When there's no filename, don't make one up.

Added _test() that behaves (a bit) like gzip.
Fix a comment (*sequential* access is okay -- *random* access it out!)

diff --git a/Lib/gzip.py b/Lib/gzip.py
index fe2bf20807bc3fb99cdffeecfd34f9e4f59d12b0..26d32aa2a879164da5d3b0b7e7b046b77cd601d9 100644 (file)
--- a/Lib/gzip.py
+++ b/Lib/gzip.py
@@ -6,7 +6,7 @@ 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,
-# but sequential access is not allowed
+# but random access is not allowed
 
 # based on Andrew Kuchling's minigzip.py distributed with the zlib module
 
@@ -52,7 +52,7 @@ class GzipFile:
            fileobj = self.myfileobj = __builtin__.open(filename, mode or 'r')
         if filename is None:
            if hasattr(fileobj, 'name'): filename = fileobj.name
-           else: filename = 'GzippedFile'
+           else: filename = ''
         if mode is None:
            if hasattr(fileobj, 'mode'): mode = fileobj.mode
            else: mode = 'r'
@@ -98,11 +98,16 @@ class GzipFile:
     def _write_gzip_header(self):
        self.fileobj.write('\037\213')             # magic header
        self.fileobj.write('\010')                 # compression method
-       self.fileobj.write(chr(FNAME))
+       fname = self.filename[:-3]
+       flags = 0
+       if fname:
+           flags = FNAME
+       self.fileobj.write(chr(flags))
        write32(self.fileobj, int(time.time()))
        self.fileobj.write('\002')
        self.fileobj.write('\377')
-       self.fileobj.write(self.filename[:-3] + '\000')
+       if fname:
+           self.fileobj.write(fname + '\000')
 
     def _init_read(self):
        self.crc = zlib.crc32("")
@@ -132,12 +137,12 @@ class GzipFile:
            # Read and discard a null-terminated string containing the filename
            while (1):
                s=self.fileobj.read(1)
-               if s=='\000': break
+               if not s or s=='\000': break
        if flag & FCOMMENT:
            # Read and discard a null-terminated string containing a comment
            while (1):
                s=self.fileobj.read(1)
-               if s=='\000': break
+               if not s or s=='\000': break
        if flag & FHCRC:
            self.fileobj.read(2)     # Read & discard the 16-bit header CRC
 
@@ -251,3 +256,46 @@ class GzipFile:
     def writelines(self, L):
        for line in L:
            self.write(line)
+
+
+def _test():
+    # Act like gzip; with -d, act like gunzip.
+    # The input file is not deleted, however, nor are any other gzip
+    # options or features supported.
+    import sys
+    args = sys.argv[1:]
+    decompress = args and args[0] == "-d"
+    if decompress:
+       args = args[1:]
+    if not args:
+       args = ["-"]
+    for arg in args:
+       if decompress:
+           if arg == "-":
+               f = GzipFile(filename="", mode="rb", fileobj=sys.stdin)
+               g = sys.stdout
+           else:
+               if arg[-3:] != ".gz":
+                   print "filename doesn't end in .gz:", `arg`
+                   continue
+               f = open(arg, "rb")
+               g = __builtin__.open(arg[:-3], "wb")
+       else:
+           if arg == "-":
+               f = sys.stdin
+               g = GzipFile(filename="", mode="wb", fileobj=sys.stdout)
+           else:
+               f = __builtin__.open(arg, "rb")
+               g = open(arg + ".gz", "wb")
+       while 1:
+           chunk = f.read(1024)
+           if not chunk:
+               break
+           g.write(chunk)
+       if g is not sys.stdout:
+           g.close()
+       if f is not sys.stdin:
+           f.close()
+
+if __name__ == '__main__':
+    _test()