Sjoerd's StringIO speed-up

diff --git a/Lib/StringIO.py b/Lib/StringIO.py
index 12d19a1cbff761ee09839f8edd6cf46d5cf6a640..bbd942854139b97fd3c5245ea22790ac927d8caa 100644 (file)
--- a/Lib/StringIO.py
+++ b/Lib/StringIO.py
@@ -31,6 +31,8 @@ import string
 class StringIO:
        def __init__(self, buf = ''):
                self.buf = buf
+               self.len = len(buf)
+               self.buflist = []
                self.pos = 0
                self.closed = 0
                self.softspace = 0
@@ -41,25 +43,34 @@ class StringIO:
        def isatty(self):
                return 0
        def seek(self, pos, mode = 0):
+               if self.buflist:
+                       self.buf = self.buf + string.joinfields(self.buflist, '')
+                       self.buflist = []
                if mode == 1:
                        pos = pos + self.pos
                elif mode == 2:
-                       pos = pos + len(self.buf)
+                       pos = pos + self.len
                self.pos = max(0, pos)
        def tell(self):
                return self.pos
        def read(self, n = -1):
+               if self.buflist:
+                       self.buf = self.buf + string.joinfields(self.buflist, '')
+                       self.buflist = []
                if n < 0:
-                       newpos = len(self.buf)
+                       newpos = self.len
                else:
-                       newpos = min(self.pos+n, len(self.buf))
+                       newpos = min(self.pos+n, self.len)
                r = self.buf[self.pos:newpos]
                self.pos = newpos
                return r
        def readline(self):
+               if self.buflist:
+                       self.buf = self.buf + string.joinfields(self.buflist, '')
+                       self.buflist = []
                i = string.find(self.buf, '\n', self.pos)
                if i < 0:
-                       newpos = len(self.buf)
+                       newpos = self.len
                else:
                        newpos = i+1
                r = self.buf[self.pos:newpos]
@@ -74,16 +85,28 @@ class StringIO:
                return lines
        def write(self, s):
                if not s: return
-               if self.pos > len(self.buf):
-                       self.buf = self.buf + '\0'*(self.pos - len(self.buf))
+               if self.pos > self.len:
+                       self.buflist.append('\0'*(self.pos - self.len))
+                       self.len = self.pos
                newpos = self.pos + len(s)
-               self.buf = self.buf[:self.pos] + s + self.buf[newpos:]
+               if self.pos < self.len:
+                       if self.buflist:
+                               self.buf = self.buf + string.joinfields(self.buflist, '')
+                               self.buflist = []
+                       self.buflist = [self.buf[:self.pos], s, self.buf[newpos:]]
+                       self.buf = ''
+               else:
+                       self.buflist.append(s)
+                       self.len = newpos
                self.pos = newpos
        def writelines(self, list):
                self.write(string.joinfields(list, ''))
        def flush(self):
                pass
        def getvalue(self):
+               if self.buflist:
+                       self.buf = self.buf + string.joinfields(self.buflist, '')
+                       self.buflist = []
                return self.buf