File:  [gforth] / gforth / struct.fs
Revision 1.8: download - view: text, annotated - select for diffs
Tue Nov 7 18:07:02 1995 UTC (25 years, 11 months ago) by anton
Branches: MAIN
CVS tags: v0-2-1, v0-2-0, gforth-0_1beta, HEAD
added copyright headers
changes to loadfilename & co. to make savesystem transparent to
 assertions and ~~

    1: \ data structures (like C structs)
    2: 
    3: \ Copyright (C) 1995 Free Software Foundation, Inc.
    4: 
    5: \ This file is part of Gforth.
    6: 
    7: \ Gforth is free software; you can redistribute it and/or
    8: \ modify it under the terms of the GNU General Public License
    9: \ as published by the Free Software Foundation; either version 2
   10: \ of the License, or (at your option) any later version.
   11: 
   12: \ This program is distributed in the hope that it will be useful,
   13: \ but WITHOUT ANY WARRANTY; without even the implied warranty of
   14: \ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   15: \ GNU General Public License for more details.
   16: 
   17: \ You should have received a copy of the GNU General Public License
   18: \ along with this program; if not, write to the Free Software
   19: \ Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
   20: 
   21: 
   22: \ Usage example:
   23: \
   24: \ struct
   25: \     1 cells: field search-method
   26: \     1 cells: field reveal-method
   27: \ end-struct wordlist-map
   28: \
   29: \ The structure can then be extended in the following way
   30: \ wordlist-map
   31: \     1 cells: field enum-method
   32: \ end-struct ext-wordlist-map \ with the fields search-method,...,enum-method
   33: 
   34: : nalign ( addr1 n -- addr2 )
   35: \ addr2 is the aligned version of addr1 wrt the alignment size n
   36:  1- tuck +  swap invert and ;
   37: 
   38: : field ( offset1 align1 size align -- offset2 align2 )
   39: \ note: this version uses local variables
   40:      Header reveal dofield: cfa,
   41: 	>r rot r@ nalign  dup ,  ( align1 size offset )
   42: 	+ swap r> nalign ;
   43: 
   44: : end-struct ( size align -- )
   45:  2constant ;
   46: 
   47: 0 1 chars end-struct struct
   48: 
   49: \ : field  ( offset1 align1 size align -- offset2 align2 )
   50: \    create-field
   51: \    does> ( addr1 -- addr2 )
   52: \	@ + ;
   53: 
   54: \ I don't really like the "type:" syntax. Any other ideas? - anton
   55: \ Also, this seems to be somewhat general. It probably belongs to some
   56: \ other place
   57: : cells: ( n -- size align )
   58:     cells cell ;
   59: 
   60: : doubles: ( n -- size align )
   61:     2* cells cell ;
   62: 
   63: : chars: ( n -- size align )
   64:     chars 1 chars ;
   65: 
   66: : floats: ( n -- size align )
   67:     floats 1 floats ;
   68: 
   69: : dfloats: ( n -- size align )
   70:     dfloats 1 dfloats ;
   71: 
   72: : sfloats: ( n -- size align )
   73:     sfloats 1 sfloats ;
   74: 
   75: : struct-align ( size align -- )
   76:     dp @ swap nalign dp !
   77:     drop ;
   78: 
   79: : struct-allot ( size align -- addr )
   80:     over swap struct-align
   81:     here swap allot ;
   82: 
   83: : struct-allocate ( size align -- addr ior )
   84:     drop allocate ;

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