Annotation of src/usr.bin/compress/zopen.c, Revision 1.22
1.22 ! fcambus 1: /* $OpenBSD: zopen.c,v 1.21 2016/09/03 11:41:10 tedu 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: /*-
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.h>
65: #include <signal.h>
66: #include <stdio.h>
67: #include <stdlib.h>
68: #include <string.h>
69: #include <unistd.h>
1.5 mickey 70: #include <fcntl.h>
71: #include "compress.h"
1.1 deraadt 72:
1.19 deraadt 73: #define MINIMUM(a, b) (((a) < (b)) ? (a) : (b))
74:
1.1 deraadt 75: #define BITS 16 /* Default bits. */
76: #define HSIZE 69001 /* 95% occupancy */
1.6 mickey 77: #define ZBUFSIZ 8192 /* I/O buffer size */
1.1 deraadt 78:
79: /* A code_int must be able to hold 2**BITS values of type int, and also -1. */
80: typedef long code_int;
81: typedef long count_int;
82:
1.9 mickey 83: static const u_char z_magic[] =
1.1 deraadt 84: {'\037', '\235'}; /* 1F 9D */
85:
86: #define BIT_MASK 0x1f /* Defines for third byte of header. */
87: #define BLOCK_MASK 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_BITS 9 /* Initial number of bits/code. */
94:
95: #define MAXCODE(n_bits) ((1 << (n_bits)) - 1)
96:
97: struct s_zstate {
1.5 mickey 98: int zs_fd; /* File stream for I/O */
1.1 deraadt 99: char zs_mode; /* r or w */
100: enum {
1.12 millert 101: S_START, S_MAGIC, S_MIDDLE, S_EOF
1.1 deraadt 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. */
1.17 millert 107: count_int zs_htab[HSIZE];
108: u_short zs_codetab[HSIZE];
1.1 deraadt 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. */
1.13 millert 120: long zs_bytes_out; /* Length of output. */
1.5 mickey 121: long zs_out_count; /* # of codes output (for debugging).*/
1.6 mickey 122: u_char zs_buf[ZBUFSIZ]; /* 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 */
1.1 deraadt 125: union {
126: struct {
127: long zs_fcode;
128: code_int zs_ent;
129: code_int zs_hsize_reg;
130: int zs_hshift;
1.17 millert 131: } w; /* Write parameters */
1.1 deraadt 132: struct {
1.6 mickey 133: u_char *zs_stackp, *zs_ebp;
1.1 deraadt 134: int zs_finchar;
135: code_int zs_code, zs_oldcode, zs_incode;
1.6 mickey 136: int zs_size;
1.1 deraadt 137: } r; /* Read parameters */
138: } u;
139: };
140:
141: /* Definitions to retain old variable names */
1.5 mickey 142: #define zs_fcode u.w.zs_fcode
143: #define zs_ent u.w.zs_ent
144: #define zs_hsize_reg u.w.zs_hsize_reg
145: #define zs_hshift u.w.zs_hshift
146: #define zs_stackp u.r.zs_stackp
147: #define zs_finchar u.r.zs_finchar
148: #define zs_code u.r.zs_code
149: #define zs_oldcode u.r.zs_oldcode
150: #define zs_incode u.r.zs_incode
151: #define zs_size u.r.zs_size
1.6 mickey 152: #define zs_ebp u.r.zs_ebp
1.1 deraadt 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:
1.5 mickey 163: #define htabof(i) zs->zs_htab[i]
164: #define codetabof(i) zs->zs_codetab[i]
1.1 deraadt 165:
166: #define tab_prefixof(i) codetabof(i)
1.5 mickey 167: #define tab_suffixof(i) ((u_char *)(zs->zs_htab))[i]
168: #define de_stack ((u_char *)&tab_suffixof(1 << BITS))
1.1 deraadt 169:
170: #define CHECK_GAP 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 FIRST 257 /* First free entry. */
177: #define CLEAR 256 /* Table clear output code. */
178:
1.8 millert 179: static int cl_block(struct s_zstate *);
1.9 mickey 180: static void cl_hash(struct s_zstate *, count_int);
1.8 millert 181: static code_int getcode(struct s_zstate *);
182: static int output(struct s_zstate *, code_int);
1.1 deraadt 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:
1.9 mickey 189: * Modified Lempel-Ziv method (LZW). Basically finds common
1.1 deraadt 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: */
1.5 mickey 210: int
1.11 deraadt 211: zwrite(void *cookie, const char *wbp, int num)
1.1 deraadt 212: {
1.7 mpech 213: code_int i;
214: int c, disp;
1.1 deraadt 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;
1.6 mickey 223: switch (zs->zs_state) {
1.12 millert 224: case S_MAGIC:
225: return -1;
1.6 mickey 226: case S_EOF:
227: return 0;
228: case S_START:
229: zs->zs_state = S_MIDDLE;
1.1 deraadt 230:
1.6 mickey 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);
1.1 deraadt 238:
1.6 mickey 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_GAP;
247: zs->zs_maxcode = MAXCODE(zs->zs_n_bits = INIT_BITS);
248: zs->zs_free_ent = ((zs->zs_block_compress) ? FIRST : 256);
249:
250: zs->zs_ent = *bp++;
251: --count;
252:
253: zs->zs_hshift = 0;
254: for (zs->zs_fcode = (long)zs->zs_hsize; zs->zs_fcode < 65536L;
1.11 deraadt 255: zs->zs_fcode *= 2L)
1.6 mickey 256: zs->zs_hshift++;
257: /* Set hash code range bound. */
258: zs->zs_hshift = 8 - zs->zs_hshift;
259:
260: zs->zs_hsize_reg = zs->zs_hsize;
261: /* Clear hash table. */
262: cl_hash(zs, (count_int)zs->zs_hsize_reg);
1.1 deraadt 263:
1.6 mickey 264: case S_MIDDLE:
265: for (i = 0; count-- > 0;) {
266: c = *bp++;
267: zs->zs_in_count++;
268: zs->zs_fcode = (long)(((long)c << zs->zs_maxbits) +
1.11 deraadt 269: zs->zs_ent);
1.6 mickey 270: /* Xor hashing. */
271: i = ((c << zs->zs_hshift) ^ zs->zs_ent);
1.9 mickey 272:
1.6 mickey 273: if (htabof(i) == zs->zs_fcode) {
274: zs->zs_ent = codetabof(i);
275: continue;
276: } else if ((long)htabof(i) < 0) /* Empty slot. */
277: goto nomatch;
278: /* Secondary hash (after G. Knott). */
279: disp = zs->zs_hsize_reg - i;
280: if (i == 0)
1.20 tobias 281: disp = 1;
1.6 mickey 282: probe: if ((i -= disp) < 0)
283: i += zs->zs_hsize_reg;
1.1 deraadt 284:
1.6 mickey 285: if (htabof(i) == zs->zs_fcode) {
286: zs->zs_ent = codetabof(i);
287: continue;
288: }
289: if ((long)htabof(i) >= 0)
290: goto probe;
291: nomatch: if (output(zs, (code_int) zs->zs_ent) == -1)
1.1 deraadt 292: return (-1);
1.6 mickey 293: zs->zs_out_count++;
294: zs->zs_ent = c;
295: if (zs->zs_free_ent < zs->zs_maxmaxcode) {
296: /* code -> hashtable */
297: codetabof(i) = zs->zs_free_ent++;
298: htabof(i) = zs->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: }
1.1 deraadt 304: }
305: }
306: return (num);
307: }
308:
1.5 mickey 309: int
1.16 otto 310: z_close(void *cookie, struct z_info *info, const char *name, struct stat *sb)
1.1 deraadt 311: {
312: struct s_zstate *zs;
313: int rval;
314:
315: zs = cookie;
1.5 mickey 316: if (zs->zs_mode == 'w') { /* Put out the final code. */
317: if (output(zs, (code_int) zs->zs_ent) == -1) {
318: (void)close(zs->zs_fd);
1.1 deraadt 319: free(zs);
320: return (-1);
321: }
1.5 mickey 322: zs->zs_out_count++;
1.1 deraadt 323: if (output(zs, (code_int) - 1) == -1) {
1.5 mickey 324: (void)close(zs->zs_fd);
1.1 deraadt 325: free(zs);
326: return (-1);
327: }
328: }
1.13 millert 329:
330: if (info != NULL) {
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:
1.16 otto 338: #ifndef SAVECORE
339: setfile(name, zs->zs_fd, sb);
340: #endif
1.5 mickey 341: rval = close(zs->zs_fd);
1.1 deraadt 342: free(zs);
343: return (rval);
1.13 millert 344: }
345:
1.1 deraadt 346: /*-
347: * Output the given code.
348: * Inputs:
1.9 mickey 349: * code: A n_bits-bit integer. If == -1, then EOF. This assumes
1.1 deraadt 350: * that n_bits =< (long)wordsize - 1.
351: * Outputs:
1.9 mickey 352: * Outputs code to the file.
1.1 deraadt 353: * Assumptions:
354: * Chars are 8 bits long.
355: * Algorithm:
1.9 mickey 356: * Maintain a BITS character long buffer (so that 8 codes will
1.1 deraadt 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:
1.6 mickey 361: static const u_char lmask[9] =
1.1 deraadt 362: {0xff, 0xfe, 0xfc, 0xf8, 0xf0, 0xe0, 0xc0, 0x80, 0x00};
1.6 mickey 363: static const u_char rmask[9] =
1.1 deraadt 364: {0x00, 0x01, 0x03, 0x07, 0x0f, 0x1f, 0x3f, 0x7f, 0xff};
365:
366: static int
1.11 deraadt 367: output(struct s_zstate *zs, code_int ocode)
1.1 deraadt 368: {
1.7 mpech 369: int bits;
1.1 deraadt 370:
371: if (ocode >= 0) {
1.7 mpech 372: int r_off;
373: u_char *bp;
1.6 mickey 374:
1.1 deraadt 375: /* Get to the first byte. */
1.6 mickey 376: bp = zs->zs_bp + (zs->zs_offset >> 3);
377: r_off = zs->zs_offset & 7;
378: bits = zs->zs_n_bits;
379:
1.1 deraadt 380: /*
381: * Since ocode is always >= 8 bits, only need to mask the first
382: * hunk on the left.
383: */
1.4 millert 384: *bp = (*bp & rmask[r_off]) | ((ocode << r_off) & lmask[r_off]);
1.1 deraadt 385: bp++;
386: bits -= (8 - r_off);
387: ocode >>= 8 - r_off;
1.5 mickey 388: /* Get any 8 bit parts in the middle (<=1 for up to 16 bits) */
1.1 deraadt 389: if (bits >= 8) {
390: *bp++ = ocode;
391: ocode >>= 8;
392: bits -= 8;
393: }
394: /* Last bits. */
395: if (bits)
396: *bp = ocode;
1.5 mickey 397: zs->zs_offset += zs->zs_n_bits;
398: if (zs->zs_offset == (zs->zs_n_bits << 3)) {
1.6 mickey 399: zs->zs_bp += zs->zs_n_bits;
1.5 mickey 400: zs->zs_offset = 0;
1.1 deraadt 401: }
402: /*
403: * If the next entry is going to be too big for the ocode size,
404: * then increase it, if possible.
405: */
1.5 mickey 406: if (zs->zs_free_ent > zs->zs_maxcode ||
407: (zs->zs_clear_flg > 0)) {
1.11 deraadt 408: /*
409: * Write the whole buffer, because the input side won't
410: * discover the size increase until after it has read it
411: */
1.5 mickey 412: if (zs->zs_offset > 0) {
1.6 mickey 413: zs->zs_bp += zs->zs_n_bits;
414: zs->zs_offset = 0;
1.1 deraadt 415: }
416:
1.5 mickey 417: if (zs->zs_clear_flg) {
418: zs->zs_maxcode =
419: MAXCODE(zs->zs_n_bits = INIT_BITS);
420: zs->zs_clear_flg = 0;
1.1 deraadt 421: } else {
1.5 mickey 422: zs->zs_n_bits++;
423: if (zs->zs_n_bits == zs->zs_maxbits)
424: zs->zs_maxcode = zs->zs_maxmaxcode;
1.1 deraadt 425: else
1.5 mickey 426: zs->zs_maxcode =
1.15 deraadt 427: MAXCODE(zs->zs_n_bits);
1.1 deraadt 428: }
429: }
1.6 mickey 430:
431: if (zs->zs_bp + zs->zs_n_bits > &zs->zs_buf[ZBUFSIZ]) {
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, "zs_offset != 0\n");
438: zs->zs_bp = zs->zs_buf;
439: }
1.1 deraadt 440: } else {
441: /* At EOF, write the rest of the buffer. */
1.6 mickey 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)
1.1 deraadt 447: return (-1);
1.6 mickey 448: zs->zs_bytes_out += bits;
1.1 deraadt 449: }
1.5 mickey 450: zs->zs_offset = 0;
1.6 mickey 451: zs->zs_bp = zs->zs_buf;
1.1 deraadt 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: */
1.5 mickey 462: int
1.11 deraadt 463: zread(void *cookie, char *rbp, int num)
1.1 deraadt 464: {
1.7 mpech 465: u_int count;
1.1 deraadt 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;
1.5 mickey 475: switch (zs->zs_state) {
1.1 deraadt 476: case S_START:
1.5 mickey 477: zs->zs_state = S_MIDDLE;
1.6 mickey 478: zs->zs_bp = zs->zs_buf;
1.12 millert 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);
1.1 deraadt 489: break;
490: case S_MIDDLE:
491: goto middle;
492: case S_EOF:
493: goto eof;
494: }
495:
496: /* Check the magic number */
1.12 millert 497: if (header[0] != z_magic[0] || header[1] != z_magic[1]) {
1.1 deraadt 498: errno = EFTYPE;
499: return (-1);
500: }
1.5 mickey 501: zs->zs_maxbits = header[2]; /* Set -b from file. */
1.13 millert 502: zs->zs_in_count += sizeof(header);
1.5 mickey 503: zs->zs_block_compress = zs->zs_maxbits & BLOCK_MASK;
504: zs->zs_maxbits &= BIT_MASK;
505: zs->zs_maxmaxcode = 1L << zs->zs_maxbits;
506: if (zs->zs_maxbits > BITS) {
1.1 deraadt 507: errno = EFTYPE;
508: return (-1);
509: }
510: /* As above, initialize the first 256 entries in the table. */
1.5 mickey 511: zs->zs_maxcode = MAXCODE(zs->zs_n_bits = INIT_BITS);
512: for (zs->zs_code = 255; zs->zs_code >= 0; zs->zs_code--) {
513: tab_prefixof(zs->zs_code) = 0;
514: tab_suffixof(zs->zs_code) = (u_char) zs->zs_code;
1.1 deraadt 515: }
1.5 mickey 516: zs->zs_free_ent = zs->zs_block_compress ? FIRST : 256;
1.1 deraadt 517:
1.5 mickey 518: zs->zs_finchar = zs->zs_oldcode = getcode(zs);
519: if (zs->zs_oldcode == -1) /* EOF already? */
1.1 deraadt 520: return (0); /* Get out of here */
521:
522: /* First code must be 8 bits = char. */
1.5 mickey 523: *bp++ = (u_char)zs->zs_finchar;
1.1 deraadt 524: count--;
1.5 mickey 525: zs->zs_stackp = de_stack;
1.1 deraadt 526:
1.5 mickey 527: while ((zs->zs_code = getcode(zs)) > -1) {
1.1 deraadt 528:
1.5 mickey 529: if ((zs->zs_code == CLEAR) && zs->zs_block_compress) {
530: for (zs->zs_code = 255; zs->zs_code >= 0;
1.11 deraadt 531: zs->zs_code--)
1.5 mickey 532: tab_prefixof(zs->zs_code) = 0;
533: zs->zs_clear_flg = 1;
534: zs->zs_free_ent = FIRST - 1;
535: if ((zs->zs_code = getcode(zs)) == -1) /* O, untimely death! */
1.1 deraadt 536: break;
537: }
1.5 mickey 538: zs->zs_incode = zs->zs_code;
1.1 deraadt 539:
540: /* Special case for KwKwK string. */
1.5 mickey 541: if (zs->zs_code >= zs->zs_free_ent) {
542: *zs->zs_stackp++ = zs->zs_finchar;
543: zs->zs_code = zs->zs_oldcode;
1.1 deraadt 544: }
545:
546: /* Generate output characters in reverse order. */
1.5 mickey 547: while (zs->zs_code >= 256) {
1.17 millert 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_stackp >= (u_char *)&zs->zs_htab[HSIZE]) {
554: errno = EINVAL;
555: return (-1);
556: }
1.5 mickey 557: *zs->zs_stackp++ = tab_suffixof(zs->zs_code);
558: zs->zs_code = tab_prefixof(zs->zs_code);
1.1 deraadt 559: }
1.5 mickey 560: *zs->zs_stackp++ = zs->zs_finchar = tab_suffixof(zs->zs_code);
1.1 deraadt 561:
562: /* And put them out in forward order. */
563: middle: do {
1.13 millert 564: if (count-- == 0) {
565: zs->zs_bytes_out += num;
1.1 deraadt 566: return (num);
1.13 millert 567: }
1.5 mickey 568: *bp++ = *--zs->zs_stackp;
569: } while (zs->zs_stackp > de_stack);
1.1 deraadt 570:
571: /* Generate the new entry. */
1.5 mickey 572: if ((zs->zs_code = zs->zs_free_ent) < zs->zs_maxmaxcode) {
573: tab_prefixof(zs->zs_code) = (u_short) zs->zs_oldcode;
574: tab_suffixof(zs->zs_code) = zs->zs_finchar;
575: zs->zs_free_ent = zs->zs_code + 1;
1.1 deraadt 576: }
577:
578: /* Remember previous code. */
1.5 mickey 579: zs->zs_oldcode = zs->zs_incode;
1.1 deraadt 580: }
1.5 mickey 581: zs->zs_state = S_EOF;
1.13 millert 582: zs->zs_bytes_out += num - count;
1.1 deraadt 583: eof: return (num - count);
584: }
585:
586: /*-
587: * Read one code from the standard input. If EOF, return -1.
588: * Inputs:
1.9 mickey 589: * stdin
1.1 deraadt 590: * Outputs:
1.9 mickey 591: * code or -1 is returned.
1.1 deraadt 592: */
593: static code_int
1.11 deraadt 594: getcode(struct s_zstate *zs)
1.1 deraadt 595: {
1.7 mpech 596: code_int gcode;
597: int r_off, bits;
598: u_char *bp;
1.1 deraadt 599:
1.6 mickey 600: if (zs->zs_clear_flg > 0 || zs->zs_offset >= zs->zs_size ||
1.5 mickey 601: zs->zs_free_ent > zs->zs_maxcode) {
1.6 mickey 602:
603: zs->zs_bp += zs->zs_n_bits;
1.1 deraadt 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: */
1.5 mickey 609: if (zs->zs_free_ent > zs->zs_maxcode) {
610: zs->zs_n_bits++;
1.11 deraadt 611: if (zs->zs_n_bits == zs->zs_maxbits) {
612: /* Won't get any bigger now. */
1.5 mickey 613: zs->zs_maxcode = zs->zs_maxmaxcode;
1.11 deraadt 614: } else
1.5 mickey 615: zs->zs_maxcode = MAXCODE(zs->zs_n_bits);
1.1 deraadt 616: }
1.5 mickey 617: if (zs->zs_clear_flg > 0) {
618: zs->zs_maxcode = MAXCODE(zs->zs_n_bits = INIT_BITS);
619: zs->zs_clear_flg = 0;
1.1 deraadt 620: }
1.6 mickey 621:
622: /* fill the buffer up to the neck */
623: if (zs->zs_bp + zs->zs_n_bits > zs->zs_ebp) {
624: for (bp = zs->zs_buf; zs->zs_bp < zs->zs_ebp;
625: *bp++ = *zs->zs_bp++);
626: if ((bits = read(zs->zs_fd, bp, ZBUFSIZ -
1.15 deraadt 627: (bp - zs->zs_buf))) < 0)
1.6 mickey 628: return -1;
1.13 millert 629: zs->zs_in_count += bits;
1.6 mickey 630: zs->zs_bp = zs->zs_buf;
631: zs->zs_ebp = bp + bits;
632: }
633: zs->zs_offset = 0;
1.19 deraadt 634: zs->zs_size = MINIMUM(zs->zs_n_bits, zs->zs_ebp - zs->zs_bp);
1.6 mickey 635: if (zs->zs_size == 0)
636: return -1;
1.1 deraadt 637: /* Round size down to integral number of codes. */
1.5 mickey 638: zs->zs_size = (zs->zs_size << 3) - (zs->zs_n_bits - 1);
1.1 deraadt 639: }
1.6 mickey 640:
641: bp = zs->zs_bp;
642: r_off = zs->zs_offset;
1.5 mickey 643: bits = zs->zs_n_bits;
1.1 deraadt 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;
1.6 mickey 663: zs->zs_offset += zs->zs_n_bits;
1.1 deraadt 664:
665: return (gcode);
666: }
667:
1.11 deraadt 668: /* Table clear for block compress. */
1.1 deraadt 669: static int
1.11 deraadt 670: cl_block(struct s_zstate *zs)
1.1 deraadt 671: {
1.7 mpech 672: long rat;
1.1 deraadt 673:
1.5 mickey 674: zs->zs_checkpoint = zs->zs_in_count + CHECK_GAP;
1.1 deraadt 675:
1.5 mickey 676: if (zs->zs_in_count > 0x007fffff) { /* Shift will overflow. */
677: rat = zs->zs_bytes_out >> 8;
1.1 deraadt 678: if (rat == 0) /* Don't divide by zero. */
679: rat = 0x7fffffff;
680: else
1.5 mickey 681: rat = zs->zs_in_count / rat;
1.11 deraadt 682: } else {
683: /* 8 fractional bits. */
684: rat = (zs->zs_in_count << 8) / zs->zs_bytes_out;
685: }
1.5 mickey 686: if (rat > zs->zs_ratio)
687: zs->zs_ratio = rat;
1.1 deraadt 688: else {
1.5 mickey 689: zs->zs_ratio = 0;
690: cl_hash(zs, (count_int) zs->zs_hsize);
691: zs->zs_free_ent = FIRST;
692: zs->zs_clear_flg = 1;
1.1 deraadt 693: if (output(zs, (code_int) CLEAR) == -1)
694: return (-1);
695: }
696: return (0);
697: }
698:
1.11 deraadt 699: /* Reset code table. */
1.1 deraadt 700: static void
1.11 deraadt 701: cl_hash(struct s_zstate *zs, count_int cl_hsize)
1.1 deraadt 702: {
1.7 mpech 703: count_int *htab_p;
704: long i, m1;
1.1 deraadt 705:
706: m1 = -1;
1.5 mickey 707: htab_p = zs->zs_htab + cl_hsize;
1.1 deraadt 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;
1.3 tholo 730: }
731:
1.5 mickey 732: void *
1.21 tedu 733: z_wopen(int fd, char *name, int bits, u_int32_t mtime)
1.3 tholo 734: {
1.7 mpech 735: struct s_zstate *zs;
1.3 tholo 736:
1.21 tedu 737: if (bits < 0 || bits > BITS) {
1.3 tholo 738: errno = EINVAL;
739: return (NULL);
740: }
741:
742: if ((zs = calloc(1, sizeof(struct s_zstate))) == NULL)
743: return (NULL);
744:
1.5 mickey 745: /* User settable max # bits/code. */
746: zs->zs_maxbits = bits ? bits : BITS;
747: /* Should NEVER generate this code. */
748: zs->zs_maxmaxcode = 1 << zs->zs_maxbits;
749: zs->zs_hsize = HSIZE; /* For dynamic table sizing. */
750: zs->zs_free_ent = 0; /* First unused entry. */
751: zs->zs_block_compress = BLOCK_MASK;
752: zs->zs_clear_flg = 0;
753: zs->zs_ratio = 0;
754: zs->zs_checkpoint = CHECK_GAP;
1.13 millert 755: zs->zs_in_count = 0; /* Length of input. */
1.5 mickey 756: zs->zs_out_count = 0; /* # of codes output (for debugging).*/
1.21 tedu 757: zs->zs_state = S_START;
758: zs->zs_offset = 0;
759: zs->zs_size = 0;
760: zs->zs_mode = 'w';
761: zs->zs_bp = zs->zs_ebp = zs->zs_buf;
762:
763: zs->zs_fd = fd;
764: return zs;
765: }
766:
767: void *
768: z_ropen(int fd, char *name, int gotmagic)
769: {
770: struct s_zstate *zs;
771:
772: if ((zs = calloc(1, sizeof(struct s_zstate))) == NULL)
773: return (NULL);
774:
775: /* User settable max # bits/code. */
776: zs->zs_maxbits = 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;
785: zs->zs_in_count = 0; /* Length of input. */
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;
1.21 tedu 790: zs->zs_mode = 'r';
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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