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Reader.d

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00001 /*******************************************************************************
00002 
00003         @file Reader.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 
00027                         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
00028 
00029 
00030         @version        Initial version, March 2004      
00031         @author         Kris
00032 
00033 
00034 *******************************************************************************/
00035 
00036 module mango.io.Reader;
00037 
00038 public import mango.io.AbstractReader;
00039 
00040 /*******************************************************************************
00041 
00042         Binary data Reader. Each reader operates upon an IBuffer, which is
00043         provided at construction time. Said buffer is intended to remain 
00044         consistent over the reader lifetime.
00045 
00046         Readers support both a C++ iostream type syntax, along with a get()
00047         syntax. Operations may be chained back-to-back.
00048 
00049         All readers support the full set of native data types, plus a
00050         selection of array types. The latter can be configured to produce
00051         either a copy (.dup) of the buffer content, or a slice. See class
00052         SimpleAllocator, BufferAllocator and SliceAllocator for more on 
00053         this topic.
00054 
00055         The code below illustrates basic operation upon a memory buffer:
00056         
00057         @code
00058         Buffer buf = new Buffer (256);
00059 
00060         // map same buffer into both reader and writer
00061         IReader r = new Reader(buf);
00062         IWriter w = new Writer(buf);
00063 
00064         int i = 10;
00065         long j = 20;
00066         double d = 3.14159;
00067         char[] c = "fred";
00068 
00069         // write data types out
00070         w << c << i << j << d;
00071 
00072         // read them back again
00073         r >> c >> i >> j >> d;
00074 
00075         // reset
00076         buf.clear();
00077 
00078         // same thing again, but using get() syntax instead
00079         w.put(c).put(i).put(j).put(d);
00080         r.get(c).get(i).get(j).get(d);
00081 
00082         @endcode
00083 
00084         Readers may also be used with any class implementing the IReadable
00085         interface. See PickleReader for an example of how this can be put
00086         to good use.
00087         
00088 *******************************************************************************/
00089 
00090 class Reader : AbstractReader
00091 {       
00092         /***********************************************************************
00093         
00094                 Construct a reader on the provided buffer.
00095 
00096         ***********************************************************************/
00097 
00098         this (IBuffer buffer)
00099         {
00100                 super (buffer);
00101 
00102                 numeric.int1    = 
00103                 numeric.int8    = 
00104                 numeric.int8u   =
00105                 numeric.int16   = 
00106                 numeric.int16u  = 
00107                 numeric.int32   = 
00108                 numeric.int32u  =
00109                 numeric.int64   =
00110                 numeric.int64u  =
00111                 numeric.float32 =
00112                 numeric.float64 =
00113                 numeric.float80 =
00114                 string.char8    = 
00115                 string.char16   = 
00116                 string.char32   = &read;
00117         }
00118 
00119         /***********************************************************************
00120         
00121                 Construct a reader on the buffer belonging to the given
00122                 conduit.
00123 
00124         ***********************************************************************/
00125 
00126         this (IConduit conduit)
00127         {
00128                 this (conduit.createBuffer); 
00129         }
00130        
00131         /***********************************************************************
00132         
00133         ***********************************************************************/
00134         
00135         override char[] toString()
00136         {
00137                 return "binary reader";
00138         }
00139 
00140         /***********************************************************************
00141         
00142         ***********************************************************************/
00143 
00144         final void read (void *dst, uint count)
00145         {
00146                 while (count)
00147                       {
00148                       // get as much as there is available in the buffer
00149                       uint available = buffer.readable();
00150                       
00151                       // cap bytes read
00152                       if (available > count)
00153                           available = count;
00154 
00155                       // copy them over
00156                       dst[0..available] = buffer.get (available);
00157 
00158                       // bump counters
00159                       dst += available;
00160                       count -= available;
00161 
00162                       // if we need more input, get it
00163                       if (count)
00164                           if (! buffer.get(1, false).length)
00165                                 throw (buffer.getConduit) ? eof : udf;
00166                       }
00167         }
00168 }
00169 

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