| 1 | """Functions that read and write gzipped files.
|
|---|
| 2 |
|
|---|
| 3 | The user of the file doesn't have to worry about the compression,
|
|---|
| 4 | but random access is not allowed."""
|
|---|
| 5 |
|
|---|
| 6 | # based on Andrew Kuchling's minigzip.py distributed with the zlib module
|
|---|
| 7 |
|
|---|
| 8 | import struct, sys, time, os
|
|---|
| 9 | import zlib
|
|---|
| 10 | import io
|
|---|
| 11 | import __builtin__
|
|---|
| 12 |
|
|---|
| 13 | __all__ = ["GzipFile","open"]
|
|---|
| 14 |
|
|---|
| 15 | FTEXT, FHCRC, FEXTRA, FNAME, FCOMMENT = 1, 2, 4, 8, 16
|
|---|
| 16 |
|
|---|
| 17 | READ, WRITE = 1, 2
|
|---|
| 18 |
|
|---|
| 19 | def write32u(output, value):
|
|---|
| 20 | # The L format writes the bit pattern correctly whether signed
|
|---|
| 21 | # or unsigned.
|
|---|
| 22 | output.write(struct.pack("<L", value))
|
|---|
| 23 |
|
|---|
| 24 | def read32(input):
|
|---|
| 25 | return struct.unpack("<I", input.read(4))[0]
|
|---|
| 26 |
|
|---|
| 27 | def open(filename, mode="rb", compresslevel=9):
|
|---|
| 28 | """Shorthand for GzipFile(filename, mode, compresslevel).
|
|---|
| 29 |
|
|---|
| 30 | The filename argument is required; mode defaults to 'rb'
|
|---|
| 31 | and compresslevel defaults to 9.
|
|---|
| 32 |
|
|---|
| 33 | """
|
|---|
| 34 | return GzipFile(filename, mode, compresslevel)
|
|---|
| 35 |
|
|---|
| 36 | class GzipFile(io.BufferedIOBase):
|
|---|
| 37 | """The GzipFile class simulates most of the methods of a file object with
|
|---|
| 38 | the exception of the readinto() and truncate() methods.
|
|---|
| 39 |
|
|---|
| 40 | """
|
|---|
| 41 |
|
|---|
| 42 | myfileobj = None
|
|---|
| 43 | max_read_chunk = 10 * 1024 * 1024 # 10Mb
|
|---|
| 44 |
|
|---|
| 45 | def __init__(self, filename=None, mode=None,
|
|---|
| 46 | compresslevel=9, fileobj=None, mtime=None):
|
|---|
| 47 | """Constructor for the GzipFile class.
|
|---|
| 48 |
|
|---|
| 49 | At least one of fileobj and filename must be given a
|
|---|
| 50 | non-trivial value.
|
|---|
| 51 |
|
|---|
| 52 | The new class instance is based on fileobj, which can be a regular
|
|---|
| 53 | file, a StringIO object, or any other object which simulates a file.
|
|---|
| 54 | It defaults to None, in which case filename is opened to provide
|
|---|
| 55 | a file object.
|
|---|
| 56 |
|
|---|
| 57 | When fileobj is not None, the filename argument is only used to be
|
|---|
| 58 | included in the gzip file header, which may includes the original
|
|---|
| 59 | filename of the uncompressed file. It defaults to the filename of
|
|---|
| 60 | fileobj, if discernible; otherwise, it defaults to the empty string,
|
|---|
| 61 | and in this case the original filename is not included in the header.
|
|---|
| 62 |
|
|---|
| 63 | The mode argument can be any of 'r', 'rb', 'a', 'ab', 'w', or 'wb',
|
|---|
| 64 | depending on whether the file will be read or written. The default
|
|---|
| 65 | is the mode of fileobj if discernible; otherwise, the default is 'rb'.
|
|---|
| 66 | Be aware that only the 'rb', 'ab', and 'wb' values should be used
|
|---|
| 67 | for cross-platform portability.
|
|---|
| 68 |
|
|---|
| 69 | The compresslevel argument is an integer from 0 to 9 controlling the
|
|---|
| 70 | level of compression; 1 is fastest and produces the least compression,
|
|---|
| 71 | and 9 is slowest and produces the most compression. 0 is no compression
|
|---|
| 72 | at all. The default is 9.
|
|---|
| 73 |
|
|---|
| 74 | The mtime argument is an optional numeric timestamp to be written
|
|---|
| 75 | to the stream when compressing. All gzip compressed streams
|
|---|
| 76 | are required to contain a timestamp. If omitted or None, the
|
|---|
| 77 | current time is used. This module ignores the timestamp when
|
|---|
| 78 | decompressing; however, some programs, such as gunzip, make use
|
|---|
| 79 | of it. The format of the timestamp is the same as that of the
|
|---|
| 80 | return value of time.time() and of the st_mtime member of the
|
|---|
| 81 | object returned by os.stat().
|
|---|
| 82 |
|
|---|
| 83 | """
|
|---|
| 84 |
|
|---|
| 85 | # Make sure we don't inadvertently enable universal newlines on the
|
|---|
| 86 | # underlying file object - in read mode, this causes data corruption.
|
|---|
| 87 | if mode:
|
|---|
| 88 | mode = mode.replace('U', '')
|
|---|
| 89 | # guarantee the file is opened in binary mode on platforms
|
|---|
| 90 | # that care about that sort of thing
|
|---|
| 91 | if mode and 'b' not in mode:
|
|---|
| 92 | mode += 'b'
|
|---|
| 93 | if fileobj is None:
|
|---|
| 94 | fileobj = self.myfileobj = __builtin__.open(filename, mode or 'rb')
|
|---|
| 95 | if filename is None:
|
|---|
| 96 | # Issue #13781: os.fdopen() creates a fileobj with a bogus name
|
|---|
| 97 | # attribute. Avoid saving this in the gzip header's filename field.
|
|---|
| 98 | if hasattr(fileobj, 'name') and fileobj.name != '<fdopen>':
|
|---|
| 99 | filename = fileobj.name
|
|---|
| 100 | else:
|
|---|
| 101 | filename = ''
|
|---|
| 102 | if mode is None:
|
|---|
| 103 | if hasattr(fileobj, 'mode'): mode = fileobj.mode
|
|---|
| 104 | else: mode = 'rb'
|
|---|
| 105 |
|
|---|
| 106 | if mode[0:1] == 'r':
|
|---|
| 107 | self.mode = READ
|
|---|
| 108 | # Set flag indicating start of a new member
|
|---|
| 109 | self._new_member = True
|
|---|
| 110 | # Buffer data read from gzip file. extrastart is offset in
|
|---|
| 111 | # stream where buffer starts. extrasize is number of
|
|---|
| 112 | # bytes remaining in buffer from current stream position.
|
|---|
| 113 | self.extrabuf = ""
|
|---|
| 114 | self.extrasize = 0
|
|---|
| 115 | self.extrastart = 0
|
|---|
| 116 | self.name = filename
|
|---|
| 117 | # Starts small, scales exponentially
|
|---|
| 118 | self.min_readsize = 100
|
|---|
| 119 |
|
|---|
| 120 | elif mode[0:1] == 'w' or mode[0:1] == 'a':
|
|---|
| 121 | self.mode = WRITE
|
|---|
| 122 | self._init_write(filename)
|
|---|
| 123 | self.compress = zlib.compressobj(compresslevel,
|
|---|
| 124 | zlib.DEFLATED,
|
|---|
| 125 | -zlib.MAX_WBITS,
|
|---|
| 126 | zlib.DEF_MEM_LEVEL,
|
|---|
| 127 | 0)
|
|---|
| 128 | else:
|
|---|
| 129 | raise IOError, "Mode " + mode + " not supported"
|
|---|
| 130 |
|
|---|
| 131 | self.fileobj = fileobj
|
|---|
| 132 | self.offset = 0
|
|---|
| 133 | self.mtime = mtime
|
|---|
| 134 |
|
|---|
| 135 | if self.mode == WRITE:
|
|---|
| 136 | self._write_gzip_header()
|
|---|
| 137 |
|
|---|
| 138 | @property
|
|---|
| 139 | def filename(self):
|
|---|
| 140 | import warnings
|
|---|
| 141 | warnings.warn("use the name attribute", DeprecationWarning, 2)
|
|---|
| 142 | if self.mode == WRITE and self.name[-3:] != ".gz":
|
|---|
| 143 | return self.name + ".gz"
|
|---|
| 144 | return self.name
|
|---|
| 145 |
|
|---|
| 146 | def __repr__(self):
|
|---|
| 147 | s = repr(self.fileobj)
|
|---|
| 148 | return '<gzip ' + s[1:-1] + ' ' + hex(id(self)) + '>'
|
|---|
| 149 |
|
|---|
| 150 | def _check_closed(self):
|
|---|
| 151 | """Raises a ValueError if the underlying file object has been closed.
|
|---|
| 152 |
|
|---|
| 153 | """
|
|---|
| 154 | if self.closed:
|
|---|
| 155 | raise ValueError('I/O operation on closed file.')
|
|---|
| 156 |
|
|---|
| 157 | def _init_write(self, filename):
|
|---|
| 158 | self.name = filename
|
|---|
| 159 | self.crc = zlib.crc32("") & 0xffffffffL
|
|---|
| 160 | self.size = 0
|
|---|
| 161 | self.writebuf = []
|
|---|
| 162 | self.bufsize = 0
|
|---|
| 163 |
|
|---|
| 164 | def _write_gzip_header(self):
|
|---|
| 165 | self.fileobj.write('\037\213') # magic header
|
|---|
| 166 | self.fileobj.write('\010') # compression method
|
|---|
| 167 | fname = os.path.basename(self.name)
|
|---|
| 168 | if fname.endswith(".gz"):
|
|---|
| 169 | fname = fname[:-3]
|
|---|
| 170 | flags = 0
|
|---|
| 171 | if fname:
|
|---|
| 172 | flags = FNAME
|
|---|
| 173 | self.fileobj.write(chr(flags))
|
|---|
| 174 | mtime = self.mtime
|
|---|
| 175 | if mtime is None:
|
|---|
| 176 | mtime = time.time()
|
|---|
| 177 | write32u(self.fileobj, long(mtime))
|
|---|
| 178 | self.fileobj.write('\002')
|
|---|
| 179 | self.fileobj.write('\377')
|
|---|
| 180 | if fname:
|
|---|
| 181 | self.fileobj.write(fname + '\000')
|
|---|
| 182 |
|
|---|
| 183 | def _init_read(self):
|
|---|
| 184 | self.crc = zlib.crc32("") & 0xffffffffL
|
|---|
| 185 | self.size = 0
|
|---|
| 186 |
|
|---|
| 187 | def _read_gzip_header(self):
|
|---|
| 188 | magic = self.fileobj.read(2)
|
|---|
| 189 | if magic != '\037\213':
|
|---|
| 190 | raise IOError, 'Not a gzipped file'
|
|---|
| 191 | method = ord( self.fileobj.read(1) )
|
|---|
| 192 | if method != 8:
|
|---|
| 193 | raise IOError, 'Unknown compression method'
|
|---|
| 194 | flag = ord( self.fileobj.read(1) )
|
|---|
| 195 | self.mtime = read32(self.fileobj)
|
|---|
| 196 | # extraflag = self.fileobj.read(1)
|
|---|
| 197 | # os = self.fileobj.read(1)
|
|---|
| 198 | self.fileobj.read(2)
|
|---|
| 199 |
|
|---|
| 200 | if flag & FEXTRA:
|
|---|
| 201 | # Read & discard the extra field, if present
|
|---|
| 202 | xlen = ord(self.fileobj.read(1))
|
|---|
| 203 | xlen = xlen + 256*ord(self.fileobj.read(1))
|
|---|
| 204 | self.fileobj.read(xlen)
|
|---|
| 205 | if flag & FNAME:
|
|---|
| 206 | # Read and discard a null-terminated string containing the filename
|
|---|
| 207 | while True:
|
|---|
| 208 | s = self.fileobj.read(1)
|
|---|
| 209 | if not s or s=='\000':
|
|---|
| 210 | break
|
|---|
| 211 | if flag & FCOMMENT:
|
|---|
| 212 | # Read and discard a null-terminated string containing a comment
|
|---|
| 213 | while True:
|
|---|
| 214 | s = self.fileobj.read(1)
|
|---|
| 215 | if not s or s=='\000':
|
|---|
| 216 | break
|
|---|
| 217 | if flag & FHCRC:
|
|---|
| 218 | self.fileobj.read(2) # Read & discard the 16-bit header CRC
|
|---|
| 219 |
|
|---|
| 220 | def write(self,data):
|
|---|
| 221 | self._check_closed()
|
|---|
| 222 | if self.mode != WRITE:
|
|---|
| 223 | import errno
|
|---|
| 224 | raise IOError(errno.EBADF, "write() on read-only GzipFile object")
|
|---|
| 225 |
|
|---|
| 226 | if self.fileobj is None:
|
|---|
| 227 | raise ValueError, "write() on closed GzipFile object"
|
|---|
| 228 |
|
|---|
| 229 | # Convert data type if called by io.BufferedWriter.
|
|---|
| 230 | if isinstance(data, memoryview):
|
|---|
| 231 | data = data.tobytes()
|
|---|
| 232 |
|
|---|
| 233 | if len(data) > 0:
|
|---|
| 234 | self.size = self.size + len(data)
|
|---|
| 235 | self.crc = zlib.crc32(data, self.crc) & 0xffffffffL
|
|---|
| 236 | self.fileobj.write( self.compress.compress(data) )
|
|---|
| 237 | self.offset += len(data)
|
|---|
| 238 |
|
|---|
| 239 | return len(data)
|
|---|
| 240 |
|
|---|
| 241 | def read(self, size=-1):
|
|---|
| 242 | self._check_closed()
|
|---|
| 243 | if self.mode != READ:
|
|---|
| 244 | import errno
|
|---|
| 245 | raise IOError(errno.EBADF, "read() on write-only GzipFile object")
|
|---|
| 246 |
|
|---|
| 247 | if self.extrasize <= 0 and self.fileobj is None:
|
|---|
| 248 | return ''
|
|---|
| 249 |
|
|---|
| 250 | readsize = 1024
|
|---|
| 251 | if size < 0: # get the whole thing
|
|---|
| 252 | try:
|
|---|
| 253 | while True:
|
|---|
| 254 | self._read(readsize)
|
|---|
| 255 | readsize = min(self.max_read_chunk, readsize * 2)
|
|---|
| 256 | except EOFError:
|
|---|
| 257 | size = self.extrasize
|
|---|
| 258 | else: # just get some more of it
|
|---|
| 259 | try:
|
|---|
| 260 | while size > self.extrasize:
|
|---|
| 261 | self._read(readsize)
|
|---|
| 262 | readsize = min(self.max_read_chunk, readsize * 2)
|
|---|
| 263 | except EOFError:
|
|---|
| 264 | if size > self.extrasize:
|
|---|
| 265 | size = self.extrasize
|
|---|
| 266 |
|
|---|
| 267 | offset = self.offset - self.extrastart
|
|---|
| 268 | chunk = self.extrabuf[offset: offset + size]
|
|---|
| 269 | self.extrasize = self.extrasize - size
|
|---|
| 270 |
|
|---|
| 271 | self.offset += size
|
|---|
| 272 | return chunk
|
|---|
| 273 |
|
|---|
| 274 | def _unread(self, buf):
|
|---|
| 275 | self.extrasize = len(buf) + self.extrasize
|
|---|
| 276 | self.offset -= len(buf)
|
|---|
| 277 |
|
|---|
| 278 | def _read(self, size=1024):
|
|---|
| 279 | if self.fileobj is None:
|
|---|
| 280 | raise EOFError, "Reached EOF"
|
|---|
| 281 |
|
|---|
| 282 | if self._new_member:
|
|---|
| 283 | # If the _new_member flag is set, we have to
|
|---|
| 284 | # jump to the next member, if there is one.
|
|---|
| 285 | #
|
|---|
| 286 | # First, check if we're at the end of the file;
|
|---|
| 287 | # if so, it's time to stop; no more members to read.
|
|---|
| 288 | pos = self.fileobj.tell() # Save current position
|
|---|
| 289 | self.fileobj.seek(0, 2) # Seek to end of file
|
|---|
| 290 | if pos == self.fileobj.tell():
|
|---|
| 291 | raise EOFError, "Reached EOF"
|
|---|
| 292 | else:
|
|---|
| 293 | self.fileobj.seek( pos ) # Return to original position
|
|---|
| 294 |
|
|---|
| 295 | self._init_read()
|
|---|
| 296 | self._read_gzip_header()
|
|---|
| 297 | self.decompress = zlib.decompressobj(-zlib.MAX_WBITS)
|
|---|
| 298 | self._new_member = False
|
|---|
| 299 |
|
|---|
| 300 | # Read a chunk of data from the file
|
|---|
| 301 | buf = self.fileobj.read(size)
|
|---|
| 302 |
|
|---|
| 303 | # If the EOF has been reached, flush the decompression object
|
|---|
| 304 | # and mark this object as finished.
|
|---|
| 305 |
|
|---|
| 306 | if buf == "":
|
|---|
| 307 | uncompress = self.decompress.flush()
|
|---|
| 308 | self._read_eof()
|
|---|
| 309 | self._add_read_data( uncompress )
|
|---|
| 310 | raise EOFError, 'Reached EOF'
|
|---|
| 311 |
|
|---|
| 312 | uncompress = self.decompress.decompress(buf)
|
|---|
| 313 | self._add_read_data( uncompress )
|
|---|
| 314 |
|
|---|
| 315 | if self.decompress.unused_data != "":
|
|---|
| 316 | # Ending case: we've come to the end of a member in the file,
|
|---|
| 317 | # so seek back to the start of the unused data, finish up
|
|---|
| 318 | # this member, and read a new gzip header.
|
|---|
| 319 | # (The number of bytes to seek back is the length of the unused
|
|---|
| 320 | # data, minus 8 because _read_eof() will rewind a further 8 bytes)
|
|---|
| 321 | self.fileobj.seek( -len(self.decompress.unused_data)+8, 1)
|
|---|
| 322 |
|
|---|
| 323 | # Check the CRC and file size, and set the flag so we read
|
|---|
| 324 | # a new member on the next call
|
|---|
| 325 | self._read_eof()
|
|---|
| 326 | self._new_member = True
|
|---|
| 327 |
|
|---|
| 328 | def _add_read_data(self, data):
|
|---|
| 329 | self.crc = zlib.crc32(data, self.crc) & 0xffffffffL
|
|---|
| 330 | offset = self.offset - self.extrastart
|
|---|
| 331 | self.extrabuf = self.extrabuf[offset:] + data
|
|---|
| 332 | self.extrasize = self.extrasize + len(data)
|
|---|
| 333 | self.extrastart = self.offset
|
|---|
| 334 | self.size = self.size + len(data)
|
|---|
| 335 |
|
|---|
| 336 | def _read_eof(self):
|
|---|
| 337 | # We've read to the end of the file, so we have to rewind in order
|
|---|
| 338 | # to reread the 8 bytes containing the CRC and the file size.
|
|---|
| 339 | # We check the that the computed CRC and size of the
|
|---|
| 340 | # uncompressed data matches the stored values. Note that the size
|
|---|
| 341 | # stored is the true file size mod 2**32.
|
|---|
| 342 | self.fileobj.seek(-8, 1)
|
|---|
| 343 | crc32 = read32(self.fileobj)
|
|---|
| 344 | isize = read32(self.fileobj) # may exceed 2GB
|
|---|
| 345 | if crc32 != self.crc:
|
|---|
| 346 | raise IOError("CRC check failed %s != %s" % (hex(crc32),
|
|---|
| 347 | hex(self.crc)))
|
|---|
| 348 | elif isize != (self.size & 0xffffffffL):
|
|---|
| 349 | raise IOError, "Incorrect length of data produced"
|
|---|
| 350 |
|
|---|
| 351 | # Gzip files can be padded with zeroes and still have archives.
|
|---|
| 352 | # Consume all zero bytes and set the file position to the first
|
|---|
| 353 | # non-zero byte. See http://www.gzip.org/#faq8
|
|---|
| 354 | c = "\x00"
|
|---|
| 355 | while c == "\x00":
|
|---|
| 356 | c = self.fileobj.read(1)
|
|---|
| 357 | if c:
|
|---|
| 358 | self.fileobj.seek(-1, 1)
|
|---|
| 359 |
|
|---|
| 360 | @property
|
|---|
| 361 | def closed(self):
|
|---|
| 362 | return self.fileobj is None
|
|---|
| 363 |
|
|---|
| 364 | def close(self):
|
|---|
| 365 | if self.fileobj is None:
|
|---|
| 366 | return
|
|---|
| 367 | if self.mode == WRITE:
|
|---|
| 368 | self.fileobj.write(self.compress.flush())
|
|---|
| 369 | write32u(self.fileobj, self.crc)
|
|---|
| 370 | # self.size may exceed 2GB, or even 4GB
|
|---|
| 371 | write32u(self.fileobj, self.size & 0xffffffffL)
|
|---|
| 372 | self.fileobj = None
|
|---|
| 373 | elif self.mode == READ:
|
|---|
| 374 | self.fileobj = None
|
|---|
| 375 | if self.myfileobj:
|
|---|
| 376 | self.myfileobj.close()
|
|---|
| 377 | self.myfileobj = None
|
|---|
| 378 |
|
|---|
| 379 | def flush(self,zlib_mode=zlib.Z_SYNC_FLUSH):
|
|---|
| 380 | self._check_closed()
|
|---|
| 381 | if self.mode == WRITE:
|
|---|
| 382 | # Ensure the compressor's buffer is flushed
|
|---|
| 383 | self.fileobj.write(self.compress.flush(zlib_mode))
|
|---|
| 384 | self.fileobj.flush()
|
|---|
| 385 |
|
|---|
| 386 | def fileno(self):
|
|---|
| 387 | """Invoke the underlying file object's fileno() method.
|
|---|
| 388 |
|
|---|
| 389 | This will raise AttributeError if the underlying file object
|
|---|
| 390 | doesn't support fileno().
|
|---|
| 391 | """
|
|---|
| 392 | return self.fileobj.fileno()
|
|---|
| 393 |
|
|---|
| 394 | def rewind(self):
|
|---|
| 395 | '''Return the uncompressed stream file position indicator to the
|
|---|
| 396 | beginning of the file'''
|
|---|
| 397 | if self.mode != READ:
|
|---|
| 398 | raise IOError("Can't rewind in write mode")
|
|---|
| 399 | self.fileobj.seek(0)
|
|---|
| 400 | self._new_member = True
|
|---|
| 401 | self.extrabuf = ""
|
|---|
| 402 | self.extrasize = 0
|
|---|
| 403 | self.extrastart = 0
|
|---|
| 404 | self.offset = 0
|
|---|
| 405 |
|
|---|
| 406 | def readable(self):
|
|---|
| 407 | return self.mode == READ
|
|---|
| 408 |
|
|---|
| 409 | def writable(self):
|
|---|
| 410 | return self.mode == WRITE
|
|---|
| 411 |
|
|---|
| 412 | def seekable(self):
|
|---|
| 413 | return True
|
|---|
| 414 |
|
|---|
| 415 | def seek(self, offset, whence=0):
|
|---|
| 416 | if whence:
|
|---|
| 417 | if whence == 1:
|
|---|
| 418 | offset = self.offset + offset
|
|---|
| 419 | else:
|
|---|
| 420 | raise ValueError('Seek from end not supported')
|
|---|
| 421 | if self.mode == WRITE:
|
|---|
| 422 | if offset < self.offset:
|
|---|
| 423 | raise IOError('Negative seek in write mode')
|
|---|
| 424 | count = offset - self.offset
|
|---|
| 425 | for i in xrange(count // 1024):
|
|---|
| 426 | self.write(1024 * '\0')
|
|---|
| 427 | self.write((count % 1024) * '\0')
|
|---|
| 428 | elif self.mode == READ:
|
|---|
| 429 | if offset < self.offset:
|
|---|
| 430 | # for negative seek, rewind and do positive seek
|
|---|
| 431 | self.rewind()
|
|---|
| 432 | count = offset - self.offset
|
|---|
| 433 | for i in xrange(count // 1024):
|
|---|
| 434 | self.read(1024)
|
|---|
| 435 | self.read(count % 1024)
|
|---|
| 436 |
|
|---|
| 437 | return self.offset
|
|---|
| 438 |
|
|---|
| 439 | def readline(self, size=-1):
|
|---|
| 440 | if size < 0:
|
|---|
| 441 | # Shortcut common case - newline found in buffer.
|
|---|
| 442 | offset = self.offset - self.extrastart
|
|---|
| 443 | i = self.extrabuf.find('\n', offset) + 1
|
|---|
| 444 | if i > 0:
|
|---|
| 445 | self.extrasize -= i - offset
|
|---|
| 446 | self.offset += i - offset
|
|---|
| 447 | return self.extrabuf[offset: i]
|
|---|
| 448 |
|
|---|
| 449 | size = sys.maxint
|
|---|
| 450 | readsize = self.min_readsize
|
|---|
| 451 | else:
|
|---|
| 452 | readsize = size
|
|---|
| 453 | bufs = []
|
|---|
| 454 | while size != 0:
|
|---|
| 455 | c = self.read(readsize)
|
|---|
| 456 | i = c.find('\n')
|
|---|
| 457 |
|
|---|
| 458 | # We set i=size to break out of the loop under two
|
|---|
| 459 | # conditions: 1) there's no newline, and the chunk is
|
|---|
| 460 | # larger than size, or 2) there is a newline, but the
|
|---|
| 461 | # resulting line would be longer than 'size'.
|
|---|
| 462 | if (size <= i) or (i == -1 and len(c) > size):
|
|---|
| 463 | i = size - 1
|
|---|
| 464 |
|
|---|
| 465 | if i >= 0 or c == '':
|
|---|
| 466 | bufs.append(c[:i + 1]) # Add portion of last chunk
|
|---|
| 467 | self._unread(c[i + 1:]) # Push back rest of chunk
|
|---|
| 468 | break
|
|---|
| 469 |
|
|---|
| 470 | # Append chunk to list, decrease 'size',
|
|---|
| 471 | bufs.append(c)
|
|---|
| 472 | size = size - len(c)
|
|---|
| 473 | readsize = min(size, readsize * 2)
|
|---|
| 474 | if readsize > self.min_readsize:
|
|---|
| 475 | self.min_readsize = min(readsize, self.min_readsize * 2, 512)
|
|---|
| 476 | return ''.join(bufs) # Return resulting line
|
|---|
| 477 |
|
|---|
| 478 |
|
|---|
| 479 | def _test():
|
|---|
| 480 | # Act like gzip; with -d, act like gunzip.
|
|---|
| 481 | # The input file is not deleted, however, nor are any other gzip
|
|---|
| 482 | # options or features supported.
|
|---|
| 483 | args = sys.argv[1:]
|
|---|
| 484 | decompress = args and args[0] == "-d"
|
|---|
| 485 | if decompress:
|
|---|
| 486 | args = args[1:]
|
|---|
| 487 | if not args:
|
|---|
| 488 | args = ["-"]
|
|---|
| 489 | for arg in args:
|
|---|
| 490 | if decompress:
|
|---|
| 491 | if arg == "-":
|
|---|
| 492 | f = GzipFile(filename="", mode="rb", fileobj=sys.stdin)
|
|---|
| 493 | g = sys.stdout
|
|---|
| 494 | else:
|
|---|
| 495 | if arg[-3:] != ".gz":
|
|---|
| 496 | print "filename doesn't end in .gz:", repr(arg)
|
|---|
| 497 | continue
|
|---|
| 498 | f = open(arg, "rb")
|
|---|
| 499 | g = __builtin__.open(arg[:-3], "wb")
|
|---|
| 500 | else:
|
|---|
| 501 | if arg == "-":
|
|---|
| 502 | f = sys.stdin
|
|---|
| 503 | g = GzipFile(filename="", mode="wb", fileobj=sys.stdout)
|
|---|
| 504 | else:
|
|---|
| 505 | f = __builtin__.open(arg, "rb")
|
|---|
| 506 | g = open(arg + ".gz", "wb")
|
|---|
| 507 | while True:
|
|---|
| 508 | chunk = f.read(1024)
|
|---|
| 509 | if not chunk:
|
|---|
| 510 | break
|
|---|
| 511 | g.write(chunk)
|
|---|
| 512 | if g is not sys.stdout:
|
|---|
| 513 | g.close()
|
|---|
| 514 | if f is not sys.stdin:
|
|---|
| 515 | f.close()
|
|---|
| 516 |
|
|---|
| 517 | if __name__ == '__main__':
|
|---|
| 518 | _test()
|
|---|
