Hashmap

src/hashmap.c

@@ -1,6 +1,79 @@
+#ifdef ACL_LITTLE_ENDIAN
+#define LEFT_OR_RIGHT_SHIFT >>
+#else
+#ifdef ACL_BIG_ENDIAN
+#define LEFT_OR_RIGHT_SHIFT <<
+#else
+#error "endianiss not specified. make sure to properly add the cmake subdirectory."
+#endif
+#endif 
 #include <math.h>
-const unsigned acl_w = sizeof (unsigned) * 8;
-const unsigned acl_m = 9;
-unsigned hash(unsigned K) {
-	return (149695736*K) >> (acl_w-acl_m);
+#include <stddef.h>
+#include <stdlib.h>
+#include <acl/hashmap.h>
+#include <acl/array.h>
+#include <stdint.h>
+#include <string.h>
+
+size_t acl_hash(void *data, size_t dataSize, size_t bucketBits) {
+	switch(dataSize) {
+		case 1:
+			return (uint8_t)(101u * *(uint8_t*)data >> (8 - bucketBits));
+		case 2: {
+				uint16_t cache;
+				memcpy(&cache, data, 2);
+				return (uint16_t)(15227u * cache >> (16 - bucketBits));
+			}
+		case 3:
+		case 4: {
+				uint32_t cache = 0;
+				memcpy(&cache, data, dataSize);
+				return (uint32_t)(4000846301u * cache >> (32 - bucketBits));
+			}
+		default:
+			if(dataSize <= 8) {
+				 uint64_t cache = 0;
+				 memcpy(&cache, data, dataSize);
+				 return (uint64_t)(10223372036854775833u * cache >> (64 - bucketBits));
+			 }
+			uint8_t rest = (uintptr_t)data % sizeof(uint64_t);
+			size_t data_len = dataSize / sizeof(uint64_t);
+			uint8_t restEnd = dataSize % sizeof(uint64_t);
+			if(restEnd) ++data_len;
+			uint64_t *cache;
+			if(rest) {
+				cache = malloc(data_len * sizeof *cache);
+				memcpy(cache, data, dataSize);
+				cache[data_len - 1] = 0;
+			}
+			else cache = data;
+			uint64_t hash = 0;
+			for(size_t i = 0; i < data_len - 1; ++i) { 
+				hash ^= (uint64_t)(10223372036854775833u * cache[i]);
+			}
+				hash ^= (uint64_t)(10223372036854775833u * cache[data_len - 1] & (18446744073709551615u LEFT_OR_RIGHT_SHIFT (sizeof *cache - restEnd)));
+				free(cache);
+				return hash >> (64 - bucketBits);
+	}
+}
+union acl_hashmap_meta* acl_hashmap_create(size_t bucketCount, size_t sizeOneElement, size_t keySize) {
+	union acl_hashmap_meta *hashmap_meta = malloc(sizeof *hashmap_meta + bucketCount * sizeof(void*));
+	hashmap_meta->bucketCount = bucketCount;
+	hashmap_meta->sizeOneElement = sizeOneElement;
+	hashmap_meta->keyBits = log2(keySize);
+	void **hashmap_buckets = (void**)(hashmap_meta + 1);
+	for(size_t i; i < bucketCount; ++i) {
+		hashmap_buckets[i] = acl_arraylist_create(0, sizeOneElement);
+	}
+	return hashmap_meta;
+}
+
+void acl_hashmap_put(union acl_hashmap_meta *hashmap_meta, void *key, void *element) {
+	void **hashmap_buckets = (void**)(hashmap_meta + 1);
+
+}
+#include <stdio.h>
+int main() {
+	int baum[3] = {89, 120, 36};
+	printf("Hash: %lu\n", acl_hash(baum, 3 * sizeof *baum , 5));
 }