Annotation of src/usr.bin/compress/zopen.c, Revision 1.13
1.13 ! millert 1: /* $OpenBSD: zopen.c,v 1.12 2003/07/11 02:31:18 millert 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[] =
1.13 ! millert 43: "$OpenBSD: zopen.c,v 1.12 2003/07/11 02:31:18 millert 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. */
113: count_int zs_htab [HSIZE];
114: u_short zs_codetab [HSIZE];
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;
137: } w; /* Write paramenters */
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
1.13 ! millert 316: z_close(void *cookie, struct z_info *info)
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:
1.5 mickey 344: rval = close(zs->zs_fd);
1.1 deraadt 345: free(zs);
346: return (rval);
347: }
348:
1.13 ! millert 349: int
! 350: zclose(void *cookie)
! 351: {
! 352: return z_close(cookie, NULL);
! 353: }
! 354:
1.1 deraadt 355: /*-
356: * Output the given code.
357: * Inputs:
1.9 mickey 358: * code: A n_bits-bit integer. If == -1, then EOF. This assumes
1.1 deraadt 359: * that n_bits =< (long)wordsize - 1.
360: * Outputs:
1.9 mickey 361: * Outputs code to the file.
1.1 deraadt 362: * Assumptions:
363: * Chars are 8 bits long.
364: * Algorithm:
1.9 mickey 365: * Maintain a BITS character long buffer (so that 8 codes will
1.1 deraadt 366: * fit in it exactly). Use the VAX insv instruction to insert each
367: * code in turn. When the buffer fills up empty it and start over.
368: */
369:
1.6 mickey 370: static const u_char lmask[9] =
1.1 deraadt 371: {0xff, 0xfe, 0xfc, 0xf8, 0xf0, 0xe0, 0xc0, 0x80, 0x00};
1.6 mickey 372: static const u_char rmask[9] =
1.1 deraadt 373: {0x00, 0x01, 0x03, 0x07, 0x0f, 0x1f, 0x3f, 0x7f, 0xff};
374:
375: static int
1.11 deraadt 376: output(struct s_zstate *zs, code_int ocode)
1.1 deraadt 377: {
1.7 mpech 378: int bits;
1.1 deraadt 379:
380: if (ocode >= 0) {
1.7 mpech 381: int r_off;
382: u_char *bp;
1.6 mickey 383:
1.1 deraadt 384: /* Get to the first byte. */
1.6 mickey 385: bp = zs->zs_bp + (zs->zs_offset >> 3);
386: r_off = zs->zs_offset & 7;
387: bits = zs->zs_n_bits;
388:
1.1 deraadt 389: /*
390: * Since ocode is always >= 8 bits, only need to mask the first
391: * hunk on the left.
392: */
1.4 millert 393: *bp = (*bp & rmask[r_off]) | ((ocode << r_off) & lmask[r_off]);
1.1 deraadt 394: bp++;
395: bits -= (8 - r_off);
396: ocode >>= 8 - r_off;
1.5 mickey 397: /* Get any 8 bit parts in the middle (<=1 for up to 16 bits) */
1.1 deraadt 398: if (bits >= 8) {
399: *bp++ = ocode;
400: ocode >>= 8;
401: bits -= 8;
402: }
403: /* Last bits. */
404: if (bits)
405: *bp = ocode;
1.5 mickey 406: zs->zs_offset += zs->zs_n_bits;
407: if (zs->zs_offset == (zs->zs_n_bits << 3)) {
1.6 mickey 408: zs->zs_bp += zs->zs_n_bits;
1.5 mickey 409: zs->zs_offset = 0;
1.1 deraadt 410: }
411: /*
412: * If the next entry is going to be too big for the ocode size,
413: * then increase it, if possible.
414: */
1.5 mickey 415: if (zs->zs_free_ent > zs->zs_maxcode ||
416: (zs->zs_clear_flg > 0)) {
1.11 deraadt 417: /*
418: * Write the whole buffer, because the input side won't
419: * discover the size increase until after it has read it
420: */
1.5 mickey 421: if (zs->zs_offset > 0) {
1.6 mickey 422: zs->zs_bp += zs->zs_n_bits;
423: zs->zs_offset = 0;
1.1 deraadt 424: }
425:
1.5 mickey 426: if (zs->zs_clear_flg) {
427: zs->zs_maxcode =
428: MAXCODE(zs->zs_n_bits = INIT_BITS);
429: zs->zs_clear_flg = 0;
1.1 deraadt 430: } else {
1.5 mickey 431: zs->zs_n_bits++;
432: if (zs->zs_n_bits == zs->zs_maxbits)
433: zs->zs_maxcode = zs->zs_maxmaxcode;
1.1 deraadt 434: else
1.5 mickey 435: zs->zs_maxcode =
436: MAXCODE(zs->zs_n_bits);
1.1 deraadt 437: }
438: }
1.6 mickey 439:
440: if (zs->zs_bp + zs->zs_n_bits > &zs->zs_buf[ZBUFSIZ]) {
441: bits = zs->zs_bp - zs->zs_buf;
442: if (write(zs->zs_fd, zs->zs_buf, bits) != bits)
443: return (-1);
444: zs->zs_bytes_out += bits;
445: if (zs->zs_offset > 0)
446: fprintf (stderr, "zs_offset != 0\n");
447: zs->zs_bp = zs->zs_buf;
448: }
1.1 deraadt 449: } else {
450: /* At EOF, write the rest of the buffer. */
1.6 mickey 451: if (zs->zs_offset > 0)
452: zs->zs_bp += (zs->zs_offset + 7) / 8;
453: if (zs->zs_bp > zs->zs_buf) {
454: bits = zs->zs_bp - zs->zs_buf;
455: if (write(zs->zs_fd, zs->zs_buf, bits) != bits)
1.1 deraadt 456: return (-1);
1.6 mickey 457: zs->zs_bytes_out += bits;
1.1 deraadt 458: }
1.5 mickey 459: zs->zs_offset = 0;
1.6 mickey 460: zs->zs_bp = zs->zs_buf;
1.1 deraadt 461: }
462: return (0);
463: }
464:
465: /*
466: * Decompress read. This routine adapts to the codes in the file building
467: * the "string" table on-the-fly; requiring no table to be stored in the
468: * compressed file. The tables used herein are shared with those of the
469: * compress() routine. See the definitions above.
470: */
1.5 mickey 471: int
1.11 deraadt 472: zread(void *cookie, char *rbp, int num)
1.1 deraadt 473: {
1.7 mpech 474: u_int count;
1.1 deraadt 475: struct s_zstate *zs;
476: u_char *bp, header[3];
477:
478: if (num == 0)
479: return (0);
480:
481: zs = cookie;
482: count = num;
483: bp = (u_char *)rbp;
1.5 mickey 484: switch (zs->zs_state) {
1.1 deraadt 485: case S_START:
1.5 mickey 486: zs->zs_state = S_MIDDLE;
1.6 mickey 487: zs->zs_bp = zs->zs_buf;
1.12 millert 488: header[0] = header[1] = header[2] = '\0';
489: read(zs->zs_fd, header, sizeof(header));
490: break;
491: case S_MAGIC:
492: zs->zs_state = S_MIDDLE;
493: zs->zs_bp = zs->zs_buf;
494: header[0] = z_magic[0];
495: header[1] = z_magic[1];
496: header[2] = '\0';
497: read(zs->zs_fd, &header[2], 1);
1.1 deraadt 498: break;
499: case S_MIDDLE:
500: goto middle;
501: case S_EOF:
502: goto eof;
503: }
504:
505: /* Check the magic number */
1.12 millert 506: if (header[0] != z_magic[0] || header[1] != z_magic[1]) {
1.1 deraadt 507: errno = EFTYPE;
508: return (-1);
509: }
1.5 mickey 510: zs->zs_maxbits = header[2]; /* Set -b from file. */
1.13 ! millert 511: zs->zs_in_count += sizeof(header);
1.5 mickey 512: zs->zs_block_compress = zs->zs_maxbits & BLOCK_MASK;
513: zs->zs_maxbits &= BIT_MASK;
514: zs->zs_maxmaxcode = 1L << zs->zs_maxbits;
515: if (zs->zs_maxbits > BITS) {
1.1 deraadt 516: errno = EFTYPE;
517: return (-1);
518: }
519: /* As above, initialize the first 256 entries in the table. */
1.5 mickey 520: zs->zs_maxcode = MAXCODE(zs->zs_n_bits = INIT_BITS);
521: for (zs->zs_code = 255; zs->zs_code >= 0; zs->zs_code--) {
522: tab_prefixof(zs->zs_code) = 0;
523: tab_suffixof(zs->zs_code) = (u_char) zs->zs_code;
1.1 deraadt 524: }
1.5 mickey 525: zs->zs_free_ent = zs->zs_block_compress ? FIRST : 256;
1.1 deraadt 526:
1.5 mickey 527: zs->zs_finchar = zs->zs_oldcode = getcode(zs);
528: if (zs->zs_oldcode == -1) /* EOF already? */
1.1 deraadt 529: return (0); /* Get out of here */
530:
531: /* First code must be 8 bits = char. */
1.5 mickey 532: *bp++ = (u_char)zs->zs_finchar;
1.1 deraadt 533: count--;
1.5 mickey 534: zs->zs_stackp = de_stack;
1.1 deraadt 535:
1.5 mickey 536: while ((zs->zs_code = getcode(zs)) > -1) {
1.1 deraadt 537:
1.5 mickey 538: if ((zs->zs_code == CLEAR) && zs->zs_block_compress) {
539: for (zs->zs_code = 255; zs->zs_code >= 0;
1.11 deraadt 540: zs->zs_code--)
1.5 mickey 541: tab_prefixof(zs->zs_code) = 0;
542: zs->zs_clear_flg = 1;
543: zs->zs_free_ent = FIRST - 1;
544: if ((zs->zs_code = getcode(zs)) == -1) /* O, untimely death! */
1.1 deraadt 545: break;
546: }
1.5 mickey 547: zs->zs_incode = zs->zs_code;
1.1 deraadt 548:
549: /* Special case for KwKwK string. */
1.5 mickey 550: if (zs->zs_code >= zs->zs_free_ent) {
551: *zs->zs_stackp++ = zs->zs_finchar;
552: zs->zs_code = zs->zs_oldcode;
1.1 deraadt 553: }
554:
555: /* Generate output characters in reverse order. */
1.5 mickey 556: while (zs->zs_code >= 256) {
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 -
627: (bp - zs->zs_buf))) < 0)
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;
634: zs->zs_size = MIN(zs->zs_n_bits, zs->zs_ebp - zs->zs_bp);
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:
732: FILE *
1.11 deraadt 733: zopen(const char *name, const char *mode, int bits)
1.5 mickey 734: {
735: int fd;
736: void *cookie;
737: if ((fd = open(name, (*mode=='r'? O_RDONLY:O_WRONLY|O_CREAT),
1.11 deraadt 738: S_IRUSR|S_IWUSR|S_IRGRP|S_IROTH)) == -1)
1.5 mickey 739: return NULL;
1.13 ! millert 740: if ((cookie = z_open(fd, mode, NULL, bits, 0, 0)) == NULL) {
1.5 mickey 741: close(fd);
742: return NULL;
743: }
744: return funopen(cookie, (*mode == 'r'?zread:NULL),
1.11 deraadt 745: (*mode == 'w'?zwrite:NULL), NULL, zclose);
1.5 mickey 746: }
747:
748: void *
1.13 ! millert 749: z_open(int fd, const char *mode, char *name, int bits,
! 750: u_int32_t mtime, int gotmagic)
1.3 tholo 751: {
1.7 mpech 752: struct s_zstate *zs;
1.3 tholo 753:
1.4 millert 754: if ((mode[0] != 'r' && mode[0] != 'w') || mode[1] != '\0' ||
1.3 tholo 755: bits < 0 || bits > BITS) {
756: errno = EINVAL;
757: return (NULL);
758: }
759:
760: if ((zs = calloc(1, sizeof(struct s_zstate))) == NULL)
761: return (NULL);
762:
1.5 mickey 763: /* User settable max # bits/code. */
764: zs->zs_maxbits = bits ? bits : BITS;
765: /* Should NEVER generate this code. */
766: zs->zs_maxmaxcode = 1 << zs->zs_maxbits;
767: zs->zs_hsize = HSIZE; /* For dynamic table sizing. */
768: zs->zs_free_ent = 0; /* First unused entry. */
769: zs->zs_block_compress = BLOCK_MASK;
770: zs->zs_clear_flg = 0;
771: zs->zs_ratio = 0;
772: zs->zs_checkpoint = CHECK_GAP;
1.13 ! millert 773: zs->zs_in_count = 0; /* Length of input. */
1.5 mickey 774: zs->zs_out_count = 0; /* # of codes output (for debugging).*/
1.12 millert 775: zs->zs_state = gotmagic ? S_MAGIC : S_START;
1.6 mickey 776: zs->zs_offset = 0;
1.5 mickey 777: zs->zs_size = 0;
778: zs->zs_mode = mode[0];
1.6 mickey 779: zs->zs_bp = zs->zs_ebp = zs->zs_buf;
1.3 tholo 780:
1.5 mickey 781: zs->zs_fd = fd;
782: return zs;
1.1 deraadt 783: }
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