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8eabb4ff MW |
1 | /* -*-scala-*- |
2 | * | |
3 | * Miscellaneous utilities | |
4 | * | |
5 | * (c) 2018 Straylight/Edgeware | |
6 | */ | |
7 | ||
8 | /*----- Licensing notice --------------------------------------------------* | |
9 | * | |
10 | * This file is part of the Trivial IP Encryption (TrIPE) Android app. | |
11 | * | |
12 | * TrIPE is free software: you can redistribute it and/or modify it under | |
13 | * the terms of the GNU General Public License as published by the Free | |
14 | * Software Foundation; either version 3 of the License, or (at your | |
15 | * option) any later version. | |
16 | * | |
17 | * TrIPE is distributed in the hope that it will be useful, but WITHOUT | |
18 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
19 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
20 | * for more details. | |
21 | * | |
22 | * You should have received a copy of the GNU General Public License | |
23 | * along with TrIPE. If not, see <https://www.gnu.org/licenses/>. | |
24 | */ | |
25 | ||
26 | package uk.org.distorted; package object tripe { | |
27 | ||
28 | /*----- Imports -----------------------------------------------------------*/ | |
29 | ||
30 | import scala.concurrent.duration.{Deadline, Duration}; | |
c8292b34 | 31 | import scala.util.control.{Breaks, ControlThrowable}; |
8eabb4ff | 32 | |
c8292b34 | 33 | import java.io.{BufferedReader, Closeable, File, InputStream, Reader}; |
04a5abae | 34 | import java.net.{HttpURLConnection, URL, URLConnection}; |
8eabb4ff | 35 | import java.nio.{ByteBuffer, CharBuffer}; |
04a5abae MW |
36 | import java.nio.channels.{SelectionKey, Selector}; |
37 | import java.nio.channels.spi.{AbstractSelector, AbstractSelectableChannel}; | |
8eabb4ff | 38 | import java.nio.charset.Charset; |
04a5abae | 39 | import java.util.{Set => JSet}; |
8eabb4ff MW |
40 | import java.util.concurrent.locks.{Lock, ReentrantLock}; |
41 | ||
42 | /*----- Miscellaneous useful things ---------------------------------------*/ | |
43 | ||
44 | val rng = new java.security.SecureRandom; | |
45 | ||
46 | def unreachable(msg: String): Nothing = throw new AssertionError(msg); | |
c8292b34 MW |
47 | def unreachable(): Nothing = unreachable("unreachable"); |
48 | final val ok = (); | |
49 | final class Brand; | |
8eabb4ff MW |
50 | |
51 | /*----- Various pieces of implicit magic ----------------------------------*/ | |
52 | ||
53 | class InvalidCStringException(msg: String) extends Exception(msg); | |
8eabb4ff | 54 | |
25c35469 | 55 | object Implicits { |
8eabb4ff MW |
56 | |
57 | /* --- Syntactic sugar for locks --- */ | |
58 | ||
59 | implicit class LockOps(lk: Lock) { | |
60 | /* LK withLock { BODY } | |
61 | * LK.withLock(INTERRUPT) { BODY } | |
25c35469 MW |
62 | * LK.withLock(DUR, [INTERRUPT]) { BODY } orElse { ALT } |
63 | * LK.withLock(DL, [INTERRUPT]) { BODY } orElse { ALT } | |
8eabb4ff MW |
64 | * |
65 | * Acquire a lock while executing a BODY. If a duration or deadline is | |
66 | * given then wait so long for the lock, and then give up and run ALT | |
67 | * instead. | |
68 | */ | |
69 | ||
70 | def withLock[T](dur: Duration, interrupt: Boolean) | |
71 | (body: => T): PendingLock[T] = | |
72 | new PendingLock(lk, if (dur > Duration.Zero) dur else Duration.Zero, | |
73 | interrupt, body); | |
74 | def withLock[T](dur: Duration)(body: => T): PendingLock[T] = | |
75 | withLock(dur, true)(body); | |
76 | def withLock[T](dl: Deadline, interrupt: Boolean) | |
77 | (body: => T): PendingLock[T] = | |
78 | new PendingLock(lk, dl.timeLeft, interrupt, body); | |
79 | def withLock[T](dl: Deadline)(body: => T): PendingLock[T] = | |
80 | withLock(dl, true)(body); | |
81 | def withLock[T](interrupt: Boolean)(body: => T): T = { | |
82 | if (interrupt) lk.lockInterruptibly(); | |
83 | else lk.lock(); | |
84 | try { body; } finally lk.unlock(); | |
85 | } | |
86 | def withLock[T](body: => T): T = withLock(true)(body); | |
87 | } | |
88 | ||
25c35469 | 89 | class PendingLock[T] private[Implicits] |
8eabb4ff MW |
90 | (val lk: Lock, val dur: Duration, |
91 | val interrupt: Boolean, body: => T) { | |
25c35469 | 92 | /* An auxiliary class for LockOps; provides the `orElse' qualifier. */ |
8eabb4ff | 93 | |
25c35469 | 94 | def orElse(alt: => T): T = { |
8eabb4ff MW |
95 | val locked = (dur, interrupt) match { |
96 | case (Duration.Inf, true) => lk.lockInterruptibly(); true | |
97 | case (Duration.Inf, false) => lk.lock(); true | |
98 | case (Duration.Zero, false) => lk.tryLock() | |
99 | case (_, true) => lk.tryLock(dur.length, dur.unit) | |
100 | case _ => unreachable("timed wait is always interruptible"); | |
101 | } | |
102 | if (!locked) alt; | |
103 | else try { body; } finally lk.unlock(); | |
104 | } | |
105 | } | |
8eabb4ff MW |
106 | } |
107 | ||
108 | /*----- Cleanup assistant -------------------------------------------------*/ | |
109 | ||
110 | class Cleaner { | |
111 | /* A helper class for avoiding deep nests of `try'/`finally'. | |
112 | * | |
113 | * Make a `Cleaner' instance CL at the start of your operation. Apply it | |
114 | * to blocks of code -- as CL { ACTION } -- as you proceed, to accumulate | |
115 | * cleanup actions. Finally, call CL.cleanup() to invoke the accumulated | |
116 | * actions, in reverse order. | |
117 | */ | |
118 | ||
119 | var cleanups: List[() => Unit] = Nil; | |
120 | def apply(cleanup: => Unit) { cleanups +:= { () => cleanup; } } | |
121 | def cleanup() { cleanups foreach { _() } } | |
122 | } | |
123 | ||
124 | def withCleaner[T](body: Cleaner => T): T = { | |
125 | /* An easier way to use the `Cleaner' class. Just | |
126 | * | |
127 | * withCleaner { CL => BODY } | |
128 | * | |
129 | * The BODY can attach cleanup actions to the cleaner CL by saying | |
130 | * CL { ACTION } as usual. When the BODY exits, normally or otherwise, the | |
131 | * cleanup actions are invoked in reverse order. | |
132 | */ | |
133 | ||
134 | val cleaner = new Cleaner; | |
135 | try { body(cleaner) } | |
136 | finally { cleaner.cleanup(); } | |
137 | } | |
138 | ||
139 | def closing[T, U <: Closeable](thing: U)(body: U => T): T = | |
140 | try { body(thing) } | |
141 | finally { thing.close(); } | |
142 | ||
c8292b34 MW |
143 | /*----- Control structures ------------------------------------------------*/ |
144 | ||
145 | private case class ExitBlock[T](brand: Brand, result: T) | |
146 | extends ControlThrowable; | |
147 | ||
148 | def block[T](body: (T => Nothing) => T): T = { | |
149 | /* block { exit[T] => ...; exit(x); ... } | |
150 | * | |
151 | * Execute the body until it calls the `exit' function or finishes. | |
152 | * Annoyingly, Scala isn't clever enough to infer the return type, so | |
153 | * you'll have to write it explicitly. | |
154 | */ | |
155 | ||
156 | val mybrand = new Brand; | |
157 | try { body { result => throw new ExitBlock(mybrand, result) } } | |
158 | catch { | |
159 | case ExitBlock(brand, result) if brand eq mybrand => | |
160 | result.asInstanceOf[T] | |
161 | } | |
162 | } | |
163 | ||
164 | def blockUnit(body: (=> Nothing) => Unit) { | |
165 | /* blockUnit { exit => ...; exit; ... } | |
166 | * | |
167 | * Like `block'; it just saves you having to write `exit[Unit] => ...; | |
168 | * exit(ok); ...'. | |
169 | */ | |
170 | ||
171 | val mybrand = new Brand; | |
172 | try { body { throw new ExitBlock(mybrand, null) }; } | |
173 | catch { case ExitBlock(brand, result) if brand eq mybrand => ok; } | |
174 | } | |
175 | ||
176 | def loop[T](body: (T => Nothing) => Unit): T = { | |
177 | /* loop { exit[T] => ...; exit(x); ... } | |
178 | * | |
179 | * Repeatedly execute the body until it calls the `exit' function. | |
180 | * Annoyingly, Scala isn't clever enough to infer the return type, so | |
181 | * you'll have to write it explicitly. | |
182 | */ | |
183 | ||
184 | block { exit => while (true) body(exit); unreachable } | |
185 | } | |
186 | ||
187 | def loopUnit(body: (=> Nothing) => Unit): Unit = { | |
188 | /* loopUnit { exit => ...; exit; ... } | |
189 | * | |
190 | * Like `loop'; it just saves you having to write `exit[Unit] => ...; | |
191 | * exit(()); ...'. | |
192 | */ | |
193 | ||
194 | blockUnit { exit => while (true) body(exit); } | |
195 | } | |
196 | ||
197 | val BREAKS = new Breaks; | |
198 | import BREAKS.{breakable, break}; | |
199 | ||
04a5abae MW |
200 | /*----- Interruptably doing things ----------------------------------------*/ |
201 | ||
202 | private class InterruptCatcher[T](body: => T, onWakeup: => Unit) | |
203 | extends AbstractSelector(null) { | |
204 | /* Hook onto the VM's thread interruption machinery. | |
205 | * | |
206 | * The `run' method is the only really interesting one. It will run the | |
207 | * BODY, returning its result; if the thread is interrupted during this | |
208 | * time, ONWAKEUP is invoked for effect. The expectation is that ONWAKEUP | |
209 | * will somehow cause BODY to stop early. | |
210 | * | |
211 | * Credit for this hack goes to Nicholas Wilson: see | |
212 | * <https://github.com/NWilson/javaInterruptHook>. | |
213 | */ | |
214 | ||
215 | private def nope: Nothing = | |
216 | { throw new UnsupportedOperationException("can't do that"); } | |
217 | protected def implCloseSelector() { } | |
218 | protected def register(chan: AbstractSelectableChannel, | |
219 | ops: Int, att: Any): SelectionKey = nope; | |
220 | def keys(): JSet[SelectionKey] = nope; | |
221 | def selectedKeys(): JSet[SelectionKey] = nope; | |
222 | def select(): Int = nope; | |
223 | def select(millis: Long): Int = nope; | |
224 | def selectNow(): Int = nope; | |
225 | ||
226 | def run(): T = try { | |
227 | begin(); | |
228 | val ret = body; | |
229 | if (Thread.interrupted()) throw new InterruptedException; | |
230 | ret | |
231 | } finally { | |
232 | end(); | |
233 | } | |
234 | def wakeup(): Selector = { onWakeup; this } | |
235 | } | |
236 | ||
237 | class PendingInterruptable[T] private[tripe](body: => T) { | |
238 | /* This class exists to provide the `onInterrupt THUNK' syntax. */ | |
239 | ||
240 | def onInterrupt(thunk: => Unit): T = | |
241 | new InterruptCatcher(body, thunk).run(); | |
242 | } | |
243 | def interruptably[T](body: => T) = { | |
244 | /* interruptably { BODY } onInterrupt { THUNK } | |
245 | * | |
246 | * Execute BODY and return its result. If the thread receives an | |
247 | * interrupt -- or is already in an interrupted state -- execute THUNK for | |
248 | * effect; it is expected to cause BODY to return expeditiously, and when | |
249 | * the BODY completes, an `InterruptedException' is thrown. | |
250 | */ | |
251 | ||
252 | new PendingInterruptable(body); | |
253 | } | |
254 | ||
8eabb4ff MW |
255 | /*----- A gadget for fetching URLs ----------------------------------------*/ |
256 | ||
257 | class URLFetchException(msg: String) extends Exception(msg); | |
258 | ||
259 | trait URLFetchCallbacks { | |
260 | def preflight(conn: URLConnection) { } | |
c8292b34 | 261 | def write(buf: Array[Byte], n: Int, len: Long): Unit; |
8eabb4ff MW |
262 | def done(win: Boolean) { } |
263 | } | |
264 | ||
265 | def fetchURL(url: URL, cb: URLFetchCallbacks) { | |
266 | /* Fetch the URL, feeding the data through the callbacks CB. */ | |
267 | ||
268 | withCleaner { clean => | |
04a5abae | 269 | var win: Boolean = false; clean { cb.done(win); } |
8eabb4ff | 270 | |
04a5abae MW |
271 | /* Set up the connection. This isn't going to block, I think, and we |
272 | * need to use it in the interrupt handler. | |
273 | */ | |
8eabb4ff | 274 | val c = url.openConnection(); |
8eabb4ff | 275 | |
04a5abae MW |
276 | /* Java's default URL handlers don't respond to interrupts, so we have to |
277 | * take over this duty. | |
8eabb4ff | 278 | */ |
04a5abae MW |
279 | interruptably { |
280 | /* Run the caller's preflight check. This must be done here, since it | |
281 | * might well block while it discovers things like the content length. | |
282 | */ | |
283 | cb.preflight(c); | |
284 | ||
285 | /* Start fetching data. */ | |
286 | val in = c.getInputStream; clean { in.close(); } | |
287 | val explen = c.getContentLength; | |
288 | ||
289 | /* Read a buffer at a time, and give it to the callback. Maintain a | |
290 | * running total. | |
291 | */ | |
292 | var len: Long = 0; | |
293 | blockUnit { exit => | |
294 | for ((buf, n) <- blocks(in)) { | |
295 | cb.write(buf, n, len); | |
296 | len += n; | |
297 | if (explen != -1 && len > explen) exit; | |
298 | } | |
c8292b34 | 299 | } |
8eabb4ff | 300 | |
04a5abae MW |
301 | /* I can't find it documented anywhere that the existing machinery |
302 | * checks the received stream against the advertised content length. | |
303 | * It doesn't hurt to check again, anyway. | |
304 | */ | |
305 | if (explen != -1 && explen != len) { | |
306 | throw new URLFetchException( | |
307 | s"received $len /= $explen bytes from `$url'"); | |
308 | } | |
8eabb4ff | 309 | |
04a5abae MW |
310 | /* Glorious success is ours. */ |
311 | win = true; | |
312 | } onInterrupt { | |
313 | /* Oh. How do we do this? */ | |
314 | ||
315 | c match { | |
316 | case c: HttpURLConnection => | |
317 | /* It's an HTTP connection (what happened to the case here?). | |
318 | * HTTPS connections match too because they're a subclass. Getting | |
319 | * the input stream will block, but there's an easier way. | |
320 | */ | |
321 | c.disconnect(); | |
322 | ||
323 | case _ => | |
324 | /* It's something else. Let's hope that getting the input stream | |
325 | * doesn't block. | |
326 | */ | |
327 | c.getInputStream.close(); | |
328 | } | |
329 | } | |
8eabb4ff MW |
330 | } |
331 | } | |
332 | ||
8eabb4ff MW |
333 | /*----- Threading things --------------------------------------------------*/ |
334 | ||
04a5abae MW |
335 | def thread(name: String, run: Boolean = true, daemon: Boolean = true) |
336 | (f: => Unit): Thread = { | |
8eabb4ff MW |
337 | /* Make a thread with a given name, and maybe start running it. */ |
338 | ||
339 | val t = new Thread(new Runnable { def run() { f; } }, name); | |
340 | if (daemon) t.setDaemon(true); | |
341 | if (run) t.start(); | |
342 | t | |
343 | } | |
344 | ||
04a5abae MW |
345 | class ValueThread[T](name: String, group: ThreadGroup = null, |
346 | stacksz: Long = 0)(body: => T) | |
347 | extends Thread(group, null, name, stacksz) { | |
348 | private[this] var exc: Throwable = _; | |
349 | private[this] var ret: T = _; | |
350 | ||
351 | override def run() { | |
352 | try { ret = body; } | |
353 | catch { case e: Throwable => exc = e; } | |
354 | } | |
355 | def get: T = | |
356 | if (isAlive) throw new IllegalArgumentException("still running"); | |
357 | else if (exc != null) throw exc; | |
358 | else ret; | |
359 | } | |
360 | def valueThread[T](name: String, run: Boolean = true) | |
361 | (body: => T): ValueThread[T] = { | |
362 | val t = new ValueThread(name)(body); | |
363 | if (run) t.start(); | |
364 | t | |
365 | } | |
366 | ||
8eabb4ff MW |
367 | /*----- Quoting and parsing tokens ----------------------------------------*/ |
368 | ||
369 | def quoteTokens(v: Seq[String]): String = { | |
370 | /* Return a string representing the token sequence V. | |
371 | * | |
372 | * The tokens are quoted as necessary. | |
373 | */ | |
374 | ||
375 | val b = new StringBuilder; | |
376 | var sep = false; | |
377 | for (s <- v) { | |
378 | ||
379 | /* If this isn't the first word, then write a separating space. */ | |
380 | if (!sep) sep = true; | |
381 | else b += ' '; | |
382 | ||
383 | /* Decide how to handle this token. */ | |
384 | if (s.length > 0 && | |
385 | (s forall { ch => (ch != ''' && ch != '"' && ch != '\\' && | |
386 | !ch.isWhitespace) })) { | |
387 | /* If this word is nonempty and contains no problematic characters, | |
388 | * we can write it literally. | |
389 | */ | |
390 | ||
391 | b ++= s; | |
392 | } else { | |
393 | /* Otherwise, we shall have to do this the hard way. We could be | |
394 | * cleverer about this, but it's not worth the effort. | |
395 | */ | |
396 | ||
397 | b += '"'; | |
398 | s foreach { ch => | |
399 | if (ch == '"' || ch == '\\') b += '\\'; | |
400 | b += ch; | |
401 | } | |
402 | b += '"'; | |
403 | } | |
404 | } | |
405 | b.result | |
406 | } | |
407 | ||
408 | class InvalidQuotingException(msg: String) extends Exception(msg); | |
409 | ||
410 | def nextToken(s: String, pos: Int = 0): Option[(String, Int)] = { | |
411 | /* Parse the next token from a string S. | |
412 | * | |
413 | * If there is a token in S starting at or after index POS, then return | |
414 | * it, and the index for the following token; otherwise return `None'. | |
415 | */ | |
416 | ||
417 | val b = new StringBuilder; | |
418 | val n = s.length; | |
419 | var i = pos; | |
420 | var q = 0; | |
421 | ||
422 | /* Skip whitespace while we find the next token. */ | |
423 | while (i < n && s(i).isWhitespace) i += 1; | |
424 | ||
425 | /* Maybe there just isn't anything to find. */ | |
426 | if (i >= n) return None; | |
427 | ||
428 | /* There is something there. Unpick the quoting and escaping. */ | |
429 | while (i < n && (q != 0 || !s(i).isWhitespace)) { | |
430 | s(i) match { | |
431 | case '\\' => | |
432 | if (i + 1 >= n) throw new InvalidQuotingException("trailing `\\'"); | |
433 | b += s(i + 1); i += 2; | |
434 | case ch@('"' | ''') => | |
435 | if (q == 0) q = ch; | |
436 | else if (q == ch) q = 0; | |
437 | else b += ch; | |
438 | i += 1; | |
439 | case ch => | |
440 | b += ch; | |
441 | i += 1; | |
442 | } | |
443 | } | |
444 | ||
445 | /* Check that the quoting was valid. */ | |
446 | if (q != 0) throw new InvalidQuotingException(s"unmatched `$q'"); | |
447 | ||
448 | /* Skip whitespace before the next token. */ | |
449 | while (i < n && s(i).isWhitespace) i += 1; | |
450 | ||
451 | /* We're done. */ | |
452 | Some((b.result, i)) | |
453 | } | |
454 | ||
455 | def splitTokens(s: String, pos: Int = 0): Seq[String] = { | |
456 | /* Return all of the tokens in string S into tokens, starting at POS. */ | |
457 | ||
458 | val b = List.newBuilder[String]; | |
459 | var i = pos; | |
460 | ||
c8292b34 MW |
461 | loopUnit { exit => nextToken(s, i) match { |
462 | case Some((w, j)) => b += w; i = j; | |
463 | case None => exit; | |
464 | } } | |
8eabb4ff MW |
465 | b.result |
466 | } | |
467 | ||
c8292b34 MW |
468 | /*----- Other random things -----------------------------------------------*/ |
469 | ||
8eabb4ff | 470 | trait LookaheadIterator[T] extends BufferedIterator[T] { |
c8292b34 MW |
471 | /* An iterator in terms of a single `maybe there's another item' function. |
472 | * | |
473 | * It seems like every time I write an iterator in Scala, the only way to | |
474 | * find out whether there's a next item, for `hasNext', is to actually try | |
475 | * to fetch it. So here's an iterator in terms of a function which goes | |
476 | * off and maybe returns a next thing. It turns out to be easy to satisfy | |
477 | * the additional requirements for `BufferedIterator', so why not? | |
478 | */ | |
479 | ||
480 | /* Subclass responsibility. */ | |
8eabb4ff | 481 | protected def fetch(): Option[T]; |
c8292b34 MW |
482 | |
483 | /* The machinery. `st' is `None' if there's no current item, null if we've | |
484 | * actually hit the end, or `Some(x)' if the current item is x. | |
485 | */ | |
486 | private[this] var st: Option[T] = None; | |
8eabb4ff | 487 | private[this] def peek() { |
c8292b34 | 488 | /* Arrange to have a current item. */ |
8eabb4ff MW |
489 | if (st == None) fetch() match { |
490 | case None => st = null; | |
491 | case x@Some(_) => st = x; | |
492 | } | |
493 | } | |
c8292b34 MW |
494 | |
495 | /* The `BufferedIterator' protocol. */ | |
8eabb4ff | 496 | override def hasNext: Boolean = { peek(); st != null } |
c8292b34 | 497 | override def head: T = |
8eabb4ff | 498 | { peek(); if (st == null) throw new NoSuchElementException; st.get } |
c8292b34 | 499 | override def next(): T = { val it = head; st = None; it } |
8eabb4ff MW |
500 | } |
501 | ||
c8292b34 MW |
502 | def bufferedReader(r: Reader): BufferedReader = r match { |
503 | case br: BufferedReader => br | |
504 | case _ => new BufferedReader(r) | |
505 | } | |
8eabb4ff | 506 | |
c8292b34 MW |
507 | def lines(r: BufferedReader): BufferedIterator[String] = |
508 | new LookaheadIterator[String] { | |
509 | /* Iterates over the lines of text in a `Reader' object. */ | |
510 | override protected def fetch() = Option(r.readLine()); | |
511 | } | |
512 | def lines(r: Reader): BufferedIterator[String] = lines(bufferedReader(r)); | |
513 | ||
514 | def blocks(in: InputStream, blksz: Int): | |
515 | BufferedIterator[(Array[Byte], Int)] = | |
516 | /* Iterates over (possibly irregularly sized) blocks in a stream. */ | |
517 | new LookaheadIterator[(Array[Byte], Int)] { | |
518 | val buf = new Array[Byte](blksz) | |
519 | override protected def fetch() = { | |
520 | val n = in.read(buf); | |
521 | if (n < 0) None | |
522 | else Some((buf, n)) | |
523 | } | |
524 | } | |
525 | def blocks(in: InputStream): | |
04a5abae | 526 | BufferedIterator[(Array[Byte], Int)] = blocks(in, 65536); |
c8292b34 MW |
527 | |
528 | def blocks(in: BufferedReader, blksz: Int): | |
529 | BufferedIterator[(Array[Char], Int)] = | |
530 | /* Iterates over (possibly irregularly sized) blocks in a reader. */ | |
531 | new LookaheadIterator[(Array[Char], Int)] { | |
532 | val buf = new Array[Char](blksz) | |
533 | override protected def fetch() = { | |
534 | val n = in.read(buf); | |
535 | if (n < 0) None | |
536 | else Some((buf, n)) | |
537 | } | |
8eabb4ff | 538 | } |
c8292b34 | 539 | def blocks(in: BufferedReader): |
04a5abae | 540 | BufferedIterator[(Array[Char], Int)] = blocks(in, 65536); |
c8292b34 MW |
541 | def blocks(r: Reader, blksz: Int): BufferedIterator[(Array[Char], Int)] = |
542 | blocks(bufferedReader(r), blksz); | |
543 | def blocks(r: Reader): BufferedIterator[(Array[Char], Int)] = | |
544 | blocks(bufferedReader(r)); | |
545 | ||
546 | def oxford(conj: String, things: Seq[String]): String = things match { | |
547 | case Seq() => "<nothing>" | |
548 | case Seq(a) => a | |
549 | case Seq(a, b) => s"$a $conj $b" | |
550 | case Seq(a, tail@_*) => | |
551 | val sb = new StringBuilder; | |
552 | sb ++= a; sb ++= ", "; | |
553 | def iter(rest: Seq[String]) { | |
554 | rest match { | |
555 | case Seq() => unreachable; | |
556 | case Seq(a) => sb ++= conj; sb += ' '; sb ++= a; | |
557 | case Seq(a, tail@_*) => sb ++= a; sb ++= ", "; iter(tail); | |
558 | } | |
559 | } | |
560 | iter(tail); | |
561 | sb.result | |
8eabb4ff MW |
562 | } |
563 | ||
04a5abae MW |
564 | def formatTime(t: Int): String = |
565 | if (t < -1) "???" | |
566 | else { | |
567 | val (s, t1) = (t%60, t/60); | |
568 | val (m, h) = (t1%60, t1/60); | |
569 | if (h > 0) f"$h%d:$m%02d:$s%02d" | |
570 | else f"$m%02d:$s%02d" | |
571 | } | |
572 | ||
8eabb4ff MW |
573 | /*----- That's all, folks -------------------------------------------------*/ |
574 | ||
575 | } |