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Patch by Eric Raymond: add an optional 'seekable' flag to the 

MultiFile constructor, and only do the posstack bookkeeping when it is
true.
This commit is contained in:
Guido van Rossum 1998-06-23 14:20:27 +00:00
parent 2d4a54da32
commit 4d40b0a165
1 changed files with 23 additions and 11 deletions
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34
Lib/multifile.py
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@ -21,6 +21,11 @@
# Note that if a nested multipart message is terminated by a separator # Note that if a nested multipart message is terminated by a separator
# for an outer message, this is not reported, even though it is really # for an outer message, this is not reported, even though it is really
# illegal input. # illegal input.
#
# If seekable is given as 0, the class code will not do the bookeeping
# it normally attempts in order to make seeks relative to the beginning of the
# current file part. This may be useful when using MultiFile with a non-
# seekable stream object.
import sys import sys
import string import string
@ -31,13 +36,16 @@ Error = 'multifile.Error'
class MultiFile: class MultiFile:
# #
def __init__(self, fp): seekable = 0
def __init__(self, fp, seekable=1):
self.fp = fp self.fp = fp
self.stack = [] # Grows down self.stack = [] # Grows down
self.level = 0 self.level = 0
self.last = 0 self.last = 0
self.start = self.fp.tell() if seekable:
self.posstack = [] # Grows down self.seekable = 1
self.start = self.fp.tell()
self.posstack = [] # Grows down
# #
def tell(self): def tell(self):
if self.level > 0: if self.level > 0:
@ -88,7 +96,8 @@ class MultiFile:
else: else:
return line return line
# Get here after break out of loop # Get here after break out of loop
self.lastpos = self.tell() - len(line) if self.seekable:
self.lastpos = self.tell() - len(line)
self.level = i+1 self.level = i+1
if self.level > 1: if self.level > 1:
err('*** Missing endmarker in MultiFile.readline()\n') err('*** Missing endmarker in MultiFile.readline()\n')
@ -111,15 +120,17 @@ class MultiFile:
return 0 return 0
self.level = 0 self.level = 0
self.last = 0 self.last = 0
self.start = self.fp.tell() if self.seekable:
self.start = self.fp.tell()
return 1 return 1
# #
def push(self, sep): def push(self, sep):
if self.level > 0: if self.level > 0:
raise Error, 'bad MultiFile.push() call' raise Error, 'bad MultiFile.push() call'
self.stack.insert(0, sep) self.stack.insert(0, sep)
self.posstack.insert(0, self.start) if self.seekable:
self.start = self.fp.tell() self.posstack.insert(0, self.start)
self.start = self.fp.tell()
# #
def pop(self): def pop(self):
if self.stack == []: if self.stack == []:
@ -130,8 +141,9 @@ class MultiFile:
abslastpos = self.lastpos + self.start abslastpos = self.lastpos + self.start
self.level = max(0, self.level - 1) self.level = max(0, self.level - 1)
del self.stack[0] del self.stack[0]
self.start = self.posstack[0] if self.seekable:
del self.posstack[0] self.start = self.posstack[0]
if self.level > 0: del self.posstack[0]
self.lastpos = abslastpos - self.start if self.level > 0:
self.lastpos = abslastpos - self.start
# #