introduce json_object_new_string_ext

json_object.c

@@ -1020,69 +1020,51 @@ static void json_object_string_delete(struct json_object* jso)
 	json_object_generic_delete(jso);
 }
 
-struct json_object* json_object_new_string_noalloc(char *s)
+struct json_object* json_object_new_string_ext(const char *s, const size_t len, int flags)
 {
 	struct json_object *jso = json_object_new(json_type_string);
+	(void) flags;
 	if (!jso)
 		return NULL;
 	jso->_delete = &json_object_string_delete;
 	jso->_to_json_string = &json_object_string_to_json_string;
-	jso->o.c_string.len = strlen(s);
-	if(jso->o.c_string.len < LEN_DIRECT_STRING_DATA) {
-		memcpy(jso->o.c_string.str.data, s, jso->o.c_string.len);
-		free(s);
-	} else {
-		jso->o.c_string.str.ptr = s;
-	}
-	return jso;
-}
-
-struct json_object* json_object_new_string(const char *s)
-{
-	struct json_object *jso = json_object_new(json_type_string);
-	if (!jso)
-		return NULL;
-	jso->_delete = &json_object_string_delete;
-	jso->_to_json_string = &json_object_string_to_json_string;
-	jso->o.c_string.len = strlen(s);
-	if(jso->o.c_string.len < LEN_DIRECT_STRING_DATA) {
-		memcpy(jso->o.c_string.str.data, s, jso->o.c_string.len);
+	if(len < LEN_DIRECT_STRING_DATA) {
+		memcpy(jso->o.c_string.str.data, s, len);
+	} else if (flags & JSON_C_NEW_STRING_NO_STRDUP) {
+		/* a little hack to cast away constness */
+		jso->o.c_string.str.ptr = *((char **)((void *)(&s)));
 	} else {
-		jso->o.c_string.str.ptr = strdup(s);
-		if (!jso->o.c_string.str.ptr)
+		char *dstbuf = (flags & JSON_C_NEW_STRING_STRDUP) ?
+				strdup(s) : (char *) malloc(len + 1);
+		if(!dstbuf)
 		{
 			json_object_generic_delete(jso);
 			errno = ENOMEM;
 			return NULL;
 		}
+		if (flags & JSON_C_NEW_STRING_LENGTH) {
+			memcpy(dstbuf, (const void *)s, len);
+			dstbuf[len] = '\0';
+		}
+		jso->o.c_string.str.ptr = dstbuf;
 	}
+	jso->o.c_string.len = len;
 	return jso;
 }
 
+struct json_object* json_object_new_string_noalloc(char *s)
+{
+	return json_object_new_string_ext(s, strlen(s), JSON_C_NEW_STRING_NO_STRDUP);
+}
+
+struct json_object* json_object_new_string(const char *s)
+{
+	return json_object_new_string_ext(s, strlen(s), JSON_C_NEW_STRING_STRDUP);
+}
+
 struct json_object* json_object_new_string_len(const char *s, const int len)
 {
-	char *dstbuf;
-	struct json_object *jso = json_object_new(json_type_string);
-	if (!jso)
-		return NULL;
-	jso->_delete = &json_object_string_delete;
-	jso->_to_json_string = &json_object_string_to_json_string;
-	if(len < LEN_DIRECT_STRING_DATA) {
-		dstbuf = jso->o.c_string.str.data;
-	} else {
-		jso->o.c_string.str.ptr = (char*)malloc(len + 1);
-		if (!jso->o.c_string.str.ptr)
-		{
-			json_object_generic_delete(jso);
-			errno = ENOMEM;
-			return NULL;
-		}
-		dstbuf = jso->o.c_string.str.ptr;
-	}
-	memcpy(dstbuf, (const void *)s, len);
-	dstbuf[len] = '\0';
-	jso->o.c_string.len = len;
-	return jso;
+	return json_object_new_string_ext(s, len, JSON_C_NEW_STRING_LENGTH);
 }
 
 const char* json_object_get_string(struct json_object *jso)

json_object.h

@@ -134,6 +134,21 @@ extern "C" {
  */
 #define JSON_C_OPTION_THREAD (1)
 
+/**
+ * A flag to duplicate given string with strdup while creating new string object
+ */
+#define JSON_C_NEW_STRING_STRDUP (0)
+
+/**
+ * A flag to transfer ownership of given string buffer to newly created string object
+ */
+#define JSON_C_NEW_STRING_NO_STRDUP (1<<0)
+
+/**
+ * A flaag to allocate a buffer of "len" bytes while creating a new string obejct
+ */
+#define JSON_C_NEW_STRING_LENGTH (1<<1)
+
 /**
  * A structure to use with json_object_object_foreachC() loops.
  * Contains key, val and entry members.
@@ -893,6 +908,8 @@ JSON_EXPORT int json_object_set_double(struct json_object *obj,double new_value)
 
 /* string type methods */
 
+JSON_EXPORT struct json_object* json_object_new_string_ext(const char *s, const size_t len, int flags);
+
 /** Create a new empty json_object of type json_type_string
  *
  * Use given string as is, do not call malloc if given string is longer