add realloc

2 files changed, 20 insertions, 0 deletions

diff --git a/stage3/heap.c b/stage3/heap.c
index dd1b23a..0a82213 100644
--- a/stage3/heap.c
+++ b/stage3/heap.c
@@ -1,5 +1,6 @@
 #include "halt.h"
 #include "heap.h"
+#include "memory.h"
 
 #define PAGESIZE 0x1000
 #define MAGIC ((void *) 0x69)
@@ -74,6 +75,24 @@ void *malloc(usize size)
 	return nil;
 }
 
+void *realloc(void *ptr, usize size)
+{
+	if (ptr == nil)
+		return malloc(size);
+
+	Header *h = ((Header *) ptr) - 1;
+
+	if (h->next != MAGIC)
+		panic("realloc: invalid pointer");
+
+	void *new = malloc(size);
+
+	memcpy(new, ptr, h->size);
+	free(ptr);
+
+	return new;
+}
+
 void heap_init()
 {
 	free_ptr = &init_free_ptr;
diff --git a/stage3/heap.h b/stage3/heap.h
index bf02e43..39bd70d 100644
--- a/stage3/heap.h
+++ b/stage3/heap.h
@@ -12,5 +12,6 @@ void heap_add_region(MemRegion *region);
 void *try_malloc(usize size);
 void *malloc(usize siz);
 void free(void *ptr);
+void *realloc(void *ptr, usize size);
 
 #endif