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cord_test.cc
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// 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 "absl/strings/cord.h"
#include <algorithm>
#include <climits>
#include <cstdio>
#include <iterator>
#include <map>
#include <numeric>
#include <random>
#include <sstream>
#include <type_traits>
#include <utility>
#include <vector>
#include "gmock/gmock.h"
#include "gtest/gtest.h"
#include "absl/base/casts.h"
#include "absl/base/config.h"
#include "absl/base/internal/endian.h"
#include "absl/base/internal/raw_logging.h"
#include "absl/base/macros.h"
#include "absl/container/fixed_array.h"
#include "absl/strings/cord_test_helpers.h"
#include "absl/strings/cordz_test_helpers.h"
#include "absl/strings/str_cat.h"
#include "absl/strings/str_format.h"
#include "absl/strings/string_view.h"
typedef std::mt19937_64 RandomEngine;
static std::string RandomLowercaseString(RandomEngine* rng);
static std::string RandomLowercaseString(RandomEngine* rng, size_t length);
static int GetUniformRandomUpTo(RandomEngine* rng, int upper_bound) {
if (upper_bound > 0) {
std::uniform_int_distribution<int> uniform(0, upper_bound - 1);
return uniform(*rng);
} else {
return 0;
}
}
static size_t GetUniformRandomUpTo(RandomEngine* rng, size_t upper_bound) {
if (upper_bound > 0) {
std::uniform_int_distribution<size_t> uniform(0, upper_bound - 1);
return uniform(*rng);
} else {
return 0;
}
}
static int32_t GenerateSkewedRandom(RandomEngine* rng, int max_log) {
const uint32_t base = (*rng)() % (max_log + 1);
const uint32_t mask = ((base < 32) ? (1u << base) : 0u) - 1u;
return (*rng)() & mask;
}
static std::string RandomLowercaseString(RandomEngine* rng) {
int length;
std::bernoulli_distribution one_in_1k(0.001);
std::bernoulli_distribution one_in_10k(0.0001);
// With low probability, make a large fragment
if (one_in_10k(*rng)) {
length = GetUniformRandomUpTo(rng, 1048576);
} else if (one_in_1k(*rng)) {
length = GetUniformRandomUpTo(rng, 10000);
} else {
length = GenerateSkewedRandom(rng, 10);
}
return RandomLowercaseString(rng, length);
}
static std::string RandomLowercaseString(RandomEngine* rng, size_t length) {
std::string result(length, '\0');
std::uniform_int_distribution<int> chars('a', 'z');
std::generate(result.begin(), result.end(),
[&]() { return static_cast<char>(chars(*rng)); });
return result;
}
static void DoNothing(absl::string_view /* data */, void* /* arg */) {}
static void DeleteExternalString(absl::string_view data, void* arg) {
std::string* s = reinterpret_cast<std::string*>(arg);
EXPECT_EQ(data, *s);
delete s;
}
// Add "s" to *dst via `MakeCordFromExternal`
static void AddExternalMemory(absl::string_view s, absl::Cord* dst) {
std::string* str = new std::string(s.data(), s.size());
dst->Append(absl::MakeCordFromExternal(*str, [str](absl::string_view data) {
DeleteExternalString(data, str);
}));
}
static void DumpGrowth() {
absl::Cord str;
for (int i = 0; i < 1000; i++) {
char c = 'a' + i % 26;
str.Append(absl::string_view(&c, 1));
}
}
// Make a Cord with some number of fragments. Return the size (in bytes)
// of the smallest fragment.
static size_t AppendWithFragments(const std::string& s, RandomEngine* rng,
absl::Cord* cord) {
size_t j = 0;
const size_t max_size = s.size() / 5; // Make approx. 10 fragments
size_t min_size = max_size; // size of smallest fragment
while (j < s.size()) {
size_t N = 1 + GetUniformRandomUpTo(rng, max_size);
if (N > (s.size() - j)) {
N = s.size() - j;
}
if (N < min_size) {
min_size = N;
}
std::bernoulli_distribution coin_flip(0.5);
if (coin_flip(*rng)) {
// Grow by adding an external-memory.
AddExternalMemory(absl::string_view(s.data() + j, N), cord);
} else {
cord->Append(absl::string_view(s.data() + j, N));
}
j += N;
}
return min_size;
}
// Add an external memory that contains the specified std::string to cord
static void AddNewStringBlock(const std::string& str, absl::Cord* dst) {
char* data = new char[str.size()];
memcpy(data, str.data(), str.size());
dst->Append(absl::MakeCordFromExternal(
absl::string_view(data, str.size()),
[](absl::string_view s) { delete[] s.data(); }));
}
// Make a Cord out of many different types of nodes.
static absl::Cord MakeComposite() {
absl::Cord cord;
cord.Append("the");
AddExternalMemory(" quick brown", &cord);
AddExternalMemory(" fox jumped", &cord);
absl::Cord full(" over");
AddExternalMemory(" the lazy", &full);
AddNewStringBlock(" dog slept the whole day away", &full);
absl::Cord substring = full.Subcord(0, 18);
// Make substring long enough to defeat the copying fast path in Append.
substring.Append(std::string(1000, '.'));
cord.Append(substring);
cord = cord.Subcord(0, cord.size() - 998); // Remove most of extra junk
return cord;
}
namespace absl {
ABSL_NAMESPACE_BEGIN
class CordTestPeer {
public:
static void ForEachChunk(
const Cord& c, absl::FunctionRef<void(absl::string_view)> callback) {
c.ForEachChunk(callback);
}
static bool IsTree(const Cord& c) { return c.contents_.is_tree(); }
static cord_internal::CordzInfo* GetCordzInfo(const Cord& c) {
return c.contents_.cordz_info();
}
static Cord MakeSubstring(Cord src, size_t offset, size_t length) {
ABSL_RAW_CHECK(src.contents_.is_tree(), "Can not be inlined");
Cord cord;
auto* rep = new cord_internal::CordRepSubstring;
rep->tag = cord_internal::SUBSTRING;
rep->child = cord_internal::CordRep::Ref(src.contents_.tree());
rep->start = offset;
rep->length = length;
cord.contents_.EmplaceTree(rep,
cord_internal::CordzUpdateTracker::kSubCord);
return cord;
}
};
ABSL_NAMESPACE_END
} // namespace absl
TEST(Cord, AllFlatSizes) {
using absl::strings_internal::CordTestAccess;
for (size_t s = 0; s < CordTestAccess::MaxFlatLength(); s++) {
// Make a string of length s.
std::string src;
while (src.size() < s) {
src.push_back('a' + (src.size() % 26));
}
absl::Cord dst(src);
EXPECT_EQ(std::string(dst), src) << s;
}
}
// We create a Cord at least 128GB in size using the fact that Cords can
// internally reference-count; thus the Cord is enormous without actually
// consuming very much memory.
TEST(GigabyteCord, FromExternal) {
const size_t one_gig = 1024U * 1024U * 1024U;
size_t max_size = 2 * one_gig;
if (sizeof(max_size) > 4) max_size = 128 * one_gig;
size_t length = 128 * 1024;
char* data = new char[length];
absl::Cord from = absl::MakeCordFromExternal(
absl::string_view(data, length),
[](absl::string_view sv) { delete[] sv.data(); });
// This loop may seem odd due to its combination of exponential doubling of
// size and incremental size increases. We do it incrementally to be sure the
// Cord will need rebalancing and will exercise code that, in the past, has
// caused crashes in production. We grow exponentially so that the code will
// execute in a reasonable amount of time.
absl::Cord c;
c.Append(from);
while (c.size() < max_size) {
c.Append(c);
c.Append(from);
c.Append(from);
c.Append(from);
c.Append(from);
}
for (int i = 0; i < 1024; ++i) {
c.Append(from);
}
ABSL_RAW_LOG(INFO, "Made a Cord with %zu bytes!", c.size());
// Note: on a 32-bit build, this comes out to 2,818,048,000 bytes.
// Note: on a 64-bit build, this comes out to 171,932,385,280 bytes.
}
static absl::Cord MakeExternalCord(int size) {
char* buffer = new char[size];
memset(buffer, 'x', size);
absl::Cord cord;
cord.Append(absl::MakeCordFromExternal(
absl::string_view(buffer, size),
[](absl::string_view s) { delete[] s.data(); }));
return cord;
}
// Extern to fool clang that this is not constant. Needed to suppress
// a warning of unsafe code we want to test.
extern bool my_unique_true_boolean;
bool my_unique_true_boolean = true;
TEST(Cord, Assignment) {
absl::Cord x(absl::string_view("hi there"));
absl::Cord y(x);
ASSERT_EQ(std::string(x), "hi there");
ASSERT_EQ(std::string(y), "hi there");
ASSERT_TRUE(x == y);
ASSERT_TRUE(x <= y);
ASSERT_TRUE(y <= x);
x = absl::string_view("foo");
ASSERT_EQ(std::string(x), "foo");
ASSERT_EQ(std::string(y), "hi there");
ASSERT_TRUE(x < y);
ASSERT_TRUE(y > x);
ASSERT_TRUE(x != y);
ASSERT_TRUE(x <= y);
ASSERT_TRUE(y >= x);
x = "foo";
ASSERT_EQ(x, "foo");
// Test that going from inline rep to tree we don't leak memory.
std::vector<std::pair<absl::string_view, absl::string_view>>
test_string_pairs = {{"hi there", "foo"},
{"loooooong coooooord", "short cord"},
{"short cord", "loooooong coooooord"},
{"loooooong coooooord1", "loooooong coooooord2"}};
for (std::pair<absl::string_view, absl::string_view> test_strings :
test_string_pairs) {
absl::Cord tmp(test_strings.first);
absl::Cord z(std::move(tmp));
ASSERT_EQ(std::string(z), test_strings.first);
tmp = test_strings.second;
z = std::move(tmp);
ASSERT_EQ(std::string(z), test_strings.second);
}
{
// Test that self-move assignment doesn't crash/leak.
// Do not write such code!
absl::Cord my_small_cord("foo");
absl::Cord my_big_cord("loooooong coooooord");
// Bypass clang's warning on self move-assignment.
absl::Cord* my_small_alias =
my_unique_true_boolean ? &my_small_cord : &my_big_cord;
absl::Cord* my_big_alias =
!my_unique_true_boolean ? &my_small_cord : &my_big_cord;
*my_small_alias = std::move(my_small_cord);
*my_big_alias = std::move(my_big_cord);
// my_small_cord and my_big_cord are in an unspecified but valid
// state, and will be correctly destroyed here.
}
}
TEST(Cord, StartsEndsWith) {
absl::Cord x(absl::string_view("abcde"));
absl::Cord empty("");
ASSERT_TRUE(x.StartsWith(absl::Cord("abcde")));
ASSERT_TRUE(x.StartsWith(absl::Cord("abc")));
ASSERT_TRUE(x.StartsWith(absl::Cord("")));
ASSERT_TRUE(empty.StartsWith(absl::Cord("")));
ASSERT_TRUE(x.EndsWith(absl::Cord("abcde")));
ASSERT_TRUE(x.EndsWith(absl::Cord("cde")));
ASSERT_TRUE(x.EndsWith(absl::Cord("")));
ASSERT_TRUE(empty.EndsWith(absl::Cord("")));
ASSERT_TRUE(!x.StartsWith(absl::Cord("xyz")));
ASSERT_TRUE(!empty.StartsWith(absl::Cord("xyz")));
ASSERT_TRUE(!x.EndsWith(absl::Cord("xyz")));
ASSERT_TRUE(!empty.EndsWith(absl::Cord("xyz")));
ASSERT_TRUE(x.StartsWith("abcde"));
ASSERT_TRUE(x.StartsWith("abc"));
ASSERT_TRUE(x.StartsWith(""));
ASSERT_TRUE(empty.StartsWith(""));
ASSERT_TRUE(x.EndsWith("abcde"));
ASSERT_TRUE(x.EndsWith("cde"));
ASSERT_TRUE(x.EndsWith(""));
ASSERT_TRUE(empty.EndsWith(""));
ASSERT_TRUE(!x.StartsWith("xyz"));
ASSERT_TRUE(!empty.StartsWith("xyz"));
ASSERT_TRUE(!x.EndsWith("xyz"));
ASSERT_TRUE(!empty.EndsWith("xyz"));
}
TEST(Cord, Subcord) {
RandomEngine rng(testing::GTEST_FLAG(random_seed));
const std::string s = RandomLowercaseString(&rng, 1024);
absl::Cord a;
AppendWithFragments(s, &rng, &a);
ASSERT_EQ(s.size(), a.size());
// Check subcords of a, from a variety of interesting points.
std::set<size_t> positions;
for (int i = 0; i <= 32; ++i) {
positions.insert(i);
positions.insert(i * 32 - 1);
positions.insert(i * 32);
positions.insert(i * 32 + 1);
positions.insert(a.size() - i);
}
positions.insert(237);
positions.insert(732);
for (size_t pos : positions) {
if (pos > a.size()) continue;
for (size_t end_pos : positions) {
if (end_pos < pos || end_pos > a.size()) continue;
absl::Cord sa = a.Subcord(pos, end_pos - pos);
ASSERT_EQ(absl::string_view(s).substr(pos, end_pos - pos),
std::string(sa))
<< a;
}
}
// Do the same thing for an inline cord.
const std::string sh = "short";
absl::Cord c(sh);
for (size_t pos = 0; pos <= sh.size(); ++pos) {
for (size_t n = 0; n <= sh.size() - pos; ++n) {
absl::Cord sc = c.Subcord(pos, n);
ASSERT_EQ(sh.substr(pos, n), std::string(sc)) << c;
}
}
// Check subcords of subcords.
absl::Cord sa = a.Subcord(0, a.size());
std::string ss = s.substr(0, s.size());
while (sa.size() > 1) {
sa = sa.Subcord(1, sa.size() - 2);
ss = ss.substr(1, ss.size() - 2);
ASSERT_EQ(ss, std::string(sa)) << a;
if (HasFailure()) break; // halt cascade
}
// It is OK to ask for too much.
sa = a.Subcord(0, a.size() + 1);
EXPECT_EQ(s, std::string(sa));
// It is OK to ask for something beyond the end.
sa = a.Subcord(a.size() + 1, 0);
EXPECT_TRUE(sa.empty());
sa = a.Subcord(a.size() + 1, 1);
EXPECT_TRUE(sa.empty());
}
TEST(Cord, Swap) {
absl::string_view a("Dexter");
absl::string_view b("Mandark");
absl::Cord x(a);
absl::Cord y(b);
swap(x, y);
ASSERT_EQ(x, absl::Cord(b));
ASSERT_EQ(y, absl::Cord(a));
x.swap(y);
ASSERT_EQ(x, absl::Cord(a));
ASSERT_EQ(y, absl::Cord(b));
}
static void VerifyCopyToString(const absl::Cord& cord) {
std::string initially_empty;
absl::CopyCordToString(cord, &initially_empty);
EXPECT_EQ(initially_empty, cord);
constexpr size_t kInitialLength = 1024;
std::string has_initial_contents(kInitialLength, 'x');
const char* address_before_copy = has_initial_contents.data();
absl::CopyCordToString(cord, &has_initial_contents);
EXPECT_EQ(has_initial_contents, cord);
if (cord.size() <= kInitialLength) {
EXPECT_EQ(has_initial_contents.data(), address_before_copy)
<< "CopyCordToString allocated new string storage; "
"has_initial_contents = \""
<< has_initial_contents << "\"";
}
}
TEST(Cord, CopyToString) {
VerifyCopyToString(absl::Cord());
VerifyCopyToString(absl::Cord("small cord"));
VerifyCopyToString(
absl::MakeFragmentedCord({"fragmented ", "cord ", "to ", "test ",
"copying ", "to ", "a ", "string."}));
}
TEST(TryFlat, Empty) {
absl::Cord c;
EXPECT_EQ(c.TryFlat(), "");
}
TEST(TryFlat, Flat) {
absl::Cord c("hello");
EXPECT_EQ(c.TryFlat(), "hello");
}
TEST(TryFlat, SubstrInlined) {
absl::Cord c("hello");
c.RemovePrefix(1);
EXPECT_EQ(c.TryFlat(), "ello");
}
TEST(TryFlat, SubstrFlat) {
absl::Cord c("longer than 15 bytes");
absl::Cord sub = absl::CordTestPeer::MakeSubstring(c, 1, c.size() - 1);
EXPECT_EQ(sub.TryFlat(), "onger than 15 bytes");
}
TEST(TryFlat, Concat) {
absl::Cord c = absl::MakeFragmentedCord({"hel", "lo"});
EXPECT_EQ(c.TryFlat(), absl::nullopt);
}
TEST(TryFlat, External) {
absl::Cord c = absl::MakeCordFromExternal("hell", [](absl::string_view) {});
EXPECT_EQ(c.TryFlat(), "hell");
}
TEST(TryFlat, SubstrExternal) {
absl::Cord c = absl::MakeCordFromExternal("hell", [](absl::string_view) {});
absl::Cord sub = absl::CordTestPeer::MakeSubstring(c, 1, c.size() - 1);
EXPECT_EQ(sub.TryFlat(), "ell");
}
TEST(TryFlat, SubstrConcat) {
absl::Cord c = absl::MakeFragmentedCord({"hello", " world"});
absl::Cord sub = absl::CordTestPeer::MakeSubstring(c, 1, c.size() - 1);
EXPECT_EQ(sub.TryFlat(), absl::nullopt);
c.RemovePrefix(1);
EXPECT_EQ(c.TryFlat(), absl::nullopt);
}
TEST(TryFlat, CommonlyAssumedInvariants) {
// The behavior tested below is not part of the API contract of Cord, but it's
// something we intend to be true in our current implementation. This test
// exists to detect and prevent accidental breakage of the implementation.
absl::string_view fragments[] = {"A fragmented test",
" cord",
" to test subcords",
" of ",
"a",
" cord for",
" each chunk "
"returned by the ",
"iterator"};
absl::Cord c = absl::MakeFragmentedCord(fragments);
int fragment = 0;
int offset = 0;
absl::Cord::CharIterator itc = c.char_begin();
for (absl::string_view sv : c.Chunks()) {
absl::string_view expected = fragments[fragment];
absl::Cord subcord1 = c.Subcord(offset, sv.length());
absl::Cord subcord2 = absl::Cord::AdvanceAndRead(&itc, sv.size());
EXPECT_EQ(subcord1.TryFlat(), expected);
EXPECT_EQ(subcord2.TryFlat(), expected);
++fragment;
offset += sv.length();
}
}
static bool IsFlat(const absl::Cord& c) {
return c.chunk_begin() == c.chunk_end() || ++c.chunk_begin() == c.chunk_end();
}
static void VerifyFlatten(absl::Cord c) {
std::string old_contents(c);
absl::string_view old_flat;
bool already_flat_and_non_empty = IsFlat(c) && !c.empty();
if (already_flat_and_non_empty) {
old_flat = *c.chunk_begin();
}
absl::string_view new_flat = c.Flatten();
// Verify that the contents of the flattened Cord are correct.
EXPECT_EQ(new_flat, old_contents);
EXPECT_EQ(std::string(c), old_contents);
// If the Cord contained data and was already flat, verify that the data
// wasn't copied.
if (already_flat_and_non_empty) {
EXPECT_EQ(old_flat.data(), new_flat.data())
<< "Allocated new memory even though the Cord was already flat.";
}
// Verify that the flattened Cord is in fact flat.
EXPECT_TRUE(IsFlat(c));
}
TEST(Cord, Flatten) {
VerifyFlatten(absl::Cord());
VerifyFlatten(absl::Cord("small cord"));
VerifyFlatten(absl::Cord("larger than small buffer optimization"));
VerifyFlatten(absl::MakeFragmentedCord({"small ", "fragmented ", "cord"}));
// Test with a cord that is longer than the largest flat buffer
RandomEngine rng(testing::GTEST_FLAG(random_seed));
VerifyFlatten(absl::Cord(RandomLowercaseString(&rng, 8192)));
}
// Test data
namespace {
class TestData {
private:
std::vector<std::string> data_;
// Return a std::string of the specified length.
static std::string MakeString(int length) {
std::string result;
char buf[30];
snprintf(buf, sizeof(buf), "(%d)", length);
while (result.size() < length) {
result += buf;
}
result.resize(length);
return result;
}
public:
TestData() {
// short strings increasing in length by one
for (int i = 0; i < 30; i++) {
data_.push_back(MakeString(i));
}
// strings around half kMaxFlatLength
static const int kMaxFlatLength = 4096 - 9;
static const int kHalf = kMaxFlatLength / 2;
for (int i = -10; i <= +10; i++) {
data_.push_back(MakeString(kHalf + i));
}
for (int i = -10; i <= +10; i++) {
data_.push_back(MakeString(kMaxFlatLength + i));
}
}
size_t size() const { return data_.size(); }
const std::string& data(size_t i) const { return data_[i]; }
};
} // namespace
TEST(Cord, MultipleLengths) {
TestData d;
for (size_t i = 0; i < d.size(); i++) {
std::string a = d.data(i);
{ // Construct from Cord
absl::Cord tmp(a);
absl::Cord x(tmp);
EXPECT_EQ(a, std::string(x)) << "'" << a << "'";
}
{ // Construct from absl::string_view
absl::Cord x(a);
EXPECT_EQ(a, std::string(x)) << "'" << a << "'";
}
{ // Append cord to self
absl::Cord self(a);
self.Append(self);
EXPECT_EQ(a + a, std::string(self)) << "'" << a << "' + '" << a << "'";
}
{ // Prepend cord to self
absl::Cord self(a);
self.Prepend(self);
EXPECT_EQ(a + a, std::string(self)) << "'" << a << "' + '" << a << "'";
}
// Try to append/prepend others
for (size_t j = 0; j < d.size(); j++) {
std::string b = d.data(j);
{ // CopyFrom Cord
absl::Cord x(a);
absl::Cord y(b);
x = y;
EXPECT_EQ(b, std::string(x)) << "'" << a << "' + '" << b << "'";
}
{ // CopyFrom absl::string_view
absl::Cord x(a);
x = b;
EXPECT_EQ(b, std::string(x)) << "'" << a << "' + '" << b << "'";
}
{ // Cord::Append(Cord)
absl::Cord x(a);
absl::Cord y(b);
x.Append(y);
EXPECT_EQ(a + b, std::string(x)) << "'" << a << "' + '" << b << "'";
}
{ // Cord::Append(absl::string_view)
absl::Cord x(a);
x.Append(b);
EXPECT_EQ(a + b, std::string(x)) << "'" << a << "' + '" << b << "'";
}
{ // Cord::Prepend(Cord)
absl::Cord x(a);
absl::Cord y(b);
x.Prepend(y);
EXPECT_EQ(b + a, std::string(x)) << "'" << b << "' + '" << a << "'";
}
{ // Cord::Prepend(absl::string_view)
absl::Cord x(a);
x.Prepend(b);
EXPECT_EQ(b + a, std::string(x)) << "'" << b << "' + '" << a << "'";
}
}
}
}
namespace {
TEST(Cord, RemoveSuffixWithExternalOrSubstring) {
absl::Cord cord = absl::MakeCordFromExternal(
"foo bar baz", [](absl::string_view s) { DoNothing(s, nullptr); });
EXPECT_EQ("foo bar baz", std::string(cord));
// This RemoveSuffix() will wrap the EXTERNAL node in a SUBSTRING node.
cord.RemoveSuffix(4);
EXPECT_EQ("foo bar", std::string(cord));
// This RemoveSuffix() will adjust the SUBSTRING node in-place.
cord.RemoveSuffix(4);
EXPECT_EQ("foo", std::string(cord));
}
TEST(Cord, RemoveSuffixMakesZeroLengthNode) {
absl::Cord c;
c.Append(absl::Cord(std::string(100, 'x')));
absl::Cord other_ref = c; // Prevent inplace appends
c.Append(absl::Cord(std::string(200, 'y')));
c.RemoveSuffix(200);
EXPECT_EQ(std::string(100, 'x'), std::string(c));
}
} // namespace
// CordSpliceTest contributed by hendrie.
namespace {
// Create a cord with an external memory block filled with 'z'
absl::Cord CordWithZedBlock(size_t size) {
char* data = new char[size];
if (size > 0) {
memset(data, 'z', size);
}
absl::Cord cord = absl::MakeCordFromExternal(
absl::string_view(data, size),
[](absl::string_view s) { delete[] s.data(); });
return cord;
}
// Establish that ZedBlock does what we think it does.
TEST(CordSpliceTest, ZedBlock) {
absl::Cord blob = CordWithZedBlock(10);
EXPECT_EQ(10, blob.size());
std::string s;
absl::CopyCordToString(blob, &s);
EXPECT_EQ("zzzzzzzzzz", s);
}
TEST(CordSpliceTest, ZedBlock0) {
absl::Cord blob = CordWithZedBlock(0);
EXPECT_EQ(0, blob.size());
std::string s;
absl::CopyCordToString(blob, &s);
EXPECT_EQ("", s);
}
TEST(CordSpliceTest, ZedBlockSuffix1) {
absl::Cord blob = CordWithZedBlock(10);
EXPECT_EQ(10, blob.size());
absl::Cord suffix(blob);
suffix.RemovePrefix(9);
EXPECT_EQ(1, suffix.size());
std::string s;
absl::CopyCordToString(suffix, &s);
EXPECT_EQ("z", s);
}
// Remove all of a prefix block
TEST(CordSpliceTest, ZedBlockSuffix0) {
absl::Cord blob = CordWithZedBlock(10);
EXPECT_EQ(10, blob.size());
absl::Cord suffix(blob);
suffix.RemovePrefix(10);
EXPECT_EQ(0, suffix.size());
std::string s;
absl::CopyCordToString(suffix, &s);
EXPECT_EQ("", s);
}
absl::Cord BigCord(size_t len, char v) {
std::string s(len, v);
return absl::Cord(s);
}
// Splice block into cord.
absl::Cord SpliceCord(const absl::Cord& blob, int64_t offset,
const absl::Cord& block) {
ABSL_RAW_CHECK(offset >= 0, "");
ABSL_RAW_CHECK(offset + block.size() <= blob.size(), "");
absl::Cord result(blob);
result.RemoveSuffix(blob.size() - offset);
result.Append(block);
absl::Cord suffix(blob);
suffix.RemovePrefix(offset + block.size());
result.Append(suffix);
ABSL_RAW_CHECK(blob.size() == result.size(), "");
return result;
}
// Taking an empty suffix of a block breaks appending.
TEST(CordSpliceTest, RemoveEntireBlock1) {
absl::Cord zero = CordWithZedBlock(10);
absl::Cord suffix(zero);
suffix.RemovePrefix(10);
absl::Cord result;
result.Append(suffix);
}
TEST(CordSpliceTest, RemoveEntireBlock2) {
absl::Cord zero = CordWithZedBlock(10);
absl::Cord prefix(zero);
prefix.RemoveSuffix(10);
absl::Cord suffix(zero);
suffix.RemovePrefix(10);
absl::Cord result(prefix);
result.Append(suffix);
}
TEST(CordSpliceTest, RemoveEntireBlock3) {
absl::Cord blob = CordWithZedBlock(10);
absl::Cord block = BigCord(10, 'b');
blob = SpliceCord(blob, 0, block);
}
struct CordCompareTestCase {
template <typename LHS, typename RHS>
CordCompareTestCase(const LHS& lhs, const RHS& rhs)
: lhs_cord(lhs), rhs_cord(rhs) {}
absl::Cord lhs_cord;
absl::Cord rhs_cord;
};
const auto sign = [](int x) { return x == 0 ? 0 : (x > 0 ? 1 : -1); };
void VerifyComparison(const CordCompareTestCase& test_case) {
std::string lhs_string(test_case.lhs_cord);
std::string rhs_string(test_case.rhs_cord);
int expected = sign(lhs_string.compare(rhs_string));
EXPECT_EQ(expected, test_case.lhs_cord.Compare(test_case.rhs_cord))
<< "LHS=" << lhs_string << "; RHS=" << rhs_string;
EXPECT_EQ(expected, test_case.lhs_cord.Compare(rhs_string))
<< "LHS=" << lhs_string << "; RHS=" << rhs_string;
EXPECT_EQ(-expected, test_case.rhs_cord.Compare(test_case.lhs_cord))
<< "LHS=" << rhs_string << "; RHS=" << lhs_string;
EXPECT_EQ(-expected, test_case.rhs_cord.Compare(lhs_string))
<< "LHS=" << rhs_string << "; RHS=" << lhs_string;
}
TEST(Cord, Compare) {
absl::Cord subcord("aaaaaBBBBBcccccDDDDD");
subcord = subcord.Subcord(3, 10);
absl::Cord tmp("aaaaaaaaaaaaaaaa");
tmp.Append("BBBBBBBBBBBBBBBB");
absl::Cord concat = absl::Cord("cccccccccccccccc");
concat.Append("DDDDDDDDDDDDDDDD");
concat.Prepend(tmp);
absl::Cord concat2("aaaaaaaaaaaaa");
concat2.Append("aaaBBBBBBBBBBBBBBBBccccc");
concat2.Append("cccccccccccDDDDDDDDDDDDDD");
concat2.Append("DD");
std::vector<CordCompareTestCase> test_cases = {{
// Inline cords
{"abcdef", "abcdef"},
{"abcdef", "abcdee"},
{"abcdef", "abcdeg"},
{"bbcdef", "abcdef"},
{"bbcdef", "abcdeg"},
{"abcdefa", "abcdef"},
{"abcdef", "abcdefa"},
// Small flat cords
{"aaaaaBBBBBcccccDDDDD", "aaaaaBBBBBcccccDDDDD"},
{"aaaaaBBBBBcccccDDDDD", "aaaaaBBBBBxccccDDDDD"},
{"aaaaaBBBBBcxcccDDDDD", "aaaaaBBBBBcccccDDDDD"},
{"aaaaaBBBBBxccccDDDDD", "aaaaaBBBBBcccccDDDDX"},
{"aaaaaBBBBBcccccDDDDDa", "aaaaaBBBBBcccccDDDDD"},
{"aaaaaBBBBBcccccDDDDD", "aaaaaBBBBBcccccDDDDDa"},
// Subcords
{subcord, subcord},
{subcord, "aaBBBBBccc"},
{subcord, "aaBBBBBccd"},
{subcord, "aaBBBBBccb"},
{subcord, "aaBBBBBxcb"},
{subcord, "aaBBBBBccca"},
{subcord, "aaBBBBBcc"},
// Concats
{concat, concat},
{concat,
"aaaaaaaaaaaaaaaaBBBBBBBBBBBBBBBBccccccccccccccccDDDDDDDDDDDDDDDD"},
{concat,
"aaaaaaaaaaaaaaaaBBBBBBBBBBBBBBBBcccccccccccccccxDDDDDDDDDDDDDDDD"},
{concat,
"aaaaaaaaaaaaaaaaBBBBBBBBBBBBBBBBacccccccccccccccDDDDDDDDDDDDDDDD"},
{concat,
"aaaaaaaaaaaaaaaaBBBBBBBBBBBBBBBBccccccccccccccccDDDDDDDDDDDDDDD"},
{concat,
"aaaaaaaaaaaaaaaaBBBBBBBBBBBBBBBBccccccccccccccccDDDDDDDDDDDDDDDDe"},
{concat, concat2},
}};
for (const auto& tc : test_cases) {
VerifyComparison(tc);
}
}
TEST(Cord, CompareAfterAssign) {
absl::Cord a("aaaaaa1111111");
absl::Cord b("aaaaaa2222222");
a = "cccccc";
b = "cccccc";
EXPECT_EQ(a, b);
EXPECT_FALSE(a < b);
a = "aaaa";
b = "bbbbb";
a = "";
b = "";
EXPECT_EQ(a, b);
EXPECT_FALSE(a < b);
}
// Test CompareTo() and ComparePrefix() against string and substring
// comparison methods from basic_string.
static void TestCompare(const absl::Cord& c, const absl::Cord& d,
RandomEngine* rng) {
typedef std::basic_string<uint8_t> ustring;
ustring cs(reinterpret_cast<const uint8_t*>(std::string(c).data()), c.size());
ustring ds(reinterpret_cast<const uint8_t*>(std::string(d).data()), d.size());
// ustring comparison is ideal because we expect Cord comparisons to be
// based on unsigned byte comparisons regardless of whether char is signed.
int expected = sign(cs.compare(ds));
EXPECT_EQ(expected, sign(c.Compare(d))) << c << ", " << d;
}
TEST(Compare, ComparisonIsUnsigned) {
RandomEngine rng(testing::GTEST_FLAG(random_seed));
std::uniform_int_distribution<uint32_t> uniform_uint8(0, 255);
char x = static_cast<char>(uniform_uint8(rng));
TestCompare(
absl::Cord(std::string(GetUniformRandomUpTo(&rng, 100), x)),
absl::Cord(std::string(GetUniformRandomUpTo(&rng, 100), x ^ 0x80)), &rng);
}
TEST(Compare, RandomComparisons) {
const int kIters = 5000;
RandomEngine rng(testing::GTEST_FLAG(random_seed));
int n = GetUniformRandomUpTo(&rng, 5000);
absl::Cord a[] = {MakeExternalCord(n),
absl::Cord("ant"),
absl::Cord("elephant"),
absl::Cord("giraffe"),
absl::Cord(std::string(GetUniformRandomUpTo(&rng, 100),
GetUniformRandomUpTo(&rng, 100))),
absl::Cord(""),
absl::Cord("x"),
absl::Cord("A"),
absl::Cord("B"),
absl::Cord("C")};
for (int i = 0; i < kIters; i++) {
absl::Cord c, d;
for (int j = 0; j < (i % 7) + 1; j++) {
c.Append(a[GetUniformRandomUpTo(&rng, ABSL_ARRAYSIZE(a))]);
d.Append(a[GetUniformRandomUpTo(&rng, ABSL_ARRAYSIZE(a))]);
}
std::bernoulli_distribution coin_flip(0.5);
TestCompare(coin_flip(rng) ? c : absl::Cord(std::string(c)),
coin_flip(rng) ? d : absl::Cord(std::string(d)), &rng);
}
}
template <typename T1, typename T2>
void CompareOperators() {
const T1 a("a");
const T2 b("b");
EXPECT_TRUE(a == a);
// For pointer type (i.e. `const char*`), operator== compares the address
// instead of the string, so `a == const char*("a")` isn't necessarily true.
EXPECT_TRUE(std::is_pointer<T1>::value || a == T1("a"));
EXPECT_TRUE(std::is_pointer<T2>::value || a == T2("a"));
EXPECT_FALSE(a == b);
EXPECT_TRUE(a != b);
EXPECT_FALSE(a != a);
EXPECT_TRUE(a < b);
EXPECT_FALSE(b < a);
EXPECT_TRUE(b > a);
EXPECT_FALSE(a > b);
EXPECT_TRUE(a >= a);
EXPECT_TRUE(b >= a);
EXPECT_FALSE(a >= b);