# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1253211031 -7200
# Node ID 67384f696d3c123ecb45d4ec01439a24a21c7ddb
# Parent  c5a5954934c636efae2cb4aded431962299c19ad
Removed caching since it does not seem to help significantly.
Removed bzip2 compression since zlib is supposed to be better at textual
compression anyway.

diff -r c5a5954934c6 -r 67384f696d3c iixr/files.py
--- a/iixr/files.py	Wed Sep 16 21:12:17 2009 +0200
+++ b/iixr/files.py	Thu Sep 17 20:10:31 2009 +0200
@@ -19,18 +19,10 @@
 """
 
 from iixr.data import vint
-from cStringIO import StringIO
-import bz2, zlib
+import zlib
 
 # Constants.
 
-WRITE_CACHE_SIZE  = 100000
-READ_CACHE_SIZE   = 10000
-READ_CACHE_RESIZE = 5000
-
-compressors = [("b", bz2.compress), ("z", zlib.compress)]
-decompressors = {"b" : bz2.decompress, "z" : zlib.decompress}
-
 class File:
 
     "A basic file abstraction."
@@ -73,8 +65,6 @@
 
     def __init__(self, f):
         File.__init__(self, f)
-        self.cache = StringIO()
-        self.cache_length = 0
 
     def write_number(self, number):
 
@@ -97,14 +87,13 @@
         # Compress the string if requested.
 
         if compress:
-            for flag, fn in compressors:
-                cs = fn(s)
+            cs = zlib.compress(s)
+
+            # Take any shorter than the original.
 
-                # Take the first string shorter than the original.
-
-                if len(cs) < len(s):
-                    s = cs
-                    break
+            if len(cs) < len(s):
+                flag = "z"
+                s = cs
             else:
                 flag = "-"
 
@@ -119,17 +108,10 @@
     # Cache-affected methods.
 
     def write(self, s):
-        self.cache.write(s)
-        if self.cache.tell() >= WRITE_CACHE_SIZE:
-            self.flush()
+        self.f.write(s)
 
     def tell(self):
-        return self.f.tell() + self.cache.tell()
-
-    def flush(self):
-        self.cache.seek(0)
-        self.f.write(self.cache.read())
-        self.cache = StringIO()
+        return self.f.tell()
 
 class FileReader(File):
 
@@ -137,20 +119,6 @@
 
     def __init__(self, f):
         File.__init__(self, f)
-        self.reset_cache(0)
-
-    def reset_cache(self, offset):
-        self.cache = ""
-        self.cache_length = 0
-        self.cache_start = 0
-        self.cache_offset = offset
-        self.f.seek(offset)
-
-    def resize_cache(self, next_start):
-        self.cache = self.cache[next_start:]
-        self.cache_length = len(self.cache)
-        self.cache_start = 0
-        self.cache_offset += next_start
 
     def read_number(self):
 
@@ -194,9 +162,8 @@
 
         # Perform decompression if applicable.
 
-        if flag != "-":
-            fn = decompressors[flag]
-            s = fn(s)
+        if flag == "z":
+            s = zlib.decompress(s)
 
         # Convert strings to Unicode objects.
 
@@ -205,53 +172,13 @@
     # Cache-affected methods.
 
     def read(self, n):
-        needed = n - (self.cache_length - self.cache_start)
-
-        # Read the needed number of characters, if possible.
-
-        if needed > 0:
-            s = self.f.read(max(needed, READ_CACHE_SIZE))
-            self.cache += s
-            self.cache_length += len(s)
-
-        # Get the end of the requested block.
-
-        next_start = self.cache_start + n
-        s = self.cache[self.cache_start:next_start]
-
-        # Reposition the pointer to the cache.
-
-        self._seek_cache(len(s))
-        return s
+        return self.f.read(n)
 
     def tell(self):
-        return self.cache_offset + self.cache_start
+        return self.f.tell()
 
     def seek(self, offset):
-        current = self.tell()
-
-        # If seeking forward, attempt to navigate the cache.
-
-        if offset >= current:
-            self._seek_cache(offset - current)
-        else:
-            self.reset_cache(offset)
-
-    def _seek_cache(self, delta):
-        next_start = self.cache_start + delta
-
-        if next_start > 0 and next_start >= len(self.cache):
-            self.reset_cache(self.cache_offset + next_start)
-
-        # If the cache is too big, resize it.
-
-        elif next_start > READ_CACHE_RESIZE:
-            self.resize_cache(next_start)
-
-        # Otherwise, just reference the next part of the cache.
-
-        else:
-            self.cache_start = next_start
+        self.f.seek(offset)
 
 class FileOpener: