Improve the init_allocator function

allocator.c

@@ -8,12 +8,6 @@
 #define FOOTER_MAGIC_01 2783946
 #define FOOTER_MAGIC_02 878512284
 
-struct allocator {
-  u8 *buf;
-  u64 size;
-  u64 used;
-};
-
 struct block_boundary {
   u64 size;
   bool free;
@@ -24,34 +18,74 @@ struct block_boundary {
 typedef struct block_boundary block_header;
 typedef struct block_boundary block_footer;
 
-typedef struct {
-  block_header header;
-  u8 *data;
-  block_footer footer;
-} block_t;
+struct allocator {
+  u8 *buf;
+  u64 size;
+  u64 used;
+  u64 block_count;
+  u64 free_max_size;
+  u64 free_count;
+  block_header **free_blocks; // Array of pointers
+};
 
 allocator_t *init_allocator(u64 size) {
   allocator_t *allocator = (allocator_t *)malloc(sizeof(allocator_t));
 
   if (!allocator) {
+    deinit_allocator(&allocator);
     return NULL;
   }
 
   allocator->buf = (u8 *)malloc(size);
 
   if (!(allocator->buf)) {
-    free(allocator);
+    deinit_allocator(&allocator);
     return NULL;
   }
 
   allocator->size = size;
   allocator->used = 0;
+  allocator->block_count = allocator->free_count = 1;
+
+  // Each memory block has a header and footer, so the maximum number of blocks
+  // that can be added to the buffer can be calculated by assuming blocks of
+  // size 0 (i.e. only containing a header and a footer)
+  allocator->free_max_size =
+      size / (sizeof(block_header) + sizeof(block_footer));
+
+  allocator->free_blocks = (block_header **)malloc(allocator->free_max_size);
+
+  if (!(allocator->free_blocks)) {
+    deinit_allocator(&allocator);
+    return NULL;
+  }
+
+  block_header *header = (block_header *)allocator->buf;
+  block_footer *footer =
+      (block_footer *)(allocator->buf + size - sizeof(block_footer));
+
+  header->size = size;
+  footer->size = size - sizeof(block_footer);
+  header->free = footer->free = true;
+
+  header->magic_01 = HEADER_MAGIC_01;
+  header->magic_02 = HEADER_MAGIC_02;
+
+  footer->magic_01 = FOOTER_MAGIC_01;
+  footer->magic_02 = FOOTER_MAGIC_02;
+
+  allocator->free_blocks[0] = header;
 
   return allocator;
 }
 
 void deinit_allocator(allocator_t **allocator) {
   if (*allocator != NULL) {
+    if ((*allocator)->free_blocks != NULL) {
+      free((*allocator)->free_blocks);
+      (*allocator)->free_blocks = NULL;
+    }
+
     if ((*allocator)->buf != NULL) {
       free((*allocator)->buf);
       (*allocator)->buf = NULL;
@@ -62,4 +96,7 @@ void deinit_allocator(allocator_t **allocator) {
   }
 }
 
-void *alloc(allocator_t *allocator, u64 size) {}
+// void *alloc(allocator_t *allocator, u64 size) {
+//   ++size;
+//   return NULL;
+// }