(frag, data.substr(200, 1500));
+    EXPECT_FALSE(it == cord.Chars().end());
+
+    frag = cord.AdvanceAndRead(&it, 300);
+    EXPECT_EQ(frag, data.substr(1700, 300));
+    EXPECT_TRUE(it == cord.Chars().end());
+  }
+}
+
+TEST_P(CordTest, AdvanceAndReadOnSubstringDataEdge) {
+  RandomEngine rng(GTEST_FLAG_GET(random_seed));
+  const std::string data = RandomLowercaseString(&rng, 2500);
+  for (bool as_flat : {true, false}) {
+    SCOPED_TRACE(as_flat ? "Flat" : "External");
+
+    absl::Cord cord =
+        as_flat ? absl::Cord(data)
+                : absl::MakeCordFromExternal(data, [](absl::string_view) {});
+    cord = cord.Subcord(200, 2000);
+    const std::string substr = data.substr(200, 2000);
+
+    auto it = cord.Chars().begin();
+#if !defined(NDEBUG) || ABSL_OPTION_HARDENED
+    EXPECT_DEATH_IF_SUPPORTED(cord.AdvanceAndRead(&it, 2001), ".*");
+#endif
+
+    it = cord.Chars().begin();
+    absl::Cord frag = cord.AdvanceAndRead(&it, 2000);
+    EXPECT_EQ(frag, substr);
+    EXPECT_TRUE(it == cord.Chars().end());
+
+    it = cord.Chars().begin();
+    frag = cord.AdvanceAndRead(&it, 200);
+    EXPECT_EQ(frag, substr.substr(0, 200));
+    EXPECT_FALSE(it == cord.Chars().end());
+
+    frag = cord.AdvanceAndRead(&it, 1500);
+    EXPECT_EQ(frag, substr.substr(200, 1500));
+    EXPECT_FALSE(it == cord.Chars().end());
+
+    frag = cord.AdvanceAndRead(&it, 300);
+    EXPECT_EQ(frag, substr.substr(1700, 300));
+    EXPECT_TRUE(it == cord.Chars().end());
+  }
+}
+
 TEST_P(CordTest, CharIteratorTraits) {
   static_assert(std::is_copy_constructible<absl::Cord::CharIterator>::value,
                 "");