add `cpy310_tuplehash`

include/pocketpy/common/algorithm.h

@@ -1,6 +1,7 @@
 #pragma once
 
 #include <stdbool.h>
+#include <stdint.h>
 
 #define c11__less(a, b) ((a) < (b))
 
@@ -38,3 +39,5 @@ bool c11__stable_sort(void* ptr,
                       int elem_size,
                       int (*f_lt)(const void* a, const void* b, void* extra),
                       void* extra);
+
+uint64_t cpy310_tuplehash(uint64_t* p, int len);

src/common/algorithm.c

@@ -54,3 +54,42 @@ bool c11__stable_sort(void* ptr_,
     free(tmp);
     return true;
 }
+
+/* Hash Functions */
+
+// https://github.com/python/cpython/blob/v3.10.15/Objects/tupleobject.c#L406
+#define SIZEOF_PY_UHASH_T 8
+typedef uint64_t Py_uhash_t;
+
+#if SIZEOF_PY_UHASH_T > 4
+#define _PyHASH_XXPRIME_1 ((Py_uhash_t)11400714785074694791ULL)
+#define _PyHASH_XXPRIME_2 ((Py_uhash_t)14029467366897019727ULL)
+#define _PyHASH_XXPRIME_5 ((Py_uhash_t)2870177450012600261ULL)
+#define _PyHASH_XXROTATE(x) ((x << 31) | (x >> 33))  /* Rotate left 31 bits */
+#else
+#define _PyHASH_XXPRIME_1 ((Py_uhash_t)2654435761UL)
+#define _PyHASH_XXPRIME_2 ((Py_uhash_t)2246822519UL)
+#define _PyHASH_XXPRIME_5 ((Py_uhash_t)374761393UL)
+#define _PyHASH_XXROTATE(x) ((x << 13) | (x >> 19))  /* Rotate left 13 bits */
+#endif
+
+uint64_t cpy310_tuplehash(uint64_t* p, int len){
+    Py_uhash_t acc = _PyHASH_XXPRIME_5;
+    for (int i = 0; i < len; i++) {
+        Py_uhash_t lane = p[i];
+        if (lane == (Py_uhash_t)-1) {
+            return -1;
+        }
+        acc += lane * _PyHASH_XXPRIME_2;
+        acc = _PyHASH_XXROTATE(acc);
+        acc *= _PyHASH_XXPRIME_1;
+    }
+
+    /* Add input length, mangled to keep the historical value of hash(()). */
+    acc += len ^ (_PyHASH_XXPRIME_5 ^ 3527539UL);
+
+    if (acc == (Py_uhash_t)-1) {
+        return 1546275796;
+    }
+    return acc;
+}

src/modules/linalg.c

@@ -306,7 +306,8 @@ DEF_VECTOR_INT_OPS(3)
 static bool vec2i__hash__(int argc, py_Ref argv) {
     PY_CHECK_ARGC(1);
     c11_vec2i v = py_tovec2i(argv);
-    uint64_t hash = ((uint64_t)v.x << 32) | (uint64_t)v.y;
+    uint64_t values[2] = {v.x, v.y};
+    uint64_t hash = cpy310_tuplehash(values, 2);
     py_newint(py_retval(), (py_i64)hash);
     return true;
 }
@@ -314,10 +315,8 @@ static bool vec2i__hash__(int argc, py_Ref argv) {
 static bool vec3i__hash__(int argc, py_Ref argv) {
     PY_CHECK_ARGC(1);
     c11_vec3i v = py_tovec3i(argv);
-    uint64_t x_part = (uint64_t)(v.x & 0xFFFFFF);
-    uint64_t y_part = (uint64_t)(v.y & 0xFFFFFF);
-    uint64_t z_part = (uint64_t)(v.z & 0xFFFF);
-    uint64_t hash = (x_part << 40) | (y_part << 16) | z_part;
+    uint64_t values[3] = {v.x, v.y, v.z};
+    uint64_t hash = cpy310_tuplehash(values, 3);
     py_newint(py_retval(), (py_i64)hash);
     return true;
 }

src/public/py_tuple.c

@@ -155,14 +155,19 @@ static bool tuple__hash__(int argc, py_Ref argv) {
     PY_CHECK_ARGC(1);
     int length = py_tuple_len(argv);
     py_TValue* data = py_tuple_data(argv);
-    uint64_t x = 1000003;
+    uint64_t __buffer[8];
+    uint64_t* p = length <= 8 ? __buffer : malloc(sizeof(uint64_t) * length);
     for(int i = 0; i < length; i++) {
-        py_i64 y;
-        if(!py_hash(&data[i], &y)) return false;
-        // recommended by Github Copilot
-        x = x ^ (y + 0x9e3779b9 + (x << 6) + (x >> 2));
+        py_i64 x;
+        if(!py_hash(&data[i], &x)) {
+            if(p != __buffer) free(p);
+            return false;
+        }
+        p[i] = x;
     }
-    py_newint(py_retval(), x);
+    uint64_t hash = cpy310_tuplehash(p, length);
+    if(p != __buffer) free(p);
+    py_newint(py_retval(), (py_i64)hash);
     return true;
 }