File I/O

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FileIO1.swift

#!/usr/bin/env swift;
/******************************************************************************
 * This program simply copies a file to the console character by
 * character like the Unix 'cat' program.
 * 
 * Copyright © 2020 Richard Lesh.  All rights reserved.
 *****************************************************************************/

import Foundation
import Utils

func readTextFile(_ filespec:String) throws -> Void {
	var ifh:StreamReader? = StreamReader(filespec)
	if ifh == nil {
		throw RuntimeError("Problem opening input file!")
	}
	var c:Int?
	c = ifh!.getCodepoint()
	while c != nil {
		print(Utils.chr(c!), terminator: "")
		c = ifh!.getCodepoint()
	}
	ifh!.close()
}

func main() -> Void {
	if CommandLine.arguments.count != 2 {
		print("Syntax: " + CommandLine.arguments[0] + " {filename}")
		exit(1)
	}
	let FILESPEC:String = CommandLine.arguments[1]
	do {
		try readTextFile(FILESPEC)
	} catch let ex as RuntimeError {
		print("Error: " + ex.localizedDescription)
	} catch {
		print("Unexpected File Read Error")
	}
	exit(EXIT_SUCCESS)
}
main()

FileIO2.swift

#!/usr/bin/env swift;
/******************************************************************************
 * This program simply copies a file to the console line by line.
 * 
 * Copyright © 2020 Richard Lesh.  All rights reserved.
 *****************************************************************************/

import Foundation
import Utils

func readTextFile(_ filespec:String) throws -> Void {
	let IFH:StreamReader? = StreamReader(filespec)
	if IFH == nil {
		throw RuntimeError("Problem opening input file!")
	}
	var line:String?
	line = IFH!.getLine()
	while line != nil {
		print(line!)
		line = IFH!.getLine()
	}
	IFH!.close()
}

func main() -> Void {
	if CommandLine.arguments.count != 2 {
		print("Syntax: " + CommandLine.arguments[0] + " {filename}")
		exit(1)
	}
	let FILESPEC:String = CommandLine.arguments[1]
	do {
		try readTextFile(FILESPEC)
	} catch let ex as RuntimeError {
		print("Error: " + ex.localizedDescription)
	} catch {
		print("Unexpected File Read Error")
	}
	exit(EXIT_SUCCESS)
}
main()

FileIO3.swift

#!/usr/bin/env swift;
/******************************************************************************
 * This program reads bytes from a file and prints them in hexadecimal format.
 * 
 * Copyright © 2021 Richard Lesh.  All rights reserved.
 *****************************************************************************/

import Foundation
import Utils

func readBinaryFile(_ filespec:String) throws -> Void {
	let IFH:FileHandle? = FileHandle(forReadingAtPath: filespec)
	if IFH == nil {
		throw RuntimeError("Problem opening input file!")
	}
	var c:UInt8?
	var count:Int = 0
	c = Utils.getbyte(IFH!)
	while c != nil {
		print(Utils.format("{0:02x} ", c!), terminator: "")
		count += 1
		if count % 16 == 0 {
			print()
		}
		c = Utils.getbyte(IFH!)
	}
	if count % 16 != 0 {
		print()
	}
	try IFH!.close()
}

func main() -> Void {
	if CommandLine.arguments.count != 2 {
		print("Syntax: " + CommandLine.arguments[0] + " {filename}")
		exit(1)
	}
	let FILESPEC:String = CommandLine.arguments[1]
	do {
		try readBinaryFile(FILESPEC)
	} catch let ex as RuntimeError {
		print("Error: " + ex.localizedDescription)
	} catch {
		print("Unexpected File Read Error")
	}
	exit(EXIT_SUCCESS)
}
main()

FileIO4.swift

#!/usr/bin/env swift;
/******************************************************************************
 * This program simply writes characters from the alphabet to a file.
 * 
 * Copyright © 2020 Richard Lesh.  All rights reserved.
 *****************************************************************************/

import Foundation
import Utils

func writeTextFile(_ filespec:String) throws -> Void {
	FileManager.default.createFile(atPath: filespec, contents: nil)
	let OFH:FileHandle? = FileHandle(forWritingAtPath: filespec)
	if OFH == nil {
		throw RuntimeError("Problem opening output file!")
	}
// Latin alphabet
	for c:Int in 0x41...0x5A {
		OFH!.write(Utils.chr(c).data(using: .utf8)!)
	}
	OFH!.write("\n".data(using: .utf8)!)
// Greek alphabet
	for c:Int in 0x391...0x3A9 {
		OFH!.write(Utils.chr(c).data(using: .utf8)!)
	}
	OFH!.write("\n".data(using: .utf8)!)
// Cyrillic alphabet
	for c:Int in 0x410...0x42F {
		OFH!.write(Utils.chr(c).data(using: .utf8)!)
	}
	OFH!.write("\n".data(using: .utf8)!)
// Katakana alphabet
	for c:Int in 0x30A0...0x30FF {
		OFH!.write(Utils.chr(c).data(using: .utf8)!)
	}
	OFH!.write("\n".data(using: .utf8)!)
	OFH!.synchronizeFile()
	OFH!.closeFile()
}

func main() -> Void {
	if CommandLine.arguments.count != 2 {
		print("Syntax: " + CommandLine.arguments[0] + " {filename}")
		exit(1)
	}
	let FILESPEC:String = CommandLine.arguments[1]
	do {
		try writeTextFile(FILESPEC)
	} catch let ex as RuntimeError {
		print("Error: " + ex.localizedDescription)
	} catch {
		print("Unexpected File Read Error")
	}
	exit(EXIT_SUCCESS)
}
main()

FileIO5.swift

#!/usr/bin/env swift;
/******************************************************************************
 * This program simply writes lines with the alphabet to a file.
 * 
 * Copyright © 2020 Richard Lesh.  All rights reserved.
 *****************************************************************************/

import Foundation
import Utils

func writeTextFile(_ filespec:String) throws -> Void {
	FileManager.default.createFile(atPath: filespec, contents: nil)
	let OFH:FileHandle? = FileHandle(forWritingAtPath: filespec)
	if OFH == nil {
		throw RuntimeError("Problem opening output file!")
	}
	OFH!.write("ABCDEFGHIJKLMNOPQRSTUVWXYZ".data(using: .utf8)!);OFH!.write("\n".data(using: .utf8)!)
	OFH!.write("ΑΒΓΔΕΖΗΘΙΚΛΜΝΞΟΠΡΣΤΥΦΧΨΩ".data(using: .utf8)!);OFH!.write("\n".data(using: .utf8)!)
	OFH!.write("АБВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯ".data(using: .utf8)!);OFH!.write("\n".data(using: .utf8)!)
	OFH!.write("゠ァアィイゥウェエォオカガキギクグケゲコゴサザシジスズセゼソゾタ".data(using: .utf8)!);OFH!.write("\n".data(using: .utf8)!)
	OFH!.write("ダチヂッツヅテデトドナニヌネノハバパヒビピフブプヘベペホボポマミ".data(using: .utf8)!);OFH!.write("\n".data(using: .utf8)!)
	OFH!.write("ムメモャヤュユョヨラリルレロヮワヰヱヲンヴヵヶヷヸヹヺ・ーヽヾヿ".data(using: .utf8)!);OFH!.write("\n".data(using: .utf8)!)
	OFH!.closeFile()
}

func main() -> Void {
	if CommandLine.arguments.count != 2 {
		print("Syntax: " + CommandLine.arguments[0] + " {filename}")
		exit(1)
	}
	let FILESPEC:String = CommandLine.arguments[1]
	do {
		try writeTextFile(FILESPEC)
	} catch let ex as RuntimeError {
		print("Error: " + ex.localizedDescription)
	} catch {
		print("Unexpected File Write Error")
	}
	exit(EXIT_SUCCESS)
}
main()

FileIO6.swift

#!/usr/bin/env swift;
/******************************************************************************
 * This program simply writes the bytes 0 - 256 to a binary file.
 * 
 * Copyright © 2021 Richard Lesh.  All rights reserved.
 *****************************************************************************/

import Foundation
import Utils

func writeBinaryFile(_ filespec:String) throws -> Void {
	FileManager.default.createFile(atPath: filespec, contents: nil)
	let OFH:FileHandle? = FileHandle(forWritingAtPath: filespec)
	if OFH == nil {
		throw RuntimeError("Problem opening output file!")
	}
	for b:Int in 0...255 {
		OFH!.write(Data([UInt8(b)]))
	}
	try OFH!.close()
}

func main() -> Void {
	if CommandLine.arguments.count != 2 {
		print("Syntax: " + CommandLine.arguments[0] + " {filename}")
		exit(1)
	}
	var filespec:String = CommandLine.arguments[1]
	do {
		try writeBinaryFile(filespec)
	} catch let ex as RuntimeError {
		print("Error: " + ex.localizedDescription)
	}
	exit(EXIT_SUCCESS)
}
main()

FileIO7.swift

#!/usr/bin/env swift;
/******************************************************************************
 * This program simply copies one file to another, character by
 * character like the Unix 'cat' program.
 * 
 * Copyright © 2020 Richard Lesh.  All rights reserved.
 *****************************************************************************/

import Foundation
import Utils

func copyTextFile(_ fromFilespec:String, _ toFilespec:String) throws -> Void {
	let IFH:StreamReader? = StreamReader(fromFilespec)
	FileManager.default.createFile(atPath: toFilespec, contents: nil)
	let OFH:FileHandle? = FileHandle(forWritingAtPath: toFilespec)
	if IFH == nil {
		throw RuntimeError("Problem opening input file!")
	}
	if OFH == nil {
		throw RuntimeError("Problem opening output file!")
	}
	var c:Int?
	c = IFH!.getCodepoint()
	while c != nil {
		OFH!.write(Utils.chr(c!).data(using: .utf8)!)
		c = IFH!.getCodepoint()
	}
	IFH!.close()
	try OFH!.close()
}

func main() -> Void {
	if CommandLine.arguments.count != 3 {
		print("Syntax: " + CommandLine.arguments[0] + " {fromFilespec} {toFilespec}")
		exit(1)
	}
	var fromFilespec:String = CommandLine.arguments[1]
	var toFilespec:String = CommandLine.arguments[2]
	do {
		try copyTextFile(fromFilespec, toFilespec)
	} catch let ex as RuntimeError {
		print("Error: " + ex.localizedDescription)
	}
	exit(EXIT_SUCCESS)
}
main()

FileIO8.swift

#!/usr/bin/env swift;
/******************************************************************************
 * This program simply copies one file to another, line by line.
 * 
 * Copyright © 2020 Richard Lesh.  All rights reserved.
 *****************************************************************************/

import Foundation
import Utils

func copyTextFile(_ fromFilespec:String, _ toFilespec:String) throws -> Void {
	let IFH:StreamReader? = StreamReader(fromFilespec)
	FileManager.default.createFile(atPath: toFilespec, contents: nil)
	let OFH:FileHandle? = FileHandle(forWritingAtPath: toFilespec)
	if IFH == nil {
		throw RuntimeError("Problem opening input file!")
	}
	if OFH == nil {
		throw RuntimeError("Problem opening output file!")
	}
	var line:String?
	line = IFH!.getLine()
	while line != nil {
		OFH!.write(line!.data(using: .utf8)!);OFH!.write("\n".data(using: .utf8)!)
		line = IFH!.getLine()
	}
	IFH!.close()
	try OFH!.close()
}

func main() -> Void {
	if CommandLine.arguments.count != 3 {
		print("Syntax: " + CommandLine.arguments[0] + " {fromFilespec} {toFilespec}")
		exit(1)
	}
	var fromFilespec:String = CommandLine.arguments[1]
	var toFilespec:String = CommandLine.arguments[2]
	do {
		try copyTextFile(fromFilespec, toFilespec)
	} catch let ex as RuntimeError {
		print("Error: " + ex.localizedDescription)
	}
	exit(EXIT_SUCCESS)
}
main()

FileIO9.swift

#!/usr/bin/env swift;
/******************************************************************************
 * This program reads bytes from a binary file and copies them to another file.
 * 
 * Copyright © 2021 Richard Lesh.  All rights reserved.
 *****************************************************************************/

import Foundation
import Utils

func copyBinaryFile(_ fromFilespec:String, _ toFilespec:String) throws -> Void {
	let IFH:FileHandle? = FileHandle(forReadingAtPath: fromFilespec)
	FileManager.default.createFile(atPath: toFilespec, contents: nil)
	let OFH:FileHandle? = FileHandle(forWritingAtPath: toFilespec)
	if IFH == nil {
		throw RuntimeError("Problem opening input file!")
	}
	if OFH == nil {
		throw RuntimeError("Problem opening output file!")
	}
	var c:UInt8?
	c = Utils.getbyte(IFH!)
	while c != nil {
		OFH!.write(Data([UInt8(c!)]))
		c = Utils.getbyte(IFH!)
	}
	try IFH!.close()
	try OFH!.close()
}

func main() -> Void {
	if CommandLine.arguments.count != 3 {
		print("Syntax: " + CommandLine.arguments[0] + " {fromFilespec} {toFilespec}")
		exit(1)
	}
	var fromFilespec:String = CommandLine.arguments[1]
	var toFilespec:String = CommandLine.arguments[2]
	do {
		try copyBinaryFile(fromFilespec, toFilespec)
	} catch let ex as RuntimeError {
		print("Error: " + ex.localizedDescription)
	}
	exit(EXIT_SUCCESS)
}
main()

Questions

• {{Who's on first?}}
• {{Who's on second?}}
• {{Who's on third?}}

Projects

More ★'s indicate higher difficulty level.

• Base64 Decoding
• Base64 Encoding
• ChaCha20 Cipher
• Number of Primes
• One-Way Hash
• Palindrome Search
• Spell Checker
• XOR Cipher

References

• [[Swift Community]]
• [[Swift Language Guide]]
• [[Swift Language Reference]]
• [[Swift Programming Language]], Apple Inc.
• [[Swift Doc]]
• [[We Heart Swift]]
• [[Swift Cookbook]]
• [[Swift Playground]]
• [[Swift at TutorialsPoint]]
• [[Hacking with Swift]]