Annotation of gforth/growable.fs, revision 1.2

1.1       anton       1: \ growable buffers/array
                      2: 
                      3: \ Copyright (C) 2000 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
1.2     ! anton      19: \ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
1.1       anton      20: 
                     21: struct
                     22:     cell% field growable-address1
                     23:     cell% field growable-size
                     24: end-struct growable%
                     25: 
                     26: : init-growable ( growable -- )
                     27:     0 over growable-address1 !
                     28:     1 cells swap growable-size ! ;
                     29: 
                     30: : grow-to ( u growable -- )
                     31:     \ grow growable to at least u aus
                     32:     dup >r growable-size @ begin
                     33:        2dup u> while
                     34:        2* repeat
                     35:     nip r@ growable-address1 @ over resize throw
                     36:     \ !! assumptions: resize with current address 0 is allocate;
                     37:     \ resizing to the current size is cheap
                     38:     r@ growable-address1 !
                     39:     r> growable-size ! ;
                     40: 
                     41: : growable-addr ( offset growable -- address )
                     42:     \ address at offset within growable
                     43:     growable-address1 @ + ;
                     44: 
                     45: : fit-growable ( offset usize growable -- address )
                     46:     \ address is at offset within growable; growable becomes large
                     47:     \ enough to have an object of size usize there
                     48:     >r over + r@ grow-to
                     49:     r> growable-addr ;
                     50: 
                     51: false [if] \ test code
                     52: 
                     53: growable% %allot constant x
                     54: x init-growable
                     55: x growable-size ?
                     56: 10 x grow-to
                     57: x growable-size ?
                     58: 4 x growable-addr hex.
                     59: 12 8 x fit-growable hex.
                     60: x growable-size ?
                     61: .s
                     62: 
                     63: [then]
                     64: 

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