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GNU 系统开发的基于Iz77语法的压缩 学习lz77压缩算法

Current Version: 1.0.7
See the file ChangeLog for the details of all changes.

User visible changes from 1.0.6 to 1.0.7.

o Allow zmore to read from standard input (like more).

o Support the 68000 (Atari ST) in match.S.

o Retry partial writes (required on Linux when gzip is suspended in a pipe).

o Allow full pathnames and renamings in gzexe.
  Don't let gzexe compress setuid executables or gzip itself.
	
o Added vms/Makefile.gcc for gcc on the Vax.

o Allow installation of binaries and shell scripts in different dirs.

o Allows complex PAGER variable in zmore (e.g.: PAGER="col -x | more")

o Allow installation of zcat as gzcat.

o Several small changes for portability to old or weird systems.

o Suppress help message and send compressed data to the terminal when
  gzip is invoked without parameters and without redirection.

o  Add compile option GNU_STANDARD to respect the GNU coding standards:
   with -DGNU_STANDARD, behave as gzip even if invoked under the name gunzip.

(I don't like the last two changes, which were requested by the FSF.)


User visible changes from 1.0.5 to 1.0.6.

o Let gzexe detect executables that are already gzexe'd.

o Keep file attributes in znew and gzexe if cpmod is available.

o Don't try restoring record format on VMS (1.0.5 did not work correctly)

o Added asm version for 68000 in amiga/match.a.
  Use asm version for Atari TT and NeXT.

o For OS/2, assume HPFS by default, add flag OS2FAT if necessary.

o Fixed some bugs in zdiff and define zcmp as a link to zdiff.


User visible changes from 1.0.4 to 1.0.5.

o For VMS, restore the file type for variable record format, otherwise
    extract in fixed length format (not perfect, but better than
    forcing all files to be in stream_LF format).

o For VMS, use "-z" default suffix and accept a version number in file names.

o For Unix, allow compression of files with name ending in 'z'. Use only
  .z, .*-z, .tgz, .taz as valid gzip extensions. In the last two cases,
  extract to .tar by default.

o On some versions of MSDOS, files with a 3 character extension could not
  be compressed.

o Garbage collect files in /tmp created by gzexe.

o Fix the 'OS code' byte in the gzip header.

o For the Amiga, add the missing utime.h and add support for gcc.


User visible changes from 1.0.3 to 1.0.4.

o Added optimized asm version for 68020.

o Add support for DJGPP.
	
o Add support for the Atari ST.

o Added zforce to rename gzip'ed files with truncated names.

o Do not install with name uncompress (some systems rely on the
  absence of any check in the old uncompress).

o Added missing function (fcfree) in msdos/tailor.c

o Let gunzip handle .tgz files, and let gzip skip them.

o Added -d option (decompress) for gzexe and try preserving file permissions.

o Suppress all warnings with -q.

o Use GZIP_OPT for VMS to avoid conflict with program name.

o ... and many other small changes (see ChangeLog)


User visible changes from 1.0.2 to 1.0.3

o Added -K option for znew to keep old .Z files if smaller

o Added -q option (quiet) to cancel -v in GZIP env variable.

o Made gzexe safer on systems with filename limitation to 14 chars.

o Fixed bugs in handling of GZIP env variable and incorrect free with Turbo C.


User visible changes from 1.0.1 to 1.0.2

o Added env variable GZIP for default options. Example:
   for sh:   GZIP="-8 -v"; export GZIP
   for csh:  setenv GZIP "-8 -v"

o Added support for the Amiga.

O znew now keeps the old .Z if it is smaller than the .z file.
  This can happen for some large and very redundant files.

o Do not complain about trailing garbage for record oriented IO (Vax/VMS).
  This implies however that multi-part gzip files are not supported
  on such systems.

o Added gzexe to compress rarely used executables.

o Reduce memory usage (required for MSDOS and useful on all systems).

o Preserve time stamp in znew -P (pipe option) if touch -r works.


User visible changes from 1.0 to 1.0.1

o fix trivial errors in the Borland makefile (msdos/Makefile.bor)


User visible changes from 0.8.2 to 1.0

o gzip now runs on Vax/VMS

o gzip will not not overwrite files without -f when using /bin/sh in
  background.

o Support the test option -t for compressed (.Z) files.
  Allow some data recovery for bad .Z files.

o Added makefiles for MSDOS (Only tested for MSC, not Borland).

o still more changes to configure for several systems


User visible changes from 0.8.1 to 0.8.2:

o yet more changes to configure for Linux and other systems

o Allow zcat on a file with multiple links.


User visible changes from 0.8 to 0.8.1:

o znew has now a pipe option -P to reduce the disk space requirements,
  but this option does not preserve timestamps.

o Fixed some #if directives for compilation with TurboC.


User visible changes from 0.7 to 0.8:

o gzip can now extract .z files created by 'pack'.

o configure should no longer believe that every machine is a 386

o Fix the entry for /etc/magic in INSTALL.

o Add patch for GNU tar 1.11.1 and a pointer to crypt++.el

o Uncompress files with multiple links only with -f.

o Fix for uncompress of .Z files on 16-bit machines

o Create a correct output name for file names of exactly N-1 chars when
  the system has a limit of N chars.


User visible changes from 0.6 to 0.7:

o Use "make check" instead of "make test".

o Keep time stamp and pass options to gzip in znew.

o Do not create .z.z files with gzip -r.

o Allow again gunzip .zip files (was working in 0.5)

o Allow again compilation with TurboC 2.0 (was working in 0.4)


User visible changes form 0.5 to 0.6:

o gunzip reported an error when extracting certain .z files. The .z files
  produced by gzip 0.5 are correct and can be read by gunzip 0.6.

o gunzip now supports multiple compressed members within a single .z file.

o Fix the check for i386 in configure.

o Added "make test" to check for compiler bugs. (gcc -finline-functions
  is broken at least on the NeXT.)

o Use environment variable PAGER in zmore if it is defined.

o Accept gzcat in addition to zcat for people having /usr/bin before
  /usr/local/bin in their path.