Merge pull request #2 from timersha/hw02_unpack_string

HW2 is completed
timersha · Jan 1, 2025 · da3bb9d · da3bb9d
2 parents 5e1ffa6 + 324200a
commit da3bb9d
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Showing 6 changed files with 124 additions and 18 deletions.
diff --git a/hw02_unpack_string/.golangci.yml b/hw02_unpack_string/.golangci.yml
@@ -0,0 +1,16 @@
+linters-settings:
+  depguard:
+    rules:
+      Main:
+        files:
+          - $all
+          - "!$test"
+        allow:
+          - $gostd
+          - github.com/stretchr/testify/require
+      Test:
+        files:
+          - $test
+        allow:
+          - $gostd
+          - github.com/stretchr/testify
diff --git a/hw02_unpack_string/.sync b/hw02_unpack_string/.sync
diff --git a/hw02_unpack_string/go.mod b/hw02_unpack_string/go.mod
@@ -1,11 +1,11 @@
-module github.com/fixme_my_friend/hw02_unpack_string
+module github.com/timersha/golang-tests/hw02_unpack_string
 
-go 1.22
+go 1.22.0
 
-require github.com/stretchr/testify v1.7.0
+require github.com/stretchr/testify v1.10.0
 
 require (
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
-	gopkg.in/yaml.v3 v3.0.0-20210107192922-496545a6307b // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
 )
diff --git a/hw02_unpack_string/go.sum b/hw02_unpack_string/go.sum
@@ -1,13 +1,10 @@
-github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
-github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
-github.com/stretchr/testify v1.7.0 h1:nwc3DEeHmmLAfoZucVR881uASk0Mfjw8xYJ99tb5CcY=
-github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+github.com/stretchr/testify v1.10.0 h1:Xv5erBjTwe/5IxqUQTdXv5kgmIvbHo3QQyRwhJsOfJA=
+github.com/stretchr/testify v1.10.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
-gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
-gopkg.in/yaml.v3 v3.0.0-20210107192922-496545a6307b h1:h8qDotaEPuJATrMmW04NCwg7v22aHH28wwpauUhK9Oo=
-gopkg.in/yaml.v3 v3.0.0-20210107192922-496545a6307b/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
diff --git a/hw02_unpack_string/unpack.go b/hw02_unpack_string/unpack.go
@@ -2,11 +2,104 @@ package hw02unpackstring
 
 import (
 	"errors"
+	"fmt"
+	"math"
+	"strconv"
+	"unicode"
+	"unicode/utf8"
 )
 
 var ErrInvalidString = errors.New("invalid string")
 
-func Unpack(_ string) (string, error) {
-	// Place your code here.
-	return "", nil
+func Unpack(str string) (string, error) {
+	inputIndex := 0
+	resultIndex := 0
+	backslash := '\\'
+	input := []rune(str)
+	result := make([]rune, 0, 200)
+	inputLen := len(input) - 1
+
+	// validate length
+	if utf8.RuneCountInString(string(input)) == 0 {
+		return "", nil
+	}
+
+	// starts with digit
+	if unicode.IsDigit(input[0]) {
+		return "", ErrInvalidString
+	}
+
+	for inputIndex <= inputLen {
+		r := input[inputIndex]
+
+		inputNextIndex := nextIndex(&input, inputIndex)
+		nextR := input[inputNextIndex]
+		// finds number
+		if inputLen != inputNextIndex && unicode.IsDigit(r) && unicode.IsDigit(nextR) {
+			fmt.Println("finds number")
+			return "", ErrInvalidString
+		}
+
+		// escaped symbol is valid
+		isValidForEscape := unicode.IsDigit(nextR) || nextR == backslash
+		if r == backslash && isValidForEscape {
+			result = append(result, nextR)
+			resultIndex++
+			inputIndex += 2
+			continue
+		}
+
+		// escaped symbol is not valid
+		if r == backslash && !isValidForEscape {
+			fmt.Println("escaped symbol is not valid")
+			return "", ErrInvalidString
+		}
+
+		// repeatedly add rune
+		isDigit := unicode.IsDigit(r)
+		if isDigit {
+			shift := appendRune(&result, result[previousIndex(&result, resultIndex)], r)
+			resultIndex += shift
+			inputIndex++
+			continue
+		}
+
+		// remove current rune
+		vl, err := strconv.Atoi(string(nextR))
+		if err == nil && vl == 0 {
+			inputIndex++
+			continue
+		}
+
+		// simple append
+		result = append(result, r)
+		resultIndex++
+		inputIndex++
+	}
+
+	return string(result), nil
+}
+
+func appendRune(res *[]rune, rn rune, count rune) int {
+	value, err := strconv.Atoi(string(count))
+	if err != nil {
+		return 0
+	}
+
+	for range value - 1 {
+		*res = append(*res, rn)
+	}
+	return value
+}
+
+func nextIndex(sl *[]rune, index int) int {
+	slLen := math.Max(0, float64(len(*sl)-1))
+	nextIndex := index + 1
+	return int(math.Min(float64(slLen), float64(nextIndex)))
+}
+
+func previousIndex(sl *[]rune, index int) int {
+	slLen := math.Max(0, float64(len(*sl)-1))
+	previousIndex := index - 1
+	return int(math.Min(float64(slLen), math.Max(0, float64(previousIndex))))
 }
diff --git a/hw02_unpack_string/unpack_test.go b/hw02_unpack_string/unpack_test.go
@@ -17,10 +17,10 @@ func TestUnpack(t *testing.T) {
 		{input: "", expected: ""},
 		{input: "aaa0b", expected: "aab"},
 		// uncomment if task with asterisk completed
-		// {input: `qwe\4\5`, expected: `qwe45`},
-		// {input: `qwe\45`, expected: `qwe44444`},
-		// {input: `qwe\\5`, expected: `qwe\\\\\`},
-		// {input: `qwe\\\3`, expected: `qwe\3`},
+		{input: `qwe\4\5`, expected: `qwe45`},
+		{input: `qwe\45`, expected: `qwe44444`},
+		{input: `qwe\\5`, expected: `qwe\\\\\`},
+		{input: `qwe\\\3`, expected: `qwe\3`},
 	}
 
 	for _, tc := range tests {