feat: add hmapHashString and hmapInit

src/hmap.c

@@ -0,0 +1,123 @@
+#include "hmap.h"
+#include "heap.h"
+#include "string.h"
+#include "klib.h"
+
+uint64 hmapHashString(const char* key)
+{
+    uint64 hash = 1469598103934665603UL; /* FNV-1a 64-bit offset basis */
+    for (const unsigned char* p = (const unsigned char*)key; *p; p++) {
+        hash ^= (uint64)*p;
+        hash *= 1099511628211UL; /* FNV-1a 64-bit prime */
+    }
+    return hash;
+}
+
+bool hmapInit(Hmap* h, usize bucketCount)
+{
+    if (bucketCount == 0)
+        bucketCount = 16;
+
+    h->buckets = (HmapEntry**)kmalloc(bucketCount * sizeof(HmapEntry*));
+    if (!h->buckets)
+        return false;
+
+    for (usize i = 0; i < bucketCount; i++)
+        h->buckets[i] = nullptr;
+    h->bucketCount = bucketCount;
+    h->count = 0;
+    return true;
+}
+
+void hmapFree(Hmap* h)
+{
+    for (usize i = 0; i < h->bucketCount; i++) {
+        HmapEntry* entry = h->buckets[i];
+        while (entry) {
+            HmapEntry* next = entry->next;
+            kfree(entry->key);
+            kfree(entry);
+            entry = next;
+        }
+    }
+    kfree(h->buckets);
+    h->buckets = nullptr;
+    h->bucketCount = 0;
+    h->count = 0;
+}
+
+static HmapEntry** findSlot(const Hmap* h, const char* key)
+{
+    usize bucket = hmapHashString(key) % h->bucketCount;
+    HmapEntry** slot = &h->buckets[bucket];
+    while (*slot && strcmp((*slot)->key, key) != 0)
+        slot = &(*slot)->next;
+    return slot;
+}
+
+bool hmapSet(Hmap* h, const char* key, void* value)
+{
+    HmapEntry** slot = findSlot(h, key);
+    if (*slot) {
+        (*slot)->value = value;
+        return true;
+    }
+
+    HmapEntry* entry = (HmapEntry*)kmalloc(sizeof(HmapEntry));
+    if (!entry)
+        return false;
+
+    usize keyLen = strlen(key);
+    entry->key = (char*)kmalloc(keyLen + 1);
+    if (!entry->key) {
+        kfree(entry);
+        return false;
+    }
+    strcpy(entry->key, key);
+    entry->value = value;
+    entry->next = nullptr;
+
+    *slot = entry;
+    h->count++;
+    return true;
+}
+
+void* hmapGet(const Hmap* h, const char* key)
+{
+    HmapEntry** slot = findSlot(h, key);
+    return *slot ? (*slot)->value : nullptr;
+}
+
+bool hmapHas(const Hmap* h, const char* key)
+{
+    return *findSlot(h, key) != nullptr;
+}
+
+bool hmapRemove(Hmap* h, const char* key)
+{
+    HmapEntry** slot = findSlot(h, key);
+    if (!*slot)
+        return false;
+
+    HmapEntry* entry = *slot;
+    *slot = entry->next;
+    kfree(entry->key);
+    kfree(entry);
+    h->count--;
+    return true;
+}
+
+usize hmapCount(const Hmap* h)
+{
+    return h->count;
+}
+
+void hmapForEach(const Hmap* h, bool (*visit)(const char* key, void* value, void* userData), void* userData)
+{
+    for (usize i = 0; i < h->bucketCount; i++) {
+        for (HmapEntry* entry = h->buckets[i]; entry; entry = entry->next) {
+            if (!visit(entry->key, entry->value, userData))
+                return;
+        }
+    }
+}