# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1252956212 -7200
# Node ID a0f37b0ef3502b8fc3b5715ce1f11f4242036516
# Parent  76bd0bcfa998cf54b8de031b82ff1db309699442
Added constants for various measures.
Prevented unnecessary read cache resets where the cache offset is zero.

diff -r 76bd0bcfa998 -r a0f37b0ef350 iixr.py
--- a/iixr.py	Sat Sep 12 18:48:23 2009 +0200
+++ b/iixr.py	Mon Sep 14 21:23:32 2009 +0200
@@ -39,6 +39,10 @@
 FIELD_INTERVAL    = 100
 FLUSH_INTERVAL    = 10000
 
+WRITE_CACHE_SIZE  = 100000
+READ_CACHE_SIZE   = 10000
+READ_CACHE_RESIZE = 5000
+
 TERM_FILENAMES    = "terms", "terms_index", "positions", "positions_index"
 FIELD_FILENAMES   = "fields", "fields_index"
 
@@ -182,7 +186,7 @@
     def write(self, s):
         self.cache.append(s)
         self.cache_length += len(s)
-        if self.cache_length >= 1000:
+        if self.cache_length >= WRITE_CACHE_SIZE:
             self.flush()
 
     def tell(self):
@@ -264,7 +268,7 @@
         # Read the needed number of characters, if possible.
 
         if needed > 0:
-            s = self.f.read(max(needed, 1000))
+            s = self.f.read(max(needed, READ_CACHE_SIZE))
             self.cache += s
             self.cache_length += len(s)
 
@@ -295,12 +299,12 @@
     def _seek_cache(self, delta):
         next_start = self.cache_start + delta
 
-        if next_start >= len(self.cache):
+        if next_start > 0 and next_start >= len(self.cache):
             self.reset_cache()
 
         # If the cache is too big, resize it.
 
-        elif next_start > 1000:
+        elif next_start > READ_CACHE_RESIZE:
             self.cache = self.cache[next_start:]
             self.cache_length = len(self.cache)
             self.cache_start = 0