From b35f7d482a47b0d042366fcf307b7751b3cf28a7 Mon Sep 17 00:00:00 2001
From: Nathan Reiner <nathan@nathanreiner.xyz>
Date: Mon, 6 Feb 2023 13:48:24 +0100
Subject: add realloc

---
 lib/malloc/malloc.c | 45 +++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 43 insertions(+), 2 deletions(-)

(limited to 'lib/malloc/malloc.c')

diff --git a/lib/malloc/malloc.c b/lib/malloc/malloc.c
index a0e9ebf..e941c31 100644
--- a/lib/malloc/malloc.c
+++ b/lib/malloc/malloc.c
@@ -111,6 +111,47 @@ void free(void *ptr)
 }
 
 
+/** DOC
+ * @type function
+ * @name realloc
+ *
+ * @param  void *ptr
+ * @param  u64  size
+ * @return void*
+ *
+ * @description
+ * Copies content of *ptr to a new location and returns new adress.
+ */
+void *realloc(void *ptr, u64 size)
+{
+	segment_t *seg = mbrk.first;
+	void *mem;
+	char *d;
+
+	for (; seg; seg = seg->next) {
+		if (ptr == seg->ptr)
+			break;
+	}
+
+	if (!seg)
+		return 0;
+
+	if (seg->size == size)
+		return seg->ptr;
+
+	mem = malloc(size);
+	d = mem;
+
+	for (const char *p = (const char*)ptr; p < (const char*)ptr + seg->size; ++p) {
+		*(d++) = *p;
+	}
+
+	free(ptr);
+
+	return mem;
+}
+
+
 /** DOC
  * @type function
  * @name __initialize_memory
@@ -143,7 +184,7 @@ segment_t *__find_free_segment(u64 size)
 	segment_t * seg = mbrk.first;
 
 	for (; seg; seg = seg->next) {
-		if (seg->free && size == seg->size)
+		if (seg->free && seg->size == size)
 			return seg;
 	}
 
@@ -171,7 +212,7 @@ segment_t *__allocate_new(u64 size)
 	brk((void*)mbrk.current);
 
 	segment_t *seg = (segment_t*)last;
-	seg->ptr = (void*)(mbrk.current - size);
+	seg->ptr = (void*)(last + sizeof(segment_t));
 	seg->size = size;
 	seg->free = 0;
 	seg->next = 0;
-- 
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