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vurvdevvurvdev
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Benchmarks, overhauls
* true and false decode as their respective lua values now. * null decodes as a special table instance stored as the field 'NULL' on the qjson library. * largely rewrote entire library to make decoder faster. * added benchmarks * removed false information about this being thousands of times faster than rxi/json * deleted qjson_simple, not worth maintaining. Could make a smaller one not focused on performance at all if I wanted to.
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‎README.md‎

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<img src="qjson.svg" height=150px />
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<img src="qjson.svg" height=150px/>
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Tiny, quick JSON encoding/decoding in pure Lua.
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# [![Release Shield](https://img.shields.io/github/v/release/Vurv78/qjson.lua?include_prereleases)](https://github.com/Vurv78/qjson.lua/releases/latest) [![License](https://img.shields.io/github/license/Vurv78/qjson.lua?color=red)](https://opensource.org/licenses/MIT) [![Linter Badge](https://github.com/Vurv78/qjson.lua/workflows/Run%20Lest/badge.svg)](https://github.com/Vurv78/qjson.lua/actions) [![github/Vurv78](https://img.shields.io/discord/824727565948157963?label=Discord&logo=discord&logoColor=ffffff&labelColor=7289DA&color=2c2f33)](https://discord.gg/yXKMt2XUXm)
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(Running `decode` benchmark by [`rxi/json.lua`](https://github.com/rxi/json.lua), encode benchmarks soon (currently ~3x faster))
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```
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Lua version : LuaJIT 2.1.0-beta3
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CPU name : 11th Gen Intel(R) Core(TM) i7-11800H @ 2.30GHz
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../json.lua : 0.00494s [x7.06e+03] (min: 0.00452s, max 0.00526s)
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dkjson.lua : 0.0121s [x1.73e+04] (min: 0.0118s, max 0.0123s)
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jfjson.lua : 0.00993s [x1.42e+04] (min: 0.00954s, max 0.0103s)
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qjson_simple.lua : 4.3e-06s [x6.14] (min: 0s, max 1.6e-05s)
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qjson.lua : 7e-07s [x1] (min: 0s, max 1e-06s)
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```
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## Features
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* Pure lua, should work on every version (5.1-5.4, JIT)
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* Incredibly fast: ~10000x faster than rxi/json at decoding.
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* Actually tiny, < 150 loc.
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* Quick, focused on performance. (See benchmarks below)
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* Actually tiny, ~150 sloc.
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* Decent error handling: `Expected : to follow key for object at char 39`
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## Usage
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})
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--[[
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{"qjson": ["fast","simple","tiny"],"hello": "world!"}
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{"qjson":["fast","simple","tiny"],"hello":"world!"}
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]]
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print(json.decode([[
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```
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## Notes
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* `true`, `false` and `null` are represented as strings.
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* `null` is output as a special table instance, retrieved from `qjson.NULL`
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* This does not guarantee 100% compatibility with the more niche parts of the JSON spec (like unicode escapes)
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## Benchmarks
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Using benchmarks/bench.lua:
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```
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LuaJIT 2.1.0-beta3
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11th Gen Intel(R) Core(TM) i7-11800H @ 2.30GHz
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## qjson_simple
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Running benchmarks...
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| Name (Decode) | Min | Max | Avg | Avg / Best |
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| vurv78/qjson | 0.0091 | 0.012012 | 0.00968749 | x1.75539 |
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| rxi/json | 0.004745 | 0.006889 | 0.0055187 | x1 |
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| actboy168/json | 0.010586 | 0.012723 | 0.0113411 | x2.05503 |
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| luadist/dkjson | 0.011112 | 0.016785 | 0.0134858 | x2.44366 |
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Smaller initial version of `qjson` without all of the optimizations that make it less readable.
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| Name (Encode) | Min | Max | Avg | Avg / Best |
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| vurv78/qjson | 0.003788 | 0.004491 | 0.004021 | x1 |
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| rxi/json | 0.0104 | 0.014977 | 0.0108013 | x2.68623 |
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| actboy168/json | 0.010361 | 0.012899 | 0.0110817 | x2.75596 |
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| luadist/dkjson | 0.014438 | 0.017056 | 0.0153153 | x3.80883 |
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```
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```
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Lua 5.3
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11th Gen Intel(R) Core(TM) i7-11800H @ 2.30GHz
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Running benchmarks...
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| Name (Decode) | Min | Max | Avg | Avg / Best |
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| vurv78/qjson | 0.015195 | 0.018472 | 0.0159068 | x1 |
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| rxi/json | 0.045206 | 0.052624 | 0.048079 | x3.02255 |
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| actboy168/json | 0.019059 | 0.022751 | 0.0200545 | x1.26075 |
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| luadist/dkjson | 0.028623 | 0.034445 | 0.0307014 | x1.93009 |
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| Name (Encode) | Min | Max | Avg | Avg / Best |
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| vurv78/qjson | 0.006012 | 0.017234 | 0.00760202 | x1 |
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| rxi/json | 0.015458 | 0.019752 | 0.0170518 | x2.24306 |
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| actboy168/json | 0.015981 | 0.021264 | 0.0169299 | x2.22703 |
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| luadist/dkjson | 0.02172 | 0.025274 | 0.0229826 | x3.02323 |
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```
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Often runs worse than `qjson`, but can run at around the same speed.
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From here, you can see this library is significantly faster on regular lua, and a bit slower than rxi/json on LuaJIT.
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Doesn't support escaping strings, exponential numbers, or `null`.
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Currently working on making it faster for LuaJIT, but this is pretty hard to fix considering making it faster would require not using as many [lua patterns](https://www.lua.org/pil/20.2.html), which would slow down PUC-Lua.

‎benchmarks/bench.lua‎

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---@alias BenchResult { min: number, max: number, avg: number }
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local function bench(times, fn) ---@return BenchResult
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collectgarbage() -- Clear gc before running
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for _ = 1, 5 do -- Warm up
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fn()
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end
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local results --[=[@type number[]]=] = {}
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for i = 1, times do
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local start = os.clock()
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fn()
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results[i] = os.clock() - start
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end
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local min, max, avg = math.huge, -math.huge, 0
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for _, time in ipairs(results) do
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if time < min then
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min = time
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elseif time > max then
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max = time
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end
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avg = avg + time
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end
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return {
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min = min, max = max, avg = avg / times
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}
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end
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local function get(url)
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local handle = assert(io.popen("curl -s " .. url))
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local content = handle:read("*a")
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handle:close()
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return content
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end
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local loadstring = loadstring or load
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print("Downloading required files...")
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local LIBS --[[@type table<string, table>]] = {
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["vurv78/qjson"] = require "qjson",
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["rxi/json"] = loadstring(get("https://raw.githubusercontent.com/rxi/json.lua/master/json.lua"))(),
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["actboy168/json"] = loadstring(get("https://raw.githubusercontent.com/actboy168/json.lua/master/json.lua"))(),
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["luadist/dkjson"] = loadstring(get("https://raw.githubusercontent.com/LuaDist/dkjson/master/dkjson.lua"))(),
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}
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local DECODE_TARGET = get("https://raw.githubusercontent.com/simdjson/simdjson/master/jsonexamples/twitter.json")
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local ENCODE_TARGET = require("qjson").decode(DECODE_TARGET)
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local util = require "benchmarks.util"
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print( util.version )
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print( util.cpu )
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print("Running benchmarks... ")
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do
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local total --[=[@type table<string, BenchResult>]=] = {}
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for name, lib in pairs(LIBS) do
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local decode = lib.decode
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total[name] = bench(100, function()
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decode(DECODE_TARGET)
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end)
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end
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local best = math.huge
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for _, result in pairs(total) do
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if result.avg < best then
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best = result.avg
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end
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end
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print( ("| %-15s | %-10s | %-10s | %-10s | %-11s |"):format("Name (Decode)", "Min", "Max", "Avg", "Avg / Best") )
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for name, result in pairs(total) do
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print( ("| %-15s | %-10g | %-10g | %-10g | x%-10g |"):format(name, result.min, result.max, result.avg, result.avg / best) )
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end
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end
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print()
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do
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local total --[=[@type table<string, BenchResult>]=] = {}
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for name, lib in pairs(LIBS) do
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local encode = lib.encode
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total[name] = bench(100, function()
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encode(ENCODE_TARGET)
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end)
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end
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local best = math.huge
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for _, result in pairs(total) do
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if result.avg < best then
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best = result.avg
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end
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end
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print( ("| %-15s | %-10s | %-10s | %-10s | %-11s |"):format("Name (Encode)", "Min", "Max", "Avg", "Avg / Best") )
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for name, result in pairs(total) do
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print( ("| %-15s | %-10g | %-10g | %-10g | x%-10g |"):format(name, result.min, result.max, result.avg, result.avg / best) )
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end
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end

‎benchmarks/util.lua‎

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local os = package.config:sub(1, 1) == "\\" and "Windows" or "Unix"
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local cpu
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if os == "Windows" then
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local handle, err = io.popen("wmic cpu get name /VALUE")
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assert(handle, err)
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cpu = handle:read("*a"):match("Name=([^\n]+)")
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handle:close()
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else
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local handle, err = io.popen([[lscpu | sed -nr '/Model name/ s/.*:\s*(.* @ .*)/\1/p']])
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assert(handle, err)
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cpu = handle:read("*a")
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handle:close()
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end
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return {
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os = os,
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version = jit and jit.version or _VERSION,
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cpu = cpu
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}

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