From f0ba3c482eb937a450cac99b578a6197ed54101b Mon Sep 17 00:00:00 2001
From: Robey Pointer <robey@lag.net>
Date: Thu, 10 Jun 2004 18:02:13 +0000
Subject: [PATCH] [project @
 Arch-1:robey@lag.net--2003-public%secsh--dev--1.0--patch-59] speed up parts
 of BufferedFile BufferedFile uses cStringIO for the write buffer now (i don't
 actually notice any speed difference so this might revert later) and the
 default buffer size has been upped from 1KB to 8KB.

when scanning for linefeeds (when writing to a line-buffered file), only scan
the newly-written bytes, since we know all the previously buffered data is
linefeed-free.  this was the #1 slowdown on the 1MB-file unit test.

also, limit the buffering on line-buffered files to whatever the default
buffer size is.  there's no reason to buffer 1MB waiting for a linefeed.
---
 paramiko/file.py | 34 +++++++++++++++++++++-------------
 1 file changed, 21 insertions(+), 13 deletions(-)

diff --git a/paramiko/file.py b/paramiko/file.py
index 3b9812a..b6b8669 100644
--- a/paramiko/file.py
+++ b/paramiko/file.py
@@ -15,13 +15,15 @@
 # details.
 #
 # You should have received a copy of the GNU Lesser General Public License
-# along with Foobar; if not, write to the Free Software Foundation, Inc.,
+# along with Paramiko; if not, write to the Free Software Foundation, Inc.,
 # 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA.
 
 """
 BufferedFile.
 """
 
+from cStringIO import StringIO
+
 _FLAG_READ = 0x1
 _FLAG_WRITE = 0x2
 _FLAG_APPEND = 0x4
@@ -36,7 +38,7 @@ class BufferedFile (object):
     simpler stream
     """
 
-    _DEFAULT_BUFSIZE = 1024
+    _DEFAULT_BUFSIZE = 8192
 
     SEEK_SET = 0
     SEEK_CUR = 1
@@ -45,7 +47,8 @@ class BufferedFile (object):
     def __init__(self):
         self._flags = 0
         self._bufsize = self._DEFAULT_BUFSIZE
-        self._wbuffer = self._rbuffer = ''
+        self._wbuffer = StringIO()
+        self._rbuffer = ''
         self._at_trailing_cr = False
         self._closed = False
         # pos - position within the file, according to the user
@@ -80,8 +83,8 @@ class BufferedFile (object):
         Write out any data in the write buffer.  This may do nothing if write
         buffering is not turned on.
         """
-        self._write_all(self._wbuffer)
-        self._wbuffer = ''
+        self._write_all(self._wbuffer.getvalue())
+        self._wbuffer = StringIO()
         return
 
     def next(self):
@@ -300,16 +303,21 @@ class BufferedFile (object):
         if not (self._flags & _FLAG_BUFFERED):
             self._write_all(data)
             return
-        self._wbuffer += data
+        self._wbuffer.write(data)
         if self._flags & _FLAG_LINE_BUFFERED:
-            last_newline_pos = self._wbuffer.rfind('\n')
+            # only scan the new data for linefeed, to avoid wasting time.
+            last_newline_pos = data.rfind('\n')
             if last_newline_pos >= 0:
-                self._write_all(self._wbuffer[:last_newline_pos + 1])
-                self._wbuffer = self._wbuffer[last_newline_pos+1:]
-        else:
-            if len(self._wbuffer) >= self._bufsize:
-                self._write_all(self._wbuffer)
-                self._wbuffer = ''
+                wbuf = self._wbuffer.getvalue()
+                last_newline_pos += len(wbuf) - len(data)
+                self._write_all(wbuf[:last_newline_pos + 1])
+                self._wbuffer = StringIO()
+                self._wbuffer.write(wbuf[last_newline_pos+1:])
+            return
+        # even if we're line buffering, if the buffer has grown past the
+        # buffer size, force a flush.
+        if len(self._wbuffer.getvalue()) >= self._bufsize:
+            self.flush()
         return
 
     def writelines(self, sequence):