1 files changed, 173 insertions, 0 deletions
diff --git a/absl/strings/cord_ring_reader_test.cc b/absl/strings/cord_ring_reader_test.cc
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+++ b/absl/strings/cord_ring_reader_test.cc
@@ -0,0 +1,173 @@
+// Copyright 2020 The Abseil Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <cstdlib>
+#include <ctime>
+#include <memory>
+#include <random>
+#include <sstream>
+
+#include "gmock/gmock.h"
+#include "gtest/gtest.h"
+#include "absl/debugging/leak_check.h"
+#include "absl/strings/internal/cord_internal.h"
+#include "absl/strings/internal/cord_rep_ring.h"
+#include "absl/strings/internal/cord_rep_ring_reader.h"
+#include "absl/strings/string_view.h"
+
+namespace absl {
+ABSL_NAMESPACE_BEGIN
+namespace cord_internal {
+namespace {
+
+using testing::Eq;
+
+// Creates a flat for testing
+CordRep* MakeFlat(absl::string_view s) {
+  CordRepFlat* flat = CordRepFlat::New(s.length());
+  memcpy(flat->Data(), s.data(), s.length());
+  flat->length = s.length();
+  return flat;
+}
+
+CordRepRing* FromFlats(Span<absl::string_view const> flats) {
+  CordRepRing* ring = CordRepRing::Create(MakeFlat(flats[0]), flats.size() - 1);
+  for (int i = 1; i < flats.size(); ++i) {
+    ring = CordRepRing::Append(ring, MakeFlat(flats[i]));
+  }
+  return ring;
+}
+
+std::array<absl::string_view, 12> TestFlats() {
+  return {"abcdefghij", "klmnopqrst", "uvwxyz",     "ABCDEFGHIJ",
+          "KLMNOPQRST", "UVWXYZ",     "1234567890", "~!@#$%^&*()_",
+          "+-=",        "[]\\{}|;':", ",/<>?",      "."};
+}
+
+TEST(CordRingReaderTest, DefaultInstance) {
+  CordRepRingReader reader;
+  EXPECT_FALSE(static_cast<bool>(reader));
+  EXPECT_THAT(reader.ring(), Eq(nullptr));
+#ifndef NDEBUG
+  EXPECT_DEATH_IF_SUPPORTED(reader.length(), ".*");
+  EXPECT_DEATH_IF_SUPPORTED(reader.consumed(), ".*");
+  EXPECT_DEATH_IF_SUPPORTED(reader.remaining(), ".*");
+  EXPECT_DEATH_IF_SUPPORTED(reader.Next(), ".*");
+  EXPECT_DEATH_IF_SUPPORTED(reader.Seek(0), ".*");
+#endif
+}
+
+TEST(CordRingReaderTest, Reset) {
+  CordRepRingReader reader;
+  auto flats = TestFlats();
+  CordRepRing* ring = FromFlats(flats);
+
+  absl::string_view first = reader.Reset(ring);
+  EXPECT_THAT(first, Eq(flats[0]));
+  EXPECT_TRUE(static_cast<bool>(reader));
+  EXPECT_THAT(reader.ring(), Eq(ring));
+  EXPECT_THAT(reader.index(), Eq(ring->head()));
+  EXPECT_THAT(reader.length(), Eq(ring->length));
+  EXPECT_THAT(reader.consumed(), Eq(flats[0].length()));
+  EXPECT_THAT(reader.remaining(), Eq(ring->length - reader.consumed()));
+
+  reader.Reset();
+  EXPECT_FALSE(static_cast<bool>(reader));
+  EXPECT_THAT(reader.ring(), Eq(nullptr));
+
+  CordRep::Unref(ring);
+}
+
+TEST(CordRingReaderTest, Next) {
+  CordRepRingReader reader;
+  auto flats = TestFlats();
+  CordRepRing* ring = FromFlats(flats);
+  CordRepRing::index_type head = ring->head();
+
+  reader.Reset(ring);
+  size_t consumed = reader.consumed();
+  size_t remaining = reader.remaining();
+  for (int i = 1; i < flats.size(); ++i) {
+    consumed += flats[i].length();
+    remaining -= flats[i].length();
+    absl::string_view next = reader.Next();
+    ASSERT_THAT(next, Eq(flats[i]));
+    ASSERT_THAT(reader.index(), Eq(ring->advance(head, i)));
+    ASSERT_THAT(reader.consumed(), Eq(consumed));
+    ASSERT_THAT(reader.remaining(), Eq(remaining));
+  }
+
+#ifndef NDEBUG
+  EXPECT_DEATH_IF_SUPPORTED(reader.Next(), ".*");
+#endif
+
+  CordRep::Unref(ring);
+}
+
+TEST(CordRingReaderTest, SeekForward) {
+  CordRepRingReader reader;
+  auto flats = TestFlats();
+  CordRepRing* ring = FromFlats(flats);
+  CordRepRing::index_type head = ring->head();
+
+  reader.Reset(ring);
+  size_t consumed = 0;
+  size_t remaining = ring->length;;
+  for (int i = 0; i < flats.size(); ++i) {
+    size_t offset = consumed;
+    consumed += flats[i].length();
+    remaining -= flats[i].length();
+    for (int off = 0; off < flats[i].length(); ++off) {
+      absl::string_view chunk = reader.Seek(offset + off);
+      ASSERT_THAT(chunk, Eq(flats[i].substr(off)));
+      ASSERT_THAT(reader.index(), Eq(ring->advance(head, i)));
+      ASSERT_THAT(reader.consumed(), Eq(consumed));
+      ASSERT_THAT(reader.remaining(), Eq(remaining));
+    }
+  }
+
+  CordRep::Unref(ring);
+}
+
+TEST(CordRingReaderTest, SeekBackward) {
+  CordRepRingReader reader;
+  auto flats = TestFlats();
+  CordRepRing* ring = FromFlats(flats);
+  CordRepRing::index_type head = ring->head();
+
+  reader.Reset(ring);
+  size_t consumed = ring->length;
+  size_t remaining = 0;
+  for (int i = flats.size() - 1; i >= 0; --i) {
+    size_t offset = consumed - flats[i].length();
+    for (int off = 0; off < flats[i].length(); ++off) {
+      absl::string_view chunk = reader.Seek(offset + off);
+      ASSERT_THAT(chunk, Eq(flats[i].substr(off)));
+      ASSERT_THAT(reader.index(), Eq(ring->advance(head, i)));
+      ASSERT_THAT(reader.consumed(), Eq(consumed));
+      ASSERT_THAT(reader.remaining(), Eq(remaining));
+    }
+    consumed -= flats[i].length();
+    remaining += flats[i].length();
+  }
+#ifndef NDEBUG
+  EXPECT_DEATH_IF_SUPPORTED(reader.Seek(ring->length), ".*");
+#endif
+  CordRep::Unref(ring);
+}
+
+}  // namespace
+}  // namespace cord_internal
+ABSL_NAMESPACE_END
+}  // namespace absl