Fix binary reading code performance.
This is not the Right fix ; the Right fix would be to read
the file in a buffered way. However this delivers tolerable
performance for a minimal amount of code changes.
We may want to skip submitting this patch, but keep it around
in case we need to use the functionality until we have a good
patch.
Change-Id: I1ba938f82acfd9436c3701d1078ff981afdbea60
diff --git a/java/src/com/android/inputmethod/latin/makedict/BinaryDictInputOutput.java b/java/src/com/android/inputmethod/latin/makedict/BinaryDictInputOutput.java
index 97df98e..4256871 100644
--- a/java/src/com/android/inputmethod/latin/makedict/BinaryDictInputOutput.java
+++ b/java/src/com/android/inputmethod/latin/makedict/BinaryDictInputOutput.java
@@ -1122,6 +1122,12 @@
}
}
+ // The word cache here is a stopgap bandaid to help the catastrophic performance
+ // of this method. Since it performs direct, unbuffered random access to the file and
+ // may be called hundreds of thousands of times, the resulting performance is not
+ // reasonable without some kind of cache. Thus:
+ // TODO: perform buffered I/O here and in other places in the code.
+ private static TreeMap<Integer, String> wordCache = new TreeMap<Integer, String>();
/**
* Finds, as a string, the word at the address passed as an argument.
*
@@ -1131,8 +1137,10 @@
* @return the word, as a string.
* @throws IOException if the file can't be read.
*/
- private static String getWordAtAddress(RandomAccessFile source, long headerSize,
+ private static String getWordAtAddress(final RandomAccessFile source, final long headerSize,
int address) throws IOException {
+ final String cachedString = wordCache.get(address);
+ if (null != cachedString) return cachedString;
final long originalPointer = source.getFilePointer();
source.seek(headerSize);
final int count = readCharGroupCount(source);
@@ -1171,6 +1179,7 @@
}
}
source.seek(originalPointer);
+ wordCache.put(address, result);
return result;
}