a

2 files changed, 57 insertions, 35 deletions

diff --git a/compat/int-hash.cpp b/compat/int-hash.cpp
index 5847e284..aa5287f8 100644
--- a/compat/int-hash.cpp
+++ b/compat/int-hash.cpp
@@ -6,72 +6,88 @@ namespace floormat {
 
 namespace {
 
+template<typename T> struct fnvhash_params;
+
+template<> struct fnvhash_params<uint32_t> { uint32_t a = 0x811c9dc5u, b = 0x01000193u; };
+template<> struct fnvhash_params<uint64_t> { uint64_t a = 0xcbf29ce484222325u, b = 0x100000001b3u; };
+
 [[maybe_unused]]
-CORRADE_ALWAYS_INLINE uint32_t FNVHash_32(uint32_t x)
+CORRADE_ALWAYS_INLINE size_t fnvhash_uint_32(uint32_t x)
 {
-    const auto *str = (const char*)&x, *end = str + 4;
-    uint32_t hash = 0x811c9dc5u;
-fm_UNROLL_4
-    for (; str != end; ++str)
-    {
-        hash *= 0x01000193u;
-        hash ^= (uint8_t)*str;
-    }
+    constexpr auto params = fnvhash_params<std::common_type_t<size_t>>{};
+    constexpr auto a = params.a, b = params.b;
+    auto hash = a;
+    const auto* str = (const char*)&x;
+
+    hash *= b; hash ^= (uint8_t)*str++; // 0
+    hash *= b; hash ^= (uint8_t)*str++; // 1
+    hash *= b; hash ^= (uint8_t)*str++; // 2
+    hash *= b; hash ^= (uint8_t)*str++; // 3
+
     return hash;
 }
 
-CORRADE_ALWAYS_INLINE uint64_t FNVHash_64(uint64_t x)
+CORRADE_ALWAYS_INLINE size_t fnvhash_uint_64(uint64_t x)
 {
-    const auto *str = (const char*)&x, *end = str + 8;
-    uint64_t hash = 0xcbf29ce484222325u;
-fm_UNROLL_8
-    for (; str != end; ++str)
-    {
-        hash *= 0x100000001b3u;
-        hash ^= (uint8_t)*str;
-    }
+    constexpr auto params = fnvhash_params<std::common_type_t<size_t>>{};
+    constexpr auto a = params.a, b = params.b;
+    auto hash = a;
+    const auto* str = (const char*)&x;
+
+    hash *= b; hash ^= (uint8_t)*str++; // 0
+    hash *= b; hash ^= (uint8_t)*str++; // 1
+    hash *= b; hash ^= (uint8_t)*str++; // 2
+    hash *= b; hash ^= (uint8_t)*str++; // 3
+    hash *= b; hash ^= (uint8_t)*str++; // 4
+    hash *= b; hash ^= (uint8_t)*str++; // 5
+    hash *= b; hash ^= (uint8_t)*str++; // 6
+    hash *= b; hash ^= (uint8_t)*str++; // 7
+
     return hash;
 }
 
 } // namespace
 
-uint64_t fnvhash_32(const void* buf, size_t size)
+uint32_t hash_32(const void* buf, size_t size) noexcept
 {
+    constexpr auto params = fnvhash_params<std::common_type_t<uint32_t>>{};
+    constexpr auto a = params.a, b = params.b;
+    auto hash = a;
     const auto *str = (const char*)buf, *const end = str + size;
-    uint32_t hash = 0x811c9dc5u;
+
 fm_UNROLL_4
     for (; str != end; ++str)
     {
-        hash *= 0x01000193u;
+        hash *= b;
         hash ^= (uint8_t)*str;
     }
     return hash;
 }
 
-uint64_t fnvhash_64(const void* buf, size_t size)
+uint64_t hash_64(const void* buf, size_t size) noexcept
 {
+    constexpr auto params = fnvhash_params<std::common_type_t<size_t>>{};
+    constexpr auto a = params.a, b = params.b;
+    auto hash = a;
     const auto *str = (const char*)buf, *const end = str + size;
-    uint64_t hash = 0xcbf29ce484222325u;
+
 fm_UNROLL_8
     for (; str != end; ++str)
     {
-        hash *= 0x100000001b3u;
+        hash *= b;
         hash ^= (uint8_t)*str;
     }
     return hash;
 }
 
-size_t int_hash(uint32_t x) noexcept
+size_t hash_int(uint32_t x) noexcept
 {
-    if constexpr(sizeof(size_t) == 4)
-        return FNVHash_32(x);
-    else
-        return FNVHash_64(x);
+    return fnvhash_uint_32(x);
 }
 
-size_t int_hash(uint64_t x) noexcept
+size_t hash_int(uint64_t x) noexcept
 {
-    return FNVHash_64(x);
+    return fnvhash_uint_64(x);
 }
 
 } // namespace floormat
diff --git a/compat/int-hash.hpp b/compat/int-hash.hpp
index 86fc6a45..b3dd7616 100644
--- a/compat/int-hash.hpp
+++ b/compat/int-hash.hpp
@@ -1,11 +1,17 @@
 #pragma once
 
+namespace floormat::impl_hash {
+
+template<size_t N> size_t hash_buf(const void* buf, size_t size) noexcept = delete;
+
+} // namespace floormat::impl_hash
+
 namespace floormat {
 
-size_t int_hash(uint32_t x) noexcept;
-size_t int_hash(uint64_t x) noexcept;
+uint64_t hash_64(const void* buf, size_t size) noexcept;
+uint32_t hash_32(const void* buf, size_t size) noexcept;
 
-uint64_t fnvhash_64(const void* buf, size_t size);
-uint64_t fnvhash_32(const void* buf, size_t size);
+size_t hash_int(uint32_t x) noexcept;
+size_t hash_int(uint64_t x) noexcept;
 
 } // namespace floormat