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foundationdb
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Avoid memcpy for small types 

This is undefined behavior, since it's potentially a misaligned access.
But it's _probably_ not worse than the status quo
This commit is contained in:
Andrew Noyes 2019-07-29 17:11:45 -07:00
parent 438b20bc30
commit 9f32edf4df
2 changed files with 3 additions and 3 deletions
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4
fdbclient/FDBTypes.h
View File

@ -331,12 +331,12 @@ struct string_serialized_traits<KeyValueRef> : std::true_type {
uint32_t save(uint8_t* out, const KeyValueRef& item) const {
auto begin = out;
uint32_t sz = item.key.size();
memcpy(out, &sz, sizeof(sz));
*reinterpret_cast<decltype(sz)*>(out) = sz;
out += sizeof(sz);
memcpy(out, item.key.begin(), sz);
out += sz;
sz = item.value.size();
memcpy(out, &sz, sizeof(sz));
*reinterpret_cast<decltype(sz)*>(out) = sz;
out += sizeof(sz);
memcpy(out, item.value.begin(), sz);
out += sz;

2
flow/Arena.h
View File

@ -1143,7 +1143,7 @@ struct dynamic_size_traits<VectorRef<V, VecSerStrategy::String>> : std::true_typ
string_serialized_traits<V> traits;
auto* p = out;
uint32_t length = t.size();
memcpy(out, &length, sizeof(length));
*reinterpret_cast<decltype(length)*>(out) = length;
out += sizeof(length);
for (const auto& item : t) {
out += traits.save(out, item);