-
Notifications
You must be signed in to change notification settings - Fork 13
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
- Loading branch information
Showing
17 changed files
with
5,061 additions
and
7 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,300 @@ | ||
| /* | ||
| * BsDiff.cs for deltaq | ||
| * Copyright (c) 2014 J. Zebedee | ||
| * | ||
| * BsDiff.net is Copyright 2010 Logos Bible Software | ||
| * | ||
| * 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.Collections.Generic; | ||
| using System.IO; | ||
| using bz2core; | ||
| using deltaq.SuffixSort; | ||
|
|
||
| namespace deltaq.BsDiff | ||
| { | ||
| public static class BsDiff | ||
| { | ||
| internal const int HeaderSize = 32; | ||
| internal const long Signature = 0x3034464649445342; //"BSDIFF40" | ||
|
|
||
| private static ISuffixSort DefaultSuffixSort => new SAIS(); | ||
|
|
||
| internal static Stream GetEncodingStream(Stream stream, bool output) | ||
| { | ||
| if (output) | ||
| return new BZip2OutputStream(stream) { IsStreamOwner = false }; | ||
| return new BZip2InputStream(stream); | ||
| } | ||
|
|
||
| /// <summary> | ||
| /// Creates a BSDIFF-format patch from two byte arrays | ||
| /// </summary> | ||
| /// <param name="oldData">Byte array of the original (older) data</param> | ||
| /// <param name="newData">Byte array of the changed (newer) data</param> | ||
| /// <param name="output">Seekable, writable stream where the patch will be written</param> | ||
| /// <param name="suffixSort">Suffix sort implementation to use for comparison, or null to use a default sorter</param> | ||
| public static void Create(byte[] oldData, byte[] newData, Stream output, ISuffixSort suffixSort = null) | ||
| { | ||
| CreateInternal(oldData, newData, output, suffixSort ?? DefaultSuffixSort); | ||
| } | ||
|
|
||
| private static void CreateInternal(byte[] oldData, byte[] newData, Stream output, ISuffixSort suffixSort) | ||
| { | ||
| // check arguments | ||
| if (oldData == null) | ||
| throw new ArgumentNullException(nameof(oldData)); | ||
| if (newData == null) | ||
| throw new ArgumentNullException(nameof(newData)); | ||
| if (output == null) | ||
| throw new ArgumentNullException(nameof(output)); | ||
| if (suffixSort == null) | ||
| throw new ArgumentNullException(nameof(suffixSort)); | ||
| if (!output.CanSeek) | ||
| throw new ArgumentException("Output stream must be seekable.", nameof(output)); | ||
| if (!output.CanWrite) | ||
| throw new ArgumentException("Output stream must be writable.", nameof(output)); | ||
|
|
||
| /* Header is | ||
| 0 8 "BSDIFF40" | ||
| 8 8 length of bzip2ed ctrl block | ||
| 16 8 length of bzip2ed diff block | ||
| 24 8 length of new file | ||
| File is | ||
| 0 32 Header | ||
| 32 ?? Bzip2ed ctrl block | ||
| ?? ?? Bzip2ed diff block | ||
| ?? ?? Bzip2ed extra block */ | ||
| var header = new byte[HeaderSize]; | ||
| header.WriteLong(Signature); | ||
| header.WriteLongAt(24, newData.Length); | ||
|
|
||
| var startPosition = output.Position; | ||
| output.Write(header, 0, header.Length); | ||
|
|
||
| var I = suffixSort.Sort(oldData); | ||
|
|
||
| using (var msControl = new MemoryStream()) | ||
| using (var msDiff = new MemoryStream()) | ||
| using (var msExtra = new MemoryStream()) | ||
| { | ||
| using (var ctrlStream = GetEncodingStream(msControl, true)) | ||
| using (var diffStream = GetEncodingStream(msDiff, true)) | ||
| using (var extraStream = GetEncodingStream(msExtra, true)) | ||
| { | ||
| var scan = 0; | ||
| var pos = 0; | ||
| var len = 0; | ||
| var lastscan = 0; | ||
| var lastpos = 0; | ||
| var lastoffset = 0; | ||
|
|
||
| // compute the differences, writing ctrl as we go | ||
| while (scan < newData.Length) | ||
| { | ||
| var oldscore = 0; | ||
|
|
||
| for (var scsc = scan += len; scan < newData.Length; scan++) | ||
| { | ||
| len = Search(I, oldData, newData.Slice(scan), 0, oldData.Length, out pos); | ||
|
|
||
| for (; scsc < scan + len; scsc++) | ||
| { | ||
| if ((scsc + lastoffset < oldData.Length) && (oldData[scsc + lastoffset] == newData[scsc])) | ||
| oldscore++; | ||
| } | ||
|
|
||
| if ((len == oldscore && len != 0) || (len > oldscore + 8)) | ||
| break; | ||
|
|
||
| if ((scan + lastoffset < oldData.Length) && (oldData[scan + lastoffset] == newData[scan])) | ||
| oldscore--; | ||
| } | ||
|
|
||
| if (len != oldscore || scan == newData.Length) | ||
| { | ||
| var s = 0; | ||
| var sf = 0; | ||
| var lenf = 0; | ||
| for (var i = 0; (lastscan + i < scan) && (lastpos + i < oldData.Length); ) | ||
| { | ||
| if (oldData[lastpos + i] == newData[lastscan + i]) | ||
| s++; | ||
| i++; | ||
| if (s * 2 - i > sf * 2 - lenf) | ||
| { | ||
| sf = s; | ||
| lenf = i; | ||
| } | ||
| } | ||
|
|
||
| var lenb = 0; | ||
| if (scan < newData.Length) | ||
| { | ||
| s = 0; | ||
| var sb = 0; | ||
| for (var i = 1; (scan >= lastscan + i) && (pos >= i); i++) | ||
| { | ||
| if (oldData[pos - i] == newData[scan - i]) | ||
| s++; | ||
| if (s * 2 - i > sb * 2 - lenb) | ||
| { | ||
| sb = s; | ||
| lenb = i; | ||
| } | ||
| } | ||
| } | ||
|
|
||
| if (lastscan + lenf > scan - lenb) | ||
| { | ||
| var overlap = (lastscan + lenf) - (scan - lenb); | ||
| s = 0; | ||
| var ss = 0; | ||
| var lens = 0; | ||
| for (var i = 0; i < overlap; i++) | ||
| { | ||
| if (newData[lastscan + lenf - overlap + i] == oldData[lastpos + lenf - overlap + i]) | ||
| s++; | ||
| if (newData[scan - lenb + i] == oldData[pos - lenb + i]) | ||
| s--; | ||
| if (s > ss) | ||
| { | ||
| ss = s; | ||
| lens = i + 1; | ||
| } | ||
| } | ||
|
|
||
| lenf += lens - overlap; | ||
| lenb -= lens; | ||
| } | ||
|
|
||
| //write diff string | ||
| for (var i = 0; i < lenf; i++) | ||
| diffStream.WriteByte((byte)(newData[lastscan + i] - oldData[lastpos + i])); | ||
|
|
||
| //write extra string | ||
| var extraLength = (scan - lenb) - (lastscan + lenf); | ||
| if (extraLength > 0) | ||
| extraStream.Write(newData, lastscan + lenf, extraLength); | ||
|
|
||
| //backing for ctrl writes | ||
| var buf = new byte[8]; | ||
|
|
||
| //write ctrl block | ||
| buf.WriteLong(lenf); | ||
| ctrlStream.Write(buf, 0, 8); | ||
|
|
||
| buf.WriteLong(extraLength); | ||
| ctrlStream.Write(buf, 0, 8); | ||
|
|
||
| buf.WriteLong((pos - lenb) - (lastpos + lenf)); | ||
| ctrlStream.Write(buf, 0, 8); | ||
|
|
||
| lastscan = scan - lenb; | ||
| lastpos = pos - lenb; | ||
| lastoffset = pos - scan; | ||
| } | ||
| } | ||
| } | ||
|
|
||
| //write compressed ctrl data | ||
| msControl.Seek(0, SeekOrigin.Begin); | ||
| msControl.CopyTo(output); | ||
|
|
||
| // compute size of compressed ctrl data | ||
| header.WriteLongAt(8, msControl.Length); | ||
|
|
||
| // write compressed diff data | ||
| msDiff.Seek(0, SeekOrigin.Begin); | ||
| msDiff.CopyTo(output); | ||
|
|
||
| // compute size of compressed diff data | ||
| header.WriteLongAt(16, msDiff.Length); | ||
|
|
||
| // write compressed extra data | ||
| msExtra.Seek(0, SeekOrigin.Begin); | ||
| msExtra.CopyTo(output); | ||
| } | ||
|
|
||
| // seek to the beginning, write the header, then seek back to end | ||
| var endPosition = output.Position; | ||
| output.Position = startPosition; | ||
| output.Write(header, 0, header.Length); | ||
| output.Position = endPosition; | ||
| } | ||
|
|
||
| private static int CompareBytes(IList<byte> left, IList<byte> right) | ||
| { | ||
| var diff = 0; | ||
| for (var i = 0; i < left.Count && i < right.Count; i++) | ||
| { | ||
| diff = left[i] - right[i]; | ||
| if (diff != 0) | ||
| break; | ||
| } | ||
| return diff; | ||
| } | ||
|
|
||
| private static int MatchLength(IList<byte> oldData, IList<byte> newData) | ||
| { | ||
| int i; | ||
| for (i = 0; i < oldData.Count && i < newData.Count; i++) | ||
| { | ||
| if (oldData[i] != newData[i]) | ||
| break; | ||
| } | ||
|
|
||
| return i; | ||
| } | ||
|
|
||
| private static int Search(IList<int> I, byte[] oldData, IList<byte> newData, int start, int end, out int pos) | ||
| { | ||
| while (true) | ||
| { | ||
| if (end - start < 2) | ||
| { | ||
| var startLength = MatchLength(oldData.Slice(I[start]), newData); | ||
| var endLength = MatchLength(oldData.Slice(I[end]), newData); | ||
|
|
||
| if (startLength > endLength) | ||
| { | ||
| pos = I[start]; | ||
| return startLength; | ||
| } | ||
|
|
||
| pos = I[end]; | ||
| return endLength; | ||
| } | ||
|
|
||
| var midPoint = start + (end - start) / 2; | ||
| if (CompareBytes(oldData.Slice(I[midPoint]), newData) < 0) | ||
| { | ||
| start = midPoint; | ||
| continue; | ||
| } | ||
|
|
||
| end = midPoint; | ||
| } | ||
| } | ||
| } | ||
| } |
Oops, something went wrong.