diff --git a/json_object.c b/json_object.c
index f2b5ce0..669602f 100644
--- a/json_object.c
+++ b/json_object.c
@@ -87,7 +87,7 @@ static void json_object_fini(void) {
 
 /* string escaping */
 
-static int json_escape_str(struct printbuf *pb, char *str, int len)
+static int json_escape_str(struct printbuf *pb, char *str, size_t len)
 {
   int pos = 0, start_offset = 0;
   unsigned char c;
@@ -290,7 +290,7 @@ static void indent(struct printbuf *pb, int level, int flags)
 
 /* json_object_object */
 
-static int json_object_object_to_json_string(struct json_object* jso,
+static long long json_object_object_to_json_string(struct json_object* jso,
 					     struct printbuf *pb,
 					     int level,
 						 int flags)
@@ -429,7 +429,7 @@ void json_object_object_del(struct json_object* jso, const char *key)
 
 /* json_object_boolean */
 
-static int json_object_boolean_to_json_string(struct json_object* jso,
+static long long json_object_boolean_to_json_string(struct json_object* jso,
 					      struct printbuf *pb,
 					      int level,
 						  int flags)
@@ -467,7 +467,7 @@ json_bool json_object_get_boolean(struct json_object *jso)
 
 /* json_object_int */
 
-static int json_object_int_to_json_string(struct json_object* jso,
+static long long json_object_int_to_json_string(struct json_object* jso,
 					  struct printbuf *pb,
 					  int level,
 					  int flags)
@@ -554,13 +554,13 @@ int64_t json_object_get_int64(struct json_object *jso)
 
 /* json_object_double */
 
-static int json_object_double_to_json_string(struct json_object* jso,
+static long long json_object_double_to_json_string(struct json_object* jso,
 					     struct printbuf *pb,
 					     int level,
 						 int flags)
 {
   char buf[128], *p, *q;
-  int size;
+  long long size;
 
   size = snprintf(buf, 128, "%f", jso->o.c_double);
   p = strchr(buf, ',');
@@ -614,7 +614,7 @@ double json_object_get_double(struct json_object *jso)
 
 /* json_object_string */
 
-static int json_object_string_to_json_string(struct json_object* jso,
+static long long json_object_string_to_json_string(struct json_object* jso,
 					     struct printbuf *pb,
 					     int level,
 						 int flags)
@@ -642,7 +642,7 @@ struct json_object* json_object_new_string(const char *s)
   return jso;
 }
 
-struct json_object* json_object_new_string_len(const char *s, int len)
+struct json_object* json_object_new_string_len(const char *s, size_t len)
 {
   struct json_object *jso = json_object_new(json_type_string);
   if(!jso) return NULL;
@@ -666,7 +666,7 @@ const char* json_object_get_string(struct json_object *jso)
   }
 }
 
-int json_object_get_string_len(struct json_object *jso)  {
+size_t json_object_get_string_len(struct json_object *jso)  {
   if(!jso) return 0;
   switch(jso->o_type) {
   case json_type_string:
@@ -679,7 +679,7 @@ int json_object_get_string_len(struct json_object *jso)  {
 
 /* json_object_array */
 
-static int json_object_array_to_json_string(struct json_object* jso,
+static long long json_object_array_to_json_string(struct json_object* jso,
                                             struct printbuf *pb,
                                             int level,
                                             int flags)
diff --git a/json_object.h b/json_object.h
index 6270309..1f8e1de 100644
--- a/json_object.h
+++ b/json_object.h
@@ -82,7 +82,7 @@ typedef void (json_object_delete_fn)(struct json_object *jso, void *userdata);
 /**
  * Type of a custom serialization function.  See json_object_set_serializer.
  */
-typedef int (json_object_to_json_string_fn)(struct json_object *jso,
+typedef long long (json_object_to_json_string_fn)(struct json_object *jso,
 						struct printbuf *pb,
 						int level,
 						int flags);
@@ -530,7 +530,7 @@ extern double json_object_get_double(struct json_object *obj);
  */
 extern struct json_object* json_object_new_string(const char *s);
 
-extern struct json_object* json_object_new_string_len(const char *s, int len);
+extern struct json_object* json_object_new_string_len(const char *s, size_t len);
 
 /** Get the string value of a json_object
  *
@@ -553,7 +553,7 @@ extern const char* json_object_get_string(struct json_object *obj);
  * @param obj the json_object instance
  * @returns int
  */
-extern int json_object_get_string_len(struct json_object *obj);
+extern size_t json_object_get_string_len(struct json_object *obj);
 
 #ifdef __cplusplus
 }
diff --git a/json_object_private.h b/json_object_private.h
index 5ed791b..deff7e8 100644
--- a/json_object_private.h
+++ b/json_object_private.h
@@ -33,7 +33,7 @@ struct json_object
     struct array_list *c_array;
     struct {
         char *str;
-        int len;
+        size_t len;
     } c_string;
   } o;
   json_object_delete_fn *_user_delete;
diff --git a/json_util.c b/json_util.c
index 111fa01..5c9be66 100644
--- a/json_util.c
+++ b/json_util.c
@@ -70,7 +70,8 @@ struct json_object* json_object_from_file(const char *filename)
   struct printbuf *pb;
   struct json_object *obj;
   char buf[JSON_FILE_BUF_SIZE];
-  int fd, ret;
+  int fd;
+  ssize_t ret;
 
   if((fd = open(filename, O_RDONLY)) < 0) {
     MC_ERROR("json_object_from_file: error reading file %s: %s\n",
@@ -102,7 +103,8 @@ struct json_object* json_object_from_file(const char *filename)
 int json_object_to_file_ext(char *filename, struct json_object *obj, int flags)
 {
   const char *json_str;
-  int fd, ret;
+  int fd;
+  ssize_t ret;
   unsigned int wpos, wsize;
 
   if(!obj) {
@@ -215,7 +217,7 @@ int json_parse_int64(const char *buf, int64_t *retval)
 		char buf_cmp[100];
 		char *buf_cmp_start = buf_cmp;
 		int recheck_has_neg = 0;
-		int buf_cmp_len;
+		size_t buf_cmp_len;
 
 		// Skip leading zeros, but keep at least one digit
 		while (buf_sig_digits[0] == '0' && buf_sig_digits[1] != '\0')
@@ -240,7 +242,7 @@ int json_parse_int64(const char *buf, int64_t *retval)
 		 */
 		if (orig_has_neg != recheck_has_neg ||
 		    strncmp(buf_sig_digits, buf_cmp_start, strlen(buf_cmp_start)) != 0 ||
-			((int)strlen(buf_sig_digits) != buf_cmp_len &&
+			(strlen(buf_sig_digits) != buf_cmp_len &&
 			 isdigit((int)buf_sig_digits[buf_cmp_len])
 		    )
 		   )
diff --git a/printbuf.c b/printbuf.c
index 9d56522..97b4d0f 100644
--- a/printbuf.c
+++ b/printbuf.c
@@ -29,7 +29,7 @@
 #include "debug.h"
 #include "printbuf.h"
 
-static int printbuf_extend(struct printbuf *p, int min_size);
+static int printbuf_extend(struct printbuf *p, size_t min_size);
 
 struct printbuf* printbuf_new(void)
 {
@@ -55,10 +55,10 @@ struct printbuf* printbuf_new(void)
  * Note: this does not check the available space!  The caller
  *  is responsible for performing those calculations.
  */
-static int printbuf_extend(struct printbuf *p, int min_size)
+static int printbuf_extend(struct printbuf *p, size_t min_size)
 {
 	char *t;
-	int new_size;
+	size_t new_size;
 
 	if (p->size >= min_size)
 		return 0;
@@ -76,7 +76,7 @@ static int printbuf_extend(struct printbuf *p, int min_size)
 	return 0;
 }
 
-int printbuf_memappend(struct printbuf *p, const char *buf, int size)
+size_t printbuf_memappend(struct printbuf *p, const char *buf, size_t size)
 {
   if (p->size <= p->bpos + size + 1) {
     if (printbuf_extend(p, p->bpos + size + 1) < 0)
@@ -88,9 +88,9 @@ int printbuf_memappend(struct printbuf *p, const char *buf, int size)
   return size;
 }
 
-int printbuf_memset(struct printbuf *pb, int offset, int charvalue, int len)
+int printbuf_memset(struct printbuf *pb, size_t offset, int charvalue, int len)
 {
-	int size_needed;
+	size_t size_needed;
 
 	if (offset == -1)
 		offset = pb->bpos;
diff --git a/printbuf.h b/printbuf.h
index b1bde7f..beecc36 100644
--- a/printbuf.h
+++ b/printbuf.h
@@ -22,8 +22,8 @@ extern "C" {
 
 struct printbuf {
   char *buf;
-  int bpos;
-  int size;
+  size_t bpos;
+  size_t size;
 };
 
 extern struct printbuf*
@@ -36,12 +36,12 @@ printbuf_new(void);
  * Your code should not use printbuf_memappend directly--use
  * printbuf_memappend_fast instead.
  */
-extern int
-printbuf_memappend(struct printbuf *p, const char *buf, int size);
+extern size_t
+printbuf_memappend(struct printbuf *p, const char *buf, size_t size);
 
 #define printbuf_memappend_fast(p, bufptr, bufsize)          \
 do {                                                         \
-  if ((p->size - p->bpos) > bufsize) {                       \
+  if ((p->size - p->bpos) > (size_t)(bufsize)) {             \
     memcpy(p->buf + p->bpos, (bufptr), bufsize);             \
     p->bpos += bufsize;                                      \
     p->buf[p->bpos]= '\0';                                   \
@@ -59,7 +59,7 @@ do {                                                         \
  * If offset is -1, this starts at the end of the current data in the buffer.
  */
 extern int
-printbuf_memset(struct printbuf *pb, int offset, int charvalue, int len);
+printbuf_memset(struct printbuf *pb, size_t offset, int charvalue, int len);
 
 extern int
 sprintbuf(struct printbuf *p, const char *msg, ...);