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Unconditionally use FindFirstBit in SetBitIterator

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Add simple tests
This commit is contained in:
Jonathan G Rennison
2024-01-25 19:03:32 +00:00
parent 5404be172c
commit c26ca5369e
2 changed files with 21 additions and 21 deletions
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23
src/core/bitmath_func.hpp
View File

@@ -322,11 +322,7 @@ struct SetBitIterator {
bool operator==(const Iterator &other) const bool operator==(const Iterator &other) const
{ {
#ifdef WITH_BITMATH_BUILTINS
return this->bitset == other.bitset; return this->bitset == other.bitset;
#else
return this->bitset == other.bitset && (this->bitset == 0 || this->bitpos == other.bitpos);
#endif
} }
bool operator!=(const Iterator &other) const { return !(*this == other); } bool operator!=(const Iterator &other) const { return !(*this == other); }
Tbitpos operator*() const { return this->bitpos; } Tbitpos operator*() const { return this->bitpos; }
@@ -337,29 +333,14 @@ struct SetBitIterator {
Tbitpos bitpos; Tbitpos bitpos;
void Validate() void Validate()
{ {
#ifdef WITH_BITMATH_BUILTINS
if (this->bitset != 0) { if (this->bitset != 0) {
typename std::make_unsigned<Tbitset>::type unsigned_value = this->bitset; typename std::make_unsigned<Tbitset>::type unsigned_value = this->bitset;
if (sizeof(Tbitset) <= sizeof(unsigned int)) { this->bitpos = static_cast<Tbitpos>(FindFirstBit(unsigned_value));
bitpos = static_cast<Tbitpos>(__builtin_ctz(unsigned_value));
} else if (sizeof(Tbitset) == sizeof(unsigned long)) {
bitpos = static_cast<Tbitpos>(__builtin_ctzl(unsigned_value));
} else {
bitpos = static_cast<Tbitpos>(__builtin_ctzll(unsigned_value));
}
} }
#else
while (this->bitset != 0 && (this->bitset & 1) == 0) this->Next();
#endif
} }
void Next() void Next()
{ {
#ifdef WITH_BITMATH_BUILTINS this->bitset = KillFirstBit(this->bitset);
this->bitset = static_cast<Tbitset>(this->bitset ^ (this->bitset & -this->bitset));
#else
this->bitset = static_cast<Tbitset>(this->bitset >> 1);
this->bitpos++;
#endif
} }
}; };

19
src/tests/bitmath_func.cpp
View File

@@ -51,3 +51,22 @@ TEST_CASE("FindLastBit tests")
CHECK(FindLastBit(0x42U) == FindLastBit(0x40U)); CHECK(FindLastBit(0x42U) == FindLastBit(0x40U));
CHECK(FindLastBit(0xAAAAU) == FindLastBit(0x8000U)); CHECK(FindLastBit(0xAAAAU) == FindLastBit(0x8000U));
} }
TEST_CASE("SetBitIterator tests")
{
auto test_case = [&](auto input, std::initializer_list<uint> expected) {
auto iter = expected.begin();
for (auto bit : SetBitIterator(input)) {
if (iter == expected.end()) return false;
if (bit != *iter) return false;
++iter;
}
return iter == expected.end();
};
CHECK(test_case(0, {}));
CHECK(test_case(1, { 0 }));
CHECK(test_case(42, { 1, 3, 5 }));
CHECK(test_case(0x8080FFFFU, { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 23, 31 }));
CHECK(test_case(INT32_MIN, { 31 }));
CHECK(test_case(INT64_MIN, { 63 }));
}