1 files changed, 48 insertions, 0 deletions
diff --git a/usr/klibc/realloc.c b/usr/klibc/realloc.c
new file mode 100644
index 0000000..14a2f2f
--- /dev/null
+++ b/usr/klibc/realloc.c
@@ -0,0 +1,48 @@
+/*
+ * realloc.c
+ */
+
+#include <stdlib.h>
+#include <string.h>
+
+#include "malloc.h"
+
+/* FIXME: This is cheesy, it should be fixed later */
+
+void *realloc(void *ptr, size_t size)
+{
+	struct free_arena_header *ah;
+	void *newptr;
+	size_t oldsize;
+
+	if (!ptr)
+		return malloc(size);
+
+	if (size == 0) {
+		free(ptr);
+		return NULL;
+	}
+
+	/* Add the obligatory arena header, and round up */
+	size = (size + 2 * sizeof(struct arena_header) - 1) & ARENA_SIZE_MASK;
+
+	ah = (struct free_arena_header *)
+	    ((struct arena_header *)ptr - 1);
+
+	if (ah->a.size >= size && size >= (ah->a.size >> 2)) {
+		/* This field is a good size already. */
+		return ptr;
+	} else {
+		/* Make me a new block.  This is kind of bogus; we should
+		   be checking the following block to see if we can do an
+		   in-place adjustment... fix that later. */
+
+		oldsize = ah->a.size - sizeof(struct arena_header);
+
+		newptr = malloc(size);
+		memcpy(newptr, ptr, (size < oldsize) ? size : oldsize);
+		free(ptr);
+
+		return newptr;
+	}
+}