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Support nulls in String compare, CreateSharedString (#5060)

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This commit is contained in:
Matt Frantz
2018-12-03 09:48:50 -08:00
committed by Wouter van Oortmerssen
parent 79cd55bd3a
commit 2aa0d9a54d
2 changed files with 64 additions and 3 deletions
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14
include/flatbuffers/flatbuffers.h
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@@ -344,6 +344,14 @@ template<typename T> static inline size_t VectorLength(const Vector<T> *v) {
return v ? v->Length() : 0;
}
// Lexicographically compare two strings (possibly containing nulls), and
// return true if the first is less than the second.
static inline bool StringLessThan(const char *a_data, uoffset_t a_size,
const char *b_data, uoffset_t b_size) {
const auto cmp = memcmp(a_data, b_data, (std::min)(a_size, b_size));
return cmp == 0 ? a_size < b_size : cmp < 0;
}
struct String : public Vector<char> {
const char *c_str() const { return reinterpret_cast<const char *>(Data()); }
std::string str() const { return std::string(c_str(), Length()); }
@@ -357,7 +365,7 @@ struct String : public Vector<char> {
// clang-format on
bool operator<(const String &o) const {
return strcmp(c_str(), o.c_str()) < 0;
return StringLessThan(this->data(), this->size(), o.data(), o.size());
}
};
@@ -1834,8 +1842,8 @@ protected:
bool operator()(const Offset<String> &a, const Offset<String> &b) const {
auto stra = reinterpret_cast<const String *>(buf_->data_at(a.o));
auto strb = reinterpret_cast<const String *>(buf_->data_at(b.o));
return strncmp(stra->c_str(), strb->c_str(),
(std::min)(stra->size(), strb->size()) + 1) < 0;
return StringLessThan(stra->data(), stra->size(),
strb->data(), strb->size());
}
const vector_downward *buf_;
};

53
tests/test.cpp
View File

@@ -2376,6 +2376,58 @@ void LoadVerifyBinaryTest() {
}
}
void CreateSharedStringTest() {
flatbuffers::FlatBufferBuilder builder;
const auto one1 = builder.CreateSharedString("one");
const auto two = builder.CreateSharedString("two");
const auto one2 = builder.CreateSharedString("one");
TEST_EQ(one1.o, one2.o);
const auto onetwo = builder.CreateSharedString("onetwo");
TEST_EQ(onetwo.o != one1.o, true);
TEST_EQ(onetwo.o != two.o, true);
// Support for embedded nulls
const char chars_b[] = {'a', '\0', 'b'};
const char chars_c[] = {'a', '\0', 'c'};
const auto null_b1 = builder.CreateSharedString(chars_b, sizeof(chars_b));
const auto null_c = builder.CreateSharedString(chars_c, sizeof(chars_c));
const auto null_b2 = builder.CreateSharedString(chars_b, sizeof(chars_b));
TEST_EQ(null_b1.o != null_c.o, true); // Issue#5058 repro
TEST_EQ(null_b1.o, null_b2.o);
// Put the strings into an array for round trip verification.
const flatbuffers::Offset<flatbuffers::String> array[7] = { one1, two, one2, onetwo, null_b1, null_c, null_b2 };
const auto vector_offset = builder.CreateVector(array, flatbuffers::uoffset_t(7));
MonsterBuilder monster_builder(builder);
monster_builder.add_name(two);
monster_builder.add_testarrayofstring(vector_offset);
builder.Finish(monster_builder.Finish());
// Read the Monster back.
const auto *monster = flatbuffers::GetRoot<Monster>(builder.GetBufferPointer());
TEST_EQ_STR(monster->name()->c_str(), "two");
const auto *testarrayofstring = monster->testarrayofstring();
TEST_EQ(testarrayofstring->size(), flatbuffers::uoffset_t(7));
const auto &a = *testarrayofstring;
TEST_EQ_STR(a[0]->c_str(), "one");
TEST_EQ_STR(a[1]->c_str(), "two");
TEST_EQ_STR(a[2]->c_str(), "one");
TEST_EQ_STR(a[3]->c_str(), "onetwo");
TEST_EQ(a[4]->str(), (std::string(chars_b, sizeof(chars_b))));
TEST_EQ(a[5]->str(), (std::string(chars_c, sizeof(chars_c))));
TEST_EQ(a[6]->str(), (std::string(chars_b, sizeof(chars_b))));
// Make sure String::operator< works, too, since it is related to StringOffsetCompare.
TEST_EQ((*a[0]) < (*a[1]), true);
TEST_EQ((*a[1]) < (*a[0]), false);
TEST_EQ((*a[1]) < (*a[2]), false);
TEST_EQ((*a[2]) < (*a[1]), true);
TEST_EQ((*a[4]) < (*a[3]), true);
TEST_EQ((*a[5]) < (*a[4]), false);
TEST_EQ((*a[5]) < (*a[4]), false);
TEST_EQ((*a[6]) < (*a[5]), true);
}
int FlatBufferTests() {
// clang-format off
#if defined(FLATBUFFERS_MEMORY_LEAK_TRACKING) && \
@@ -2445,6 +2497,7 @@ int FlatBufferTests() {
ParseProtoBufAsciiTest();
TypeAliasesTest();
EndianSwapTest();
CreateSharedStringTest();
JsonDefaultTest();
FlexBuffersTest();
UninitializedVectorTest();