Patch Generator (c) 1994 Martin Mares, MJSoft System Software ================================================================================ Preface ======= PatchGen, PatchGenL, Patcher and their documentation are Copyright (c) Martin Mares, MJSoft System Software, Prague, Czech Republic. This archive can be freely redistributed as long as all of its files are included in their original form without any additions, deletions or modifications (excluding addition of other README-style files and icons) and no more than a nominal fee is charged for its distribution. All copyright notices in the programs and accompanying documentation files must remain intact. It's especially forbidden to add various '.displayme' files and BBS advertisements. This style of distribution is generally known as FREEWARE. The only exception to this rule is the Patcher executable which can be spread without any restrictions in its original unmodified form in any kind of software package (including commercial products). Source text of all programs is included in the distribution. You can freely improve it. If you want to distribute your improved version, there're two possibilities: (1) Send your improvements to me (the best form is a diff output) and I'll include them in the next release. (2) Distribute them alone. In this case, you must mention the name of original author, change the name of the product (not only by increasing the version), and obey all of the distribution rules mentioned above. This software is provided "AS IS" without warranty of any kind, either expressed or implied. The author is not responsible for any damage caused by it. Introduction ============ Many people distribute new versions of software. This task can be done in two significantly different ways: (1) Redistributing all files. This method is simple, the user has no need to have the older version to install the new one. But the archives are usually lengthy and consume much disk space. (2) Distribution of patches. When this method is used, only the differences between the previous version and the recent one are distributed. The updates require much less disk space, but the user needs to have the previous version. This turns out to be an advantage when distributing updates of commercial software, because the new version is available only to legal users which have the old one. Also third-party patches to commercial software can be spread this way legally. If you want to use the second method of distribution, you need some software to generate and apply the patches. There are already some patch generators (for example lpatch), but they're usually very slow, their size is not so small as it could be if they were written better and the products itself are big. The solution is ... PatchGen! PatchGen eliminates at least of the previously mentioned disadvantages -- its patch files are relatively short and the programs themself are very small and run under any version of AmigaDOS starting with 1.2 (I think it would work also under 1.1, but I have never seen this kickstart. If you have it, let me know!). Requirements ============ - Kickstart 1.2 or higher. - arp.library - it's required only by the patch generators. Patcher runs without it. - 68000 or higher Generating patches ================== There are two patch generators in this archive: PatchGen and PatchGenL. Both of them produce the same patch file format, but they use a slightly different algorithm. For small files, use PatchGen. For large files, PatchGenL could produce better results and might be faster. Usage: PatchGen[L] [CHANGE] - the older file - the newer file (PatchGen will produce a patch to create from . - file to write the patch table to CHANGE - in some cases, the versions are too different to get a patch table of reasonable size, but you _want_ to make the new file dependent on the old one (commercial software, grr!). In this case, specify the CHANGE option. The new file will be stored in simple way, but it will be encrypted by contents of the older file which makes it impossible to create the new file without having the old one. Some dots will be printed as a progress indicator. Warning: Creation of patch tables requires a lot of memory -- a size of plus two times size of . Applying patches ================ To apply the patches, enter: Patcher This command transforms to using given patch table produced by PatchGen or PatchGenL. The is checked to be the correct source file by comparing its checksum with the one stored in the patch file. Memory requirements: + + . (a lot of, grr!) History ======= This release has exactly the same programs as the first one had, only the source texts have been added. Notes ===== This program is not the best solution if searching for differences between two text files. In this case, it would be better to use GNU diff. Plans: - New version of Patcher eating less memory. - Faster searching algorithms. Send suggestions, bug reports and flames to .