Atari Forever 2

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INTRODUCTION Purpose and Capabilities ARC (short for archive) is a file library and compression utility. It may be thought of as an improved version of LU and SQUEEZE all rolled into one program. ARC analyzes each file to see which of a number of compression techniques will generate the smallest code. The following estimates give the user a general idea of how much compression may be gained by using ARC. ARC Text - 45-55% reduction from original SQUEEZED Text - 30-40% reduction ARC Programs - 25-30% reduction SQUEEZED Programs - 15-20% reduction ARC Pictures - 45-55% reduction SQUEEZED Pictures - 40-50% reduction TINY Pictures - 40-50% reduction The user should see that compressing files with ARC will allow easier telecommunications by combining files and shortening their transfer time. Usage from TOS - double-click-left on ARC.TTP icon - observe OPEN APPLICATION menu for ARC.TTP parameters - enter switch, archive name and file template (ex: lh arc.arc *.*) - hit return or click-left on OK box to begin execution - "press any key to continue" after completion ARC was written to be used with a command shell rather than the desktop. The only difficulty associated with executing from the desktop is that the desktop reappears after execution, making it difficult to see what has been output to the screen. Usage from Micro C-Shell - observe the % prompt - type in command, switch, archive name and file template (ex: arc l arc.arc *.*) - hit return to begin execution - use CNTL-S and CNTL-Q keys as necessary to view text before it scrolls off the screen There is one complication to using ARC from the Beckemeyer C-Shell. When specifying file templates (ex: *.*), the C-Shell will look at the current directory and expand the template to the files matched. The problem arises because this template is intended to match files inside the archive library (.ARC file). There is a simple solution just surround the template with double quotes, this tells the C-Shell not to expand the template. History ARC has been in use in the CP/M and MS-DOS world for many years. Thom Henderson developed the version which I converted for use on the Atari ST. I am not sure but he may also be the original author. It is important to note that no matter who developed this program, ARC is based on the file compression theories developed by Huffman, Welch, Knott, Knuth, and many other scientists. Bug Reports Since I developed this version of ARC, I will be responsible for any erroneous features. Please relay any problems with a written discription of what happened and the .ARC file which caused the problem to: Harvey Johnson 2398 Oaklyn St NE Palm Bay, FL 32907 - or - QUILL BBS 305-724-2303 Future Products It would be nice to have a version of ARC written to utilize GEM. I would also like to write a picture display feature that will show compressed pictures directly to the screen. This will be useful in that ARC squeezes file 5 to 10% smaller than TINY format. If anyone has the C source to dump NEO, Degas, or other pictures to the screen please upload a copy to QUILL BBS. It would also be nice to allow file redirection from Micro C-Shell; however, this is not possible because Micro C-Shell and Megamax C are not compatible at this time. If you have any ideas for additional capabilities, then send them to me with a detailed explanation. All thoughts are welcome. Donations It would be nice to be supported if you think that ARC is any good. Make no mistake, I did NOT write the original version of ARC, but I have spent all my extra time for two months making it a reality on the Atari ST. As I do recieve contributions, I will consider improvements more seriously. Any donations may be sent to address specified in Bug Report section. Thank you one and all in advance for considering this request, but if you are like me (lazy) then I don't really expect to ever see a single dime. ARCHIVE (ARC.TTP) Usage arc {amufdxerplvtc}[bswnh][g<password>] <archive> [<filname> ...] a = add files to archive m = move files to archive u = update files in archive f = freshen files in archive d = delete files in archive x,e = extract files from archive r = run one file with arguments from archive p = copy files from archive to standard output l = list files in archive v = verbose listing of files in archive t = test archive integrity c = convert entry to new packing method b = retain backup copy of archive s = suppress compression (use Method 2) w = suppress warning messages n = suppress notes and comments h = hold screen before returning to Desktop g = encrypt/decrypt archive entry Description This program is a general archive utility, and is used to maintain an archive of files. An "archive" is a single file that combines many files, reducing storage space and allowing multiple files to be handled as one. Switches a - add files to archive. This switch will force update or addition the indicated reguardless of creation time and date. m - move files to archive. Same as "a" switch except that the files are deleted from the directory as they are moved to the archive. u - update files in archive. This switch will only update files when the creation date is newer than the corresponding file in the archive. New files will be added automatically. f - freshen files in archive. Same as "u" except that new files will not be added. d - delete files in archive. The files are lost forever and the archive is recompacted to remove the data for these files. x,e - extract files from archive. A copy of the files in the archive are created in the current directory in an uncompacted state. r - run one file with arguments from archive. Any program (.TTP, .TOS, or .PRG) may be executed directly from the archive. If the program has a resource (.RSC) it must have the same name as the program (ex: editor.RSC for editor.PRG). The parameters after the program name are passed to the program without modification (doubleqotes may be necessary). p - copy files from archive to standard output. Useful for viewing test files in an archive. May also be handy when used with I/O redirection in C-shells. l - list files in archive. Limited information listing of files contained in an archive. Displays only the filename. v - verbose listing of files in archive. Complete information listing of files contained in an archive. Displays the filename, original length, storage method, storage factor (% savings), compacted size, date, time, and CRC. t - test archive integrity. Check the archive to make sure it does not have any bad files contained. c - convert entry to new packing method. Convert files stored with older methods to newer methods that are more efficient. b - retain backup copy of archive. Keep the original archive file and rename to .BAK. The new version is named .ARC. This switch may be used with the following switches: a, m, u, f, d, c. s - suppress compression. This forces new files to be saved using Method 2 (no compaction). This switch may be used with the following switches: a, m, u, f, c. w - suppress warning messages. This switch will keep warning message from being displayed which is the default. Most warnings concern the deletion or existence of files with the same name. n - suppress notes and comments. This switch will keep useful notes from being diaplyed which is the default. Most notes indicate what stage of compaction is being run (analyze, compaction, storage). h - hold screen before returning to Desktop. This switch should be used whenever ARC is executed from the Desktop, except in conjunction with file redirection. g - encrypt/decrypt archive entry. This is used encode files so that others may not read them. BE CAREFUL! This must be the last parameter in the switches because everything following is part of the password. Examples Micro C-Shell users should remember to use quotes with each template in the following examples to prevent expansion by the shell, see examples. % arc will show usage instructions % arc v old.arc will show detailed listing of files stored in an archive % arc v old same as previous example because .ARC is assumed % arc x old will extract all files % arc x old *.c will extract all .C files % arc x old "*.c" same as previous example % arc p old file.doc will print a file to screen % arc u old *.c will update or insert the .C files in current directory % arc ub old "*.c" same as above except old archive is renamed OLD.BAK % arc ugHIDE diary dec86.txt will update diary.arc with dec86.txt that is encrypt with the key "HIDE" % arc xgHIDE diary dec86.txt will extract dec86.txt from diary.arc and decrypt with the key "HIDE" % arc r util.arc editor text.doc will run the program editor (.TTP, .TOS or .PRG) and pass text.doc as an argument File redirection is available when executing ARC from the Desktop (Micro C-Shell apparently has a hidden defect which prevents this capability). In order to redirect the output, just add >FILENAME to the end of any example above where FILENAME is the name of the file to recieve the output which normally is displayed on the screen. ARCHIVE MERGE (ARCM.TTP) Usage arcm <tgtarc> <srcarc> [<filename> ...] <tgtarc> is the archive to add files to <srcarc> is the archive to get files from <filename> is the specific files to get from <srcarc>, *.* is assumed Description This program is used to merge archives. That is, to move files from one archive to another with no data conversion necessary. Notice you may only merge two archives at a time. Examples Micro C-Shell users should remember to use quotes with each template in the following examples to prevent expansion by the shell, see last example. % arcm will show usage instructions % arcm put.arc get.arc will add all files from get.arc to put.arc % arcm put get same as previous example because .ARC is assumed % arcm put get *.c will add only .C files from get.arc to put.arc % arcm put get "*.c" same as previous example ARCHIVE EXTRACT (ARCX.TTP) Usage arcx <arcname> [<arcname> ...] Description This program is used to extract files from multiple archives creates using the ARC general maintenance program. It is similar to ARC X except that it allows the user to specify many archive libraries or use an archive filename template. This utility will extract all files from each archive indicated. Examples % arcx will show usage instructions % arcx arc.arc will extract files from the archive named "arc.arc" % arcx arc same as previous example because .ARC is assumed % arcx one.arc two will extract files from the two specified archives only % arcx *.arc will extract files from all archives in current directory TECHNICAL Library Format All files are stored in alphabetical order in the archive library. The final .ARC library should have a time of modification which is the same as the most recently modified (youngest) file in the library. When each file is extracted its time and date are set to that which is stored in the header (see next paragraph). Each entry in the library has a header which contains the following information: Filename 13 bytes (char) Size 4 (long) Date 2 (int) Time 2 (int) CRC 2 (int) Length 4 (long) The filename is always followed by a zero (NUL) character. All of the "int" and "long" feilds are stored in reverse order, least significant bytes first and most significant bytes last. The date and time use are specified in standard format (same as that used on IBM and Atari ST). Compression Routines Method 1 - no conversion - files stored using this method are not translated. This method has been eliminated in favor of method two which also stores the original file length. Appears as "--" in verbose listing. Method 2 - no conversion - files stored using this method are not translated. Appears as "--" in verbose listing. Method 3 - repeat character compression - files stored using this method convert strings of letters to that letter followed a count. "AAAAA" becomes "A5" in simple terms. Appears as "Packed" in verbose listing. Method 4 - Huffman squeezing - files stored using this method convert characters to smaller bit strings depending on frequency count of appearance in file. Appears as "Squeezed" in verbose listing. Method 5,6,7 - Lempel-Zev compression - files stored in any of these methods take advantage of repeated strings of non-identical characters that appear repeatedly through the file as well as a hashing function. Various additional improvements distinguish this methods from each other. Appears as "crunched" in verbose listing. Method 8 - Dynamic Lempel-Zev - files stored using this method takes advantage of repeated strings of non-identical characters that appear repeatedly throughout the file. These is by far the most efficient and commonly employed method of compression. Appears as "Crunched" in verbose listing. Other Methods - unknown methods - files stored using more advanced techniques may appear in the future. The current version of ARC will not be able to retreive this files. Appears as "Unknown!" in verbose listing.