Add LICENSE.txt; some minor cleanups

- Add LICENSE.txt
- Add a comment about how we handle numbers
- Add more test code
- Fix a narrowing-conversion issue
- Fix a comment typo

LICENSE.txt

@@ -0,0 +1,19 @@
+Copyright (c) 2013 Dropbox, Inc.
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.

json11.cpp

@@ -300,7 +300,7 @@ static inline string esc(char c) {
     return string(buf);
 }
 
-static inline bool in_range (int x, int lower, int upper) {
+static inline bool in_range(long x, long lower, long upper) {
     return (x >= lower && x <= upper);
 }
 

json11.hpp

@@ -12,6 +12,19 @@
  *
  * Internally, the various types of Json object are represented by the JsonValue class
  * hierarchy.
+ *
+ * A note on numbers - JSON specifies the syntax of number formatting but not its semantics,
+ * so some JSON implementations distinguish between integers and floating-point numbers, while
+ * some don't. In json11, we choose the latter. Because some JSON implementations (namely
+ * Javascript itself) treat all numbers as the same type, distinguishing the two leads
+ * to JSON that will be *silently* changed by a round-trip through those implementations.
+ * Dangerous! To avoid that risk, json11 stores all numbers as double internally, but also
+ * provides integer helpers.
+ *
+ * Fortunately, double-precision IEEE754 ('double') can precisely store any integer in the
+ * range +/-2^53, which includes every 'int' on most systems. (Timestamps often use int64
+ * or long long to avoid the Y2038K problem; a double storing microseconds since some epoch
+ * will be exact for +/- 275 years.)
  */
 
 /* Copyright (c) 2013 Dropbox, Inc.
@@ -118,7 +131,7 @@ class Json final {
     // Return the enclosed std::map if this is an object, or an empty map otherwise.
     const object &object_items() const;
 
-    // Return a reference to arr[i] if this is an object, Json() otherwise.
+    // Return a reference to arr[i] if this is an array, Json() otherwise.
     const Json & operator[](size_t i) const;
     // Return a reference to obj[key] if this is an object, Json() otherwise.
     const Json & operator[](const std::string &key) const;

test.cpp

@@ -4,6 +4,9 @@
 #include <sstream>
 #include "json11.hpp"
 #include <cassert>
+#include <list>
+#include <set>
+#include <unordered_map>
 
 using namespace json11;
 using std::string;
@@ -51,6 +54,16 @@ int main(int argc, char **argv) {
         std::cout << "    - " << k.dump() << "\n";
     }
 
+    std::list<int> l1 { 1, 2, 3 };
+    std::vector<int> l2 { 1, 2, 3 };
+    std::set<int> l3 { 1, 2, 3 };
+    assert(Json(l1) == Json(l2));
+    assert(Json(l2) == Json(l3));
+
+    std::map<string, string> m1 { { "k1", "v1" }, { "k2", "v2" } };
+    std::unordered_map<string, string> m2 { { "k1", "v1" }, { "k2", "v2" } };
+    assert(Json(m1) == Json(m2));
+
     // Json literals
     Json obj = Json::object({
         { "k1", "v1" },