Added benchmark scripts

bench/bench_decode.lua

@@ -0,0 +1,63 @@
+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
+}
+
+
+-- JSON string: wikipedia example stored 1000 times in an array
+local text = "[" .. string.rep([[{
+  "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": null
+}, ]], 1000):sub(1, -3) .. "]"
+
+
+-- Run benchmarks, store results
+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.decode(text) end)
+  table.insert(results, res)
+end
+
+
+bench.print_system_info()
+bench.print_results(results)