Mercurial > projects > ldc
annotate tango/tango/io/Buffer.d @ 136:0e28624814e8 trunk
[svn r140] did a lot of the work towards being able to pass multiple modules on the command line. not complete yet though
| author | lindquist |
|---|---|
| date | Thu, 17 Jan 2008 03:15:12 +0100 |
| parents | 1700239cab2e |
| children | ce7b81fb957f |
| rev | line source |
|---|---|
| 132 | 1 /******************************************************************************* |
| 2 | |
| 3 copyright: Copyright (c) 2004 Kris Bell. All rights reserved | |
| 4 | |
| 5 license: BSD style: $(LICENSE) | |
| 6 | |
| 7 version: Mar 2004: Initial release | |
| 8 Dec 2006: Outback release | |
| 9 | |
| 10 authors: Kris | |
| 11 | |
| 12 *******************************************************************************/ | |
| 13 | |
| 14 module tango.io.Buffer; | |
| 15 | |
| 16 private import tango.core.Exception; | |
| 17 | |
| 18 public import tango.io.model.IBuffer, | |
| 19 tango.io.model.IConduit; | |
| 20 | |
| 21 /****************************************************************************** | |
| 22 | |
| 23 ******************************************************************************/ | |
| 24 | |
| 25 extern (C) | |
| 26 { | |
| 27 protected void * memcpy (void *dst, void *src, uint); | |
|
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28 private int printf(char*, ...); |
| 132 | 29 } |
| 30 | |
| 31 /******************************************************************************* | |
| 32 | |
| 33 Buffer is central concept in Tango I/O. Each buffer acts | |
| 34 as a queue (line) where items are removed from the front | |
| 35 and new items are added to the back. Buffers are modeled | |
| 36 by tango.io.model.IBuffer, and a concrete implementation | |
| 37 is provided by this class. | |
| 38 | |
| 39 Buffer can be read from and written to directly, though | |
| 40 various data-converters and filters are often leveraged | |
| 41 to apply structure to what might otherwise be simple raw | |
| 42 data. | |
| 43 | |
| 44 Buffers may also be tokenized by applying an Iterator. | |
| 45 This can be handy when one is dealing with text input, | |
| 46 and/or the content suits a more fluid format than most | |
| 47 typical converters support. Iterator tokens are mapped | |
| 48 directly onto buffer content (sliced), making them quite | |
| 49 efficient in practice. Like other types of buffer client, | |
| 50 multiple iterators can be mapped onto one common buffer | |
| 51 and access will be serialized. | |
| 52 | |
| 53 Buffers are sometimes memory-only, in which case there | |
| 54 is nothing left to do when a client has consumed all the | |
| 55 content. Other buffers are themselves bound to an external | |
| 56 device called a conduit. When this is the case, a consumer | |
| 57 will eventually cause a buffer to reload via its associated | |
| 58 conduit and previous buffer content will be lost. | |
| 59 | |
| 60 A similar approach is applied to clients which populate a | |
| 61 buffer, whereby the content of a full buffer will be flushed | |
| 62 to a bound conduit before continuing. Another variation is | |
| 63 that of a memory-mapped buffer, whereby the buffer content | |
| 64 is mapped directly to virtual memory exposed via the OS. This | |
| 65 can be used to address large files as an array of content. | |
| 66 | |
| 67 Direct buffer manipulation typically involves appending, | |
| 68 as in the following example: | |
| 69 --- | |
| 70 // create a small buffer | |
| 71 auto buf = new Buffer (256); | |
| 72 | |
| 73 auto foo = "to write some D"; | |
| 74 | |
| 75 // append some text directly to it | |
| 76 buf.append ("now is the time for all good men ").append(foo); | |
| 77 --- | |
| 78 | |
| 79 Alternatively, one might use a formatter to append the buffer: | |
| 80 --- | |
| 81 auto output = new FormatOutput (new Buffer(256)); | |
| 82 output.format ("now is the time for {} good men {}", 3, foo); | |
| 83 --- | |
| 84 | |
| 85 A slice() method will return all valid content within a buffer. | |
| 86 GrowBuffer can be used instead, where one wishes to append beyond | |
| 87 a specified limit. | |
| 88 | |
| 89 A common usage of a buffer is in conjunction with a conduit, | |
| 90 such as FileConduit. Each conduit exposes a preferred-size for | |
| 91 its associated buffers, utilized during buffer construction: | |
| 92 --- | |
| 93 auto file = new FileConduit ("file.name"); | |
| 94 auto buf = new Buffer (file); | |
| 95 --- | |
| 96 | |
| 97 However, this is typically hidden by higher level constructors | |
| 98 such as those exposed via the stream wrappers. For example: | |
| 99 --- | |
| 100 auto input = new DataInput (new FileInput("file.name")); | |
| 101 --- | |
| 102 | |
| 103 There is indeed a buffer between the resultant stream and the | |
| 104 file source, but explicit buffer construction is unecessary in | |
| 105 common cases. | |
| 106 | |
| 107 An Iterator is constructed in a similar manner, where you provide | |
| 108 it an input stream to operate upon. There's a variety of iterators | |
| 109 available in the tango.text.stream package, and they are templated | |
| 110 for each of utf8, utf16, and utf32. This example uses a line iterator | |
| 111 to sweep a text file: | |
| 112 --- | |
| 113 auto lines = new LineInput (new FileInput("file.name")); | |
| 114 foreach (line; lines) | |
| 115 Cout(line).newline; | |
| 116 --- | |
| 117 | |
| 118 Buffers are useful for many purposes within Tango, but there | |
| 119 are times when it may be more appropriate to sidestep them. For | |
| 120 such cases, all conduit derivatives (such as FileConduit) support | |
| 121 direct array-based IO via a pair of read() and write() methods. | |
| 122 | |
| 123 *******************************************************************************/ | |
| 124 | |
| 125 class Buffer : IBuffer | |
| 126 { | |
| 127 protected OutputStream sink; // optional data sink | |
| 128 protected InputStream source; // optional data source | |
| 129 protected void[] data; // the raw data buffer | |
| 130 protected uint index; // current read position | |
| 131 protected uint extent; // limit of valid content | |
| 132 protected uint dimension; // maximum extent of content | |
| 133 | |
| 134 | |
| 135 protected static char[] overflow = "output buffer is full"; | |
| 136 protected static char[] underflow = "input buffer is empty"; | |
| 137 protected static char[] eofRead = "end-of-flow whilst reading"; | |
| 138 protected static char[] eofWrite = "end-of-flow whilst writing"; | |
| 139 | |
| 140 /*********************************************************************** | |
| 141 | |
| 142 Ensure the buffer remains valid between method calls | |
| 143 | |
| 144 ***********************************************************************/ | |
| 145 | |
| 146 invariant | |
| 147 { | |
| 148 assert (index <= extent); | |
| 149 assert (extent <= dimension); | |
| 150 } | |
| 151 | |
| 152 /*********************************************************************** | |
| 153 | |
| 154 Construct a buffer | |
| 155 | |
| 156 Params: | |
| 157 conduit = the conduit to buffer | |
| 158 | |
| 159 Remarks: | |
| 160 Construct a Buffer upon the provided conduit. A relevant | |
| 161 buffer size is supplied via the provided conduit. | |
| 162 | |
| 163 ***********************************************************************/ | |
| 164 | |
| 165 this (IConduit conduit) | |
| 166 { | |
|
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167 printf("Buffer.this(%p)\n", conduit); |
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168 assert (conduit !is null); |
| 132 | 169 assert (conduit); |
| 170 | |
| 171 this (conduit.bufferSize); | |
| 172 setConduit (conduit); | |
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173 |
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0e28624814e8
[svn r140] did a lot of the work towards being able to pass multiple modules on the command line. not complete yet though
lindquist
parents:
132
diff
changeset
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174 assert(this !is null); |
| 132 | 175 } |
| 176 | |
| 177 /*********************************************************************** | |
| 178 | |
| 179 Construct a buffer | |
| 180 | |
| 181 Params: | |
| 182 stream = an input stream | |
| 183 capacity = desired buffer capacity | |
| 184 | |
| 185 Remarks: | |
| 186 Construct a Buffer upon the provided input stream. | |
| 187 | |
| 188 ***********************************************************************/ | |
| 189 | |
| 190 this (InputStream stream, uint capacity) | |
| 191 { | |
| 192 this (capacity); | |
| 193 input = stream; | |
| 194 } | |
| 195 | |
| 196 /*********************************************************************** | |
| 197 | |
| 198 Construct a buffer | |
| 199 | |
| 200 Params: | |
| 201 stream = an output stream | |
| 202 capacity = desired buffer capacity | |
| 203 | |
| 204 Remarks: | |
| 205 Construct a Buffer upon the provided output stream. | |
| 206 | |
| 207 ***********************************************************************/ | |
| 208 | |
| 209 this (OutputStream stream, uint capacity) | |
| 210 { | |
| 211 this (capacity); | |
| 212 output = stream; | |
| 213 } | |
| 214 | |
| 215 /*********************************************************************** | |
| 216 | |
| 217 Construct a buffer | |
| 218 | |
| 219 Params: | |
| 220 capacity = the number of bytes to make available | |
| 221 | |
| 222 Remarks: | |
| 223 Construct a Buffer with the specified number of bytes. | |
| 224 | |
| 225 ***********************************************************************/ | |
| 226 | |
| 227 this (uint capacity = 0) | |
| 228 { | |
|
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229 setContent (new ubyte[capacity], 0); |
|
0e28624814e8
[svn r140] did a lot of the work towards being able to pass multiple modules on the command line. not complete yet though
lindquist
parents:
132
diff
changeset
|
230 assert(this !is null); |
| 132 | 231 } |
| 232 | |
| 233 /*********************************************************************** | |
| 234 | |
| 235 Construct a buffer | |
| 236 | |
| 237 Params: | |
| 238 data = the backing array to buffer within | |
| 239 | |
| 240 Remarks: | |
| 241 Prime a buffer with an application-supplied array. All content | |
| 242 is considered valid for reading, and thus there is no writable | |
| 243 space initially available. | |
| 244 | |
| 245 ***********************************************************************/ | |
| 246 | |
| 247 this (void[] data) | |
| 248 { | |
| 249 setContent (data, data.length); | |
| 250 } | |
| 251 | |
| 252 /*********************************************************************** | |
| 253 | |
| 254 Construct a buffer | |
| 255 | |
| 256 Params: | |
| 257 data = the backing array to buffer within | |
| 258 readable = the number of bytes initially made | |
| 259 readable | |
| 260 | |
| 261 Remarks: | |
| 262 Prime buffer with an application-supplied array, and | |
| 263 indicate how much readable data is already there. A | |
| 264 write operation will begin writing immediately after | |
| 265 the existing readable content. | |
| 266 | |
| 267 This is commonly used to attach a Buffer instance to | |
| 268 a local array. | |
| 269 | |
| 270 ***********************************************************************/ | |
| 271 | |
| 272 this (void[] data, uint readable) | |
| 273 { | |
| 274 setContent (data, readable); | |
| 275 } | |
| 276 | |
| 277 /*********************************************************************** | |
| 278 | |
| 279 Attempt to share an upstream Buffer, and create an instance | |
| 280 where there not one available. | |
| 281 | |
| 282 Params: | |
| 283 stream = an input stream | |
| 284 size = a hint of the desired buffer size. Defaults to the | |
| 285 conduit-defined size | |
| 286 | |
| 287 Remarks: | |
| 288 If an upstream Buffer instances is visible, it will be shared. | |
| 289 Otherwise, a new instance is created based upon the bufferSize | |
| 290 exposed by the stream endpoint (conduit). | |
| 291 | |
| 292 ***********************************************************************/ | |
| 293 | |
| 294 static IBuffer share (InputStream stream, uint size=uint.max) | |
| 295 { | |
| 296 auto b = cast(Buffered) stream; | |
| 297 if (b) | |
| 298 return b.buffer; | |
| 299 | |
| 300 if (size is uint.max) | |
| 301 size = stream.conduit.bufferSize; | |
| 302 | |
| 303 return new Buffer (stream, size); | |
| 304 } | |
| 305 | |
| 306 /*********************************************************************** | |
| 307 | |
| 308 Attempt to share an upstream Buffer, and create an instance | |
| 309 where there not one available. | |
| 310 | |
| 311 Params: | |
| 312 stream = an output stream | |
| 313 size = a hint of the desired buffer size. Defaults to the | |
| 314 conduit-defined size | |
| 315 | |
| 316 Remarks: | |
| 317 If an upstream Buffer instances is visible, it will be shared. | |
| 318 Otherwise, a new instance is created based upon the bufferSize | |
| 319 exposed by the stream endpoint (conduit). | |
| 320 | |
| 321 ***********************************************************************/ | |
| 322 | |
| 323 static IBuffer share (OutputStream stream, uint size=uint.max) | |
| 324 { | |
| 325 auto b = cast(Buffered) stream; | |
| 326 if (b) | |
| 327 return b.buffer; | |
| 328 | |
| 329 if (size is uint.max) | |
| 330 size = stream.conduit.bufferSize; | |
| 331 | |
| 332 return new Buffer (stream, size); | |
| 333 } | |
| 334 | |
| 335 /*********************************************************************** | |
| 336 | |
| 337 Reset the buffer content | |
| 338 | |
| 339 Params: | |
| 340 data = the backing array to buffer within. All content | |
| 341 is considered valid | |
| 342 | |
| 343 Returns: | |
| 344 the buffer instance | |
| 345 | |
| 346 Remarks: | |
| 347 Set the backing array with all content readable. Writing | |
| 348 to this will either flush it to an associated conduit, or | |
| 349 raise an Eof condition. Use clear() to reset the content | |
| 350 (make it all writable). | |
| 351 | |
| 352 ***********************************************************************/ | |
| 353 | |
| 354 IBuffer setContent (void[] data) | |
| 355 { | |
| 356 return setContent (data, data.length); | |
| 357 } | |
| 358 | |
| 359 /*********************************************************************** | |
| 360 | |
| 361 Reset the buffer content | |
| 362 | |
| 363 Params: | |
| 364 data = the backing array to buffer within | |
| 365 readable = the number of bytes within data considered | |
| 366 valid | |
| 367 | |
| 368 Returns: | |
| 369 the buffer instance | |
| 370 | |
| 371 Remarks: | |
| 372 Set the backing array with some content readable. Writing | |
| 373 to this will either flush it to an associated conduit, or | |
| 374 raise an Eof condition. Use clear() to reset the content | |
| 375 (make it all writable). | |
| 376 | |
| 377 ***********************************************************************/ | |
| 378 | |
| 379 IBuffer setContent (void[] data, uint readable) | |
| 380 { | |
| 381 this.data = data; | |
| 382 this.extent = readable; | |
| 383 this.dimension = data.length; | |
| 384 | |
| 385 // reset to start of input | |
| 386 this.index = 0; | |
| 387 | |
| 388 return this; | |
| 389 } | |
| 390 | |
| 391 /*********************************************************************** | |
| 392 | |
| 393 Access buffer content | |
| 394 | |
| 395 Params: | |
| 396 size = number of bytes to access | |
| 397 eat = whether to consume the content or not | |
| 398 | |
| 399 Returns: | |
| 400 the corresponding buffer slice when successful, or | |
| 401 null if there's not enough data available (Eof; Eob). | |
| 402 | |
| 403 Remarks: | |
| 404 Read a slice of data from the buffer, loading from the | |
| 405 conduit as necessary. The specified number of bytes is | |
| 406 sliced from the buffer, and marked as having been read | |
| 407 when the 'eat' parameter is set true. When 'eat' is set | |
| 408 false, the read position is not adjusted. | |
| 409 | |
| 410 Note that the slice cannot be larger than the size of | |
| 411 the buffer ~ use method fill(void[]) instead where you | |
| 412 simply want the content copied, or use conduit.read() | |
| 413 to extract directly from an attached conduit. Also note | |
| 414 that if you need to retain the slice, then it should be | |
| 415 .dup'd before the buffer is compressed or repopulated. | |
| 416 | |
| 417 Examples: | |
| 418 --- | |
| 419 // create a buffer with some content | |
| 420 auto buffer = new Buffer ("hello world"); | |
| 421 | |
| 422 // consume everything unread | |
| 423 auto slice = buffer.slice (buffer.readable); | |
| 424 --- | |
| 425 | |
| 426 ***********************************************************************/ | |
| 427 | |
| 428 void[] slice (uint size, bool eat = true) | |
| 429 { | |
| 430 if (size > readable) | |
| 431 { | |
| 432 if (source is null) | |
| 433 error (underflow); | |
| 434 | |
| 435 // make some space? This will try to leave as much content | |
| 436 // in the buffer as possible, such that entire records may | |
| 437 // be aliased directly from within. | |
| 438 if (size > writable) | |
| 439 { | |
| 440 if (size > dimension) | |
| 441 error (underflow); | |
| 442 compress (); | |
| 443 } | |
| 444 | |
| 445 // populate tail of buffer with new content | |
| 446 do { | |
| 447 if (fill(source) is IConduit.Eof) | |
| 448 error (eofRead); | |
| 449 } while (size > readable); | |
| 450 } | |
| 451 | |
| 452 auto i = index; | |
| 453 if (eat) | |
| 454 index += size; | |
| 455 return data [i .. i + size]; | |
| 456 } | |
| 457 | |
| 458 /********************************************************************** | |
| 459 | |
| 460 Fill the provided buffer. Returns the number of bytes | |
| 461 actually read, which will be less that dst.length when | |
| 462 Eof has been reached and IConduit.Eof thereafter | |
| 463 | |
| 464 **********************************************************************/ | |
| 465 | |
| 466 uint fill (void[] dst) | |
| 467 { | |
| 468 uint len = 0; | |
| 469 | |
| 470 while (len < dst.length) | |
| 471 { | |
| 472 uint i = read (dst [len .. $]); | |
| 473 if (i is IConduit.Eof) | |
| 474 return (len > 0) ? len : IConduit.Eof; | |
| 475 len += i; | |
| 476 } | |
| 477 return len; | |
| 478 } | |
| 479 | |
| 480 /*********************************************************************** | |
| 481 | |
| 482 Copy buffer content into the provided dst | |
| 483 | |
| 484 Params: | |
| 485 dst = destination of the content | |
| 486 bytes = size of dst | |
| 487 | |
| 488 Returns: | |
| 489 A reference to the populated content | |
| 490 | |
| 491 Remarks: | |
| 492 Fill the provided array with content. We try to satisfy | |
| 493 the request from the buffer content, and read directly | |
| 494 from an attached conduit where more is required. | |
| 495 | |
| 496 ***********************************************************************/ | |
| 497 | |
| 498 void[] readExact (void* dst, uint bytes) | |
| 499 { | |
| 500 auto tmp = dst [0 .. bytes]; | |
| 501 if (fill (tmp) != bytes) | |
| 502 error (eofRead); | |
| 503 | |
| 504 return tmp; | |
| 505 } | |
| 506 | |
| 507 /*********************************************************************** | |
| 508 | |
| 509 Append content | |
| 510 | |
| 511 Params: | |
| 512 src = the content to _append | |
| 513 | |
| 514 Returns a chaining reference if all content was written. | |
| 515 Throws an IOException indicating eof or eob if not. | |
| 516 | |
| 517 Remarks: | |
| 518 Append an array to this buffer, and flush to the | |
| 519 conduit as necessary. This is often used in lieu of | |
| 520 a Writer. | |
| 521 | |
| 522 ***********************************************************************/ | |
| 523 | |
| 524 IBuffer append (void[] src) | |
| 525 { | |
| 526 return append (src.ptr, src.length); | |
| 527 } | |
| 528 | |
| 529 /*********************************************************************** | |
| 530 | |
| 531 Append content | |
| 532 | |
| 533 Params: | |
| 534 src = the content to _append | |
| 535 length = the number of bytes in src | |
| 536 | |
| 537 Returns a chaining reference if all content was written. | |
| 538 Throws an IOException indicating eof or eob if not. | |
| 539 | |
| 540 Remarks: | |
| 541 Append an array to this buffer, and flush to the | |
| 542 conduit as necessary. This is often used in lieu of | |
| 543 a Writer. | |
| 544 | |
| 545 ***********************************************************************/ | |
| 546 | |
| 547 IBuffer append (void* src, uint length) | |
| 548 { | |
| 549 if (length > writable) | |
| 550 // can we write externally? | |
| 551 if (sink) | |
| 552 { | |
| 553 flush (); | |
| 554 | |
| 555 // check for pathological case | |
| 556 if (length > dimension) | |
| 557 { | |
| 558 do { | |
| 559 auto written = sink.write (src [0 .. length]); | |
| 560 if (written is IConduit.Eof) | |
| 561 error (eofWrite); | |
| 562 src += written, length -= written; | |
| 563 } while (length > dimension); | |
| 564 } | |
| 565 } | |
| 566 else | |
| 567 error (overflow); | |
| 568 | |
| 569 copy (src, length); | |
| 570 return this; | |
| 571 } | |
| 572 | |
| 573 /*********************************************************************** | |
| 574 | |
| 575 Append content | |
| 576 | |
| 577 Params: | |
| 578 other = a buffer with content available | |
| 579 | |
| 580 Returns: | |
| 581 Returns a chaining reference if all content was written. | |
| 582 Throws an IOException indicating eof or eob if not. | |
| 583 | |
| 584 Remarks: | |
| 585 Append another buffer to this one, and flush to the | |
| 586 conduit as necessary. This is often used in lieu of | |
| 587 a Writer. | |
| 588 | |
| 589 ***********************************************************************/ | |
| 590 | |
| 591 IBuffer append (IBuffer other) | |
| 592 { | |
| 593 return append (other.slice); | |
| 594 } | |
| 595 | |
| 596 /*********************************************************************** | |
| 597 | |
| 598 Consume content from a producer | |
| 599 | |
| 600 Params: | |
| 601 The content to consume. This is consumed verbatim, and in | |
| 602 raw binary format ~ no implicit conversions are performed. | |
| 603 | |
| 604 Remarks: | |
| 605 This is often used in lieu of a Writer, and enables simple | |
| 606 classes, such as FilePath and Uri, to emit content directly | |
| 607 into a buffer (thus avoiding potential heap activity) | |
| 608 | |
| 609 Examples: | |
| 610 --- | |
| 611 auto path = new FilePath (somepath); | |
| 612 | |
| 613 path.produce (&buffer.consume); | |
| 614 --- | |
| 615 | |
| 616 ***********************************************************************/ | |
| 617 | |
| 618 void consume (void[] x) | |
| 619 { | |
| 620 append (x); | |
| 621 } | |
| 622 | |
| 623 /*********************************************************************** | |
| 624 | |
| 625 Retrieve the valid content | |
| 626 | |
| 627 Returns: | |
| 628 a void[] slice of the buffer | |
| 629 | |
| 630 Remarks: | |
| 631 Return a void[] slice of the buffer, from the current position | |
| 632 up to the limit of valid content. The content remains in the | |
| 633 buffer for future extraction. | |
| 634 | |
| 635 ***********************************************************************/ | |
| 636 | |
| 637 void[] slice () | |
| 638 { | |
| 639 return data [index .. extent]; | |
| 640 } | |
| 641 | |
| 642 /*********************************************************************** | |
| 643 | |
| 644 Move the current read location | |
| 645 | |
| 646 Params: | |
| 647 size = the number of bytes to move | |
| 648 | |
| 649 Returns: | |
| 650 Returns true if successful, false otherwise. | |
| 651 | |
| 652 Remarks: | |
| 653 Skip ahead by the specified number of bytes, streaming from | |
| 654 the associated conduit as necessary. | |
| 655 | |
| 656 Can also reverse the read position by 'size' bytes, when size | |
| 657 is negative. This may be used to support lookahead operations. | |
| 658 Note that a negative size will fail where there is not sufficient | |
| 659 content available in the buffer (can't _skip beyond the beginning). | |
| 660 | |
| 661 ***********************************************************************/ | |
| 662 | |
| 663 bool skip (int size) | |
| 664 { | |
| 665 if (size < 0) | |
| 666 { | |
| 667 size = -size; | |
| 668 if (index >= size) | |
| 669 { | |
| 670 index -= size; | |
| 671 return true; | |
| 672 } | |
| 673 return false; | |
| 674 } | |
| 675 return slice(size) !is null; | |
| 676 } | |
| 677 | |
| 678 /*********************************************************************** | |
| 679 | |
| 680 Iterator support | |
| 681 | |
| 682 Params: | |
| 683 scan = the delagate to invoke with the current content | |
| 684 | |
| 685 Returns: | |
| 686 Returns true if a token was isolated, false otherwise. | |
| 687 | |
| 688 Remarks: | |
| 689 Upon success, the delegate should return the byte-based | |
| 690 index of the consumed pattern (tail end of it). Failure | |
| 691 to match a pattern should be indicated by returning an | |
| 692 IConduit.Eof | |
| 693 | |
| 694 Each pattern is expected to be stripped of the delimiter. | |
| 695 An end-of-file condition causes trailing content to be | |
| 696 placed into the token. Requests made beyond Eof result | |
| 697 in empty matches (length is zero). | |
| 698 | |
| 699 Note that additional iterator and/or reader instances | |
| 700 will operate in lockstep when bound to a common buffer. | |
| 701 | |
| 702 ***********************************************************************/ | |
| 703 | |
| 704 bool next (uint delegate (void[]) scan) | |
| 705 { | |
| 706 while (read(scan) is IConduit.Eof) | |
| 707 // not found - are we streaming? | |
| 708 if (source) | |
| 709 { | |
| 710 // did we start at the beginning? | |
| 711 if (position) | |
| 712 // nope - move partial token to start of buffer | |
| 713 compress (); | |
| 714 else | |
| 715 // no more space in the buffer? | |
| 716 if (writable is 0) | |
| 717 error ("Token is too large to fit within buffer"); | |
| 718 | |
| 719 // read another chunk of data | |
| 720 if (fill(source) is IConduit.Eof) | |
| 721 return false; | |
| 722 } | |
| 723 else | |
| 724 return false; | |
| 725 | |
| 726 return true; | |
| 727 } | |
| 728 | |
| 729 /*********************************************************************** | |
| 730 | |
| 731 Available content | |
| 732 | |
| 733 Remarks: | |
| 734 Return count of _readable bytes remaining in buffer. This is | |
| 735 calculated simply as limit() - position() | |
| 736 | |
| 737 ***********************************************************************/ | |
| 738 | |
| 739 uint readable () | |
| 740 { | |
| 741 return extent - index; | |
| 742 } | |
| 743 | |
| 744 /*********************************************************************** | |
| 745 | |
| 746 Available space | |
| 747 | |
| 748 Remarks: | |
| 749 Return count of _writable bytes available in buffer. This is | |
| 750 calculated simply as capacity() - limit() | |
| 751 | |
| 752 ***********************************************************************/ | |
| 753 | |
| 754 uint writable () | |
| 755 { | |
| 756 return dimension - extent; | |
| 757 } | |
| 758 | |
| 759 /*********************************************************************** | |
| 760 | |
| 761 Write into this buffer | |
| 762 | |
| 763 Params: | |
| 764 dg = the callback to provide buffer access to | |
| 765 | |
| 766 Returns: | |
| 767 Returns whatever the delegate returns. | |
| 768 | |
| 769 Remarks: | |
| 770 Exposes the raw data buffer at the current _write position, | |
| 771 The delegate is provided with a void[] representing space | |
| 772 available within the buffer at the current _write position. | |
| 773 | |
| 774 The delegate should return the appropriate number of bytes | |
| 775 if it writes valid content, or IConduit.Eof on error. | |
| 776 | |
| 777 ***********************************************************************/ | |
| 778 | |
| 779 uint write (uint delegate (void[]) dg) | |
| 780 { | |
| 781 int count = dg (data [extent..dimension]); | |
| 782 | |
| 783 if (count != IConduit.Eof) | |
| 784 { | |
| 785 extent += count; | |
| 786 assert (extent <= dimension); | |
| 787 } | |
| 788 return count; | |
| 789 } | |
| 790 | |
| 791 /*********************************************************************** | |
| 792 | |
| 793 Read directly from this buffer | |
| 794 | |
| 795 Params: | |
| 796 dg = callback to provide buffer access to | |
| 797 | |
| 798 Returns: | |
| 799 Returns whatever the delegate returns. | |
| 800 | |
| 801 Remarks: | |
| 802 Exposes the raw data buffer at the current _read position. The | |
| 803 delegate is provided with a void[] representing the available | |
| 804 data, and should return zero to leave the current _read position | |
| 805 intact. | |
| 806 | |
| 807 If the delegate consumes data, it should return the number of | |
| 808 bytes consumed; or IConduit.Eof to indicate an error. | |
| 809 | |
| 810 ***********************************************************************/ | |
| 811 | |
| 812 uint read (uint delegate (void[]) dg) | |
| 813 { | |
| 814 int count = dg (data [index..extent]); | |
| 815 | |
| 816 if (count != IConduit.Eof) | |
| 817 { | |
| 818 index += count; | |
| 819 assert (index <= extent); | |
| 820 } | |
| 821 return count; | |
| 822 } | |
| 823 | |
| 824 /*********************************************************************** | |
| 825 | |
| 826 Compress buffer space | |
| 827 | |
| 828 Returns: | |
| 829 the buffer instance | |
| 830 | |
| 831 Remarks: | |
| 832 If we have some data left after an export, move it to | |
| 833 front-of-buffer and set position to be just after the | |
| 834 remains. This is for supporting certain conduits which | |
| 835 choose to write just the initial portion of a request. | |
| 836 | |
| 837 Limit is set to the amount of data remaining. Position | |
| 838 is always reset to zero. | |
| 839 | |
| 840 ***********************************************************************/ | |
| 841 | |
| 842 IBuffer compress () | |
| 843 { | |
| 844 uint r = readable (); | |
| 845 | |
| 846 if (index > 0 && r > 0) | |
| 847 // content may overlap ... | |
| 848 memcpy (&data[0], &data[index], r); | |
| 849 | |
| 850 index = 0; | |
| 851 extent = r; | |
| 852 return this; | |
| 853 } | |
| 854 | |
| 855 /*********************************************************************** | |
| 856 | |
| 857 Fill buffer from the specific conduit | |
| 858 | |
| 859 Returns: | |
| 860 Returns the number of bytes read, or Conduit.Eof | |
| 861 | |
| 862 Remarks: | |
| 863 Try to _fill the available buffer with content from the | |
| 864 specified conduit. We try to read as much as possible | |
| 865 by clearing the buffer when all current content has been | |
| 866 eaten. If there is no space available, nothing will be | |
| 867 read. | |
| 868 | |
| 869 ***********************************************************************/ | |
| 870 | |
| 871 uint fill (InputStream src) | |
| 872 { | |
| 873 if (src is null) | |
| 874 return IConduit.Eof; | |
| 875 | |
| 876 if (readable is 0) | |
| 877 index = extent = 0; // same as clear(), but without chain | |
| 878 else | |
| 879 if (writable is 0) | |
| 880 return 0; | |
| 881 | |
| 882 return write (&src.read); | |
| 883 } | |
| 884 | |
| 885 /*********************************************************************** | |
| 886 | |
| 887 Drain buffer content to the specific conduit | |
| 888 | |
| 889 Returns: | |
| 890 Returns the number of bytes written | |
| 891 | |
| 892 Remarks: | |
| 893 Write as much of the buffer that the associated conduit | |
| 894 can consume. The conduit is not obliged to consume all | |
| 895 content, so some may remain within the buffer. | |
| 896 | |
| 897 Throws an IOException on premature Eof. | |
| 898 | |
| 899 ***********************************************************************/ | |
| 900 | |
| 901 final uint drain (OutputStream dst) | |
| 902 { | |
| 903 if (dst is null) | |
| 904 return IConduit.Eof; | |
| 905 | |
| 906 uint ret = read (&dst.write); | |
| 907 if (ret is IConduit.Eof) | |
| 908 error (eofWrite); | |
| 909 | |
| 910 compress (); | |
| 911 return ret; | |
| 912 } | |
| 913 | |
| 914 /*********************************************************************** | |
| 915 | |
| 916 Truncate buffer content | |
| 917 | |
| 918 Remarks: | |
| 919 Truncate the buffer within its extent. Returns true if | |
| 920 the new length is valid, false otherwise. | |
| 921 | |
| 922 ***********************************************************************/ | |
| 923 | |
| 924 bool truncate (uint length) | |
| 925 { | |
| 926 if (length <= data.length) | |
| 927 { | |
| 928 extent = length; | |
| 929 return true; | |
| 930 } | |
| 931 return false; | |
| 932 } | |
| 933 | |
| 934 /*********************************************************************** | |
| 935 | |
| 936 Access buffer limit | |
| 937 | |
| 938 Returns: | |
| 939 Returns the limit of readable content within this buffer. | |
| 940 | |
| 941 Remarks: | |
| 942 Each buffer has a capacity, a limit, and a position. The | |
| 943 capacity is the maximum content a buffer can contain, limit | |
| 944 represents the extent of valid content, and position marks | |
| 945 the current read location. | |
| 946 | |
| 947 ***********************************************************************/ | |
| 948 | |
| 949 uint limit () | |
| 950 { | |
| 951 return extent; | |
| 952 } | |
| 953 | |
| 954 /*********************************************************************** | |
| 955 | |
| 956 Access buffer capacity | |
| 957 | |
| 958 Returns: | |
| 959 Returns the maximum capacity of this buffer | |
| 960 | |
| 961 Remarks: | |
| 962 Each buffer has a capacity, a limit, and a position. The | |
| 963 capacity is the maximum content a buffer can contain, limit | |
| 964 represents the extent of valid content, and position marks | |
| 965 the current read location. | |
| 966 | |
| 967 ***********************************************************************/ | |
| 968 | |
| 969 uint capacity () | |
| 970 { | |
| 971 return dimension; | |
| 972 } | |
| 973 | |
| 974 /*********************************************************************** | |
| 975 | |
| 976 Access buffer read position | |
| 977 | |
| 978 Returns: | |
| 979 Returns the current read-position within this buffer | |
| 980 | |
| 981 Remarks: | |
| 982 Each buffer has a capacity, a limit, and a position. The | |
| 983 capacity is the maximum content a buffer can contain, limit | |
| 984 represents the extent of valid content, and position marks | |
| 985 the current read location. | |
| 986 | |
| 987 ***********************************************************************/ | |
| 988 | |
| 989 uint position () | |
| 990 { | |
| 991 return index; | |
| 992 } | |
| 993 | |
| 994 /*********************************************************************** | |
| 995 | |
| 996 Set external conduit | |
| 997 | |
| 998 Params: | |
| 999 conduit = the conduit to attach to | |
| 1000 | |
| 1001 Remarks: | |
| 1002 Sets the external conduit associated with this buffer. | |
| 1003 | |
| 1004 Buffers do not require an external conduit to operate, but | |
| 1005 it can be convenient to associate one. For example, methods | |
| 1006 fill() & drain() use it to import/export content as necessary. | |
| 1007 | |
| 1008 ***********************************************************************/ | |
| 1009 | |
| 1010 IBuffer setConduit (IConduit conduit) | |
| 1011 { | |
| 1012 sink = conduit.output; | |
| 1013 source = conduit.input; | |
| 1014 return this; | |
| 1015 } | |
| 1016 | |
| 1017 /*********************************************************************** | |
| 1018 | |
| 1019 Set output stream | |
| 1020 | |
| 1021 Params: | |
| 1022 sink = the stream to attach to | |
| 1023 | |
| 1024 Remarks: | |
| 1025 Sets the external output stream associated with this buffer. | |
| 1026 | |
| 1027 Buffers do not require an external stream to operate, but | |
| 1028 it can be convenient to associate one. For example, methods | |
| 1029 fill & drain use them to import/export content as necessary. | |
| 1030 | |
| 1031 ***********************************************************************/ | |
| 1032 | |
| 1033 final IBuffer output (OutputStream sink) | |
| 1034 { | |
| 1035 this.sink = sink; | |
| 1036 return this; | |
| 1037 } | |
| 1038 | |
| 1039 /*********************************************************************** | |
| 1040 | |
| 1041 Set input stream | |
| 1042 | |
| 1043 Params: | |
| 1044 source = the stream to attach to | |
| 1045 | |
| 1046 Remarks: | |
| 1047 Sets the external input stream associated with this buffer. | |
| 1048 | |
| 1049 Buffers do not require an external stream to operate, but | |
| 1050 it can be convenient to associate one. For example, methods | |
| 1051 fill & drain use them to import/export content as necessary. | |
| 1052 | |
| 1053 ***********************************************************************/ | |
| 1054 | |
| 1055 final IBuffer input (InputStream source) | |
| 1056 { | |
| 1057 this.source = source; | |
| 1058 return this; | |
| 1059 } | |
| 1060 | |
| 1061 /*********************************************************************** | |
| 1062 | |
| 1063 Access buffer content | |
| 1064 | |
| 1065 Remarks: | |
| 1066 Return the entire backing array. Exposed for subclass usage | |
| 1067 only | |
| 1068 | |
| 1069 ***********************************************************************/ | |
| 1070 | |
| 1071 protected void[] getContent () | |
| 1072 { | |
| 1073 return data; | |
| 1074 } | |
| 1075 | |
| 1076 /*********************************************************************** | |
| 1077 | |
| 1078 Copy content into buffer | |
| 1079 | |
| 1080 Params: | |
| 1081 src = the soure of the content | |
| 1082 size = the length of content at src | |
| 1083 | |
| 1084 Remarks: | |
| 1085 Bulk _copy of data from 'src'. The new content is made | |
| 1086 available for reading. This is exposed for subclass use | |
| 1087 only | |
| 1088 | |
| 1089 ***********************************************************************/ | |
| 1090 | |
| 1091 protected void copy (void *src, uint size) | |
| 1092 { | |
| 1093 // avoid "out of bounds" test on zero size | |
| 1094 if (size) | |
| 1095 { | |
| 1096 // content may overlap ... | |
| 1097 memcpy (&data[extent], src, size); | |
| 1098 extent += size; | |
| 1099 } | |
| 1100 } | |
| 1101 | |
| 1102 /*********************************************************************** | |
| 1103 | |
| 1104 Cast to a target type without invoking the wrath of the | |
| 1105 runtime checks for misalignment. Instead, we truncate the | |
| 1106 array length | |
| 1107 | |
| 1108 ***********************************************************************/ | |
| 1109 | |
| 1110 static T[] convert(T)(void[] x) | |
| 1111 { | |
| 1112 return (cast(T*) x.ptr) [0 .. (x.length / T.sizeof)]; | |
| 1113 } | |
| 1114 | |
| 1115 | |
| 1116 | |
| 1117 /**********************************************************************/ | |
| 1118 /*********************** Buffered Interface ***************************/ | |
| 1119 /**********************************************************************/ | |
| 1120 | |
| 1121 IBuffer buffer () | |
| 1122 { | |
| 1123 return this; | |
| 1124 } | |
| 1125 | |
| 1126 | |
| 1127 /**********************************************************************/ | |
| 1128 /******************** Stream & Conduit Interfaces *********************/ | |
| 1129 /**********************************************************************/ | |
| 1130 | |
| 1131 | |
| 1132 /*********************************************************************** | |
| 1133 | |
| 1134 Return the name of this conduit | |
| 1135 | |
| 1136 ***********************************************************************/ | |
| 1137 | |
| 1138 override char[] toString () | |
| 1139 { | |
| 1140 return "<buffer>"; | |
| 1141 } | |
| 1142 | |
| 1143 /*********************************************************************** | |
| 1144 | |
| 1145 Generic IOException thrower | |
| 1146 | |
| 1147 Params: | |
| 1148 msg = a text message describing the exception reason | |
| 1149 | |
| 1150 Remarks: | |
| 1151 Throw an IOException with the provided message | |
| 1152 | |
| 1153 ***********************************************************************/ | |
| 1154 | |
| 1155 final void error (char[] msg) | |
| 1156 { | |
| 1157 throw new IOException (msg); | |
| 1158 } | |
| 1159 | |
| 1160 /*********************************************************************** | |
| 1161 | |
| 1162 Flush all buffer content to the specific conduit | |
| 1163 | |
| 1164 Remarks: | |
| 1165 Flush the contents of this buffer. This will block until | |
| 1166 all content is actually flushed via the associated conduit, | |
| 1167 whereas drain() will not. | |
| 1168 | |
| 1169 Do nothing where a conduit is not attached, enabling memory | |
| 1170 buffers to treat flush as a noop. | |
| 1171 | |
| 1172 Throws an IOException on premature Eof. | |
| 1173 | |
| 1174 ***********************************************************************/ | |
| 1175 | |
| 1176 override OutputStream flush () | |
| 1177 { | |
| 1178 if (sink) | |
| 1179 { | |
| 1180 while (readable() > 0) | |
| 1181 drain (sink); | |
| 1182 | |
| 1183 // flush the filter chain also | |
| 1184 sink.flush; | |
| 1185 } | |
| 1186 return this; | |
| 1187 } | |
| 1188 | |
| 1189 /*********************************************************************** | |
| 1190 | |
| 1191 Clear buffer content | |
| 1192 | |
| 1193 Remarks: | |
| 1194 Reset 'position' and 'limit' to zero. This effectively | |
| 1195 clears all content from the buffer. | |
| 1196 | |
| 1197 ***********************************************************************/ | |
| 1198 | |
| 1199 override InputStream clear () | |
| 1200 { | |
| 1201 index = extent = 0; | |
| 1202 | |
| 1203 // clear the filter chain also | |
| 1204 if (source) | |
| 1205 source.clear; | |
| 1206 return this; | |
| 1207 } | |
| 1208 | |
| 1209 /*********************************************************************** | |
| 1210 | |
| 1211 Copy content via this buffer from the provided src | |
| 1212 conduit. | |
| 1213 | |
| 1214 Remarks: | |
| 1215 The src conduit has its content transferred through | |
| 1216 this buffer via a series of fill & drain operations, | |
| 1217 until there is no more content available. The buffer | |
| 1218 content should be explicitly flushed by the caller. | |
| 1219 | |
| 1220 Throws an IOException on premature eof | |
| 1221 | |
| 1222 ***********************************************************************/ | |
| 1223 | |
| 1224 override OutputStream copy (InputStream src) | |
| 1225 { | |
| 1226 while (fill(src) != IConduit.Eof) | |
| 1227 // don't drain until we actually need to | |
| 1228 if (writable is 0) | |
| 1229 if (sink) | |
| 1230 drain (sink); | |
| 1231 else | |
| 1232 error (overflow); | |
| 1233 return this; | |
| 1234 } | |
| 1235 | |
| 1236 /*********************************************************************** | |
| 1237 | |
| 1238 Transfer content into the provided dst | |
| 1239 | |
| 1240 Params: | |
| 1241 dst = destination of the content | |
| 1242 | |
| 1243 Returns: | |
| 1244 return the number of bytes read, which may be less than | |
| 1245 dst.length. Eof is returned when no further content is | |
| 1246 available. | |
| 1247 | |
| 1248 Remarks: | |
| 1249 Populates the provided array with content. We try to | |
| 1250 satisfy the request from the buffer content, and read | |
| 1251 directly from an attached conduit when the buffer is | |
| 1252 empty. | |
| 1253 | |
| 1254 ***********************************************************************/ | |
| 1255 | |
| 1256 override uint read (void[] dst) | |
| 1257 { | |
| 1258 uint content = readable(); | |
| 1259 if (content) | |
| 1260 { | |
| 1261 if (content >= dst.length) | |
| 1262 content = dst.length; | |
| 1263 | |
| 1264 // transfer buffer content | |
| 1265 dst [0 .. content] = data [index .. index + content]; | |
| 1266 index += content; | |
| 1267 } | |
| 1268 else | |
| 1269 if (source) | |
| 1270 { | |
| 1271 // pathological cases read directly from conduit | |
| 1272 if (dst.length > dimension) | |
| 1273 content = source.read (dst); | |
| 1274 else | |
| 1275 // keep buffer partially populated | |
| 1276 if ((content = fill(source)) != IConduit.Eof && content > 0) | |
| 1277 content = read (dst); | |
| 1278 } | |
| 1279 else | |
| 1280 content = IConduit.Eof; | |
| 1281 return content; | |
| 1282 } | |
| 1283 | |
| 1284 /*********************************************************************** | |
| 1285 | |
| 1286 Emulate OutputStream.write() | |
| 1287 | |
| 1288 Params: | |
| 1289 src = the content to write | |
| 1290 | |
| 1291 Returns: | |
| 1292 return the number of bytes written, which may be less than | |
| 1293 provided (conceptually). | |
| 1294 | |
| 1295 Remarks: | |
| 1296 Appends src content to the buffer, flushing to an attached | |
| 1297 conduit as necessary. An IOException is thrown upon write | |
| 1298 failure. | |
| 1299 | |
| 1300 ***********************************************************************/ | |
| 1301 | |
| 1302 override uint write (void[] src) | |
| 1303 { | |
| 1304 append (src.ptr, src.length); | |
| 1305 return src.length; | |
| 1306 } | |
| 1307 | |
| 1308 /*********************************************************************** | |
| 1309 | |
| 1310 Access configured conduit | |
| 1311 | |
| 1312 Returns: | |
| 1313 Returns the conduit associated with this buffer. Returns | |
| 1314 null if the buffer is purely memory based; that is, it's | |
| 1315 not backed by some external medium. | |
| 1316 | |
| 1317 Remarks: | |
| 1318 Buffers do not require an external conduit to operate, but | |
| 1319 it can be convenient to associate one. For example, methods | |
| 1320 fill() & drain() use it to import/export content as necessary. | |
| 1321 | |
| 1322 ***********************************************************************/ | |
| 1323 | |
| 1324 final override IConduit conduit () | |
| 1325 { | |
| 1326 if (sink) | |
| 1327 return sink.conduit; | |
| 1328 else | |
| 1329 if (source) | |
| 1330 return source.conduit; | |
| 1331 return this; | |
| 1332 } | |
| 1333 | |
| 1334 /*********************************************************************** | |
| 1335 | |
| 1336 Return a preferred size for buffering conduit I/O | |
| 1337 | |
| 1338 ***********************************************************************/ | |
| 1339 | |
| 1340 final override uint bufferSize () | |
| 1341 { | |
| 1342 return 32 * 1024; | |
| 1343 } | |
| 1344 | |
| 1345 /*********************************************************************** | |
| 1346 | |
| 1347 Is the conduit alive? | |
| 1348 | |
| 1349 ***********************************************************************/ | |
| 1350 | |
| 1351 final override bool isAlive () | |
| 1352 { | |
| 1353 return true; | |
| 1354 } | |
| 1355 | |
| 1356 /*********************************************************************** | |
| 1357 | |
| 1358 Exposes configured output stream | |
| 1359 | |
| 1360 Returns: | |
| 1361 Returns the OutputStream associated with this buffer. Returns | |
| 1362 null if the buffer is not attached to an output; that is, it's | |
| 1363 not backed by some external medium. | |
| 1364 | |
| 1365 Remarks: | |
| 1366 Buffers do not require an external stream to operate, but | |
| 1367 it can be convenient to associate them. For example, methods | |
| 1368 fill & drain use them to import/export content as necessary. | |
| 1369 | |
| 1370 ***********************************************************************/ | |
| 1371 | |
| 1372 final OutputStream output () | |
| 1373 { | |
| 1374 return sink; | |
| 1375 } | |
| 1376 | |
| 1377 /*********************************************************************** | |
| 1378 | |
| 1379 Exposes configured input stream | |
| 1380 | |
| 1381 Returns: | |
| 1382 Returns the InputStream associated with this buffer. Returns | |
| 1383 null if the buffer is not attached to an input; that is, it's | |
| 1384 not backed by some external medium. | |
| 1385 | |
| 1386 Remarks: | |
| 1387 Buffers do not require an external stream to operate, but | |
| 1388 it can be convenient to associate them. For example, methods | |
| 1389 fill & drain use them to import/export content as necessary. | |
| 1390 | |
| 1391 ***********************************************************************/ | |
| 1392 | |
| 1393 final InputStream input () | |
| 1394 { | |
| 1395 return source; | |
| 1396 } | |
| 1397 | |
| 1398 /*********************************************************************** | |
| 1399 | |
| 1400 Release external resources | |
| 1401 | |
| 1402 ***********************************************************************/ | |
| 1403 | |
| 1404 final override void detach () | |
| 1405 { | |
| 1406 } | |
| 1407 | |
| 1408 /*********************************************************************** | |
| 1409 | |
| 1410 Close the stream | |
| 1411 | |
| 1412 Remarks: | |
| 1413 Propagate request to an attached OutputStream (this is a | |
| 1414 requirement for the OutputStream interface) | |
| 1415 | |
| 1416 ***********************************************************************/ | |
| 1417 | |
| 1418 override void close () | |
| 1419 { | |
| 1420 if (sink) | |
| 1421 sink.close; | |
| 1422 else | |
| 1423 if (source) | |
| 1424 source.close; | |
| 1425 } | |
| 1426 } |