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Modernize Hash ordering with C++20 <=>

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Progress on #10832

This doesn't switch to auto-deriving the fields, but by defining `<=>`
we allow deriving `<=>` in downstream types where `Hash` is used.
This commit is contained in:
John Ericson 2024-05-16 18:46:38 -04:00
parent d16fcaee21
commit cfc18a7739
2 changed files with 8 additions and 20 deletions
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17
src/libutil/hash.cc
View file

@ -50,21 +50,14 @@ bool Hash::operator == (const Hash & h2) const
} }
bool Hash::operator != (const Hash & h2) const std::strong_ordering Hash::operator <=> (const Hash & h) const
{ {
return !(*this == h2); if (auto cmp = algo <=> h.algo; cmp != 0) return cmp;
} if (auto cmp = hashSize <=> h.hashSize; cmp != 0) return cmp;
bool Hash::operator < (const Hash & h) const
{
if (hashSize < h.hashSize) return true;
if (hashSize > h.hashSize) return false;
for (unsigned int i = 0; i < hashSize; i++) { for (unsigned int i = 0; i < hashSize; i++) {
if (hash[i] < h.hash[i]) return true; if (auto cmp = hash[i] <=> h.hash[i]; cmp != 0) return cmp;
if (hash[i] > h.hash[i]) return false;
} }
return false; return std::strong_ordering::equivalent;
} }

11
src/libutil/hash.hh
View file

@ -86,19 +86,14 @@ private:
public: public:
/** /**
* Check whether two hash are equal. * Check whether two hashes are equal.
*/ */
bool operator == (const Hash & h2) const; bool operator == (const Hash & h2) const;
/** /**
* Check whether two hash are not equal. * Compare how two hashes are ordered.
*/ */
bool operator != (const Hash & h2) const; std::strong_ordering operator <=> (const Hash & h2) const;
/**
* For sorting.
*/
bool operator < (const Hash & h) const;
/** /**
* Returns the length of a base-16 representation of this hash. * Returns the length of a base-16 representation of this hash.