Added benchmark scripts

bench/bench_encode.lua

@@ -0,0 +1,60 @@
+local bench = require "util.bench"
+
+
+local libs = {
+  "../json.lua",    -- https://github.com/rxi/json.lua
+  "dkjson.lua",     -- https://github.com/LuaDist/dkjson
+  "jfjson.lua",     -- http://regex.info/blog/lua/json
+  "json4lua.lua",   -- https://github.com/craigmj/json4lua
+}
+
+
+-- Build table which will be encoded: wikipedia example stored 1000 times
+local data = {}
+for i = 1, 1000 do
+  table.insert(data, {
+    firstName = "John",
+    lastName = "Smith",
+    isAlive = true,
+    age = 25,
+    address = {
+      streetAddress = "21 2nd Street",
+      city = "New York",
+      state = "NY",
+      postalCode = "10021-3100"
+    },
+    phoneNumbers = {
+      { type = "home", number = "212 555-1234" },
+      { type = "office", number = "646 555-4567" }
+    },
+    children = {},
+    spouse = nil
+  })
+end
+
+
+-- Run benchmarks
+local results = {}
+
+for i, name in ipairs(libs) do
+  local f = loadfile(name)
+  if not f then 
+    error( "failed to load '" .. name ..  "'; run './get_json_libs.sh'" )
+  end
+  local json = f()
+
+  -- Handle special cases
+  if name == "jfjson.lua" then
+    local _encode, _decode = json.encode, json.decode
+    json.encode = function(...) return _encode(json, ...) end
+    json.decode = function(...) return _decode(json, ...) end
+  end
+
+  -- Run and push results
+  local res = bench.run(name, 10, function() json.encode(data) end)
+  table.insert(results, res)
+end
+
+
+bench.print_system_info()
+bench.print_results(results)