Revert gzip readline performance patch #1281707 until a more generic performance improvement can be found
diff --git a/Lib/gzip.py b/Lib/gzip.py
index 8c7870e..3c1ebf2 100644
--- a/Lib/gzip.py
+++ b/Lib/gzip.py
@@ -107,7 +107,6 @@
self.extrabuf = ""
self.extrasize = 0
self.filename = filename
- self.min_readsize = 64 # Starts small, scales exponentially
elif mode[0:1] == 'w' or mode[0:1] == 'a':
self.mode = WRITE
@@ -382,39 +381,32 @@
self.read(count % 1024)
def readline(self, size=-1):
- if size < 0:
- size = sys.maxint # Line can be as long as maxint
- readsize = self.min_readsize # Read from file in small chunks
- else:
- readsize = size # Only read in as much as specified
-
- bufs = ""
-
+ if size < 0: size = sys.maxint
+ bufs = []
+ readsize = min(100, size) # Read from the file in small chunks
while True:
- if size == 0: return bufs # Return line (reached max len)
+ if size == 0:
+ return "".join(bufs) # Return resulting line
c = self.read(readsize)
i = c.find('\n')
+ if size is not None:
+ # We set i=size to break out of the loop under two
+ # conditions: 1) there's no newline, and the chunk is
+ # larger than size, or 2) there is a newline, but the
+ # resulting line would be longer than 'size'.
+ if i==-1 and len(c) > size: i=size-1
+ elif size <= i: i = size -1
- # If there is a newline, or the string is empty
if i >= 0 or c == '':
- if size <= i: i = size - 1 # Another larger than size check
+ bufs.append(c[:i+1]) # Add portion of last chunk
+ self._unread(c[i+1:]) # Push back rest of chunk
+ return ''.join(bufs) # Return resulting line
- self._unread(c[i+1:]) # Push back rest of chunk
-
- return bufs + c[:i+1] # Stored line, plus new segment
-
- # If there is no newline
- else:
- if len(c) > size: i = size - 1 # If lineis larger than size
-
- bufs = bufs + c
- size = size - len(c)
- readsize = min(size, int(readsize * 1.1))
-
- # Optimize future readline() calls
- if readsize > self.min_readsize:
- self.min_readsize = readsize
+ # Append chunk to list, decrease 'size',
+ bufs.append(c)
+ size = size - len(c)
+ readsize = min(size, readsize * 2)
def readlines(self, sizehint=0):
# Negative numbers result in reading all the lines