readme

给出了 zip 压缩算法的完整实现过程。

Tandem Port of Info ZIP (zip)
=======================

History:
1. Tidy up COMMACS/MACROS/MAKE
2. Changes for version 5.32d affected files:
- TANDEMC     (changes to stat() for UNZIP)
- ZIPUPC      (changes to use REVISIOH rather than REVISEH)
- ZIPFILEC    (don't add ".zip" to ZIP name)
- FILEIOC     (cosmetic missing "*/")
3. Fix to allow zipping of files called ZIP (e.g. DAVES.ZIP)
03/08/98  2.3e   Process Tandem DEFINE names - use define name as internal name
                 Remove BITSO from build of ZIPLIB
                 New DOIT macro for extracting files from archive
17/08/98  2.3e   Set USE_EF_UT_TIME to allow for timezone changes
18/08/98  2.3e   Use define LICENSED to build object able to update timestamps
30/11/98  2.3h   Updated mapname/chmod/in2ex, include licensing in MAKE
21/12/98  2.3i   Add simple Enscribe file handling, consisting of:
                 - storing Enscribe files as LF delimited text files
                 - adding Tandem Extra Field, holding Enscribe file attributes
                 Create ZIP file with Tandem File Code 1001
                 Rationalised TANDEMH and TANDEMC wth UNZIP 5.40d
12/01/99  2.3i   Correct bug stopping setting of last open timestamp
25/01/99  2.3k   Add '-B' flag to zip Enscribe files with no record delimiters
26/01/99  2.3k   Make CRLF the default delimiter for Structured and Text files
01/02/99  2.3k   Use maximum size large transfer read (57344) as default, allow
                 smaller value as option
01/02/99  2.3k   Redefine -B flag for Edit/Enscribe files as in table below.
                 Default (-B or -B0 or no flag) is add CR/LF

                 -B<number> options at present are:
                 Bit 0 -  Don't add delimiter (Edit/Enscribe)
                 Bit 1 -  Use LF rather than CR/LF as delimiter (Edit/Enscribe)
                 Bit 2 -  Space fill record to max record length (Enscribe)
                 Bit 3 -  Trim trailing space (Edit/Enscribe)

                 Bit 8 -  Force 30K (Expand) large read for Unstructured files

06/02/99  2.3k   Attempt to catch Large Transfer mode failure (err 21) when
                 attempting 56K reads, add substitute 30K reads (Expand files)
24/03/99  2.3m   Split TANDEMC into TANDEMC/TANZIPC/TANUNZC
24/03/99  2.3m   Added TANNSKH to allow for declarations which require
                 structures defined in ZIPH after call to TANDEMH
11/05/99  2.3m   Change zopen in TANZIPC to allow opening of files with
                 missing alt keys (err 4)
                 Assume not DST if can't resolve time (no DST table available)
27/09/99  2.3o   Fixed bug in -B0 option causing files to be stored rather than
                 deflated. Created TANZIPH

A few notes about the files on this subvol

COMMACS   -  used by MAKE (compiler)
DOIT      -  macro to extract required Tandem files from archive and rename
MACROS    -  used by MAKE (bind)
MAKE      -  recompile ZIP code, attempts to only recompile changed code
README    -  this file
ZIPLIB    -  library of ZIP compiled routines, used by ZIP/ZIPNOTE etc
ZIPL      -  ZIP object (bound using LARGE memory model)
ZIPNOTE   -  ZIPNOTE object (bound using LARGE memory model)

*C        -  Source file
*H        -  Header files
*O        -  Individual object files (when compiled by MAKE)

Install Notes:
==============
Stage 1 - get ZIP object onto Tandem
- download Tandem Zip executables archive from Web
- using PC unzip program (e.g. pkunzip/WinZip) extract ZIP
- copy ZIP from PC to Tandem in Binary mode s(FTP/IXF)
- alter file code to 100
- optionally place in $SYSTEM.SYSTEM to allow easy access from command line

Stage 2 - (optional) compile source code (requires UNZIP on Tandem)
- download ZIP source archive fwom web - contains all supported platforms
- copy archive onto Tandem as Binary
- extract Tandem DOIT macro ( UNZIP -j <archive> tandem/DOIT )
- update DOIT macro to point at archive file
- restore relevant files by running DOIT
- NOTE that revision.h must be restored as REVISIOH
- replace references to $T with a collector on your system
- replace references to SUPER.DAVES with whatever user id you use
- to compile run MAKE (compiles, accelerates, licences)
- NOTE:  Always run the accelerated object on TNS/R systems, otherwise
         it runs extremely slow.


Additional Notes - LICENSE the object:
======================================
If you wish to be able to update the last modified time of the zip file
(-o option) you need to add the line "#define LICENSED" to the TANDEMH file.
If you set this option then you MUST FUP LICENSE the file as SUPER.SUPER.
This is a Tandem restriction since we have to call a PRIV procedure to update
the file label.  For ZIP the define is setup (default) in tandem.h