Annotation of gforth/growable.fs, revision 1.4

1.1       anton       1: \ growable buffers/array
                      2: 
1.4     ! anton       3: \ Copyright (C) 2000,2007 Free Software Foundation, Inc.
1.1       anton       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
1.3       anton       9: \ as published by the Free Software Foundation, either version 3
1.1       anton      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
1.3       anton      18: \ along with this program. If not, see http://www.gnu.org/licenses/.
1.1       anton      19: 
                     20: struct
                     21:     cell% field growable-address1
                     22:     cell% field growable-size
                     23: end-struct growable%
                     24: 
                     25: : init-growable ( growable -- )
                     26:     0 over growable-address1 !
                     27:     1 cells swap growable-size ! ;
                     28: 
                     29: : grow-to ( u growable -- )
                     30:     \ grow growable to at least u aus
                     31:     dup >r growable-size @ begin
                     32:        2dup u> while
                     33:        2* repeat
                     34:     nip r@ growable-address1 @ over resize throw
                     35:     \ !! assumptions: resize with current address 0 is allocate;
                     36:     \ resizing to the current size is cheap
                     37:     r@ growable-address1 !
                     38:     r> growable-size ! ;
                     39: 
                     40: : growable-addr ( offset growable -- address )
                     41:     \ address at offset within growable
                     42:     growable-address1 @ + ;
                     43: 
                     44: : fit-growable ( offset usize growable -- address )
                     45:     \ address is at offset within growable; growable becomes large
                     46:     \ enough to have an object of size usize there
                     47:     >r over + r@ grow-to
                     48:     r> growable-addr ;
                     49: 
                     50: false [if] \ test code
                     51: 
                     52: growable% %allot constant x
                     53: x init-growable
                     54: x growable-size ?
                     55: 10 x grow-to
                     56: x growable-size ?
                     57: 4 x growable-addr hex.
                     58: 12 8 x fit-growable hex.
                     59: x growable-size ?
                     60: .s
                     61: 
                     62: [then]
                     63: 

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