/AvalonEdit/ICSharpCode.AvalonEdit/Document/GapTextBuffer.cs
http://github.com/icsharpcode/ILSpy · C# · 207 lines · 7 code · 3 blank · 197 comment · 0 complexity · 86226131f1ec0526c6b8fcfe954643aa MD5 · raw file
- // Copyright (c) 2014 AlphaSierraPapa for the SharpDevelop Team
- //
- // Permission is hereby granted, free of charge, to any person obtaining a copy of this
- // software and associated documentation files (the "Software"), to deal in the Software
- // without restriction, including without limitation the rights to use, copy, modify, merge,
- // publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
- // to whom the Software is furnished to do so, subject to the following conditions:
- //
- // The above copyright notice and this permission notice shall be included in all copies or
- // substantial portions of the Software.
- //
- // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
- // INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
- // PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
- // FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
- // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
- // DEALINGS IN THE SOFTWARE.
- using System;
- using System.Diagnostics;
- using System.Text;
- using ICSharpCode.AvalonEdit.Utils;
- namespace ICSharpCode.AvalonEdit.Document
- {
- /*
- /// <summary>
- /// Implementation of a gap text buffer.
- /// </summary>
- sealed class GapTextBuffer
- {
- char[] buffer = Empty<char>.Array;
-
- /// <summary>
- /// The current text content.
- /// Is set to null whenever the buffer changes, and gets a value only when the
- /// full text content is requested.
- /// </summary>
- string textContent;
-
- /// <summary>
- /// last GetText result
- /// </summary>
- string lastGetTextResult;
- int lastGetTextRequestOffset;
-
- int gapBeginOffset;
- int gapEndOffset;
- int gapLength; // gapLength == gapEndOffset - gapBeginOffset
-
- /// <summary>
- /// when gap is too small for inserted text or gap is too large (exceeds maxGapLength),
- /// a new buffer is reallocated with a new gap of at least this size.
- /// </summary>
- const int minGapLength = 128;
-
- /// <summary>
- /// when the gap exceeds this size, reallocate a smaller buffer
- /// </summary>
- const int maxGapLength = 4096;
-
- public int Length {
- get {
- return buffer.Length - gapLength;
- }
- }
-
- /// <summary>
- /// Gets the buffer content.
- /// </summary>
- public string Text {
- get {
- if (textContent == null)
- textContent = GetText(0, Length);
- return textContent;
- }
- set {
- Debug.Assert(value != null);
- textContent = value; lastGetTextResult = null;
- buffer = new char[value.Length + minGapLength];
- value.CopyTo(0, buffer, 0, value.Length);
- gapBeginOffset = value.Length;
- gapEndOffset = buffer.Length;
- gapLength = gapEndOffset - gapBeginOffset;
- }
- }
-
- public char GetCharAt(int offset)
- {
- return offset < gapBeginOffset ? buffer[offset] : buffer[offset + gapLength];
- }
-
- public string GetText(int offset, int length)
- {
- if (length == 0)
- return string.Empty;
- if (lastGetTextRequestOffset == offset && lastGetTextResult != null && length == lastGetTextResult.Length)
- return lastGetTextResult;
-
- int end = offset + length;
- string result;
- if (end < gapBeginOffset) {
- result = new string(buffer, offset, length);
- } else if (offset > gapBeginOffset) {
- result = new string(buffer, offset + gapLength, length);
- } else {
- int block1Size = gapBeginOffset - offset;
- int block2Size = end - gapBeginOffset;
-
- StringBuilder buf = new StringBuilder(block1Size + block2Size);
- buf.Append(buffer, offset, block1Size);
- buf.Append(buffer, gapEndOffset, block2Size);
- result = buf.ToString();
- }
- lastGetTextRequestOffset = offset;
- lastGetTextResult = result;
- return result;
- }
-
- /// <summary>
- /// Inserts text at the specified offset.
- /// </summary>
- public void Insert(int offset, string text)
- {
- Debug.Assert(offset >= 0 && offset <= Length);
-
- if (text.Length == 0)
- return;
-
- textContent = null; lastGetTextResult = null;
- PlaceGap(offset, text.Length);
- text.CopyTo(0, buffer, gapBeginOffset, text.Length);
- gapBeginOffset += text.Length;
- gapLength = gapEndOffset - gapBeginOffset;
- }
-
- /// <summary>
- /// Remove <paramref name="length"/> characters at <paramref name="offset"/>.
- /// Leave a gap of at least <paramref name="reserveGapSize"/>.
- /// </summary>
- public void Remove(int offset, int length, int reserveGapSize)
- {
- Debug.Assert(offset >= 0 && offset <= Length);
- Debug.Assert(length >= 0 && offset + length <= Length);
- Debug.Assert(reserveGapSize >= 0);
-
- if (length == 0)
- return;
-
- textContent = null; lastGetTextResult = null;
- PlaceGap(offset, reserveGapSize - length);
- gapEndOffset += length; // delete removed text
- gapLength = gapEndOffset - gapBeginOffset;
- if (gapLength - reserveGapSize > maxGapLength && gapLength - reserveGapSize > buffer.Length / 4) {
- // shrink gap
- MakeNewBuffer(gapBeginOffset, reserveGapSize + minGapLength);
- }
- }
-
- void PlaceGap(int newGapOffset, int minRequiredGapLength)
- {
- if (gapLength < minRequiredGapLength) {
- // enlarge gap
- MakeNewBuffer(newGapOffset, minRequiredGapLength + Math.Max(minGapLength, buffer.Length / 8));
- } else {
- while (newGapOffset < gapBeginOffset) {
- buffer[--gapEndOffset] = buffer[--gapBeginOffset];
- }
- while (newGapOffset > gapBeginOffset) {
- buffer[gapBeginOffset++] = buffer[gapEndOffset++];
- }
- }
- }
-
- void MakeNewBuffer(int newGapOffset, int newGapLength)
- {
- char[] newBuffer = new char[Length + newGapLength];
- Debug.WriteLine("GapTextBuffer was reallocated, new size=" + newBuffer.Length);
- if (newGapOffset < gapBeginOffset) {
- // gap is moving backwards
-
- // first part:
- Array.Copy(buffer, 0, newBuffer, 0, newGapOffset);
- // moving middle part:
- Array.Copy(buffer, newGapOffset, newBuffer, newGapOffset + newGapLength, gapBeginOffset - newGapOffset);
- // last part:
- Array.Copy(buffer, gapEndOffset, newBuffer, newBuffer.Length - (buffer.Length - gapEndOffset), buffer.Length - gapEndOffset);
- } else {
- // gap is moving forwards
- // first part:
- Array.Copy(buffer, 0, newBuffer, 0, gapBeginOffset);
- // moving middle part:
- Array.Copy(buffer, gapEndOffset, newBuffer, gapBeginOffset, newGapOffset - gapBeginOffset);
- // last part:
- int lastPartLength = newBuffer.Length - (newGapOffset + newGapLength);
- Array.Copy(buffer, buffer.Length - lastPartLength, newBuffer, newGapOffset + newGapLength, lastPartLength);
- }
-
- gapBeginOffset = newGapOffset;
- gapEndOffset = newGapOffset + newGapLength;
- gapLength = newGapLength;
- buffer = newBuffer;
- }
- }
- */
- }