Data commit

Task/Hash-from-two-arrays/C/hash-from-two-arrays.c

@@ -0,0 +1,115 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define KeyType const char *
+#define ValType int
+
+#define HASH_SIZE 4096
+
+// hash function useful when KeyType is char * (string)
+unsigned strhashkey( const char * key, int max)
+{
+    unsigned h=0;
+    unsigned hl, hr;
+
+    while(*key) {
+        h += *key;
+        hl= 0x5C5 ^ (h&0xfff00000 )>>18;
+        hr =(h&0x000fffff );
+        h = hl ^ hr ^ *key++;
+    }
+    return h % max;
+}
+
+typedef struct sHme {
+    KeyType    key;
+    ValType    value;
+    struct sHme  *link;
+} *MapEntry;
+
+typedef struct he {
+    MapEntry  first, last;
+} HashElement;
+
+HashElement hash[HASH_SIZE];
+
+typedef void (*KeyCopyF)(KeyType *kdest, KeyType ksrc);
+typedef void (*ValCopyF)(ValType *vdest, ValType vsrc);
+typedef unsigned (*KeyHashF)( KeyType key, int upperBound );
+typedef int (*KeyCmprF)(KeyType key1, KeyType key2);
+
+void HashAddH( KeyType key, ValType value,
+        KeyCopyF copyKey, ValCopyF copyVal, KeyHashF hashKey, KeyCmprF keySame )
+{
+    unsigned hix = (*hashKey)(key, HASH_SIZE);
+    MapEntry m_ent;
+
+    for (m_ent= hash[hix].first;
+            m_ent && !(*keySame)(m_ent->key,key); m_ent=m_ent->link);
+    if (m_ent) {
+        (*copyVal)(&m_ent->value, value);
+    }
+    else {
+        MapEntry last;
+        MapEntry hme = malloc(sizeof(struct sHme));
+        (*copyKey)(&hme->key, key);
+        (*copyVal)(&hme->value, value);
+        hme->link = NULL;
+        last = hash[hix].last;
+        if (last) {
+//	    printf("Dup. hash key\n");
+            last->link = hme;
+        }
+        else
+            hash[hix].first = hme;
+        hash[hix].last = hme;
+    }
+}
+
+int HashGetH(ValType *val, KeyType key, KeyHashF hashKey, KeyCmprF keySame )
+{
+    unsigned hix = (*hashKey)(key, HASH_SIZE);
+    MapEntry m_ent;
+    for (m_ent= hash[hix].first;
+            m_ent && !(*keySame)(m_ent->key,key); m_ent=m_ent->link);
+    if (m_ent) {
+        *val = m_ent->value;
+    }
+    return (m_ent != NULL);
+}
+
+void copyStr(const char**dest, const char *src)
+{
+    *dest = strdup(src);
+}
+void copyInt( int *dest, int src)
+{
+    *dest = src;
+}
+int strCompare( const char *key1, const char *key2)
+{
+    return strcmp(key1, key2) == 0;
+}
+
+void HashAdd( KeyType key, ValType value )
+{
+    HashAddH( key, value, &copyStr, &copyInt, &strhashkey, &strCompare);
+}
+
+int HashGet(ValType *val, KeyType key)
+{
+    return HashGetH( val, key, &strhashkey, &strCompare);
+}
+
+int main()
+{
+    static const char * keyList[] = {"red","orange","yellow","green", "blue", "violet" };
+    static int valuList[] = {1,43,640, 747, 42, 42};
+    int ix;
+
+    for (ix=0; ix<6; ix++) {
+        HashAdd(keyList[ix], valuList[ix]);
+    }
+    return 0;
+}