Implemented a proper libk

libk/memory/malloc.c

@@ -0,0 +1,114 @@
+#include <memory/virtual.h>
+#include <memory/physical.h>
+#include <memory/malloc.h>
+#include <stdbool.h>
+#include <stdint.h>
+
+mallocNode_t* mallocListHead = NULL;
+uint32_t mallocVirtualAddr = 0;
+uint32_t mallocPhysicalAddr = 0;
+uint32_t mallocPages = 0;
+
+void mallocInit(uint32_t size) {
+    mallocPages = size / PAGE_SIZE;
+    if (size % PAGE_SIZE > 0) { mallocPages++; }
+
+    mallocPhysicalAddr = (uint32_t)allocBlocks(mallocPages);
+    mallocListHead = (mallocNode_t*)mallocVirtualAddr;
+    
+    // Map pages
+    for (uint32_t i = 0, virtualAddr = mallocVirtualAddr; i < mallocPages; i++, virtualAddr += PAGE_SIZE) {
+        mapPage((void*)(mallocPhysicalAddr + i * PAGE_SIZE), (void*)virtualAddr);
+
+        ptEntry_t* page = getPage(virtualAddr);
+        SET_ATTR(page, PTE_READ_WRITE);
+    }
+
+    if (mallocListHead) {
+        mallocListHead->size = (mallocPages * PAGE_SIZE) - sizeof(mallocNode_t);
+        mallocListHead->free = true;
+        mallocListHead->next = NULL;
+    }
+}
+
+void mallocSplit(mallocNode_t* node, uint32_t size) {
+    if (node->size < size + sizeof(mallocNode_t)) { return; } // Can't split - node too small
+    
+    // Remainder node
+    mallocNode_t* newNode = (mallocNode_t*)((void*)node + size + sizeof(mallocNode_t));
+    newNode->size = node->size - size - sizeof(mallocNode_t);
+    newNode->free = true;
+    newNode->next = node->next;
+
+    // Split node
+    node->size = size;
+    node->free = false;
+    node->next = newNode;
+}
+
+void* mallocNextNode(uint32_t size) {
+    if (size == 0) { return NULL; } // Why would you try that? (undefined behaviour i guess)
+    
+    mallocNode_t* current = mallocListHead;
+
+    if (mallocListHead->size == 0) { mallocInit(size); }
+    
+    while (((current->size < size) || !current->free) && current->next != NULL) {
+        current = current->next;
+    }
+
+    if (current->size == size) {
+        current->free = false;
+    } else if (current->size > size + sizeof(mallocNode_t)) {
+        mallocSplit(current, size); // Modifies current into the right size and makes it point to the remainder
+    } else { // There's no large enough node -> try to allocate more pages
+        uint8_t pageCount = 1;
+        while (current->size + pageCount * PAGE_SIZE < size + sizeof(mallocNode_t)) { 
+            pageCount++;
+        }
+
+        // Allocate and map new pages
+        uint32_t virtualAddr = mallocVirtualAddr + mallocPages * PAGE_SIZE;
+        for (uint32_t i = 0; i < pageCount; i++) {
+            ptEntry_t page = 0;
+            uint32_t* temp = allocPage(&page);
+
+            mapPage((void*)temp, (void*)virtualAddr);
+            SET_ATTR(&page, PTE_READ_WRITE);
+            virtualAddr += PAGE_SIZE;
+            current->size += PAGE_SIZE;
+            mallocPages++;
+        }
+
+        mallocSplit(current, size);
+    }
+
+    return (void*)current + sizeof(mallocNode_t);
+}
+
+void mallocMergeFree() {
+    mallocNode_t* current = mallocListHead;
+
+    while (current && current->next != NULL) {
+        if (current->free && current->next->free) {
+            current->size += (current->next->size) + sizeof(mallocNode_t);
+            current->next = current->next->next;
+        }
+        current = current->next;
+    }
+}
+
+void mallocFree(void* ptr) {
+    mallocNode_t* current = mallocListHead;
+
+    while (current->next) {
+        if ((void*)current + sizeof(mallocNode_t) == ptr) {
+            current->free = true;
+            mallocMergeFree();
+            break;
+        }
+
+        current = current->next;
+    }
+}
+