Replace boost::next with std::next (#896)

Summary:
- Replace uses of `boost::next` with `std::next`.
- Replace uses of `boost::prior` with `std::prev`.
Pull Request resolved: https://github.com/facebook/folly/pull/896

Reviewed By: ot

Differential Revision: D9114372

Pulled By: yfeldblum

fbshipit-source-id: 4b15b81ffb43dee00b64c4abc171747a95ceb6b7

folly/json.cpp

@@ -17,10 +17,10 @@
 
 #include <algorithm>
 #include <functional>
+#include <iterator>
 #include <type_traits>
 
 #include <boost/algorithm/string.hpp>
-#include <boost/next_prior.hpp>
 
 #include <folly/Conv.h>
 #include <folly/Portability.h>
@@ -145,7 +145,7 @@ struct Printer {
     indent();
     newline();
     (*this)(a[0]);
-    for (auto& val : range(boost::next(a.begin()), a.end())) {
+    for (auto& val : range(std::next(a.begin()), a.end())) {
       out_ += ',';
       newline();
       (*this)(val);

folly/test/DynamicTest.cpp

@@ -19,7 +19,7 @@
 #include <folly/json.h>
 #include <folly/portability/GTest.h>
 
-#include <boost/next_prior.hpp>
+#include <iterator>
 
 using folly::dynamic;
 
@@ -52,12 +52,12 @@ TEST(Dynamic, ObjectBasics) {
   found.emplace_back(newObject.keys().begin()->asString(),
                      *newObject.values().begin());
 
-  EXPECT_EQ(*boost::next(newObject.keys().begin()),
-            boost::next(newObject.items().begin())->first);
-  EXPECT_EQ(*boost::next(newObject.values().begin()),
-            boost::next(newObject.items().begin())->second);
-  found.emplace_back(boost::next(newObject.keys().begin())->asString(),
-                     *boost::next(newObject.values().begin()));
+  EXPECT_EQ(*std::next(newObject.keys().begin()),
+            std::next(newObject.items().begin())->first);
+  EXPECT_EQ(*std::next(newObject.values().begin()),
+            std::next(newObject.items().begin())->second);
+  found.emplace_back(std::next(newObject.keys().begin())->asString(),
+                     *std::next(newObject.values().begin()));
 
   std::sort(found.begin(), found.end());
 
@@ -178,7 +178,7 @@ TEST(Dynamic, ObjectErase) {
   obj["asd"] = 42.0;
   obj["foo"] = 42.0;
   EXPECT_EQ(obj.size(), 3);
-  auto ret = obj.erase(boost::next(obj.items().begin()), obj.items().end());
+  auto ret = obj.erase(std::next(obj.items().begin()), obj.items().end());
   EXPECT_TRUE(ret == obj.items().end());
   EXPECT_EQ(obj.size(), 1);
   obj.erase(obj.items().begin());
@@ -194,7 +194,7 @@ TEST(Dynamic, ArrayErase) {
   arr.erase(arr.begin());
   EXPECT_EQ(arr.size(), 5);
 
-  arr.erase(boost::next(arr.begin()), boost::prior(arr.end()));
+  arr.erase(std::next(arr.begin()), std::prev(arr.end()));
   EXPECT_EQ(arr.size(), 2);
   EXPECT_EQ(arr[0], 2);
   EXPECT_EQ(arr[1], 6);

folly/test/JsonTest.cpp

@@ -13,11 +13,12 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-#include <limits>
-
-#include <boost/next_prior.hpp>
 
 #include <folly/json.h>
+
+#include <iterator>
+#include <limits>
+
 #include <folly/portability/GTest.h>
 
 using folly::dynamic;
@@ -85,7 +86,7 @@ TEST(Json, Parse) {
     "[12,false, false  , null , [12e4,32, [], 12]]");
   EXPECT_EQ(array.size(), 5);
   if (array.size() == 5) {
-    EXPECT_EQ(boost::prior(array.end())->size(), 4);
+    EXPECT_EQ(std::prev(array.end())->size(), 4);
   }
 
   EXPECT_THROW(parseJson("\n[12,\n\nnotvalidjson"),