Annotation of src/usr.bin/compress/zopen.c, Revision 1.8
1.8 ! millert 1: /* $OpenBSD: zopen.c,v 1.7 2001/11/19 19:02:13 mpech 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.
20: * 3. All advertising materials mentioning features or use of this software
21: * must display the following acknowledgement:
22: * This product includes software developed by the University of
23: * California, Berkeley and its contributors.
24: * 4. Neither the name of the University nor the names of its contributors
25: * may be used to endorse or promote products derived from this software
26: * without specific prior written permission.
27: *
28: * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
29: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
30: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
31: * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
32: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
33: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
34: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
35: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
36: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
37: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
38: * SUCH DAMAGE.
39: */
40:
41: #if defined(LIBC_SCCS) && !defined(lint)
42: #if 0
43: static char sccsid[] = "@(#)zopen.c 8.1 (Berkeley) 6/27/93";
44: #else
1.8 ! millert 45: static char rcsid[] = "$OpenBSD: zopen.c,v 1.7 2001/11/19 19:02:13 mpech Exp $";
1.1 deraadt 46: #endif
47: #endif /* LIBC_SCCS and not lint */
48:
49: /*-
50: * fcompress.c - File compression ala IEEE Computer, June 1984.
51: *
52: * Compress authors:
53: * Spencer W. Thomas (decvax!utah-cs!thomas)
54: * Jim McKie (decvax!mcvax!jim)
55: * Steve Davies (decvax!vax135!petsd!peora!srd)
56: * Ken Turkowski (decvax!decwrl!turtlevax!ken)
57: * James A. Woods (decvax!ihnp4!ames!jaw)
58: * Joe Orost (decvax!vax135!petsd!joe)
59: *
60: * Cleaned up and converted to library returning I/O streams by
61: * Diomidis Spinellis <dds@doc.ic.ac.uk>.
62: *
63: * zopen(filename, mode, bits)
64: * Returns a FILE * that can be used for read or write. The modes
65: * supported are only "r" and "w". Seeking is not allowed. On
66: * reading the file is decompressed, on writing it is compressed.
67: * The output is compatible with compress(1) with 16 bit tables.
68: * Any file produced by compress(1) can be read.
69: */
70:
71: #include <sys/param.h>
72: #include <sys/stat.h>
73:
74: #include <ctype.h>
75: #include <errno.h>
76: #include <signal.h>
77: #include <stdio.h>
78: #include <stdlib.h>
79: #include <string.h>
80: #include <unistd.h>
1.5 mickey 81: #include <fcntl.h>
82: #include "compress.h"
1.1 deraadt 83:
84: #define BITS 16 /* Default bits. */
85: #define HSIZE 69001 /* 95% occupancy */
1.6 mickey 86: #define ZBUFSIZ 8192 /* I/O buffer size */
1.1 deraadt 87:
88: /* A code_int must be able to hold 2**BITS values of type int, and also -1. */
89: typedef long code_int;
90: typedef long count_int;
91:
1.5 mickey 92: static u_char z_magic[] =
1.1 deraadt 93: {'\037', '\235'}; /* 1F 9D */
94:
95: #define BIT_MASK 0x1f /* Defines for third byte of header. */
96: #define BLOCK_MASK 0x80
97:
98: /*
99: * Masks 0x40 and 0x20 are free. I think 0x20 should mean that there is
100: * a fourth header byte (for expansion).
101: */
102: #define INIT_BITS 9 /* Initial number of bits/code. */
103:
104: #define MAXCODE(n_bits) ((1 << (n_bits)) - 1)
105:
106: struct s_zstate {
1.5 mickey 107: int zs_fd; /* File stream for I/O */
1.1 deraadt 108: char zs_mode; /* r or w */
109: enum {
110: S_START, S_MIDDLE, S_EOF
111: } zs_state; /* State of computation */
112: int zs_n_bits; /* Number of bits/code. */
113: int zs_maxbits; /* User settable max # bits/code. */
114: code_int zs_maxcode; /* Maximum code, given n_bits. */
115: code_int zs_maxmaxcode; /* Should NEVER generate this code. */
116: count_int zs_htab [HSIZE];
117: u_short zs_codetab [HSIZE];
118: code_int zs_hsize; /* For dynamic table sizing. */
119: code_int zs_free_ent; /* First unused entry. */
120: /*
121: * Block compression parameters -- after all codes are used up,
122: * and compression rate changes, start over.
123: */
124: int zs_block_compress;
125: int zs_clear_flg;
126: long zs_ratio;
127: count_int zs_checkpoint;
128: long zs_in_count; /* Length of input. */
129: long zs_bytes_out; /* Length of compressed output. */
1.5 mickey 130: long zs_out_count; /* # of codes output (for debugging).*/
1.6 mickey 131: u_char zs_buf[ZBUFSIZ]; /* I/O buffer */
132: u_char *zs_bp; /* Current I/O window in the zs_buf */
133: int zs_offset; /* Number of bits in the zs_buf */
1.1 deraadt 134: union {
135: struct {
136: long zs_fcode;
137: code_int zs_ent;
138: code_int zs_hsize_reg;
139: int zs_hshift;
140: } w; /* Write paramenters */
141: struct {
1.6 mickey 142: u_char *zs_stackp, *zs_ebp;
1.1 deraadt 143: int zs_finchar;
144: code_int zs_code, zs_oldcode, zs_incode;
1.6 mickey 145: int zs_size;
1.1 deraadt 146: } r; /* Read parameters */
147: } u;
148: };
149:
150: /* Definitions to retain old variable names */
1.5 mickey 151: #define zs_fcode u.w.zs_fcode
152: #define zs_ent u.w.zs_ent
153: #define zs_hsize_reg u.w.zs_hsize_reg
154: #define zs_hshift u.w.zs_hshift
155: #define zs_stackp u.r.zs_stackp
156: #define zs_finchar u.r.zs_finchar
157: #define zs_code u.r.zs_code
158: #define zs_oldcode u.r.zs_oldcode
159: #define zs_incode u.r.zs_incode
160: #define zs_size u.r.zs_size
1.6 mickey 161: #define zs_ebp u.r.zs_ebp
1.1 deraadt 162:
163: /*
164: * To save much memory, we overlay the table used by compress() with those
165: * used by decompress(). The tab_prefix table is the same size and type as
166: * the codetab. The tab_suffix table needs 2**BITS characters. We get this
167: * from the beginning of htab. The output stack uses the rest of htab, and
168: * contains characters. There is plenty of room for any possible stack
169: * (stack used to be 8000 characters).
170: */
171:
1.5 mickey 172: #define htabof(i) zs->zs_htab[i]
173: #define codetabof(i) zs->zs_codetab[i]
1.1 deraadt 174:
175: #define tab_prefixof(i) codetabof(i)
1.5 mickey 176: #define tab_suffixof(i) ((u_char *)(zs->zs_htab))[i]
177: #define de_stack ((u_char *)&tab_suffixof(1 << BITS))
1.1 deraadt 178:
179: #define CHECK_GAP 10000 /* Ratio check interval. */
180:
181: /*
182: * the next two codes should not be changed lightly, as they must not
183: * lie within the contiguous general code space.
184: */
185: #define FIRST 257 /* First free entry. */
186: #define CLEAR 256 /* Table clear output code. */
187:
1.8 ! millert 188: static int cl_block(struct s_zstate *);
! 189: static void cl_hash(struct s_zstate *, register count_int);
! 190: static code_int getcode(struct s_zstate *);
! 191: static int output(struct s_zstate *, code_int);
1.1 deraadt 192:
193: /*-
194: * Algorithm from "A Technique for High Performance Data Compression",
195: * Terry A. Welch, IEEE Computer Vol 17, No 6 (June 1984), pp 8-19.
196: *
197: * Algorithm:
198: * Modified Lempel-Ziv method (LZW). Basically finds common
199: * substrings and replaces them with a variable size code. This is
200: * deterministic, and can be done on the fly. Thus, the decompression
201: * procedure needs no input table, but tracks the way the table was built.
202: */
203:
204: /*-
205: * compress write
206: *
207: * Algorithm: use open addressing double hashing (no chaining) on the
208: * prefix code / next character combination. We do a variant of Knuth's
209: * algorithm D (vol. 3, sec. 6.4) along with G. Knott's relatively-prime
210: * secondary probe. Here, the modular division first probe is gives way
211: * to a faster exclusive-or manipulation. Also do block compression with
212: * an adaptive reset, whereby the code table is cleared when the compression
213: * ratio decreases, but after the table fills. The variable-length output
214: * codes are re-sized at this point, and a special CLEAR code is generated
215: * for the decompressor. Late addition: construct the table according to
216: * file size for noticeable speed improvement on small files. Please direct
217: * questions about this implementation to ames!jaw.
218: */
1.5 mickey 219: int
1.1 deraadt 220: zwrite(cookie, wbp, num)
221: void *cookie;
222: const char *wbp;
223: int num;
224: {
1.7 mpech 225: code_int i;
226: int c, disp;
1.1 deraadt 227: struct s_zstate *zs;
228: const u_char *bp;
229: u_char tmp;
230: int count;
231:
232: zs = cookie;
233: count = num;
234: bp = (u_char *)wbp;
1.6 mickey 235: switch (zs->zs_state) {
236: case S_EOF:
237: return 0;
238: case S_START:
239: zs->zs_state = S_MIDDLE;
1.1 deraadt 240:
1.6 mickey 241: zs->zs_maxmaxcode = 1L << zs->zs_maxbits;
242: if (write(zs->zs_fd, z_magic, sizeof(z_magic)) !=
243: sizeof(z_magic))
244: return (-1);
245: tmp = (u_char)(zs->zs_maxbits | zs->zs_block_compress);
246: if (write(zs->zs_fd, &tmp, sizeof(tmp)) != sizeof(tmp))
247: return (-1);
1.1 deraadt 248:
1.6 mickey 249: zs->zs_bp = zs->zs_buf;
250: zs->zs_offset = 0;
251: zs->zs_bytes_out = 3; /* Includes 3-byte header mojo. */
252: zs->zs_out_count = 0;
253: zs->zs_clear_flg = 0;
254: zs->zs_ratio = 0;
255: zs->zs_in_count = 1;
256: zs->zs_checkpoint = CHECK_GAP;
257: zs->zs_maxcode = MAXCODE(zs->zs_n_bits = INIT_BITS);
258: zs->zs_free_ent = ((zs->zs_block_compress) ? FIRST : 256);
259:
260: zs->zs_ent = *bp++;
261: --count;
262:
263: zs->zs_hshift = 0;
264: for (zs->zs_fcode = (long)zs->zs_hsize; zs->zs_fcode < 65536L;
265: zs->zs_fcode *= 2L)
266: zs->zs_hshift++;
267: /* Set hash code range bound. */
268: zs->zs_hshift = 8 - zs->zs_hshift;
269:
270: zs->zs_hsize_reg = zs->zs_hsize;
271: /* Clear hash table. */
272: cl_hash(zs, (count_int)zs->zs_hsize_reg);
1.1 deraadt 273:
1.6 mickey 274: case S_MIDDLE:
275: for (i = 0; count-- > 0;) {
276: c = *bp++;
277: zs->zs_in_count++;
278: zs->zs_fcode = (long)(((long)c << zs->zs_maxbits) +
279: zs->zs_ent);
280: /* Xor hashing. */
281: i = ((c << zs->zs_hshift) ^ zs->zs_ent);
282:
283: if (htabof(i) == zs->zs_fcode) {
284: zs->zs_ent = codetabof(i);
285: continue;
286: } else if ((long)htabof(i) < 0) /* Empty slot. */
287: goto nomatch;
288: /* Secondary hash (after G. Knott). */
289: disp = zs->zs_hsize_reg - i;
290: if (i == 0)
1.1 deraadt 291: disp = 1;
1.6 mickey 292: probe: if ((i -= disp) < 0)
293: i += zs->zs_hsize_reg;
1.1 deraadt 294:
1.6 mickey 295: if (htabof(i) == zs->zs_fcode) {
296: zs->zs_ent = codetabof(i);
297: continue;
298: }
299: if ((long)htabof(i) >= 0)
300: goto probe;
301: nomatch: if (output(zs, (code_int) zs->zs_ent) == -1)
1.1 deraadt 302: return (-1);
1.6 mickey 303: zs->zs_out_count++;
304: zs->zs_ent = c;
305: if (zs->zs_free_ent < zs->zs_maxmaxcode) {
306: /* code -> hashtable */
307: codetabof(i) = zs->zs_free_ent++;
308: htabof(i) = zs->zs_fcode;
309: } else if ((count_int)zs->zs_in_count >=
310: zs->zs_checkpoint && zs->zs_block_compress) {
311: if (cl_block(zs) == -1)
312: return (-1);
313: }
1.1 deraadt 314: }
315: }
316: return (num);
317: }
318:
1.5 mickey 319: int
1.1 deraadt 320: zclose(cookie)
321: void *cookie;
322: {
323: struct s_zstate *zs;
324: int rval;
325:
326: zs = cookie;
1.5 mickey 327: if (zs->zs_mode == 'w') { /* Put out the final code. */
328: if (output(zs, (code_int) zs->zs_ent) == -1) {
329: (void)close(zs->zs_fd);
1.1 deraadt 330: free(zs);
331: return (-1);
332: }
1.5 mickey 333: zs->zs_out_count++;
1.1 deraadt 334: if (output(zs, (code_int) - 1) == -1) {
1.5 mickey 335: (void)close(zs->zs_fd);
1.1 deraadt 336: free(zs);
337: return (-1);
338: }
339: }
1.5 mickey 340: rval = close(zs->zs_fd);
1.1 deraadt 341: free(zs);
342: return (rval);
343: }
344:
345: /*-
346: * Output the given code.
347: * Inputs:
348: * code: A n_bits-bit integer. If == -1, then EOF. This assumes
349: * that n_bits =< (long)wordsize - 1.
350: * Outputs:
351: * Outputs code to the file.
352: * Assumptions:
353: * Chars are 8 bits long.
354: * Algorithm:
355: * Maintain a BITS character long buffer (so that 8 codes will
356: * fit in it exactly). Use the VAX insv instruction to insert each
357: * code in turn. When the buffer fills up empty it and start over.
358: */
359:
1.6 mickey 360: static const u_char lmask[9] =
1.1 deraadt 361: {0xff, 0xfe, 0xfc, 0xf8, 0xf0, 0xe0, 0xc0, 0x80, 0x00};
1.6 mickey 362: static const u_char rmask[9] =
1.1 deraadt 363: {0x00, 0x01, 0x03, 0x07, 0x0f, 0x1f, 0x3f, 0x7f, 0xff};
364:
365: static int
366: output(zs, ocode)
1.7 mpech 367: struct s_zstate *zs;
1.1 deraadt 368: code_int ocode;
369: {
1.7 mpech 370: int bits;
1.1 deraadt 371:
372: if (ocode >= 0) {
1.7 mpech 373: int r_off;
374: u_char *bp;
1.6 mickey 375:
1.1 deraadt 376: /* Get to the first byte. */
1.6 mickey 377: bp = zs->zs_bp + (zs->zs_offset >> 3);
378: r_off = zs->zs_offset & 7;
379: bits = zs->zs_n_bits;
380:
1.1 deraadt 381: /*
382: * Since ocode is always >= 8 bits, only need to mask the first
383: * hunk on the left.
384: */
1.4 millert 385: *bp = (*bp & rmask[r_off]) | ((ocode << r_off) & lmask[r_off]);
1.1 deraadt 386: bp++;
387: bits -= (8 - r_off);
388: ocode >>= 8 - r_off;
1.5 mickey 389: /* Get any 8 bit parts in the middle (<=1 for up to 16 bits) */
1.1 deraadt 390: if (bits >= 8) {
391: *bp++ = ocode;
392: ocode >>= 8;
393: bits -= 8;
394: }
395: /* Last bits. */
396: if (bits)
397: *bp = ocode;
1.5 mickey 398: zs->zs_offset += zs->zs_n_bits;
399: if (zs->zs_offset == (zs->zs_n_bits << 3)) {
1.6 mickey 400: zs->zs_bp += zs->zs_n_bits;
1.5 mickey 401: zs->zs_offset = 0;
1.1 deraadt 402: }
403: /*
404: * If the next entry is going to be too big for the ocode size,
405: * then increase it, if possible.
406: */
1.5 mickey 407: if (zs->zs_free_ent > zs->zs_maxcode ||
408: (zs->zs_clear_flg > 0)) {
1.1 deraadt 409: /*
410: * Write the whole buffer, because the input side won't
1.5 mickey 411: * discover the size increase until after it has read it
1.1 deraadt 412: */
1.5 mickey 413: if (zs->zs_offset > 0) {
1.6 mickey 414: zs->zs_bp += zs->zs_n_bits;
415: zs->zs_offset = 0;
1.1 deraadt 416: }
417:
1.5 mickey 418: if (zs->zs_clear_flg) {
419: zs->zs_maxcode =
420: MAXCODE(zs->zs_n_bits = INIT_BITS);
421: zs->zs_clear_flg = 0;
1.1 deraadt 422: } else {
1.5 mickey 423: zs->zs_n_bits++;
424: if (zs->zs_n_bits == zs->zs_maxbits)
425: zs->zs_maxcode = zs->zs_maxmaxcode;
1.1 deraadt 426: else
1.5 mickey 427: zs->zs_maxcode =
428: MAXCODE(zs->zs_n_bits);
1.1 deraadt 429: }
430: }
1.6 mickey 431:
432: if (zs->zs_bp + zs->zs_n_bits > &zs->zs_buf[ZBUFSIZ]) {
433: bits = zs->zs_bp - zs->zs_buf;
434: if (write(zs->zs_fd, zs->zs_buf, bits) != bits)
435: return (-1);
436: zs->zs_bytes_out += bits;
437: if (zs->zs_offset > 0)
438: fprintf (stderr, "zs_offset != 0\n");
439: zs->zs_bp = zs->zs_buf;
440: }
1.1 deraadt 441: } else {
442: /* At EOF, write the rest of the buffer. */
1.6 mickey 443: if (zs->zs_offset > 0)
444: zs->zs_bp += (zs->zs_offset + 7) / 8;
445: if (zs->zs_bp > zs->zs_buf) {
446: bits = zs->zs_bp - zs->zs_buf;
447: if (write(zs->zs_fd, zs->zs_buf, bits) != bits)
1.1 deraadt 448: return (-1);
1.6 mickey 449: zs->zs_bytes_out += bits;
1.1 deraadt 450: }
1.5 mickey 451: zs->zs_offset = 0;
1.6 mickey 452: zs->zs_bp = zs->zs_buf;
1.1 deraadt 453: }
454: return (0);
455: }
456:
457: /*
458: * Decompress read. This routine adapts to the codes in the file building
459: * the "string" table on-the-fly; requiring no table to be stored in the
460: * compressed file. The tables used herein are shared with those of the
461: * compress() routine. See the definitions above.
462: */
1.5 mickey 463: int
1.1 deraadt 464: zread(cookie, rbp, num)
465: void *cookie;
466: char *rbp;
467: int num;
468: {
1.7 mpech 469: u_int count;
1.1 deraadt 470: struct s_zstate *zs;
471: u_char *bp, header[3];
472:
473: if (num == 0)
474: return (0);
475:
476: zs = cookie;
477: count = num;
478: bp = (u_char *)rbp;
1.5 mickey 479: switch (zs->zs_state) {
1.1 deraadt 480: case S_START:
1.5 mickey 481: zs->zs_state = S_MIDDLE;
1.6 mickey 482: zs->zs_bp = zs->zs_buf;
1.1 deraadt 483: break;
484: case S_MIDDLE:
485: goto middle;
486: case S_EOF:
487: goto eof;
488: }
489:
490: /* Check the magic number */
1.5 mickey 491: if (read(zs->zs_fd, header, sizeof(header)) != sizeof(header) ||
492: memcmp(header, z_magic, sizeof(z_magic)) != 0) {
1.1 deraadt 493: errno = EFTYPE;
494: return (-1);
495: }
1.5 mickey 496: zs->zs_maxbits = header[2]; /* Set -b from file. */
497: zs->zs_block_compress = zs->zs_maxbits & BLOCK_MASK;
498: zs->zs_maxbits &= BIT_MASK;
499: zs->zs_maxmaxcode = 1L << zs->zs_maxbits;
500: if (zs->zs_maxbits > BITS) {
1.1 deraadt 501: errno = EFTYPE;
502: return (-1);
503: }
504: /* As above, initialize the first 256 entries in the table. */
1.5 mickey 505: zs->zs_maxcode = MAXCODE(zs->zs_n_bits = INIT_BITS);
506: for (zs->zs_code = 255; zs->zs_code >= 0; zs->zs_code--) {
507: tab_prefixof(zs->zs_code) = 0;
508: tab_suffixof(zs->zs_code) = (u_char) zs->zs_code;
1.1 deraadt 509: }
1.5 mickey 510: zs->zs_free_ent = zs->zs_block_compress ? FIRST : 256;
1.1 deraadt 511:
1.5 mickey 512: zs->zs_finchar = zs->zs_oldcode = getcode(zs);
513: if (zs->zs_oldcode == -1) /* EOF already? */
1.1 deraadt 514: return (0); /* Get out of here */
515:
516: /* First code must be 8 bits = char. */
1.5 mickey 517: *bp++ = (u_char)zs->zs_finchar;
1.1 deraadt 518: count--;
1.5 mickey 519: zs->zs_stackp = de_stack;
1.1 deraadt 520:
1.5 mickey 521: while ((zs->zs_code = getcode(zs)) > -1) {
1.1 deraadt 522:
1.5 mickey 523: if ((zs->zs_code == CLEAR) && zs->zs_block_compress) {
524: for (zs->zs_code = 255; zs->zs_code >= 0;
525: zs->zs_code--)
526: tab_prefixof(zs->zs_code) = 0;
527: zs->zs_clear_flg = 1;
528: zs->zs_free_ent = FIRST - 1;
529: if ((zs->zs_code = getcode(zs)) == -1) /* O, untimely death! */
1.1 deraadt 530: break;
531: }
1.5 mickey 532: zs->zs_incode = zs->zs_code;
1.1 deraadt 533:
534: /* Special case for KwKwK string. */
1.5 mickey 535: if (zs->zs_code >= zs->zs_free_ent) {
536: *zs->zs_stackp++ = zs->zs_finchar;
537: zs->zs_code = zs->zs_oldcode;
1.1 deraadt 538: }
539:
540: /* Generate output characters in reverse order. */
1.5 mickey 541: while (zs->zs_code >= 256) {
542: *zs->zs_stackp++ = tab_suffixof(zs->zs_code);
543: zs->zs_code = tab_prefixof(zs->zs_code);
1.1 deraadt 544: }
1.5 mickey 545: *zs->zs_stackp++ = zs->zs_finchar = tab_suffixof(zs->zs_code);
1.1 deraadt 546:
547: /* And put them out in forward order. */
548: middle: do {
549: if (count-- == 0)
550: return (num);
1.5 mickey 551: *bp++ = *--zs->zs_stackp;
552: } while (zs->zs_stackp > de_stack);
1.1 deraadt 553:
554: /* Generate the new entry. */
1.5 mickey 555: if ((zs->zs_code = zs->zs_free_ent) < zs->zs_maxmaxcode) {
556: tab_prefixof(zs->zs_code) = (u_short) zs->zs_oldcode;
557: tab_suffixof(zs->zs_code) = zs->zs_finchar;
558: zs->zs_free_ent = zs->zs_code + 1;
1.1 deraadt 559: }
560:
561: /* Remember previous code. */
1.5 mickey 562: zs->zs_oldcode = zs->zs_incode;
1.1 deraadt 563: }
1.5 mickey 564: zs->zs_state = S_EOF;
1.1 deraadt 565: eof: return (num - count);
566: }
567:
568: /*-
569: * Read one code from the standard input. If EOF, return -1.
570: * Inputs:
571: * stdin
572: * Outputs:
573: * code or -1 is returned.
574: */
575: static code_int
576: getcode(zs)
1.7 mpech 577: struct s_zstate *zs;
1.1 deraadt 578: {
1.7 mpech 579: code_int gcode;
580: int r_off, bits;
581: u_char *bp;
1.1 deraadt 582:
1.6 mickey 583: if (zs->zs_clear_flg > 0 || zs->zs_offset >= zs->zs_size ||
1.5 mickey 584: zs->zs_free_ent > zs->zs_maxcode) {
1.6 mickey 585:
586: zs->zs_bp += zs->zs_n_bits;
1.1 deraadt 587: /*
588: * If the next entry will be too big for the current gcode
589: * size, then we must increase the size. This implies reading
590: * a new buffer full, too.
591: */
1.5 mickey 592: if (zs->zs_free_ent > zs->zs_maxcode) {
593: zs->zs_n_bits++;
594: if (zs->zs_n_bits == zs->zs_maxbits) /* Won't get any bigger now. */
595: zs->zs_maxcode = zs->zs_maxmaxcode;
1.1 deraadt 596: else
1.5 mickey 597: zs->zs_maxcode = MAXCODE(zs->zs_n_bits);
1.1 deraadt 598: }
1.5 mickey 599: if (zs->zs_clear_flg > 0) {
600: zs->zs_maxcode = MAXCODE(zs->zs_n_bits = INIT_BITS);
601: zs->zs_clear_flg = 0;
1.1 deraadt 602: }
1.6 mickey 603:
604: /* fill the buffer up to the neck */
605: if (zs->zs_bp + zs->zs_n_bits > zs->zs_ebp) {
606: for (bp = zs->zs_buf; zs->zs_bp < zs->zs_ebp;
607: *bp++ = *zs->zs_bp++);
608: if ((bits = read(zs->zs_fd, bp, ZBUFSIZ -
609: (bp - zs->zs_buf))) < 0)
610: return -1;
611: zs->zs_bp = zs->zs_buf;
612: zs->zs_ebp = bp + bits;
613: }
614: zs->zs_offset = 0;
615: zs->zs_size = MIN(zs->zs_n_bits, zs->zs_ebp - zs->zs_bp);
616: if (zs->zs_size == 0)
617: return -1;
1.1 deraadt 618: /* Round size down to integral number of codes. */
1.5 mickey 619: zs->zs_size = (zs->zs_size << 3) - (zs->zs_n_bits - 1);
1.1 deraadt 620: }
1.6 mickey 621:
622: bp = zs->zs_bp;
623: r_off = zs->zs_offset;
1.5 mickey 624: bits = zs->zs_n_bits;
1.1 deraadt 625:
626: /* Get to the first byte. */
627: bp += (r_off >> 3);
628: r_off &= 7;
629:
630: /* Get first part (low order bits). */
631: gcode = (*bp++ >> r_off);
632: bits -= (8 - r_off);
633: r_off = 8 - r_off; /* Now, roffset into gcode word. */
634:
635: /* Get any 8 bit parts in the middle (<=1 for up to 16 bits). */
636: if (bits >= 8) {
637: gcode |= *bp++ << r_off;
638: r_off += 8;
639: bits -= 8;
640: }
641:
642: /* High order bits. */
643: gcode |= (*bp & rmask[bits]) << r_off;
1.6 mickey 644: zs->zs_offset += zs->zs_n_bits;
1.1 deraadt 645:
646: return (gcode);
647: }
648:
649: static int
650: cl_block(zs) /* Table clear for block compress. */
1.7 mpech 651: struct s_zstate *zs;
1.1 deraadt 652: {
1.7 mpech 653: long rat;
1.1 deraadt 654:
1.5 mickey 655: zs->zs_checkpoint = zs->zs_in_count + CHECK_GAP;
1.1 deraadt 656:
1.5 mickey 657: if (zs->zs_in_count > 0x007fffff) { /* Shift will overflow. */
658: rat = zs->zs_bytes_out >> 8;
1.1 deraadt 659: if (rat == 0) /* Don't divide by zero. */
660: rat = 0x7fffffff;
661: else
1.5 mickey 662: rat = zs->zs_in_count / rat;
1.1 deraadt 663: } else
1.5 mickey 664: rat = (zs->zs_in_count << 8) / zs->zs_bytes_out; /* 8 fractional bits. */
665: if (rat > zs->zs_ratio)
666: zs->zs_ratio = rat;
1.1 deraadt 667: else {
1.5 mickey 668: zs->zs_ratio = 0;
669: cl_hash(zs, (count_int) zs->zs_hsize);
670: zs->zs_free_ent = FIRST;
671: zs->zs_clear_flg = 1;
1.1 deraadt 672: if (output(zs, (code_int) CLEAR) == -1)
673: return (-1);
674: }
675: return (0);
676: }
677:
678: static void
679: cl_hash(zs, cl_hsize) /* Reset code table. */
1.7 mpech 680: struct s_zstate *zs;
681: count_int cl_hsize;
1.1 deraadt 682: {
1.7 mpech 683: count_int *htab_p;
684: long i, m1;
1.1 deraadt 685:
686: m1 = -1;
1.5 mickey 687: htab_p = zs->zs_htab + cl_hsize;
1.1 deraadt 688: i = cl_hsize - 16;
689: do { /* Might use Sys V memset(3) here. */
690: *(htab_p - 16) = m1;
691: *(htab_p - 15) = m1;
692: *(htab_p - 14) = m1;
693: *(htab_p - 13) = m1;
694: *(htab_p - 12) = m1;
695: *(htab_p - 11) = m1;
696: *(htab_p - 10) = m1;
697: *(htab_p - 9) = m1;
698: *(htab_p - 8) = m1;
699: *(htab_p - 7) = m1;
700: *(htab_p - 6) = m1;
701: *(htab_p - 5) = m1;
702: *(htab_p - 4) = m1;
703: *(htab_p - 3) = m1;
704: *(htab_p - 2) = m1;
705: *(htab_p - 1) = m1;
706: htab_p -= 16;
707: } while ((i -= 16) >= 0);
708: for (i += 16; i > 0; i--)
709: *--htab_p = m1;
1.3 tholo 710: }
711:
712: FILE *
1.5 mickey 713: zopen(name, mode, bits)
714: const char *name;
715: const char *mode;
716: int bits;
717: {
718: int fd;
719: void *cookie;
720: if ((fd = open(name, (*mode=='r'? O_RDONLY:O_WRONLY|O_CREAT),
721: S_IRUSR|S_IWUSR|S_IRGRP|S_IROTH)) == -1)
722: return NULL;
723: if ((cookie = z_open(fd, mode, bits)) == NULL) {
724: close(fd);
725: return NULL;
726: }
727: return funopen(cookie, (*mode == 'r'?zread:NULL),
728: (*mode == 'w'?zwrite:NULL), NULL, zclose);
729: }
730:
731: void *
732: z_open(fd, mode, bits)
1.3 tholo 733: int fd;
734: const char *mode;
735: int bits;
736: {
1.7 mpech 737: struct s_zstate *zs;
1.3 tholo 738:
1.4 millert 739: if ((mode[0] != 'r' && mode[0] != 'w') || mode[1] != '\0' ||
1.3 tholo 740: bits < 0 || bits > BITS) {
741: errno = EINVAL;
742: return (NULL);
743: }
744:
745: if ((zs = calloc(1, sizeof(struct s_zstate))) == NULL)
746: return (NULL);
747:
1.5 mickey 748: /* User settable max # bits/code. */
749: zs->zs_maxbits = bits ? bits : BITS;
750: /* Should NEVER generate this code. */
751: zs->zs_maxmaxcode = 1 << zs->zs_maxbits;
752: zs->zs_hsize = HSIZE; /* For dynamic table sizing. */
753: zs->zs_free_ent = 0; /* First unused entry. */
754: zs->zs_block_compress = BLOCK_MASK;
755: zs->zs_clear_flg = 0;
756: zs->zs_ratio = 0;
757: zs->zs_checkpoint = CHECK_GAP;
758: zs->zs_in_count = 1; /* Length of input. */
759: zs->zs_out_count = 0; /* # of codes output (for debugging).*/
760: zs->zs_state = S_START;
1.6 mickey 761: zs->zs_offset = 0;
1.5 mickey 762: zs->zs_size = 0;
763: zs->zs_mode = mode[0];
1.6 mickey 764: zs->zs_bp = zs->zs_ebp = zs->zs_buf;
1.3 tholo 765:
1.5 mickey 766: zs->zs_fd = fd;
767: return zs;
1.1 deraadt 768: }
769:
1.5 mickey 770: int
771: z_check_header(fd, sb, ofn)
772: int fd;
773: struct stat *sb;
774: const char *ofn;
1.1 deraadt 775: {
1.5 mickey 776: int f;
777: u_char buf[sizeof(z_magic)];
778: off_t off = lseek(fd, 0, SEEK_CUR);
1.1 deraadt 779:
1.5 mickey 780: f = (read(fd, buf, sizeof(buf)) == sizeof(buf) &&
781: !memcmp(buf, z_magic, sizeof(buf)));
1.1 deraadt 782:
1.5 mickey 783: lseek (fd, off, SEEK_SET);
1.1 deraadt 784:
1.5 mickey 785: return f;
1.1 deraadt 786: }
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