--- gforth/blocks.fs 1994/08/10 17:22:35 1.1 +++ gforth/blocks.fs 2007/07/06 12:54:56 1.51 @@ -1,89 +1,301 @@ -\ A simple immplementation of the blocks wordset. +\ A less simple implementation of the blocks wordset. -\ This implementation uses only a single buffer and will therefore be a -\ little slow. An efficient implementation would use mmap on OSs that -\ provide it and many buffers on OSs that do not provide mmap. +\ Copyright (C) 1995,1996,1997,1998,2000,2003,2006 Free Software Foundation, Inc. -\ I think I avoid the assumption 1 char = 1 here, but I have not tested this +\ This file is part of Gforth. + +\ Gforth is free software; you can redistribute it and/or +\ modify it under the terms of the GNU General Public License +\ as published by the Free Software Foundation; either version 2 +\ of the License, or (at your option) any later version. + +\ This program is distributed in the hope that it will be useful, +\ but WITHOUT ANY WARRANTY; without even the implied warranty of +\ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +\ GNU General Public License for more details. + +\ You should have received a copy of the GNU General Public License +\ along with this program; if not, write to the Free Software +\ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA. -1024 constant chars/block \ mandated by the standard -create block-buffer chars/block chars allot +\ A more efficient implementation would use mmap on OSs that +\ provide it and many buffers on OSs that do not provide mmap. + +\ Now, the replacement algorithm is "direct mapped"; change to LRU +\ if too slow. Using more buffers helps, too. -variable buffer-block 0 buffer-block ! \ the block currently in the buffer -variable block-fid 0 block-fid ! \ the file id of the current block file -variable buffer-dirty buffer-dirty off +\ I think I avoid the assumption 1 char = 1 here, but I have not tested this +\ 1024 constant chars/block \ mandated by the standard -: get-block-fid ( -- fid ) +require struct.fs + +struct + cell% field buffer-block \ the block number + cell% field buffer-fid \ the block's fid + cell% field buffer-dirty \ the block dirty flag + char% chars/block * field block-buffer \ the data + cell% 0 * field next-buffer +end-struct buffer-struct + +Variable block-buffers +Variable last-block + +$20 Value buffers + +\ limit block files to 2GB; gforth <0.6.0 erases larger block files on +\ 32-bit systems +$200000 Value block-limit + +User block-fid +User block-offset ( -- addr ) \ gforth +\G User variable containing the number of the first block (default +\G since 0.5.0: 0). Block files created with Gforth versions before +\G 0.5.0 have the offset 1. If you use these files you can: @code{1 +\G offset !}; or add 1 to every block number used; or prepend 1024 +\G characters to the file. +0 block-offset ! \ store 1 here fore 0.4.0 compatibility + +' block-offset alias offset \ !! eliminate this? + +: block-cold ( -- ) + block-fid off last-block off + buffer-struct buffers * %alloc dup block-buffers ! ( addr ) + buffer-struct %size buffers * erase ; + +:noname ( -- ) + defers 'cold + block-cold +; is 'cold + +block-cold + +Defer flush-blocks ( -- ) \ gforth + +: open-blocks ( c-addr u -- ) \ gforth +\g Use the file, whose name is given by @i{c-addr u}, as the blocks file. + try ( c-addr u ) + 2dup open-fpath-file throw + rot close-file throw 2dup file-status throw bin open-file throw + >r 2drop r> + endtry-iferror ( c-addr u ior ) + >r 2dup file-status nip 0= r> and throw \ does it really not exist? + r/w bin create-file throw + then + block-fid @ IF + flush-blocks block-fid @ close-file throw + THEN + block-fid ! ; + +: use ( "file" -- ) \ gforth + \g Use @i{file} as the blocks file. + name open-blocks ; + +\ the file is opened as binary file, since it either will contain text +\ without newlines or binary data +: get-block-fid ( -- wfileid ) \ gforth + \G Return the file-id of the current blocks file. If no blocks + \G file has been opened, use @file{blocks.fb} as the default + \G blocks file. block-fid @ 0= if - s" blocks.fb" r/w open-file 0<> - if - s" blocks.fb" r/w create-file .s throw - then - block-fid ! + s" blocks.fb" open-blocks then block-fid @ ; -: block-position ( u -- ) - \ positions the block file to the start of block u - 1- chars/block chars um* get-block-fid reposition-file .s throw ; - -: update ( -- ) - buffer-dirty on ; - -: save-buffers ( -- ) - buffer-dirty @ +: block-position ( u -- ) \ block +\G Position the block file to the start of block @i{u}. + dup block-limit u>= -35 and throw + offset @ - chars/block chars um* get-block-fid reposition-file throw ; + +: update ( -- ) \ block + \G Mark the state of the current block buffer as assigned-dirty. + last-block @ ?dup IF buffer-dirty on THEN ; + +: save-buffer ( buffer -- ) \ gforth + >r + r@ buffer-dirty @ if - buffer-block @ block-position - block-buffer chars/block get-block-fid write-file throw - buffer-dirty off - endif ; - -: empty-buffers ( -- ) - 0 buffer-block ! ; - -: flush ( -- ) + r@ buffer-block @ block-position + r@ block-buffer chars/block r@ buffer-fid @ write-file throw + r@ buffer-fid @ flush-file throw + r@ buffer-dirty off + endif + rdrop ; + +: empty-buffer ( buffer -- ) \ gforth + buffer-block off ; + +: save-buffers ( -- ) \ block + \G Transfer the contents of each @code{update}d block buffer to + \G mass storage, then mark all block buffers as assigned-clean. + block-buffers @ + buffers 0 ?DO dup save-buffer next-buffer LOOP drop ; + +: empty-buffers ( -- ) \ block-ext + \G Mark all block buffers as unassigned; if any had been marked as + \G assigned-dirty (by @code{update}), the changes to those blocks + \G will be lost. + block-buffers @ + buffers 0 ?DO dup empty-buffer next-buffer LOOP drop ; + +: flush ( -- ) \ block + \G Perform the functions of @code{save-buffers} then + \G @code{empty-buffers}. save-buffers empty-buffers ; -: block ( u -- a-addr ) - dup 0= -35 and throw - dup buffer-block @ <> +' flush IS flush-blocks + +: get-buffer ( u -- a-addr ) \ gforth + 0 buffers um/mod drop buffer-struct %size * block-buffers @ + ; + +: block ( u -- a-addr ) \ block + \G If a block buffer is assigned for block @i{u}, return its + \G start address, @i{a-addr}. Otherwise, assign a block buffer + \G for block @i{u} (if the assigned block buffer has been + \G @code{update}d, transfer the contents to mass storage), read + \G the block into the block buffer and return its start address, + \G @i{a-addr}. + dup offset @ u< -35 and throw + dup get-buffer >r + dup r@ buffer-block @ <> + r@ buffer-fid @ block-fid @ <> or if - save-buffers + r@ save-buffer dup block-position - block-buffer chars/block get-block-fid read-file .s throw + r@ block-buffer chars/block get-block-fid read-file throw \ clear the rest of the buffer if the file is too short - block-buffer over chars + chars/block rot - blank - buffer-block ! + r@ block-buffer over chars + chars/block rot chars - blank + r@ buffer-block ! + get-block-fid r@ buffer-fid ! else drop then - block-buffer ; + r> dup last-block ! block-buffer ; -: buffer ( u -- a-addr ) +: buffer ( u -- a-addr ) \ block + \G If a block buffer is assigned for block @i{u}, return its + \G start address, @i{a-addr}. Otherwise, assign a block buffer + \G for block @i{u} (if the assigned block buffer has been + \G @code{update}d, transfer the contents to mass storage) and + \G return its start address, @i{a-addr}. The subtle difference + \G between @code{buffer} and @code{block} mean that you should + \G only use @code{buffer} if you don't care about the previous + \G contents of block @i{u}. In Gforth, this simply calls + \G @code{block}. \ reading in the block is unnecessary, but simpler block ; -variable scr 0 scr ! \ !! this should be a user var - -: list ( u -- ) +User scr ( -- a-addr ) \ block-ext s-c-r + \G @code{User} variable -- @i{a-addr} is the address of a cell containing + \G the block number of the block most recently processed by + \G @code{list}. +0 scr ! + +\ nac31Mar1999 moved "scr @" to list to make the stack comment correct +: updated? ( n -- f ) \ gforth + \G Return true if @code{updated} has been used to mark block @i{n} + \G as assigned-dirty. + buffer + [ 0 buffer-dirty 0 block-buffer - ] Literal + @ ; + +: list ( u -- ) \ block-ext + \G Display block @i{u}. In Gforth, the block is displayed as 16 + \G numbered lines, each of 64 characters. \ calling block again and again looks inefficient but is necessary \ in a multitasking environment dup scr ! - ." Screen " u. cr + ." Screen " u. + scr @ updated? 0= IF ." not " THEN ." modified " cr 16 0 ?do - scr @ block i 64 * chars + 64 type cr + i 2 .r space scr @ block i 64 * chars + 64 type cr loop ; - -\ not yet implemented (with block semantics): - -\ evaluate -\ load -\ refill -\ thru -\ \ +[IFDEF] current-input +:noname 2 <> -12 and throw >in ! blk ! ; + \ restore-input +:noname blk @ >in @ 2 ; \ save-input +:noname 2 ; \ source-id "*a block*" +:noname 1 blk +! 1 loadline +! >in off true ; \ refill +:noname blk @ block chars/block ; \ source + +Create block-input A, A, A, A, A, + +: load ( i*x n -- j*x ) \ block + \G Save the current input source specification. Store @i{n} in + \G @code{BLK}, set @code{>IN} to 0 and interpret. When the parse + \G area is exhausted, restore the input source specification. + block-input 0 new-tib dup loadline ! blk ! s" * a block*" loadfilename 2! + ['] interpret catch pop-file throw ; +[ELSE] +: (source) ( -- c-addr u ) + blk @ ?dup + IF block chars/block + ELSE tib #tib @ + THEN ; + +' (source) IS source ( -- c-addr u ) \ core +\G @i{c-addr} is the address of the input buffer and @i{u} is the +\G number of characters in it. + +: load ( i*x n -- j*x ) \ block + \G Save the current input source specification. Store @i{n} in + \G @code{BLK}, set @code{>IN} to 0 and interpret. When the parse + \G area is exhausted, restore the input source specification. + s" * a block*" loadfilename>r + push-file + dup loadline ! blk ! >in off ['] interpret catch + pop-file + r>loadfilename + throw ; +[THEN] + +: thru ( i*x n1 n2 -- j*x ) \ block-ext + \G @code{load} the blocks @i{n1} through @i{n2} in sequence. + 1+ swap ?DO I load LOOP ; + +: +load ( i*x n -- j*x ) \ gforth + \G Used within a block to load the block specified as the + \G current block + @i{n}. + blk @ + load ; + +: +thru ( i*x n1 n2 -- j*x ) \ gforth + \G Used within a block to load the range of blocks specified as the + \G current block + @i{n1} thru the current block + @i{n2}. + 1+ swap ?DO I +load LOOP ; + +: --> ( -- ) \ gforthman- gforth chain + \G If this symbol is encountered whilst loading block @i{n}, + \G discard the remainder of the block and load block @i{n+1}. Used + \G for chaining multiple blocks together as a single loadable + \G unit. Not recommended, because it destroys the independence of + \G loading. Use @code{thru} (which is standard) or @code{+thru} + \G instead. + refill drop ; immediate + +: block-included ( a-addr u -- ) \ gforth + \G Use within a block that is to be processed by @code{load}. Save + \G the current blocks file specification, open the blocks file + \G specified by @i{a-addr u} and @code{load} block 1 from that + \G file (which may in turn chain or load other blocks). Finally, + \G close the blocks file and restore the original blocks file. + block-fid @ >r block-fid off open-blocks + 1 load block-fid @ close-file throw flush + r> block-fid ! ; + +\ thrown out because it may provide unpleasant surprises - anton +\ : include ( "name" -- ) +\ name 2dup dup 3 - /string s" .fb" compare +\ 0= IF block-included ELSE included THEN ; + +get-current environment-wordlist set-current +true constant block \ environment- environment +true constant block-ext +set-current + +: bye ( -- ) \ tools-ext + \G Return control to the host operating system (if any). + ['] flush catch drop bye ;