/brz/remove-bazaar

To get this branch, use:
bzr branch http://gegoxaren.bato24.eu/bzr/brz/remove-bazaar

« back to all changes in this revision

Viewing changes to bzrlib/tuned_gzip.py

  • Committer: John Arbash Meinel
  • Date: 2009-06-04 17:12:29 UTC
  • mto: This revision was merged to the branch mainline in revision 4410.
  • Revision ID: john@arbash-meinel.com-20090604171229-kbgfatt63y3u3uh1
Some small tweaks to decoding strings (avoid passing over the length 2x)

Down to 1.1s (from 1.4s) for decoding all of bzr.dev.
Also, favor decoding strings and then lists in _decode_object, since that is the
frequency we have those types inside Revisions.

Show diffs side-by-side

added added

removed removed

Lines of Context:
bzrlib/tuned_gzip.py
52
52
    width=-zlib.MAX_WBITS, mem=zlib.DEF_MEM_LEVEL,
53
53
    crc32=zlib.crc32):
54
54
    """Create a gzip file containing bytes and return its content."""
55
 
    return chunks_to_gzip([bytes])
56
 
 
57
 
 
58
 
def chunks_to_gzip(chunks, factory=zlib.compressobj,
59
 
    level=zlib.Z_DEFAULT_COMPRESSION, method=zlib.DEFLATED,
60
 
    width=-zlib.MAX_WBITS, mem=zlib.DEF_MEM_LEVEL,
61
 
    crc32=zlib.crc32):
62
 
    """Create a gzip file containing chunks and return its content.
63
 
 
64
 
    :param chunks: An iterable of strings. Each string can have arbitrary
65
 
        layout.
66
 
    """
67
55
    result = [
68
56
        '\037\213'  # self.fileobj.write('\037\213')  # magic header
69
57
        '\010'      # self.fileobj.write('\010')      # compression method
81
69
    # using a compressobj avoids a small header and trailer that the compress()
82
70
    # utility function adds.
83
71
    compress = factory(level, method, width, mem, 0)
84
 
    crc = 0
85
 
    total_len = 0
86
 
    for chunk in chunks:
87
 
        crc = crc32(chunk, crc)
88
 
        total_len += len(chunk)
89
 
        zbytes = compress.compress(chunk)
90
 
        if zbytes:
91
 
            result.append(zbytes)
 
72
    result.append(compress.compress(bytes))
92
73
    result.append(compress.flush())
 
74
    result.append(struct.pack("<L", LOWU32(crc32(bytes))))
93
75
    # size may exceed 2GB, or even 4GB
94
 
    result.append(struct.pack("<LL", LOWU32(crc), LOWU32(total_len)))
 
76
    result.append(struct.pack("<L", LOWU32(len(bytes))))
95
77
    return ''.join(result)
96
78
 
97
79