Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2015 The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 17 | // |
| 18 | // This implements the calculator evaluation logic. |
| 19 | // An evaluation is started with a call to evaluateAndShowResult(). |
| 20 | // This starts an asynchronous computation, which requests display |
| 21 | // of the initial result, when available. When initial evaluation is |
| 22 | // complete, it calls the calculator onEvaluate() method. |
| 23 | // This occurs in a separate event, and may happen quite a bit |
| 24 | // later. Once a result has been computed, and before the underlying |
| 25 | // expression is modified, the getString method may be used to produce |
| 26 | // Strings that represent approximations to various precisions. |
| 27 | // |
| 28 | // Actual expressions being evaluated are represented as CalculatorExprs, |
| 29 | // which are just slightly preprocessed sequences of keypresses. |
| 30 | // |
| 31 | // The Evaluator owns the expression being edited and associated |
| 32 | // state needed for evaluating it. It provides functionality for |
| 33 | // saving and restoring this state. However the current |
| 34 | // CalculatorExpr is exposed to the client, and may be directly modified |
| 35 | // after cancelling any in-progress computations by invoking the |
| 36 | // cancelAll() method. |
| 37 | // |
| 38 | // When evaluation is requested by the user, we invoke the eval |
| 39 | // method on the CalculatorExpr from a background AsyncTask. |
| 40 | // A subsequent getString() callback returns immediately, though it may |
| 41 | // return a result containing placeholder '?' characters. |
| 42 | // In that case we start a background task, which invokes the |
| 43 | // onReevaluate() callback when it completes. |
| 44 | // In both cases, the background task |
| 45 | // computes the appropriate result digits by evaluating |
| 46 | // the constructive real (CR) returned by CalculatorExpr.eval() |
| 47 | // to the required precision. |
| 48 | // |
| 49 | // We cache the best approximation we have already computed. |
| 50 | // We compute generously to allow for |
| 51 | // some scrolling without recomputation and to minimize the chance of |
| 52 | // digits flipping from "0000" to "9999". The best known |
| 53 | // result approximation is maintained as a string by mCache (and |
| 54 | // in a different format by the CR representation of the result). |
| 55 | // When we are in danger of not having digits to display in response |
| 56 | // to further scrolling, we initiate a background computation to higher |
| 57 | // precision. If we actually do fall behind, we display placeholder |
| 58 | // characters, e.g. '?', and schedule a display update when the computation |
| 59 | // completes. |
| 60 | // The code is designed to ensure that the error in the displayed |
| 61 | // result (excluding any '?' characters) is always strictly less than 1 in |
| 62 | // the last displayed digit. Typically we actually display a prefix |
| 63 | // of a result that has this property and additionally is computed to |
| 64 | // a significantly higher precision. Thus we almost always round correctly |
| 65 | // towards zero. (Fully correct rounding towards zero is not computable.) |
Hans Boehm | c023b73 | 2015-04-29 11:30:47 -0700 | [diff] [blame] | 66 | // |
| 67 | // Initial expression evaluation may time out. This may happen in the |
| 68 | // case of domain errors such as division by zero, or for large computations. |
| 69 | // We do not currently time out reevaluations to higher precision, since |
| 70 | // the original evaluation prevcluded a domain error that could result |
| 71 | // in non-termination. (We may discover that a presumed zero result is |
| 72 | // actually slightly negative when re-evaluated; but that results in an |
| 73 | // exception, which we can handle.) The user can abort either kind |
| 74 | // of computation. |
| 75 | // |
| 76 | // We ensure that only one evaluation of either kind (AsyncReevaluator |
| 77 | // or AsyncDisplayResult) is running at a time. |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 78 | |
| 79 | package com.android.calculator2; |
| 80 | |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 81 | import android.app.AlertDialog; |
| 82 | import android.content.DialogInterface; |
Hans Boehm | 4a6b7cb | 2015-04-03 18:41:52 -0700 | [diff] [blame] | 83 | import android.content.Context; |
| 84 | import android.content.res.Resources; |
| 85 | import android.net.Uri; |
| 86 | import android.os.AsyncTask; |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 87 | import android.os.Handler; |
Hans Boehm | 4a6b7cb | 2015-04-03 18:41:52 -0700 | [diff] [blame] | 88 | import android.text.TextUtils; |
| 89 | import android.util.Log; |
| 90 | import android.view.KeyEvent; |
| 91 | import android.widget.EditText; |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 92 | |
| 93 | import com.hp.creals.CR; |
| 94 | import com.hp.creals.PrecisionOverflowError; |
| 95 | import com.hp.creals.AbortedError; |
| 96 | |
Hans Boehm | 4a6b7cb | 2015-04-03 18:41:52 -0700 | [diff] [blame] | 97 | import java.io.DataInput; |
| 98 | import java.io.DataOutput; |
| 99 | import java.io.IOException; |
| 100 | import java.text.DateFormat; |
| 101 | import java.text.DecimalFormatSymbols; |
| 102 | import java.text.SimpleDateFormat; |
| 103 | import java.math.BigInteger; |
| 104 | import java.util.Date; |
| 105 | import java.util.HashMap; |
| 106 | import java.util.Locale; |
| 107 | import java.util.Map.Entry; |
| 108 | import java.util.Random; |
| 109 | import java.util.Set; |
| 110 | import java.util.TimeZone; |
| 111 | |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 112 | class Evaluator { |
| 113 | private final Calculator mCalculator; |
| 114 | private final CalculatorResult mResult; // The result display View |
| 115 | private CalculatorExpr mExpr; // Current calculator expression |
Hans Boehm | 4a6b7cb | 2015-04-03 18:41:52 -0700 | [diff] [blame] | 116 | private CalculatorExpr mSaved; // Last saved expression. |
| 117 | // Either null or contains a single |
| 118 | // preevaluated node. |
| 119 | private String mSavedName; // A hopefully unique name associated |
| 120 | // with mSaved. |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 121 | // The following are valid only if an evaluation |
| 122 | // completed successfully. |
| 123 | private CR mVal; // value of mExpr as constructive real |
Hans Boehm | 682ff5e | 2015-03-09 14:40:25 -0700 | [diff] [blame] | 124 | private BoundedRational mRatVal; // value of mExpr as rational or null |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 125 | private int mLastDigs; // Last digit argument passed to getString() |
| 126 | // for this result, or the initial preferred |
| 127 | // precision. |
| 128 | private boolean mDegreeMode; // Currently in degree (not radian) mode |
| 129 | private final Handler mTimeoutHandler; |
| 130 | |
| 131 | static final char MINUS = '\u2212'; |
| 132 | |
| 133 | static final BigInteger BIG_MILLION = BigInteger.valueOf(1000000); |
| 134 | |
| 135 | |
| 136 | private final char decimalPt = |
| 137 | DecimalFormatSymbols.getInstance().getDecimalSeparator(); |
| 138 | |
Hans Boehm | 08e8f32 | 2015-04-21 13:18:38 -0700 | [diff] [blame] | 139 | private static final int EXTRA_DIGITS = 20; |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 140 | // Extra computed digits to minimize probably we will have |
| 141 | // to change our minds about digits we already displayed. |
| 142 | // (The correct digits are technically not computable using our |
| 143 | // representation: An off by one error in the last digits |
| 144 | // can affect earlier ones, even though the display is |
| 145 | // always within one in the lsd. This is only visible |
| 146 | // for results that end in EXTRA_DIGITS 9s or 0s, but are |
| 147 | // not integers.) |
| 148 | // We do use these extra digits to display while we are |
| 149 | // computing the correct answer. Thus they may be |
| 150 | // temporarily visible. |
Hans Boehm | 08e8f32 | 2015-04-21 13:18:38 -0700 | [diff] [blame] | 151 | private static final int PRECOMPUTE_DIGITS = 20; |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 152 | // Extra digits computed to minimize |
| 153 | // reevaluations during scrolling. |
| 154 | |
| 155 | // We cache the result as a string to accelerate scrolling. |
| 156 | // The cache is filled in by the UI thread, but this may |
| 157 | // happen asynchronously, much later than the request. |
| 158 | private String mCache; // Current best known result, which includes |
| 159 | private int mCacheDigs = 0; // mCacheDigs digits to the right of the |
| 160 | // decimal point. Always positive. |
| 161 | // mCache is valid when non-null |
| 162 | // unless the expression has been |
| 163 | // changed since the last evaluation call. |
| 164 | private int mCacheDigsReq; // Number of digits that have been |
| 165 | // requested. Only touched by UI |
| 166 | // thread. |
Hans Boehm | 08e8f32 | 2015-04-21 13:18:38 -0700 | [diff] [blame] | 167 | public static final int INVALID_MSD = Integer.MAX_VALUE; |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 168 | private int mMsd = INVALID_MSD; // Position of most significant digit |
| 169 | // in current cached result, if determined. |
| 170 | // This is just the index in mCache |
| 171 | // holding the msd. |
Hans Boehm | 08e8f32 | 2015-04-21 13:18:38 -0700 | [diff] [blame] | 172 | private static final int MAX_MSD_PREC = 100; |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 173 | // The largest number of digits to the right |
| 174 | // of the decimal point to which we will |
| 175 | // evaluate to compute proper scientific |
| 176 | // notation for values close to zero. |
| 177 | |
| 178 | private AsyncReevaluator mCurrentReevaluator; |
| 179 | // The one and only un-cancelled and currently running reevaluator. |
| 180 | // Touched only by UI thread. |
| 181 | |
| 182 | private AsyncDisplayResult mEvaluator; |
| 183 | // Currently running expression evaluator, if any. |
| 184 | |
Hans Boehm | c023b73 | 2015-04-29 11:30:47 -0700 | [diff] [blame] | 185 | private boolean mChangedValue; |
| 186 | // Last insertion or deletion may have changed the display value |
| 187 | // of the expression. |
| 188 | // We handle deletions very conservatively. |
| 189 | |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 190 | Evaluator(Calculator calculator, |
| 191 | CalculatorResult resultDisplay) { |
| 192 | mCalculator = calculator; |
| 193 | mResult = resultDisplay; |
| 194 | mExpr = new CalculatorExpr(); |
Hans Boehm | 4a6b7cb | 2015-04-03 18:41:52 -0700 | [diff] [blame] | 195 | mSaved = new CalculatorExpr(); |
| 196 | mSavedName = "none"; |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 197 | mTimeoutHandler = new Handler(); |
Hans Boehm | bfe8c22 | 2015-04-02 16:26:07 -0700 | [diff] [blame] | 198 | mDegreeMode = false; // Remain compatible with previous versions. |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 199 | } |
| 200 | |
| 201 | // Result of asynchronous reevaluation |
| 202 | class ReevalResult { |
| 203 | ReevalResult(String s, int p) { |
| 204 | mNewCache = s; |
| 205 | mNewCacheDigs = p; |
| 206 | } |
| 207 | final String mNewCache; |
| 208 | final int mNewCacheDigs; |
| 209 | } |
| 210 | |
| 211 | // Compute new cache contents accurate to prec digits to the right |
| 212 | // of the decimal point. Ensure that redisplay() is called after |
| 213 | // doing so. If the evaluation fails for reasons other than a |
| 214 | // timeout, ensure that DisplayError() is called. |
| 215 | class AsyncReevaluator extends AsyncTask<Integer, Void, ReevalResult> { |
| 216 | @Override |
| 217 | protected ReevalResult doInBackground(Integer... prec) { |
| 218 | try { |
| 219 | int eval_prec = prec[0].intValue(); |
| 220 | return new ReevalResult(mVal.toString(eval_prec), eval_prec); |
| 221 | } catch(ArithmeticException e) { |
| 222 | return null; |
| 223 | } catch(PrecisionOverflowError e) { |
| 224 | return null; |
| 225 | } catch(AbortedError e) { |
| 226 | // Should only happen if the task was cancelled, |
| 227 | // in which case we don't look at the result. |
| 228 | return null; |
| 229 | } |
| 230 | } |
| 231 | @Override |
| 232 | protected void onPostExecute(ReevalResult result) { |
| 233 | if (result == null) { |
| 234 | // This should only be possible in the extremely rare |
Hans Boehm | c023b73 | 2015-04-29 11:30:47 -0700 | [diff] [blame] | 235 | // case of encountering a domain error while reevaluating |
| 236 | // or in case of a precision overflow. We don't know of |
| 237 | // a way to get the latter with a plausible amount of |
| 238 | // user input. |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 239 | mCalculator.onError(R.string.error_nan); |
| 240 | } else { |
| 241 | if (result.mNewCacheDigs < mCacheDigs) { |
| 242 | throw new Error("Unexpected onPostExecute timing"); |
| 243 | } |
| 244 | mCache = result.mNewCache; |
| 245 | mCacheDigs = result.mNewCacheDigs; |
| 246 | mCalculator.onReevaluate(); |
| 247 | } |
| 248 | mCurrentReevaluator = null; |
| 249 | } |
| 250 | // On cancellation we do nothing; invoker should have |
| 251 | // left no trace of us. |
| 252 | } |
| 253 | |
| 254 | // Result of initial asynchronous computation |
| 255 | private static class InitialResult { |
Hans Boehm | 682ff5e | 2015-03-09 14:40:25 -0700 | [diff] [blame] | 256 | InitialResult(CR val, BoundedRational ratVal, String s, int p, int idp) { |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 257 | mErrorResourceId = Calculator.INVALID_RES_ID; |
| 258 | mVal = val; |
Hans Boehm | 682ff5e | 2015-03-09 14:40:25 -0700 | [diff] [blame] | 259 | mRatVal = ratVal; |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 260 | mNewCache = s; |
| 261 | mNewCacheDigs = p; |
| 262 | mInitDisplayPrec = idp; |
| 263 | } |
| 264 | InitialResult(int errorResourceId) { |
| 265 | mErrorResourceId = errorResourceId; |
| 266 | mVal = CR.valueOf(0); |
Hans Boehm | 682ff5e | 2015-03-09 14:40:25 -0700 | [diff] [blame] | 267 | mRatVal = BoundedRational.ZERO; |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 268 | mNewCache = "BAD"; |
| 269 | mNewCacheDigs = 0; |
| 270 | mInitDisplayPrec = 0; |
| 271 | } |
| 272 | boolean isError() { |
| 273 | return mErrorResourceId != Calculator.INVALID_RES_ID; |
| 274 | } |
| 275 | final int mErrorResourceId; |
| 276 | final CR mVal; |
Hans Boehm | 682ff5e | 2015-03-09 14:40:25 -0700 | [diff] [blame] | 277 | final BoundedRational mRatVal; |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 278 | final String mNewCache; // Null iff it can't be computed. |
| 279 | final int mNewCacheDigs; |
| 280 | final int mInitDisplayPrec; |
| 281 | } |
| 282 | |
| 283 | private void displayCancelledMessage() { |
Hans Boehm | c023b73 | 2015-04-29 11:30:47 -0700 | [diff] [blame] | 284 | new AlertDialog.Builder(mCalculator) |
| 285 | .setMessage(R.string.cancelled) |
| 286 | .setPositiveButton(android.R.string.ok, |
| 287 | new DialogInterface.OnClickListener() { |
| 288 | public void onClick(DialogInterface d, int which) { } |
| 289 | }) |
| 290 | .create() |
| 291 | .show(); |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 292 | } |
| 293 | |
| 294 | private final long MAX_TIMEOUT = 60000; |
| 295 | // Milliseconds. |
| 296 | // Longer is unlikely to help unless |
| 297 | // we get more heap space. |
| 298 | private long mTimeout = 2000; // Timeout for requested evaluations, |
| 299 | // in milliseconds. |
| 300 | // This is currently not saved and restored |
Hans Boehm | c023b73 | 2015-04-29 11:30:47 -0700 | [diff] [blame] | 301 | // with the state; we reset |
| 302 | // the timeout when the |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 303 | // calculator is restarted. |
| 304 | // We'll call that a feature; others |
| 305 | // might argue it's a bug. |
Hans Boehm | c023b73 | 2015-04-29 11:30:47 -0700 | [diff] [blame] | 306 | private final long mQuickTimeout = 1500; |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 307 | // Timeout for unrequested, speculative |
| 308 | // evaluations, in milliseconds. |
Hans Boehm | c023b73 | 2015-04-29 11:30:47 -0700 | [diff] [blame] | 309 | // Could be shorter with a faster asin() |
| 310 | // implementation. |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 311 | |
| 312 | private void displayTimeoutMessage() { |
Hans Boehm | c023b73 | 2015-04-29 11:30:47 -0700 | [diff] [blame] | 313 | AlertDialog.Builder b = new AlertDialog.Builder(mCalculator); |
| 314 | b.setMessage(R.string.timeout) |
| 315 | .setNegativeButton(android.R.string.ok, |
| 316 | new DialogInterface.OnClickListener() { |
| 317 | public void onClick(DialogInterface d, int which) { } |
| 318 | }); |
| 319 | if (mTimeout != MAX_TIMEOUT) { |
| 320 | b.setPositiveButton(R.string.ok_remove_timeout, |
| 321 | new DialogInterface.OnClickListener() { |
| 322 | public void onClick(DialogInterface d, int which) { |
| 323 | mTimeout = MAX_TIMEOUT; |
| 324 | } |
| 325 | }); |
| 326 | } |
| 327 | b.create().show(); |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 328 | } |
| 329 | |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 330 | // Compute initial cache contents and result when we're good and ready. |
| 331 | // We leave the expression display up, with scrolling |
| 332 | // disabled, until this computation completes. |
| 333 | // Can result in an error display if something goes wrong. |
| 334 | // By default we set a timeout to catch runaway computations. |
| 335 | class AsyncDisplayResult extends AsyncTask<Void, Void, InitialResult> { |
| 336 | private boolean mDm; // degrees |
| 337 | private boolean mRequired; // Result was requested by user. |
Hans Boehm | c023b73 | 2015-04-29 11:30:47 -0700 | [diff] [blame] | 338 | private boolean mTimedOut = false; |
| 339 | private Runnable mTimeoutRunnable = null; |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 340 | AsyncDisplayResult(boolean dm, boolean required) { |
| 341 | mDm = dm; |
| 342 | mRequired = required; |
| 343 | } |
Hans Boehm | c023b73 | 2015-04-29 11:30:47 -0700 | [diff] [blame] | 344 | private void handleTimeOut() { |
| 345 | boolean running = (getStatus() != AsyncTask.Status.FINISHED); |
| 346 | if (running && cancel(true)) { |
| 347 | mEvaluator = null; |
| 348 | // Replace mExpr with clone to avoid races if task |
| 349 | // still runs for a while. |
| 350 | mExpr = (CalculatorExpr)mExpr.clone(); |
| 351 | mTimedOut = true; |
| 352 | if (mRequired) { |
| 353 | displayTimeoutMessage(); |
| 354 | } |
| 355 | } |
| 356 | } |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 357 | @Override |
| 358 | protected void onPreExecute() { |
Hans Boehm | 08e8f32 | 2015-04-21 13:18:38 -0700 | [diff] [blame] | 359 | long timeout = mRequired ? mTimeout : mQuickTimeout; |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 360 | if (timeout != 0) { |
Hans Boehm | c023b73 | 2015-04-29 11:30:47 -0700 | [diff] [blame] | 361 | mTimeoutRunnable = new Runnable() { |
| 362 | @Override |
| 363 | public void run() { |
| 364 | handleTimeOut(); |
| 365 | } |
| 366 | }; |
| 367 | mTimeoutHandler.postDelayed(mTimeoutRunnable, timeout); |
| 368 | mTimedOut = false; |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 369 | } |
| 370 | } |
| 371 | @Override |
| 372 | protected InitialResult doInBackground(Void... nothing) { |
| 373 | try { |
Hans Boehm | c023b73 | 2015-04-29 11:30:47 -0700 | [diff] [blame] | 374 | CalculatorExpr.EvalResult res = mExpr.eval(mDm, mRequired); |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 375 | int prec = 3; // Enough for short representation |
| 376 | String initCache = res.mVal.toString(prec); |
| 377 | int msd = getMsdPos(initCache); |
Hans Boehm | 682ff5e | 2015-03-09 14:40:25 -0700 | [diff] [blame] | 378 | if (BoundedRational.asBigInteger(res.mRatVal) == null |
| 379 | && msd == INVALID_MSD) { |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 380 | prec = MAX_MSD_PREC; |
| 381 | initCache = res.mVal.toString(prec); |
| 382 | msd = getMsdPos(initCache); |
| 383 | } |
Hans Boehm | 682ff5e | 2015-03-09 14:40:25 -0700 | [diff] [blame] | 384 | int initDisplayPrec = |
| 385 | getPreferredPrec(initCache, msd, |
| 386 | BoundedRational.digitsRequired(res.mRatVal)); |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 387 | int newPrec = initDisplayPrec + EXTRA_DIGITS; |
| 388 | if (newPrec > prec) { |
| 389 | prec = newPrec; |
| 390 | initCache = res.mVal.toString(prec); |
| 391 | } |
Hans Boehm | 682ff5e | 2015-03-09 14:40:25 -0700 | [diff] [blame] | 392 | return new InitialResult(res.mVal, res.mRatVal, |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 393 | initCache, prec, initDisplayPrec); |
Hans Boehm | c023b73 | 2015-04-29 11:30:47 -0700 | [diff] [blame] | 394 | } catch (CalculatorExpr.SyntaxException e) { |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 395 | return new InitialResult(R.string.error_syntax); |
Hans Boehm | fbcef70 | 2015-04-27 18:07:47 -0700 | [diff] [blame] | 396 | } catch (BoundedRational.ZeroDivisionException e) { |
| 397 | // Division by zero caught by BoundedRational; |
| 398 | // the easy and more common case. |
| 399 | return new InitialResult(R.string.error_zero_divide); |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 400 | } catch(ArithmeticException e) { |
| 401 | return new InitialResult(R.string.error_nan); |
| 402 | } catch(PrecisionOverflowError e) { |
| 403 | // Extremely unlikely unless we're actually dividing by |
| 404 | // zero or the like. |
| 405 | return new InitialResult(R.string.error_overflow); |
| 406 | } catch(AbortedError e) { |
| 407 | return new InitialResult(R.string.error_aborted); |
| 408 | } |
| 409 | } |
| 410 | @Override |
| 411 | protected void onPostExecute(InitialResult result) { |
| 412 | mEvaluator = null; |
| 413 | mTimeoutHandler.removeCallbacks(mTimeoutRunnable); |
| 414 | if (result.isError()) { |
| 415 | mCalculator.onError(result.mErrorResourceId); |
| 416 | return; |
| 417 | } |
| 418 | mVal = result.mVal; |
Hans Boehm | 682ff5e | 2015-03-09 14:40:25 -0700 | [diff] [blame] | 419 | mRatVal = result.mRatVal; |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 420 | mCache = result.mNewCache; |
| 421 | mCacheDigs = result.mNewCacheDigs; |
| 422 | mLastDigs = result.mInitDisplayPrec; |
| 423 | int dotPos = mCache.indexOf('.'); |
| 424 | String truncatedWholePart = mCache.substring(0, dotPos); |
Hans Boehm | 4a6b7cb | 2015-04-03 18:41:52 -0700 | [diff] [blame] | 425 | // Recheck display precision; it may change, since |
| 426 | // display dimensions may have been unknow the first time. |
| 427 | // In that case the initial evaluation precision should have |
| 428 | // been conservative. |
| 429 | // TODO: Could optimize by remembering display size and |
| 430 | // checking for change. |
| 431 | int init_prec = result.mInitDisplayPrec; |
| 432 | int msd = getMsdPos(mCache); |
| 433 | int new_init_prec = getPreferredPrec(mCache, msd, |
| 434 | BoundedRational.digitsRequired(mRatVal)); |
| 435 | if (new_init_prec < init_prec) { |
| 436 | init_prec = new_init_prec; |
| 437 | } else { |
| 438 | // They should be equal. But nothing horrible should |
| 439 | // happen if they're not. e.g. because |
| 440 | // CalculatorResult.MAX_WIDTH was too small. |
| 441 | } |
| 442 | mCalculator.onEvaluate(init_prec,truncatedWholePart); |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 443 | } |
| 444 | @Override |
| 445 | protected void onCancelled(InitialResult result) { |
Hans Boehm | c023b73 | 2015-04-29 11:30:47 -0700 | [diff] [blame] | 446 | if (mRequired && !mTimedOut) { |
| 447 | displayCancelledMessage(); |
| 448 | } // Otherwise timeout processing displayed message. |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 449 | mCalculator.onCancelled(); |
| 450 | // Just drop the evaluation; Leave expression displayed. |
| 451 | return; |
| 452 | } |
| 453 | } |
| 454 | |
| 455 | |
| 456 | // Start an evaluation to prec, and ensure that the |
| 457 | // display is redrawn when it completes. |
| 458 | private void ensureCachePrec(int prec) { |
| 459 | if (mCache != null && mCacheDigs >= prec |
| 460 | || mCacheDigsReq >= prec) return; |
| 461 | if (mCurrentReevaluator != null) { |
| 462 | // Ensure we only have one evaluation running at a time. |
| 463 | mCurrentReevaluator.cancel(true); |
| 464 | mCurrentReevaluator = null; |
| 465 | } |
| 466 | mCurrentReevaluator = new AsyncReevaluator(); |
| 467 | mCacheDigsReq = prec + PRECOMPUTE_DIGITS; |
| 468 | mCurrentReevaluator.execute(mCacheDigsReq); |
| 469 | } |
| 470 | |
| 471 | // Retrieve the preferred precision for the currently |
| 472 | // displayed result, given the number of characters we |
| 473 | // have room for and the current string approximation for |
| 474 | // the result. |
Hans Boehm | 682ff5e | 2015-03-09 14:40:25 -0700 | [diff] [blame] | 475 | // lastDigit is the position of the last digit on the right |
Hans Boehm | 760a9dc | 2015-04-20 10:27:12 -0700 | [diff] [blame] | 476 | // if there is such a thing, or Integer.MAX_VALUE. |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 477 | // May be called in non-UI thread. |
Hans Boehm | 682ff5e | 2015-03-09 14:40:25 -0700 | [diff] [blame] | 478 | int getPreferredPrec(String cache, int msd, int lastDigit) { |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 479 | int lineLength = mResult.getMaxChars(); |
| 480 | int wholeSize = cache.indexOf('.'); |
Hans Boehm | 682ff5e | 2015-03-09 14:40:25 -0700 | [diff] [blame] | 481 | // Don't display decimal point if result is an integer. |
| 482 | if (lastDigit == 0) lastDigit = -1; |
| 483 | if (lastDigit != Integer.MAX_VALUE |
| 484 | && ((wholeSize <= lineLength && lastDigit == 0) |
| 485 | || wholeSize + lastDigit + 1 /* d.p. */ <= lineLength)) { |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 486 | // Prefer to display as integer, without decimal point |
Hans Boehm | 682ff5e | 2015-03-09 14:40:25 -0700 | [diff] [blame] | 487 | if (lastDigit == 0) return -1; |
| 488 | return lastDigit; |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 489 | } |
| 490 | if (msd > wholeSize && msd <= wholeSize + 4) { |
| 491 | // Display number without scientific notation. |
| 492 | // Treat leading zero as msd. |
| 493 | msd = wholeSize - 1; |
| 494 | } |
Hans Boehm | 760a9dc | 2015-04-20 10:27:12 -0700 | [diff] [blame] | 495 | if (msd > wholeSize + MAX_MSD_PREC) { |
| 496 | // Display a probably but uncertain 0 as "0.000000000", |
| 497 | // without exponent. That's a judgment call, but less likely |
| 498 | // to confuse naive users. A more informative and confusing |
| 499 | // option would be to use a large negative exponent. |
| 500 | return lineLength - 2; |
| 501 | } |
| 502 | return msd - wholeSize + lineLength - 2; |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 503 | } |
| 504 | |
| 505 | // Get a short representation of the value represented by |
| 506 | // the string cache (presumed to contain at least 5 characters) |
| 507 | // and possibly the exact integer i. |
| 508 | private String getShortString(String cache, BigInteger i) { |
Hans Boehm | 013969e | 2015-04-13 20:29:47 -0700 | [diff] [blame] | 509 | // The result is internationalized; we only display it. |
| 510 | String res; |
| 511 | boolean need_ellipsis = false; |
| 512 | |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 513 | if (i != null && i.abs().compareTo(BIG_MILLION) < 0) { |
Hans Boehm | 013969e | 2015-04-13 20:29:47 -0700 | [diff] [blame] | 514 | res = i.toString(); |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 515 | } else { |
Hans Boehm | 013969e | 2015-04-13 20:29:47 -0700 | [diff] [blame] | 516 | res = cache.substring(0,5); |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 517 | // Avoid a trailing period; doesn't work with ellipsis |
| 518 | if (res.charAt(3) != '.') { |
| 519 | res = res.substring(0,4); |
| 520 | } |
Hans Boehm | 013969e | 2015-04-13 20:29:47 -0700 | [diff] [blame] | 521 | // TODO: Don't do this in the unlikely case this is the |
| 522 | // full representation. |
| 523 | need_ellipsis = true; |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 524 | } |
Hans Boehm | 013969e | 2015-04-13 20:29:47 -0700 | [diff] [blame] | 525 | res = KeyMaps.translateResult(res); |
| 526 | if (need_ellipsis) { |
Hans Boehm | 08e8f32 | 2015-04-21 13:18:38 -0700 | [diff] [blame] | 527 | res += KeyMaps.ELLIPSIS; |
Hans Boehm | 013969e | 2015-04-13 20:29:47 -0700 | [diff] [blame] | 528 | } |
| 529 | return res; |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 530 | } |
| 531 | |
| 532 | // Return the most significant digit position in the given string |
| 533 | // or INVALID_MSD. |
Hans Boehm | 08e8f32 | 2015-04-21 13:18:38 -0700 | [diff] [blame] | 534 | public static int getMsdPos(String s) { |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 535 | int len = s.length(); |
| 536 | int nonzeroPos = -1; |
| 537 | for (int i = 0; i < len; ++i) { |
| 538 | char c = s.charAt(i); |
| 539 | if (c != '-' && c != '.' && c != '0') { |
| 540 | nonzeroPos = i; |
| 541 | break; |
| 542 | } |
| 543 | } |
| 544 | if (nonzeroPos >= 0 && |
| 545 | (nonzeroPos < len - 1 || s.charAt(nonzeroPos) != '1')) { |
| 546 | return nonzeroPos; |
| 547 | } else { |
| 548 | // Unknown, or could change on reevaluation |
| 549 | return INVALID_MSD; |
| 550 | } |
| 551 | |
| 552 | } |
| 553 | |
| 554 | // Return most significant digit position in the cache, if determined, |
| 555 | // INVALID_MSD ow. |
| 556 | // If unknown, and we've computed less than DESIRED_PREC, |
| 557 | // schedule reevaluation and redisplay, with higher precision. |
| 558 | int getMsd() { |
| 559 | if (mMsd != INVALID_MSD) return mMsd; |
Hans Boehm | 682ff5e | 2015-03-09 14:40:25 -0700 | [diff] [blame] | 560 | if (mRatVal != null && mRatVal.signum() == 0) { |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 561 | return INVALID_MSD; // None exists |
| 562 | } |
| 563 | int res = INVALID_MSD; |
| 564 | if (mCache != null) { |
| 565 | res = getMsdPos(mCache); |
| 566 | } |
| 567 | if (res == INVALID_MSD && mEvaluator == null |
| 568 | && mCurrentReevaluator == null && mCacheDigs < MAX_MSD_PREC) { |
| 569 | // We assert that mCache is not null, since there is no |
| 570 | // evaluator running. |
| 571 | ensureCachePrec(MAX_MSD_PREC); |
| 572 | // Could reevaluate more incrementally, but we suspect that if |
| 573 | // we have to reevaluate at all, the result is probably zero. |
| 574 | } |
| 575 | return res; |
| 576 | } |
| 577 | |
| 578 | // Return a string with n placeholder characters. |
| 579 | private String getPadding(int n) { |
| 580 | StringBuilder padding = new StringBuilder(); |
| 581 | char something = |
| 582 | mCalculator.getResources() |
| 583 | .getString(R.string.guessed_digit).charAt(0); |
| 584 | for (int i = 0; i < n; ++i) { |
| 585 | padding.append(something); |
| 586 | } |
| 587 | return padding.toString(); |
| 588 | } |
| 589 | |
| 590 | // Return the number of zero characters at the beginning of s |
| 591 | private int leadingZeroes(String s) { |
| 592 | int res = 0; |
| 593 | int len = s.length(); |
| 594 | for (res = 0; res < len && s.charAt(res) == '0'; ++res) {} |
| 595 | return res; |
| 596 | } |
| 597 | |
Hans Boehm | 08e8f32 | 2015-04-21 13:18:38 -0700 | [diff] [blame] | 598 | private static final int MIN_DIGS = 5; |
| 599 | // Leave at least this many digits from the whole number |
| 600 | // part on the screen, to avoid silly displays like 1E1. |
| 601 | // Return result to exactly prec[0] digits to the right of the |
| 602 | // decimal point. |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 603 | // The result should be no longer than maxDigs. |
Hans Boehm | 08e8f32 | 2015-04-21 13:18:38 -0700 | [diff] [blame] | 604 | // No exponent or other indication of precision is added. |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 605 | // The result is returned immediately, based on the |
| 606 | // current cache contents, but it may contain question |
| 607 | // marks for unknown digits. It may also use uncertain |
| 608 | // digits within EXTRA_DIGITS. If either of those occurred, |
| 609 | // schedule a reevaluation and redisplay operation. |
Hans Boehm | 08e8f32 | 2015-04-21 13:18:38 -0700 | [diff] [blame] | 610 | // Uncertain digits never appear to the left of the decimal point. |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 611 | // digs may be negative to only retrieve digits to the left |
Hans Boehm | 08e8f32 | 2015-04-21 13:18:38 -0700 | [diff] [blame] | 612 | // of the decimal point. (prec[0] = 0 means we include |
| 613 | // the decimal point, but nothing to the right. prec[0] = -1 |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 614 | // means we drop the decimal point and start at the ones |
| 615 | // position. Should not be invoked if mVal is null. |
Hans Boehm | 08e8f32 | 2015-04-21 13:18:38 -0700 | [diff] [blame] | 616 | // This essentially just returns a substring of the full result; |
| 617 | // a leading minus sign or leading digits can be dropped. |
| 618 | // Result uses US conventions; is NOT internationalized. |
| 619 | // We set negative[0] if the number as a whole is negative, |
| 620 | // since we may drop the minus sign. |
| 621 | // We set truncated[0] if leading nonzero digits were dropped. |
| 622 | // getRational() can be used to determine whether the result |
| 623 | // is exact, or whether we dropped trailing digits. |
| 624 | // If the requested prec[0] value is out of range, we update |
| 625 | // it in place and use the updated value. |
| 626 | public String getString(int[] prec, int maxDigs, |
| 627 | boolean[] truncated, boolean[] negative) { |
| 628 | int digs = prec[0]; |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 629 | mLastDigs = digs; |
| 630 | // Make sure we eventually get a complete answer |
| 631 | ensureCachePrec(digs + EXTRA_DIGITS); |
| 632 | if (mCache == null) { |
| 633 | // Nothing to do now; seems to happen on rare occasion |
Hans Boehm | 08e8f32 | 2015-04-21 13:18:38 -0700 | [diff] [blame] | 634 | // with weird user input timing; |
| 635 | // Will repair itself in a jiffy. |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 636 | return getPadding(1); |
| 637 | } |
| 638 | // Compute an appropriate substring of mCache. |
| 639 | // We avoid returning a huge string to minimize string |
| 640 | // allocation during scrolling. |
| 641 | // Pad as needed. |
Hans Boehm | 08e8f32 | 2015-04-21 13:18:38 -0700 | [diff] [blame] | 642 | final int len = mCache.length(); |
| 643 | final boolean myNegative = mCache.charAt(0) == '-'; |
| 644 | negative[0] = myNegative; |
| 645 | // Don't scroll left past leftmost digits in mCache |
| 646 | // unless that still leaves an integer. |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 647 | int integralDigits = len - mCacheDigs; |
| 648 | // includes 1 for dec. pt |
Hans Boehm | 08e8f32 | 2015-04-21 13:18:38 -0700 | [diff] [blame] | 649 | if (myNegative) --integralDigits; |
| 650 | int minDigs = Math.min(-integralDigits + MIN_DIGS, -1); |
| 651 | digs = Math.max(digs, minDigs); |
| 652 | prec[0] = digs; |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 653 | int offset = mCacheDigs - digs; // trailing digits to drop |
| 654 | int deficit = 0; // The number of digits we're short |
| 655 | if (offset < 0) { |
| 656 | offset = 0; |
| 657 | deficit = Math.min(digs - mCacheDigs, maxDigs); |
| 658 | } |
| 659 | int endIndx = len - offset; |
| 660 | if (endIndx < 1) return " "; |
| 661 | int startIndx = (endIndx + deficit <= maxDigs) ? |
| 662 | 0 |
| 663 | : endIndx + deficit - maxDigs; |
Hans Boehm | 08e8f32 | 2015-04-21 13:18:38 -0700 | [diff] [blame] | 664 | truncated[0] = (startIndx > getMsd()); |
| 665 | String res = mCache.substring(startIndx, endIndx); |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 666 | if (deficit > 0) { |
| 667 | res = res + getPadding(deficit); |
| 668 | // Since we always compute past the decimal point, |
| 669 | // this never fills in the spot where the decimal point |
| 670 | // should go, and the rest of this can treat the |
| 671 | // made-up symbols as though they were digits. |
| 672 | } |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 673 | return res; |
| 674 | } |
| 675 | |
Hans Boehm | 4a6b7cb | 2015-04-03 18:41:52 -0700 | [diff] [blame] | 676 | // Return rational representation of current result, if any. |
| 677 | public BoundedRational getRational() { |
| 678 | return mRatVal; |
| 679 | } |
| 680 | |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 681 | private void clearCache() { |
| 682 | mCache = null; |
| 683 | mCacheDigs = mCacheDigsReq = 0; |
| 684 | mMsd = INVALID_MSD; |
| 685 | } |
| 686 | |
| 687 | void clear() { |
| 688 | mExpr.clear(); |
| 689 | clearCache(); |
| 690 | } |
| 691 | |
Hans Boehm | c023b73 | 2015-04-29 11:30:47 -0700 | [diff] [blame] | 692 | // Begin evaluation of result and display when ready. |
| 693 | // We assume this is called after each insertion and deletion. |
| 694 | // Thus if we are called twice with the same effective end of |
| 695 | // the formula, the evaluation is redundant. |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 696 | void evaluateAndShowResult() { |
Hans Boehm | c023b73 | 2015-04-29 11:30:47 -0700 | [diff] [blame] | 697 | if (!mChangedValue) { |
| 698 | // Already done or in progress. |
| 699 | return; |
| 700 | } |
| 701 | cancelAll(); |
| 702 | clearCache(); |
| 703 | mEvaluator = new AsyncDisplayResult(mDegreeMode, false); |
| 704 | mEvaluator.execute(); |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 705 | } |
| 706 | |
| 707 | // Ensure that we either display a result or complain. |
| 708 | // Does not invalidate a previously computed cache. |
Hans Boehm | c023b73 | 2015-04-29 11:30:47 -0700 | [diff] [blame] | 709 | // We presume that any prior result was computed using the same |
| 710 | // expression. |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 711 | void requireResult() { |
Hans Boehm | c023b73 | 2015-04-29 11:30:47 -0700 | [diff] [blame] | 712 | if (mCache == null || mExpr.hasTrailingOperators()) { |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 713 | // Restart evaluator in requested mode, i.e. with |
Hans Boehm | c023b73 | 2015-04-29 11:30:47 -0700 | [diff] [blame] | 714 | // longer timeout, not ignoring trailing operators. |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 715 | cancelAll(); |
Hans Boehm | c023b73 | 2015-04-29 11:30:47 -0700 | [diff] [blame] | 716 | clearCache(); |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 717 | mEvaluator = new AsyncDisplayResult(mDegreeMode, true); |
| 718 | mEvaluator.execute(); |
| 719 | } else { |
Hans Boehm | c023b73 | 2015-04-29 11:30:47 -0700 | [diff] [blame] | 720 | // Notify immediately, reusing existing result. |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 721 | int dotPos = mCache.indexOf('.'); |
| 722 | String truncatedWholePart = mCache.substring(0, dotPos); |
| 723 | mCalculator.onEvaluate(mLastDigs,truncatedWholePart); |
| 724 | } |
| 725 | } |
| 726 | |
| 727 | // Cancel all current background tasks. |
| 728 | // Return true if we cancelled an initial evaluation, |
| 729 | // leaving the expression displayed. |
| 730 | boolean cancelAll() { |
| 731 | if (mCurrentReevaluator != null) { |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 732 | mCurrentReevaluator.cancel(true); |
| 733 | mCacheDigsReq = mCacheDigs; |
| 734 | // Backgound computation touches only constructive reals. |
| 735 | // OK not to wait. |
| 736 | mCurrentReevaluator = null; |
| 737 | } |
| 738 | if (mEvaluator != null) { |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 739 | mEvaluator.cancel(true); |
| 740 | // There seems to be no good way to wait for cancellation |
| 741 | // to complete, and the evaluation continues to look at |
| 742 | // mExpr, which we will again modify. |
| 743 | // Give ourselves a new copy to work on instead. |
| 744 | mExpr = (CalculatorExpr)mExpr.clone(); |
| 745 | // Approximation of constructive reals should be thread-safe, |
| 746 | // so we can let that continue until it notices the cancellation. |
| 747 | mEvaluator = null; |
| 748 | return true; |
| 749 | } |
| 750 | return false; |
| 751 | } |
| 752 | |
| 753 | void restoreInstanceState(DataInput in) { |
| 754 | try { |
| 755 | CalculatorExpr.initExprInput(); |
| 756 | mDegreeMode = in.readBoolean(); |
| 757 | mExpr = new CalculatorExpr(in); |
Hans Boehm | 4a6b7cb | 2015-04-03 18:41:52 -0700 | [diff] [blame] | 758 | mSavedName = in.readUTF(); |
| 759 | mSaved = new CalculatorExpr(in); |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 760 | } catch (IOException e) { |
Hans Boehm | 4a6b7cb | 2015-04-03 18:41:52 -0700 | [diff] [blame] | 761 | Log.v("Calculator", "Exception while restoring:\n" + e); |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 762 | } |
| 763 | } |
| 764 | |
| 765 | void saveInstanceState(DataOutput out) { |
| 766 | try { |
| 767 | CalculatorExpr.initExprOutput(); |
| 768 | out.writeBoolean(mDegreeMode); |
| 769 | mExpr.write(out); |
Hans Boehm | 4a6b7cb | 2015-04-03 18:41:52 -0700 | [diff] [blame] | 770 | out.writeUTF(mSavedName); |
| 771 | mSaved.write(out); |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 772 | } catch (IOException e) { |
Hans Boehm | 4a6b7cb | 2015-04-03 18:41:52 -0700 | [diff] [blame] | 773 | Log.v("Calculator", "Exception while saving state:\n" + e); |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 774 | } |
| 775 | } |
| 776 | |
| 777 | // Append a button press to the current expression. |
Hans Boehm | c023b73 | 2015-04-29 11:30:47 -0700 | [diff] [blame] | 778 | // Return false if we rejected the insertion due to obvious |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 779 | // syntax issues, and the expression is unchanged. |
| 780 | // Return true otherwise. |
| 781 | boolean append(int id) { |
Hans Boehm | c023b73 | 2015-04-29 11:30:47 -0700 | [diff] [blame] | 782 | mChangedValue = (KeyMaps.digVal(id) != KeyMaps.NOT_DIGIT |
| 783 | || KeyMaps.isSuffix(id) |
| 784 | || id == R.id.const_pi || id == R.id.const_e); |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 785 | return mExpr.add(id); |
| 786 | } |
| 787 | |
Hans Boehm | c023b73 | 2015-04-29 11:30:47 -0700 | [diff] [blame] | 788 | void delete() { |
| 789 | mChangedValue = true; |
| 790 | mExpr.delete(); |
| 791 | } |
| 792 | |
Hans Boehm | bfe8c22 | 2015-04-02 16:26:07 -0700 | [diff] [blame] | 793 | void setDegreeMode(boolean degrees) { |
Hans Boehm | c023b73 | 2015-04-29 11:30:47 -0700 | [diff] [blame] | 794 | mChangedValue = true; |
Hans Boehm | bfe8c22 | 2015-04-02 16:26:07 -0700 | [diff] [blame] | 795 | mDegreeMode = degrees; |
Hans Boehm | 682ff5e | 2015-03-09 14:40:25 -0700 | [diff] [blame] | 796 | } |
| 797 | |
Hans Boehm | bfe8c22 | 2015-04-02 16:26:07 -0700 | [diff] [blame] | 798 | boolean getDegreeMode() { |
| 799 | return mDegreeMode; |
Hans Boehm | 682ff5e | 2015-03-09 14:40:25 -0700 | [diff] [blame] | 800 | } |
| 801 | |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 802 | // Abbreviate the current expression to a pre-evaluated |
| 803 | // expression node, which will display as a short number. |
| 804 | // This should not be called unless the expression was |
| 805 | // previously evaluated and produced a non-error result. |
| 806 | // Pre-evaluated expressions can never represent an |
| 807 | // expression for which evaluation to a constructive real |
| 808 | // diverges. Subsequent re-evaluation will also not diverge, |
| 809 | // though it may generate errors of various kinds. |
| 810 | // E.g. sqrt(-10^-1000) |
| 811 | void collapse () { |
Hans Boehm | 682ff5e | 2015-03-09 14:40:25 -0700 | [diff] [blame] | 812 | BigInteger intVal = BoundedRational.asBigInteger(mRatVal); |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 813 | CalculatorExpr abbrvExpr = mExpr.abbreviate( |
Hans Boehm | 682ff5e | 2015-03-09 14:40:25 -0700 | [diff] [blame] | 814 | mVal, mRatVal, mDegreeMode, |
| 815 | getShortString(mCache, intVal)); |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 816 | clear(); |
| 817 | mExpr.append(abbrvExpr); |
| 818 | } |
| 819 | |
Hans Boehm | 4a6b7cb | 2015-04-03 18:41:52 -0700 | [diff] [blame] | 820 | // Same as above, but put result in mSaved, leaving mExpr alone. |
| 821 | // Return false if result is unavailable. |
| 822 | boolean collapseToSaved() { |
| 823 | if (mCache == null) return false; |
| 824 | BigInteger intVal = BoundedRational.asBigInteger(mRatVal); |
| 825 | CalculatorExpr abbrvExpr = mExpr.abbreviate( |
| 826 | mVal, mRatVal, mDegreeMode, |
| 827 | getShortString(mCache, intVal)); |
| 828 | mSaved.clear(); |
| 829 | mSaved.append(abbrvExpr); |
| 830 | return true; |
| 831 | } |
| 832 | |
| 833 | Uri uriForSaved() { |
| 834 | return new Uri.Builder().scheme("tag") |
| 835 | .encodedOpaquePart(mSavedName) |
| 836 | .build(); |
| 837 | } |
| 838 | |
| 839 | // Collapse the current expression to mSaved and return a URI |
| 840 | // describing this particular result, so that we can refer to it |
| 841 | // later. |
| 842 | Uri capture() { |
| 843 | if (!collapseToSaved()) return null; |
| 844 | // Generate a new (entirely private) URI for this result. |
| 845 | // Attempt to conform to RFC4151, though it's unclear it matters. |
| 846 | Date date = new Date(); |
| 847 | TimeZone tz = TimeZone.getDefault(); |
| 848 | DateFormat df = new SimpleDateFormat("yyyy-MM-dd"); |
| 849 | df.setTimeZone(tz); |
| 850 | String isoDate = df.format(new Date()); |
| 851 | mSavedName = "calculator2.android.com," + isoDate + ":" |
| 852 | + (new Random().nextInt() & 0x3fffffff); |
| 853 | Uri tag = uriForSaved(); |
| 854 | return tag; |
| 855 | } |
| 856 | |
| 857 | boolean isLastSaved(Uri uri) { |
| 858 | return uri.equals(uriForSaved()); |
| 859 | } |
| 860 | |
| 861 | void addSaved() { |
Hans Boehm | ed9e678 | 2015-05-01 17:21:13 -0700 | [diff] [blame^] | 862 | mChangedValue = true; |
Hans Boehm | 4a6b7cb | 2015-04-03 18:41:52 -0700 | [diff] [blame] | 863 | mExpr.append(mSaved); |
| 864 | } |
| 865 | |
Hans Boehm | 8461495 | 2014-11-25 18:46:17 -0800 | [diff] [blame] | 866 | // Retrieve the main expression being edited. |
| 867 | // It is the callee's reponsibility to call cancelAll to cancel |
| 868 | // ongoing concurrent computations before modifying the result. |
| 869 | // TODO: Perhaps add functionality so we can keep this private? |
| 870 | CalculatorExpr getExpr() { |
| 871 | return mExpr; |
| 872 | } |
| 873 | |
| 874 | } |