Use a different rope implementation

src/buffer.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"github.com/vinzmay/go-rope"
 	"io/ioutil"
 	"strings"
 )
@@ -10,7 +11,7 @@ import (
 // simple functions for saving and wrapper functions for modifying the rope
 type Buffer struct {
 	// Stores the text of the buffer
-	r *Rope
+	r *rope.Rope
 
 	// Path to the file on disk
 	path string
@@ -35,7 +36,11 @@ type Buffer struct {
 // NewBuffer creates a new buffer from `txt` with path and name `path`
 func NewBuffer(txt, path string) *Buffer {
 	b := new(Buffer)
-	b.r = NewRope(txt)
+	if txt == "" {
+		b.r = new(rope.Rope)
+	} else {
+		b.r = rope.New(txt)
+	}
 	b.path = path
 	b.name = path
 	b.savedText = txt
@@ -54,7 +59,11 @@ func (b *Buffer) UpdateRules() {
 
 // Update fetches the string from the rope and updates the `text` and `lines` in the buffer
 func (b *Buffer) Update() {
-	b.text = b.r.String()
+	if b.r.Len() == 0 {
+		b.text = ""
+	} else {
+		b.text = b.r.String()
+	}
 	b.lines = strings.Split(b.text, "\n")
 }
 
@@ -79,7 +88,7 @@ func (b *Buffer) IsDirty() bool {
 
 // Insert a string into the rope
 func (b *Buffer) Insert(idx int, value string) {
-	b.r.Insert(idx, value)
+	b.r = b.r.Insert(idx, value)
 	b.Update()
 }
 
@@ -93,12 +102,15 @@ func (b *Buffer) Remove(start, end int) string {
 		end = b.Len()
 	}
 	removed := b.text[start:end]
-	b.r.Remove(start, end)
+	// The rope implenentation I am using wants indicies starting at 1 instead of 0
+	start++
+	end++
+	b.r = b.r.Delete(start, end-start)
 	b.Update()
 	return removed
 }
 
 // Len gives the length of the buffer
 func (b *Buffer) Len() int {
-	return b.r.len
+	return b.r.Len()
 }

src/rope.go

@@ -1,105 +0,0 @@
-package main
-
-import (
-	"math"
-)
-
-const (
-	// RopeSplitLength is the threshold used to split a leaf node into two child nodes.
-	RopeSplitLength = 1000000000
-	// RopeJoinLength is the threshold used to join two child nodes into one leaf node.
-	RopeJoinLength = 500
-	// RopeRebalanceRatio = 1.2
-)
-
-// A Rope is a data structure for efficiently manipulating large strings
-type Rope struct {
-	left     *Rope
-	right    *Rope
-	value    string
-	valueNil bool
-
-	len int
-}
-
-// NewRope returns a new rope from a given string
-func NewRope(str string) *Rope {
-	r := new(Rope)
-	r.value = str
-	r.valueNil = false
-	r.len = Count(r.value)
-
-	r.Adjust()
-
-	return r
-}
-
-// Adjust modifies the rope so it is more balanced
-func (r *Rope) Adjust() {
-	if !r.valueNil {
-		if r.len > RopeSplitLength {
-			divide := int(math.Floor(float64(r.len) / 2))
-			runes := []rune(r.value)
-			r.left = NewRope(string(runes[:divide]))
-			r.right = NewRope(string(runes[divide:]))
-			r.valueNil = true
-		}
-	} else {
-		if r.len < RopeJoinLength {
-			r.value = r.left.String() + r.right.String()
-			r.valueNil = false
-			r.left = nil
-			r.right = nil
-		}
-	}
-}
-
-// String returns the string representation of the rope
-func (r *Rope) String() string {
-	if !r.valueNil {
-		return r.value
-	}
-	return r.left.String() + r.right.String()
-}
-
-// Remove deletes a slice of the rope from start the to end (exclusive)
-func (r *Rope) Remove(start, end int) {
-	if !r.valueNil {
-		r.value = string(append([]rune(r.value)[:start], []rune(r.value)[end:]...))
-		r.valueNil = false
-		r.len = Count(r.value)
-	} else {
-		leftStart := Min(start, r.left.len)
-		leftEnd := Min(end, r.left.len)
-		rightStart := Max(0, Min(start-r.left.len, r.right.len))
-		rightEnd := Max(0, Min(end-r.left.len, r.right.len))
-		if leftStart < r.left.len {
-			r.left.Remove(leftStart, leftEnd)
-		}
-		if rightEnd > 0 {
-			r.right.Remove(rightStart, rightEnd)
-		}
-		r.len = r.left.len + r.right.len
-	}
-
-	r.Adjust()
-}
-
-// Insert inserts a string into the rope at a specified position
-func (r *Rope) Insert(pos int, value string) {
-	if !r.valueNil {
-		first := append([]rune(r.value)[:pos], []rune(value)...)
-		r.value = string(append(first, []rune(r.value)[pos:]...))
-		r.valueNil = false
-		r.len = Count(r.value)
-	} else {
-		if pos < r.left.len {
-			r.left.Insert(pos, value)
-			r.len = r.left.len + r.right.len
-		} else {
-			r.right.Insert(pos-r.left.len, value)
-		}
-	}
-
-	r.Adjust()
-}

src/rope_test.go

@@ -1,46 +0,0 @@
-package main
-
-import "testing"
-
-func TestInsert(t *testing.T) {
-	var tests = []struct {
-		origStr   string
-		insertStr string
-		insertPos int
-		want      string
-	}{
-		{"foo", " bar", 3, "foo bar"},
-		{"üñîç", "ø∂é", 4, "üñîçø∂é"},
-		{"test", "3", 2, "te3st"},
-		{"", "test", 0, "test"},
-	}
-	for _, test := range tests {
-		r := NewRope(test.origStr)
-		r.Insert(test.insertPos, test.insertStr)
-		got := r.String()
-		if got != test.want {
-			t.Errorf("Insert(%d, %s) = %s", test.insertPos, test.insertStr, got)
-		}
-	}
-}
-
-func TestRemove(t *testing.T) {
-	var tests = []struct {
-		inputStr    string
-		removeStart int
-		removeEnd   int
-		want        string
-	}{
-		{"foo bar", 3, 7, "foo"},
-		{"üñîçø∂é", 0, 3, "çø∂é"},
-		{"test", 0, 4, ""},
-	}
-	for _, test := range tests {
-		r := NewRope(test.inputStr)
-		r.Remove(test.removeStart, test.removeEnd)
-		got := r.String()
-		if got != test.want {
-			t.Errorf("Remove(%d, %d) = %s", test.removeStart, test.removeEnd, got)
-		}
-	}
-}