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TextLayout.d

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00001 /*******************************************************************************
00002 
00003         @file TextLayout.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, March 2004      
00034         @author         Kris
00035                         Anders F Bjorklund (Darwin patches)
00036 
00037 
00038 *******************************************************************************/
00039 
00040 module mango.io.TextLayout;
00041 
00042 private import  mango.io.Exception;
00043 
00044 /*******************************************************************************
00045 
00046         Arranges text strings in order, using indices to specify where
00047         each particular argument should be positioned within the text. 
00048         This is handy for collating I18N components.
00049 
00050         @code
00051         // create a TextLayout instance
00052         TextLayout tl = new TextLayout (256);
00053 
00054         // write text to Stdout
00055         char[] arg1 = "one";
00056         char[] arg2 = "two";
00057         Stdout (tl.format ("%2 %1", arg1, arg2));
00058 
00059         // or access the content, post processing ...
00060         char[] text = tl.content;
00061         @endcode
00062 
00063         The index numbers range from one through nine. Note also that 
00064         this class is stateful, and is therefore not shareable across 
00065         multiple threads.
00066         
00067 *******************************************************************************/
00068 
00069 class TextLayout (Type)
00070 {       
00071         alias format opCall;
00072 
00073         private int     count;
00074         private Type[]  output;
00075                        
00076         /***********************************************************************
00077         
00078                 Set the maximum buffer length
00079 
00080         ***********************************************************************/
00081 
00082         this (int limit)
00083         {
00084                 output = new Type [limit];
00085         }
00086 
00087         /***********************************************************************
00088         
00089                 Address formatted output as a char[]
00090 
00091         ***********************************************************************/
00092 
00093         Type[] content ()
00094         {
00095                 return output [0..count];
00096         }
00097 
00098         /***********************************************************************
00099                 
00100                 layout a set of arguments
00101 
00102         ***********************************************************************/
00103 
00104         Type[] format (Type[] layout, ...)
00105         {
00106                 return _format (layout, _arguments, _argptr);
00107         }
00108 
00109         /***********************************************************************
00110                 
00111                 layout a set of arguments
00112 
00113         ***********************************************************************/
00114 
00115         private Type[] _format (Type[] layout, TypeInfo[] arguments, void *argptr)
00116         {
00117                 int     pos,
00118                         args;
00119                 bool    state;
00120                         
00121                 args = arguments.length;
00122                 foreach (Type c; layout)
00123                         {
00124                         if (state)
00125                            {
00126                            state = false;
00127                            if (c >= '1' || c <= '9')
00128                               {
00129                               uint index = c - '1';
00130                               if (index < args && arguments[index] == typeid(Type[]))
00131                                  {
00132                                  Type[] x = *cast(Type[] *) (index + cast(void[] *) argptr);
00133 
00134                                  int limit = pos + x.length;
00135                                  if (limit < output.length)
00136                                     {
00137                                     output[pos..limit] = x;
00138                                     pos = limit;
00139                                     continue;
00140                                     } 
00141                                  else
00142                                     throw new Exception ("TextLayout limit exceeded");
00143                                  }
00144                               else
00145                                  throw new Exception ("invalid layout argument");
00146                               }
00147                            }
00148                         else
00149                            if (c == '%')
00150                               {
00151                               state = true;
00152                               continue;
00153                               }
00154                 
00155                         if (pos < output.length)
00156                            {
00157                            output[pos] = c;
00158                            ++pos;
00159                            }
00160                         else     
00161                            throw new Exception ("layout buffer too small");
00162                         }
00163 
00164                 count = pos;
00165                 return content;
00166         }
00167 }
00168 
00169 alias TextLayout!(char)  LayoutChar;
00170 alias TextLayout!(wchar) LayoutWChar;
00171 alias TextLayout!(dchar) LayoutDChar;
00172 
00173 

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