_gzip.py 文件源码

def compress_readable_output(src_file, compress_level=6):
    crc = zlib.crc32(b"")
    size = 0
    zobj = zlib.compressobj(compress_level, zlib.DEFLATED, -zlib.MAX_WBITS,
                            zlib.DEF_MEM_LEVEL, zlib.Z_DEFAULT_STRATEGY)
    prefix_written = False
    while True:
        data = src_file.read(DEFAULT_BUFFER_SIZE)
        if not data:
            break
        size += len(data)
        crc = zlib.crc32(data, crc)
        data = zobj.compress(data)
        if not prefix_written:
            prefix_written = True
            data = gzip_prefix() + data
        yield data
    yield zobj.flush() + struct.pack(b"<LL", crc & 0xffffffffL, size)