Merge "Improve evaluate-ahead heuristic" into mnc-dev (4af8dbed) · Commits · e / os / android_packages_apps_ExactCalculator

src/com/android/calculator2/CalculatorExpr.java

+1 −1

Original line number	Diff line number	Diff line
		/*
		* Copyright (C) 2014 The Android Open Source Project
		* Copyright (C) 2015 The Android Open Source Project
		*
		* Licensed under the Apache License, Version 2.0 (the "License");
		* you may not use this file except in compliance with the License.

src/com/android/calculator2/Evaluator.java

+18 −5

Original line number	Diff line number	Diff line
		@@ -143,9 +143,16 @@ class Evaluator {
		// We do use these extra digits to display while we are
		// computing the correct answer. Thus they may be
		// temporarily visible.
		private static final int PRECOMPUTE_DIGITS = 20;
		// Extra digits computed to minimize
		// reevaluations during scrolling.
		private static final int EXTRA_DIVISOR = 5;
		// We add the length of the previous result divided by
		// EXTRA_DIVISOR to try to recover recompute latency when
		// scrolling through a long result.
		private static final int PRECOMPUTE_DIGITS = 30;
		private static final int PRECOMPUTE_DIVISOR = 5;
		// When we have to reevaluate, we compute an extra
		// PRECOMPUTE_DIGITS
		// + <current_result_length>/PRECOMPUTE_DIVISOR digits.
		// The last term is dropped if prec < 0.

		// We cache the result as a string to accelerate scrolling.
		// The cache is filled in by the UI thread, but this may
		@@ -460,6 +467,9 @@ class Evaluator {
		}
		mCurrentReevaluator = new AsyncReevaluator();
		mCacheDigsReq = prec + PRECOMPUTE_DIGITS;
		if (mCache != null) {
		mCacheDigsReq += mCacheDigsReq / PRECOMPUTE_DIVISOR;
		}
		mCurrentReevaluator.execute(mCacheDigsReq);
		}

		@@ -620,12 +630,15 @@ class Evaluator {
		int digs = prec[0];
		mLastDigs = digs;
		// Make sure we eventually get a complete answer
		ensureCachePrec(digs + EXTRA_DIGITS);
		if (mCache == null) {
		// Nothing to do now; seems to happen on rare occasion
		ensureCachePrec(digs + EXTRA_DIGITS);
		// Nothing else to do now; seems to happen on rare occasion
		// with weird user input timing;
		// Will repair itself in a jiffy.
		return getPadding(1);
		} else {
		ensureCachePrec(digs + EXTRA_DIGITS
		+ mCache.length() / EXTRA_DIVISOR);
		}
		// Compute an appropriate substring of mCache.
		// We avoid returning a huge string to minimize string