Path: utzoo!attcan!uunet!blkcat!p0.f40.n109.z1.fidonet.org!Kai-Uwe.Rommel
From: Kai-Uwe.Rommel@p0.f40.n109.z1.fidonet.org (Kai-Uwe Rommel)
Newsgroups: comp.os.os2
Subject: (Part 5) compress (fast!) for OS/2
Message-ID: <723.25FAE6FF@blkcat.fidonet.org>
Date: 12 Mar 90 04:39:48 GMT
Sender: ufgate@blkcat.fidonet.org (newsout1.26)
Organization: FidoNet node 1:109/40.0 - Crewe 400 Nat'l Hub, Joe Keenan
Lines: 174


	*** Split Message, part #5, MsgSplit Version 2 (11-Mar-90) ***

X                       if ((size = fread(bitbuf, 1, n_bits, stdin)) <= 0)
X                               break;
X                       /* Round size down to integral number of codes */
X                       size = (size << 3) - (n_bits - 1);
X                       bitoff = 0;
X               }
X               /*
X                * Read the next code into "code". On the 8088,
X                * a slight speedup is possible because it has the right byte
X                * order, and no alignment restrictions.
X                */
X#ifdef i8088
X               code = ((code_t)(*(long *)&bitbuf[(bitoff >> 3)] >>
X                        (bitoff&7))) & codemask;
X#else
X               bp = &bitbuf[(bitoff >> 3)];
X               code = (code_t)(((bp[0] | (code_t)bp[1] << 8) |
X                    (ulong)bp[2] << 16) >> (bitoff & 7)) & codemask;
X#endif
X               bitoff += n_bits;
X
X               if ((code == CLEAR) && block_compress) {
X                       n_bits = INIT_BITS;
X                       maxcode = MAXCODE(INIT_BITS) - 1;
X                       codemask = MAXCODE(INIT_BITS);
X                       freecode = (FIRST - 1) - 1;
X                       size = 0;
X                       continue;
X               }
X               incode = code;
X
X               /*
X                * Special case for KwKwK string.
X                */
X               if (code > freecode) {
X                       if (code != freecode + 1)
X                               oops();
X                       *stackp++ = (uchar)finchar;
X                       code = oldcode;
X               }
X
X               /*
X                * Generate output characters in reverse order
X                */
X               while (code >= 256) {
X                       *stackp++ = de_suffixof(code);
X                       code = de_prefixof(code);
X               }
X
X               /*
X                * And write them out in the forward order.
X                */
X               putchar(finchar = code);
X               for (code = (stackp - de_stack) + 1; --code != 0; )
X                       putchar(*--stackp);
X
X               /*
X                * Generate the new entry.
X                */
X               if (freecode < maxmaxcode) {
X                       if (++freecode > maxcode) {
X                               if (++n_bits == maxbits)
X                                       maxcode = maxmaxcode;
X                               else
X                                       maxcode = MAXCODE(n_bits) - 1;
X                               size = 0;
X                               codemask = MAXCODE(n_bits);
X                       }
X                       de_prefixof(freecode) = oldcode;
X                       de_suffixof(freecode) = (uchar)finchar;
X               }
X               /*
X                * Remember previous code.
X                */
X               oldcode = incode;
X       }
X       fflush(stdout);
X       if (ferror(stdout))
X               writeerr();
X}
X
X/*
X * Check a compressed file to make sure it has the proper magic number
X * at the beginning. Also read the third byte to determine "maxbits",
X * and "block_compress".
X */
Xint check_magic()
X{
X       if (! magic)
X               return (1);
X       if ((getchar() != MAGIC0) || (getchar() != MAGIC1)) {
X               fprintf(stderr, "%s: not in compressed format\n", ifname);
X               return (0);
X       }
X       maxbits = getchar();    /* set -b from file */
X       block_compress = maxbits & BLOCK_MASK;
X       maxbits &= BIT_MASK;
X       if (maxbits > BITS) {
X               fprintf(stderr,
X                  "%s: compressed with %d bits, can only handle %d bits\n",
X                   ifname, maxbits, BITS);
X               return (0);
X       }
X       return (1);
X}
X
Xvoid writeerr()
X{
X       perror(ofname);
X       fclose(stdout);
X       unlink(ofname);
X       exit(1);
X}
X
X/*
X * Copy the permissions and file times from the input file to the
X * output.
X */
Xvoid copystat()
X{
X       struct stat statbuf;
X       int mode;
X       void (* ss)();
X#ifndef __TURBOC__
X       time_t timep[2];
X#else
X       struct ftime filetime;
X       int fd;
X#endif
X
X       fclose(stdout);
X       if (stat(ifname, &statbuf)) {           /* Get stat on input file */
X               perror(ifname);
X               return;
X       }
X       if ((statbuf.st_mode & S_IFMT) != S_IFREG) {
X               if (! verbose)
X                       fprintf(stderr, "%s: ", ifname);
X               fprintf(stderr, " -- not a regular file: unchanged");
X               exit_stat = 1;
X       }
X       else if (statbuf.st_nlink > 1) {
X               if (! verbose)
X                       fprintf(stderr, "%s: ", ifname);
X               fprintf(stderr, " -- has %d other links: unchanged",
X                       statbuf.st_nlink - 1);
X               exit_stat = 1;
X       }
X       else if (exit_stat == 2 && !force) { /* No compression: remove file.Z */
X               if (verbose)
X                       fprintf(stderr, " -- file unchanged");
X       }
X       else {                  /* ***** Successful Compression ***** */
X               exit_stat = 0;
X               mode = statbuf.st_mode & 07777;
X#ifndef __ZTC__
X               if (chmod(ofname, mode))                /* Copy modes */
X                       perror(ofname);
X#endif
X#ifndef MSDOS

	*** Original message split, continued in next message ***
e



--  

	Kai-Uwe Rommel at The Black Cat's Shack (Fidonet 1:109/401)
	Internet:  Kai-Uwe.Rommel@p0.f40.n109.z1.fidonet.org    
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