/* * usq.c * * By Marcel J.E. Mol duteca!marcel * marcel@duteca.tudelft.nl * * I hereby place this program into public domain ... * ... all those all those if and whats etc.... * I'm completely unresposible for any damage this program may cause you. * * Usq unsqueezes a file squeezed with the apple sq3 program. * Files extracted from a binary 2 file (using unblu for example) * with a .QQ or .Q extensing are probably squeezed files. * * Usage: The program reads from a file or stdin, and outputs to * the filename stored in the squeezed file. * So use the program as follows: * * usq file.QQ * * Remember that the newline character on apple is different from Unix. * Thus files extracted with unblu, and possibly unsqueezed with usq * may have an ^M character instead of a \n character at the end of each line. * To create a proper Unix file use the following 'tr' command: * * tr '\015' '\012' < applefile > unixfile * * This program is based on the unsqueeze program in the unix/PC * ARC utility. */ /* * Squeezed file format: * 2 bytes MAGIC * 2 bytes dummy ??? * filename ended by \0 * 2 bytes node count * node count node values, each 2 bytes * squeezed data per byte */ #include #if defined(MSDOS) # include #endif #define BUFSIZE 128 #define MAGIC 0xff76 /* Squeezed file magic */ #define DLE 0x90 /* repeat byte flag */ #define NOHIST 0 /* no relevant history */ #define INREP 1 /* sending a repeated value */ #define SPEOF 256 /* special endfile token */ #define NUMVALS 257 /* 256 data values plus SPEOF */ char * copyright = "@(#) usq.c 2.1 18/06/88 (c) M.J.E. Mol"; /* * Global variable declarations */ char *progname; char *sfn; /* squeezed file name */ struct nd { /* decoding tree */ int child[2]; /* left, right */ } node[NUMVALS]; /* use large buffer */ int state; /* repeat unpacking state */ int bpos; /* last bit position read */ int curin; /* last byte value read */ int numnodes; /* number of nodes in decode tree */ /* * Functions declarations */ void main (); int unsqueeze (); void putc_ncr (); int get_int (); int init_usq (); int getc_usq (); void main(argc, argv) int argc; char ** argv; { FILE *fp; /* File pointer for squeezed file */ register int r = 0; /* Exit value */ progname = *argv; if (argc == 1) { /* no args; unsqueeze standard input */ #if defined(MSDOS) setmode(fileno(stdin), O_BINARY); #endif unsqueeze(stdin); } else /* unsqueeze each file in arglist */ while (--argc > 0) { sfn = *++argv; #if defined(MSDOS) if ((fp = fopen(sfn, "rb")) == NULL) { #else if ((fp = fopen(sfn, "r")) == NULL) { #endif perror(sfn); continue; } r |= unsqueeze(fp); fclose(fp); } exit(r); } /* main */ int unsqueeze(sfp) FILE *sfp; { register int i; register int c; /* one char of stream */ char fname[BUFSIZE]; int magic; register FILE *dfp; magic = get_int(sfp); #if defined(DEBUG) fprintf(stderr, "Magic number: %x\n", magic); #endif if (magic != MAGIC) { /* Check magic number */ fprintf(stderr, "%s: %s not a squeezed file\n", progname, sfn); fprintf(stderr, "Wrong magic number: %x\n", magic); return(1); } (void) get_int(sfp); /* two dummy bytes ??? */ i = 0; /* get the original file name */ while ((fname[i++] = getc(sfp)) != NULL) ; #if defined(MSDOS) /* open destination file */ if ((dfp = fopen(fname, "wb")) == NULL) { #else if ((dfp = fopen(fname, "w")) == NULL) { #endif perror(fname); return(1); } state = NOHIST; /* initial repeat unpacking state */ if (init_usq(sfp)) /* init unsqueeze algorithm */ return 1; while ((c=getc_usq(sfp)) != EOF) /* and unsqueeze file */ putc_ncr(c, dfp); return 0; /* file is okay */ } /* unsqueeze */ /* putc-ncr -- decode non-repeat compression. Bytes are passed one * at a time in coded format, and are written out uncoded. * The data is stored normally, except that runs of more * than two characters are represented as: * * * * With a special case that a count of zero indicates a DLE * as data, not as a repeat marker. */ void putc_ncr(c, t) /* put NCR coded bytes */ unsigned char c; /* next byte of stream */ FILE *t; /* file to receive data */ { static int lastc; /* last character seen */ switch (state) { /* action depends on our state */ case NOHIST: /* no previous history */ if (c==DLE) /* if starting a series */ state = INREP; /* then remember it next time */ else putc(lastc=c, t); /* else nothing unusual */ return; case INREP: /* in a repeat */ if (c) /* if count is nonzero */ while (--c) /* then repeatedly ... */ putc(lastc, t); /* ... output the byte */ else putc(DLE, t); /* else output DLE as data */ state = NOHIST; /* back to no history */ return; default: fprintf(stderr, "%s: bad NCR unpacking state (%d)", progname, state); } } /* putc_ncr */ int get_int(f) /* get an integer */ FILE *f; /* file to get it from */ { return getc(f) | (getc(f) << 8); } /* get_int */ int init_usq(f) /* initialize Huffman unsqueezing */ FILE *f; /* file containing squeezed data */ { register int i; /* node index */ bpos = 99; /* force initial read */ numnodes = get_int(f); /* get number of nodes */ if (numnodes<0 || numnodes>=NUMVALS) { fprintf(stderr, "%s: %s file has an invalid decode tree", progname, sfn); return 1; } /* initialize for possible empty tree (SPEOF only) */ node[0].child[0] = -(SPEOF + 1); node[0].child[1] = -(SPEOF + 1); for (i=0; i=0); )/* work down(up?) from root */ { if (++bpos > 7) { if ((curin=getc(f)) == EOF) return(EOF); bpos = 0; /* move a level deeper in tree */ i = node[i].child[1 & curin]; } else i = node[i].child[1 & (curin >>= 1)]; } /* decode fake node index to original data value */ i = i | 0xffff0000; /* Unix hack: have 32 bits instead of 16 */ i = -(i + 1); /* decode special endfile token to normal EOF */ return ((i==SPEOF) ? EOF : i); } /* getc_usq */