1 /* Because this code is derived from the 4.3BSD compress source:
4 * Copyright (c) 1985, 1986 The Regents of the University of California.
7 * This code is derived from software contributed to Berkeley by
8 * James A. Woods, derived from original work by Spencer Thomas
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
19 * 3. All advertising materials mentioning features or use of this software
20 * must display the following acknowledgement:
21 * This product includes software developed by the University of
22 * California, Berkeley and its contributors.
23 * 4. Neither the name of the University nor the names of its contributors
24 * may be used to endorse or promote products derived from this software
25 * without specific prior written permission.
27 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
28 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
29 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
30 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
31 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
32 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
33 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
34 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
35 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
36 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
41 * This version is for use with STREAMS under SunOS 4.x.
43 * $Id: bsd-comp.c,v 1.7 1994/11/30 05:29:36 paulus Exp $
46 #include <sys/param.h>
47 #include <sys/types.h>
48 #include <sys/stream.h>
49 #include <sys/kmem_alloc.h>
50 #include <sys/socket.h>
52 #include <net/ppp_defs.h>
53 #include <net/ppp_str.h>
55 #define PACKETPTR mblk_t *
56 #include <net/ppp-comp.h>
59 * PPP "BSD compress" compression
60 * The differences between this compression and the classic BSD LZW
61 * source are obvious from the requirement that the classic code worked
62 * with files while this handles arbitrarily long streams that
63 * are broken into packets. They are:
65 * When the code size expands, a block of junk is not emitted by
66 * the compressor and not expected by the decompressor.
68 * New codes are not necessarily assigned every time an old
69 * code is output by the compressor. This is because a packet
70 * end forces a code to be emitted, but does not imply that a
71 * new sequence has been seen.
73 * The compression ratio is checked at the first end of a packet
74 * after the appropriate gap. Besides simplifying and speeding
75 * things up, this makes it more likely that the transmitter
76 * and receiver will agree when the dictionary is cleared when
77 * compression is not going well.
81 * Macros to extract protocol version and number of bits
82 * from the third byte of the BSD Compress CCP configuration option.
84 #define BSD_VERSION(x) ((x) >> 5)
85 #define BSD_NBITS(x) ((x) & 0x1F)
87 #define BSD_CURRENT_VERSION 1
90 * A dictionary for doing BSD compress.
93 int totlen; /* length of this structure */
94 u_int hsize; /* size of the hash table */
95 u_char hshift; /* used in hash function */
96 u_char n_bits; /* current bits/code */
100 u_short seqno; /* sequence number of next packet */
101 u_int hdrlen; /* header length to preallocate */
103 u_int maxmaxcode; /* largest valid code */
104 u_int max_ent; /* largest code in use */
105 u_int in_count; /* uncompressed bytes, aged */
106 u_int bytes_out; /* compressed bytes, aged */
107 u_int ratio; /* recent compression ratio */
108 u_int checkpoint; /* when to next check the ratio */
109 u_int clear_count; /* times dictionary cleared */
110 u_int incomp_count; /* incompressible packets */
111 u_int incomp_bytes; /* incompressible bytes */
112 u_int uncomp_count; /* uncompressed packets */
113 u_int uncomp_bytes; /* uncompressed bytes */
114 u_int comp_count; /* compressed packets */
115 u_int comp_bytes; /* compressed bytes */
116 u_short *lens; /* array of lengths of codes */
118 union { /* hash value */
121 #ifdef BSD_LITTLE_ENDIAN
122 u_short prefix; /* preceding code */
123 u_char suffix; /* last character of new code */
127 u_char suffix; /* last character of new code */
128 u_short prefix; /* preceding code */
132 u_short codem1; /* output of hash table -1 */
133 u_short cptr; /* map code to hash table entry */
137 #define BSD_OVHD 2 /* BSD compress overhead/packet */
138 #define MIN_BSD_BITS 9
139 #define BSD_INIT_BITS MIN_BSD_BITS
140 #define MAX_BSD_BITS 15
142 static void *bsd_comp_alloc __P((u_char *options, int opt_len));
143 static void *bsd_decomp_alloc __P((u_char *options, int opt_len));
144 static void bsd_free __P((void *state));
145 static int bsd_comp_init __P((void *state, u_char *options, int opt_len,
146 int unit, int debug));
147 static int bsd_decomp_init __P((void *state, u_char *options, int opt_len,
148 int unit, int hdrlen, int mru, int debug));
149 static int bsd_compress __P((void *state, mblk_t **mret,
150 mblk_t *mp, int slen, int maxolen));
151 static void bsd_incomp __P((void *state, mblk_t *dmsg));
152 static int bsd_decompress __P((void *state, mblk_t *cmp, mblk_t **dmpp));
153 static void bsd_reset __P((void *state));
154 static void bsd_comp_stats __P((void *state, struct compstat *stats));
157 * Procedures exported to ppp_comp.c.
159 struct compressor ppp_bsd_compress = {
160 0x21, /* compress_proto */
161 bsd_comp_alloc, /* comp_alloc */
162 bsd_free, /* comp_free */
163 bsd_comp_init, /* comp_init */
164 bsd_reset, /* comp_reset */
165 bsd_compress, /* compress */
166 bsd_comp_stats, /* comp_stat */
167 bsd_decomp_alloc, /* decomp_alloc */
168 bsd_free, /* decomp_free */
169 bsd_decomp_init, /* decomp_init */
170 bsd_reset, /* decomp_reset */
171 bsd_decompress, /* decompress */
172 bsd_incomp, /* incomp */
173 bsd_comp_stats, /* decomp_stat */
177 * the next two codes should not be changed lightly, as they must not
178 * lie within the contiguous general code space.
180 #define CLEAR 256 /* table clear output code */
181 #define FIRST 257 /* first free entry */
184 #define MAXCODE(b) ((1 << (b)) - 1)
185 #define BADCODEM1 MAXCODE(MAX_BSD_BITS);
187 #define BSD_HASH(prefix,suffix,hshift) ((((u_int32_t)(suffix)) << (hshift)) \
188 ^ (u_int32_t)(prefix))
189 #define BSD_KEY(prefix,suffix) ((((u_int32_t)(suffix)) << 16) \
190 + (u_int32_t)(prefix))
192 #define CHECK_GAP 10000 /* Ratio check interval */
194 #define RATIO_SCALE_LOG 8
195 #define RATIO_SCALE (1<<RATIO_SCALE_LOG)
196 #define RATIO_MAX (0x7fffffff>>RATIO_SCALE_LOG)
198 #define DECOMP_CHUNK 256
201 * clear the dictionary
208 db->max_ent = FIRST-1;
209 db->n_bits = BSD_INIT_BITS;
213 db->incomp_count = 0;
214 db->checkpoint = CHECK_GAP;
218 * If the dictionary is full, then see if it is time to reset it.
220 * Compute the compression ratio using fixed-point arithmetic
221 * with 8 fractional bits.
223 * Since we have an infinite stream instead of a single file,
224 * watch only the local compression ratio.
226 * Since both peers must reset the dictionary at the same time even in
227 * the absence of CLEAR codes (while packets are incompressible), they
228 * must compute the same ratio.
230 static int /* 1=output CLEAR */
236 if (db->in_count >= db->checkpoint) {
237 /* age the ratio by limiting the size of the counts */
238 if (db->in_count >= RATIO_MAX
239 || db->bytes_out >= RATIO_MAX) {
240 db->in_count -= db->in_count/4;
241 db->bytes_out -= db->bytes_out/4;
244 db->checkpoint = db->in_count + CHECK_GAP;
246 if (db->max_ent >= db->maxmaxcode) {
247 /* Reset the dictionary only if the ratio is worse,
248 * or if it looks as if it has been poisoned
249 * by incompressible data.
251 * This does not overflow, because
252 * db->in_count <= RATIO_MAX.
254 new_ratio = db->in_count << RATIO_SCALE_LOG;
255 if (db->bytes_out != 0)
256 new_ratio /= db->bytes_out;
258 if (new_ratio < db->ratio || new_ratio < 1 * RATIO_SCALE) {
262 db->ratio = new_ratio;
272 bsd_comp_stats(state, stats)
274 struct compstat *stats;
276 struct bsd_db *db = (struct bsd_db *) state;
279 stats->unc_bytes = db->uncomp_bytes;
280 stats->unc_packets = db->uncomp_count;
281 stats->comp_bytes = db->comp_bytes;
282 stats->comp_packets = db->comp_count;
283 stats->inc_bytes = db->incomp_bytes;
284 stats->inc_packets = db->incomp_count;
285 stats->ratio = db->in_count;
287 if (stats->ratio <= 0x7fffff)
296 * Reset state, as on a CCP ResetReq.
302 struct bsd_db *db = (struct bsd_db *) state;
310 * Allocate space for a (de) compressor.
313 bsd_alloc(options, opt_len, decomp)
318 u_int newlen, hsize, hshift, maxmaxcode;
321 if (opt_len != 3 || options[0] != 0x21 || options[1] != 3
322 || BSD_VERSION(options[2]) != BSD_CURRENT_VERSION)
324 bits = BSD_NBITS(options[2]);
326 case 9: /* needs 82152 for both directions */
327 case 10: /* needs 84144 */
328 case 11: /* needs 88240 */
329 case 12: /* needs 96432 */
333 case 13: /* needs 176784 */
337 case 14: /* needs 353744 */
341 case 15: /* needs 691440 */
345 case 16: /* needs 1366160--far too much, */
346 /* hsize = 69001; */ /* and 69001 is too big for cptr */
347 /* hshift = 8; */ /* in struct bsd_db */
353 maxmaxcode = MAXCODE(bits);
354 newlen = sizeof(*db) + (hsize-1) * (sizeof(db->dict[0]));
355 db = (struct bsd_db *) kmem_alloc(newlen, KMEM_NOSLEEP);
358 bzero(db, sizeof(*db) - sizeof(db->dict));
363 db->lens = (u_short *) kmem_alloc((maxmaxcode+1) * sizeof(db->lens[0]),
366 kmem_free(db, newlen);
374 db->maxmaxcode = maxmaxcode;
384 struct bsd_db *db = (struct bsd_db *) state;
387 kmem_free(db->lens, (db->maxmaxcode+1) * sizeof(db->lens[0]));
388 kmem_free(db, db->totlen);
392 bsd_comp_alloc(options, opt_len)
396 return bsd_alloc(options, opt_len, 0);
400 bsd_decomp_alloc(options, opt_len)
404 return bsd_alloc(options, opt_len, 1);
408 * Initialize the database.
411 bsd_init(db, options, opt_len, unit, hdrlen, mru, debug, decomp)
414 int opt_len, unit, hdrlen, mru, debug, decomp;
418 if (opt_len != 3 || options[0] != 0x21 || options[1] != 3
419 || BSD_VERSION(options[2]) != BSD_CURRENT_VERSION
420 || BSD_NBITS(options[2]) != db->maxbits
421 || decomp && db->lens == NULL)
431 db->dict[--i].codem1 = BADCODEM1;
432 db->dict[i].cptr = 0;
447 bsd_comp_init(state, options, opt_len, unit, debug)
450 int opt_len, unit, debug;
452 return bsd_init((struct bsd_db *) state, options, opt_len,
453 unit, 0, 0, debug, 0);
457 bsd_decomp_init(state, options, opt_len, unit, hdrlen, mru, debug)
460 int opt_len, unit, hdrlen, mru, debug;
462 return bsd_init((struct bsd_db *) state, options, opt_len,
463 unit, hdrlen, mru, debug, 1);
469 * One change from the BSD compress command is that when the
470 * code size expands, we do not output a bunch of padding.
472 static int /* new slen */
473 bsd_compress(state, mretp, mp, slen, maxolen)
475 mblk_t **mretp; /* return compressed mbuf chain here */
476 mblk_t *mp; /* from here */
477 int slen; /* uncompressed length */
478 int maxolen; /* max compressed length */
480 struct bsd_db *db = (struct bsd_db *) state;
481 int hshift = db->hshift;
482 u_int max_ent = db->max_ent;
483 u_int n_bits = db->n_bits;
485 u_int32_t accm = 0, fcode;
486 struct bsd_dict *dictp;
488 int hval, disp, ent, ilen;
495 #define PUTBYTE(v) { \
498 if (wptr >= cp_end) { \
503 cp_end = m->b_datap->db_lim; \
511 #define OUTPUT(ent) { \
513 accm |= ((ent) << bitno); \
515 PUTBYTE(accm >> 24); \
518 } while (bitno <= 24); \
522 * First get the protocol and check that we're
523 * interested in this packet.
527 if (rptr + PPP_HDRLEN > mp->b_wptr) {
528 if (!pullupmsg(mp, PPP_HDRLEN))
532 ent = PPP_PROTOCOL(rptr); /* get the protocol */
533 if (ent < 0x21 || ent > 0xf9)
536 /* Don't generate compressed packets which are larger than
537 the uncompressed packet. */
541 /* Allocate enough message blocks to give maxolen total space. */
543 for (olen = maxolen; olen > 0; ) {
544 m = allocb((olen < 4096? olen: 4096), BPRI_MED);
554 olen -= m->b_datap->db_lim - m->b_wptr;
558 if ((m = mret) != NULL) {
560 cp_end = m->b_datap->db_lim;
562 wptr = cp_end = NULL;
566 * Copy the PPP header over, changing the protocol,
567 * and install the 2-byte sequence number.
570 wptr[0] = PPP_ADDRESS(rptr);
571 wptr[1] = PPP_CONTROL(rptr);
572 wptr[2] = 0; /* change the protocol */
574 wptr[4] = db->seqno >> 8;
576 wptr += PPP_HDRLEN + BSD_OVHD;
581 slen = mp->b_wptr - rptr;
589 slen = np->b_wptr - rptr;
592 continue; /* handle 0-length buffers */
598 fcode = BSD_KEY(ent, c);
599 hval = BSD_HASH(ent, c, hshift);
600 dictp = &db->dict[hval];
602 /* Validate and then check the entry. */
603 if (dictp->codem1 >= max_ent)
605 if (dictp->f.fcode == fcode) {
606 ent = dictp->codem1+1;
607 continue; /* found (prefix,suffix) */
610 /* continue probing until a match or invalid entry */
611 disp = (hval == 0) ? 1 : hval;
614 if (hval >= db->hsize)
616 dictp = &db->dict[hval];
617 if (dictp->codem1 >= max_ent)
619 } while (dictp->f.fcode != fcode);
620 ent = dictp->codem1 + 1; /* finally found (prefix,suffix) */
624 OUTPUT(ent); /* output the prefix */
626 /* code -> hashtable */
627 if (max_ent < db->maxmaxcode) {
628 struct bsd_dict *dictp2;
629 /* expand code size if needed */
630 if (max_ent >= MAXCODE(n_bits))
631 db->n_bits = ++n_bits;
633 /* Invalidate old hash table entry using
634 * this code, and then take it over.
636 dictp2 = &db->dict[max_ent+1];
637 if (db->dict[dictp2->cptr].codem1 == max_ent)
638 db->dict[dictp2->cptr].codem1 = BADCODEM1;
640 dictp->codem1 = max_ent;
641 dictp->f.fcode = fcode;
643 db->max_ent = ++max_ent;
648 OUTPUT(ent); /* output the last code */
649 db->bytes_out += olen;
650 db->in_count += ilen;
652 ++db->bytes_out; /* count complete bytes */
655 OUTPUT(CLEAR); /* do not count the CLEAR */
658 * Pad dribble bits of last code with ones.
659 * Do not emit a completely useless byte of ones.
662 PUTBYTE((accm | (0xff << (bitno-8))) >> 24);
665 * Increase code size if we would have without the packet
666 * boundary and as the decompressor will.
668 if (max_ent >= MAXCODE(n_bits) && max_ent < db->maxmaxcode)
671 db->uncomp_bytes += ilen;
673 if (olen + PPP_HDRLEN + BSD_OVHD > maxolen && mret != NULL) {
674 /* throw away the compressed stuff if it is longer than uncompressed */
678 db->incomp_bytes += ilen;
679 } else if (wptr != NULL) {
686 db->comp_bytes += olen + BSD_OVHD;
690 return olen + PPP_HDRLEN + BSD_OVHD;
697 * Update the "BSD Compress" dictionary on the receiver for
698 * incompressible data by pretending to compress the incoming data.
701 bsd_incomp(state, dmsg)
705 struct bsd_db *db = (struct bsd_db *) state;
706 u_int hshift = db->hshift;
707 u_int max_ent = db->max_ent;
708 u_int n_bits = db->n_bits;
709 struct bsd_dict *dictp;
719 if (rptr + PPP_HDRLEN > dmsg->b_wptr) {
720 if (!pullupmsg(dmsg, PPP_HDRLEN))
724 ent = PPP_PROTOCOL(rptr); /* get the protocol */
725 if (ent < 0x21 || ent > 0xf9)
730 ilen = 1; /* count the protocol as 1 byte */
733 slen = dmsg->b_wptr - rptr;
739 continue; /* skip zero-length buffers */
745 fcode = BSD_KEY(ent, c);
746 hval = BSD_HASH(ent, c, hshift);
747 dictp = &db->dict[hval];
749 /* validate and then check the entry */
750 if (dictp->codem1 >= max_ent)
752 if (dictp->f.fcode == fcode) {
753 ent = dictp->codem1+1;
754 continue; /* found (prefix,suffix) */
757 /* continue probing until a match or invalid entry */
758 disp = (hval == 0) ? 1 : hval;
761 if (hval >= db->hsize)
763 dictp = &db->dict[hval];
764 if (dictp->codem1 >= max_ent)
766 } while (dictp->f.fcode != fcode);
767 ent = dictp->codem1+1;
768 continue; /* finally found (prefix,suffix) */
770 nomatch: /* output (count) the prefix */
773 /* code -> hashtable */
774 if (max_ent < db->maxmaxcode) {
775 struct bsd_dict *dictp2;
776 /* expand code size if needed */
777 if (max_ent >= MAXCODE(n_bits))
778 db->n_bits = ++n_bits;
780 /* Invalidate previous hash table entry
781 * assigned this code, and then take it over.
783 dictp2 = &db->dict[max_ent+1];
784 if (db->dict[dictp2->cptr].codem1 == max_ent)
785 db->dict[dictp2->cptr].codem1 = BADCODEM1;
787 dictp->codem1 = max_ent;
788 dictp->f.fcode = fcode;
790 db->max_ent = ++max_ent;
791 db->lens[max_ent] = db->lens[ent]+1;
794 } while (--slen != 0);
796 bitno += n_bits; /* output (count) the last code */
797 db->bytes_out += bitno/8;
798 db->in_count += ilen;
802 db->incomp_bytes += ilen;
804 db->uncomp_bytes += ilen;
806 /* Increase code size if we would have without the packet
807 * boundary and as the decompressor will.
809 if (max_ent >= MAXCODE(n_bits) && max_ent < db->maxmaxcode)
815 * Decompress "BSD Compress"
817 * Because of patent problems, we return DECOMP_ERROR for errors
818 * found by inspecting the input data and for system problems, but
819 * DECOMP_FATALERROR for any errors which could possibly be said to
820 * be being detected "after" decompression. For DECOMP_ERROR,
821 * we can issue a CCP reset-request; for DECOMP_FATALERROR, we may be
822 * infringing a patent of Motorola's if we do, so we take CCP down
825 * Given that the frame has the correct sequence number and a good FCS,
826 * errors such as invalid codes in the input most likely indicate a
827 * bug, so we return DECOMP_FATALERROR for them in order to turn off
828 * compression, even though they are detected by inspecting the input.
831 bsd_decompress(state, cmsg, dmpp)
833 mblk_t *cmsg, **dmpp;
835 struct bsd_db *db = (struct bsd_db *) state;
836 u_int max_ent = db->max_ent;
838 u_int bitno = 32; /* 1st valid bit in accm */
839 u_int n_bits = db->n_bits;
840 u_int tgtbitno = 32-n_bits; /* bitno when we have a code */
841 struct bsd_dict *dictp;
842 int explen, i, seq, len;
843 u_int incode, oldcode, finchar;
844 u_char *p, *rptr, *wptr;
846 int adrs, ctrl, ilen;
847 int dlen, space, codelen, extra;
850 * Get at least the BSD Compress header in the first buffer
853 if (rptr + PPP_HDRLEN + BSD_OVHD >= cmsg->b_wptr) {
854 if (!pullupmsg(cmsg, PPP_HDRLEN + BSD_OVHD + 1)) {
856 printf("bsd_decomp%d: failed to pullup\n", db->unit);
863 * Save the address/control from the PPP header
864 * and then get the sequence number.
866 adrs = PPP_ADDRESS(rptr);
867 ctrl = PPP_CONTROL(rptr);
869 seq = (rptr[0] << 8) + rptr[1];
871 ilen = len = cmsg->b_wptr - rptr;
874 * Check the sequence number and give up if it is not what we expect.
876 if (seq != db->seqno++) {
878 printf("bsd_decomp%d: bad sequence # %d, expected %d\n",
879 db->unit, seq, db->seqno - 1);
884 * Allocate one message block to start with.
886 if ((dmsg = allocb(DECOMP_CHUNK + db->hdrlen, BPRI_MED)) == NULL)
889 dmsg->b_wptr += db->hdrlen;
890 dmsg->b_rptr = wptr = dmsg->b_wptr;
892 /* Fill in the ppp header, but not the last byte of the protocol
893 (that comes from the decompressed data). */
897 wptr += PPP_HDRLEN - 1;
898 space = dmsg->b_datap->db_lim - wptr;
905 if (!cmsg) /* quit at end of message */
908 len = cmsg->b_wptr - rptr;
910 continue; /* handle 0-length buffers */
914 * Accumulate bytes until we have a complete code.
915 * Then get the next code, relying on the 32-bit,
916 * unsigned accm to mask the result.
919 accm |= *rptr++ << bitno;
921 if (tgtbitno < bitno)
923 incode = accm >> tgtbitno;
927 if (incode == CLEAR) {
929 * The dictionary must only be cleared at
930 * the end of a packet. But there could be an
931 * empty message block at the end.
933 if (len > 0 || cmsg->b_cont != 0) {
935 len += msgdsize(cmsg->b_cont);
939 printf("bsd_decomp%d: bad CLEAR\n", db->unit);
940 return DECOMP_FATALERROR;
948 if (incode > max_ent + 2 || incode > db->maxmaxcode
949 || incode > max_ent && oldcode == CLEAR) {
952 printf("bsd_decomp%d: bad code 0x%x oldcode=0x%x ",
953 db->unit, incode, oldcode);
954 printf("max_ent=0x%x dlen=%d seqno=%d\n",
955 max_ent, dlen, db->seqno);
957 return DECOMP_FATALERROR; /* probably a bug */
960 /* Special case for KwKwK string. */
961 if (incode > max_ent) {
969 codelen = db->lens[finchar];
970 explen += codelen + extra;
971 if (explen > db->mru + 1) {
974 printf("bsd_decomp%d: ran out of mru\n", db->unit);
975 return DECOMP_FATALERROR;
979 * Decode this code and install it in the decompressed buffer.
981 space -= codelen + extra;
983 /* Allocate another message block. */
985 dlen = codelen + extra;
986 if (dlen < DECOMP_CHUNK)
988 if ((dmsg->b_cont = allocb(dlen, BPRI_MED)) == NULL) {
994 space = dmsg->b_datap->db_lim - wptr - codelen - extra;
996 p = (wptr += codelen);
997 while (finchar > LAST) {
998 dictp = &db->dict[db->dict[finchar].cptr];
1003 printf("bsd_decomp%d: fell off end of chain ", db->unit);
1004 printf("0x%x at 0x%x by 0x%x, max_ent=0x%x\n",
1005 incode, finchar, db->dict[finchar].cptr, max_ent);
1006 return DECOMP_FATALERROR;
1008 if (dictp->codem1 != finchar-1) {
1010 printf("bsd_decomp%d: bad code chain 0x%x finchar=0x%x ",
1011 db->unit, incode, finchar);
1012 printf("oldcode=0x%x cptr=0x%x codem1=0x%x\n", oldcode,
1013 db->dict[finchar].cptr, dictp->codem1);
1014 return DECOMP_FATALERROR;
1017 *--p = dictp->f.hs.suffix;
1018 finchar = dictp->f.hs.prefix;
1024 printf("bsd_decomp%d: short by %d after code 0x%x, max_ent=0x%x\n",
1025 db->unit, codelen, incode, max_ent);
1028 if (extra) /* the KwKwK case again */
1032 * If not first code in a packet, and
1033 * if not out of code space, then allocate a new code.
1035 * Keep the hash table correct so it can be used
1036 * with uncompressed packets.
1038 if (oldcode != CLEAR && max_ent < db->maxmaxcode) {
1039 struct bsd_dict *dictp2;
1043 fcode = BSD_KEY(oldcode,finchar);
1044 hval = BSD_HASH(oldcode,finchar,db->hshift);
1045 dictp = &db->dict[hval];
1047 /* look for a free hash table entry */
1048 if (dictp->codem1 < max_ent) {
1049 disp = (hval == 0) ? 1 : hval;
1052 if (hval >= db->hsize)
1054 dictp = &db->dict[hval];
1055 } while (dictp->codem1 < max_ent);
1059 * Invalidate previous hash table entry
1060 * assigned this code, and then take it over
1062 dictp2 = &db->dict[max_ent+1];
1063 if (db->dict[dictp2->cptr].codem1 == max_ent) {
1064 db->dict[dictp2->cptr].codem1 = BADCODEM1;
1066 dictp2->cptr = hval;
1067 dictp->codem1 = max_ent;
1068 dictp->f.fcode = fcode;
1070 db->max_ent = ++max_ent;
1071 db->lens[max_ent] = db->lens[oldcode]+1;
1073 /* Expand code size if needed. */
1074 if (max_ent >= MAXCODE(n_bits) && max_ent < db->maxmaxcode) {
1075 db->n_bits = ++n_bits;
1076 tgtbitno = 32-n_bits;
1081 dmsg->b_wptr = wptr;
1084 * Keep the checkpoint right so that incompressible packets
1085 * clear the dictionary at the right times.
1087 db->bytes_out += ilen;
1088 db->in_count += explen;
1089 if (bsd_check(db) && db->debug) {
1090 printf("bsd_decomp%d: peer should have cleared dictionary\n",
1095 db->comp_bytes += ilen + BSD_OVHD;
1097 db->uncomp_bytes += explen;