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AbstractReader.d

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00001 /*******************************************************************************
00002 
00003         @file AbstractReader.d
00004         
00005         Copyright (c) 2004 Kris Bell
00006         
00007         This software is provided 'as-is', without any express or implied
00008         warranty. In no event will the authors be held liable for damages
00009         of any kind arising from the use of this software.
00010         
00011         Permission is hereby granted to anyone to use this software for any 
00012         purpose, including commercial applications, and to alter it and/or 
00013         redistribute it freely, subject to the following restrictions:
00014         
00015         1. The origin of this software must not be misrepresented; you must 
00016            not claim that you wrote the original software. If you use this 
00017            software in a product, an acknowledgment within documentation of 
00018            said product would be appreciated but is not required.
00019 
00020         2. Altered source versions must be plainly marked as such, and must 
00021            not be misrepresented as being the original software.
00022 
00023         3. This notice may not be removed or altered from any distribution
00024            of the source.
00025 
00026         4. Derivative works are permitted, but they must carry this notice
00027            in full and credit the original source.
00028 
00029 
00030                         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
00031 
00032 
00033         @version        Initial version, October 2004      
00034         @author         Kris, Ivan Senji (the "alias get" idea)
00035 
00036 
00037 *******************************************************************************/
00038 
00039 module mango.io.AbstractReader;
00040 
00041 private import  mango.io.Exception,
00042                 mango.io.ArrayAllocator;
00043 
00044 public  import  mango.io.model.IReader,
00045                 mango.io.model.IBuffer,
00046                 mango.io.model.IConduit;
00047 
00048 
00049 /*******************************************************************************
00050 
00051         Reader base-class. Each reader operates upon an IBuffer, which is
00052         provided at construction time. Said buffer is intended to remain 
00053         consistent over the reader lifetime.
00054 
00055         All readers support the full set of native data types, plus a full
00056         selection of array types. The latter can be configured to produce
00057         either a copy (.dup) of the buffer content, or a slice. See class
00058         SimpleAllocator, BufferAllocator and SliceAllocator for more on 
00059         this topic.
00060 
00061         Readers support a C++ iostream type syntax, along with Java-esque 
00062         get() notation. However, the Mango style is to place IO elements 
00063         within their own parenthesis, like so:
00064         
00065                 int count;
00066                 char[] verse;
00067 
00068                 read () (count);
00069 
00070         Note that each element is distict; this enables "strong typing", 
00071         which should catch any typo errors at compile-time.
00072 
00073         The code below illustrates basic operation upon a memory buffer:
00074         
00075         @code
00076         Buffer buf = new Buffer (256);
00077 
00078         // map same buffer into both reader and writer
00079         IReader read = new Reader (buf);
00080         IWriter write = new Writer (buf);
00081 
00082         int i = 10;
00083         long j = 20;
00084         double d = 3.14159;
00085         char[] c = "fred";
00086 
00087         // write data types out
00088         write (c) (i) (j) (d);
00089 
00090         // read them back again
00091         read (c) (i) (j) (d);
00092 
00093         // reset
00094         buf.clear();
00095 
00096         // same thing again, but using iostream syntax instead
00097         write << c << i << j << d;
00098 
00099         // read them back again
00100         read >> c >> i >> j >> d;
00101 
00102         // reset
00103         buf.clear();
00104 
00105         // same thing again, but using put() syntax instead
00106         write.put(c).put(i).put(j).put(d);
00107         read.get(c).get(i).get(j).get(d);
00108 
00109         @endcode
00110 
00111         Note that certain Readers, such as the basic binary implementation, 
00112         expect to retrieve the number of array elements from the source. 
00113         For example; when reading an array from a file, the number of elements 
00114         is read from the file also. If the content is not arranged in such a 
00115         manner, you may specify how many elements to read via a second argument:
00116 
00117         @code
00118                 read (myArray, 11);
00119         @endcode
00120 
00121         Readers may also be used with any class implementing the IReadable
00122         interface. See PickleReader for an example of how this can be put
00123         to good use.
00124         
00125 *******************************************************************************/
00126 
00127 class AbstractReader : SimpleAllocator, IReader
00128 {       
00129         alias get opShr;
00130         alias get opCall;
00131           
00132         /***********************************************************************
00133 
00134         ***********************************************************************/
00135 
00136         union Decoder
00137         {
00138                 struct {
00139                        BufferDecoder    int1,
00140                                         int8,
00141                                         int16,
00142                                         int32,
00143                                         int64,
00144                                         int8u,
00145                                         int16u,
00146                                         int32u,
00147                                         int64u,
00148                                         float32,
00149                                         float64,
00150                                         float80,
00151                                         char8,
00152                                         char16,
00153                                         char32;
00154                        }
00155                 BufferDecoder[15]       decoders;
00156         }
00157 
00158         // the buffer associated with this reader. Note that this
00159         // must not change for the lifetime of the reader, since
00160         // it is assumed to be immutable elsewhere (subclass may
00161         // keep its own copy).
00162         protected IBuffer               buffer;         
00163 
00164         // buffer decoders
00165         protected Decoder               decode;
00166 
00167         // memory-manager for array requests
00168         private IArrayAllocator         memory;
00169 
00170         /***********************************************************************
00171         
00172                 Return the buffer associated with this reader
00173 
00174         ***********************************************************************/
00175 
00176         this (IBuffer buffer)
00177         {
00178                 this.buffer = buffer;
00179                 setAllocator (this);
00180         }
00181 
00182         /***********************************************************************
00183         
00184                 Return the buffer associated with this reader
00185 
00186         ***********************************************************************/
00187 
00188         final IBuffer getBuffer ()
00189         {
00190                 return buffer;
00191         }
00192 
00193         /***********************************************************************
00194         
00195                 Return the allocator associated with this reader.See 
00196                 ArrayAllocator for more information.
00197 
00198         ***********************************************************************/
00199 
00200         final IArrayAllocator getAllocator ()
00201         {
00202                 return memory;
00203         }
00204 
00205         /***********************************************************************
00206         
00207                 Set the allocator to use for array management. Arrays are
00208                 always allocated by the IReader. That is, you cannot read
00209                 data into an array slice (for example). Instead, a number
00210                 of IArrayAllocator classes are available to manage memory
00211                 allocation when reading array content. 
00212 
00213                 By default, an IReader will allocate each array from the 
00214                 heap. You can change that behavior by calling this method
00215                 with an IArrayAllocator of choice. For instance, there 
00216                 is a BufferAllocator which will slice an array directly 
00217                 from the buffer where possible. Also available is the 
00218                 record-oriented SliceAllocator, which slices memory from 
00219                 within a pre-allocated heap area, and should be reset by
00220                 the client code after each record has been read (to avoid 
00221                 unnecessary growth).
00222 
00223                 See ArrayAllocator for more information.
00224 
00225         ***********************************************************************/
00226 
00227         final void setAllocator (IArrayAllocator memory) 
00228         {
00229                 memory.bind (this);
00230                 this.memory = memory;
00231         }
00232 
00233         /***********************************************************************
00234         
00235                 Bind an IDecoder to the writer. Decoders are intended to
00236                 be used as a conversion mechanism between various character
00237                 representations (encodings), or the translation of any data
00238                 type from one representation to another. Each data type may
00239                 be configured with a distinct decoder, covering all native
00240                 types (15 in total).
00241 
00242                 An appropriate decoder set should be attached to each 
00243                 IReader, and thus be available for subsequent use. A raw 
00244                 binary implementation is attached by default (no encoding).
00245 
00246                 See module mango.icu.UMango for an example of decoder 
00247                 implementation -- those classes bind the ICU converters 
00248                 to this IO package.
00249 
00250         ***********************************************************************/
00251 
00252         final void setDecoder (IDecoder d) 
00253         {
00254                 decode.decoders[d.type] = d.bind (this);
00255         }
00256 
00257         /***********************************************************************
00258         
00259                 Read and return an integer from the input stream. This is
00260                 used to extract the element count of a subsequent array.
00261 
00262         ***********************************************************************/
00263 
00264         private final uint count (uint elements)
00265         {
00266                 if (elements == uint.max)
00267                     get (elements);
00268                 return elements;
00269         }
00270 
00271         /***********************************************************************
00272         
00273                 Wait for something to arrive in the buffer. This may stall
00274                 the current thread forever, although usage of SocketConduit 
00275                 will take advantage of the timeout facilities provided there.
00276 
00277         ***********************************************************************/
00278 
00279         final void wait ()
00280         {       
00281                 buffer.get (1, false);
00282         }
00283 
00284         /***********************************************************************
00285         
00286                 Extract a readable class from the current read-position
00287                 
00288         ***********************************************************************/
00289 
00290         final IReader get (IReadable x) 
00291         {
00292                 assert (x);
00293                 x.read (this); 
00294                 return this;
00295         }
00296 
00297         /***********************************************************************
00298 
00299                 Extract a boolean value from the current read-position  
00300                 
00301         ***********************************************************************/
00302 
00303         IReader get (inout bool x)
00304         {
00305                 decode.int1 (&x, x.sizeof);
00306                 return this;
00307         }
00308 
00309         /***********************************************************************
00310 
00311                 Extract an unsigned byte value from the current read-position   
00312                                 
00313         ***********************************************************************/
00314 
00315         IReader get (inout ubyte x) 
00316         {       
00317                 decode.int8u (&x, x.sizeof);
00318                 return this;
00319         }
00320 
00321         /***********************************************************************
00322         
00323                 Extract a byte value from the current read-position
00324                 
00325         ***********************************************************************/
00326 
00327         IReader get (inout byte x)
00328         {
00329                 decode.int8 (&x, x.sizeof);
00330                 return this;
00331         }
00332 
00333         /***********************************************************************
00334         
00335                 Extract an unsigned short value from the current read-position
00336                 
00337         ***********************************************************************/
00338 
00339         IReader get (inout ushort x)
00340         {
00341                 decode.int16u (&x, x.sizeof);
00342                 return this;
00343         }
00344 
00345         /***********************************************************************
00346         
00347                 Extract a short value from the current read-position
00348                 
00349         ***********************************************************************/
00350 
00351         IReader get (inout short x)
00352         {
00353                 decode.int16 (&x, x.sizeof);
00354                 return this;
00355         }
00356 
00357         /***********************************************************************
00358         
00359                 Extract a unsigned int value from the current read-position
00360                 
00361         ***********************************************************************/
00362 
00363         IReader get (inout uint x)
00364         {
00365                 decode.int32u (&x, x.sizeof);
00366                 return this;
00367         }
00368 
00369         /***********************************************************************
00370         
00371                 Extract an int value from the current read-position
00372                 
00373         ***********************************************************************/
00374 
00375         IReader get (inout int x)
00376         {
00377                 decode.int32 (&x, x.sizeof);
00378                 return this;
00379         }
00380 
00381         /***********************************************************************
00382         
00383                 Extract an unsigned long value from the current read-position
00384                 
00385         ***********************************************************************/
00386 
00387         IReader get (inout ulong x)
00388         {
00389                 decode.int64u (&x, x.sizeof);
00390                 return this;
00391         }
00392 
00393         /***********************************************************************
00394         
00395                 Extract a long value from the current read-position
00396                 
00397         ***********************************************************************/
00398 
00399         IReader get (inout long x)
00400         {
00401                 decode.int64 (&x, x.sizeof);
00402                 return this;
00403         }
00404 
00405         /***********************************************************************
00406         
00407                 Extract a float value from the current read-position
00408                 
00409         ***********************************************************************/
00410 
00411         IReader get (inout float x)
00412         {
00413                 decode.float32 (&x, x.sizeof);
00414                 return this;
00415         }
00416 
00417         /***********************************************************************
00418         
00419                 Extract a double value from the current read-position
00420                 
00421         ***********************************************************************/
00422 
00423         IReader get (inout double x)
00424         {
00425                 decode.float64 (&x, x.sizeof);
00426                 return this;
00427         }
00428 
00429         /***********************************************************************
00430         
00431                 Extract a real value from the current read-position
00432                 
00433         ***********************************************************************/
00434 
00435         IReader get (inout real x)
00436         {
00437                 decode.float80 (&x, x.sizeof);
00438                 return this;
00439         }
00440 
00441         /***********************************************************************
00442         
00443                 Extract a char value from the current read-position
00444                 
00445         ***********************************************************************/
00446 
00447         IReader get (inout char x)
00448         {
00449                 decode.char8 (&x, x.sizeof);
00450                 return this;
00451         }
00452 
00453         /***********************************************************************
00454         
00455                 Extract a wide char value from the current read-position
00456                 
00457         ***********************************************************************/
00458 
00459         IReader get (inout wchar x)
00460         {
00461                 decode.char16 (&x, x.sizeof);
00462                 return this;
00463         }
00464 
00465         /***********************************************************************
00466         
00467                 Extract a double char value from the current read-position
00468                 
00469         ***********************************************************************/
00470 
00471         IReader get (inout dchar x)
00472         {
00473                 decode.char32 (&x, x.sizeof);
00474                 return this;
00475         }
00476 
00477         /***********************************************************************
00478 
00479                 Extract an unsigned byte value from the current read-position   
00480                                 
00481         ***********************************************************************/
00482 
00483         IReader get (inout ubyte[] x, uint elements = uint.max) 
00484         {
00485                 memory.allocate (cast(void[]*) &x, count(elements), ubyte.sizeof, decode.int8u);
00486                 return this;
00487         }
00488 
00489         /***********************************************************************
00490         
00491                 Extract a byte value from the current read-position
00492                 
00493         ***********************************************************************/
00494 
00495         IReader get (inout byte[] x, uint elements = uint.max)
00496         {
00497                 memory.allocate (cast(void[]*) &x, count(elements), byte.sizeof, decode.int8);
00498                 return this;
00499         }
00500 
00501         /***********************************************************************
00502         
00503                 Extract an unsigned short value from the current read-position
00504                 
00505         ***********************************************************************/
00506 
00507         IReader get (inout ushort[] x, uint elements = uint.max)
00508         {
00509                 memory.allocate (cast(void[]*) &x, count(elements), ushort.sizeof, decode.int16u);
00510                 return this;
00511         }
00512 
00513         /***********************************************************************
00514         
00515                 Extract a short value from the current read-position
00516                 
00517         ***********************************************************************/
00518 
00519         IReader get (inout short[] x, uint elements = uint.max)
00520         {
00521                 memory.allocate (cast(void[]*) &x, count(elements), short.sizeof, decode.int16);
00522                 return this;
00523         }
00524 
00525         /***********************************************************************
00526         
00527                 Extract a unsigned int value from the current read-position
00528                 
00529         ***********************************************************************/
00530 
00531         IReader get (inout uint[] x, uint elements = uint.max)
00532         {
00533                 memory.allocate (cast(void[]*) &x, count(elements), uint.sizeof, decode.int32u);
00534                 return this;
00535         }
00536 
00537         /***********************************************************************
00538         
00539                 Extract an int value from the current read-position
00540                 
00541         ***********************************************************************/
00542 
00543         IReader get (inout int[] x, uint elements = uint.max)
00544         {
00545                 memory.allocate (cast(void[]*) &x, count(elements), int.sizeof, decode.int32);
00546                 return this;
00547         }
00548 
00549         /***********************************************************************
00550         
00551                 Extract an unsigned long value from the current read-position
00552                 
00553         ***********************************************************************/
00554 
00555         IReader get (inout ulong[] x, uint elements = uint.max)
00556         {
00557                 memory.allocate (cast(void[]*) &x, count(elements), ulong.sizeof, decode.int64u);
00558                 return this;
00559         }
00560 
00561         /***********************************************************************
00562         
00563                 Extract a long value from the current read-position
00564                 
00565         ***********************************************************************/
00566 
00567         IReader get (inout long[] x, uint elements = uint.max)
00568         {
00569                 memory.allocate (cast(void[]*) &x, count(elements), long.sizeof, decode.int64);
00570                 return this;
00571         }
00572 
00573         /***********************************************************************
00574         
00575                 Extract a float value from the current read-position
00576                 
00577         ***********************************************************************/
00578 
00579         IReader get (inout float[] x, uint elements = uint.max)
00580         {
00581                 memory.allocate (cast(void[]*) &x, count(elements), float.sizeof, decode.float32);
00582                 return this;
00583         }
00584 
00585         /***********************************************************************
00586         
00587                 Extract a double value from the current read-position
00588                 
00589         ***********************************************************************/
00590 
00591         IReader get (inout double[] x, uint elements = uint.max)
00592         {
00593                 memory.allocate (cast(void[]*) &x, count(elements), double.sizeof, decode.float64);
00594                 return this;
00595         }
00596 
00597         /***********************************************************************
00598         
00599                 Extract a real value from the current read-position
00600                 
00601         ***********************************************************************/
00602 
00603         IReader get (inout real[] x, uint elements = uint.max)
00604         {
00605                 memory.allocate (cast(void[]*) &x, count(elements), real.sizeof, decode.float80);
00606                 return this;
00607         }
00608 
00609         /***********************************************************************
00610         
00611         ***********************************************************************/
00612 
00613         IReader get (inout char[] x, uint elements = uint.max)
00614         {
00615                 memory.allocate (cast(void[]*) &x, count(elements), char.sizeof, decode.char8);
00616                 return this;
00617         }
00618 
00619         /***********************************************************************
00620         
00621         ***********************************************************************/
00622 
00623         IReader get (inout wchar[] x, uint elements = uint.max)
00624         {
00625                 memory.allocate (cast(void[]*) &x, count(elements), wchar.sizeof, decode.char16);
00626                 return this;
00627         }
00628 
00629         /***********************************************************************
00630         
00631         ***********************************************************************/
00632 
00633         IReader get (inout dchar[] x, uint elements = uint.max)
00634         {
00635                 memory.allocate (cast(void[]*) &x, count(elements), dchar.sizeof, decode.char32);
00636                 return this;
00637         }
00638 }
00639 
00640 
00641 /+
00642         /***********************************************************************
00643 
00644         ***********************************************************************/
00645 
00646         template Get (T, alias decoder)
00647         {
00648                 IReader get (inout T x)
00649                 {
00650                         decoder.get (&x, x.sizeof);
00651                         return this;
00652                 }
00653         }
00654 
00655         template GetArray (T, alias decoder)
00656         {
00657                 IReader get (inout T x)
00658                 {
00659                         memory.allocate (cast(void[]*) &x, decoder);
00660                         return this;
00661                 }
00662         }
00663 
00664         mixin Get!(byte, decode.int8);
00665         //mixin GetArray!(byte[], decode.int8);
00666 +/

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