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      1 /*-
      2  * Copyright 2003,2004 Colin Percival
      3  * All rights reserved
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted providing that the following conditions
      7  * are met:
      8  * 1. Redistributions of source code must retain the above copyright
      9  *    notice, this list of conditions and the following disclaimer.
     10  * 2. Redistributions in binary form must reproduce the above copyright
     11  *    notice, this list of conditions and the following disclaimer in the
     12  *    documentation and/or other materials provided with the distribution.
     13  *
     14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     15  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
     16  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
     18  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
     22  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
     23  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     24  * POSSIBILITY OF SUCH DAMAGE.
     25  *
     26  * Changelog:
     27  * 2005-04-26 - Define the header as a C structure, add a CRC32 checksum to
     28  *              the header, and make all the types 32-bit.
     29  *                --Benjamin Smedberg <benjamin (at) smedbergs.us>
     30  * 2009-03-31 - Change to use Streams.  Move CRC code to crc.{h,cc}
     31  *              Changed status to an enum, removed unused status codes.
     32  *                --Stephen Adams <sra (at) chromium.org>
     33  * 2013-04-10 - Added wrapper to apply a patch directly to files.
     34  *                --Joshua Pawlicki <waffles (at) chromium.org>
     35  */
     36 
     37 #ifndef COURGETTE_BSDIFF_H_
     38 #define COURGETTE_BSDIFF_H_
     39 
     40 #include "base/basictypes.h"
     41 #include "base/file_util.h"
     42 
     43 namespace courgette {
     44 
     45 enum BSDiffStatus {
     46   OK = 0,
     47   MEM_ERROR = 1,
     48   CRC_ERROR = 2,
     49   READ_ERROR = 3,
     50   UNEXPECTED_ERROR = 4,
     51   WRITE_ERROR = 5
     52 };
     53 
     54 class SourceStream;
     55 class SinkStream;
     56 
     57 // Creates a binary patch.
     58 //
     59 BSDiffStatus CreateBinaryPatch(SourceStream* old_stream,
     60                                SourceStream* new_stream,
     61                                SinkStream* patch_stream);
     62 
     63 // Applies the given patch file to a given source file. This method validates
     64 // the CRC of the original file stored in the patch file, before applying the
     65 // patch to it.
     66 //
     67 BSDiffStatus ApplyBinaryPatch(SourceStream* old_stream,
     68                               SourceStream* patch_stream,
     69                               SinkStream* new_stream);
     70 
     71 // As above, but simply takes the file paths.
     72 BSDiffStatus ApplyBinaryPatch(const base::FilePath& old_stream,
     73                               const base::FilePath& patch_stream,
     74                               const base::FilePath& new_stream);
     75 
     76 // The following declarations are common to the patch-creation and
     77 // patch-application code.
     78 
     79 // The patch stream starts with a MBSPatchHeader.
     80 typedef struct MBSPatchHeader_ {
     81   char tag[8];       // Contains MBS_PATCH_HEADER_TAG
     82   uint32 slen;       // Length of the file to be patched.
     83   uint32 scrc32;     // CRC32 of the file to be patched.
     84   uint32 dlen;       // Length of the result file.
     85 } MBSPatchHeader;
     86 
     87 // This is the value for the tag field.  Must match length exactly, not counting
     88 // null at end of string.
     89 #define MBS_PATCH_HEADER_TAG "GBSDIF42"
     90 
     91 }  // namespace
     92 #endif  // COURGETTE_BSDIFF_H_
     93