cmark

diff --git a/src/blocks.c b/src/blocks.c
@@ -19,15 +19,15 @@ static node_block* make_block(int tag, int start_line, int start_column)
 {
 	node_block* e;
 
-	e = malloc(sizeof(node_block));
-	memset(e, 0x0, sizeof(*e));
-
-	e->tag = tag;
-	e->open = true;
-	e->start_line = start_line;
-	e->start_column = start_column;
-	e->end_line = start_line;
-	strbuf_init(&e->string_content, 32);
+	e = calloc(1, sizeof(*e));
+    if(e != NULL) {
+    	e->tag = tag;
+	    e->open = true;
+    	e->start_line = start_line;
+	    e->start_column = start_column;
+    	e->end_line = start_line;
+	    strbuf_init(&e->string_content, 32);
+    }
 
 	return e;
 }
@@ -310,14 +310,17 @@ static int parse_list_marker(chunk *input, int pos, struct ListData ** dataptr)
 		if (!isspace(peek_at(input, pos))) {
 			return 0;
 		}
-		data = malloc(sizeof(struct ListData));
-		data->marker_offset = 0; // will be adjusted later
-		data->list_type = bullet;
-		data->bullet_char = c;
-		data->start = 1;
-		data->delimiter = period;
-		data->tight = false;
-
+		data = calloc(1, sizeof(*data));
+        if(data == NULL) {
+            return 0;
+        } else {
+    		data->marker_offset = 0; // will be adjusted later
+	    	data->list_type = bullet;
+		    data->bullet_char = c;
+    		data->start = 1;
+	    	data->delimiter = period;
+		    data->tight = false;
+        }
 	} else if (isdigit(c)) {
 		int start = 0;
 
@@ -332,13 +335,17 @@ static int parse_list_marker(chunk *input, int pos, struct ListData ** dataptr)
 			if (!isspace(peek_at(input, pos))) {
 				return 0;
 			}
-			data = malloc(sizeof(struct ListData));
-			data->marker_offset = 0; // will be adjusted later
-			data->list_type = ordered;
-			data->bullet_char = 0;
-			data->start = start;
-			data->delimiter = (c == '.' ? period : parens);
-			data->tight = false;
+			data = calloc(1, sizeof(*data));
+            if(data == NULL) {
+                return 0;
+            } else {
+    			data->marker_offset = 0; // will be adjusted later
+	    		data->list_type = ordered;
+		    	data->bullet_char = 0;
+			    data->start = start;
+    			data->delimiter = (c == '.' ? period : parens);
+	    		data->tight = false;
+            }
 		} else {
 			return 0;
 		}

diff --git a/src/chunk.h b/src/chunk.h
@@ -59,10 +59,11 @@ static inline unsigned char *chunk_to_cstr(chunk *c)
 {
 	unsigned char *str;
 
-	str = malloc(c->len + 1);
-	memcpy(str, c->data, c->len);
-	str[c->len] = 0;
-
+	str = calloc(c->len + 1, sizeof(*str));
+    if(str != NULL) {
+    	memcpy(str, c->data, c->len);
+	    str[c->len] = 0;
+    }
 	return str;
 }
 

diff --git a/src/inlines.c b/src/inlines.c
@@ -39,8 +39,10 @@ static unsigned char *bufdup(const unsigned char *buf)
 
 	if (buf) {
 		int len = strlen((char *)buf);
-		new = malloc(len + 1);
-		memcpy(new, buf, len + 1);
+		new = calloc(len + 1, sizeof(*new));
+        if(new != NULL) {
+    		memcpy(new, buf, len + 1);
+        }
 	}
 
 	return new;
@@ -48,12 +50,14 @@ static unsigned char *bufdup(const unsigned char *buf)
 
 static inline node_inl *make_link_(node_inl *label, unsigned char *url, unsigned char *title)
 {
-	node_inl* e = (node_inl*) malloc(sizeof(node_inl));
-	e->tag = INL_LINK;
-	e->content.linkable.label = label;
-	e->content.linkable.url   = url;
-	e->content.linkable.title = title;
-	e->next = NULL;
+	node_inl* e = calloc(1, sizeof(*e));
+    if(e != NULL) {
+    	e->tag = INL_LINK;
+    	e->content.linkable.label = label;
+	    e->content.linkable.url   = url;
+    	e->content.linkable.title = title;
+	    e->next = NULL;
+    }
 	return e;
 }
 
@@ -75,29 +79,35 @@ inline static node_inl* make_link(node_inl* label, chunk url, chunk title)
 
 inline static node_inl* make_inlines(int t, node_inl* contents)
 {
-	node_inl* e = (node_inl*) malloc(sizeof(node_inl));
-	e->tag = t;
-	e->content.inlines = contents;
-	e->next = NULL;
+	node_inl * e = calloc(1, sizeof(*e));
+    if(e != NULL) {
+    	e->tag = t;
+	    e->content.inlines = contents;
+    	e->next = NULL;
+    }
 	return e;
 }
 
 // Create an inline with a literal string value.
 inline static node_inl* make_literal(int t, chunk s)
 {
-	node_inl* e = (node_inl*) malloc(sizeof(node_inl));
-	e->tag = t;
-	e->content.literal = s;
-	e->next = NULL;
+	node_inl * e = calloc(1, sizeof(*e));
+    if(e != NULL) {
+    	e->tag = t;
+	    e->content.literal = s;
+    	e->next = NULL;
+    }
 	return e;
 }
 
 // Create an inline with no value.
 inline static node_inl* make_simple(int t)
 {
-	node_inl* e = (node_inl*) malloc(sizeof(node_inl));
-	e->tag = t;
-	e->next = NULL;
+	node_inl* e = calloc(1, sizeof(*e));
+    if(e != NULL) {
+    	e->tag = t;
+	    e->next = NULL;
+    }
 	return e;
 }
 
@@ -382,6 +392,9 @@ cannotClose:
 	if (can_open)
 	{
 		istack = (inline_stack*)malloc(sizeof(inline_stack));
+                if (istack == NULL) {
+                  return NULL;
+                }
 		istack->delim_count = numdelims;
 		istack->delim_char = c;
 		istack->first_inline = inl_text;

diff --git a/src/references.c b/src/references.c
@@ -16,10 +16,12 @@ refhash(const unsigned char *link_ref)
 
 static void reference_free(reference *ref)
 {
-	free(ref->label);
-	free(ref->url);
-	free(ref->title);
-	free(ref);
+    if(ref != NULL) {
+	    free(ref->label);
+    	free(ref->url);
+	    free(ref->title);
+    	free(ref);
+    }
 }
 
 // normalize reference:  collapse internal whitespace to single space,
@@ -31,6 +33,9 @@ static unsigned char *normalize_reference(chunk *ref)
 	strbuf normalized = GH_BUF_INIT;
 	unsigned char *result;
 
+    if(ref == NULL)
+        return NULL;
+
 	if (ref->len == 0)
 		return NULL;
 
@@ -75,14 +80,16 @@ extern void reference_create(reference_map *map, chunk *label, chunk *url, chunk
 	if (reflabel == NULL)
 		return;
 
-	ref = malloc(sizeof(reference));
-	ref->label = reflabel;
-	ref->hash = refhash(ref->label);
-	ref->url = clean_url(url);
-	ref->title = clean_title(title);
-	ref->next = NULL;
+	ref = calloc(1, sizeof(*ref));
+    if(ref != NULL) {
+        ref->label = reflabel;
+        ref->hash = refhash(ref->label);
+        ref->url = clean_url(url);
+        ref->title = clean_title(title);
+        ref->next = NULL;
 
-	add_reference(map, ref);
+        add_reference(map, ref);
+    }
 }
 
 // Returns reference if refmap contains a reference with matching
@@ -118,6 +125,9 @@ void reference_map_free(reference_map *map)
 {
 	unsigned int i;
 
+    if(map == NULL)
+        return;
+
 	for (i = 0; i < REFMAP_SIZE; ++i) {
 		reference *ref = map->table[i];
 		reference *next;
@@ -134,7 +144,5 @@ void reference_map_free(reference_map *map)
 
 reference_map *reference_map_new(void)
 {
-	reference_map *map = malloc(sizeof(reference_map));
-	memset(map, 0x0, sizeof(reference_map));
-	return map;
+    return calloc(1, sizeof(reference_map));
 }