Bug Summary

File:src/usr.bin/compress/zopen.c
Warning:line 265, column 8
Value stored to 'i' is never read

Annotated Source Code

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clang -cc1 -cc1 -triple amd64-unknown-openbsd7.0 -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name zopen.c -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -setup-static-analyzer -mrelocation-model pic -pic-level 1 -pic-is-pie -mframe-pointer=all -relaxed-aliasing -fno-rounding-math -mconstructor-aliases -munwind-tables -target-cpu x86-64 -target-feature +retpoline-indirect-calls -target-feature +retpoline-indirect-branches -tune-cpu generic -debugger-tuning=gdb -fcoverage-compilation-dir=/usr/src/usr.bin/compress/obj -resource-dir /usr/local/lib/clang/13.0.0 -internal-isystem /usr/local/lib/clang/13.0.0/include -internal-externc-isystem /usr/include -O2 -fdebug-compilation-dir=/usr/src/usr.bin/compress/obj -ferror-limit 19 -fwrapv -D_RET_PROTECTOR -ret-protector -fgnuc-version=4.2.1 -vectorize-loops -vectorize-slp -fno-builtin-malloc -fno-builtin-calloc -fno-builtin-realloc -fno-builtin-valloc -fno-builtin-free -fno-builtin-strdup -fno-builtin-strndup -analyzer-output=html -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /home/ben/Projects/vmm/scan-build/2022-01-12-194120-40624-1 -x c /usr/src/usr.bin/compress/zopen.c
1/* $OpenBSD: zopen.c,v 1.22 2017/05/29 14:41:16 fcambus Exp $ */
2/* $NetBSD: zopen.c,v 1.5 1995/03/26 09:44:53 glass Exp $ */
3
4/*-
5 * Copyright (c) 1985, 1986, 1992, 1993
6 * The Regents of the University of California. All rights reserved.
7 *
8 * This code is derived from software contributed to Berkeley by
9 * Diomidis Spinellis and James A. Woods, derived from original
10 * work by Spencer Thomas and Joseph Orost.
11 *
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
14 * are met:
15 * 1. Redistributions of source code must retain the above copyright
16 * notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 * notice, this list of conditions and the following disclaimer in the
19 * documentation and/or other materials provided with the distribution.
20 * 3. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 *
36 * From: @(#)zopen.c 8.1 (Berkeley) 6/27/93
37 */
38
39/*-
40 * fcompress.c - File compression ala IEEE Computer, June 1984.
41 *
42 * Compress authors:
43 * Spencer W. Thomas (decvax!utah-cs!thomas)
44 * Jim McKie (decvax!mcvax!jim)
45 * Steve Davies (decvax!vax135!petsd!peora!srd)
46 * Ken Turkowski (decvax!decwrl!turtlevax!ken)
47 * James A. Woods (decvax!ihnp4!ames!jaw)
48 * Joe Orost (decvax!vax135!petsd!joe)
49 *
50 * Cleaned up and converted to library returning I/O streams by
51 * Diomidis Spinellis <dds@doc.ic.ac.uk>.
52 *
53 * zopen(filename, mode, bits)
54 * Returns a FILE * that can be used for read or write. The modes
55 * supported are only "r" and "w". Seeking is not allowed. On
56 * reading the file is decompressed, on writing it is compressed.
57 * The output is compatible with compress(1) with 16 bit tables.
58 * Any file produced by compress(1) can be read.
59 */
60
61#include <sys/stat.h>
62
63#include <ctype.h>
64#include <errno(*__errno()).h>
65#include <signal.h>
66#include <stdio.h>
67#include <stdlib.h>
68#include <string.h>
69#include <unistd.h>
70#include <fcntl.h>
71#include "compress.h"
72
73#define MINIMUM(a, b)(((a) < (b)) ? (a) : (b)) (((a) < (b)) ? (a) : (b))
74
75#define BITS16 16 /* Default bits. */
76#define HSIZE69001 69001 /* 95% occupancy */
77#define ZBUFSIZ8192 8192 /* I/O buffer size */
78
79/* A code_int must be able to hold 2**BITS values of type int, and also -1. */
80typedef long code_int;
81typedef long count_int;
82
83static const u_char z_magic[] =
84 {'\037', '\235'}; /* 1F 9D */
85
86#define BIT_MASK0x1f 0x1f /* Defines for third byte of header. */
87#define BLOCK_MASK0x80 0x80
88
89/*
90 * Masks 0x40 and 0x20 are free. I think 0x20 should mean that there is
91 * a fourth header byte (for expansion).
92 */
93#define INIT_BITS9 9 /* Initial number of bits/code. */
94
95#define MAXCODE(n_bits)((1 << (n_bits)) - 1) ((1 << (n_bits)) - 1)
96
97struct s_zstate {
98 int zs_fd; /* File stream for I/O */
99 char zs_mode; /* r or w */
100 enum {
101 S_START, S_MAGIC, S_MIDDLE, S_EOF
102 } zs_state; /* State of computation */
103 int zs_n_bits; /* Number of bits/code. */
104 int zs_maxbits; /* User settable max # bits/code. */
105 code_int zs_maxcode; /* Maximum code, given n_bits. */
106 code_int zs_maxmaxcode; /* Should NEVER generate this code. */
107 count_int zs_htab[HSIZE69001];
108 u_short zs_codetab[HSIZE69001];
109 code_int zs_hsize; /* For dynamic table sizing. */
110 code_int zs_free_ent; /* First unused entry. */
111 /*
112 * Block compression parameters -- after all codes are used up,
113 * and compression rate changes, start over.
114 */
115 int zs_block_compress;
116 int zs_clear_flg;
117 long zs_ratio;
118 count_int zs_checkpoint;
119 long zs_in_count; /* Length of input. */
120 long zs_bytes_out; /* Length of output. */
121 long zs_out_count; /* # of codes output (for debugging).*/
122 u_char zs_buf[ZBUFSIZ8192]; /* I/O buffer */
123 u_char *zs_bp; /* Current I/O window in the zs_buf */
124 int zs_offset; /* Number of bits in the zs_buf */
125 union {
126 struct {
127 long zs_fcodeu.w.zs_fcode;
128 code_int zs_entu.w.zs_ent;
129 code_int zs_hsize_regu.w.zs_hsize_reg;
130 int zs_hshiftu.w.zs_hshift;
131 } w; /* Write parameters */
132 struct {
133 u_char *zs_stackpu.r.zs_stackp, *zs_ebpu.r.zs_ebp;
134 int zs_fincharu.r.zs_finchar;
135 code_int zs_codeu.r.zs_code, zs_oldcodeu.r.zs_oldcode, zs_incodeu.r.zs_incode;
136 int zs_sizeu.r.zs_size;
137 } r; /* Read parameters */
138 } u;
139};
140
141/* Definitions to retain old variable names */
142#define zs_fcodeu.w.zs_fcode u.w.zs_fcodeu.w.zs_fcode
143#define zs_entu.w.zs_ent u.w.zs_entu.w.zs_ent
144#define zs_hsize_regu.w.zs_hsize_reg u.w.zs_hsize_regu.w.zs_hsize_reg
145#define zs_hshiftu.w.zs_hshift u.w.zs_hshiftu.w.zs_hshift
146#define zs_stackpu.r.zs_stackp u.r.zs_stackpu.r.zs_stackp
147#define zs_fincharu.r.zs_finchar u.r.zs_fincharu.r.zs_finchar
148#define zs_codeu.r.zs_code u.r.zs_codeu.r.zs_code
149#define zs_oldcodeu.r.zs_oldcode u.r.zs_oldcodeu.r.zs_oldcode
150#define zs_incodeu.r.zs_incode u.r.zs_incodeu.r.zs_incode
151#define zs_sizeu.r.zs_size u.r.zs_sizeu.r.zs_size
152#define zs_ebpu.r.zs_ebp u.r.zs_ebpu.r.zs_ebp
153
154/*
155 * To save much memory, we overlay the table used by compress() with those
156 * used by decompress(). The tab_prefix table is the same size and type as
157 * the codetab. The tab_suffix table needs 2**BITS characters. We get this
158 * from the beginning of htab. The output stack uses the rest of htab, and
159 * contains characters. There is plenty of room for any possible stack
160 * (stack used to be 8000 characters).
161 */
162
163#define htabof(i)zs->zs_htab[i] zs->zs_htab[i]
164#define codetabof(i)zs->zs_codetab[i] zs->zs_codetab[i]
165
166#define tab_prefixof(i)zs->zs_codetab[i] codetabof(i)zs->zs_codetab[i]
167#define tab_suffixof(i)((u_char *)(zs->zs_htab))[i] ((u_char *)(zs->zs_htab))[i]
168#define de_stack((u_char *)&((u_char *)(zs->zs_htab))[1 << 16]) ((u_char *)&tab_suffixof(1 << BITS)((u_char *)(zs->zs_htab))[1 << 16])
169
170#define CHECK_GAP10000 10000 /* Ratio check interval. */
171
172/*
173 * the next two codes should not be changed lightly, as they must not
174 * lie within the contiguous general code space.
175 */
176#define FIRST257 257 /* First free entry. */
177#define CLEAR256 256 /* Table clear output code. */
178
179static int cl_block(struct s_zstate *);
180static void cl_hash(struct s_zstate *, count_int);
181static code_int getcode(struct s_zstate *);
182static int output(struct s_zstate *, code_int);
183
184/*-
185 * Algorithm from "A Technique for High Performance Data Compression",
186 * Terry A. Welch, IEEE Computer Vol 17, No 6 (June 1984), pp 8-19.
187 *
188 * Algorithm:
189 * Modified Lempel-Ziv method (LZW). Basically finds common
190 * substrings and replaces them with a variable size code. This is
191 * deterministic, and can be done on the fly. Thus, the decompression
192 * procedure needs no input table, but tracks the way the table was built.
193 */
194
195/*-
196 * compress write
197 *
198 * Algorithm: use open addressing double hashing (no chaining) on the
199 * prefix code / next character combination. We do a variant of Knuth's
200 * algorithm D (vol. 3, sec. 6.4) along with G. Knott's relatively-prime
201 * secondary probe. Here, the modular division first probe is gives way
202 * to a faster exclusive-or manipulation. Also do block compression with
203 * an adaptive reset, whereby the code table is cleared when the compression
204 * ratio decreases, but after the table fills. The variable-length output
205 * codes are re-sized at this point, and a special CLEAR code is generated
206 * for the decompressor. Late addition: construct the table according to
207 * file size for noticeable speed improvement on small files. Please direct
208 * questions about this implementation to ames!jaw.
209 */
210int
211zwrite(void *cookie, const char *wbp, int num)
212{
213 code_int i;
214 int c, disp;
215 struct s_zstate *zs;
216 const u_char *bp;
217 u_char tmp;
218 int count;
219
220 zs = cookie;
221 count = num;
222 bp = (u_char *)wbp;
223 switch (zs->zs_state) {
224 case S_MAGIC:
225 return -1;
226 case S_EOF:
227 return 0;
228 case S_START:
229 zs->zs_state = S_MIDDLE;
230
231 zs->zs_maxmaxcode = 1L << zs->zs_maxbits;
232 if (write(zs->zs_fd, z_magic, sizeof(z_magic)) !=
233 sizeof(z_magic))
234 return (-1);
235 tmp = (u_char)(zs->zs_maxbits | zs->zs_block_compress);
236 if (write(zs->zs_fd, &tmp, sizeof(tmp)) != sizeof(tmp))
237 return (-1);
238
239 zs->zs_bp = zs->zs_buf;
240 zs->zs_offset = 0;
241 zs->zs_bytes_out = 3; /* Includes 3-byte header mojo. */
242 zs->zs_out_count = 0;
243 zs->zs_clear_flg = 0;
244 zs->zs_ratio = 0;
245 zs->zs_in_count = 1;
246 zs->zs_checkpoint = CHECK_GAP10000;
247 zs->zs_maxcode = MAXCODE(zs->zs_n_bits = INIT_BITS)((1 << (zs->zs_n_bits = 9)) - 1);
248 zs->zs_free_ent = ((zs->zs_block_compress) ? FIRST257 : 256);
249
250 zs->zs_entu.w.zs_ent = *bp++;
251 --count;
252
253 zs->zs_hshiftu.w.zs_hshift = 0;
254 for (zs->zs_fcodeu.w.zs_fcode = (long)zs->zs_hsize; zs->zs_fcodeu.w.zs_fcode < 65536L;
255 zs->zs_fcodeu.w.zs_fcode *= 2L)
256 zs->zs_hshiftu.w.zs_hshift++;
257 /* Set hash code range bound. */
258 zs->zs_hshiftu.w.zs_hshift = 8 - zs->zs_hshiftu.w.zs_hshift;
259
260 zs->zs_hsize_regu.w.zs_hsize_reg = zs->zs_hsize;
261 /* Clear hash table. */
262 cl_hash(zs, (count_int)zs->zs_hsize_regu.w.zs_hsize_reg);
263
264 case S_MIDDLE:
265 for (i = 0; count-- > 0;) {
Value stored to 'i' is never read
266 c = *bp++;
267 zs->zs_in_count++;
268 zs->zs_fcodeu.w.zs_fcode = (long)(((long)c << zs->zs_maxbits) +
269 zs->zs_entu.w.zs_ent);
270 /* Xor hashing. */
271 i = ((c << zs->zs_hshiftu.w.zs_hshift) ^ zs->zs_entu.w.zs_ent);
272
273 if (htabof(i)zs->zs_htab[i] == zs->zs_fcodeu.w.zs_fcode) {
274 zs->zs_entu.w.zs_ent = codetabof(i)zs->zs_codetab[i];
275 continue;
276 } else if ((long)htabof(i)zs->zs_htab[i] < 0) /* Empty slot. */
277 goto nomatch;
278 /* Secondary hash (after G. Knott). */
279 disp = zs->zs_hsize_regu.w.zs_hsize_reg - i;
280 if (i == 0)
281 disp = 1;
282probe: if ((i -= disp) < 0)
283 i += zs->zs_hsize_regu.w.zs_hsize_reg;
284
285 if (htabof(i)zs->zs_htab[i] == zs->zs_fcodeu.w.zs_fcode) {
286 zs->zs_entu.w.zs_ent = codetabof(i)zs->zs_codetab[i];
287 continue;
288 }
289 if ((long)htabof(i)zs->zs_htab[i] >= 0)
290 goto probe;
291nomatch: if (output(zs, (code_int) zs->zs_entu.w.zs_ent) == -1)
292 return (-1);
293 zs->zs_out_count++;
294 zs->zs_entu.w.zs_ent = c;
295 if (zs->zs_free_ent < zs->zs_maxmaxcode) {
296 /* code -> hashtable */
297 codetabof(i)zs->zs_codetab[i] = zs->zs_free_ent++;
298 htabof(i)zs->zs_htab[i] = zs->zs_fcodeu.w.zs_fcode;
299 } else if ((count_int)zs->zs_in_count >=
300 zs->zs_checkpoint && zs->zs_block_compress) {
301 if (cl_block(zs) == -1)
302 return (-1);
303 }
304 }
305 }
306 return (num);
307}
308
309int
310z_close(void *cookie, struct z_info *info, const char *name, struct stat *sb)
311{
312 struct s_zstate *zs;
313 int rval;
314
315 zs = cookie;
316 if (zs->zs_mode == 'w') { /* Put out the final code. */
317 if (output(zs, (code_int) zs->zs_entu.w.zs_ent) == -1) {
318 (void)close(zs->zs_fd);
319 free(zs);
320 return (-1);
321 }
322 zs->zs_out_count++;
323 if (output(zs, (code_int) - 1) == -1) {
324 (void)close(zs->zs_fd);
325 free(zs);
326 return (-1);
327 }
328 }
329
330 if (info != NULL((void *)0)) {
331 info->mtime = 0;
332 info->crc = (u_int32_t)-1;
333 info->hlen = 0;
334 info->total_in = (off_t)zs->zs_in_count;
335 info->total_out = (off_t)zs->zs_bytes_out;
336 }
337
338#ifndef SAVECORE
339 setfile(name, zs->zs_fd, sb);
340#endif
341 rval = close(zs->zs_fd);
342 free(zs);
343 return (rval);
344}
345
346/*-
347 * Output the given code.
348 * Inputs:
349 * code: A n_bits-bit integer. If == -1, then EOF. This assumes
350 * that n_bits =< (long)wordsize - 1.
351 * Outputs:
352 * Outputs code to the file.
353 * Assumptions:
354 * Chars are 8 bits long.
355 * Algorithm:
356 * Maintain a BITS character long buffer (so that 8 codes will
357 * fit in it exactly). Use the VAX insv instruction to insert each
358 * code in turn. When the buffer fills up empty it and start over.
359 */
360
361static const u_char lmask[9] =
362 {0xff, 0xfe, 0xfc, 0xf8, 0xf0, 0xe0, 0xc0, 0x80, 0x00};
363static const u_char rmask[9] =
364 {0x00, 0x01, 0x03, 0x07, 0x0f, 0x1f, 0x3f, 0x7f, 0xff};
365
366static int
367output(struct s_zstate *zs, code_int ocode)
368{
369 int bits;
370
371 if (ocode >= 0) {
372 int r_off;
373 u_char *bp;
374
375 /* Get to the first byte. */
376 bp = zs->zs_bp + (zs->zs_offset >> 3);
377 r_off = zs->zs_offset & 7;
378 bits = zs->zs_n_bits;
379
380 /*
381 * Since ocode is always >= 8 bits, only need to mask the first
382 * hunk on the left.
383 */
384 *bp = (*bp & rmask[r_off]) | ((ocode << r_off) & lmask[r_off]);
385 bp++;
386 bits -= (8 - r_off);
387 ocode >>= 8 - r_off;
388 /* Get any 8 bit parts in the middle (<=1 for up to 16 bits) */
389 if (bits >= 8) {
390 *bp++ = ocode;
391 ocode >>= 8;
392 bits -= 8;
393 }
394 /* Last bits. */
395 if (bits)
396 *bp = ocode;
397 zs->zs_offset += zs->zs_n_bits;
398 if (zs->zs_offset == (zs->zs_n_bits << 3)) {
399 zs->zs_bp += zs->zs_n_bits;
400 zs->zs_offset = 0;
401 }
402 /*
403 * If the next entry is going to be too big for the ocode size,
404 * then increase it, if possible.
405 */
406 if (zs->zs_free_ent > zs->zs_maxcode ||
407 (zs->zs_clear_flg > 0)) {
408 /*
409 * Write the whole buffer, because the input side won't
410 * discover the size increase until after it has read it
411 */
412 if (zs->zs_offset > 0) {
413 zs->zs_bp += zs->zs_n_bits;
414 zs->zs_offset = 0;
415 }
416
417 if (zs->zs_clear_flg) {
418 zs->zs_maxcode =
419 MAXCODE(zs->zs_n_bits = INIT_BITS)((1 << (zs->zs_n_bits = 9)) - 1);
420 zs->zs_clear_flg = 0;
421 } else {
422 zs->zs_n_bits++;
423 if (zs->zs_n_bits == zs->zs_maxbits)
424 zs->zs_maxcode = zs->zs_maxmaxcode;
425 else
426 zs->zs_maxcode =
427 MAXCODE(zs->zs_n_bits)((1 << (zs->zs_n_bits)) - 1);
428 }
429 }
430
431 if (zs->zs_bp + zs->zs_n_bits > &zs->zs_buf[ZBUFSIZ8192]) {
432 bits = zs->zs_bp - zs->zs_buf;
433 if (write(zs->zs_fd, zs->zs_buf, bits) != bits)
434 return (-1);
435 zs->zs_bytes_out += bits;
436 if (zs->zs_offset > 0)
437 fprintf (stderr(&__sF[2]), "zs_offset != 0\n");
438 zs->zs_bp = zs->zs_buf;
439 }
440 } else {
441 /* At EOF, write the rest of the buffer. */
442 if (zs->zs_offset > 0)
443 zs->zs_bp += (zs->zs_offset + 7) / 8;
444 if (zs->zs_bp > zs->zs_buf) {
445 bits = zs->zs_bp - zs->zs_buf;
446 if (write(zs->zs_fd, zs->zs_buf, bits) != bits)
447 return (-1);
448 zs->zs_bytes_out += bits;
449 }
450 zs->zs_offset = 0;
451 zs->zs_bp = zs->zs_buf;
452 }
453 return (0);
454}
455
456/*
457 * Decompress read. This routine adapts to the codes in the file building
458 * the "string" table on-the-fly; requiring no table to be stored in the
459 * compressed file. The tables used herein are shared with those of the
460 * compress() routine. See the definitions above.
461 */
462int
463zread(void *cookie, char *rbp, int num)
464{
465 u_int count;
466 struct s_zstate *zs;
467 u_char *bp, header[3];
468
469 if (num == 0)
470 return (0);
471
472 zs = cookie;
473 count = num;
474 bp = (u_char *)rbp;
475 switch (zs->zs_state) {
476 case S_START:
477 zs->zs_state = S_MIDDLE;
478 zs->zs_bp = zs->zs_buf;
479 header[0] = header[1] = header[2] = '\0';
480 read(zs->zs_fd, header, sizeof(header));
481 break;
482 case S_MAGIC:
483 zs->zs_state = S_MIDDLE;
484 zs->zs_bp = zs->zs_buf;
485 header[0] = z_magic[0];
486 header[1] = z_magic[1];
487 header[2] = '\0';
488 read(zs->zs_fd, &header[2], 1);
489 break;
490 case S_MIDDLE:
491 goto middle;
492 case S_EOF:
493 goto eof;
494 }
495
496 /* Check the magic number */
497 if (header[0] != z_magic[0] || header[1] != z_magic[1]) {
498 errno(*__errno()) = EFTYPE79;
499 return (-1);
500 }
501 zs->zs_maxbits = header[2]; /* Set -b from file. */
502 zs->zs_in_count += sizeof(header);
503 zs->zs_block_compress = zs->zs_maxbits & BLOCK_MASK0x80;
504 zs->zs_maxbits &= BIT_MASK0x1f;
505 zs->zs_maxmaxcode = 1L << zs->zs_maxbits;
506 if (zs->zs_maxbits > BITS16) {
507 errno(*__errno()) = EFTYPE79;
508 return (-1);
509 }
510 /* As above, initialize the first 256 entries in the table. */
511 zs->zs_maxcode = MAXCODE(zs->zs_n_bits = INIT_BITS)((1 << (zs->zs_n_bits = 9)) - 1);
512 for (zs->zs_codeu.r.zs_code = 255; zs->zs_codeu.r.zs_code >= 0; zs->zs_codeu.r.zs_code--) {
513 tab_prefixof(zs->zs_code)zs->zs_codetab[zs->u.r.zs_code] = 0;
514 tab_suffixof(zs->zs_code)((u_char *)(zs->zs_htab))[zs->u.r.zs_code] = (u_char) zs->zs_codeu.r.zs_code;
515 }
516 zs->zs_free_ent = zs->zs_block_compress ? FIRST257 : 256;
517
518 zs->zs_fincharu.r.zs_finchar = zs->zs_oldcodeu.r.zs_oldcode = getcode(zs);
519 if (zs->zs_oldcodeu.r.zs_oldcode == -1) /* EOF already? */
520 return (0); /* Get out of here */
521
522 /* First code must be 8 bits = char. */
523 *bp++ = (u_char)zs->zs_fincharu.r.zs_finchar;
524 count--;
525 zs->zs_stackpu.r.zs_stackp = de_stack((u_char *)&((u_char *)(zs->zs_htab))[1 << 16]);
526
527 while ((zs->zs_codeu.r.zs_code = getcode(zs)) > -1) {
528
529 if ((zs->zs_codeu.r.zs_code == CLEAR256) && zs->zs_block_compress) {
530 for (zs->zs_codeu.r.zs_code = 255; zs->zs_codeu.r.zs_code >= 0;
531 zs->zs_codeu.r.zs_code--)
532 tab_prefixof(zs->zs_code)zs->zs_codetab[zs->u.r.zs_code] = 0;
533 zs->zs_clear_flg = 1;
534 zs->zs_free_ent = FIRST257 - 1;
535 if ((zs->zs_codeu.r.zs_code = getcode(zs)) == -1) /* O, untimely death! */
536 break;
537 }
538 zs->zs_incodeu.r.zs_incode = zs->zs_codeu.r.zs_code;
539
540 /* Special case for KwKwK string. */
541 if (zs->zs_codeu.r.zs_code >= zs->zs_free_ent) {
542 *zs->zs_stackpu.r.zs_stackp++ = zs->zs_fincharu.r.zs_finchar;
543 zs->zs_codeu.r.zs_code = zs->zs_oldcodeu.r.zs_oldcode;
544 }
545
546 /* Generate output characters in reverse order. */
547 while (zs->zs_codeu.r.zs_code >= 256) {
548 /*
549 * Bad input file may cause zs_stackp to overflow
550 * zs_htab; check here and abort decompression,
551 * that's better than dumping core.
552 */
553 if (zs->zs_stackpu.r.zs_stackp >= (u_char *)&zs->zs_htab[HSIZE69001]) {
554 errno(*__errno()) = EINVAL22;
555 return (-1);
556 }
557 *zs->zs_stackpu.r.zs_stackp++ = tab_suffixof(zs->zs_code)((u_char *)(zs->zs_htab))[zs->u.r.zs_code];
558 zs->zs_codeu.r.zs_code = tab_prefixof(zs->zs_code)zs->zs_codetab[zs->u.r.zs_code];
559 }
560 *zs->zs_stackpu.r.zs_stackp++ = zs->zs_fincharu.r.zs_finchar = tab_suffixof(zs->zs_code)((u_char *)(zs->zs_htab))[zs->u.r.zs_code];
561
562 /* And put them out in forward order. */
563middle: do {
564 if (count-- == 0) {
565 zs->zs_bytes_out += num;
566 return (num);
567 }
568 *bp++ = *--zs->zs_stackpu.r.zs_stackp;
569 } while (zs->zs_stackpu.r.zs_stackp > de_stack((u_char *)&((u_char *)(zs->zs_htab))[1 << 16]));
570
571 /* Generate the new entry. */
572 if ((zs->zs_codeu.r.zs_code = zs->zs_free_ent) < zs->zs_maxmaxcode) {
573 tab_prefixof(zs->zs_code)zs->zs_codetab[zs->u.r.zs_code] = (u_short) zs->zs_oldcodeu.r.zs_oldcode;
574 tab_suffixof(zs->zs_code)((u_char *)(zs->zs_htab))[zs->u.r.zs_code] = zs->zs_fincharu.r.zs_finchar;
575 zs->zs_free_ent = zs->zs_codeu.r.zs_code + 1;
576 }
577
578 /* Remember previous code. */
579 zs->zs_oldcodeu.r.zs_oldcode = zs->zs_incodeu.r.zs_incode;
580 }
581 zs->zs_state = S_EOF;
582 zs->zs_bytes_out += num - count;
583eof: return (num - count);
584}
585
586/*-
587 * Read one code from the standard input. If EOF, return -1.
588 * Inputs:
589 * stdin
590 * Outputs:
591 * code or -1 is returned.
592 */
593static code_int
594getcode(struct s_zstate *zs)
595{
596 code_int gcode;
597 int r_off, bits;
598 u_char *bp;
599
600 if (zs->zs_clear_flg > 0 || zs->zs_offset >= zs->zs_sizeu.r.zs_size ||
601 zs->zs_free_ent > zs->zs_maxcode) {
602
603 zs->zs_bp += zs->zs_n_bits;
604 /*
605 * If the next entry will be too big for the current gcode
606 * size, then we must increase the size. This implies reading
607 * a new buffer full, too.
608 */
609 if (zs->zs_free_ent > zs->zs_maxcode) {
610 zs->zs_n_bits++;
611 if (zs->zs_n_bits == zs->zs_maxbits) {
612 /* Won't get any bigger now. */
613 zs->zs_maxcode = zs->zs_maxmaxcode;
614 } else
615 zs->zs_maxcode = MAXCODE(zs->zs_n_bits)((1 << (zs->zs_n_bits)) - 1);
616 }
617 if (zs->zs_clear_flg > 0) {
618 zs->zs_maxcode = MAXCODE(zs->zs_n_bits = INIT_BITS)((1 << (zs->zs_n_bits = 9)) - 1);
619 zs->zs_clear_flg = 0;
620 }
621
622 /* fill the buffer up to the neck */
623 if (zs->zs_bp + zs->zs_n_bits > zs->zs_ebpu.r.zs_ebp) {
624 for (bp = zs->zs_buf; zs->zs_bp < zs->zs_ebpu.r.zs_ebp;
625 *bp++ = *zs->zs_bp++);
626 if ((bits = read(zs->zs_fd, bp, ZBUFSIZ8192 -
627 (bp - zs->zs_buf))) < 0)
628 return -1;
629 zs->zs_in_count += bits;
630 zs->zs_bp = zs->zs_buf;
631 zs->zs_ebpu.r.zs_ebp = bp + bits;
632 }
633 zs->zs_offset = 0;
634 zs->zs_sizeu.r.zs_size = MINIMUM(zs->zs_n_bits, zs->zs_ebp - zs->zs_bp)(((zs->zs_n_bits) < (zs->u.r.zs_ebp - zs->zs_bp))
? (zs->zs_n_bits) : (zs->u.r.zs_ebp - zs->zs_bp));
635 if (zs->zs_sizeu.r.zs_size == 0)
636 return -1;
637 /* Round size down to integral number of codes. */
638 zs->zs_sizeu.r.zs_size = (zs->zs_sizeu.r.zs_size << 3) - (zs->zs_n_bits - 1);
639 }
640
641 bp = zs->zs_bp;
642 r_off = zs->zs_offset;
643 bits = zs->zs_n_bits;
644
645 /* Get to the first byte. */
646 bp += (r_off >> 3);
647 r_off &= 7;
648
649 /* Get first part (low order bits). */
650 gcode = (*bp++ >> r_off);
651 bits -= (8 - r_off);
652 r_off = 8 - r_off; /* Now, roffset into gcode word. */
653
654 /* Get any 8 bit parts in the middle (<=1 for up to 16 bits). */
655 if (bits >= 8) {
656 gcode |= *bp++ << r_off;
657 r_off += 8;
658 bits -= 8;
659 }
660
661 /* High order bits. */
662 gcode |= (*bp & rmask[bits]) << r_off;
663 zs->zs_offset += zs->zs_n_bits;
664
665 return (gcode);
666}
667
668/* Table clear for block compress. */
669static int
670cl_block(struct s_zstate *zs)
671{
672 long rat;
673
674 zs->zs_checkpoint = zs->zs_in_count + CHECK_GAP10000;
675
676 if (zs->zs_in_count > 0x007fffff) { /* Shift will overflow. */
677 rat = zs->zs_bytes_out >> 8;
678 if (rat == 0) /* Don't divide by zero. */
679 rat = 0x7fffffff;
680 else
681 rat = zs->zs_in_count / rat;
682 } else {
683 /* 8 fractional bits. */
684 rat = (zs->zs_in_count << 8) / zs->zs_bytes_out;
685 }
686 if (rat > zs->zs_ratio)
687 zs->zs_ratio = rat;
688 else {
689 zs->zs_ratio = 0;
690 cl_hash(zs, (count_int) zs->zs_hsize);
691 zs->zs_free_ent = FIRST257;
692 zs->zs_clear_flg = 1;
693 if (output(zs, (code_int) CLEAR256) == -1)
694 return (-1);
695 }
696 return (0);
697}
698
699/* Reset code table. */
700static void
701cl_hash(struct s_zstate *zs, count_int cl_hsize)
702{
703 count_int *htab_p;
704 long i, m1;
705
706 m1 = -1;
707 htab_p = zs->zs_htab + cl_hsize;
708 i = cl_hsize - 16;
709 do { /* Might use Sys V memset(3) here. */
710 *(htab_p - 16) = m1;
711 *(htab_p - 15) = m1;
712 *(htab_p - 14) = m1;
713 *(htab_p - 13) = m1;
714 *(htab_p - 12) = m1;
715 *(htab_p - 11) = m1;
716 *(htab_p - 10) = m1;
717 *(htab_p - 9) = m1;
718 *(htab_p - 8) = m1;
719 *(htab_p - 7) = m1;
720 *(htab_p - 6) = m1;
721 *(htab_p - 5) = m1;
722 *(htab_p - 4) = m1;
723 *(htab_p - 3) = m1;
724 *(htab_p - 2) = m1;
725 *(htab_p - 1) = m1;
726 htab_p -= 16;
727 } while ((i -= 16) >= 0);
728 for (i += 16; i > 0; i--)
729 *--htab_p = m1;
730}
731
732void *
733z_wopen(int fd, char *name, int bits, u_int32_t mtime)
734{
735 struct s_zstate *zs;
736
737 if (bits < 0 || bits > BITS16) {
738 errno(*__errno()) = EINVAL22;
739 return (NULL((void *)0));
740 }
741
742 if ((zs = calloc(1, sizeof(struct s_zstate))) == NULL((void *)0))
743 return (NULL((void *)0));
744
745 /* User settable max # bits/code. */
746 zs->zs_maxbits = bits ? bits : BITS16;
747 /* Should NEVER generate this code. */
748 zs->zs_maxmaxcode = 1 << zs->zs_maxbits;
749 zs->zs_hsize = HSIZE69001; /* For dynamic table sizing. */
750 zs->zs_free_ent = 0; /* First unused entry. */
751 zs->zs_block_compress = BLOCK_MASK0x80;
752 zs->zs_clear_flg = 0;
753 zs->zs_ratio = 0;
754 zs->zs_checkpoint = CHECK_GAP10000;
755 zs->zs_in_count = 0; /* Length of input. */
756 zs->zs_out_count = 0; /* # of codes output (for debugging).*/
757 zs->zs_state = S_START;
758 zs->zs_offset = 0;
759 zs->zs_sizeu.r.zs_size = 0;
760 zs->zs_mode = 'w';
761 zs->zs_bp = zs->zs_ebpu.r.zs_ebp = zs->zs_buf;
762
763 zs->zs_fd = fd;
764 return zs;
765}
766
767void *
768z_ropen(int fd, char *name, int gotmagic)
769{
770 struct s_zstate *zs;
771
772 if ((zs = calloc(1, sizeof(struct s_zstate))) == NULL((void *)0))
773 return (NULL((void *)0));
774
775 /* User settable max # bits/code. */
776 zs->zs_maxbits = BITS16;
777 /* Should NEVER generate this code. */
778 zs->zs_maxmaxcode = 1 << zs->zs_maxbits;
779 zs->zs_hsize = HSIZE69001; /* For dynamic table sizing. */
780 zs->zs_free_ent = 0; /* First unused entry. */
781 zs->zs_block_compress = BLOCK_MASK0x80;
782 zs->zs_clear_flg = 0;
783 zs->zs_ratio = 0;
784 zs->zs_checkpoint = CHECK_GAP10000;
785 zs->zs_in_count = 0; /* Length of input. */
786 zs->zs_out_count = 0; /* # of codes output (for debugging).*/
787 zs->zs_state = gotmagic ? S_MAGIC : S_START;
788 zs->zs_offset = 0;
789 zs->zs_sizeu.r.zs_size = 0;
790 zs->zs_mode = 'r';
791 zs->zs_bp = zs->zs_ebpu.r.zs_ebp = zs->zs_buf;
792
793 zs->zs_fd = fd;
794 return zs;
795}