1 1.1 cgd /* 2 1.2 cgd * $Hdr: compress.c,v 4.0 85/07/30 12:50:00 joe Release $ 3 1.2 cgd * $Lg: compress.c,v $ 4 1.1 cgd * Revision 4.0 85/07/30 12:50:00 joe 5 1.1 cgd * Removed ferror() calls in output routine on every output except first. 6 1.1 cgd * Prepared for release to the world. 7 1.1 cgd * 8 1.1 cgd * Revision 3.6 85/07/04 01:22:21 joe 9 1.1 cgd * Remove much wasted storage by overlaying hash table with the tables 10 1.1 cgd * used by decompress: tab_suffix[1<<BITS], stack[8000]. Updated USERMEM 11 1.1 cgd * computations. Fixed dump_tab() DEBUG routine. 12 1.1 cgd * 13 1.1 cgd * Revision 3.5 85/06/30 20:47:21 jaw 14 1.1 cgd * Change hash function to use exclusive-or. Rip out hash cache. These 15 1.1 cgd * speedups render the megamemory version defunct, for now. Make decoder 16 1.1 cgd * stack global. Parts of the RCS trunks 2.7, 2.6, and 2.1 no longer apply. 17 1.1 cgd * 18 1.1 cgd * Revision 3.4 85/06/27 12:00:00 ken 19 1.1 cgd * Get rid of all floating-point calculations by doing all compression ratio 20 1.1 cgd * calculations in fixed point. 21 1.1 cgd * 22 1.1 cgd * Revision 3.3 85/06/24 21:53:24 joe 23 1.1 cgd * Incorporate portability suggestion for M_XENIX. Got rid of text on #else 24 1.1 cgd * and #endif lines. Cleaned up #ifdefs for vax and interdata. 25 1.1 cgd * 26 1.1 cgd * Revision 3.2 85/06/06 21:53:24 jaw 27 1.1 cgd * Incorporate portability suggestions for Z8000, IBM PC/XT from mailing list. 28 1.1 cgd * Default to "quiet" output (no compression statistics). 29 1.1 cgd * 30 1.1 cgd * Revision 3.1 85/05/12 18:56:13 jaw 31 1.1 cgd * Integrate decompress() stack speedups (from early pointer mods by McKie). 32 1.1 cgd * Repair multi-file USERMEM gaffe. Unify 'force' flags to mimic semantics 33 1.1 cgd * of SVR2 'pack'. Streamline block-compress table clear logic. Increase 34 1.1 cgd * output byte count by magic number size. 35 1.1 cgd * 36 1.1 cgd * Revision 3.0 84/11/27 11:50:00 petsd!joe 37 1.1 cgd * Set HSIZE depending on BITS. Set BITS depending on USERMEM. Unrolled 38 1.1 cgd * loops in clear routines. Added "-C" flag for 2.0 compatibility. Used 39 1.1 cgd * unsigned compares on Perkin-Elmer. Fixed foreground check. 40 1.1 cgd * 41 1.1 cgd * Revision 2.7 84/11/16 19:35:39 ames!jaw 42 1.1 cgd * Cache common hash codes based on input statistics; this improves 43 1.1 cgd * performance for low-density raster images. Pass on #ifdef bundle 44 1.1 cgd * from Turkowski. 45 1.1 cgd * 46 1.1 cgd * Revision 2.6 84/11/05 19:18:21 ames!jaw 47 1.1 cgd * Vary size of hash tables to reduce time for small files. 48 1.1 cgd * Tune PDP-11 hash function. 49 1.1 cgd * 50 1.1 cgd * Revision 2.5 84/10/30 20:15:14 ames!jaw 51 1.1 cgd * Junk chaining; replace with the simpler (and, on the VAX, faster) 52 1.1 cgd * double hashing, discussed within. Make block compression standard. 53 1.1 cgd * 54 1.1 cgd * Revision 2.4 84/10/16 11:11:11 ames!jaw 55 1.1 cgd * Introduce adaptive reset for block compression, to boost the rate 56 1.1 cgd * another several percent. (See mailing list notes.) 57 1.1 cgd * 58 1.1 cgd * Revision 2.3 84/09/22 22:00:00 petsd!joe 59 1.1 cgd * Implemented "-B" block compress. Implemented REVERSE sorting of tab_next. 60 1.1 cgd * Bug fix for last bits. Changed fwrite to putchar loop everywhere. 61 1.1 cgd * 62 1.1 cgd * Revision 2.2 84/09/18 14:12:21 ames!jaw 63 1.1 cgd * Fold in news changes, small machine typedef from thomas, 64 1.1 cgd * #ifdef interdata from joe. 65 1.1 cgd * 66 1.1 cgd * Revision 2.1 84/09/10 12:34:56 ames!jaw 67 1.1 cgd * Configured fast table lookup for 32-bit machines. 68 1.1 cgd * This cuts user time in half for b <= FBITS, and is useful for news batching 69 1.1 cgd * from VAX to PDP sites. Also sped up decompress() [fwrite->putc] and 70 1.1 cgd * added signal catcher [plus beef in writeerr()] to delete effluvia. 71 1.1 cgd * 72 1.1 cgd * Revision 2.0 84/08/28 22:00:00 petsd!joe 73 1.1 cgd * Add check for foreground before prompting user. Insert maxbits into 74 1.1 cgd * compressed file. Force file being uncompressed to end with ".Z". 75 1.1 cgd * Added "-c" flag and "zcat". Prepared for release. 76 1.1 cgd * 77 1.1 cgd * Revision 1.10 84/08/24 18:28:00 turtlevax!ken 78 1.1 cgd * Will only compress regular files (no directories), added a magic number 79 1.1 cgd * header (plus an undocumented -n flag to handle old files without headers), 80 1.1 cgd * added -f flag to force overwriting of possibly existing destination file, 81 1.1 cgd * otherwise the user is prompted for a response. Will tack on a .Z to a 82 1.1 cgd * filename if it doesn't have one when decompressing. Will only replace 83 1.1 cgd * file if it was compressed. 84 1.1 cgd * 85 1.1 cgd * Revision 1.9 84/08/16 17:28:00 turtlevax!ken 86 1.1 cgd * Removed scanargs(), getopt(), added .Z extension and unlimited number of 87 1.1 cgd * filenames to compress. Flags may be clustered (-Ddvb12) or separated 88 1.1 cgd * (-D -d -v -b 12), or combination thereof. Modes and other status is 89 1.1 cgd * copied with copystat(). -O bug for 4.2 seems to have disappeared with 90 1.1 cgd * 1.8. 91 1.1 cgd * 92 1.1 cgd * Revision 1.8 84/08/09 23:15:00 joe 93 1.1 cgd * Made it compatible with vax version, installed jim's fixes/enhancements 94 1.1 cgd * 95 1.1 cgd * Revision 1.6 84/08/01 22:08:00 joe 96 1.1 cgd * Sped up algorithm significantly by sorting the compress chain. 97 1.1 cgd * 98 1.1 cgd * Revision 1.5 84/07/13 13:11:00 srd 99 1.1 cgd * Added C version of vax asm routines. Changed structure to arrays to 100 1.1 cgd * save much memory. Do unsigned compares where possible (faster on 101 1.1 cgd * Perkin-Elmer) 102 1.1 cgd * 103 1.1 cgd * Revision 1.4 84/07/05 03:11:11 thomas 104 1.1 cgd * Clean up the code a little and lint it. (Lint complains about all 105 1.1 cgd * the regs used in the asm, but I'm not going to "fix" this.) 106 1.1 cgd * 107 1.1 cgd * Revision 1.3 84/07/05 02:06:54 thomas 108 1.1 cgd * Minor fixes. 109 1.1 cgd * 110 1.1 cgd * Revision 1.2 84/07/05 00:27:27 thomas 111 1.1 cgd * Add variable bit length output. 112 1.1 cgd * 113 1.1 cgd */ 114 1.1 cgd 115 1.1 cgd static char rcs_ident[] = 116 1.2 cgd "$Hdr: compress.c,v 4.0 85/07/30 12:50:00 joe Release $"; 117
Indexes created Sat Sep 20 22:09:52 GMT 2025