gforth/blocks.fs - view

File: [gforth] / gforth / blocks.fs
Revision 1.36: download - view: text, annotated - select for diffs
Wed Dec 25 15:45:15 2002 UTC (20 years, 9 months ago) by anton
Branches: MAIN
CVS tags: HEAD

Limit blocks files to 2GB (to avoid catastrphic interaction with gforth<0.6.0)
blocks bugfixes: OPEN-BLOCKS tries to avoid deleting existing blocks files
  SAVE-BUFFERS stack underflow fixed

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: \ limit block files to 2GB; gforth <0.6.0 erases larger block files on 48: \ 32-bit systems 49: $200000 Value block-limit 50: 51: User block-fid 52: User block-offset ( -- addr ) \ gforth 53: \G User variable containing the number of the first block (default 54: \G since 0.5.0: 0). Block files created with Gforth versions before 55: \G 0.5.0 have the offset 1. If you use these files you can: @code{1 56: \G offset !}; or add 1 to every block number used; or prepend 1024 57: \G characters to the file. 58: 0 block-offset ! \ store 1 here fore 0.4.0 compatibility 59: 60: ' block-offset alias offset \ !! eliminate this? 61: 62: : block-cold ( -- ) 63: block-fid off last-block off 64: buffer-struct buffers * %alloc dup block-buffers ! ( addr ) 65: buffer-struct %size buffers * erase ; 66: 67: ' block-cold INIT8 chained 68: 69: block-cold 70: 71: Defer flush-blocks ( -- ) \ gforth 72: 73: : open-blocks ( c-addr u -- ) \ gforth 74: \g Use the file, whose name is given by @i{c-addr u}, as the blocks file. 75: try ( c-addr u ) 76: 2dup open-fpath-file throw 77: rot close-file throw 2dup file-status throw bin open-file throw 78: >r 2drop r> 79: recover ( c-addr u ior ) 80: >r 2dup file-status nip 0= r> and throw \ does it really not exist? 81: r/w bin create-file throw 82: endtry 83: block-fid @ IF 84: flush-blocks block-fid @ close-file throw 85: THEN 86: block-fid ! ; 87: 88: : use ( "file" -- ) \ gforth 89: \g Use @i{file} as the blocks file. 90: name open-blocks ; 91: 92: \ the file is opened as binary file, since it either will contain text 93: \ without newlines or binary data 94: : get-block-fid ( -- wfileid ) \ gforth 95: \G Return the file-id of the current blocks file. If no blocks 96: \G file has been opened, use @file{blocks.fb} as the default 97: \G blocks file. 98: block-fid @ 0= 99: if 100: s" blocks.fb" open-blocks 101: then 102: block-fid @ ; 103: 104: : block-position ( u -- ) \ block 105: \G Position the block file to the start of block @i{u}. 106: dup block-limit u>= -35 and throw 107: offset @ - chars/block chars um* get-block-fid reposition-file throw ; 108: 109: : update ( -- ) \ block 110: \G Mark the state of the current block buffer as assigned-dirty. 111: last-block @ ?dup IF buffer-dirty on THEN ; 112: 113: : save-buffer ( buffer -- ) \ gforth 114: >r 115: r@ buffer-dirty @ r@ buffer-block @ 0<> and 116: if 117: r@ buffer-block @ block-position 118: r@ block-buffer chars/block r@ buffer-fid @ write-file throw 119: r@ buffer-fid @ flush-file throw 120: r@ buffer-dirty off 121: endif 122: rdrop ; 123: 124: : empty-buffer ( buffer -- ) \ gforth 125: buffer-block off ; 126: 127: : save-buffers ( -- ) \ block 128: \G Transfer the contents of each @code{update}d block buffer to 129: \G mass storage, then mark all block buffers as assigned-clean. 130: block-buffers @ 131: buffers 0 ?DO dup save-buffer next-buffer LOOP drop ; 132: 133: : empty-buffers ( -- ) \ block-ext 134: \G Mark all block buffers as unassigned; if any had been marked as 135: \G assigned-dirty (by @code{update}), the changes to those blocks 136: \G will be lost. 137: block-buffers @ 138: buffers 0 ?DO dup empty-buffer next-buffer LOOP drop ; 139: 140: : flush ( -- ) \ block 141: \G Perform the functions of @code{save-buffers} then 142: \G @code{empty-buffers}. 143: save-buffers 144: empty-buffers ; 145: 146: ' flush IS flush-blocks 147: 148: : get-buffer ( u -- a-addr ) \ gforth 149: 0 buffers um/mod drop buffer-struct %size * block-buffers @ + ; 150: 151: : block ( u -- a-addr ) \ gforthman- block 152: \G If a block buffer is assigned for block @i{u}, return its 153: \G start address, @i{a-addr}. Otherwise, assign a block buffer 154: \G for block @i{u} (if the assigned block buffer has been 155: \G @code{update}d, transfer the contents to mass storage), read 156: \G the block into the block buffer and return its start address, 157: \G @i{a-addr}. 158: dup offset @ u< -35 and throw 159: dup get-buffer >r 160: dup r@ buffer-block @ <> 161: r@ buffer-fid @ block-fid @ <> or 162: if 163: r@ save-buffer 164: dup block-position 165: r@ block-buffer chars/block get-block-fid read-file throw 166: \ clear the rest of the buffer if the file is too short 167: r@ block-buffer over chars + chars/block rot chars - blank 168: r@ buffer-block ! 169: get-block-fid r@ buffer-fid ! 170: else 171: drop 172: then 173: r> dup last-block ! block-buffer ; 174: 175: : buffer ( u -- a-addr ) \ block 176: \G If a block buffer is assigned for block @i{u}, return its 177: \G start address, @i{a-addr}. Otherwise, assign a block buffer 178: \G for block @i{u} (if the assigned block buffer has been 179: \G @code{update}d, transfer the contents to mass storage) and 180: \G return its start address, @i{a-addr}. The subtle difference 181: \G between @code{buffer} and @code{block} mean that you should 182: \G only use @code{buffer} if you don't care about the previous 183: \G contents of block @i{u}. In Gforth, this simply calls 184: \G @code{block}. 185: \ reading in the block is unnecessary, but simpler 186: block ; 187: 188: User scr ( -- a-addr ) \ block-ext s-c-r 189: \G @code{User} variable -- @i{a-addr} is the address of a cell containing 190: \G the block number of the block most recently processed by 191: \G @code{list}. 192: 0 scr ! 193: 194: \ nac31Mar1999 moved "scr @" to list to make the stack comment correct 195: : updated? ( n -- f ) \ gforth 196: \G Return true if @code{updated} has been used to mark block @i{n} 197: \G as assigned-dirty. 198: buffer 199: [ 0 buffer-dirty 0 block-buffer - ] Literal + @ ; 200: 201: : list ( u -- ) \ block-ext 202: \G Display block @i{u}. In Gforth, the block is displayed as 16 203: \G numbered lines, each of 64 characters. 204: \ calling block again and again looks inefficient but is necessary 205: \ in a multitasking environment 206: dup scr ! 207: ." Screen " u. 208: scr @ updated? 0= IF ." not " THEN ." modified " cr 209: 16 0 210: ?do 211: i 2 .r space scr @ block i 64 * chars + 64 type cr 212: loop ; 213: 214: [IFDEF] current-input 215: :noname 2 <> -12 and throw >in ! blk ! ; 216: \ restore-input 217: :noname blk @ >in @ 2 ; \ save-input 218: :noname 2 ; \ source-id "*a block*" 219: :noname 1 blk +! 1 loadline +! true ; \ refill 220: :noname blk @ block chars/block ; \ source 221: 222: Create block-input A, A, A, A, A, 223: 224: : load ( i*x n -- j*x ) \ block 225: \G Save the current input source specification. Store @i{n} in 226: \G @code{BLK}, set @code{>IN} to 0 and interpret. When the parse 227: \G area is exhausted, restore the input source specification. 228: block-input 0 new-tib dup loadline ! blk ! 2 loadfilename# ! 229: ['] interpret catch pop-file throw ; 230: [ELSE] 231: : (source) ( -- c-addr u ) 232: blk @ ?dup 233: IF block chars/block 234: ELSE tib #tib @ 235: THEN ; 236: 237: ' (source) IS source ( -- c-addr u ) \ core 238: \G @i{c-addr} is the address of the input buffer and @i{u} is the 239: \G number of characters in it. 240: 241: : load ( i*x n -- j*x ) \ block 242: \G Save the current input source specification. Store @i{n} in 243: \G @code{BLK}, set @code{>IN} to 0 and interpret. When the parse 244: \G area is exhausted, restore the input source specification. 245: loadfilename# @ >r 246: 2 loadfilename# ! \ "*a block*" 247: push-file 248: dup loadline ! blk ! >in off ['] interpret catch 249: pop-file 250: r> loadfilename# ! 251: throw ; 252: [THEN] 253: 254: : thru ( i*x n1 n2 -- j*x ) \ block-ext 255: \G @code{load} the blocks @i{n1} through @i{n2} in sequence. 256: 1+ swap ?DO I load LOOP ; 257: 258: : +load ( i*x n -- j*x ) \ gforth 259: \G Used within a block to load the block specified as the 260: \G current block + @i{n}. 261: blk @ + load ; 262: 263: : +thru ( i*x n1 n2 -- j*x ) \ gforth 264: \G Used within a block to load the range of blocks specified as the 265: \G current block + @i{n1} thru the current block + @i{n2}. 266: 1+ swap ?DO I +load LOOP ; 267: 268: : --> ( -- ) \ gforthman- gforth chain 269: \G If this symbol is encountered whilst loading block @i{n}, 270: \G discard the remainder of the block and load block @i{n+1}. Used 271: \G for chaining multiple blocks together as a single loadable 272: \G unit. Not recommended, because it destroys the independence of 273: \G loading. Use @code{thru} (which is standard) or @code{+thru} 274: \G instead. 275: refill drop ; immediate 276: 277: : block-included ( a-addr u -- ) \ gforth 278: \G Use within a block that is to be processed by @code{load}. Save 279: \G the current blocks file specification, open the blocks file 280: \G specified by @i{a-addr u} and @code{load} block 1 from that 281: \G file (which may in turn chain or load other blocks). Finally, 282: \G close the blocks file and restore the original blocks file. 283: block-fid @ >r block-fid off open-blocks 284: 1 load block-fid @ close-file throw flush 285: r> block-fid ! ; 286: 287: \ thrown out because it may provide unpleasant surprises - anton 288: \ : include ( "name" -- ) 289: \ name 2dup dup 3 - /string s" .fb" compare 290: \ 0= IF block-included ELSE included THEN ; 291: 292: get-current environment-wordlist set-current 293: true constant block 294: true constant block-ext 295: set-current 296: 297: : bye ( -- ) \ tools-ext 298: \G Return control to the host operating system (if any). 299: ['] flush catch drop bye ;