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Diffstat (limited to 'src/snap.c')
| -rw-r--r-- | src/snap.c | 200 |
1 files changed, 200 insertions, 0 deletions
diff --git a/src/snap.c b/src/snap.c new file mode 100644 index 0000000..c67c0bf --- /dev/null +++ b/src/snap.c @@ -0,0 +1,200 @@ +/* + + espec - Sinclair Spectrum emulator + + Copyright (C) 2003 Ian Cowburn (ianc@noddybox.demon.co.uk) + + 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + + ------------------------------------------------------------------------- + + Utilities for handling snapshots + +*/ +static const char ident[]="$Id$"; + +#include "snap.h" + +static const char ident_h[]=ESPEC_SNAP_H; + + +/* ---------------------------------------- MACROS +*/ +#ifndef TRUE +#define TRUE 1 +#endif + +#ifndef FALSE +#define FALSE 0 +#endif + +#define ROMLEN 0x4000 + + +/* ---------------------------------------- PRIVATE FUNCTIONS +*/ +static Z80Word GetLSBWord(FILE *fp) +{ + if (fp) + { + int c1,c2; + + c1=getc(fp); + c2=getc(fp); + + if (c1==EOF || c2==EOF) + return 0; + + return c1+(c2<<8); + } + else + return 0; +} + + +static void PutLSBWord(FILE *fp, Z80Word w) +{ + if (fp) + { + putc(w&0xff,fp); + putc(w>>8,fp); + } +} + + +static Z80Byte GetByte(FILE *fp) +{ + int c; + + if (!fp || (c=getc(fp))==EOF) + return 0; + + return c; +} + + +static void PutByte(FILE *fp, Z80Byte b) +{ + putc(b,fp); +} + + + +/* ---------------------------------------- INTERFACES +*/ +int TAPLoad(FILE *fp, Z80Byte id, Z80Word *addr, Z80Word *len, Z80Byte *mem) +{ + Z80Word blen; + Z80Byte type,b,csum,tape_csum; + + if (!fp) + return FALSE; + + /* Get length (wrapping file if at eof) + */ + blen=GetLSBWord(fp); + + if (feof(fp)) + { + rewind(fp); + blen=GetLSBWord(fp); + } + + type=GetByte(fp); + csum=id; + + /* Have we found the requested block? + */ + if (id==type) + { + /* Knock of block type + */ + blen--; + + while(blen && *len) + { + b=GetByte(fp); + csum^=b; + + if (*addr>=ROMLEN) + mem[*addr]=b; + + (*addr)++; + (*len)--; + blen--; + } + + /* Get the checksum + */ + if (blen) + { + tape_csum=GetByte(fp); + blen--; + } + else + tape_csum=b; + + /* In case we've been request less bytes than the block size + */ + while(blen--) + fgetc(fp); + + /* Check the checksum + */ + return csum==tape_csum; + } + else + { + /* If it's the wrong type, skip it + */ + while(blen--) + fgetc(fp); + + return FALSE; + } +} + + +int TAPSave(FILE *fp, Z80Byte id, Z80Word *addr, Z80Word *len, Z80Byte *mem) +{ + Z80Byte csum; + + if (!fp) + return FALSE; + + /* Write out the length and ID byte + */ + PutLSBWord(fp,(*len)+2); + PutByte(fp,id); + + /* Write out data and calc checksum + */ + csum=id; + + while(*len) + { + PutByte(fp,mem[*addr]); + csum^=mem[*addr]; + (*addr)++; + (*len)--; + } + + PutByte(fp,csum); + + return TRUE; +} + + +/* END OF FILE */ |