Annotation of src/usr.bin/compress/zopen.c, Revision 1.17
1.17 ! millert 1: /* $OpenBSD: zopen.c,v 1.16 2005/06/26 18:20:26 otto Exp $ */
1.1 deraadt 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.
1.10 millert 20: * 3. Neither the name of the University nor the names of its contributors
1.1 deraadt 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.
1.9 mickey 35: *
36: * From: @(#)zopen.c 8.1 (Berkeley) 6/27/93
1.1 deraadt 37: */
38:
39: #if 0
40: static char sccsid[] = "@(#)zopen.c 8.1 (Berkeley) 6/27/93";
41: #else
1.9 mickey 42: const char z_rcsid[] =
1.17 ! millert 43: "$OpenBSD: zopen.c,v 1.16 2005/06/26 18:20:26 otto Exp $";
1.1 deraadt 44: #endif
45:
46: /*-
47: * fcompress.c - File compression ala IEEE Computer, June 1984.
48: *
49: * Compress authors:
50: * Spencer W. Thomas (decvax!utah-cs!thomas)
51: * Jim McKie (decvax!mcvax!jim)
52: * Steve Davies (decvax!vax135!petsd!peora!srd)
53: * Ken Turkowski (decvax!decwrl!turtlevax!ken)
54: * James A. Woods (decvax!ihnp4!ames!jaw)
55: * Joe Orost (decvax!vax135!petsd!joe)
56: *
57: * Cleaned up and converted to library returning I/O streams by
58: * Diomidis Spinellis <dds@doc.ic.ac.uk>.
59: *
60: * zopen(filename, mode, bits)
61: * Returns a FILE * that can be used for read or write. The modes
62: * supported are only "r" and "w". Seeking is not allowed. On
63: * reading the file is decompressed, on writing it is compressed.
64: * The output is compatible with compress(1) with 16 bit tables.
65: * Any file produced by compress(1) can be read.
66: */
67:
68: #include <sys/param.h>
69: #include <sys/stat.h>
70:
71: #include <ctype.h>
72: #include <errno.h>
73: #include <signal.h>
74: #include <stdio.h>
75: #include <stdlib.h>
76: #include <string.h>
77: #include <unistd.h>
1.5 mickey 78: #include <fcntl.h>
79: #include "compress.h"
1.1 deraadt 80:
81: #define BITS 16 /* Default bits. */
82: #define HSIZE 69001 /* 95% occupancy */
1.6 mickey 83: #define ZBUFSIZ 8192 /* I/O buffer size */
1.1 deraadt 84:
85: /* A code_int must be able to hold 2**BITS values of type int, and also -1. */
86: typedef long code_int;
87: typedef long count_int;
88:
1.9 mickey 89: static const u_char z_magic[] =
1.1 deraadt 90: {'\037', '\235'}; /* 1F 9D */
91:
92: #define BIT_MASK 0x1f /* Defines for third byte of header. */
93: #define BLOCK_MASK 0x80
94:
95: /*
96: * Masks 0x40 and 0x20 are free. I think 0x20 should mean that there is
97: * a fourth header byte (for expansion).
98: */
99: #define INIT_BITS 9 /* Initial number of bits/code. */
100:
101: #define MAXCODE(n_bits) ((1 << (n_bits)) - 1)
102:
103: struct s_zstate {
1.5 mickey 104: int zs_fd; /* File stream for I/O */
1.1 deraadt 105: char zs_mode; /* r or w */
106: enum {
1.12 millert 107: S_START, S_MAGIC, S_MIDDLE, S_EOF
1.1 deraadt 108: } zs_state; /* State of computation */
109: int zs_n_bits; /* Number of bits/code. */
110: int zs_maxbits; /* User settable max # bits/code. */
111: code_int zs_maxcode; /* Maximum code, given n_bits. */
112: code_int zs_maxmaxcode; /* Should NEVER generate this code. */
1.17 ! millert 113: count_int zs_htab[HSIZE];
! 114: u_short zs_codetab[HSIZE];
1.1 deraadt 115: code_int zs_hsize; /* For dynamic table sizing. */
116: code_int zs_free_ent; /* First unused entry. */
117: /*
118: * Block compression parameters -- after all codes are used up,
119: * and compression rate changes, start over.
120: */
121: int zs_block_compress;
122: int zs_clear_flg;
123: long zs_ratio;
124: count_int zs_checkpoint;
125: long zs_in_count; /* Length of input. */
1.13 millert 126: long zs_bytes_out; /* Length of output. */
1.5 mickey 127: long zs_out_count; /* # of codes output (for debugging).*/
1.6 mickey 128: u_char zs_buf[ZBUFSIZ]; /* I/O buffer */
129: u_char *zs_bp; /* Current I/O window in the zs_buf */
130: int zs_offset; /* Number of bits in the zs_buf */
1.1 deraadt 131: union {
132: struct {
133: long zs_fcode;
134: code_int zs_ent;
135: code_int zs_hsize_reg;
136: int zs_hshift;
1.17 ! millert 137: } w; /* Write parameters */
1.1 deraadt 138: struct {
1.6 mickey 139: u_char *zs_stackp, *zs_ebp;
1.1 deraadt 140: int zs_finchar;
141: code_int zs_code, zs_oldcode, zs_incode;
1.6 mickey 142: int zs_size;
1.1 deraadt 143: } r; /* Read parameters */
144: } u;
145: };
146:
147: /* Definitions to retain old variable names */
1.5 mickey 148: #define zs_fcode u.w.zs_fcode
149: #define zs_ent u.w.zs_ent
150: #define zs_hsize_reg u.w.zs_hsize_reg
151: #define zs_hshift u.w.zs_hshift
152: #define zs_stackp u.r.zs_stackp
153: #define zs_finchar u.r.zs_finchar
154: #define zs_code u.r.zs_code
155: #define zs_oldcode u.r.zs_oldcode
156: #define zs_incode u.r.zs_incode
157: #define zs_size u.r.zs_size
1.6 mickey 158: #define zs_ebp u.r.zs_ebp
1.1 deraadt 159:
160: /*
161: * To save much memory, we overlay the table used by compress() with those
162: * used by decompress(). The tab_prefix table is the same size and type as
163: * the codetab. The tab_suffix table needs 2**BITS characters. We get this
164: * from the beginning of htab. The output stack uses the rest of htab, and
165: * contains characters. There is plenty of room for any possible stack
166: * (stack used to be 8000 characters).
167: */
168:
1.5 mickey 169: #define htabof(i) zs->zs_htab[i]
170: #define codetabof(i) zs->zs_codetab[i]
1.1 deraadt 171:
172: #define tab_prefixof(i) codetabof(i)
1.5 mickey 173: #define tab_suffixof(i) ((u_char *)(zs->zs_htab))[i]
174: #define de_stack ((u_char *)&tab_suffixof(1 << BITS))
1.1 deraadt 175:
176: #define CHECK_GAP 10000 /* Ratio check interval. */
177:
178: /*
179: * the next two codes should not be changed lightly, as they must not
180: * lie within the contiguous general code space.
181: */
182: #define FIRST 257 /* First free entry. */
183: #define CLEAR 256 /* Table clear output code. */
184:
1.8 millert 185: static int cl_block(struct s_zstate *);
1.9 mickey 186: static void cl_hash(struct s_zstate *, count_int);
1.8 millert 187: static code_int getcode(struct s_zstate *);
188: static int output(struct s_zstate *, code_int);
1.1 deraadt 189:
190: /*-
191: * Algorithm from "A Technique for High Performance Data Compression",
192: * Terry A. Welch, IEEE Computer Vol 17, No 6 (June 1984), pp 8-19.
193: *
194: * Algorithm:
1.9 mickey 195: * Modified Lempel-Ziv method (LZW). Basically finds common
1.1 deraadt 196: * substrings and replaces them with a variable size code. This is
197: * deterministic, and can be done on the fly. Thus, the decompression
198: * procedure needs no input table, but tracks the way the table was built.
199: */
200:
201: /*-
202: * compress write
203: *
204: * Algorithm: use open addressing double hashing (no chaining) on the
205: * prefix code / next character combination. We do a variant of Knuth's
206: * algorithm D (vol. 3, sec. 6.4) along with G. Knott's relatively-prime
207: * secondary probe. Here, the modular division first probe is gives way
208: * to a faster exclusive-or manipulation. Also do block compression with
209: * an adaptive reset, whereby the code table is cleared when the compression
210: * ratio decreases, but after the table fills. The variable-length output
211: * codes are re-sized at this point, and a special CLEAR code is generated
212: * for the decompressor. Late addition: construct the table according to
213: * file size for noticeable speed improvement on small files. Please direct
214: * questions about this implementation to ames!jaw.
215: */
1.5 mickey 216: int
1.11 deraadt 217: zwrite(void *cookie, const char *wbp, int num)
1.1 deraadt 218: {
1.7 mpech 219: code_int i;
220: int c, disp;
1.1 deraadt 221: struct s_zstate *zs;
222: const u_char *bp;
223: u_char tmp;
224: int count;
225:
226: zs = cookie;
227: count = num;
228: bp = (u_char *)wbp;
1.6 mickey 229: switch (zs->zs_state) {
1.12 millert 230: case S_MAGIC:
231: return -1;
1.6 mickey 232: case S_EOF:
233: return 0;
234: case S_START:
235: zs->zs_state = S_MIDDLE;
1.1 deraadt 236:
1.6 mickey 237: zs->zs_maxmaxcode = 1L << zs->zs_maxbits;
238: if (write(zs->zs_fd, z_magic, sizeof(z_magic)) !=
239: sizeof(z_magic))
240: return (-1);
241: tmp = (u_char)(zs->zs_maxbits | zs->zs_block_compress);
242: if (write(zs->zs_fd, &tmp, sizeof(tmp)) != sizeof(tmp))
243: return (-1);
1.1 deraadt 244:
1.6 mickey 245: zs->zs_bp = zs->zs_buf;
246: zs->zs_offset = 0;
247: zs->zs_bytes_out = 3; /* Includes 3-byte header mojo. */
248: zs->zs_out_count = 0;
249: zs->zs_clear_flg = 0;
250: zs->zs_ratio = 0;
251: zs->zs_in_count = 1;
252: zs->zs_checkpoint = CHECK_GAP;
253: zs->zs_maxcode = MAXCODE(zs->zs_n_bits = INIT_BITS);
254: zs->zs_free_ent = ((zs->zs_block_compress) ? FIRST : 256);
255:
256: zs->zs_ent = *bp++;
257: --count;
258:
259: zs->zs_hshift = 0;
260: for (zs->zs_fcode = (long)zs->zs_hsize; zs->zs_fcode < 65536L;
1.11 deraadt 261: zs->zs_fcode *= 2L)
1.6 mickey 262: zs->zs_hshift++;
263: /* Set hash code range bound. */
264: zs->zs_hshift = 8 - zs->zs_hshift;
265:
266: zs->zs_hsize_reg = zs->zs_hsize;
267: /* Clear hash table. */
268: cl_hash(zs, (count_int)zs->zs_hsize_reg);
1.1 deraadt 269:
1.6 mickey 270: case S_MIDDLE:
271: for (i = 0; count-- > 0;) {
272: c = *bp++;
273: zs->zs_in_count++;
274: zs->zs_fcode = (long)(((long)c << zs->zs_maxbits) +
1.11 deraadt 275: zs->zs_ent);
1.6 mickey 276: /* Xor hashing. */
277: i = ((c << zs->zs_hshift) ^ zs->zs_ent);
1.9 mickey 278:
1.6 mickey 279: if (htabof(i) == zs->zs_fcode) {
280: zs->zs_ent = codetabof(i);
281: continue;
282: } else if ((long)htabof(i) < 0) /* Empty slot. */
283: goto nomatch;
284: /* Secondary hash (after G. Knott). */
285: disp = zs->zs_hsize_reg - i;
286: if (i == 0)
1.1 deraadt 287: disp = 1;
1.6 mickey 288: probe: if ((i -= disp) < 0)
289: i += zs->zs_hsize_reg;
1.1 deraadt 290:
1.6 mickey 291: if (htabof(i) == zs->zs_fcode) {
292: zs->zs_ent = codetabof(i);
293: continue;
294: }
295: if ((long)htabof(i) >= 0)
296: goto probe;
297: nomatch: if (output(zs, (code_int) zs->zs_ent) == -1)
1.1 deraadt 298: return (-1);
1.6 mickey 299: zs->zs_out_count++;
300: zs->zs_ent = c;
301: if (zs->zs_free_ent < zs->zs_maxmaxcode) {
302: /* code -> hashtable */
303: codetabof(i) = zs->zs_free_ent++;
304: htabof(i) = zs->zs_fcode;
305: } else if ((count_int)zs->zs_in_count >=
306: zs->zs_checkpoint && zs->zs_block_compress) {
307: if (cl_block(zs) == -1)
308: return (-1);
309: }
1.1 deraadt 310: }
311: }
312: return (num);
313: }
314:
1.5 mickey 315: int
1.16 otto 316: z_close(void *cookie, struct z_info *info, const char *name, struct stat *sb)
1.1 deraadt 317: {
318: struct s_zstate *zs;
319: int rval;
320:
321: zs = cookie;
1.5 mickey 322: if (zs->zs_mode == 'w') { /* Put out the final code. */
323: if (output(zs, (code_int) zs->zs_ent) == -1) {
324: (void)close(zs->zs_fd);
1.1 deraadt 325: free(zs);
326: return (-1);
327: }
1.5 mickey 328: zs->zs_out_count++;
1.1 deraadt 329: if (output(zs, (code_int) - 1) == -1) {
1.5 mickey 330: (void)close(zs->zs_fd);
1.1 deraadt 331: free(zs);
332: return (-1);
333: }
334: }
1.13 millert 335:
336: if (info != NULL) {
337: info->mtime = 0;
338: info->crc = (u_int32_t)-1;
339: info->hlen = 0;
340: info->total_in = (off_t)zs->zs_in_count;
341: info->total_out = (off_t)zs->zs_bytes_out;
342: }
343:
1.16 otto 344: #ifndef SAVECORE
345: setfile(name, zs->zs_fd, sb);
346: #endif
1.5 mickey 347: rval = close(zs->zs_fd);
1.1 deraadt 348: free(zs);
349: return (rval);
350: }
351:
1.14 deraadt 352: static int
1.13 millert 353: zclose(void *cookie)
354: {
1.16 otto 355: return z_close(cookie, NULL, NULL, NULL);
1.13 millert 356: }
357:
1.1 deraadt 358: /*-
359: * Output the given code.
360: * Inputs:
1.9 mickey 361: * code: A n_bits-bit integer. If == -1, then EOF. This assumes
1.1 deraadt 362: * that n_bits =< (long)wordsize - 1.
363: * Outputs:
1.9 mickey 364: * Outputs code to the file.
1.1 deraadt 365: * Assumptions:
366: * Chars are 8 bits long.
367: * Algorithm:
1.9 mickey 368: * Maintain a BITS character long buffer (so that 8 codes will
1.1 deraadt 369: * fit in it exactly). Use the VAX insv instruction to insert each
370: * code in turn. When the buffer fills up empty it and start over.
371: */
372:
1.6 mickey 373: static const u_char lmask[9] =
1.1 deraadt 374: {0xff, 0xfe, 0xfc, 0xf8, 0xf0, 0xe0, 0xc0, 0x80, 0x00};
1.6 mickey 375: static const u_char rmask[9] =
1.1 deraadt 376: {0x00, 0x01, 0x03, 0x07, 0x0f, 0x1f, 0x3f, 0x7f, 0xff};
377:
378: static int
1.11 deraadt 379: output(struct s_zstate *zs, code_int ocode)
1.1 deraadt 380: {
1.7 mpech 381: int bits;
1.1 deraadt 382:
383: if (ocode >= 0) {
1.7 mpech 384: int r_off;
385: u_char *bp;
1.6 mickey 386:
1.1 deraadt 387: /* Get to the first byte. */
1.6 mickey 388: bp = zs->zs_bp + (zs->zs_offset >> 3);
389: r_off = zs->zs_offset & 7;
390: bits = zs->zs_n_bits;
391:
1.1 deraadt 392: /*
393: * Since ocode is always >= 8 bits, only need to mask the first
394: * hunk on the left.
395: */
1.4 millert 396: *bp = (*bp & rmask[r_off]) | ((ocode << r_off) & lmask[r_off]);
1.1 deraadt 397: bp++;
398: bits -= (8 - r_off);
399: ocode >>= 8 - r_off;
1.5 mickey 400: /* Get any 8 bit parts in the middle (<=1 for up to 16 bits) */
1.1 deraadt 401: if (bits >= 8) {
402: *bp++ = ocode;
403: ocode >>= 8;
404: bits -= 8;
405: }
406: /* Last bits. */
407: if (bits)
408: *bp = ocode;
1.5 mickey 409: zs->zs_offset += zs->zs_n_bits;
410: if (zs->zs_offset == (zs->zs_n_bits << 3)) {
1.6 mickey 411: zs->zs_bp += zs->zs_n_bits;
1.5 mickey 412: zs->zs_offset = 0;
1.1 deraadt 413: }
414: /*
415: * If the next entry is going to be too big for the ocode size,
416: * then increase it, if possible.
417: */
1.5 mickey 418: if (zs->zs_free_ent > zs->zs_maxcode ||
419: (zs->zs_clear_flg > 0)) {
1.11 deraadt 420: /*
421: * Write the whole buffer, because the input side won't
422: * discover the size increase until after it has read it
423: */
1.5 mickey 424: if (zs->zs_offset > 0) {
1.6 mickey 425: zs->zs_bp += zs->zs_n_bits;
426: zs->zs_offset = 0;
1.1 deraadt 427: }
428:
1.5 mickey 429: if (zs->zs_clear_flg) {
430: zs->zs_maxcode =
431: MAXCODE(zs->zs_n_bits = INIT_BITS);
432: zs->zs_clear_flg = 0;
1.1 deraadt 433: } else {
1.5 mickey 434: zs->zs_n_bits++;
435: if (zs->zs_n_bits == zs->zs_maxbits)
436: zs->zs_maxcode = zs->zs_maxmaxcode;
1.1 deraadt 437: else
1.5 mickey 438: zs->zs_maxcode =
1.15 deraadt 439: MAXCODE(zs->zs_n_bits);
1.1 deraadt 440: }
441: }
1.6 mickey 442:
443: if (zs->zs_bp + zs->zs_n_bits > &zs->zs_buf[ZBUFSIZ]) {
444: bits = zs->zs_bp - zs->zs_buf;
445: if (write(zs->zs_fd, zs->zs_buf, bits) != bits)
446: return (-1);
447: zs->zs_bytes_out += bits;
448: if (zs->zs_offset > 0)
449: fprintf (stderr, "zs_offset != 0\n");
450: zs->zs_bp = zs->zs_buf;
451: }
1.1 deraadt 452: } else {
453: /* At EOF, write the rest of the buffer. */
1.6 mickey 454: if (zs->zs_offset > 0)
455: zs->zs_bp += (zs->zs_offset + 7) / 8;
456: if (zs->zs_bp > zs->zs_buf) {
457: bits = zs->zs_bp - zs->zs_buf;
458: if (write(zs->zs_fd, zs->zs_buf, bits) != bits)
1.1 deraadt 459: return (-1);
1.6 mickey 460: zs->zs_bytes_out += bits;
1.1 deraadt 461: }
1.5 mickey 462: zs->zs_offset = 0;
1.6 mickey 463: zs->zs_bp = zs->zs_buf;
1.1 deraadt 464: }
465: return (0);
466: }
467:
468: /*
469: * Decompress read. This routine adapts to the codes in the file building
470: * the "string" table on-the-fly; requiring no table to be stored in the
471: * compressed file. The tables used herein are shared with those of the
472: * compress() routine. See the definitions above.
473: */
1.5 mickey 474: int
1.11 deraadt 475: zread(void *cookie, char *rbp, int num)
1.1 deraadt 476: {
1.7 mpech 477: u_int count;
1.1 deraadt 478: struct s_zstate *zs;
479: u_char *bp, header[3];
480:
481: if (num == 0)
482: return (0);
483:
484: zs = cookie;
485: count = num;
486: bp = (u_char *)rbp;
1.5 mickey 487: switch (zs->zs_state) {
1.1 deraadt 488: case S_START:
1.5 mickey 489: zs->zs_state = S_MIDDLE;
1.6 mickey 490: zs->zs_bp = zs->zs_buf;
1.12 millert 491: header[0] = header[1] = header[2] = '\0';
492: read(zs->zs_fd, header, sizeof(header));
493: break;
494: case S_MAGIC:
495: zs->zs_state = S_MIDDLE;
496: zs->zs_bp = zs->zs_buf;
497: header[0] = z_magic[0];
498: header[1] = z_magic[1];
499: header[2] = '\0';
500: read(zs->zs_fd, &header[2], 1);
1.1 deraadt 501: break;
502: case S_MIDDLE:
503: goto middle;
504: case S_EOF:
505: goto eof;
506: }
507:
508: /* Check the magic number */
1.12 millert 509: if (header[0] != z_magic[0] || header[1] != z_magic[1]) {
1.1 deraadt 510: errno = EFTYPE;
511: return (-1);
512: }
1.5 mickey 513: zs->zs_maxbits = header[2]; /* Set -b from file. */
1.13 millert 514: zs->zs_in_count += sizeof(header);
1.5 mickey 515: zs->zs_block_compress = zs->zs_maxbits & BLOCK_MASK;
516: zs->zs_maxbits &= BIT_MASK;
517: zs->zs_maxmaxcode = 1L << zs->zs_maxbits;
518: if (zs->zs_maxbits > BITS) {
1.1 deraadt 519: errno = EFTYPE;
520: return (-1);
521: }
522: /* As above, initialize the first 256 entries in the table. */
1.5 mickey 523: zs->zs_maxcode = MAXCODE(zs->zs_n_bits = INIT_BITS);
524: for (zs->zs_code = 255; zs->zs_code >= 0; zs->zs_code--) {
525: tab_prefixof(zs->zs_code) = 0;
526: tab_suffixof(zs->zs_code) = (u_char) zs->zs_code;
1.1 deraadt 527: }
1.5 mickey 528: zs->zs_free_ent = zs->zs_block_compress ? FIRST : 256;
1.1 deraadt 529:
1.5 mickey 530: zs->zs_finchar = zs->zs_oldcode = getcode(zs);
531: if (zs->zs_oldcode == -1) /* EOF already? */
1.1 deraadt 532: return (0); /* Get out of here */
533:
534: /* First code must be 8 bits = char. */
1.5 mickey 535: *bp++ = (u_char)zs->zs_finchar;
1.1 deraadt 536: count--;
1.5 mickey 537: zs->zs_stackp = de_stack;
1.1 deraadt 538:
1.5 mickey 539: while ((zs->zs_code = getcode(zs)) > -1) {
1.1 deraadt 540:
1.5 mickey 541: if ((zs->zs_code == CLEAR) && zs->zs_block_compress) {
542: for (zs->zs_code = 255; zs->zs_code >= 0;
1.11 deraadt 543: zs->zs_code--)
1.5 mickey 544: tab_prefixof(zs->zs_code) = 0;
545: zs->zs_clear_flg = 1;
546: zs->zs_free_ent = FIRST - 1;
547: if ((zs->zs_code = getcode(zs)) == -1) /* O, untimely death! */
1.1 deraadt 548: break;
549: }
1.5 mickey 550: zs->zs_incode = zs->zs_code;
1.1 deraadt 551:
552: /* Special case for KwKwK string. */
1.5 mickey 553: if (zs->zs_code >= zs->zs_free_ent) {
554: *zs->zs_stackp++ = zs->zs_finchar;
555: zs->zs_code = zs->zs_oldcode;
1.1 deraadt 556: }
557:
558: /* Generate output characters in reverse order. */
1.5 mickey 559: while (zs->zs_code >= 256) {
1.17 ! millert 560: /*
! 561: * Bad input file may cause zs_stackp to overflow
! 562: * zs_htab; check here and abort decompression,
! 563: * that's better than dumping core.
! 564: */
! 565: if (zs->zs_stackp >= (u_char *)&zs->zs_htab[HSIZE]) {
! 566: errno = EINVAL;
! 567: return (-1);
! 568: }
1.5 mickey 569: *zs->zs_stackp++ = tab_suffixof(zs->zs_code);
570: zs->zs_code = tab_prefixof(zs->zs_code);
1.1 deraadt 571: }
1.5 mickey 572: *zs->zs_stackp++ = zs->zs_finchar = tab_suffixof(zs->zs_code);
1.1 deraadt 573:
574: /* And put them out in forward order. */
575: middle: do {
1.13 millert 576: if (count-- == 0) {
577: zs->zs_bytes_out += num;
1.1 deraadt 578: return (num);
1.13 millert 579: }
1.5 mickey 580: *bp++ = *--zs->zs_stackp;
581: } while (zs->zs_stackp > de_stack);
1.1 deraadt 582:
583: /* Generate the new entry. */
1.5 mickey 584: if ((zs->zs_code = zs->zs_free_ent) < zs->zs_maxmaxcode) {
585: tab_prefixof(zs->zs_code) = (u_short) zs->zs_oldcode;
586: tab_suffixof(zs->zs_code) = zs->zs_finchar;
587: zs->zs_free_ent = zs->zs_code + 1;
1.1 deraadt 588: }
589:
590: /* Remember previous code. */
1.5 mickey 591: zs->zs_oldcode = zs->zs_incode;
1.1 deraadt 592: }
1.5 mickey 593: zs->zs_state = S_EOF;
1.13 millert 594: zs->zs_bytes_out += num - count;
1.1 deraadt 595: eof: return (num - count);
596: }
597:
598: /*-
599: * Read one code from the standard input. If EOF, return -1.
600: * Inputs:
1.9 mickey 601: * stdin
1.1 deraadt 602: * Outputs:
1.9 mickey 603: * code or -1 is returned.
1.1 deraadt 604: */
605: static code_int
1.11 deraadt 606: getcode(struct s_zstate *zs)
1.1 deraadt 607: {
1.7 mpech 608: code_int gcode;
609: int r_off, bits;
610: u_char *bp;
1.1 deraadt 611:
1.6 mickey 612: if (zs->zs_clear_flg > 0 || zs->zs_offset >= zs->zs_size ||
1.5 mickey 613: zs->zs_free_ent > zs->zs_maxcode) {
1.6 mickey 614:
615: zs->zs_bp += zs->zs_n_bits;
1.1 deraadt 616: /*
617: * If the next entry will be too big for the current gcode
618: * size, then we must increase the size. This implies reading
619: * a new buffer full, too.
620: */
1.5 mickey 621: if (zs->zs_free_ent > zs->zs_maxcode) {
622: zs->zs_n_bits++;
1.11 deraadt 623: if (zs->zs_n_bits == zs->zs_maxbits) {
624: /* Won't get any bigger now. */
1.5 mickey 625: zs->zs_maxcode = zs->zs_maxmaxcode;
1.11 deraadt 626: } else
1.5 mickey 627: zs->zs_maxcode = MAXCODE(zs->zs_n_bits);
1.1 deraadt 628: }
1.5 mickey 629: if (zs->zs_clear_flg > 0) {
630: zs->zs_maxcode = MAXCODE(zs->zs_n_bits = INIT_BITS);
631: zs->zs_clear_flg = 0;
1.1 deraadt 632: }
1.6 mickey 633:
634: /* fill the buffer up to the neck */
635: if (zs->zs_bp + zs->zs_n_bits > zs->zs_ebp) {
636: for (bp = zs->zs_buf; zs->zs_bp < zs->zs_ebp;
637: *bp++ = *zs->zs_bp++);
638: if ((bits = read(zs->zs_fd, bp, ZBUFSIZ -
1.15 deraadt 639: (bp - zs->zs_buf))) < 0)
1.6 mickey 640: return -1;
1.13 millert 641: zs->zs_in_count += bits;
1.6 mickey 642: zs->zs_bp = zs->zs_buf;
643: zs->zs_ebp = bp + bits;
644: }
645: zs->zs_offset = 0;
646: zs->zs_size = MIN(zs->zs_n_bits, zs->zs_ebp - zs->zs_bp);
647: if (zs->zs_size == 0)
648: return -1;
1.1 deraadt 649: /* Round size down to integral number of codes. */
1.5 mickey 650: zs->zs_size = (zs->zs_size << 3) - (zs->zs_n_bits - 1);
1.1 deraadt 651: }
1.6 mickey 652:
653: bp = zs->zs_bp;
654: r_off = zs->zs_offset;
1.5 mickey 655: bits = zs->zs_n_bits;
1.1 deraadt 656:
657: /* Get to the first byte. */
658: bp += (r_off >> 3);
659: r_off &= 7;
660:
661: /* Get first part (low order bits). */
662: gcode = (*bp++ >> r_off);
663: bits -= (8 - r_off);
664: r_off = 8 - r_off; /* Now, roffset into gcode word. */
665:
666: /* Get any 8 bit parts in the middle (<=1 for up to 16 bits). */
667: if (bits >= 8) {
668: gcode |= *bp++ << r_off;
669: r_off += 8;
670: bits -= 8;
671: }
672:
673: /* High order bits. */
674: gcode |= (*bp & rmask[bits]) << r_off;
1.6 mickey 675: zs->zs_offset += zs->zs_n_bits;
1.1 deraadt 676:
677: return (gcode);
678: }
679:
1.11 deraadt 680: /* Table clear for block compress. */
1.1 deraadt 681: static int
1.11 deraadt 682: cl_block(struct s_zstate *zs)
1.1 deraadt 683: {
1.7 mpech 684: long rat;
1.1 deraadt 685:
1.5 mickey 686: zs->zs_checkpoint = zs->zs_in_count + CHECK_GAP;
1.1 deraadt 687:
1.5 mickey 688: if (zs->zs_in_count > 0x007fffff) { /* Shift will overflow. */
689: rat = zs->zs_bytes_out >> 8;
1.1 deraadt 690: if (rat == 0) /* Don't divide by zero. */
691: rat = 0x7fffffff;
692: else
1.5 mickey 693: rat = zs->zs_in_count / rat;
1.11 deraadt 694: } else {
695: /* 8 fractional bits. */
696: rat = (zs->zs_in_count << 8) / zs->zs_bytes_out;
697: }
1.5 mickey 698: if (rat > zs->zs_ratio)
699: zs->zs_ratio = rat;
1.1 deraadt 700: else {
1.5 mickey 701: zs->zs_ratio = 0;
702: cl_hash(zs, (count_int) zs->zs_hsize);
703: zs->zs_free_ent = FIRST;
704: zs->zs_clear_flg = 1;
1.1 deraadt 705: if (output(zs, (code_int) CLEAR) == -1)
706: return (-1);
707: }
708: return (0);
709: }
710:
1.11 deraadt 711: /* Reset code table. */
1.1 deraadt 712: static void
1.11 deraadt 713: cl_hash(struct s_zstate *zs, count_int cl_hsize)
1.1 deraadt 714: {
1.7 mpech 715: count_int *htab_p;
716: long i, m1;
1.1 deraadt 717:
718: m1 = -1;
1.5 mickey 719: htab_p = zs->zs_htab + cl_hsize;
1.1 deraadt 720: i = cl_hsize - 16;
721: do { /* Might use Sys V memset(3) here. */
722: *(htab_p - 16) = m1;
723: *(htab_p - 15) = m1;
724: *(htab_p - 14) = m1;
725: *(htab_p - 13) = m1;
726: *(htab_p - 12) = m1;
727: *(htab_p - 11) = m1;
728: *(htab_p - 10) = m1;
729: *(htab_p - 9) = m1;
730: *(htab_p - 8) = m1;
731: *(htab_p - 7) = m1;
732: *(htab_p - 6) = m1;
733: *(htab_p - 5) = m1;
734: *(htab_p - 4) = m1;
735: *(htab_p - 3) = m1;
736: *(htab_p - 2) = m1;
737: *(htab_p - 1) = m1;
738: htab_p -= 16;
739: } while ((i -= 16) >= 0);
740: for (i += 16; i > 0; i--)
741: *--htab_p = m1;
1.3 tholo 742: }
743:
744: FILE *
1.11 deraadt 745: zopen(const char *name, const char *mode, int bits)
1.5 mickey 746: {
747: int fd;
748: void *cookie;
749: if ((fd = open(name, (*mode=='r'? O_RDONLY:O_WRONLY|O_CREAT),
1.11 deraadt 750: S_IRUSR|S_IWUSR|S_IRGRP|S_IROTH)) == -1)
1.5 mickey 751: return NULL;
1.13 millert 752: if ((cookie = z_open(fd, mode, NULL, bits, 0, 0)) == NULL) {
1.5 mickey 753: close(fd);
754: return NULL;
755: }
756: return funopen(cookie, (*mode == 'r'?zread:NULL),
1.11 deraadt 757: (*mode == 'w'?zwrite:NULL), NULL, zclose);
1.5 mickey 758: }
759:
760: void *
1.13 millert 761: z_open(int fd, const char *mode, char *name, int bits,
762: u_int32_t mtime, int gotmagic)
1.3 tholo 763: {
1.7 mpech 764: struct s_zstate *zs;
1.3 tholo 765:
1.4 millert 766: if ((mode[0] != 'r' && mode[0] != 'w') || mode[1] != '\0' ||
1.3 tholo 767: bits < 0 || bits > BITS) {
768: errno = EINVAL;
769: return (NULL);
770: }
771:
772: if ((zs = calloc(1, sizeof(struct s_zstate))) == NULL)
773: return (NULL);
774:
1.5 mickey 775: /* User settable max # bits/code. */
776: zs->zs_maxbits = bits ? bits : BITS;
777: /* Should NEVER generate this code. */
778: zs->zs_maxmaxcode = 1 << zs->zs_maxbits;
779: zs->zs_hsize = HSIZE; /* For dynamic table sizing. */
780: zs->zs_free_ent = 0; /* First unused entry. */
781: zs->zs_block_compress = BLOCK_MASK;
782: zs->zs_clear_flg = 0;
783: zs->zs_ratio = 0;
784: zs->zs_checkpoint = CHECK_GAP;
1.13 millert 785: zs->zs_in_count = 0; /* Length of input. */
1.5 mickey 786: zs->zs_out_count = 0; /* # of codes output (for debugging).*/
1.12 millert 787: zs->zs_state = gotmagic ? S_MAGIC : S_START;
1.6 mickey 788: zs->zs_offset = 0;
1.5 mickey 789: zs->zs_size = 0;
790: zs->zs_mode = mode[0];
1.6 mickey 791: zs->zs_bp = zs->zs_ebp = zs->zs_buf;
1.3 tholo 792:
1.5 mickey 793: zs->zs_fd = fd;
794: return zs;
1.1 deraadt 795: }
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