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#include "Globals.h"
#include "BlockState.h"
BlockState::BlockState():
mChecksum(initializeChecksum())
{
// Nothing needed yet
}
BlockState::BlockState(const AString & aKey, const AString & aValue):
mState({{aKey, aValue}}),
mChecksum(initializeChecksum())
{
}
BlockState::BlockState(std::initializer_list<std::pair<const AString, AString>> aKeysAndValues):
mState(aKeysAndValues),
mChecksum(initializeChecksum())
{
}
BlockState::BlockState(const std::map<AString, AString> & aKeysAndValues):
mState(aKeysAndValues),
mChecksum(initializeChecksum())
{
}
BlockState::BlockState(std::map<AString, AString> && aKeysAndValues):
mState(std::move(aKeysAndValues)),
mChecksum(initializeChecksum())
{
}
BlockState::BlockState(const BlockState & aCopyFrom, std::initializer_list<std::pair<const AString, AString>> aAdditionalKeysAndValues):
mState(aCopyFrom.mState)
{
for (const auto & kav: aAdditionalKeysAndValues)
{
mState[kav.first] = kav.second;
}
mChecksum = initializeChecksum();
}
BlockState::BlockState(const BlockState & aCopyFrom, const std::map<AString, AString> & aAdditionalKeysAndValues):
mState(aCopyFrom.mState)
{
for (const auto & kav: aAdditionalKeysAndValues)
{
mState[kav.first] = kav.second;
}
mChecksum = initializeChecksum();
}
bool BlockState::operator <(const BlockState & aOther) const
{
// Fast-return this using checksum
if (mChecksum != aOther.mChecksum)
{
return (mChecksum < aOther.mChecksum);
}
// Can fast-return this due to how comparison works
if (mState.size() != aOther.mState.size())
{
return (mState.size() < aOther.mState.size());
}
auto itA = mState.begin();
auto itOther = aOther.mState.begin();
// don't need to check itOther, size checks above ensure size(A) == size(O)
while (itA != mState.end())
{
{
const auto cmp = itA->first.compare(itOther->first);
if (cmp != 0)
{
return (cmp < 0);
}
}
{
const auto cmp = itA->second.compare(itOther->second);
if (cmp != 0)
{
return (cmp < 0);
}
}
++itA;
++itOther;
}
return false;
}
bool BlockState::operator ==(const BlockState & aOther) const
{
// Fast-fail if the checksums differ or differrent counts:
if ((mChecksum != aOther.mChecksum) || (mState.size() != aOther.mState.size()))
{
return false;
}
// Slow-check everything if the checksums match:
return std::equal(mState.begin(), mState.end(), aOther.mState.begin());
}
const AString & BlockState::value(const AString & aKey) const
{
auto itr = mState.find(aKey);
if (itr == mState.end())
{
static AString empty;
return empty;
}
return itr->second;
}
UInt32 BlockState::initializeChecksum()
{
removeEmptyKeys();
// Calculate the checksum as a XOR of all mState keys' and values' checksums
// This way we don't depend on the std::map's ordering
UInt32 res = 0;
for (const auto & kv: mState)
{
auto partial = partialChecksum(kv.first) ^ partialChecksum(kv.second);
res = res ^ partial;
}
return res;
}
void BlockState::removeEmptyKeys()
{
for (auto itr = mState.begin(); itr != mState.end();)
{
if (itr->second.empty())
{
itr = mState.erase(itr);
}
else
{
++itr;
}
}
}
UInt32 BlockState::partialChecksum(const AString & aString)
{
UInt32 shift = 0;
UInt32 res = 0;
for (auto ch: aString)
{
UInt32 v = static_cast<UInt8>(ch);
v = v << shift;
shift = (shift + 1) % 24;
res = res ^ v;
}
return res;
}
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