Added FindFirst,FindLast,FindAll

Author: linkdotnet

CHANGELOG.md

@@ -6,6 +6,9 @@ All notable changes to **ValueStringBuilder** will be documented in this file. T
 
 ## [Unreleased]
 
+### Added
+- Added the following methods: `FindFirst`, `FindLast`, `FindAll`
+
 ## [0.3.0] - 2022-12-25
 
 ### Added

search.go

@@ -0,0 +1,73 @@
+package Text
+
+// Returns all occurences of needle in haystack
+func findAll(haystack []rune, needle string) []int {
+
+	if len(haystack) == 0 || len(needle) == 0 || len(needle) > len(haystack) {
+		return []int{}
+	}
+
+	items := make([]int, 0, 8)
+
+	for i := 0; i < len(haystack); i++ {
+		for j := 0; j < len(needle); j++ {
+			if haystack[i+j] != rune(needle[j]) {
+				break
+			}
+
+			if j == len(needle)-1 {
+				items = append(items, i)
+			}
+		}
+	}
+
+	return items
+}
+
+// Returns the first occurrence of haystack in needle or -1 if not found.
+func findFirst(haystack []rune, needle string) int {
+	if len(haystack) == 0 || len(needle) == 0 || len(needle) > len(haystack) {
+		return -1
+	}
+
+	lenHaystack := len(haystack)
+	lenNeedle := len(needle)
+
+	for i := 0; i <= lenHaystack-lenNeedle; i++ {
+		for j := 0; j < lenNeedle; j++ {
+			if haystack[i+j] != rune(needle[j]) {
+				break
+			}
+
+			if j == lenNeedle-1 {
+				return i
+			}
+		}
+	}
+
+	return -1
+}
+
+// Returns the last occurrence of haystack in needle or -1 if not found.
+func findLast(haystack []rune, needle string) int {
+	if len(haystack) == 0 || len(needle) == 0 || len(needle) > len(haystack) {
+		return -1
+	}
+
+	lenHaystack := len(haystack)
+	lenNeedle := len(needle)
+
+	for i := lenHaystack - lenNeedle + 1; i >= 0; i-- {
+		for j := 0; j < lenNeedle; j++ {
+			if haystack[i+j] != rune(needle[j]) {
+				break
+			}
+
+			if j == lenNeedle-1 {
+				return i
+			}
+		}
+	}
+
+	return -1
+}

stringbuilder.go

@@ -121,6 +121,21 @@ func (s *StringBuilder) AsRune() []rune {
 	return s.data[:s.position]
 }
 
+// Returns the first occurrence of the given text in the string builder. Returns -1 if not found
+func (s *StringBuilder) FindFirst(text string) int {
+	return findFirst(s.AsRune(), text)
+}
+
+// Returns the last occurrence of the given text in the string builder. Returns -1 if not found
+func (s *StringBuilder) FindLast(text string) int {
+	return findLast(s.AsRune(), text)
+}
+
+// Returns all occurrences of the given text in the string builder. Returns an empty if no occurrence found.
+func (s *StringBuilder) FindAll(text string) []int {
+	return findAll(s.AsRune(), text)
+}
+
 func (s *StringBuilder) grow(lenToAdd int) {
 	// Grow times 2 until lenToAdd fits
 	newLen := cap(s.data)

stringbuilder_test.go

@@ -192,3 +192,83 @@ func TestAppendRuneMultiple(t *testing.T) {
 		t.Errorf("Actual %q, Expected: %q", result, expected)
 	}
 }
+
+func TestFindFirst(t *testing.T) {
+	tests := []struct {
+		name   string
+		input  string
+		needle string
+		want   int
+	}{
+		{"Empty haystack", "", "n", -1},
+		{"Empty needle", "n", "", -1},
+		{"Needle longer than haystack", "a", "ab", -1},
+		{"Hello in Hello World", "Hello World", "Hello", 0},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			s := NewStringBuilderFromString(tt.input)
+			if got := s.FindFirst(tt.needle); got != tt.want {
+				t.Errorf("StringBuilder.FindFirst() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestFindLast(t *testing.T) {
+	tests := []struct {
+		name   string
+		input  string
+		needle string
+		want   int
+	}{
+		{"Empty haystack", "", "n", -1},
+		{"Empty needle", "n", "", -1},
+		{"Needle longer than haystack", "a", "ab", -1},
+		{"Hello in Hello World", "Hello World", "Hello", 0},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			s := NewStringBuilderFromString(tt.input)
+			if got := s.FindLast(tt.needle); got != tt.want {
+				t.Errorf("StringBuilder.FindLast() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestFindAll(t *testing.T) {
+	tests := []struct {
+		name   string
+		input  string
+		needle string
+		want   []int
+	}{
+		{"Empty haystack", "", "n", []int{}},
+		{"Empty needle", "n", "", []int{}},
+		{"Needle longer than haystack", "a", "ab", []int{}},
+		{"Hello in Hello World", "Hello World", "Hello", []int{0}},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			s := NewStringBuilderFromString(tt.input)
+			if got := s.FindAll(tt.needle); !slicesEqual(got, tt.want) {
+				t.Errorf("StringBuilder.FindLast() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func slicesEqual(a []int, b []int) bool {
+	if len(a) != len(b) {
+		return false
+	}
+
+	for i := 0; i < len(a); i++ {
+		if a[i] != b[i] {
+			return false
+		}
+	}
+
+	return true
+}