From 6944f48d30a581d437bc2c8f873a499291412bb7 Mon Sep 17 00:00:00 2001
From: Marvin Borner
Date: Sun, 7 Feb 2021 00:51:32 +0100
Subject: Many small memory improvements

---
 libc/inc/mem.h |  3 +++
 libc/mem.c     | 18 +++++++++++++++++-
 2 files changed, 20 insertions(+), 1 deletion(-)

(limited to 'libc')

diff --git a/libc/inc/mem.h b/libc/inc/mem.h
index a01c9a2..e35ee62 100644
--- a/libc/inc/mem.h
+++ b/libc/inc/mem.h
@@ -5,6 +5,8 @@
 
 #include <def.h>
 
+int malloc_allocated;
+
 void *malloc_debug(u32 size, const char *file, int line, const char *func, const char *inp);
 void free_debug(void *ptr, const char *file, int line, const char *func, const char *inp);
 #define malloc(size) malloc_debug(size, __FILE__, __LINE__, __func__, #size)
@@ -26,5 +28,6 @@ void *memcpy(void *dest, const void *src, u32 n);
 void *memset(void *dest, int val, u32 n);
 void *memchr(void *src, int c, u32 n);
 int memcmp(const void *s1, const void *s2, u32 n);
+int mememp(const u8 *buf, u32 n);
 
 #endif
diff --git a/libc/mem.c b/libc/mem.c
index 17703d5..aab68b2 100644
--- a/libc/mem.c
+++ b/libc/mem.c
@@ -69,12 +69,20 @@ int memcmp(const void *s1, const void *s2, u32 n)
 	return 0;
 }
 
+int mememp(const u8 *buf, u32 n)
+{
+	return buf[0] == 0 && !memcmp(buf, buf + 1, n - 1);
+}
+
 /**
  * Heap allocator
  */
 
 #ifdef kernel
 
+int malloc_allocated = 0;
+
+#define HEAP_MAGIC 0x42424242
 #define HEAP_INIT_SIZE 0xff000000
 #define HEAP_MIN_SIZE HEAP_INIT_SIZE
 #define MIN_ALLOC_SZ 4
@@ -85,6 +93,7 @@ int memcmp(const void *s1, const void *s2, u32 n)
 /* #define MAX_WILDERNESS 0x1000000 */
 
 struct h_node {
+	u32 magic;
 	u32 hole;
 	u32 size;
 	struct h_node *next;
@@ -107,6 +116,7 @@ struct heap {
 
 void node_add(struct h_bin *bin, struct h_node *node)
 {
+	node->magic = HEAP_MAGIC;
 	node->next = NULL;
 	node->prev = NULL;
 	if (!bin->head) {
@@ -237,6 +247,7 @@ void heap_init(u32 start)
 
 void *_malloc(u32 size)
 {
+	malloc_allocated += size;
 	u32 index = bin_index(size);
 	struct h_bin *temp = (struct h_bin *)&heap.bins[index];
 	struct h_node *found = node_best_fit(temp, size);
@@ -248,8 +259,11 @@ void *_malloc(u32 size)
 		found = node_best_fit(temp, size);
 	}
 
+	assert(found->magic == HEAP_MAGIC);
+
 	if ((found->size - size) > (OVERHEAD + MIN_ALLOC_SZ)) {
 		struct h_node *split = (struct h_node *)(((char *)found + OVERHEAD) + size);
+		split->magic = HEAP_MAGIC;
 		split->size = found->size - size - OVERHEAD;
 		split->hole = 1;
 
@@ -287,7 +301,9 @@ void _free(void *p)
 	struct h_bin *list;
 	struct h_footer *new_foot, *old_foot;
 
-	struct h_node *head = (struct h_node *)((char *)p - 8);
+	struct h_node *head = (struct h_node *)((char *)p - 12);
+	assert(head->magic == HEAP_MAGIC && head->hole == 0);
+	malloc_allocated -= head->size;
 	if (head == (struct h_node *)(u32 *)heap.start) {
 		head->hole = 1;
 		node_add(&heap.bins[bin_index(head->size)], head);
-- 
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