gforth/blocks.fs - view

File: [gforth] / gforth / blocks.fs
Revision 1.26: download - view: text, annotated - select for diffs
Sun Aug 29 21:44:44 1999 UTC (23 years, 7 months ago) by pazsan
Branches: MAIN
CVS tags: HEAD

Made block 0 the first block and provided OFFSET for backward compatibility
(store 1 there).
Fixed bug for negative buffers.
Added a type in write-file for OS-less ports.
Some corrections to make the SHARC port compile again.
HAS_DEBUG is now a central flag which replaces perror and fprintf if not set.

1: \ A less simple implementation of the blocks wordset. 2: 3: \ Copyright (C) 1995,1996,1997,1998 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., 675 Mass Ave, Cambridge, MA 02139, 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 offset 0 offset ! \ store 1 here fore 0.4.0 compatibility 49: 50: : block-cold ( -- ) 51: block-fid off last-block off 52: buffer-struct buffers * %alloc dup block-buffers ! ( addr ) 53: buffer-struct %size buffers * erase ; 54: 55: ' block-cold INIT8 chained 56: 57: block-cold 58: 59: Defer flush-blocks ( -- ) \ gforth 60: 61: : open-blocks ( c-addr u -- ) \ gforth 62: \g Use the file, whose name is given by @i{c-addr u}, as the blocks file. 63: 2dup open-fpath-file 0<> 64: if 65: r/w bin create-file throw 66: else 67: rot close-file throw 2dup file-status throw bin open-file throw 68: >r 2drop r> 69: then 70: block-fid @ IF flush-blocks block-fid @ close-file throw THEN 71: block-fid ! ; 72: 73: : use ( "file" -- ) \ gforth 74: \g Use @i{file} as the blocks file. 75: name open-blocks ; 76: 77: \ the file is opened as binary file, since it either will contain text 78: \ without newlines or binary data 79: : get-block-fid ( -- wfileid ) \ gforth 80: \G Return the file-id of the current blocks file. If no blocks 81: \G file has been opened, use @file{blocks.fb} as the default 82: \G blocks file. 83: block-fid @ 0= 84: if 85: s" blocks.fb" open-blocks 86: then 87: block-fid @ ; 88: 89: : block-position ( u -- ) \ block 90: \G Position the block file to the start of block @i{u}. 91: offset @ - chars/block chars um* get-block-fid reposition-file throw ; 92: 93: : update ( -- ) \ block 94: \G Mark the current block buffer as dirty. 95: last-block @ ?dup IF buffer-dirty on THEN ; 96: 97: : save-buffer ( buffer -- ) \ gforth 98: >r 99: r@ buffer-dirty @ r@ buffer-block @ 0<> and 100: if 101: r@ buffer-block @ block-position 102: r@ block-buffer chars/block r@ buffer-fid @ write-file throw 103: r@ buffer-dirty off 104: endif 105: rdrop ; 106: 107: : empty-buffer ( buffer -- ) \ gforth 108: buffer-block off ; 109: 110: : save-buffers ( -- ) \ block 111: \G Transfer the contents of each @code{update}d block buffer to 112: \G mass storage, then mark all block buffers as unassigned. 113: block-buffers @ 114: buffers 0 ?DO dup save-buffer next-buffer LOOP drop ; 115: 116: : empty-buffers ( -- ) \ block-ext 117: \G Mark all block buffers as unassigned; if any had been marked as 118: \G assigned-dirty (by @code{update}), the changes to those blocks 119: \G will be lost. 120: block-buffers @ 121: buffers 0 ?DO dup empty-buffer next-buffer LOOP drop ; 122: 123: : flush ( -- ) \ block 124: \G Perform the functions of @code{save-buffers} then 125: \G @code{empty-buffers}. 126: save-buffers 127: empty-buffers ; 128: 129: ' flush IS flush-blocks 130: 131: : get-buffer ( u -- a-addr ) \ gforth 132: 0 buffers um/mod drop buffer-struct %size * block-buffers @ + ; 133: 134: : block ( u -- a-addr ) \ block- block 135: \G If a block buffer is assigned for block @i{u}, return its 136: \G start address, @i{a-addr}. Otherwise, assign a block buffer 137: \G for block @i{u} (if the assigned block buffer has been 138: \G @code{update}d, transfer the contents to mass storage), read 139: \G the block into the block buffer and return its start address, 140: \G @i{a-addr}. 141: dup offset @ u< -35 and throw 142: dup get-buffer >r 143: dup r@ buffer-block @ <> 144: r@ buffer-fid @ block-fid @ <> or 145: if 146: r@ save-buffer 147: dup block-position 148: r@ block-buffer chars/block get-block-fid read-file throw 149: \ clear the rest of the buffer if the file is too short 150: r@ block-buffer over chars + chars/block rot chars - blank 151: r@ buffer-block ! 152: get-block-fid r@ buffer-fid ! 153: else 154: drop 155: then 156: r> dup last-block ! block-buffer ; 157: 158: : buffer ( u -- a-addr ) \ block 159: \G If a block buffer is assigned for block @i{u}, return its 160: \G start address, @i{a-addr}. Otherwise, assign a block buffer 161: \G for block @i{u} (if the assigned block buffer has been 162: \G @code{update}d, transfer the contents to mass storage) and 163: \G return its start address, @i{a-addr}. The subtle difference 164: \G between @code{buffer} and @code{block} mean that you should 165: \G only use @code{buffer} if you don't care about the previous 166: \G contents of block @i{u}. In Gforth, this simply calls 167: \G @code{block}. 168: \ reading in the block is unnecessary, but simpler 169: block ; 170: 171: User scr ( -- a-addr ) \ block-ext 172: \G USER VARIABLE: @i{a-addr} is the address of a cell containing 173: \G the block number of the block most recently processed by 174: \G @code{list}. 175: 0 scr ! 176: 177: \ nac31Mar1999 moved "scr @" to list to make the stack comment correct 178: : updated? ( n -- f ) \ gforth 179: \G Return true if block @i{n} has been marked as dirty. 180: buffer 181: [ 0 buffer-dirty 0 block-buffer - ] Literal + @ ; 182: 183: : list ( u -- ) \ block-ext 184: \G Display block @i{u}. In Gforth, the block is displayed as 16 185: \G numbered lines, each of 64 characters. 186: \ calling block again and again looks inefficient but is necessary 187: \ in a multitasking environment 188: dup scr ! 189: ." Screen " u. 190: scr @ updated? 0= IF ." not " THEN ." modified " cr 191: 16 0 192: ?do 193: i 2 .r space scr @ block i 64 * chars + 64 type cr 194: loop ; 195: 196: : (source) ( -- c-addr u ) 197: blk @ ?dup 198: IF block chars/block 199: ELSE tib #tib @ 200: THEN ; 201: 202: ' (source) IS source ( -- c-addr u ) \ core 203: \G @i{c-addr} is the address of the input buffer and @i{u} is the 204: \G number of characters in it. 205: 206: : load ( i*x n -- j*x ) \ block 207: \G Save the current input source specification. Store @i{n} in 208: \G @code{BLK}, set @code{>IN} to 0 and interpret. When the parse 209: \G area is exhausted, restore the input source specification. 210: push-file 211: dup loadline ! blk ! >in off ['] interpret catch 212: pop-file throw ; 213: 214: : thru ( i*x n1 n2 -- j*x ) \ block-ext 215: \G @code{load} the blocks @i{n1} through @i{n2} in sequence. 216: 1+ swap ?DO I load LOOP ; 217: 218: : +load ( i*x n -- j*x ) \ gforth 219: \G Used within a block to load the block specified as the 220: \G current block + @i{n}. 221: blk @ + load ; 222: 223: : +thru ( i*x n1 n2 -- j*x ) \ gforth 224: \G Used within a block to load the range of blocks specified as the 225: \G current block + @i{n1} thru the current block + @i{n2}. 226: 1+ swap ?DO I +load LOOP ; 227: 228: : --> ( -- ) \ gforth- gforth chain 229: \G If this symbol is encountered whilst loading block @i{n}, 230: \G discard the remainder of the block and load block @i{n+1}. Used 231: \G for chaining multiple blocks together as a single loadable 232: \G unit. Not recommended, because it destroys the independence of 233: \G loading. Use @code{thru} (which is standard) or @code{+thru} 234: \G instead. 235: refill drop ; immediate 236: 237: : block-included ( a-addr u -- ) \ gforth 238: \G Use within a block that is to be processed by @code{load}. Save 239: \G the current blocks file specification, open the blocks file 240: \G specified by @i{a-addr u} and @code{load} block 1 from that 241: \G file (which may in turn chain or load other blocks). Finally, 242: \G close the blocks file and restore the original blocks file. 243: block-fid @ >r block-fid off open-blocks 244: 1 load block-fid @ close-file throw flush 245: r> block-fid ! ; 246: 247: \ thrown out because it may provide unpleasant surprises - anton 248: \ : include ( "name" -- ) 249: \ name 2dup dup 3 - /string s" .fb" compare 250: \ 0= IF block-included ELSE included THEN ; 251: 252: get-current environment-wordlist set-current 253: true constant block 254: true constant block-ext 255: set-current 256: 257: : bye ( -- ) \ tools-ext 258: \G Return control to the host operating system (if any). 259: ['] flush catch drop bye ;