diff options
author | Ori Bernstein <ori@eigenstate.org> | 2021-06-14 00:00:37 +0000 |
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committer | Ori Bernstein <ori@eigenstate.org> | 2021-06-14 00:00:37 +0000 |
commit | a73a964e51247ed169d322c725a3a18859f109a3 (patch) | |
tree | 3f752d117274d444bda44e85609aeac1acf313f3 /sys/src/cmd/python/Demo/zlib/minigzip.py | |
parent | e64efe273fcb921a61bf27d33b230c4e64fcd425 (diff) |
python, hg: tow outside the environment.
they've served us well, and can ride off into the sunset.
Diffstat (limited to 'sys/src/cmd/python/Demo/zlib/minigzip.py')
-rwxr-xr-x | sys/src/cmd/python/Demo/zlib/minigzip.py | 133 |
1 files changed, 0 insertions, 133 deletions
diff --git a/sys/src/cmd/python/Demo/zlib/minigzip.py b/sys/src/cmd/python/Demo/zlib/minigzip.py deleted file mode 100755 index 87fed4ae5..000000000 --- a/sys/src/cmd/python/Demo/zlib/minigzip.py +++ /dev/null @@ -1,133 +0,0 @@ -#!/usr/bin/env python -# Demo program for zlib; it compresses or decompresses files, but *doesn't* -# delete the original. This doesn't support all of gzip's options. -# -# The 'gzip' module in the standard library provides a more complete -# implementation of gzip-format files. - -import zlib, sys, os - -FTEXT, FHCRC, FEXTRA, FNAME, FCOMMENT = 1, 2, 4, 8, 16 - -def write32(output, value): - output.write(chr(value & 255)) ; value=value // 256 - output.write(chr(value & 255)) ; value=value // 256 - output.write(chr(value & 255)) ; value=value // 256 - output.write(chr(value & 255)) - -def read32(input): - v = ord(input.read(1)) - v += (ord(input.read(1)) << 8 ) - v += (ord(input.read(1)) << 16) - v += (ord(input.read(1)) << 24) - return v - -def compress (filename, input, output): - output.write('\037\213\010') # Write the header, ... - output.write(chr(FNAME)) # ... flag byte ... - - statval = os.stat(filename) # ... modification time ... - mtime = statval[8] - write32(output, mtime) - output.write('\002') # ... slowest compression alg. ... - output.write('\377') # ... OS (=unknown) ... - output.write(filename+'\000') # ... original filename ... - - crcval = zlib.crc32("") - compobj = zlib.compressobj(9, zlib.DEFLATED, -zlib.MAX_WBITS, - zlib.DEF_MEM_LEVEL, 0) - while True: - data = input.read(1024) - if data == "": - break - crcval = zlib.crc32(data, crcval) - output.write(compobj.compress(data)) - output.write(compobj.flush()) - write32(output, crcval) # ... the CRC ... - write32(output, statval[6]) # and the file size. - -def decompress (input, output): - magic = input.read(2) - if magic != '\037\213': - print 'Not a gzipped file' - sys.exit(0) - if ord(input.read(1)) != 8: - print 'Unknown compression method' - sys.exit(0) - flag = ord(input.read(1)) - input.read(4+1+1) # Discard modification time, - # extra flags, and OS byte. - if flag & FEXTRA: - # Read & discard the extra field, if present - xlen = ord(input.read(1)) - xlen += 256*ord(input.read(1)) - input.read(xlen) - if flag & FNAME: - # Read and discard a null-terminated string containing the filename - while True: - s = input.read(1) - if s == '\0': break - if flag & FCOMMENT: - # Read and discard a null-terminated string containing a comment - while True: - s=input.read(1) - if s=='\0': break - if flag & FHCRC: - input.read(2) # Read & discard the 16-bit header CRC - - decompobj = zlib.decompressobj(-zlib.MAX_WBITS) - crcval = zlib.crc32("") - length = 0 - while True: - data=input.read(1024) - if data == "": - break - decompdata = decompobj.decompress(data) - output.write(decompdata) - length += len(decompdata) - crcval = zlib.crc32(decompdata, crcval) - - decompdata = decompobj.flush() - output.write(decompdata) - length += len(decompdata) - crcval = zlib.crc32(decompdata, crcval) - - # We've read to the end of the file, so we have to rewind in order - # to reread the 8 bytes containing the CRC and the file size. The - # decompressor is smart and knows when to stop, so feeding it - # extra data is harmless. - input.seek(-8, 2) - crc32 = read32(input) - isize = read32(input) - if crc32 != crcval: - print 'CRC check failed.' - if isize != length: - print 'Incorrect length of data produced' - -def main(): - if len(sys.argv)!=2: - print 'Usage: minigzip.py <filename>' - print ' The file will be compressed or decompressed.' - sys.exit(0) - - filename = sys.argv[1] - if filename.endswith('.gz'): - compressing = False - outputname = filename[:-3] - else: - compressing = True - outputname = filename + '.gz' - - input = open(filename, 'rb') - output = open(outputname, 'wb') - - if compressing: - compress(filename, input, output) - else: - decompress(input, output) - - input.close() - output.close() - -if __name__ == '__main__': - main() |