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Use FNV-1a from baselibs #807

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Merged
MaciejKaszynski merged 1 commit into from
Oct 20, 2026
+5 −31
Merged

Use FNV-1a from baselibs #807

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1 change: 1 addition & 0 deletions score/launch_manager/src/daemon/src/common/BUILD
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Original file line number Diff line number Diff line change
Expand Up @@ -35,6 +35,7 @@ cc_library(
include_prefix = "score/mw/launch_manager/common",
strip_include_prefix = "/score/launch_manager/src/daemon/src/common",
visibility = ["//score:__subpackages__"],
deps = ["@score_baselibs//score/language/futurecpp"],
)

lm_cc_test(
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35 changes: 4 additions & 31 deletions score/launch_manager/src/daemon/src/common/identifier_hash.cpp
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Expand Up @@ -12,6 +12,7 @@
********************************************************************************/

#include "score/mw/launch_manager/common/identifier_hash.hpp"
#include <score/hash.hpp>
#include <cstdint>
#include <mutex>
#include <unordered_map>
Expand Down Expand Up @@ -51,37 +52,9 @@ namespace score::mw::lifecycle
// - The probability of h(a) == h(b) for a != b should approach 1.0 / std::numeric_limits<std::size_t>::max().
// - This is small enough for initial implementation.

namespace
{

// Portable hash function FNV-1a https://www.rfc-editor.org/info/rfc9923/

#if SIZE_MAX == UINT32_MAX
constexpr std::size_t kFnvOffsetBasis = 2166136261U;
constexpr std::size_t kFnvPrime = 16777619U;
#elif SIZE_MAX == UINT64_MAX
constexpr std::size_t kFnvOffsetBasis = 14695981039346656037ULL;
constexpr std::size_t kFnvPrime = 1099511628211ULL;
#else
#error "FNV-1a constants are only defined here for 32-bit or 64-bit std::size_t"
#endif

std::size_t Fnv1aHash(std::string_view data) noexcept
{
std::size_t hash = kFnvOffsetBasis;
for (const unsigned char byte : data)
{
hash ^= static_cast<std::size_t>(byte);
hash *= kFnvPrime;
}
return hash;
}

} // namespace

IdentifierHash::IdentifierHash(std::string_view id)
{
hash_id_ = Fnv1aHash(id);
hash_id_ = score::cpp::hash_bytes_fnv1a<std::size_t>(id.data(), id.size());
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const std::lock_guard<std::mutex> lock(get_registry_mutex());
get_registry()[hash_id_] = id;
}
Expand All @@ -93,7 +66,7 @@ IdentifierHash::IdentifierHash(std::size_t hash_id)

std::optional<IdentifierHash> IdentifierHash::if_exists(std::string_view id)
{
const std::size_t hash_id = Fnv1aHash(id);
const std::size_t hash_id = score::cpp::hash_bytes_fnv1a<std::size_t>(id.data(), id.size());

const std::lock_guard<std::mutex> lock(get_registry_mutex());
const std::unordered_map<std::size_t, std::string>& registry = get_registry();
Expand Down Expand Up @@ -135,7 +108,7 @@ bool IdentifierHash::operator<(const IdentifierHash& other) const

IdentifierHash::IdentifierHash()
{
hash_id_ = Fnv1aHash(std::string_view(""));
hash_id_ = score::cpp::hash_bytes_fnv1a<std::size_t>("", 0U);
const std::lock_guard<std::mutex> lock(get_registry_mutex());
get_registry()[hash_id_] = "";
}
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