More work on hashing

asl/buffer.hpp

@@ -389,6 +389,12 @@ public:
         ASL_ASSERT(i >= 0 && i <= size());
         return data()[i];
     }
+
+    template<typename H>
+    friend H AslHashValue(H h, const buffer& b)
+    {
+        return H::combine_contiguous(ASL_MOVE(h), b.as_span());
+    }
 };
 
 } // namespace asl

asl/hash.hpp

@@ -68,14 +68,27 @@ struct HashState
     constexpr HashState() = default;
     explicit constexpr HashState(uint128_t s) : state{s} {}
 
-    static HashState combine_bytes(HashState h, span<const byte> bytes)
+    template<typename T>
+    static HashState combine_contiguous(HashState h, span<const T> s)
     {
+        if constexpr (uniquely_represented<T>)
+        {
+            auto bytes = as_bytes(s);
             auto hashed = city_hash::CityHash128WithSeed(
                 reinterpret_cast<const char*>(bytes.data()),
                 static_cast<size_t>(bytes.size()),
                 h.state);
             return HashState{hashed};
         }
+        else
+        {
+            for (const auto& value: s)
+            {
+                h = AslHashValue(ASL_MOVE(h), value);
+            }
+            return h;
+        }
+    }
 
     static constexpr HashState combine(HashState h)
     {
@@ -85,7 +98,7 @@ struct HashState
     template<hashable_generic<HashState> Arg, hashable_generic<HashState>... Remaining>
     static constexpr HashState combine(HashState h, const Arg& arg, const Remaining&... remaining)
     {
-        return combine(AslHashValue(h, arg), remaining...);
+        return combine(AslHashValue(ASL_MOVE(h), arg), remaining...);
     }
 };
 
@@ -95,15 +108,18 @@ concept hashable = hashable_generic<T, HashState>;
 template<typename H, uniquely_represented T>
 constexpr H AslHashValue(H h, const T& value)
 {
-    return H::combine_bytes(h, as_bytes(span<const T>{&value, 1}));
+    return H::combine_contiguous(ASL_MOVE(h), span<const T>{&value, 1});
 }
 
 template<typename H>
 constexpr H AslHashValue(H h, bool value)
 {
-    return AslHashValue(h, value ? 1 : 0);
+    return AslHashValue(ASL_MOVE(h), value ? 1 : 0);
 }
 
+template<typename H, typename T>
+constexpr void AslHashValue(H h, T*); // Don't hash pointers
+
 template<hashable T>
 constexpr uint64_t hash_value(const T& value)
 {

asl/meta.hpp

@@ -189,8 +189,11 @@ template<>           struct _is_integer_helper<uint64_t> : true_type  {};
 
 template<typename T> concept is_integer = _is_integer_helper<un_cv_t<T>>::value;
 
+template<typename T> concept is_enum = __is_enum(T);
+
 template<typename T> struct is_uniquely_represented : false_type {};
 template<is_integer T> struct is_uniquely_represented<T> : true_type {};
+template<is_enum T> struct is_uniquely_represented<T> : true_type {};
 template<> struct is_uniquely_represented<uint128_t> : true_type {};
 template<> struct is_uniquely_represented<byte> : true_type {};
 

asl/span.hpp

@@ -171,6 +171,12 @@ public:
         ASL_ASSERT(sub_size >= 0 && sub_size <= size());
         return span<T>{ data() + size() - sub_size, sub_size };
     }
+
+    template<typename H>
+    friend H AslHashValue(H h, const span& s)
+    {
+        return H::combine_contiguous(ASL_MOVE(h), span<const T>{s.data(), s.size()});
+    }
 };
 
 template<is_object T, isize_t kSize>

asl/string_view.hpp

@@ -89,7 +89,7 @@ public:
     template<typename H>
     friend H AslHashValue(H h, string_view sv)
     {
-        return H::combine(H::combine_bytes(h, as_bytes(sv.as_span())), sv.size());
+        return H::combine(H::combine_contiguous(h, as_bytes(sv.as_span())), sv.size());
     }
 };
 

asl/tests/hash_tests.cpp

@@ -2,6 +2,11 @@
 #include "asl/hash.hpp"
 #include "asl/string_view.hpp"
 #include "asl/string.hpp"
+#include "asl/buffer.hpp"
+
+static_assert(!asl::hashable<int*>);
+static_assert(!asl::hashable<int[]>);
+static_assert(!asl::hashable<int[9]>);
 
 static_assert(asl::hashable<uint8_t>);
 static_assert(asl::hashable<uint16_t>);
@@ -51,8 +56,87 @@ ASL_TEST(strings)
     ASL_TEST_EXPECT(asl::hash_value("hello"_sv) == asl::hash_value(asl::string("hello"_sv)));
 }
 
-// @Todo span, buffer (add combine_contiguous (optimize uniquely_represented))
+static_assert(asl::hashable<asl::span<const int>>);
-// @Todo enum classes
+static_assert(asl::hashable<asl::span<asl::string_view>>);
+
+ASL_TEST(span)
+{
+    int ints1[] = {1, 2, 3};
+    int ints2[] = {1, 2, 3};
+    int ints3[] = {1, 2};
+    int ints4[] = {3, 2, 1};
+
+    ASL_TEST_EXPECT(asl::hash_value(asl::span<int>(ints1)) == asl::hash_value(asl::span<int>(ints2)));
+    ASL_TEST_EXPECT(asl::hash_value(asl::span<int>(ints1)) != asl::hash_value(asl::span<int>(ints3)));
+    ASL_TEST_EXPECT(asl::hash_value(asl::span<int>(ints1)) != asl::hash_value(asl::span<int>(ints4)));
+
+    asl::string_view strs1[] = {"a", "abc", "hello"};
+    asl::string_view strs2[] = {"a", "abc", "hello"};
+    asl::string_view strs3[] = {"a", "abc"};
+    asl::string_view strs4[] = {"a", "abc", "hello", "what"};
+
+    ASL_TEST_EXPECT(asl::hash_value(asl::span<asl::string_view>(strs1)) == asl::hash_value(asl::span<asl::string_view>(strs2)));
+    ASL_TEST_EXPECT(asl::hash_value(asl::span<asl::string_view>(strs1)) != asl::hash_value(asl::span<asl::string_view>(strs3)));
+    ASL_TEST_EXPECT(asl::hash_value(asl::span<asl::string_view>(strs1)) != asl::hash_value(asl::span<asl::string_view>(strs4)));
+}
+
+static_assert(asl::hashable<asl::buffer<int>>);
+
+ASL_TEST(buffer)
+{
+    asl::buffer<int> ints1;
+    ints1.push(1);
+    ints1.push(2);
+    ints1.push(3);
+    
+    asl::buffer<int> ints2;
+    ints2.push(1);
+    ints2.push(2);
+    ints2.push(3);
+    
+    asl::buffer<int> ints3;
+    ints3.push(1);
+    ints3.push(2);
+    
+    asl::buffer<int> ints4;
+    ints4.push(1);
+    ints4.push(2);
+    ints4.push(4);
+
+    ASL_TEST_EXPECT(asl::hash_value(ints1) == asl::hash_value(ints2));
+    ASL_TEST_EXPECT(asl::hash_value(ints1) != asl::hash_value(ints3));
+    ASL_TEST_EXPECT(asl::hash_value(ints1) != asl::hash_value(ints4));
+    ASL_TEST_EXPECT(asl::hash_value(ints1) == asl::hash_value(ints1.as_span()));
+
+    asl::buffer<asl::string_view> strs1;
+    strs1.push("Hello");
+    strs1.push("World");
+    
+    asl::buffer<asl::string_view> strs2;
+    strs2.push("Hello");
+    strs2.push("World");
+    
+    asl::buffer<asl::string_view> strs3;
+    strs3.push("Hello");
+    strs3.push("world");
+    
+    asl::buffer<asl::string_view> strs4;
+    strs4.push("Hello");
+    strs4.push("World");
+    strs4.push("World");
+
+    ASL_TEST_EXPECT(asl::hash_value(strs1) == asl::hash_value(strs2));
+    ASL_TEST_EXPECT(asl::hash_value(strs1) != asl::hash_value(strs3));
+    ASL_TEST_EXPECT(asl::hash_value(strs1) != asl::hash_value(strs4));
+    ASL_TEST_EXPECT(asl::hash_value(strs1) == asl::hash_value(strs1.as_span()));
+}
+
+enum Enum1 {};
+enum class Enum2 {};
+
+static_assert(asl::hashable<Enum1>);
+static_assert(asl::hashable<Enum2>);
+
 // @Todo option (optimize uniquely_represented + has_niche)
 // @Todo status, status_or
 // @Todo box

asl/tests/meta_tests.cpp

@@ -236,3 +236,14 @@ static_assert(!asl::is_floating_point<C>);
 static_assert(asl::uniquely_represented<int>);
 static_assert(asl::uniquely_represented<uint128_t>);
 static_assert(!asl::uniquely_represented<bool>);
+
+enum Enum1 {};
+enum class Enum2 {};
+
+static_assert(asl::uniquely_represented<Enum1>);
+static_assert(asl::uniquely_represented<Enum2>);
+
+static_assert(!asl::is_enum<int>);
+static_assert(asl::is_enum<Enum1>);
+static_assert(asl::is_enum<Enum2>);
+