sooop · June 23, 2024 22:49 · sooop · Jan 23, 2017 · eienf · Jan 7, 2018
diff --git a/StreamReader.swift b/StreamReader.swift
 import Foundation

 class StreamReader {
    let encoding: String.Encoding
    let chunkSize: Int
    let fileHandle: FileHandle
    var buffer: Data
    let delimPattern : Data
    var isAtEOF: Bool = false
    
    init?(url: URL, delimeter: String = "\n", encoding: String.Encoding = .utf8, chunkSize: Int = 4096)
    {
        guard let fileHandle = try? FileHandle(forReadingFrom: url) else { return nil }
        self.fileHandle = fileHandle
        self.chunkSize = chunkSize
        self.encoding = encoding
        buffer = Data(capacity: chunkSize)
        delimPattern = delimeter.data(using: .utf8)!
    }
    
    deinit {
        fileHandle.closeFile()
    }
    
    func rewind() {
        fileHandle.seek(toFileOffset: 0)
        buffer.removeAll(keepingCapacity: true)
        isAtEOF = false
    }
    
    func nextLine() -> String? {
        if isAtEOF { return nil }
        
        repeat {
            if let range = buffer.range(of: delimPattern, options: [], in: buffer.startIndex..<buffer.endIndex) {
                let subData = buffer.subdata(in: buffer.startIndex..<range.lowerBound)
                let line = String(data: subData, encoding: encoding)
                buffer.replaceSubrange(buffer.startIndex..<range.upperBound, with: [])
                return line
            } else {
                let tempData = fileHandle.readData(ofLength: chunkSize)
                if tempData.count == 0 {
                    isAtEOF = true
                    return (buffer.count > 0) ? String(data: buffer, encoding: encoding) : nil
                }
                buffer.append(tempData)
            }
        } while true
    }
 }
	import Foundation

	class StreamReader {
	let encoding: String.Encoding
	let chunkSize: Int
	let fileHandle: FileHandle
	var buffer: Data
	let delimPattern : Data
	var isAtEOF: Bool = false

	init?(url: URL, delimeter: String = "\n", encoding: String.Encoding = .utf8, chunkSize: Int = 4096)
	{
	guard let fileHandle = try? FileHandle(forReadingFrom: url) else { return nil }
	self.fileHandle = fileHandle
	self.chunkSize = chunkSize
	self.encoding = encoding
	buffer = Data(capacity: chunkSize)
	delimPattern = delimeter.data(using: .utf8)!
	}

	deinit {
	fileHandle.closeFile()
	}

	func rewind() {
	fileHandle.seek(toFileOffset: 0)
	buffer.removeAll(keepingCapacity: true)
	isAtEOF = false
	}

	func nextLine() -> String? {
	if isAtEOF { return nil }

	repeat {
	if let range = buffer.range(of: delimPattern, options: [], in: buffer.startIndex..<buffer.endIndex) {
	let subData = buffer.subdata(in: buffer.startIndex..<range.lowerBound)
	let line = String(data: subData, encoding: encoding)
	buffer.replaceSubrange(buffer.startIndex..<range.upperBound, with: [])
	return line
	} else {
	let tempData = fileHandle.readData(ofLength: chunkSize)
	if tempData.count == 0 {
	isAtEOF = true
	return (buffer.count > 0) ? String(data: buffer, encoding: encoding) : nil
	}
	buffer.append(tempData)
	}
	} while true
	}
	}