added faster transformation to snake case

CHANGELOG.md

@@ -1,4 +1,7 @@
 ## CHANGELOG
 
+v0.10.0:
+-  added high performance custom transformation to snake case (underscore), which is more than 2 times faster than the original
+
 v0.9.0:
 -  underscore replaces now hyphens (https://github.com/ruby2elixir/atomic_map/pull/5 + https://github.com/ruby2elixir/atomic_map/pull/6)

README.md

@@ -27,6 +27,10 @@ iex> AtomicMap.convert(%{ "CamelCase" => [ %{"c" => 1}, %{"c" => 2}] }, safe: fa
 iex> AtomicMap.convert(%{ "CamelCase" => [ %{"c" => 1}, %{"c" => 2}] }, safe: false, underscore: false )
 %{CamelCase: [%{c: 1}, %{c: 2}]}
 
+# in case you have extra large maps and you wish to use the faster custom transformation to underscore, you can pass `high_perf: true`
+AtomicMap.convert(%{ "CamelCase" => [ %{"c" => 1}, %{"c" => 2}] }, safe: false, high_perf: true)
+%{camel_case: [%{c: 1}, %{c: 2}]}
+
 # hyphens are replaced
 iex> AtomicMap.convert(%{ "some-key" => [ %{"c" => 1}, %{"c" => 2}] }, safe: false, underscore: true )
 %{some_key: [%{c: 1}, %{c: 2}]}
@@ -41,7 +45,7 @@ AtomicMap.convert(%{ "CamelCase" => [ %{"c" => 1}, %{"c" => 2}] }, safe: true, i
   1. Add atomic_map to your list of dependencies in `mix.exs`:
 
         def deps do
-          [{:atomic_map, "~> 0.8"}]
+          [{:atomic_map, "~> 0.10"}]
         end
 
 ## Todo:

bench/basic_bench.exs

@@ -18,6 +18,12 @@ defmodule BasicBench do
   @long_string "StringShouldChange-some_stuffStringShouldChange-some_stuffStringShouldChange-some_stuffStringShouldChange-some_stuffStringShouldChange-some_stuff"
   @short_string "StringShouldChange-some_stuff"
 
+  @payload_camel_cased File.read!("bench/test-payload-camel-cased.json") |> Poison.decode!()
+  @large_payload_camel_cased 1..100 |> Enum.reduce(%{}, fn(x, acc) -> Map.put(acc, "key#{x}", @payload_camel_cased) end)
+
+  @payload_snake_cased File.read!("bench/test-payload-camel-cased.json") |> Poison.decode!()
+  @large_payload_snake_cased 1..100 |> Enum.reduce(%{}, fn(x, acc) -> Map.put(acc, "key#{x}", @payload_snake_cased) end)
+
   bench "macro_underscore - long" do
     @long_string |> macro_underscore
   end
@@ -33,4 +39,20 @@ defmodule BasicBench do
   bench "regex_underscore - short" do
     @short_string |> regex_underscore
   end
+
+  bench "large dict camel cased with low perf underscore" do
+    @large_payload_camel_cased |> AtomicMap.convert(safe: false, underscore: true, high_perf: false)
+  end
+
+  bench "large dict camel cased with high perf underscore" do
+    @large_payload_camel_cased |> AtomicMap.convert(safe: false, underscore: true, high_perf: true)
+  end
+
+  bench "large dict snake cased with low perf underscore" do
+    @large_payload_snake_cased |> AtomicMap.convert(safe: false, underscore: true, high_perf: false)
+  end
+
+  bench "large dict snake cased with high perf underscore" do
+    @large_payload_snake_cased |> AtomicMap.convert(safe: false, underscore: true, high_perf: true)
+  end
 end

bench/snapshots/2017-11-21_11-13-42.snapshot

@@ -0,0 +1,10 @@
+duration:1.0;mem stats:false;sys mem stats:false
+module;test;tags;iterations;elapsed
+BasicBench	large dict camel cased with high perf underscore		10	1256231
+BasicBench	large dict camel cased with low perf underscore		5	1467331
+BasicBench	large dict snake cased with high perf underscore		10	1223200
+BasicBench	large dict snake cased with low perf underscore		5	1507264
+BasicBench	macro_underscore - long		50000	2172177
+BasicBench	macro_underscore - short		100000	1185552
+BasicBench	regex_underscore - long		50000	2968897
+BasicBench	regex_underscore - short		100000	1680492