From 713ffbc089f84bdf672caae79d516c271d906944 Mon Sep 17 00:00:00 2001
From: antifallobst <antifallobst@systemausfall.org>
Date: Mon, 29 May 2023 16:23:03 +0200
Subject: [PATCH] feature (hashmaps): implemented hashmaps (NOT TESTED YET)

---
 inc/utils/hashmap.h | 28 +++++++++++++++
 src/utils/hashmap.c | 84 +++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 112 insertions(+)
 create mode 100644 inc/utils/hashmap.h
 create mode 100644 src/utils/hashmap.c

diff --git a/inc/utils/hashmap.h b/inc/utils/hashmap.h
new file mode 100644
index 0000000..23540ad
--- /dev/null
+++ b/inc/utils/hashmap.h
@@ -0,0 +1,28 @@
+// This file is part of noxos and licensed under the MIT open source license
+
+#ifndef NOXOS_HASHMAP_H
+#define NOXOS_HASHMAP_H
+
+#include <utils/stdtypes.h>
+
+typedef struct hashmap_entry_T hashmap_entry_T;
+struct hashmap_entry_T {
+    bool              in_use;
+    uint64_t          key;
+    void*             value;
+    hashmap_entry_T*  prev;
+    hashmap_entry_T*  next;
+};
+
+typedef struct {
+    uint64_t         size;
+    hashmap_entry_T* entries;
+} hashmap_T;
+
+hashmap_T hashmap_create    (uint64_t size);
+void      hashmap_destruct  (hashmap_T* hashmap);
+void      hashmap_insert    (hashmap_T* hashmap, uint64_t key, void* value);
+void      hashmap_delete    (hashmap_T* hashmap, uint64_t key);
+void*     hashmap_lookup    (hashmap_T* hashmap, uint64_t key);
+
+#endif //NOXOS_HASHMAP_H
diff --git a/src/utils/hashmap.c b/src/utils/hashmap.c
new file mode 100644
index 0000000..3ff85e4
--- /dev/null
+++ b/src/utils/hashmap.c
@@ -0,0 +1,84 @@
+// This file is part of noxos and licensed under the MIT open source license
+
+#include <utils/hashmap.h>
+#include <utils/memory.h>
+
+hashmap_T hashmap_create(uint64_t size) {
+    hashmap_T hashmap;
+
+    hashmap.size    = size;
+    hashmap.entries = memory_allocate(size * sizeof(hashmap_entry_T));
+    memory_set(hashmap.entries, 0, size * sizeof(hashmap_entry_T));
+
+    return hashmap;
+}
+
+void hashmap_destruct (hashmap_T* hashmap) {
+    for (uint64_t i = 0; i < hashmap->size; i++) {
+        hashmap_entry_T* entry = hashmap->entries[i].next;
+
+        while (entry != NULL) {
+            hashmap_entry_T* next = entry->next;
+            memory_free(entry);
+            entry = next;
+        }
+    }
+    memory_free(hashmap->entries);
+}
+
+void hashmap_insert(hashmap_T* hashmap, uint64_t key, void* value) {
+    uint64_t index = key % hashmap->size;
+
+    if (!hashmap->entries[index].in_use) {
+        hashmap->entries[index].key    = key;
+        hashmap->entries[index].value  = value;
+        hashmap->entries[index].in_use = true;
+        return;
+    }
+
+    hashmap_entry_T* entry = &hashmap->entries[index];
+    while (entry->next != NULL) entry = entry->next;
+
+    entry->next         = memory_allocate(sizeof(hashmap_entry_T));
+    entry->next->prev   = entry;
+    entry->next->key    = key;
+    entry->next->value  = value;
+    entry->next->in_use = true;
+}
+
+void hashmap_delete(hashmap_T* hashmap, uint64_t key) {
+    uint64_t index = key % hashmap->size;
+
+    hashmap_entry_T* entry = &hashmap->entries[index];
+    while (entry->key != key) {
+        if (entry->next == NULL) return;
+        entry = entry->next;
+    }
+
+    if (entry->prev != NULL) {
+        entry->prev->next = entry->next;
+
+        if (entry->next != NULL) entry->next->prev = entry->prev;
+
+        memory_free(entry);
+        return;
+    }
+
+    entry->key    = 0;
+    entry->value  = NULL;
+    entry->in_use = false;
+}
+
+void* hashmap_lookup(hashmap_T* hashmap, uint64_t key) {
+    uint64_t index = key % hashmap->size;
+
+    hashmap_entry_T* entry = &hashmap->entries[index];
+    while (entry->key != key) {
+        if (entry->next == NULL) return NULL;
+        entry = entry->next;
+    }
+
+    if (!entry->in_use) return NULL;
+
+    return entry->value;
+}
\ No newline at end of file