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Diffstat (limited to 'engines/glk/tads/tads2/memory_cache_swap.h')
| -rw-r--r-- | engines/glk/tads/tads2/memory_cache_swap.h | 122 |
1 files changed, 122 insertions, 0 deletions
diff --git a/engines/glk/tads/tads2/memory_cache_swap.h b/engines/glk/tads/tads2/memory_cache_swap.h new file mode 100644 index 0000000000..f1b9849aec --- /dev/null +++ b/engines/glk/tads/tads2/memory_cache_swap.h @@ -0,0 +1,122 @@ +/* ScummVM - Graphic Adventure Engine + * + * ScummVM is the legal property of its developers, whose names + * are too numerous to list here. Please refer to the COPYRIGHT + * file distributed with this source distribution. + * + * This program 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. + * + */ + +/* + * Memory cache swap manager + * + * The cache swap manager provides swap file services to the memory + * cache manager. The cache manager calls the swap manager to write + * objects to the swap file and read in previously swapped-out objects. + */ + +#ifndef GLK_TADS_TADS2_MEMORY_CACHE_SWAP +#define GLK_TADS_TADS2_MEMORY_CACHE_SWAP + +#include "glk/tads/tads2/lib.h" +#include "glk/tads/tads2/error_handling.h" +#include "glk/tads/osfrobtads.h" + +namespace Glk { +namespace TADS { +namespace TADS2 { + +/* Forward declarations */ +struct mcmcx1def; + +/** + * swap segment descriptor + */ +struct mcsdsdef { + ulong mcsdsptr; /* seek pointer in swap file */ + ushort mcsdssiz; /* size of this swap segment */ + ushort mcsdsosz; /* size of object written to segment */ + uint mcsdsobj; /* client object ID */ + ushort mcsdsflg; /* flags */ +#define MCSDSFINUSE 0x01 /* segment is in use */ +}; + +/** + * mcsseg - swap segment handle. All swap-file segments are addressed + * through this handle type. + */ +typedef ushort mcsseg; + +/** + * Swap manager context + */ +struct mcscxdef { + osfildef *mcscxfp; /* swap file handle */ + char *mcscxfname; /* name of swap file */ + errcxdef *mcscxerr; /* error handling context */ + ulong mcscxtop; /* top of swap file allocated so far */ + ulong mcscxmax; /* maximum size of swap file we're allowed */ + mcsdsdef **mcscxtab; /* swap descriptor page table */ + mcsseg mcscxmsg; /* maximum segment allocated so far */ + mcmcx1def *mcscxmem; /* memory manager context */ +}; + +#define MCSSEGINV ((mcsseg)~0) /* invalid segment ID - error indicator */ + +/* initialize swapper - returns 0 for success, other for error */ +void mcsini(struct mcscxdef *ctx, struct mcmcx1def *gmemctx, ulong maxsiz, + osfildef *fp, char *swapfilename, struct errcxdef *errctx); + +/* close swapper (release memory areas) */ +void mcsclose(struct mcscxdef *ctx); + +/** + * Swap an object out. The caller specifies the location and size of + * the object, as well as a unique handle (arbitrary, up to the caller; + * the only requirement is that it be unique among all caller objects + * and always the same for a particular caller's object) and the + * previous swap handle if the object ever had one. If the object is + * not dirty (it hasn't been written since being swapped in), and the + * swap manager hasn't reused the swap slot, the swap manager doesn't + * need to write the memory, since it already has a copy on disk; + * instead, it can just mark the slot as back in use. If the caller + * doesn't wish to take advantage of this optimization, always pass in + * dirty == TRUE, which will force a write regardless of the object ID. + */ +mcsseg mcsout(struct mcscxdef *ctx, uint objid, uchar *objptr, + ushort objsize, mcsseg oldswapseg, int dirty); + +/* Swap an object in */ +void mcsin(struct mcscxdef *ctx, mcsseg swapseg, uchar *objptr, ushort size); + + +/* number of page pointers in page table (max number of pages) */ +#define MCSPAGETAB 256 + +/* number of swap descriptors in a page */ +#define MCSPAGECNT 256 + +/* find swap descriptor corresponding to swap segment number */ +#define mcsdsc(ctx,seg) (&(ctx)->mcscxtab[(seg)>>8][(seg)&255]) + +/* write out a swap segment */ +void mcswrt(mcscxdef *ctx, mcsdsdef *desc, uchar *buf, ushort bufl); + +} // End of namespace TADS2 +} // End of namespace TADS +} // End of namespace Glk + +#endif |