http Transfer-Encodeing parser Swift sample

chunked.swift

//: Playground - noun: a place where people can play

import UIKit

var str = "Hello, playground"
let a = "25\r\nThis is the data in the first chunk\r\n" + "1C\r\nand this is the second one\r\n" + "3\r\ncon" + "8\r\nsequence" + "0\r\n\r\n"
let d = a.data(using: .utf8, allowLossyConversion: false)

struct chunked{
    var len:Int = 0
    var leftLen:Int = 0
    var data:Data?
    init(l:Int, rLen:Int){
        len = l
        leftLen -= rLen
    }
}

let b = "\r\n".data(using: .utf8, allowLossyConversion: false)!
var packets :[chunked] = []

func dataToInt(d:Data) ->UInt32{
    
    
    var result:UInt32 = 0
    let x = "0x" + String.init(data: d, encoding: .utf8)!
    
    print("xx:" + x)
    _ = Scanner(string:x).scanHexInt32(&result)
    return result
}
func parser(data:NSData){
    print(data)
    var used = 0
    let total = data.length
    let opt = NSData.SearchOptions.init(rawValue: 0)
    while used < total {
       
        let r = data.range(of: b as Data, options: opt, in: NSRange(location: used,length: data.length-used))
        if r.location != NSNotFound {
            print("used xx: \(used) \(r.location)")
            let l = data.subdata(with: NSMakeRange(used, r.location - used))
            print("l \(l) len: \(l.count)")
            used += l.count // count length
            used += r.length //算上\r\n
            print("used: \(used)")
            let c_leng = Int(dataToInt(d: l))
            if c_leng == 0 {
                let r2 = data.range(of: b as Data, options: opt, in: NSRange(location: used,length: data.length-used))
                if r.location != NSNotFound {
                    used += r2.length
                }
                if used == total{
                    print("find last ")
                    return
                }
                
            }
            print("thunk len: \(c_leng) \(used + c_leng)")
            if used + c_leng <= total {
                var p = chunked.init(l: c_leng, rLen: 0)
                if used + c_leng != total {
                    p.data = data.subdata(with: NSMakeRange(used, c_leng))
                }
                
                packets.append(p)
                used += c_leng
                print("found \(used) \(r.location) \(r.location) \(used) \(p.data)")
            }else {
                print("not full")
                print("found \(used + c_leng ) \(r.location) \(r.location) \(used) ")
                return
            }
            print("used: \(used)")
        }else {
            print("not found")
        }
        print("used: \(used)")
    }
    
}
parser(data: d!)
for p in packets {
    print("len \(p.len) left:\(p.leftLen)")
    if let data = p.data {
        print(data)
    }
}