| /* |
| * Copyright (C) 2016 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. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package com.android.calculator2; |
| |
| import android.content.Context; |
| import android.content.SharedPreferences; |
| import android.net.Uri; |
| import android.os.AsyncTask; |
| import android.os.Handler; |
| import android.preference.PreferenceManager; |
| import android.support.annotation.NonNull; |
| import android.support.annotation.StringRes; |
| import android.support.annotation.VisibleForTesting; |
| import android.text.Spannable; |
| import android.util.Log; |
| |
| import com.hp.creals.CR; |
| |
| import java.io.ByteArrayInputStream; |
| import java.io.DataInput; |
| import java.io.DataInputStream; |
| import java.io.DataOutput; |
| import java.io.IOException; |
| import java.text.DateFormat; |
| import java.text.SimpleDateFormat; |
| import java.util.Date; |
| import java.util.Random; |
| import java.util.TimeZone; |
| import java.util.concurrent.ConcurrentHashMap; |
| import java.util.concurrent.atomic.AtomicReference; |
| |
| /** |
| * This implements the calculator evaluation logic. |
| * Logically this maintains a signed integer indexed set of expressions, one of which |
| * is distinguished as the main expression. |
| * The main expression is constructed and edited with append(), delete(), etc. |
| * An evaluation an then be started with a call to evaluateAndNotify() or requireResult(). |
| * This starts an asynchronous computation, which requests display of the initial result, when |
| * available. When initial evaluation is complete, it calls the associated listener's |
| * onEvaluate() method. This occurs in a separate event, possibly quite a bit later. Once a |
| * result has been computed, and before the underlying expression is modified, the |
| * getString(index) method may be used to produce Strings that represent approximations to various |
| * precisions. |
| * |
| * Actual expressions being evaluated are represented as {@link CalculatorExpr}s. |
| * |
| * The Evaluator holds the expressions and all associated state needed for evaluating |
| * them. It provides functionality for saving and restoring this state. However the underlying |
| * CalculatorExprs are exposed to the client, and may be directly accessed after cancelling any |
| * in-progress computations by invoking the cancelAll() method. |
| * |
| * When evaluation is requested, we invoke the eval() method on the CalculatorExpr from a |
| * background AsyncTask. A subsequent getString() call for the same expression index returns |
| * immediately, though it may return a result containing placeholder ' ' characters. If we had to |
| * return palceholder characters, we start a background task, which invokes the onReevaluate() |
| * callback when it completes. In either case, the background task computes the appropriate |
| * result digits by evaluating the UnifiedReal returned by CalculatorExpr.eval() to the required |
| * precision. |
| * |
| * We cache the best decimal approximation we have already computed. We compute generously to |
| * allow for some scrolling without recomputation and to minimize the chance of digits flipping |
| * from "0000" to "9999". The best known result approximation is maintained as a string by |
| * mResultString (and often in a different format by the CR representation of the result). When |
| * we are in danger of not having digits to display in response to further scrolling, we also |
| * initiate a background computation to higher precision, as if we had generated placeholder |
| * characters. |
| * |
| * The code is designed to ensure that the error in the displayed result (excluding any |
| * placeholder characters) is always strictly less than 1 in the last displayed digit. Typically |
| * we actually display a prefix of a result that has this property and additionally is computed to |
| * a significantly higher precision. Thus we almost always round correctly towards zero. (Fully |
| * correct rounding towards zero is not computable, at least given our representation.) |
| * |
| * Initial expression evaluation may time out. This may happen in the case of domain errors such |
| * as division by zero, or for large computations. We do not currently time out reevaluations to |
| * higher precision, since the original evaluation precluded a domain error that could result in |
| * non-termination. (We may discover that a presumed zero result is actually slightly negative |
| * when re-evaluated; but that results in an exception, which we can handle.) The user can abort |
| * either kind of computation. |
| * |
| * We ensure that only one evaluation of either kind (AsyncEvaluator or AsyncReevaluator) is |
| * running at a time. |
| */ |
| public class Evaluator implements CalculatorExpr.ExprResolver { |
| |
| private static Evaluator evaluator; |
| |
| public static String TIMEOUT_DIALOG_TAG = "timeout"; |
| |
| @NonNull |
| public static Evaluator getInstance(Context context) { |
| if (evaluator == null) { |
| evaluator = new Evaluator(context.getApplicationContext()); |
| } |
| return evaluator; |
| } |
| |
| public interface EvaluationListener { |
| /** |
| * Called if evaluation was explicitly cancelled or evaluation timed out. |
| */ |
| public void onCancelled(long index); |
| /** |
| * Called if evaluation resulted in an error. |
| */ |
| public void onError(long index, int errorId); |
| /** |
| * Called if evaluation completed normally. |
| * @param index index of expression whose evaluation completed |
| * @param initPrecOffset the offset used for initial evaluation |
| * @param msdIndex index of first non-zero digit in the computed result string |
| * @param lsdOffset offset of last digit in result if result has finite decimal |
| * expansion |
| * @param truncatedWholePart the integer part of the result |
| */ |
| public void onEvaluate(long index, int initPrecOffset, int msdIndex, int lsdOffset, |
| String truncatedWholePart); |
| /** |
| * Called in response to a reevaluation request, once more precision is available. |
| * Typically the listener wil respond by calling getString() to retrieve the new |
| * better approximation. |
| */ |
| public void onReevaluate(long index); // More precision is now available; please redraw. |
| } |
| |
| /** |
| * A query interface for derived information based on character widths. |
| * This provides information we need to calculate the "preferred precision offset" used |
| * to display the initial result. It's used to compute the number of digits we can actually |
| * display. All methods are callable from any thread. |
| */ |
| public interface CharMetricsInfo { |
| /** |
| * Return the maximum number of (adjusted, digit-width) characters that will fit in the |
| * result display. May be called asynchronously from non-UI thread. |
| */ |
| public int getMaxChars(); |
| /** |
| * Return the number of additional digit widths required to add digit separators to |
| * the supplied string prefix. |
| * The prefix consists of the first len characters of string s, which is presumed to |
| * represent a whole number. Callable from non-UI thread. |
| * Returns zero if metrics information is not yet available. |
| */ |
| public float separatorChars(String s, int len); |
| /** |
| * Return extra width credit for presence of a decimal point, as fraction of a digit width. |
| * May be called by non-UI thread. |
| */ |
| public float getDecimalCredit(); |
| /** |
| * Return extra width credit for absence of ellipsis, as fraction of a digit width. |
| * May be called by non-UI thread. |
| */ |
| public float getNoEllipsisCredit(); |
| } |
| |
| /** |
| * A CharMetricsInfo that can be used when we are really only interested in computing |
| * short representations to be embedded on formulas. |
| */ |
| private class DummyCharMetricsInfo implements CharMetricsInfo { |
| @Override |
| public int getMaxChars() { |
| return SHORT_TARGET_LENGTH + 10; |
| } |
| @Override |
| public float separatorChars(String s, int len) { |
| return 0; |
| } |
| @Override |
| public float getDecimalCredit() { |
| return 0; |
| } |
| @Override |
| public float getNoEllipsisCredit() { |
| return 0; |
| } |
| } |
| |
| private final DummyCharMetricsInfo mDummyCharMetricsInfo = new DummyCharMetricsInfo(); |
| |
| public static final long MAIN_INDEX = 0; // Index of main expression. |
| // Once final evaluation of an expression is complete, or when we need to save |
| // a partial result, we copy the main expression to a non-zero index. |
| // At that point, the expression no longer changes, and is preserved |
| // until the entire history is cleared. Only expressions at nonzero indices |
| // may be embedded in other expressions. |
| // Each expression index can only have one outstanding evaluation request at a time. |
| // To avoid conflicts between the history and main View, we copy the main expression |
| // to allow independent evaluation by both. |
| public static final long HISTORY_MAIN_INDEX = -1; // Read-only copy of main expression. |
| // To update e.g. "memory" contents, we copy the corresponding expression to a permanent |
| // index, and then remember that index. |
| private long mSavedIndex; // Index of "saved" expression mirroring clipboard. 0 if unused. |
| private long mMemoryIndex; // Index of "memory" expression. 0 if unused. |
| |
| // When naming variables and fields, "Offset" denotes a character offset in a string |
| // representing a decimal number, where the offset is relative to the decimal point. 1 = |
| // tenths position, -1 = units position. Integer.MAX_VALUE is sometimes used for the offset |
| // of the last digit in an a nonterminating decimal expansion. We use the suffix "Index" to |
| // denote a zero-based absolute index into such a string. (In other contexts, like above, |
| // we also use "index" to refer to the key in mExprs below, the list of all known |
| // expressions.) |
| |
| private static final String KEY_PREF_DEGREE_MODE = "degree_mode"; |
| private static final String KEY_PREF_SAVED_INDEX = "saved_index"; |
| private static final String KEY_PREF_MEMORY_INDEX = "memory_index"; |
| private static final String KEY_PREF_SAVED_NAME = "saved_name"; |
| |
| // The minimum number of extra digits we always try to compute to improve the chance of |
| // producing a correctly-rounded-towards-zero result. The extra digits can be displayed to |
| // avoid generating placeholder digits, but should only be displayed briefly while computing. |
| private static final int EXTRA_DIGITS = 20; |
| |
| // We adjust EXTRA_DIGITS by adding the length of the previous result divided by |
| // EXTRA_DIVISOR. This helps hide recompute latency when long results are requested; |
| // We start the recomputation substantially before the need is likely to be visible. |
| private static final int EXTRA_DIVISOR = 5; |
| |
| // In addition to insisting on extra digits (see above), we minimize reevaluation |
| // frequency by precomputing an extra PRECOMPUTE_DIGITS |
| // + <current_precision_offset>/PRECOMPUTE_DIVISOR digits, whenever we are forced to |
| // reevaluate. The last term is dropped if prec < 0. |
| private static final int PRECOMPUTE_DIGITS = 30; |
| private static final int PRECOMPUTE_DIVISOR = 5; |
| |
| // Initial evaluation precision. Enough to guarantee that we can compute the short |
| // representation, and that we rarely have to evaluate nonzero results to MAX_MSD_PREC_OFFSET. |
| // It also helps if this is at least EXTRA_DIGITS + display width, so that we don't |
| // immediately need a second evaluation. |
| private static final int INIT_PREC = 50; |
| |
| // The largest number of digits to the right of the decimal point to which we will evaluate to |
| // compute proper scientific notation for values close to zero. Chosen to ensure that we |
| // always to better than IEEE double precision at identifying nonzeros. And then some. |
| // This is used only when we cannot a priori determine the most significant digit position, as |
| // we always can if we have a rational representation. |
| private static final int MAX_MSD_PREC_OFFSET = 1100; |
| |
| // If we can replace an exponent by this many leading zeroes, we do so. Also used in |
| // estimating exponent size for truncating short representation. |
| private static final int EXP_COST = 3; |
| |
| // Listener that reports changes to the state (empty/filled) of memory. Protected for testing. |
| private Callback mCallback; |
| |
| // Context for database helper. |
| private Context mContext; |
| |
| // A hopefully unique name associated with mSaved. |
| private String mSavedName; |
| |
| // The main expression may have changed since the last evaluation in ways that would affect its |
| // value. |
| private boolean mChangedValue; |
| |
| // The main expression contains trig functions. |
| private boolean mHasTrigFuncs; |
| |
| public static final int INVALID_MSD = Integer.MAX_VALUE; |
| |
| // Used to represent an erroneous result or a required evaluation. Not displayed. |
| private static final String ERRONEOUS_RESULT = "ERR"; |
| |
| /** |
| * An individual CalculatorExpr, together with its evaluation state. |
| * Only the main expression may be changed in-place. The HISTORY_MAIN_INDEX expression is |
| * periodically reset to be a fresh immutable copy of the main expression. |
| * All other expressions are only added and never removed. The expressions themselves are |
| * never modified. |
| * All fields other than mExpr and mVal are touched only by the UI thread. |
| * For MAIN_INDEX, mExpr and mVal may change, but are also only ever touched by the UI thread. |
| * For all other expressions, mExpr does not change once the ExprInfo has been (atomically) |
| * added to mExprs. mVal may be asynchronously set by any thread, but we take care that it |
| * does not change after that. mDegreeMode is handled exactly like mExpr. |
| */ |
| private class ExprInfo { |
| public CalculatorExpr mExpr; // The expression itself. |
| public boolean mDegreeMode; // Evaluating in degree, not radian, mode. |
| public ExprInfo(CalculatorExpr expr, boolean dm) { |
| mExpr = expr; |
| mDegreeMode = dm; |
| mVal = new AtomicReference<UnifiedReal>(); |
| } |
| |
| // Currently running expression evaluator, if any. This is either an AsyncEvaluator |
| // (if mResultString == null or it's obsolete), or an AsyncReevaluator. |
| // We arrange that only one evaluator is active at a time, in part by maintaining |
| // two separate ExprInfo structure for the main and history view, so that they can |
| // arrange for independent evaluators. |
| public AsyncTask mEvaluator; |
| |
| // The remaining fields are valid only if an evaluation completed successfully. |
| // mVal always points to an AtomicReference, but that may be null. |
| public AtomicReference<UnifiedReal> mVal; |
| // We cache the best known decimal result in mResultString. Whenever that is |
| // non-null, it is computed to exactly mResultStringOffset, which is always > 0. |
| // Valid only if mResultString is non-null and (for the main expression) !mChangedValue. |
| // ERRONEOUS_RESULT indicates evaluation resulted in an error. |
| public String mResultString; |
| public int mResultStringOffset = 0; |
| // Number of digits to which (possibly incomplete) evaluation has been requested. |
| // Only accessed by UI thread. |
| public int mResultStringOffsetReq = 0; |
| // Position of most significant digit in current cached result, if determined. This is just |
| // the index in mResultString holding the msd. |
| public int mMsdIndex = INVALID_MSD; |
| // Long timeout needed for evaluation? |
| public boolean mLongTimeout = false; |
| public long mTimeStamp; |
| } |
| |
| private ConcurrentHashMap<Long, ExprInfo> mExprs = new ConcurrentHashMap<Long, ExprInfo>(); |
| |
| // The database holding persistent expressions. |
| private ExpressionDB mExprDB; |
| |
| private ExprInfo mMainExpr; // == mExprs.get(MAIN_INDEX) |
| |
| private SharedPreferences mSharedPrefs; |
| |
| private final Handler mTimeoutHandler; // Used to schedule evaluation timeouts. |
| |
| private void setMainExpr(ExprInfo expr) { |
| mMainExpr = expr; |
| mExprs.put(MAIN_INDEX, expr); |
| } |
| |
| Evaluator(Context context) { |
| mContext = context; |
| setMainExpr(new ExprInfo(new CalculatorExpr(), false)); |
| mSavedName = "none"; |
| mTimeoutHandler = new Handler(); |
| |
| mExprDB = new ExpressionDB(context); |
| mSharedPrefs = PreferenceManager.getDefaultSharedPreferences(context); |
| mMainExpr.mDegreeMode = mSharedPrefs.getBoolean(KEY_PREF_DEGREE_MODE, false); |
| long savedIndex = mSharedPrefs.getLong(KEY_PREF_SAVED_INDEX, 0L); |
| long memoryIndex = mSharedPrefs.getLong(KEY_PREF_MEMORY_INDEX, 0L); |
| if (savedIndex != 0 && savedIndex != -1 /* Recover from old corruption */) { |
| setSavedIndexWhenEvaluated(savedIndex); |
| } |
| if (memoryIndex != 0 && memoryIndex != -1) { |
| setMemoryIndexWhenEvaluated(memoryIndex, false /* no need to persist again */); |
| } |
| mSavedName = mSharedPrefs.getString(KEY_PREF_SAVED_NAME, "none"); |
| } |
| |
| /** |
| * Retrieve minimum expression index. |
| * This is the minimum over all expressions, including uncached ones residing only |
| * in the data base. If no expressions with negative indices were preserved, this will |
| * return a small negative predefined constant. |
| * May be called from any thread, but will block until the database is opened. |
| */ |
| public long getMinIndex() { |
| return mExprDB.getMinIndex(); |
| } |
| |
| /** |
| * Retrieve maximum expression index. |
| * This is the maximum over all expressions, including uncached ones residing only |
| * in the data base. If no expressions with positive indices were preserved, this will |
| * return 0. |
| * May be called from any thread, but will block until the database is opened. |
| */ |
| public long getMaxIndex() { |
| return mExprDB.getMaxIndex(); |
| } |
| |
| /** |
| * Set the Callback for showing dialogs and notifying the UI about memory state changes. |
| * @param callback |
| */ |
| public void setCallback(Callback callback) { |
| mCallback = callback; |
| } |
| |
| /** |
| * Does the expression index refer to a transient and mutable expression? |
| */ |
| private boolean isMutableIndex(long index) { |
| return index == MAIN_INDEX || index == HISTORY_MAIN_INDEX; |
| } |
| |
| /** |
| * Result of initial asynchronous result computation. |
| * Represents either an error or a result computed to an initial evaluation precision. |
| */ |
| private static class InitialResult { |
| public final int errorResourceId; // Error string or INVALID_RES_ID. |
| public final UnifiedReal val; // Constructive real value. |
| public final String newResultString; // Null iff it can't be computed. |
| public final int newResultStringOffset; |
| public final int initDisplayOffset; |
| InitialResult(UnifiedReal v, String s, int p, int idp) { |
| errorResourceId = Calculator.INVALID_RES_ID; |
| val = v; |
| newResultString = s; |
| newResultStringOffset = p; |
| initDisplayOffset = idp; |
| } |
| InitialResult(int errorId) { |
| errorResourceId = errorId; |
| val = UnifiedReal.ZERO; |
| newResultString = "BAD"; |
| newResultStringOffset = 0; |
| initDisplayOffset = 0; |
| } |
| boolean isError() { |
| return errorResourceId != Calculator.INVALID_RES_ID; |
| } |
| } |
| |
| private void displayCancelledMessage() { |
| if (mCallback != null) { |
| mCallback.showMessageDialog(0, R.string.cancelled, 0, null); |
| } |
| } |
| |
| // Timeout handling. |
| // Expressions are evaluated with a sort timeout or a long timeout. |
| // Each implies different maxima on both computation time and bit length. |
| // We recheck bit length separetly to avoid wasting time on decimal conversions that are |
| // destined to fail. |
| |
| /** |
| * Return the timeout in milliseconds. |
| * @param longTimeout a long timeout is in effect |
| */ |
| private long getTimeout(boolean longTimeout) { |
| return longTimeout ? 15000 : 2000; |
| // Exceeding a few tens of seconds increases the risk of running out of memory |
| // and impacting the rest of the system. |
| } |
| |
| /** |
| * Return the maximum number of bits in the result. Longer results are assumed to time out. |
| * @param longTimeout a long timeout is in effect |
| */ |
| private int getMaxResultBits(boolean longTimeout) { |
| return longTimeout ? 700000 : 240000; |
| } |
| |
| /** |
| * Timeout for unrequested, speculative evaluations, in milliseconds. |
| */ |
| private static final long QUICK_TIMEOUT = 1000; |
| |
| /** |
| * Timeout for non-MAIN expressions. Note that there may be many such evaluations in |
| * progress on the same thread or core. Thus the evaluation latency may include that needed |
| * to complete previously enqueued evaluations. Thus the longTimeout flag is not very |
| * meaningful, and currently ignored. |
| * Since this is only used for expressions that we have previously successfully evaluated, |
| * these timeouts hsould never trigger. |
| */ |
| private static final long NON_MAIN_TIMEOUT = 100000; |
| |
| /** |
| * Maximum result bit length for unrequested, speculative evaluations. |
| * Also used to bound evaluation precision for small non-zero fractions. |
| */ |
| private static final int QUICK_MAX_RESULT_BITS = 150000; |
| |
| private void displayTimeoutMessage(boolean longTimeout) { |
| if (mCallback != null) { |
| mCallback.showMessageDialog(R.string.dialog_timeout, R.string.timeout, |
| longTimeout ? 0 : R.string.ok_remove_timeout, TIMEOUT_DIALOG_TAG); |
| } |
| } |
| |
| public void setLongTimeout() { |
| mMainExpr.mLongTimeout = true; |
| } |
| |
| /** |
| * Compute initial cache contents and result when we're good and ready. |
| * We leave the expression display up, with scrolling disabled, until this computation |
| * completes. Can result in an error display if something goes wrong. By default we set a |
| * timeout to catch runaway computations. |
| */ |
| class AsyncEvaluator extends AsyncTask<Void, Void, InitialResult> { |
| private boolean mDm; // degrees |
| public boolean mRequired; // Result was requested by user. |
| private boolean mQuiet; // Suppress cancellation message. |
| private Runnable mTimeoutRunnable = null; |
| private EvaluationListener mListener; // Completion callback. |
| private CharMetricsInfo mCharMetricsInfo; // Where to get result size information. |
| private long mIndex; // Expression index. |
| private ExprInfo mExprInfo; // Current expression. |
| |
| AsyncEvaluator(long index, EvaluationListener listener, CharMetricsInfo cmi, boolean dm, |
| boolean required) { |
| mIndex = index; |
| mListener = listener; |
| mCharMetricsInfo = cmi; |
| mDm = dm; |
| mRequired = required; |
| mQuiet = !required || mIndex != MAIN_INDEX; |
| mExprInfo = mExprs.get(mIndex); |
| if (mExprInfo.mEvaluator != null) { |
| throw new AssertionError("Evaluation already in progress!"); |
| } |
| } |
| |
| private void handleTimeout() { |
| // Runs in UI thread. |
| boolean running = (getStatus() != AsyncTask.Status.FINISHED); |
| if (running && cancel(true)) { |
| mExprs.get(mIndex).mEvaluator = null; |
| if (mRequired && mIndex == MAIN_INDEX) { |
| // Replace mExpr with clone to avoid races if task still runs for a while. |
| mMainExpr.mExpr = (CalculatorExpr)mMainExpr.mExpr.clone(); |
| suppressCancelMessage(); |
| displayTimeoutMessage(mExprInfo.mLongTimeout); |
| } |
| } |
| } |
| |
| private void suppressCancelMessage() { |
| mQuiet = true; |
| } |
| |
| @Override |
| protected void onPreExecute() { |
| long timeout = mRequired ? getTimeout(mExprInfo.mLongTimeout) : QUICK_TIMEOUT; |
| if (mIndex != MAIN_INDEX) { |
| // We evaluated the expression before with the current timeout, so this shouldn't |
| // ever time out. We evaluate it with a ridiculously long timeout to avoid running |
| // down the battery if something does go wrong. But we only log such timeouts, and |
| // invoke the listener with onCancelled. |
| timeout = NON_MAIN_TIMEOUT; |
| } |
| mTimeoutRunnable = new Runnable() { |
| @Override |
| public void run() { |
| handleTimeout(); |
| } |
| }; |
| mTimeoutHandler.removeCallbacks(mTimeoutRunnable); |
| mTimeoutHandler.postDelayed(mTimeoutRunnable, timeout); |
| } |
| |
| /** |
| * Is a computed result too big for decimal conversion? |
| */ |
| private boolean isTooBig(UnifiedReal res) { |
| final int maxBits = mRequired ? getMaxResultBits(mExprInfo.mLongTimeout) |
| : QUICK_MAX_RESULT_BITS; |
| return res.approxWholeNumberBitsGreaterThan(maxBits); |
| } |
| |
| @Override |
| protected InitialResult doInBackground(Void... nothing) { |
| try { |
| // mExpr does not change while we are evaluating; thus it's OK to read here. |
| UnifiedReal res = mExprInfo.mVal.get(); |
| if (res == null) { |
| try { |
| res = mExprInfo.mExpr.eval(mDm, Evaluator.this); |
| if (isCancelled()) { |
| // TODO: This remains very slightly racey. Fix this. |
| throw new CR.AbortedException(); |
| } |
| res = putResultIfAbsent(mIndex, res); |
| } catch (StackOverflowError e) { |
| // Absurdly large integer exponents can cause this. There might be other |
| // examples as well. Treat it as a timeout. |
| return new InitialResult(R.string.timeout); |
| } |
| } |
| if (isTooBig(res)) { |
| // Avoid starting a long uninterruptible decimal conversion. |
| return new InitialResult(R.string.timeout); |
| } |
| int precOffset = INIT_PREC; |
| String initResult = res.toStringTruncated(precOffset); |
| int msd = getMsdIndexOf(initResult); |
| if (msd == INVALID_MSD) { |
| int leadingZeroBits = res.leadingBinaryZeroes(); |
| if (leadingZeroBits < QUICK_MAX_RESULT_BITS) { |
| // Enough initial nonzero digits for most displays. |
| precOffset = 30 + |
| (int)Math.ceil(Math.log(2.0d) / Math.log(10.0d) * leadingZeroBits); |
| initResult = res.toStringTruncated(precOffset); |
| msd = getMsdIndexOf(initResult); |
| if (msd == INVALID_MSD) { |
| throw new AssertionError("Impossible zero result"); |
| } |
| } else { |
| // Just try once more at higher fixed precision. |
| precOffset = MAX_MSD_PREC_OFFSET; |
| initResult = res.toStringTruncated(precOffset); |
| msd = getMsdIndexOf(initResult); |
| } |
| } |
| final int lsdOffset = getLsdOffset(res, initResult, initResult.indexOf('.')); |
| final int initDisplayOffset = getPreferredPrec(initResult, msd, lsdOffset, |
| mCharMetricsInfo); |
| final int newPrecOffset = initDisplayOffset + EXTRA_DIGITS; |
| if (newPrecOffset > precOffset) { |
| precOffset = newPrecOffset; |
| initResult = res.toStringTruncated(precOffset); |
| } |
| return new InitialResult(res, initResult, precOffset, initDisplayOffset); |
| } catch (CalculatorExpr.SyntaxException e) { |
| return new InitialResult(R.string.error_syntax); |
| } catch (UnifiedReal.ZeroDivisionException e) { |
| return new InitialResult(R.string.error_zero_divide); |
| } catch(ArithmeticException e) { |
| return new InitialResult(R.string.error_nan); |
| } catch(CR.PrecisionOverflowException e) { |
| // Extremely unlikely unless we're actually dividing by zero or the like. |
| return new InitialResult(R.string.error_overflow); |
| } catch(CR.AbortedException e) { |
| return new InitialResult(R.string.error_aborted); |
| } |
| } |
| |
| @Override |
| protected void onPostExecute(InitialResult result) { |
| mExprInfo.mEvaluator = null; |
| mTimeoutHandler.removeCallbacks(mTimeoutRunnable); |
| if (result.isError()) { |
| if (result.errorResourceId == R.string.timeout) { |
| // Emulating timeout due to large result. |
| if (mRequired && mIndex == MAIN_INDEX) { |
| displayTimeoutMessage(mExprs.get(mIndex).mLongTimeout); |
| } |
| mListener.onCancelled(mIndex); |
| } else { |
| if (mRequired) { |
| mExprInfo.mResultString = ERRONEOUS_RESULT; |
| } |
| mListener.onError(mIndex, result.errorResourceId); |
| } |
| return; |
| } |
| // mExprInfo.mVal was already set asynchronously by child thread. |
| mExprInfo.mResultString = result.newResultString; |
| mExprInfo.mResultStringOffset = result.newResultStringOffset; |
| final int dotIndex = mExprInfo.mResultString.indexOf('.'); |
| String truncatedWholePart = mExprInfo.mResultString.substring(0, dotIndex); |
| // Recheck display precision; it may change, since display dimensions may have been |
| // unknow the first time. In that case the initial evaluation precision should have |
| // been conservative. |
| // TODO: Could optimize by remembering display size and checking for change. |
| int initPrecOffset = result.initDisplayOffset; |
| mExprInfo.mMsdIndex = getMsdIndexOf(mExprInfo.mResultString); |
| final int leastDigOffset = getLsdOffset(result.val, mExprInfo.mResultString, |
| dotIndex); |
| final int newInitPrecOffset = getPreferredPrec(mExprInfo.mResultString, |
| mExprInfo.mMsdIndex, leastDigOffset, mCharMetricsInfo); |
| if (newInitPrecOffset < initPrecOffset) { |
| initPrecOffset = newInitPrecOffset; |
| } else { |
| // They should be equal. But nothing horrible should happen if they're not. e.g. |
| // because CalculatorResult.MAX_WIDTH was too small. |
| } |
| mListener.onEvaluate(mIndex, initPrecOffset, mExprInfo.mMsdIndex, leastDigOffset, |
| truncatedWholePart); |
| } |
| |
| @Override |
| protected void onCancelled(InitialResult result) { |
| // Invoker resets mEvaluator. |
| mTimeoutHandler.removeCallbacks(mTimeoutRunnable); |
| if (!mQuiet) { |
| displayCancelledMessage(); |
| } // Otherwise, if mRequired, timeout processing displayed message. |
| mListener.onCancelled(mIndex); |
| // Just drop the evaluation; Leave expression displayed. |
| return; |
| } |
| } |
| |
| /** |
| * Check whether a new higher precision result flips previously computed trailing 9s |
| * to zeroes. If so, flip them back. Return the adjusted result. |
| * Assumes newPrecOffset >= oldPrecOffset > 0. |
| * Since our results are accurate to < 1 ulp, this can only happen if the true result |
| * is less than the new result with trailing zeroes, and thus appending 9s to the |
| * old result must also be correct. Such flips are impossible if the newly computed |
| * digits consist of anything other than zeroes. |
| * It is unclear that there are real cases in which this is necessary, |
| * but we have failed to prove there aren't such cases. |
| */ |
| @VisibleForTesting |
| public static String unflipZeroes(String oldDigs, int oldPrecOffset, String newDigs, |
| int newPrecOffset) { |
| final int oldLen = oldDigs.length(); |
| if (oldDigs.charAt(oldLen - 1) != '9') { |
| return newDigs; |
| } |
| final int newLen = newDigs.length(); |
| final int precDiff = newPrecOffset - oldPrecOffset; |
| final int oldLastInNew = newLen - 1 - precDiff; |
| if (newDigs.charAt(oldLastInNew) != '0') { |
| return newDigs; |
| } |
| // Earlier digits could not have changed without a 0 to 9 or 9 to 0 flip at end. |
| // The former is OK. |
| if (!newDigs.substring(newLen - precDiff).equals(StringUtils.repeat('0', precDiff))) { |
| throw new AssertionError("New approximation invalidates old one!"); |
| } |
| return oldDigs + StringUtils.repeat('9', precDiff); |
| } |
| |
| /** |
| * Result of asynchronous reevaluation. |
| */ |
| private static class ReevalResult { |
| public final String newResultString; |
| public final int newResultStringOffset; |
| ReevalResult(String s, int p) { |
| newResultString = s; |
| newResultStringOffset = p; |
| } |
| } |
| |
| /** |
| * Compute new mResultString contents to prec digits to the right of the decimal point. |
| * Ensure that onReevaluate() is called after doing so. If the evaluation fails for reasons |
| * other than a timeout, ensure that onError() is called. |
| * This assumes that initial evaluation of the expression has been successfully |
| * completed. |
| */ |
| private class AsyncReevaluator extends AsyncTask<Integer, Void, ReevalResult> { |
| private long mIndex; // Index of expression to evaluate. |
| private EvaluationListener mListener; |
| private ExprInfo mExprInfo; |
| |
| AsyncReevaluator(long index, EvaluationListener listener) { |
| mIndex = index; |
| mListener = listener; |
| mExprInfo = mExprs.get(mIndex); |
| } |
| |
| @Override |
| protected ReevalResult doInBackground(Integer... prec) { |
| try { |
| final int precOffset = prec[0].intValue(); |
| return new ReevalResult(mExprInfo.mVal.get().toStringTruncated(precOffset), |
| precOffset); |
| } catch(ArithmeticException e) { |
| return null; |
| } catch(CR.PrecisionOverflowException e) { |
| return null; |
| } catch(CR.AbortedException e) { |
| // Should only happen if the task was cancelled, in which case we don't look at |
| // the result. |
| return null; |
| } |
| } |
| |
| @Override |
| protected void onPostExecute(ReevalResult result) { |
| if (result == null) { |
| // This should only be possible in the extremely rare case of encountering a |
| // domain error while reevaluating or in case of a precision overflow. We don't |
| // know of a way to get the latter with a plausible amount of user input. |
| mExprInfo.mResultString = ERRONEOUS_RESULT; |
| mListener.onError(mIndex, R.string.error_nan); |
| } else { |
| if (result.newResultStringOffset < mExprInfo.mResultStringOffset) { |
| throw new AssertionError("Unexpected onPostExecute timing"); |
| } |
| mExprInfo.mResultString = unflipZeroes(mExprInfo.mResultString, |
| mExprInfo.mResultStringOffset, result.newResultString, |
| result.newResultStringOffset); |
| mExprInfo.mResultStringOffset = result.newResultStringOffset; |
| mListener.onReevaluate(mIndex); |
| } |
| mExprInfo.mEvaluator = null; |
| } |
| // On cancellation we do nothing; invoker should have left no trace of us. |
| } |
| |
| /** |
| * If necessary, start an evaluation of the expression at the given index to precOffset. |
| * If we start an evaluation the listener is notified on completion. |
| * Only called if prior evaluation succeeded. |
| */ |
| private void ensureCachePrec(long index, int precOffset, EvaluationListener listener) { |
| ExprInfo ei = mExprs.get(index); |
| if (ei.mResultString != null && ei.mResultStringOffset >= precOffset |
| || ei.mResultStringOffsetReq >= precOffset) return; |
| if (ei.mEvaluator != null) { |
| // Ensure we only have one evaluation running at a time. |
| ei.mEvaluator.cancel(true); |
| ei.mEvaluator = null; |
| } |
| AsyncReevaluator reEval = new AsyncReevaluator(index, listener); |
| ei.mEvaluator = reEval; |
| ei.mResultStringOffsetReq = precOffset + PRECOMPUTE_DIGITS; |
| if (ei.mResultString != null) { |
| ei.mResultStringOffsetReq += ei.mResultStringOffsetReq / PRECOMPUTE_DIVISOR; |
| } |
| reEval.execute(ei.mResultStringOffsetReq); |
| } |
| |
| /** |
| * Return the rightmost nonzero digit position, if any. |
| * @param val UnifiedReal value of result. |
| * @param cache Current cached decimal string representation of result. |
| * @param decIndex Index of decimal point in cache. |
| * @result Position of rightmost nonzero digit relative to decimal point. |
| * Integer.MIN_VALUE if we cannot determine. Integer.MAX_VALUE if there is no lsd, |
| * or we cannot determine it. |
| */ |
| static int getLsdOffset(UnifiedReal val, String cache, int decIndex) { |
| if (val.definitelyZero()) return Integer.MIN_VALUE; |
| int result = val.digitsRequired(); |
| if (result == 0) { |
| int i; |
| for (i = -1; decIndex + i > 0 && cache.charAt(decIndex + i) == '0'; --i) { } |
| result = i; |
| } |
| return result; |
| } |
| |
| // TODO: We may want to consistently specify the position of the current result |
| // window using the left-most visible digit index instead of the offset for the rightmost one. |
| // It seems likely that would simplify the logic. |
| |
| /** |
| * Retrieve the preferred precision "offset" for the currently displayed result. |
| * May be called from non-UI thread. |
| * @param cache Current approximation as string. |
| * @param msd Position of most significant digit in result. Index in cache. |
| * Can be INVALID_MSD if we haven't found it yet. |
| * @param lastDigitOffset Position of least significant digit (1 = tenths digit) |
| * or Integer.MAX_VALUE. |
| */ |
| private static int getPreferredPrec(String cache, int msd, int lastDigitOffset, |
| CharMetricsInfo cm) { |
| final int lineLength = cm.getMaxChars(); |
| final int wholeSize = cache.indexOf('.'); |
| final float rawSepChars = cm.separatorChars(cache, wholeSize); |
| final float rawSepCharsNoDecimal = rawSepChars - cm.getNoEllipsisCredit(); |
| final float rawSepCharsWithDecimal = rawSepCharsNoDecimal - cm.getDecimalCredit(); |
| final int sepCharsNoDecimal = (int) Math.ceil(Math.max(rawSepCharsNoDecimal, 0.0f)); |
| final int sepCharsWithDecimal = (int) Math.ceil(Math.max(rawSepCharsWithDecimal, 0.0f)); |
| final int negative = cache.charAt(0) == '-' ? 1 : 0; |
| // Don't display decimal point if result is an integer. |
| if (lastDigitOffset == 0) { |
| lastDigitOffset = -1; |
| } |
| if (lastDigitOffset != Integer.MAX_VALUE) { |
| if (wholeSize <= lineLength - sepCharsNoDecimal && lastDigitOffset <= 0) { |
| // Exact integer. Prefer to display as integer, without decimal point. |
| return -1; |
| } |
| if (lastDigitOffset >= 0 |
| && wholeSize + lastDigitOffset + 1 /* decimal pt. */ |
| <= lineLength - sepCharsWithDecimal) { |
| // Display full exact number without scientific notation. |
| return lastDigitOffset; |
| } |
| } |
| if (msd > wholeSize && msd <= wholeSize + EXP_COST + 1) { |
| // Display number without scientific notation. Treat leading zero as msd. |
| msd = wholeSize - 1; |
| } |
| if (msd > QUICK_MAX_RESULT_BITS) { |
| // Display a probable but uncertain 0 as "0.000000000", without exponent. That's a |
| // judgment call, but less likely to confuse naive users. A more informative and |
| // confusing option would be to use a large negative exponent. |
| // Treat extremely large msd values as unknown to avoid slow computations. |
| return lineLength - 2; |
| } |
| // Return position corresponding to having msd at left, effectively presuming scientific |
| // notation that preserves the left part of the result. |
| // After adjustment for the space required by an exponent, evaluating to the resulting |
| // precision should not overflow the display. |
| int result = msd - wholeSize + lineLength - negative - 1; |
| if (wholeSize <= lineLength - sepCharsNoDecimal) { |
| // Fits without scientific notation; will need space for separators. |
| if (wholeSize < lineLength - sepCharsWithDecimal) { |
| result -= sepCharsWithDecimal; |
| } else { |
| result -= sepCharsNoDecimal; |
| } |
| } |
| return result; |
| } |
| |
| private static final int SHORT_TARGET_LENGTH = 8; |
| private static final String SHORT_UNCERTAIN_ZERO = "0.00000" + KeyMaps.ELLIPSIS; |
| |
| /** |
| * Get a short representation of the value represented by the string cache. |
| * We try to match the CalculatorResult code when the result is finite |
| * and small enough to suit our needs. |
| * The result is not internationalized. |
| * @param cache String approximation of value. Assumed to be long enough |
| * that if it doesn't contain enough significant digits, we can |
| * reasonably abbreviate as SHORT_UNCERTAIN_ZERO. |
| * @param msdIndex Index of most significant digit in cache, or INVALID_MSD. |
| * @param lsdOffset Position of least significant digit in finite representation, |
| * relative to decimal point, or MAX_VALUE. |
| */ |
| private static String getShortString(String cache, int msdIndex, int lsdOffset) { |
| // This somewhat mirrors the display formatting code, but |
| // - The constants are different, since we don't want to use the whole display. |
| // - This is an easier problem, since we don't support scrolling and the length |
| // is a bit flexible. |
| // TODO: Think about refactoring this to remove partial redundancy with CalculatorResult. |
| final int dotIndex = cache.indexOf('.'); |
| final int negative = cache.charAt(0) == '-' ? 1 : 0; |
| final String negativeSign = negative == 1 ? "-" : ""; |
| |
| // Ensure we don't have to worry about running off the end of cache. |
| if (msdIndex >= cache.length() - SHORT_TARGET_LENGTH) { |
| msdIndex = INVALID_MSD; |
| } |
| if (msdIndex == INVALID_MSD) { |
| if (lsdOffset < INIT_PREC) { |
| return "0"; |
| } else { |
| return SHORT_UNCERTAIN_ZERO; |
| } |
| } |
| // Avoid scientific notation for small numbers of zeros. |
| // Instead stretch significant digits to include decimal point. |
| if (lsdOffset < -1 && dotIndex - msdIndex + negative <= SHORT_TARGET_LENGTH |
| && lsdOffset >= -CalculatorResult.MAX_TRAILING_ZEROES - 1) { |
| // Whole number that fits in allotted space. |
| // CalculatorResult would not use scientific notation either. |
| lsdOffset = -1; |
| } |
| if (msdIndex > dotIndex) { |
| if (msdIndex <= dotIndex + EXP_COST + 1) { |
| // Preferred display format in this case is with leading zeroes, even if |
| // it doesn't fit entirely. Replicate that here. |
| msdIndex = dotIndex - 1; |
| } else if (lsdOffset <= SHORT_TARGET_LENGTH - negative - 2 |
| && lsdOffset <= CalculatorResult.MAX_LEADING_ZEROES + 1) { |
| // Fraction that fits entirely in allotted space. |
| // CalculatorResult would not use scientific notation either. |
| msdIndex = dotIndex -1; |
| } |
| } |
| int exponent = dotIndex - msdIndex; |
| if (exponent > 0) { |
| // Adjust for the fact that the decimal point itself takes space. |
| exponent--; |
| } |
| if (lsdOffset != Integer.MAX_VALUE) { |
| final int lsdIndex = dotIndex + lsdOffset; |
| final int totalDigits = lsdIndex - msdIndex + negative + 1; |
| if (totalDigits <= SHORT_TARGET_LENGTH && dotIndex > msdIndex && lsdOffset >= -1) { |
| // Fits, no exponent needed. |
| final String wholeWithCommas = StringUtils.addCommas(cache, msdIndex, dotIndex); |
| return negativeSign + wholeWithCommas + cache.substring(dotIndex, lsdIndex + 1); |
| } |
| if (totalDigits <= SHORT_TARGET_LENGTH - 3) { |
| return negativeSign + cache.charAt(msdIndex) + "." |
| + cache.substring(msdIndex + 1, lsdIndex + 1) + "E" + exponent; |
| } |
| } |
| // We need to abbreviate. |
| if (dotIndex > msdIndex && dotIndex < msdIndex + SHORT_TARGET_LENGTH - negative - 1) { |
| final String wholeWithCommas = StringUtils.addCommas(cache, msdIndex, dotIndex); |
| return negativeSign + wholeWithCommas |
| + cache.substring(dotIndex, msdIndex + SHORT_TARGET_LENGTH - negative - 1) |
| + KeyMaps.ELLIPSIS; |
| } |
| // Need abbreviation + exponent |
| return negativeSign + cache.charAt(msdIndex) + "." |
| + cache.substring(msdIndex + 1, msdIndex + SHORT_TARGET_LENGTH - negative - 4) |
| + KeyMaps.ELLIPSIS + "E" + exponent; |
| } |
| |
| /** |
| * Return the most significant digit index in the given numeric string. |
| * Return INVALID_MSD if there are not enough digits to prove the numeric value is |
| * different from zero. As usual, we assume an error of strictly less than 1 ulp. |
| */ |
| public static int getMsdIndexOf(String s) { |
| final int len = s.length(); |
| int nonzeroIndex = -1; |
| for (int i = 0; i < len; ++i) { |
| char c = s.charAt(i); |
| if (c != '-' && c != '.' && c != '0') { |
| nonzeroIndex = i; |
| break; |
| } |
| } |
| if (nonzeroIndex >= 0 && (nonzeroIndex < len - 1 || s.charAt(nonzeroIndex) != '1')) { |
| return nonzeroIndex; |
| } else { |
| return INVALID_MSD; |
| } |
| } |
| |
| /** |
| * Return most significant digit index for the result of the expressin at the given index. |
| * Returns an index in the result character array. Return INVALID_MSD if the current result |
| * is too close to zero to determine the result. |
| * Result is almost consistent through reevaluations: It may increase by one, once. |
| */ |
| private int getMsdIndex(long index) { |
| ExprInfo ei = mExprs.get(index); |
| if (ei.mMsdIndex != INVALID_MSD) { |
| // 0.100000... can change to 0.0999999... We may have to correct once by one digit. |
| if (ei.mResultString.charAt(ei.mMsdIndex) == '0') { |
| ei.mMsdIndex++; |
| } |
| return ei.mMsdIndex; |
| } |
| if (ei.mVal.get().definitelyZero()) { |
| return INVALID_MSD; // None exists |
| } |
| int result = INVALID_MSD; |
| if (ei.mResultString != null) { |
| result = ei.mMsdIndex = getMsdIndexOf(ei.mResultString); |
| } |
| return result; |
| } |
| |
| // Refuse to scroll past the point at which this many digits from the whole number |
| // part of the result are still displayed. Avoids sily displays like 1E1. |
| private static final int MIN_DISPLAYED_DIGS = 5; |
| |
| /** |
| * Return result to precOffset[0] digits to the right of the decimal point. |
| * PrecOffset[0] is updated if the original value is out of range. No exponent or other |
| * indication of precision is added. The result is returned immediately, based on the current |
| * cache contents, but it may contain blanks for unknown digits. It may also use |
| * uncertain digits within EXTRA_DIGITS. If either of those occurred, schedule a reevaluation |
| * and redisplay operation. Uncertain digits never appear to the left of the decimal point. |
| * PrecOffset[0] may be negative to only retrieve digits to the left of the decimal point. |
| * (precOffset[0] = 0 means we include the decimal point, but nothing to the right. |
| * precOffset[0] = -1 means we drop the decimal point and start at the ones position. Should |
| * not be invoked before the onEvaluate() callback is received. This essentially just returns |
| * a substring of the full result; a leading minus sign or leading digits can be dropped. |
| * Result uses US conventions; is NOT internationalized. Use getResult() and UnifiedReal |
| * operations to determine whether the result is exact, or whether we dropped trailing digits. |
| * |
| * @param index Index of expression to approximate |
| * @param precOffset Zeroth element indicates desired and actual precision |
| * @param maxPrecOffset Maximum adjusted precOffset[0] |
| * @param maxDigs Maximum length of result |
| * @param truncated Zeroth element is set if leading nonzero digits were dropped |
| * @param negative Zeroth element is set of the result is negative. |
| * @param listener EvaluationListener to notify when reevaluation is complete. |
| */ |
| public String getString(long index, int[] precOffset, int maxPrecOffset, int maxDigs, |
| boolean[] truncated, boolean[] negative, EvaluationListener listener) { |
| ExprInfo ei = mExprs.get(index); |
| int currentPrecOffset = precOffset[0]; |
| // Make sure we eventually get a complete answer |
| if (ei.mResultString == null) { |
| ensureCachePrec(index, currentPrecOffset + EXTRA_DIGITS, listener); |
| // Nothing else to do now; seems to happen on rare occasion with weird user input |
| // timing; Will repair itself in a jiffy. |
| return " "; |
| } else { |
| ensureCachePrec(index, currentPrecOffset + EXTRA_DIGITS + ei.mResultString.length() |
| / EXTRA_DIVISOR, listener); |
| } |
| // Compute an appropriate substring of mResultString. Pad if necessary. |
| final int len = ei.mResultString.length(); |
| final boolean myNegative = ei.mResultString.charAt(0) == '-'; |
| negative[0] = myNegative; |
| // Don't scroll left past leftmost digits in mResultString unless that still leaves an |
| // integer. |
| int integralDigits = len - ei.mResultStringOffset; |
| // includes 1 for dec. pt |
| if (myNegative) { |
| --integralDigits; |
| } |
| int minPrecOffset = Math.min(MIN_DISPLAYED_DIGS - integralDigits, -1); |
| currentPrecOffset = Math.min(Math.max(currentPrecOffset, minPrecOffset), |
| maxPrecOffset); |
| precOffset[0] = currentPrecOffset; |
| int extraDigs = ei.mResultStringOffset - currentPrecOffset; // trailing digits to drop |
| int deficit = 0; // The number of digits we're short |
| if (extraDigs < 0) { |
| extraDigs = 0; |
| deficit = Math.min(currentPrecOffset - ei.mResultStringOffset, maxDigs); |
| } |
| int endIndex = len - extraDigs; |
| if (endIndex < 1) { |
| return " "; |
| } |
| int startIndex = Math.max(endIndex + deficit - maxDigs, 0); |
| truncated[0] = (startIndex > getMsdIndex(index)); |
| String result = ei.mResultString.substring(startIndex, endIndex); |
| if (deficit > 0) { |
| result += StringUtils.repeat(' ', deficit); |
| // Blank character is replaced during translation. |
| // Since we always compute past the decimal point, this never fills in the spot |
| // where the decimal point should go, and we can otherwise treat placeholders |
| // as though they were digits. |
| } |
| return result; |
| } |
| |
| /** |
| * Clear the cache for the main expression. |
| */ |
| private void clearMainCache() { |
| mMainExpr.mVal.set(null); |
| mMainExpr.mResultString = null; |
| mMainExpr.mResultStringOffset = mMainExpr.mResultStringOffsetReq = 0; |
| mMainExpr.mMsdIndex = INVALID_MSD; |
| } |
| |
| |
| public void clearMain() { |
| mMainExpr.mExpr.clear(); |
| mHasTrigFuncs = false; |
| clearMainCache(); |
| mMainExpr.mLongTimeout = false; |
| } |
| |
| public void clearEverything() { |
| boolean dm = mMainExpr.mDegreeMode; |
| cancelAll(true); |
| setSavedIndex(0); |
| setMemoryIndex(0); |
| mExprDB.eraseAll(); |
| mExprs.clear(); |
| setMainExpr(new ExprInfo(new CalculatorExpr(), dm)); |
| } |
| |
| /** |
| * Start asynchronous evaluation. |
| * Invoke listener on successful completion. If the result is required, invoke |
| * onCancelled() if cancelled. |
| * @param index index of expression to be evaluated. |
| * @param required result was explicitly requested by user. |
| */ |
| private void evaluateResult(long index, EvaluationListener listener, CharMetricsInfo cmi, |
| boolean required) { |
| ExprInfo ei = mExprs.get(index); |
| if (index == MAIN_INDEX) { |
| clearMainCache(); |
| } // Otherwise the expression is immutable. |
| AsyncEvaluator eval = new AsyncEvaluator(index, listener, cmi, ei.mDegreeMode, required); |
| ei.mEvaluator = eval; |
| eval.execute(); |
| if (index == MAIN_INDEX) { |
| mChangedValue = false; |
| } |
| } |
| |
| /** |
| * Notify listener of a previously completed evaluation. |
| */ |
| void notifyImmediately(long index, ExprInfo ei, EvaluationListener listener, |
| CharMetricsInfo cmi) { |
| final int dotIndex = ei.mResultString.indexOf('.'); |
| final String truncatedWholePart = ei.mResultString.substring(0, dotIndex); |
| final int leastDigOffset = getLsdOffset(ei.mVal.get(), ei.mResultString, dotIndex); |
| final int msdIndex = getMsdIndex(index); |
| final int preferredPrecOffset = getPreferredPrec(ei.mResultString, msdIndex, |
| leastDigOffset, cmi); |
| listener.onEvaluate(index, preferredPrecOffset, msdIndex, leastDigOffset, |
| truncatedWholePart); |
| } |
| |
| /** |
| * Start optional evaluation of expression and display when ready. |
| * @param index of expression to be evaluated. |
| * Can quietly time out without a listener callback. |
| * No-op if cmi.getMaxChars() == 0. |
| */ |
| public void evaluateAndNotify(long index, EvaluationListener listener, CharMetricsInfo cmi) { |
| if (cmi.getMaxChars() == 0) { |
| // Probably shouldn't happen. If it does, we didn't promise to do anything anyway. |
| return; |
| } |
| ExprInfo ei = ensureExprIsCached(index); |
| if (ei.mResultString != null && ei.mResultString != ERRONEOUS_RESULT |
| && !(index == MAIN_INDEX && mChangedValue)) { |
| // Already done. Just notify. |
| notifyImmediately(MAIN_INDEX, mMainExpr, listener, cmi); |
| return; |
| } else if (ei.mEvaluator != null) { |
| // We only allow a single listener per expression, so this request must be redundant. |
| return; |
| } |
| evaluateResult(index, listener, cmi, false); |
| } |
| |
| /** |
| * Start required evaluation of expression at given index and call back listener when ready. |
| * If index is MAIN_INDEX, we may also directly display a timeout message. |
| * Uses longer timeouts than optional evaluation. |
| * Requires cmi.getMaxChars() != 0. |
| */ |
| public void requireResult(long index, EvaluationListener listener, CharMetricsInfo cmi) { |
| if (cmi.getMaxChars() == 0) { |
| throw new AssertionError("requireResult called too early"); |
| } |
| ExprInfo ei = ensureExprIsCached(index); |
| if (ei.mResultString == null || (index == MAIN_INDEX && mChangedValue)) { |
| if (index == HISTORY_MAIN_INDEX) { |
| // We don't want to compute a result for HISTORY_MAIN_INDEX that was |
| // not already computed for the main expression. Pretend we timed out. |
| // The error case doesn't get here. |
| listener.onCancelled(index); |
| } else if ((ei.mEvaluator instanceof AsyncEvaluator) |
| && ((AsyncEvaluator)(ei.mEvaluator)).mRequired) { |
| // Duplicate request; ignore. |
| } else { |
| // (Re)start evaluator in requested mode, i.e. with longer timeout. |
| cancel(ei, true); |
| evaluateResult(index, listener, cmi, true); |
| } |
| } else if (ei.mResultString == ERRONEOUS_RESULT) { |
| // Just re-evaluate to generate a new notification. |
| cancel(ei, true); |
| evaluateResult(index, listener, cmi, true); |
| } else { |
| notifyImmediately(index, ei, listener, cmi); |
| } |
| } |
| |
| /** |
| * Whether this expression has explicitly been evaluated (User pressed "=") |
| */ |
| public boolean hasResult(long index) { |
| final ExprInfo ei = ensureExprIsCached(index); |
| return ei.mResultString != null; |
| } |
| |
| /** |
| * Is a reevaluation still in progress? |
| */ |
| public boolean evaluationInProgress(long index) { |
| ExprInfo ei = mExprs.get(index); |
| return ei != null && ei.mEvaluator != null; |
| } |
| |
| /** |
| * Cancel any current background task associated with the given ExprInfo. |
| * @param quiet suppress cancellation message |
| * @return true if we cancelled an initial evaluation |
| */ |
| private boolean cancel(ExprInfo expr, boolean quiet) { |
| if (expr.mEvaluator != null) { |
| if (quiet && (expr.mEvaluator instanceof AsyncEvaluator)) { |
| ((AsyncEvaluator)(expr.mEvaluator)).suppressCancelMessage(); |
| } |
| // Reevaluation in progress. |
| if (expr.mVal.get() != null) { |
| expr.mEvaluator.cancel(true); |
| expr.mResultStringOffsetReq = expr.mResultStringOffset; |
| // Backgound computation touches only constructive reals. |
| // OK not to wait. |
| expr.mEvaluator = null; |
| } else { |
| expr.mEvaluator.cancel(true); |
| if (expr == mMainExpr) { |
| // The expression is modifiable, and the AsyncTask is reading it. |
| // There seems to be no good way to wait for cancellation. |
| // Give ourselves a new copy to work on instead. |
| mMainExpr.mExpr = (CalculatorExpr)mMainExpr.mExpr.clone(); |
| // Approximation of constructive reals should be thread-safe, |
| // so we can let that continue until it notices the cancellation. |
| mChangedValue = true; // Didn't do the expected evaluation. |
| } |
| expr.mEvaluator = null; |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| /** |
| * Cancel any current background task associated with the given ExprInfo. |
| * @param quiet suppress cancellation message |
| * @return true if we cancelled an initial evaluation |
| */ |
| public boolean cancel(long index, boolean quiet) |
| { |
| ExprInfo ei = mExprs.get(index); |
| if (ei == null) { |
| return false; |
| } else { |
| return cancel(ei, quiet); |
| } |
| } |
| |
| public void cancelAll(boolean quiet) { |
| // TODO: May want to keep active evaluators in a HashSet to avoid traversing |
| // all expressions we've looked at. |
| for (ExprInfo expr: mExprs.values()) { |
| cancel(expr, quiet); |
| } |
| } |
| |
| /** |
| * Quietly cancel all evaluations associated with expressions other than the main one. |
| * These are currently the evaluations associated with the history fragment. |
| */ |
| public void cancelNonMain() { |
| // TODO: May want to keep active evaluators in a HashSet to avoid traversing |
| // all expressions we've looked at. |
| for (ExprInfo expr: mExprs.values()) { |
| if (expr != mMainExpr) { |
| cancel(expr, true); |
| } |
| } |
| } |
| |
| /** |
| * Restore the evaluator state, including the current expression. |
| */ |
| public void restoreInstanceState(DataInput in) { |
| mChangedValue = true; |
| try { |
| mMainExpr.mDegreeMode = in.readBoolean(); |
| mMainExpr.mLongTimeout = in.readBoolean(); |
| mMainExpr.mExpr = new CalculatorExpr(in); |
| mHasTrigFuncs = hasTrigFuncs(); |
| } catch (IOException e) { |
| Log.v("Calculator", "Exception while restoring:\n" + e); |
| } |
| } |
| |
| /** |
| * Save the evaluator state, including the expression and any saved value. |
| */ |
| public void saveInstanceState(DataOutput out) { |
| try { |
| out.writeBoolean(mMainExpr.mDegreeMode); |
| out.writeBoolean(mMainExpr.mLongTimeout); |
| mMainExpr.mExpr.write(out); |
| } catch (IOException e) { |
| Log.v("Calculator", "Exception while saving state:\n" + e); |
| } |
| } |
| |
| |
| /** |
| * Append a button press to the main expression. |
| * @param id Button identifier for the character or operator to be added. |
| * @return false if we rejected the insertion due to obvious syntax issues, and the expression |
| * is unchanged; true otherwise |
| */ |
| public boolean append(int id) { |
| if (id == R.id.fun_10pow) { |
| add10pow(); // Handled as macro expansion. |
| return true; |
| } else { |
| mChangedValue = mChangedValue || !KeyMaps.isBinary(id); |
| if (mMainExpr.mExpr.add(id)) { |
| if (!mHasTrigFuncs) { |
| mHasTrigFuncs = KeyMaps.isTrigFunc(id); |
| } |
| return true; |
| } else { |
| return false; |
| } |
| } |
| } |
| |
| /** |
| * Delete last taken from main expression. |
| */ |
| public void delete() { |
| mChangedValue = true; |
| mMainExpr.mExpr.delete(); |
| if (mMainExpr.mExpr.isEmpty()) { |
| mMainExpr.mLongTimeout = false; |
| } |
| mHasTrigFuncs = hasTrigFuncs(); |
| } |
| |
| /** |
| * Set degree mode for main expression. |
| */ |
| public void setDegreeMode(boolean degreeMode) { |
| mChangedValue = true; |
| mMainExpr.mDegreeMode = degreeMode; |
| |
| mSharedPrefs.edit() |
| .putBoolean(KEY_PREF_DEGREE_MODE, degreeMode) |
| .apply(); |
| } |
| |
| /** |
| * Return an ExprInfo for a copy of the expression with the given index. |
| * We remove trailing binary operators in the copy. |
| * mTimeStamp is not copied. |
| */ |
| private ExprInfo copy(long index, boolean copyValue) { |
| ExprInfo fromEi = mExprs.get(index); |
| ExprInfo ei = new ExprInfo((CalculatorExpr)fromEi.mExpr.clone(), fromEi.mDegreeMode); |
| while (ei.mExpr.hasTrailingBinary()) { |
| ei.mExpr.delete(); |
| } |
| if (copyValue) { |
| ei.mVal = new AtomicReference<UnifiedReal>(fromEi.mVal.get()); |
| ei.mResultString = fromEi.mResultString; |
| ei.mResultStringOffset = ei.mResultStringOffsetReq = fromEi.mResultStringOffset; |
| ei.mMsdIndex = fromEi.mMsdIndex; |
| } |
| ei.mLongTimeout = fromEi.mLongTimeout; |
| return ei; |
| } |
| |
| /** |
| * Return an ExprInfo corresponding to the sum of the expressions at the |
| * two indices. |
| * index1 should correspond to an immutable expression, and should thus NOT |
| * be MAIN_INDEX. Index2 may be MAIN_INDEX. Both expressions are presumed |
| * to have been evaluated. The result is unevaluated. |
| * Can return null if evaluation resulted in an error (a very unlikely case). |
| */ |
| private ExprInfo sum(long index1, long index2) { |
| return generalized_sum(index1, index2, R.id.op_add); |
| } |
| |
| /** |
| * Return an ExprInfo corresponding to the subtraction of the value at the subtrahend index |
| * from value at the minuend index (minuend - subtrahend = result). Both are presumed to have |
| * been previously evaluated. The result is unevaluated. Can return null. |
| */ |
| private ExprInfo difference(long minuendIndex, long subtrahendIndex) { |
| return generalized_sum(minuendIndex, subtrahendIndex, R.id.op_sub); |
| } |
| |
| private ExprInfo generalized_sum(long index1, long index2, int op) { |
| // TODO: Consider not collapsing expr2, to save database space. |
| // Note that this is a bit tricky, since our expressions can contain unbalanced lparens. |
| CalculatorExpr result = new CalculatorExpr(); |
| CalculatorExpr collapsed1 = getCollapsedExpr(index1); |
| CalculatorExpr collapsed2 = getCollapsedExpr(index2); |
| if (collapsed1 == null || collapsed2 == null) { |
| return null; |
| } |
| result.append(collapsed1); |
| result.add(op); |
| result.append(collapsed2); |
| ExprInfo resultEi = new ExprInfo(result, false /* dont care about degrees/radians */); |
| resultEi.mLongTimeout = mExprs.get(index1).mLongTimeout |
| || mExprs.get(index2).mLongTimeout; |
| return resultEi; |
| } |
| |
| /** |
| * Add the expression described by the argument to the database. |
| * Returns the new row id in the database. |
| * Fills in timestamp in ei, if it was not previously set. |
| * If in_history is true, add it with a positive index, so it will appear in the history. |
| */ |
| private long addToDB(boolean in_history, ExprInfo ei) { |
| byte[] serializedExpr = ei.mExpr.toBytes(); |
| ExpressionDB.RowData rd = new ExpressionDB.RowData(serializedExpr, ei.mDegreeMode, |
| ei.mLongTimeout, 0); |
| long resultIndex = mExprDB.addRow(!in_history, rd); |
| if (mExprs.get(resultIndex) != null) { |
| throw new AssertionError("result slot already occupied! + Slot = " + resultIndex); |
| } |
| // Add newly assigned date to the cache. |
| ei.mTimeStamp = rd.mTimeStamp; |
| if (resultIndex == MAIN_INDEX) { |
| throw new AssertionError("Should not store main expression"); |
| } |
| mExprs.put(resultIndex, ei); |
| return resultIndex; |
| } |
| |
| /** |
| * Preserve a copy of the expression at old_index at a new index. |
| * This is useful only of old_index is MAIN_INDEX or HISTORY_MAIN_INDEX. |
| * This assumes that initial evaluation completed suceessfully. |
| * @param in_history use a positive index so the result appears in the history. |
| * @return the new index |
| */ |
| public long preserve(long old_index, boolean in_history) { |
| ExprInfo ei = copy(old_index, true); |
| if (ei.mResultString == null || ei.mResultString == ERRONEOUS_RESULT) { |
| throw new AssertionError("Preserving unevaluated expression"); |
| } |
| return addToDB(in_history, ei); |
| } |
| |
| /** |
| * Preserve a copy of the current main expression as the most recent history entry, |
| * assuming it is already in the database, but may have been lost from the cache. |
| */ |
| public void represerve() { |
| long resultIndex = getMaxIndex(); |
| // This requires database access only if the local state was preserved, but we |
| // recreated the Evaluator. That excludes the common cases of device rotation, etc. |
| // TODO: Revisit once we deal with database failures. We could just copy from |
| // MAIN_INDEX instead, but that loses the timestamp. |
| ensureExprIsCached(resultIndex); |
| } |
| |
| /** |
| * Discard previous expression in HISTORY_MAIN_INDEX and replace it by a fresh copy |
| * of the main expression. Note that the HISTORY_MAIN_INDEX expresssion is not preserved |
| * in the database or anywhere else; it is always reconstructed when needed. |
| */ |
| public void copyMainToHistory() { |
| cancel(HISTORY_MAIN_INDEX, true /* quiet */); |
| ExprInfo ei = copy(MAIN_INDEX, true); |
| mExprs.put(HISTORY_MAIN_INDEX, ei); |
| } |
| |
| /** |
| * @return the {@link CalculatorExpr} representation of the result of the given |
| * expression. |
| * The resulting expression contains a single "token" with the pre-evaluated result. |
| * The client should ensure that this is never invoked unless initial evaluation of the |
| * expression has been completed. |
| */ |
| private CalculatorExpr getCollapsedExpr(long index) { |
| long real_index = isMutableIndex(index) ? preserve(index, false) : index; |
| final ExprInfo ei = mExprs.get(real_index); |
| final String rs = ei.mResultString; |
| // An error can occur here only under extremely unlikely conditions. |
| // Check anyway, and just refuse. |
| // rs *should* never be null, but it happens. Check as a workaround to protect against |
| // crashes until we find the root cause (b/34801142) |
| if (rs == ERRONEOUS_RESULT || rs == null) { |
| return null; |
| } |
| final int dotIndex = rs.indexOf('.'); |
| final int leastDigOffset = getLsdOffset(ei.mVal.get(), rs, dotIndex); |
| return ei.mExpr.abbreviate(real_index, |
| getShortString(rs, getMsdIndexOf(rs), leastDigOffset)); |
| } |
| |
| /** |
| * Abbreviate the indicated expression to a pre-evaluated expression node, |
| * and use that as the new main expression. |
| * This should not be called unless the expression was previously evaluated and produced a |
| * non-error result. Pre-evaluated expressions can never represent an expression for which |
| * evaluation to a constructive real diverges. Subsequent re-evaluation will also not |
| * diverge, though it may generate errors of various kinds. E.g. sqrt(-10^-1000) . |
| */ |
| public void collapse(long index) { |
| final boolean longTimeout = mExprs.get(index).mLongTimeout; |
| final CalculatorExpr abbrvExpr = getCollapsedExpr(index); |
| clearMain(); |
| mMainExpr.mExpr.append(abbrvExpr); |
| mMainExpr.mLongTimeout = longTimeout; |
| mChangedValue = true; |
| mHasTrigFuncs = false; // Degree mode no longer affects expression value. |
| } |
| |
| /** |
| * Mark the expression as changed, preventing next evaluation request from being ignored. |
| */ |
| public void touch() { |
| mChangedValue = true; |
| } |
| |
| private abstract class SetWhenDoneListener implements EvaluationListener { |
| private void badCall() { |
| throw new AssertionError("unexpected callback"); |
| } |
| abstract void setNow(); |
| @Override |
| public void onCancelled(long index) {} // Extremely unlikely; leave unset. |
| @Override |
| public void onError(long index, int errorId) {} // Extremely unlikely; leave unset. |
| @Override |
| public void onEvaluate(long index, int initPrecOffset, int msdIndex, int lsdOffset, |
| String truncatedWholePart) { |
| setNow(); |
| } |
| @Override |
| public void onReevaluate(long index) { |
| badCall(); |
| } |
| } |
| |
| private class SetMemoryWhenDoneListener extends SetWhenDoneListener { |
| final long mIndex; |
| final boolean mPersist; |
| SetMemoryWhenDoneListener(long index, boolean persist) { |
| mIndex = index; |
| mPersist = persist; |
| } |
| @Override |
| void setNow() { |
| if (mMemoryIndex != 0) { |
| throw new AssertionError("Overwriting nonzero memory index"); |
| } |
| if (mPersist) { |
| setMemoryIndex(mIndex); |
| } else { |
| mMemoryIndex = mIndex; |
| } |
| } |
| } |
| |
| private class SetSavedWhenDoneListener extends SetWhenDoneListener { |
| final long mIndex; |
| SetSavedWhenDoneListener(long index) { |
| mIndex = index; |
| } |
| @Override |
| void setNow() { |
| mSavedIndex = mIndex; |
| } |
| } |
| |
| /** |
| * Set the local and persistent memory index. |
| */ |
| private void setMemoryIndex(long index) { |
| mMemoryIndex = index; |
| mSharedPrefs.edit() |
| .putLong(KEY_PREF_MEMORY_INDEX, index) |
| .apply(); |
| |
| if (mCallback != null) { |
| mCallback.onMemoryStateChanged(); |
| } |
| } |
| |
| /** |
| * Set the local and persistent saved index. |
| */ |
| private void setSavedIndex(long index) { |
| mSavedIndex = index; |
| mSharedPrefs.edit() |
| .putLong(KEY_PREF_SAVED_INDEX, index) |
| .apply(); |
| } |
| |
| /** |
| * Set mMemoryIndex (possibly including the persistent version) to index when we finish |
| * evaluating the corresponding expression. |
| */ |
| void setMemoryIndexWhenEvaluated(long index, boolean persist) { |
| requireResult(index, new SetMemoryWhenDoneListener(index, persist), mDummyCharMetricsInfo); |
| } |
| |
| /** |
| * Set mSavedIndex (not the persistent version) to index when we finish evaluating |
| * the corresponding expression. |
| */ |
| void setSavedIndexWhenEvaluated(long index) { |
| requireResult(index, new SetSavedWhenDoneListener(index), mDummyCharMetricsInfo); |
| } |
| |
| /** |
| * Save an immutable version of the expression at the given index as the saved value. |
| * mExpr is left alone. Return false if result is unavailable. |
| */ |
| private boolean copyToSaved(long index) { |
| if (mExprs.get(index).mResultString == null |
| || mExprs.get(index).mResultString == ERRONEOUS_RESULT) { |
| return false; |
| } |
| setSavedIndex(isMutableIndex(index) ? preserve(index, false) : index); |
| return true; |
| } |
| |
| /** |
| * Save an immutable version of the expression at the given index as the "memory" value. |
| * The expression at index is presumed to have been evaluated. |
| */ |
| public void copyToMemory(long index) { |
| setMemoryIndex(isMutableIndex(index) ? preserve(index, false) : index); |
| } |
| |
| /** |
| * Save an an expression representing the sum of "memory" and the expression with the |
| * given index. Make mMemoryIndex point to it when we complete evaluating. |
| */ |
| public void addToMemory(long index) { |
| ExprInfo newEi = sum(mMemoryIndex, index); |
| if (newEi != null) { |
| long newIndex = addToDB(false, newEi); |
| mMemoryIndex = 0; // Invalidate while we're evaluating. |
| setMemoryIndexWhenEvaluated(newIndex, true /* persist */); |
| } |
| } |
| |
| /** |
| * Save an an expression representing the subtraction of the expression with the given index |
| * from "memory." Make mMemoryIndex point to it when we complete evaluating. |
| */ |
| public void subtractFromMemory(long index) { |
| ExprInfo newEi = difference(mMemoryIndex, index); |
| if (newEi != null) { |
| long newIndex = addToDB(false, newEi); |
| mMemoryIndex = 0; // Invalidate while we're evaluating. |
| setMemoryIndexWhenEvaluated(newIndex, true /* persist */); |
| } |
| } |
| |
| /** |
| * Return index of "saved" expression, or 0. |
| */ |
| public long getSavedIndex() { |
| return mSavedIndex; |
| } |
| |
| /** |
| * Return index of "memory" expression, or 0. |
| */ |
| public long getMemoryIndex() { |
| return mMemoryIndex; |
| } |
| |
| private Uri uriForSaved() { |
| return new Uri.Builder().scheme("tag") |
| .encodedOpaquePart(mSavedName) |
| .build(); |
| } |
| |
| /** |
| * Save the index expression as the saved location and return a URI describing it. |
| * The URI is used to distinguish this particular result from others we may generate. |
| */ |
| public Uri capture(long index) { |
| if (!copyToSaved(index)) return null; |
| // Generate a new (entirely private) URI for this result. |
| // Attempt to conform to RFC4151, though it's unclear it matters. |
| final TimeZone tz = TimeZone.getDefault(); |
| DateFormat df = new SimpleDateFormat("yyyy-MM-dd"); |
| df.setTimeZone(tz); |
| final String isoDate = df.format(new Date()); |
| mSavedName = "calculator2.android.com," + isoDate + ":" |
| + (new Random().nextInt() & 0x3fffffff); |
| mSharedPrefs.edit() |
| .putString(KEY_PREF_SAVED_NAME, mSavedName) |
| .apply(); |
| return uriForSaved(); |
| } |
| |
| public boolean isLastSaved(Uri uri) { |
| return mSavedIndex != 0 && uri.equals(uriForSaved()); |
| } |
| |
| /** |
| * Append the expression at index as a pre-evaluated expression to the main expression. |
| */ |
| public void appendExpr(long index) { |
| ExprInfo ei = mExprs.get(index); |
| mChangedValue = true; |
| mMainExpr.mLongTimeout |= ei.mLongTimeout; |
| CalculatorExpr collapsed = getCollapsedExpr(index); |
| if (collapsed != null) { |
| mMainExpr.mExpr.append(getCollapsedExpr(index)); |
| } |
| } |
| |
| /** |
| * Add the power of 10 operator to the main expression. |
| * This is treated essentially as a macro expansion. |
| */ |
| private void add10pow() { |
| CalculatorExpr ten = new CalculatorExpr(); |
| ten.add(R.id.digit_1); |
| ten.add(R.id.digit_0); |
| mChangedValue = true; // For consistency. Reevaluation is probably not useful. |
| mMainExpr.mExpr.append(ten); |
| mMainExpr.mExpr.add(R.id.op_pow); |
| } |
| |
| /** |
| * Ensure that the expression with the given index is in mExprs. |
| * We assume that if it's either already in mExprs or mExprDB. |
| * When we're done, the expression in mExprs may still contain references to other |
| * subexpressions that are not yet cached. |
| */ |
| private ExprInfo ensureExprIsCached(long index) { |
| ExprInfo ei = mExprs.get(index); |
| if (ei != null) { |
| return ei; |
| } |
| if (index == MAIN_INDEX) { |
| throw new AssertionError("Main expression should be cached"); |
| } |
| ExpressionDB.RowData row = mExprDB.getRow(index); |
| DataInputStream serializedExpr = |
| new DataInputStream(new ByteArrayInputStream(row.mExpression)); |
| try { |
| ei = new ExprInfo(new CalculatorExpr(serializedExpr), row.degreeMode()); |
| ei.mTimeStamp = row.mTimeStamp; |
| ei.mLongTimeout = row.longTimeout(); |
| } catch(IOException e) { |
| throw new AssertionError("IO Exception without real IO:" + e); |
| } |
| ExprInfo newEi = mExprs.putIfAbsent(index, ei); |
| return newEi == null ? ei : newEi; |
| } |
| |
| @Override |
| public CalculatorExpr getExpr(long index) { |
| return ensureExprIsCached(index).mExpr; |
| } |
| |
| /* |
| * Return timestamp associated with the expression in milliseconds since epoch. |
| * Yields zero if the expression has not been written to or read from the database. |
| */ |
| public long getTimeStamp(long index) { |
| return ensureExprIsCached(index).mTimeStamp; |
| } |
| |
| @Override |
| public boolean getDegreeMode(long index) { |
| return ensureExprIsCached(index).mDegreeMode; |
| } |
| |
| @Override |
| public UnifiedReal getResult(long index) { |
| return ensureExprIsCached(index).mVal.get(); |
| } |
| |
| @Override |
| public UnifiedReal putResultIfAbsent(long index, UnifiedReal result) { |
| ExprInfo ei = mExprs.get(index); |
| if (ei.mVal.compareAndSet(null, result)) { |
| return result; |
| } else { |
| // Cannot change once non-null. |
| return ei.mVal.get(); |
| } |
| } |
| |
| /** |
| * Does the current main expression contain trig functions? |
| * Might its value depend on DEG/RAD mode? |
| */ |
| public boolean hasTrigFuncs() { |
| return mHasTrigFuncs; |
| } |
| |
| /** |
| * Maximum number of characters in a scientific notation exponent. |
| */ |
| private static final int MAX_EXP_CHARS = 8; |
| |
| /** |
| * Return the index of the character after the exponent starting at s[offset]. |
| * Return offset if there is no exponent at that position. |
| * Exponents have syntax E[-]digit* . "E2" and "E-2" are valid. "E+2" and "e2" are not. |
| * We allow any Unicode digits, and either of the commonly used minus characters. |
| */ |
| public static int exponentEnd(String s, int offset) { |
| int i = offset; |
| int len = s.length(); |
| if (i >= len - 1 || s.charAt(i) != 'E') { |
| return offset; |
| } |
| ++i; |
| if (KeyMaps.keyForChar(s.charAt(i)) == R.id.op_sub) { |
| ++i; |
| } |
| if (i == len || !Character.isDigit(s.charAt(i))) { |
| return offset; |
| } |
| ++i; |
| while (i < len && Character.isDigit(s.charAt(i))) { |
| ++i; |
| if (i > offset + MAX_EXP_CHARS) { |
| return offset; |
| } |
| } |
| return i; |
| } |
| |
| /** |
| * Add the exponent represented by s[begin..end) to the constant at the end of current |
| * expression. |
| * The end of the current expression must be a constant. Exponents have the same syntax as |
| * for exponentEnd(). |
| */ |
| public void addExponent(String s, int begin, int end) { |
| int sign = 1; |
| int exp = 0; |
| int i = begin + 1; |
| // We do the decimal conversion ourselves to exactly match exponentEnd() conventions |
| // and handle various kinds of digits on input. Also avoids allocation. |
| if (KeyMaps.keyForChar(s.charAt(i)) == R.id.op_sub) { |
| sign = -1; |
| ++i; |
| } |
| for (; i < end; ++i) { |
| exp = 10 * exp + Character.digit(s.charAt(i), 10); |
| } |
| mMainExpr.mExpr.addExponent(sign * exp); |
| mChangedValue = true; |
| } |
| |
| /** |
| * Generate a String representation of the expression at the given index. |
| * This has the side effect of adding the expression to mExprs. |
| * The expression must exist in the database. |
| */ |
| public String getExprAsString(long index) { |
| return getExprAsSpannable(index).toString(); |
| } |
| |
| public Spannable getExprAsSpannable(long index) { |
| return getExpr(index).toSpannableStringBuilder(mContext); |
| } |
| |
| /** |
| * Generate a String representation of all expressions in the database. |
| * Debugging only. |
| */ |
| public String historyAsString() { |
| final long startIndex = getMinIndex(); |
| final long endIndex = getMaxIndex(); |
| final StringBuilder sb = new StringBuilder(); |
| for (long i = getMinIndex(); i < ExpressionDB.MAXIMUM_MIN_INDEX; ++i) { |
| sb.append(i).append(": ").append(getExprAsString(i)).append("\n"); |
| } |
| for (long i = 1; i < getMaxIndex(); ++i) { |
| sb.append(i).append(": ").append(getExprAsString(i)).append("\n"); |
| } |
| sb.append("Memory index = ").append(getMemoryIndex()); |
| sb.append(" Saved index = ").append(getSavedIndex()).append("\n"); |
| return sb.toString(); |
| } |
| |
| /** |
| * Wait for pending writes to the database to complete. |
| */ |
| public void waitForWrites() { |
| mExprDB.waitForWrites(); |
| } |
| |
| /** |
| * Destroy the current evaluator, forcing getEvaluator to allocate a new one. |
| * This is needed for testing, since Robolectric apparently doesn't let us preserve |
| * an open databse across tests. Cf. https://github.com/robolectric/robolectric/issues/1890 . |
| */ |
| public void destroyEvaluator() { |
| mExprDB.close(); |
| evaluator = null; |
| } |
| |
| public interface Callback { |
| void onMemoryStateChanged(); |
| void showMessageDialog(@StringRes int title, @StringRes int message, |
| @StringRes int positiveButtonLabel, String tag); |
| } |
| } |