libc.obj: Add allocator

just add allocator instead of `_ksys_alloc`, `_ksys_free` and `_ksys_realloc`.

programs/develop/ktcc/trunk/libc.obj/source/stdlib/malloc.c

@@ -1,7 +1,128 @@
+#include <string.h>
 #include <stdlib.h>
+#include <errno.h>
 #include <sys/ksys.h>
+#include <stdbool.h>
+#include "_mem.h"
+
+static struct mem_node* __new_mem_node_from_exist(struct mem_node* current_node, size_t size, bool* from_empty_node)
+{
+    struct mem_node* new_node = NULL;
+    // Check if the current node has enough free space for the requested size.
+    if (size + sizeof(struct mem_node) <= current_node->free) {
+
+        *from_empty_node = MEM_NODE_IS_FREE(current_node);
+        if (*from_empty_node) {
+            new_node = current_node;
+        } else {
+            // Calculate the used memory in current node
+            const size_t s = GET_MEM_NODE_USED_MEM(current_node);
+
+            // Create a new memory node after the current node's used space.
+            new_node = (struct mem_node*)(GET_MEM_NODE_PTR(current_node) + s);
+
+            // Update current node's size
+            current_node->size = s;
+
+            // Set the size of the new node.
+            // for new node give all free space in current node
+            new_node->size = current_node->free - sizeof(struct mem_node);
+
+            // Mark current node as used.
+            current_node->free = 0;
+        }
+    }
+    return new_node;
+}
 
 void* malloc(size_t size)
 {
-    return _ksys_alloc(size);
-}
+    char b[32];
+
+    // Handle zero-size allocation.
+    if (size == 0) {
+        return NULL;
+    }
+
+    // Align the size to 8 bytes.
+    size = __mem_default_align(size);
+
+    struct mem_node* current_node = __mem_node;
+    struct mem_node* new_node = NULL; // Pointer to the new node that will be created.
+    bool from_empty_node = false;
+
+    if (__last_biggest_mem_node != NULL)
+        new_node = __new_mem_node_from_exist(__last_biggest_mem_node, size, &from_empty_node); // try find free space in last created node
+
+    // if cant find in __last_biggest_mem_node
+    if (new_node == NULL) {
+        // Iterate through the linked list of memory nodes.
+        while (current_node != NULL) {
+            new_node = __new_mem_node_from_exist(current_node, size, &from_empty_node);
+            if (new_node)
+                break; // Found a suitable node, exit the loop.
+
+            current_node = current_node->next; // Move to the next node in the list.
+        }
+    }
+
+    // If no suitable node was found in the existing list:
+    if (new_node == NULL) {
+        // Calculate the size of the new block, including the mem_block header, mem_node header and alignment.
+        const size_t s = __mem_align(size + sizeof(struct mem_block) + sizeof(struct mem_node), ALLOC_BLOCK_SIZE);
+
+        // Allocate a new block of memory using the ksys_alloc function (presumably a kernel-level allocation function).
+        struct mem_block* block = (struct mem_block*)_ksys_alloc(s);
+
+        // Check if the allocation was successful.
+        if (block == NULL) {
+            __errno = ENOMEM; // Set the error number to indicate memory allocation failure.
+            return NULL;      // Return NULL to indicate allocation failure.
+        }
+
+        block->size = s;
+
+        // Create a new memory node after the mem_block header.
+        new_node = (struct mem_node*)(((char*)block) + sizeof(struct mem_block));
+
+        // Set the size of the new node.
+        new_node->size = s - sizeof(struct mem_block) - sizeof(struct mem_node);
+    }
+
+    // Set the free space in the new node.
+    new_node->free = new_node->size - size;
+
+    if (!from_empty_node) {
+        // Set the last pointer of the new node to the current node.
+        new_node->last = current_node;
+
+        // Link the new node into the linked list.
+        if (current_node != NULL) {
+            // Set the next pointer of the current node to the new node.
+            new_node->next = current_node->next;
+
+            // Update the last pointer of the next node, if it exists.
+            if (current_node->next != NULL) {
+                current_node->next->last = new_node;
+            }
+            current_node->next = new_node;
+        } else {
+            // If the current node is NULL, the new node is the first node in the list.
+            new_node->next = NULL;
+        }
+    }
+
+    // If the linked list was empty, set the head to the new node.
+    if (__mem_node == NULL) {
+        __mem_node = new_node;
+    }
+
+    if (__last_biggest_mem_node == NULL || new_node->free > __last_biggest_mem_node->free) {
+        __last_biggest_mem_node = new_node;
+    }
+
+    // Return a pointer to the user data area of the new node.
+    return GET_MEM_NODE_PTR(new_node);
+}
+
+#undef __mem_align