File:  [gforth] / gforth / blocks.fs
Revision 1.35: download - view: text, annotated - select for diffs
Sat Sep 14 08:34:03 2002 UTC (16 years, 9 months ago) by anton
Branches: MAIN
CVS tags: HEAD
fixed bugs in compat/strcomp.fs and its usage

    1: \ A less simple implementation of the blocks wordset. 
    2: 
    3: \ Copyright (C) 1995,1996,1997,1998,2000 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
   19: \ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
   20: 
   21: 
   22: \ A more efficient implementation would use mmap on OSs that
   23: \ provide it and many buffers on OSs that do not provide mmap.
   24: 
   25: \ Now, the replacement algorithm is "direct mapped"; change to LRU
   26: \ if too slow. Using more buffers helps, too.
   27: 
   28: \ I think I avoid the assumption 1 char = 1 here, but I have not tested this
   29: 
   30: \ 1024 constant chars/block \ mandated by the standard
   31: 
   32: require struct.fs
   33: 
   34: struct
   35:     cell%		field buffer-block   \ the block number
   36:     cell%		field buffer-fid     \ the block's fid
   37:     cell%		field buffer-dirty   \ the block dirty flag
   38:     char% chars/block * field block-buffer   \ the data
   39:     cell% 0 *		field next-buffer
   40: end-struct buffer-struct
   41: 
   42: Variable block-buffers
   43: Variable last-block
   44: 
   45: $20 Value buffers
   46: 
   47: User block-fid
   48: User block-offset ( -- addr ) \ gforth
   49: \G User variable containing the number of the first block (default
   50: \G since 0.5.0: 0).  Block files created with Gforth versions before
   51: \G 0.5.0 have the offset 1.  If you use these files you can: @code{1
   52: \G offset !}; or add 1 to every block number used; or prepend 1024
   53: \G characters to the file.
   54: 0 block-offset !  \ store 1 here fore 0.4.0 compatibility
   55: 
   56: ' block-offset alias offset \ !! eliminate this?
   57: 
   58: : block-cold ( -- )
   59:     block-fid off  last-block off
   60:     buffer-struct buffers * %alloc dup block-buffers ! ( addr )
   61:     buffer-struct %size buffers * erase ;
   62: 
   63: ' block-cold INIT8 chained
   64: 
   65: block-cold
   66: 
   67: Defer flush-blocks ( -- ) \ gforth
   68: 
   69: : open-blocks ( c-addr u -- ) \ gforth
   70:     \g Use the file, whose name is given by @i{c-addr u}, as the blocks file.
   71:     2dup open-fpath-file 0<>
   72:     if
   73: 	r/w bin create-file throw
   74:     else
   75: 	rot close-file throw  2dup file-status throw bin open-file throw
   76: 	>r 2drop r>
   77:     then
   78:     block-fid @ IF  flush-blocks block-fid @ close-file throw  THEN
   79:     block-fid ! ;
   80: 
   81: : use ( "file" -- ) \ gforth
   82:     \g Use @i{file} as the blocks file.
   83:     name open-blocks ;
   84: 
   85: \ the file is opened as binary file, since it either will contain text
   86: \ without newlines or binary data
   87: : get-block-fid ( -- wfileid ) \ gforth
   88:     \G Return the file-id of the current blocks file. If no blocks
   89:     \G file has been opened, use @file{blocks.fb} as the default
   90:     \G blocks file.
   91:     block-fid @ 0=
   92:     if
   93: 	s" blocks.fb" open-blocks
   94:     then
   95:     block-fid @ ;
   96: 
   97: : block-position ( u -- ) \ block
   98:     \G Position the block file to the start of block @i{u}.
   99:     offset @ - chars/block chars um* get-block-fid reposition-file throw ;
  100: 
  101: : update ( -- ) \ block
  102:     \G Mark the state of the current block buffer as assigned-dirty.
  103:     last-block @ ?dup IF  buffer-dirty on  THEN ;
  104: 
  105: : save-buffer ( buffer -- ) \ gforth
  106:     >r
  107:     r@ buffer-dirty @ r@ buffer-block @ 0<> and
  108:     if
  109: 	r@ buffer-block @ block-position
  110: 	r@ block-buffer chars/block  r@ buffer-fid @  write-file throw
  111: 	buffer-fid @ flush-file throw
  112: 	r@ buffer-dirty off
  113:     endif
  114:     rdrop ;
  115: 
  116: : empty-buffer ( buffer -- ) \ gforth
  117:     buffer-block off ;
  118: 
  119: : save-buffers  ( -- ) \ block
  120:     \G Transfer the contents of each @code{update}d block buffer to
  121:     \G mass storage, then mark all block buffers as assigned-clean.
  122:     block-buffers @
  123:     buffers 0 ?DO dup save-buffer next-buffer LOOP drop ;
  124: 
  125: : empty-buffers ( -- ) \ block-ext
  126:     \G Mark all block buffers as unassigned; if any had been marked as
  127:     \G assigned-dirty (by @code{update}), the changes to those blocks
  128:     \G will be lost.
  129:     block-buffers @
  130:     buffers 0 ?DO dup empty-buffer next-buffer LOOP drop ;
  131: 
  132: : flush ( -- ) \ block
  133:     \G Perform the functions of @code{save-buffers} then
  134:     \G @code{empty-buffers}.
  135:     save-buffers
  136:     empty-buffers ;
  137: 
  138: ' flush IS flush-blocks
  139: 
  140: : get-buffer ( u -- a-addr ) \ gforth
  141:     0 buffers um/mod drop buffer-struct %size * block-buffers @ + ;
  142: 
  143: : block ( u -- a-addr ) \ gforthman- block
  144:     \G If a block buffer is assigned for block @i{u}, return its
  145:     \G start address, @i{a-addr}. Otherwise, assign a block buffer
  146:     \G for block @i{u} (if the assigned block buffer has been
  147:     \G @code{update}d, transfer the contents to mass storage), read
  148:     \G the block into the block buffer and return its start address,
  149:     \G @i{a-addr}.
  150:     dup offset @ u< -35 and throw
  151:     dup get-buffer >r
  152:     dup r@ buffer-block @ <>
  153:     r@ buffer-fid @ block-fid @ <> or
  154:     if
  155: 	r@ save-buffer
  156: 	dup block-position
  157: 	r@ block-buffer chars/block get-block-fid read-file throw
  158: 	\ clear the rest of the buffer if the file is too short
  159: 	r@ block-buffer over chars + chars/block rot chars - blank
  160: 	r@ buffer-block !
  161: 	get-block-fid r@ buffer-fid !
  162:     else
  163: 	drop
  164:     then
  165:     r> dup last-block ! block-buffer ;
  166: 
  167: : buffer ( u -- a-addr ) \ block
  168:     \G If a block buffer is assigned for block @i{u}, return its
  169:     \G start address, @i{a-addr}. Otherwise, assign a block buffer
  170:     \G for block @i{u} (if the assigned block buffer has been
  171:     \G @code{update}d, transfer the contents to mass storage) and
  172:     \G return its start address, @i{a-addr}.  The subtle difference
  173:     \G between @code{buffer} and @code{block} mean that you should
  174:     \G only use @code{buffer} if you don't care about the previous
  175:     \G contents of block @i{u}. In Gforth, this simply calls
  176:     \G @code{block}.
  177:     \ reading in the block is unnecessary, but simpler
  178:     block ;
  179: 
  180: User scr ( -- a-addr ) \ block-ext s-c-r
  181:     \G @code{User} variable -- @i{a-addr} is the address of a cell containing
  182:     \G the block number of the block most recently processed by
  183:     \G @code{list}.
  184: 0 scr !
  185: 
  186: \ nac31Mar1999 moved "scr @" to list to make the stack comment correct
  187: : updated?  ( n -- f ) \ gforth
  188:     \G Return true if @code{updated} has been used to mark block @i{n}
  189:     \G as assigned-dirty.
  190:     buffer
  191:     [ 0 buffer-dirty 0 block-buffer - ] Literal + @ ;
  192: 
  193: : list ( u -- ) \ block-ext
  194:     \G Display block @i{u}. In Gforth, the block is displayed as 16
  195:     \G numbered lines, each of 64 characters.
  196:     \ calling block again and again looks inefficient but is necessary
  197:     \ in a multitasking environment
  198:     dup scr !
  199:     ." Screen " u.
  200:     scr @ updated?  0= IF ." not "  THEN  ." modified     " cr
  201:     16 0
  202:     ?do
  203: 	i 2 .r space scr @ block i 64 * chars + 64 type cr
  204:     loop ;
  205: 
  206: [IFDEF] current-input
  207: :noname  2 <> -12 and throw >in ! blk ! ;
  208:                               \ restore-input
  209: :noname  blk @ >in @ 2 ;      \ save-input
  210: :noname  2 ;                  \ source-id "*a block*"
  211: :noname  1 blk +! 1 loadline +! true ;      \ refill
  212: :noname  blk @ block chars/block ;  \ source
  213: 
  214: Create block-input   A, A, A, A, A,
  215: 
  216: : load  ( i*x n -- j*x ) \ block
  217:     \G Save the current input source specification. Store @i{n} in
  218:     \G @code{BLK}, set @code{>IN} to 0 and interpret. When the parse
  219:     \G area is exhausted, restore the input source specification.
  220:     block-input 0 new-tib dup loadline ! blk !  2 loadfilename# !
  221:     ['] interpret catch pop-file throw ;
  222: [ELSE]
  223: : (source)  ( -- c-addr u )
  224:   blk @ ?dup
  225:   IF    block chars/block
  226:   ELSE  tib #tib @
  227:   THEN ;
  228: 
  229: ' (source) IS source ( -- c-addr u ) \ core
  230: \G @i{c-addr} is the address of the input buffer and @i{u} is the
  231: \G number of characters in it.
  232: 
  233: : load ( i*x n -- j*x ) \ block
  234:     \G Save the current input source specification. Store @i{n} in
  235:     \G @code{BLK}, set @code{>IN} to 0 and interpret. When the parse
  236:     \G area is exhausted, restore the input source specification.
  237:     loadfilename# @ >r
  238:     2 loadfilename# ! \ "*a block*"
  239:     push-file
  240:     dup loadline ! blk ! >in off ['] interpret catch
  241:     pop-file
  242:     r> loadfilename# !
  243:     throw ;
  244: [THEN]
  245: 
  246: : thru ( i*x n1 n2 -- j*x ) \ block-ext
  247:     \G @code{load} the blocks @i{n1} through @i{n2} in sequence.
  248:     1+ swap ?DO  I load  LOOP ;
  249: 
  250: : +load ( i*x n -- j*x ) \ gforth
  251:     \G Used within a block to load the block specified as the
  252:     \G current block + @i{n}.
  253:     blk @ + load ;
  254: 
  255: : +thru ( i*x n1 n2 -- j*x ) \ gforth
  256:     \G Used within a block to load the range of blocks specified as the
  257:     \G current block + @i{n1} thru the current block + @i{n2}.
  258:     1+ swap ?DO  I +load  LOOP ;
  259: 
  260: : --> ( -- ) \ gforthman- gforth chain
  261:     \G If this symbol is encountered whilst loading block @i{n},
  262:     \G discard the remainder of the block and load block @i{n+1}. Used
  263:     \G for chaining multiple blocks together as a single loadable
  264:     \G unit.  Not recommended, because it destroys the independence of
  265:     \G loading.  Use @code{thru} (which is standard) or @code{+thru}
  266:     \G instead.
  267:     refill drop ; immediate
  268: 
  269: : block-included ( a-addr u -- ) \ gforth
  270:     \G Use within a block that is to be processed by @code{load}. Save
  271:     \G the current blocks file specification, open the blocks file
  272:     \G specified by @i{a-addr u} and @code{load} block 1 from that
  273:     \G file (which may in turn chain or load other blocks). Finally,
  274:     \G close the blocks file and restore the original blocks file.
  275:     block-fid @ >r block-fid off open-blocks
  276:     1 load block-fid @ close-file throw flush
  277:     r> block-fid ! ;
  278: 
  279: \ thrown out because it may provide unpleasant surprises - anton
  280: \ : include ( "name" -- )
  281: \     name 2dup dup 3 - /string s" .fb" compare
  282: \     0= IF  block-included  ELSE  included  THEN ;
  283: 
  284: get-current environment-wordlist set-current
  285: true constant block
  286: true constant block-ext
  287: set-current
  288: 
  289: : bye ( -- ) \ tools-ext
  290:   \G Return control to the host operating system (if any).
  291:   ['] flush catch drop bye ;

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