Add the option to pass an open file object to GzipFile. This obviates

the need for the StringIO subclass.
This commit is contained in:
Guido van Rossum 1997-07-19 20:22:23 +00:00
parent 6576dd6ad6
commit 68de37973f

View file

@ -2,6 +2,7 @@
import string
import zlib
import StringIO
import __builtin__
# implements a python function that reads and writes a gzipped file
# the user of the file doesn't have to worry about the compression,
@ -38,23 +39,31 @@ def read32(input):
v = v + (ord(buf[3]) << 24)
return v
written = []
_py_open = open
def open(filename, mode, compresslevel=9):
def open(filename, mode="r", compresslevel=9):
return GzipFile(filename, mode, compresslevel)
class GzipFile:
def __init__(self, filename, mode='r', compresslevel=9):
if mode == 'r' or mode == 'rb':
myfileobj = None
def __init__(self, filename=None, mode=None,
compresslevel=9, fileobj=None):
if fileobj is None:
fileobj = self.myfileobj = __builtin__.open(filename, mode or 'r')
if filename is None:
if hasattr(fileobj, 'name'): filename = fileobj.name
else: filename = 'GzippedFile'
if mode is None:
if hasattr(fileobj, 'mode'): mode = fileobj.mode
else: mode = 'r'
if mode[0:1] == 'r':
self.mode = READ
self._init_read()
self.filename = filename
self.decompress = zlib.decompressobj(-zlib.MAX_WBITS)
elif mode == 'w' or mode == 'wb':
elif mode[0:1] == 'w':
self.mode = WRITE
self._init_write(filename)
self.compress = zlib.compressobj(compresslevel,
@ -65,7 +74,7 @@ def __init__(self, filename, mode='r', compresslevel=9):
else:
raise ValueError, "Mode " + mode + " not supported"
self.fileobj = _py_open(self.filename,mode)
self.fileobj = fileobj
if self.mode == WRITE:
self._write_gzip_header()
@ -134,6 +143,8 @@ def _read_gzip_header(self):
def write(self,data):
if self.fileobj is None:
raise ValueError, "write() on closed GzipFile object"
if len(data) > 0:
self.size = self.size + len(data)
self.crc = zlib.crc32(data, self.crc)
@ -143,7 +154,7 @@ def writelines(self,lines):
self.write(string.join(lines))
def read(self,size=None):
if self.extrasize <= 0 and self.fileobj.closed:
if self.extrasize <= 0 and self.fileobj is None:
return ''
if not size:
@ -173,7 +184,7 @@ def _read(self):
uncompress = self.decompress.flush()
if uncompress == "":
self._read_eof()
self.fileobj.close()
self.fileobj = None
raise EOFError, 'Reached EOF'
else:
uncompress = self.decompress.decompress(buf)
@ -201,9 +212,12 @@ def close(self):
self.fileobj.write(self.compress.flush())
write32(self.fileobj, self.crc)
write32(self.fileobj, self.size)
self.fileobj.close()
self.fileobj = None
elif self.mode == READ:
self.fileobj.close()
self.fileobj = None
if self.myfileobj:
self.myfileobj.close()
self.myfileobj = None
def flush(self):
self.fileobj.flush()
@ -218,47 +232,22 @@ def isatty(self):
return 0
def readline(self):
# should I bother with this
raise RuntimeError, "not implemented"
# XXX This function isn't implemented in a very efficient way
line=""
while 1:
c = self.read(1)
line = line + c
if c=='\n' or c=="": break
return line
def readlines(self):
# should I bother with this
raise RuntimeError, "not implemented"
class StringIOgz(GzipFile):
"""A StringIO substitute that reads/writes gzipped buffers."""
def __init__(self, buf=None, filename="StringIOgz"):
"""Read/write mode depends on first argument.
If __init__ is passed a buffer, it will treat that as the
gzipped data and set up the StringIO for reading. Without the
initial argument, it will assume a new file for writing.
The filename argument is written in the header of buffers
opened for writing. Not sure that this is useful, but the
GzipFile code expects *some* filename."""
if buf:
self.mode = READ
self._init_read()
self.filename = filename
self.decompress = zlib.decompressobj(-zlib.MAX_WBITS)
self.fileobj = StringIO.StringIO(buf)
else:
self.mode = WRITE
self._init_write(filename)
self.compress = zlib.compressobj(compresslevel,
zlib.DEFLATED,
-zlib.MAX_WBITS,
zlib.DEF_MEM_LEVEL,
0)
self.fileobj = StringIO.StringIO()
if self.mode == WRITE:
self._write_gzip_header()
elif self.mode == READ:
self._read_gzip_header()
L=[]
line = self.readline()
while line!="":
L.append(line)
line = self.readline()
return L
def writelines(self, L):
for line in L:
self.write(line)