move again

Lab04/content/part1/encrypt/go.mod

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+module encrypt
+
+go 1.18

Lab04/content/part1/encrypt/input.txt

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+New Zealand's capital, Wellington, has been ranked one of the least affordable
+cities in the world for buying a property. The picture is also grim for renters,
+with a 12% rise in prices in the past year. That, along with increases in petrol
+and food prices, has led many to consider moving to nearby Australia -
+where they have the right to live and work.
+Chris, a builder, his partner Harmony and their four daughters recently left
+Wellington to start a new life in the Australian city of Brisbane.
+Despite owning their home and earning reasonable salaries, they were still struggling.
+"We have four kids, so it was expensive. We'd notice Australians saying you know the
+cost of living is going up - but that was the cost five years ago in New Zealand,"
+says Chris. Leaving New Zealand and the rest of her family was a
+difficult decision for Harmony. But she says the move was necessary for the children.
+"You can't make a living in New Zealand. There is no living. You just go backwards.
+You don't get a choice if you want to live, you have to move, or
+New Zealand has to change. I want a future for my children and there
+is none in New Zealand," she says. The New Zealand government has tried
+to increase some short-term measures like fuel subsidies and halving the cost
+of public transport - but for many, it's not enough.
+In Brescia, Italy, steel runs through the veins of the community.
+In the past 15 years the industry has endured the financial crash and
+the Covid-19 pandemic. Now, with the war in Ukraine and Covid lockdowns in China,
+trade is being disrupted further. Mirella and Lucas met at a cast iron
+foundry in Brescia. Their two steady wages are up against rising food, petrol
+and energy costs. "With regard to electricity, we have recently suffered
+like everyone else. Our bill has doubled - even though we are never at home",
+says Mirella. "We are tightening our belts. Instead of saving a lot,
+you'll save less," says Lucas. Orders at this cast iron foundry continue.
+But a crucial source of raw materials from the south-eastern Ukrainian city of
+Mariupol are in now short supply, after Russian troops occupied the region.
+Mark Impraim owns a catering business in Ghana - one of the most expensive
+countries to live in, in Africa. He shops for ingredients for one of his most
+popular dishes -jollof rice - at a local market. But prices have doubled
+in recent months. Mark looks at a bucket of tomatoes, dismayed at the price tag.
+"[This box of tomatoes] used to be 20 cedis. Now it's going for 40," he says.
+"I should double the price of the food I serve, but that would scare away customers.
+I try to find a way around it by decreasing the quantity."
+Among other rising costs eating into Mark's weekly budget is a supply
+of drinking water. Sachets of water have increased in price twice in four months,
+due to the devaluation of the cedi.
+Water suppliers say passing the costs on to customers is unavoidable.

Lab04/content/part1/encrypt/main.go

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+package main
+
+import (
+	"flag"
+	"io/ioutil"
+	"log"
+	"os"
+	"regexp"
+	"strings"
+	"unicode"
+)
+
+const lettersInTheAlphabet = 26
+const startUpperCase = 65
+const endUpperCase = startUpperCase + lettersInTheAlphabet
+const startLowerCase = 97
+const endLowerCase = startLowerCase + lettersInTheAlphabet
+
+type keyLetter struct {
+	upperCase string
+	position  int32
+}
+
+func parseArguments() (string, string) {
+	var inputKey string
+	var inputFile string
+	flag.StringVar(&inputKey, "k", "", "Specify key word.")
+	flag.StringVar(&inputFile, "f", "", "Specify file to encrypt.")
+	flag.Parse()
+	return inputKey, inputFile
+}
+
+func readFile(relativePath string) string {
+	content, err := ioutil.ReadFile(relativePath)
+	if err != nil {
+		log.Fatalln(err)
+	}
+	return string(content)
+}
+
+func writeFile(relativePath string, message string) {
+	file, err := os.Create(relativePath)
+	if err != nil {
+		log.Fatalln(err)
+	}
+	defer file.Close()
+	file.WriteString(message)
+}
+
+func validateKeyWord(inputKey string) string {
+	reg, err := regexp.Compile("[^a-zA-Z]+")
+	if err != nil {
+		log.Fatalln(err)
+	}
+	processedString := reg.ReplaceAllString(inputKey, "")
+	return strings.ToUpper(processedString)
+}
+
+func initKeyWord(key string) []keyLetter {
+	var keyWord []keyLetter
+	for _, letter := range key {
+		keyWord = append(keyWord, keyLetter{
+			upperCase: string(letter),
+			position:  letter - 'A',
+		})
+	}
+	return keyWord
+}
+
+func encryptMessage(keyWord []keyLetter, message string) string {
+	encrypted := ""
+	index := 0
+	for _, letter := range message {
+		if !unicode.IsLetter(letter) {
+			encrypted += string(letter)
+		} else {
+			keyWordIndex := index % len(keyWord)
+			newLetter := letter + keyWord[keyWordIndex].position
+			if (unicode.IsLower(letter) && newLetter >= endLowerCase) ||
+				(unicode.IsUpper(letter) && newLetter >= endUpperCase) {
+				newLetter -= lettersInTheAlphabet
+			}
+			encrypted += string(newLetter)
+			index += 1
+		}
+	}
+	return encrypted
+}
+
+func main() {
+	inputKey, inputFile := parseArguments()
+	message := readFile(inputFile)
+	keyWord := initKeyWord(validateKeyWord(inputKey))
+	writeFile("output.txt", encryptMessage(keyWord, message))
+}

Lab04/content/part1/encrypt/makefile

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+# Go parameters
+GoCMD=go
+GoBUILD=$(GoCMD) build
+GoCLEAN=$(GoCMD) clean
+GoTEST=$(GoCMD) test
+GoMOD=$(GoCMD) mod
+BINARY_NAME=tool
+
+# To install GoLang please follow the installation instructions on https://go.dev/
+all: build
+build:
+	$(GoBUILD) -o $(BINARY_NAME) -v
+clean:
+	$(GOCLEAN)
+	rm -f $(BINARY_NAME)
+deps:
+	$(GoMOD) tidy

Lab04/content/part1/encrypt/output.txt

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+Spk Qmayhbv'k hldzbay, Dsddnyukwn, uhg twjy frvkrk cfw tq hym lrhgl skqcilaoss
+uaytsj qn gos ogwwr wwr obmafl l diwpryhq. Lmp dzkthys ak fwgf orvt tgj wpbkmrf,
+dwlz f 12% cwjm ia wfaujd we bhr wokl dpoi. Bhna, odgsr kzbh vuqjwfdsj qn clhjgq
+lbu nobk djahpg, yis ylr essj hf koazwvww xcmqnt ac fwfcpp Iufafsdnl -
+kymrr avwq mljv bhr ywyzy ec cqvr hbv otcy.
+Tprvz, o tmnwrvz, hvz dsjyysi Paetcfq fyr kpevy tgmw oolohglfk jjnsebll ssxl
+Bpzcqntacf lt dhrzt n uso dnqs zv tul Omkycocqaa jwlq tq Piqsohbw.
+Vjddzbe bdbafl evvqr uvaw sso srznvuu jwfdceibyl gsdfcwva, tulm owwp gkqly zhjmlrzzvg.
+"Jl vsnj qclz kvkg, kg ne kra ekwsfkngs. Nm'd avhauj Lijbrnswsfx dopqnt fcm cszk kpe
+pvgl gk wwmqnt pg ygnyu lx - bha hzsy hoj bhr jckl ktjv genyg syt tb Emw Mlodsso,"
+grgs Pofak. Qpomqnt Uso Rjlzrvd nur lzj csjb os osj xfxwcg wnz o
+vakqwtclg ksuaxtce noe Oojetym. Sct fos ksdd hym mbcs osx ystmsfhfq xtc hym cupzvjjy.
+"Mfc cnu'h espp o cqvvuu af Spk Qmayhbv. Lmpfv qs av zannyu. Pwu wbgl yt motswnyrk.
+Qtf rfv't tlh s umzwtm is fcm ofyh kw lvcs, qgz somm tb tcnw, tc
+Bve Zrhzsfi soj bo poofyj. T krvt n milmwp tfz ml jvadicse inq avwjj
+tg ewnr pb Fwb Ksrtaak," gzw xlmj. Bhr Uso Rjlzrvd tvjwjsxseb hnz hjajo
+hf qnpysskj dcdm suvfl-ljca dmafbfwk qtyv nurs gmtxtrzms nur zsqgweo tul qgky
+zt gcbypq ljfyggwrg - iil xtc arvy, va'g fgy pbfcgu.
+Pb Tjjdqzi, Ighzq, kypsc zuaz hzjtfuy bhr csafx zt kpe pvaemsthp.
+Qn gos hsxe 15 mvirf avw asoijbrl ook wsoiimd gos xaslbtqay jfskm lbu
+bhr Jcnai-19 aoelezpq. Fgb, hwkp tul ksj ny Ibzavus sfi Ncmqd yvqcvthbj qn Powfs,
+ycoum if isafl owjzucasv xzchymr. Zpfwdql oel Lhjok eje ok i cnzh ajty
+tfcnqym af Gcsjkin. Avwaw ekf atrhrq ofrsj irr bd syftbjb rvzwfy kzcu, xegycd
+sso semrtf qgkyd. "Kzbh elusji ec vtepafaunem, nm hncs jwhpbkty fbtxwwpr
+cqkr ljwjdzbv mlfl. Cmj gtzc paf kcmtqpr - vdea avgmls kv irr usnww lh ywmr",
+zoqk Rtfvtln. "Ds sjj ewxptruwfy tff smlgz. Wfkypou wf fhjafl l zfb,
+ybb'zd kfgs cmsf," zoqk Qfqra. Oeksjk fe hyqs phgl awzb wwuakfq utyhzvur.
+Iil s hcitqay zcmjhp cw zaj tolwwtoca feva lzj dclbh-rhglwwy Ibzavuwsf hthp wf
+Zhfamuzz rze vu bgo xscib shwddq, fqhvz Rhzgass effwpf vqumutsu bhr ysyaty.
+Arzk Vtdjsnx cnvs n jolwwtbx jufpbwkx tb Xpaah - cfw tq hym mbzh wpupbjqvr
+jcmfycwva tb swnw ny, we Ifepqs. Zj dvfxs svf aflcsuqeaag xgw zbv wf upg egxe
+dfxuyhf vaxssj -royscx jnns - rb a yvqsd rlfbmt. Obh hjnnsj pail rgmgwsu
+qn elqwfy xcebhf. Tojc qzcba ag h pmupph fn tbtolgjd, rzamnfsv sy evv xrvjs lsl.
+"[Evza bbe cx ltxokwef] bgwv yz pv 20 keqpg. Fgb th'j oovuu xgw 40," ss jiyf.
+"P gzgzwr uwuoss lzj afzke bm hzw kzcu Q sryjw, tze hyit jvidv xnoim ajhm umxecdmrf.
+P hjq yz tzvd n doq swziel ig im vwhcsraian hzw vfoebigf."
+Oegsr ckpee ywkasr qfatf lolasr webo Zhfc'k bpsbty obrywy tg r aucwzq
+gk ofzvkvuu osypf. Jiculhk gk hokmr uhjw asnfvisrk wf hwtqv bwvjs af kzii uoaavk,
+vzp hf bhr ksnsqfokqoa vt lzj nsuq.
+Wnasj kzadcqeez gsq ulgjqnt avw utdhj wn gv qmkyzavzs vz ifsazwuibyl.