From cc56e2cece682f95a9bf5f091583b58087514178 Mon Sep 17 00:00:00 2001
From: Pietro Gagliardi <pietro10@mac.com>
Date: Mon, 4 May 2015 20:07:34 -0400
Subject: [PATCH] Implemented clearing realloc() on the OS X backend.

---
 darwin/alloc.m         | 36 ++++++++++++++++++++++++++----------
 darwin/init.m          |  2 ++
 darwin/uipriv_darwin.h |  3 +++
 3 files changed, 31 insertions(+), 10 deletions(-)

diff --git a/darwin/alloc.m b/darwin/alloc.m
index 736bfe9e..25e9ba21 100644
--- a/darwin/alloc.m
+++ b/darwin/alloc.m
@@ -1,38 +1,54 @@
 // 4 december 2014
-#import <stdio.h>
+#import <stdlib.h>
 #import "uipriv_darwin.h"
 
+void initAlloc(void)
+{
+}
+
+#define UINT8(p) ((uint8_t *) (p))
+#define PVOID(p) ((void *) (p))
+#define DATA(p) PVOID(UINT8(p) + sizeof (size_t))
+#define BASE(p) PVOID(UINT8(p) - sizeof (size_t))
+#define SIZE(p) ((size_t *) (p))
+
 void *uiAlloc(size_t size)
 {
 	void *out;
 
-	out = malloc(size);
+	out = malloc(sizeof (size_t) + size);
 	if (out == NULL) {
 		fprintf(stderr, "memory exhausted in uiAlloc()\n");
 		abort();
 	}
-	memset(out, 0, size);
-	return out;
+	memset(DATA(out), 0, size);
+	*SIZE(out) = size;
+	return DATA(out);
 }
 
-void *uiRealloc(void *p, size_t size)
+void *uiRealloc(void *p, size_t new)
 {
 	void *out;
+	size_t *s;
 
 	if (p == NULL)
-		return uiAlloc(size);
-	out = realloc(p, size);
+		return uiAlloc(new);
+	p = BASE(p);
+	out = realloc(p, sizeof (size_t) + new);
 	if (out == NULL) {
 		fprintf(stderr, "memory exhausted in uiRealloc()\n");
 		abort();
 	}
-	// TODO zero the extra memory
-	return out;
+	s = SIZE(out);
+	if (new <= *s)
+		memset(((uint8_t *) DATA(out)) + *s, 0, new - *s);
+	*s = new;
+	return DATA(out);
 }
 
 void uiFree(void *p)
 {
 	if (p == NULL)
 		return;
-	free(p);
+	free(BASE(p));
 }
diff --git a/darwin/init.m b/darwin/init.m
index b620f1a5..738c8c6e 100644
--- a/darwin/init.m
+++ b/darwin/init.m
@@ -53,6 +53,8 @@ const char *uiInit(uiInitOptions *o)
 	[NSApp setActivationPolicy:NSApplicationActivationPolicyRegular];
 	[NSApp setDelegate:[appDelegate new]];
 
+	initAlloc();
+
 	// always do this so we always have an application menu
 	appDelegate().menuManager = [menuManager new];
 	[NSApp setMainMenu:[appDelegate().menuManager makeMenubar]];
diff --git a/darwin/uipriv_darwin.h b/darwin/uipriv_darwin.h
index 2d8fb897..bd486ca8 100644
--- a/darwin/uipriv_darwin.h
+++ b/darwin/uipriv_darwin.h
@@ -46,3 +46,6 @@ extern void finishNewTextField(NSTextField *, BOOL);
 
 // window.m
 extern uiWindow *windowFromNSWindow(NSWindow *);
+
+// alloc.m
+extern void initAlloc(void);