1 /* vi: set sw=4 ts=4: */
3 * Gzip implementation for busybox
5 * Based on GNU gzip Copyright (C) 1992-1993 Jean-loup Gailly.
7 * Originally adjusted for busybox by Charles P. Wright <cpw@unix.asb.com>
8 * "this is a stripped down version of gzip I put into busybox, it does
9 * only standard in to standard out with -9 compression. It also requires
10 * the zcat module for some important functions."
12 * Adjusted further by Erik Andersen <andersen@lineo.com>, <andersee@debian.org>
13 * to support files as well as stdin/stdout, and to generally behave itself wrt
14 * command line handling.
16 * This program is free software; you can redistribute it and/or modify
17 * it under the terms of the GNU General Public License as published by
18 * the Free Software Foundation; either version 2 of the License, or
19 * (at your option) any later version.
21 * This program is distributed in the hope that it will be useful,
22 * but WITHOUT ANY WARRANTY; without even the implied warranty of
23 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
24 * General Public License for more details.
26 * You should have received a copy of the GNU General Public License
27 * along with this program; if not, write to the Free Software
28 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
33 #define BB_DECLARE_EXTERN
34 #define bb_need_memory_exhausted
37 /* These defines are very important for BusyBox. Without these,
38 * huge chunks of ram are pre-allocated making the BusyBox bss
39 * size Freaking Huge(tm), which is a bad thing.*/
44 static const char gzip_usage[] =
45 "gzip [OPTION]... FILE\n"
46 #ifndef BB_FEATURE_TRIVIAL_HELP
47 "\nCompress FILE with maximum compression.\n"
48 "When FILE is '-', reads standard input. Implies -c.\n\n"
51 "\t-c\tWrite output to standard output instead of FILE.gz\n"
56 /* I don't like nested includes, but the string and io functions are used
61 #define memzero(s, n) memset ((void *)(s), 0, (n))
64 # define RETSIGTYPE void
69 typedef unsigned char uch;
70 typedef unsigned short ush;
71 typedef unsigned long ulg;
73 /* Return codes from gzip */
78 /* Compression methods (see algorithm.doc) */
83 /* methods 4 to 7 reserved */
86 extern int method; /* compression method */
88 /* To save memory for 16 bit systems, some arrays are overlaid between
89 * the various modules:
90 * deflate: prev+head window d_buf l_buf outbuf
91 * unlzw: tab_prefix tab_suffix stack inbuf outbuf
92 * inflate: window inbuf
93 * unpack: window inbuf prefix_len
94 * unlzh: left+right window c_table inbuf c_len
95 * For compression, input is done in window[]. For decompression, output
96 * is done in window except for unlzw.
101 # define INBUFSIZ 0x2000 /* input buffer size */
103 # define INBUFSIZ 0x8000 /* input buffer size */
106 #define INBUF_EXTRA 64 /* required by unlzw() */
110 # define OUTBUFSIZ 8192 /* output buffer size */
112 # define OUTBUFSIZ 16384 /* output buffer size */
115 #define OUTBUF_EXTRA 2048 /* required by unlzw() */
119 # define DIST_BUFSIZE 0x2000 /* buffer for distances, see trees.c */
121 # define DIST_BUFSIZE 0x8000 /* buffer for distances, see trees.c */
126 # define EXTERN(type, array) extern type * array
127 # define DECLARE(type, array, size) type * array
128 # define ALLOC(type, array, size) { \
129 array = (type*)calloc((size_t)(((size)+1L)/2), 2*sizeof(type)); \
130 if (array == NULL) errorMsg(memory_exhausted, "gzip"); \
132 # define FREE(array) {if (array != NULL) free(array), array=NULL;}
134 # define EXTERN(type, array) extern type array[]
135 # define DECLARE(type, array, size) type array[size]
136 # define ALLOC(type, array, size)
140 EXTERN(uch, inbuf); /* input buffer */
141 EXTERN(uch, outbuf); /* output buffer */
142 EXTERN(ush, d_buf); /* buffer for distances, see trees.c */
143 EXTERN(uch, window); /* Sliding window and suffix table (unlzw) */
144 #define tab_suffix window
146 # define tab_prefix prev /* hash link (see deflate.c) */
147 # define head (prev+WSIZE) /* hash head (see deflate.c) */
148 EXTERN(ush, tab_prefix); /* prefix code (see unlzw.c) */
150 # define tab_prefix0 prev
151 # define head tab_prefix1
152 EXTERN(ush, tab_prefix0); /* prefix for even codes */
153 EXTERN(ush, tab_prefix1); /* prefix for odd codes */
156 extern unsigned insize; /* valid bytes in inbuf */
157 extern unsigned inptr; /* index of next byte to be processed in inbuf */
158 extern unsigned outcnt; /* bytes in output buffer */
160 extern long bytes_in; /* number of input bytes */
161 extern long bytes_out; /* number of output bytes */
162 extern long header_bytes; /* number of bytes in gzip header */
164 #define isize bytes_in
165 /* for compatibility with old zip sources (to be cleaned) */
167 extern int ifd; /* input file descriptor */
168 extern int ofd; /* output file descriptor */
169 extern char ifname[]; /* input file name or "stdin" */
170 extern char ofname[]; /* output file name or "stdout" */
171 extern char *progname; /* program name */
173 extern long time_stamp; /* original time stamp (modification time) */
174 extern long ifile_size; /* input file size, -1 for devices (debug only) */
176 typedef int file_t; /* Do not use stdio */
178 #define NO_FILE (-1) /* in memory compression */
181 #define PACK_MAGIC "\037\036" /* Magic header for packed files */
182 #define GZIP_MAGIC "\037\213" /* Magic header for gzip files, 1F 8B */
183 #define OLD_GZIP_MAGIC "\037\236" /* Magic header for gzip 0.5 = freeze 1.x */
184 #define LZH_MAGIC "\037\240" /* Magic header for SCO LZH Compress files */
185 #define PKZIP_MAGIC "\120\113\003\004" /* Magic header for pkzip files */
188 #define ASCII_FLAG 0x01 /* bit 0 set: file probably ascii text */
189 #define CONTINUATION 0x02 /* bit 1 set: continuation of multi-part gzip file */
190 #define EXTRA_FIELD 0x04 /* bit 2 set: extra field present */
191 #define ORIG_NAME 0x08 /* bit 3 set: original file name present */
192 #define COMMENT 0x10 /* bit 4 set: file comment present */
193 #define ENCRYPTED 0x20 /* bit 5 set: file is encrypted */
194 #define RESERVED 0xC0 /* bit 6,7: reserved */
196 /* internal file attribute */
197 #define UNKNOWN 0xffff
202 # define WSIZE 0x8000 /* window size--must be a power of two, and */
203 #endif /* at least 32K for zip's deflate method */
206 #define MAX_MATCH 258
207 /* The minimum and maximum match lengths */
209 #define MIN_LOOKAHEAD (MAX_MATCH+MIN_MATCH+1)
210 /* Minimum amount of lookahead, except at the end of the input file.
211 * See deflate.c for comments about the MIN_MATCH+1.
214 #define MAX_DIST (WSIZE-MIN_LOOKAHEAD)
215 /* In order to simplify the code, particularly on 16 bit machines, match
216 * distances are limited to MAX_DIST instead of WSIZE.
219 extern int decrypt; /* flag to turn on decryption */
220 extern int exit_code; /* program exit code */
221 extern int verbose; /* be verbose (-v) */
222 extern int quiet; /* be quiet (-q) */
223 extern int test; /* check .z file integrity */
224 extern int save_orig_name; /* set if original name must be saved */
226 #define get_byte() (inptr < insize ? inbuf[inptr++] : fill_inbuf(0))
227 #define try_byte() (inptr < insize ? inbuf[inptr++] : fill_inbuf(1))
229 /* put_byte is used for the compressed output, put_ubyte for the
230 * uncompressed output. However unlzw() uses window for its
231 * suffix table instead of its output buffer, so it does not use put_ubyte
232 * (to be cleaned up).
234 #define put_byte(c) {outbuf[outcnt++]=(uch)(c); if (outcnt==OUTBUFSIZ)\
236 #define put_ubyte(c) {window[outcnt++]=(uch)(c); if (outcnt==WSIZE)\
239 /* Output a 16 bit value, lsb first */
240 #define put_short(w) \
241 { if (outcnt < OUTBUFSIZ-2) { \
242 outbuf[outcnt++] = (uch) ((w) & 0xff); \
243 outbuf[outcnt++] = (uch) ((ush)(w) >> 8); \
245 put_byte((uch)((w) & 0xff)); \
246 put_byte((uch)((ush)(w) >> 8)); \
250 /* Output a 32 bit value to the bit stream, lsb first */
251 #define put_long(n) { \
252 put_short((n) & 0xffff); \
253 put_short(((ulg)(n)) >> 16); \
256 #define seekable() 0 /* force sequential output */
257 #define translate_eol 0 /* no option -a yet */
259 #define tolow(c) (isupper(c) ? (c)-'A'+'a' : (c)) /* force to lower case */
261 /* Macros for getting two-byte and four-byte header values */
262 #define SH(p) ((ush)(uch)((p)[0]) | ((ush)(uch)((p)[1]) << 8))
263 #define LG(p) ((ulg)(SH(p)) | ((ulg)(SH((p)+2)) << 16))
265 /* Diagnostic functions */
267 # define Assert(cond,msg) {if(!(cond)) errorMsg(msg);}
268 # define Trace(x) fprintf x
269 # define Tracev(x) {if (verbose) fprintf x ;}
270 # define Tracevv(x) {if (verbose>1) fprintf x ;}
271 # define Tracec(c,x) {if (verbose && (c)) fprintf x ;}
272 # define Tracecv(c,x) {if (verbose>1 && (c)) fprintf x ;}
274 # define Assert(cond,msg)
279 # define Tracecv(c,x)
282 #define WARN(msg) {if (!quiet) fprintf msg ; \
283 if (exit_code == OK) exit_code = WARNING;}
285 #define do_exit(c) exit(c)
289 extern int zip (int in, int out);
290 extern int file_read (char *buf, unsigned size);
293 extern int unzip (int in, int out);
294 extern int check_zipfile (int in);
297 extern int unpack (int in, int out);
300 extern int unlzh (int in, int out);
303 RETSIGTYPE abort_gzip (void);
306 void lm_init (ush * flags);
310 void ct_init (ush * attr, int *method);
311 int ct_tally (int dist, int lc);
312 ulg flush_block (char *buf, ulg stored_len, int eof);
315 void bi_init (file_t zipfile);
316 void send_bits (int value, int length);
317 unsigned bi_reverse (unsigned value, int length);
318 void bi_windup (void);
319 void copy_block (char *buf, unsigned len, int header);
320 extern int (*read_buf) (char *buf, unsigned size);
323 extern int copy (int in, int out);
324 extern ulg updcrc (uch * s, unsigned n);
325 extern void clear_bufs (void);
326 extern int fill_inbuf (int eof_ok);
327 extern void flush_outbuf (void);
328 extern void flush_window (void);
329 extern void write_buf (int fd, void * buf, unsigned cnt);
330 extern char *strlwr (char *s);
331 extern char *add_envopt (int *argcp, char ***argvp, char *env);
332 extern void read_error (void);
333 extern void write_error (void);
334 extern void display_ratio (long num, long den, FILE * file);
337 extern int inflate (void);
339 /* lzw.h -- define the lzw functions.
340 * Copyright (C) 1992-1993 Jean-loup Gailly.
341 * This is free software; you can redistribute it and/or modify it under the
342 * terms of the GNU General Public License, see the file COPYING.
345 #if !defined(OF) && defined(lint)
352 #define INIT_BITS 9 /* Initial number of bits per code */
354 #define BIT_MASK 0x1f /* Mask for 'number of compression bits' */
355 /* Mask 0x20 is reserved to mean a fourth header byte, and 0x40 is free.
356 * It's a pity that old uncompress does not check bit 0x20. That makes
357 * extension of the format actually undesirable because old compress
358 * would just crash on the new format instead of giving a meaningful
359 * error message. It does check the number of bits, but it's more
360 * helpful to say "unsupported format, get a new version" than
361 * "can only handle 16 bits".
364 #define BLOCK_MODE 0x80
365 /* Block compression: if table is full and compression rate is dropping,
366 * clear the dictionary.
369 #define LZW_RESERVED 0x60 /* reserved bits */
371 #define CLEAR 256 /* flush the dictionary */
372 #define FIRST (CLEAR+1) /* first free entry */
374 extern int maxbits; /* max bits per code for LZW */
375 extern int block_mode; /* block compress mode -C compatible with 2.0 */
377 /* revision.h -- define the version number
378 * Copyright (C) 1992-1993 Jean-loup Gailly.
379 * This is free software; you can redistribute it and/or modify it under the
380 * terms of the GNU General Public License, see the file COPYING.
383 #define VERSION "1.2.4"
385 #define REVDATE "18 Aug 93"
387 /* This version does not support compression into old compress format: */
392 /* tailor.h -- target dependent definitions
393 * Copyright (C) 1992-1993 Jean-loup Gailly.
394 * This is free software; you can redistribute it and/or modify it under the
395 * terms of the GNU General Public License, see the file COPYING.
398 /* The target dependent definitions should be defined here only.
399 * The target dependent functions should be defined in tailor.c.
403 #if defined(__MSDOS__) && !defined(MSDOS)
407 #if defined(__OS2__) && !defined(OS2)
411 #if defined(OS2) && defined(MSDOS) /* MS C under OS/2 */
417 /* DJGPP version 1.09+ on MS-DOS.
418 * The DJGPP 1.09 stat() function must be upgraded before gzip will
420 * No need for DIRENT, since <unistd.h> defines POSIX_SOURCE which
434 # define HAVE_SYS_UTIME_H
438 # define PATH_SEP2 '\\'
439 # define PATH_SEP3 ':'
440 # define MAX_PATH_LEN 128
441 # define NO_MULTIPLE_DOTS
442 # define MAX_EXT_CHARS 3
443 # define Z_SUFFIX "z"
446 # define STDC_HEADERS
447 # define NO_SIZE_CHECK
448 # define casemap(c) tolow(c) /* Force file names to lower case */
450 # define OS_CODE 0x00
451 # define SET_BINARY_MODE(fd) setmode(fd, O_BINARY)
452 # if !defined(NO_ASM) && !defined(ASMV)
460 # define PATH_SEP2 '\\'
461 # define PATH_SEP3 ':'
462 # define MAX_PATH_LEN 260
464 # define NO_MULTIPLE_DOTS
465 # define MAX_EXT_CHARS 3
466 # define Z_SUFFIX "z"
467 # define casemap(c) tolow(c)
471 # define STDC_HEADERS
473 # define OS_CODE 0x06
474 # define SET_BINARY_MODE(fd) setmode(fd, O_BINARY)
476 # define HAVE_SYS_UTIME_H
483 # define HAVE_SYS_UTIME_H
486 # define EXPAND(argc,argv) \
487 {_response(&argc, &argv); _wildcard(&argc, &argv);}
496 # define EXPAND(argc,argv) \
497 {response_expand(&argc, &argv);}
501 #ifdef WIN32 /* Windows NT */
502 # define HAVE_SYS_UTIME_H
504 # define PATH_SEP2 '\\'
505 # define PATH_SEP3 ':'
506 # define MAX_PATH_LEN 260
509 # define STDC_HEADERS
510 # define SET_BINARY_MODE(fd) setmode(fd, O_BINARY)
514 # define NO_MULTIPLE_DOTS
515 # define MAX_EXT_CHARS 3
516 # define Z_SUFFIX "z"
517 # define casemap(c) tolow(c) /* Force file names to lower case */
519 # define OS_CODE 0x0b
526 /* Turbo C 2.0 does not accept static allocations of large arrays */
527 void *fcalloc(unsigned items, unsigned size);
528 void fcfree(void *ptr);
531 # define fcalloc(nitems,itemsize) halloc((long)(nitems),(itemsize))
532 # define fcfree(ptr) hfree(ptr)
536 # define fcalloc(items,size) calloc((items),(size))
538 # define fcalloc(items,size) malloc((size_t)(items)*(size_t)(size))
540 # define fcfree(ptr) free(ptr)
543 #if defined(VAXC) || defined(VMS)
544 # define PATH_SEP ']'
545 # define PATH_SEP2 ':'
546 # define SUFFIX_SEP ';'
547 # define NO_MULTIPLE_DOTS
548 # define Z_SUFFIX "-gz"
550 # define casemap(c) tolow(c)
551 # define OS_CODE 0x02
552 # define OPTIONS_VAR "GZIP_OPT"
553 # define STDC_HEADERS
555 # define EXPAND(argc,argv) vms_expand_args(&argc,&argv);
557 # define unlink delete
565 # define PATH_SEP2 ':'
566 # define STDC_HEADERS
567 # define OS_CODE 0x01
571 # define HAVE_UNISTD_H
573 # define NO_STDIN_FSTAT
578 # include <fcntl.h> /* for read() and write() */
579 # define direct dirent
580 extern void _expand_args(int *argc, char ***argv);
582 # define EXPAND(argc,argv) _expand_args(&argc,&argv);
583 # undef O_BINARY /* disable useless --ascii option */
587 #if defined(ATARI) || defined(atarist)
588 # ifndef STDC_HEADERS
589 # define STDC_HEADERS
590 # define HAVE_UNISTD_H
594 # define OS_CODE 0x05
596 # define PATH_SEP2 '\\'
597 # define PATH_SEP3 ':'
598 # define MAX_PATH_LEN 128
599 # define NO_MULTIPLE_DOTS
600 # define MAX_EXT_CHARS 3
601 # define Z_SUFFIX "z"
603 # define casemap(c) tolow(c) /* Force file names to lower case */
609 # define PATH_SEP ':'
612 # define NO_STDIN_FSTAT
615 # define chmod(file, mode) (0)
616 # define OPEN(name, flags, mode) open(name, flags)
617 # define OS_CODE 0x07
619 # define isatty(fd) ((fd) <= 2)
623 #ifdef __50SERIES /* Prime/PRIMOS */
624 # define PATH_SEP '>'
625 # define STDC_HEADERS
630 # define NO_STDIN_FSTAT
631 # define NO_SIZE_CHECK
634 # define casemap(c) tolow(c) /* Force file names to lower case */
635 # define put_char(c) put_byte((c) & 0x7F)
636 # define get_char(c) ascii2pascii(get_byte())
637 # define OS_CODE 0x0F /* temporary, subject to change */
639 # undef SIGTERM /* We don't want a signal handler for SIGTERM */
643 #if defined(pyr) && !defined(NOMEMCPY) /* Pyramid */
644 # define NOMEMCPY /* problem with overlapping copies */
648 # define OS_CODE 0x0a
652 # define NO_ST_INO /* don't rely on inode numbers */
656 /* Common defaults */
659 # define OS_CODE 0x03 /* assume Unix */
663 # define PATH_SEP '/'
667 # define casemap(c) (c)
671 # define OPTIONS_VAR "GZIP"
675 # define Z_SUFFIX ".gz"
679 # define MAX_SUFFIX MAX_EXT_CHARS
681 # define MAX_SUFFIX 30
684 #ifndef MAKE_LEGAL_NAME
685 # ifdef NO_MULTIPLE_DOTS
686 # define MAKE_LEGAL_NAME(name) make_simple_name(name)
688 # define MAKE_LEGAL_NAME(name)
694 /* keep at least MIN_PART chars between dots in a file name. */
698 # define EXPAND(argc,argv)
705 #ifndef SET_BINARY_MODE
706 # define SET_BINARY_MODE(fd)
710 # define OPEN(name, flags, mode) open(name, flags, mode)
714 # define get_char() get_byte()
718 # define put_char(c) put_byte(c)
720 /* bits.c -- output variable-length bit strings
721 * Copyright (C) 1992-1993 Jean-loup Gailly
722 * This is free software; you can redistribute it and/or modify it under the
723 * terms of the GNU General Public License, see the file COPYING.
730 * Output variable-length bit strings. Compression can be done
731 * to a file or to memory. (The latter is not supported in this version.)
735 * The PKZIP "deflate" file format interprets compressed file data
736 * as a sequence of bits. Multi-bit strings in the file may cross
737 * byte boundaries without restriction.
739 * The first bit of each byte is the low-order bit.
741 * The routines in this file allow a variable-length bit value to
742 * be output right-to-left (useful for literal values). For
743 * left-to-right output (useful for code strings from the tree routines),
744 * the bits must have been reversed first with bi_reverse().
746 * For in-memory compression, the compressed bit stream goes directly
747 * into the requested output buffer. The input data is read in blocks
748 * by the mem_read() function. The buffer is limited to 64K on 16 bit
753 * void bi_init (FILE *zipfile)
754 * Initialize the bit string routines.
756 * void send_bits (int value, int length)
757 * Write out a bit string, taking the source bits right to
760 * int bi_reverse (int value, int length)
761 * Reverse the bits of a bit string, taking the source bits left to
762 * right and emitting them right to left.
764 * void bi_windup (void)
765 * Write out any remaining bits in an incomplete byte.
767 * void copy_block(char *buf, unsigned len, int header)
768 * Copy a stored block to the zip file, storing first the length and
769 * its one's complement if requested.
777 /* ===========================================================================
778 * Local data used by the "bit string" routines.
781 local file_t zfile; /* output gzip file */
783 local unsigned short bi_buf;
785 /* Output buffer. bits are inserted starting at the bottom (least significant
789 #define Buf_size (8 * 2*sizeof(char))
790 /* Number of bits used within bi_buf. (bi_buf might be implemented on
791 * more than 16 bits on some systems.)
796 /* Number of valid bits in bi_buf. All bits above the last valid bit
800 int (*read_buf) (char *buf, unsigned size);
802 /* Current input function. Set to mem_read for in-memory compression */
805 ulg bits_sent; /* bit length of the compressed data */
808 /* ===========================================================================
809 * Initialize the bit string routines.
811 void bi_init(zipfile)
812 file_t zipfile; /* output zip file, NO_FILE for in-memory compression */
821 /* Set the defaults for file compression. They are set by memcompress
822 * for in-memory compression.
824 if (zfile != NO_FILE) {
825 read_buf = file_read;
829 /* ===========================================================================
830 * Send a value on a given number of bits.
831 * IN assertion: length <= 16 and value fits in length bits.
833 void send_bits(value, length)
834 int value; /* value to send */
835 int length; /* number of bits */
838 Tracev((stderr, " l %2d v %4x ", length, value));
839 Assert(length > 0 && length <= 15, "invalid length");
840 bits_sent += (ulg) length;
842 /* If not enough room in bi_buf, use (valid) bits from bi_buf and
843 * (16 - bi_valid) bits from value, leaving (width - (16-bi_valid))
844 * unused bits in value.
846 if (bi_valid > (int) Buf_size - length) {
847 bi_buf |= (value << bi_valid);
849 bi_buf = (ush) value >> (Buf_size - bi_valid);
850 bi_valid += length - Buf_size;
852 bi_buf |= value << bi_valid;
857 /* ===========================================================================
858 * Reverse the first len bits of a code, using straightforward code (a faster
859 * method would use a table)
860 * IN assertion: 1 <= len <= 15
862 unsigned bi_reverse(code, len)
863 unsigned code; /* the value to invert */
864 int len; /* its bit length */
866 register unsigned res = 0;
870 code >>= 1, res <<= 1;
875 /* ===========================================================================
876 * Write out any remaining bits in an incomplete byte.
882 } else if (bi_valid > 0) {
888 bits_sent = (bits_sent + 7) & ~7;
892 /* ===========================================================================
893 * Copy a stored block to the zip file, storing first the length and its
894 * one's complement if requested.
896 void copy_block(buf, len, header)
897 char *buf; /* the input data */
898 unsigned len; /* its length */
899 int header; /* true if block header must be written */
901 bi_windup(); /* align on byte boundary */
904 put_short((ush) len);
905 put_short((ush) ~ len);
911 bits_sent += (ulg) len << 3;
924 /* deflate.c -- compress data using the deflation algorithm
925 * Copyright (C) 1992-1993 Jean-loup Gailly
926 * This is free software; you can redistribute it and/or modify it under the
927 * terms of the GNU General Public License, see the file COPYING.
933 * Identify new text as repetitions of old text within a fixed-
934 * length sliding window trailing behind the new text.
938 * The "deflation" process depends on being able to identify portions
939 * of the input text which are identical to earlier input (within a
940 * sliding window trailing behind the input currently being processed).
942 * The most straightforward technique turns out to be the fastest for
943 * most input files: try all possible matches and select the longest.
944 * The key feature of this algorithm is that insertions into the string
945 * dictionary are very simple and thus fast, and deletions are avoided
946 * completely. Insertions are performed at each input character, whereas
947 * string matches are performed only when the previous match ends. So it
948 * is preferable to spend more time in matches to allow very fast string
949 * insertions and avoid deletions. The matching algorithm for small
950 * strings is inspired from that of Rabin & Karp. A brute force approach
951 * is used to find longer strings when a small match has been found.
952 * A similar algorithm is used in comic (by Jan-Mark Wams) and freeze
953 * (by Leonid Broukhis).
954 * A previous version of this file used a more sophisticated algorithm
955 * (by Fiala and Greene) which is guaranteed to run in linear amortized
956 * time, but has a larger average cost, uses more memory and is patented.
957 * However the F&G algorithm may be faster for some highly redundant
958 * files if the parameter max_chain_length (described below) is too large.
962 * The idea of lazy evaluation of matches is due to Jan-Mark Wams, and
963 * I found it in 'freeze' written by Leonid Broukhis.
964 * Thanks to many info-zippers for bug reports and testing.
968 * APPNOTE.TXT documentation file in PKZIP 1.93a distribution.
970 * A description of the Rabin and Karp algorithm is given in the book
971 * "Algorithms" by R. Sedgewick, Addison-Wesley, p252.
973 * Fiala,E.R., and Greene,D.H.
974 * Data Compression with Finite Windows, Comm.ACM, 32,4 (1989) 490-595
978 * void lm_init (int pack_level, ush *flags)
979 * Initialize the "longest match" routines for a new file
982 * Processes a new input file and return its compressed length. Sets
983 * the compressed length, crc, deflate flags and internal file
989 /* ===========================================================================
990 * Configuration parameters
993 /* Compile with MEDIUM_MEM to reduce the memory requirements or
994 * with SMALL_MEM to use as little memory as possible. Use BIG_MEM if the
995 * entire input file can be held in memory (not possible on 16 bit systems).
996 * Warning: defining these symbols affects HASH_BITS (see below) and thus
997 * affects the compression ratio. The compressed output
998 * is still correct, and might even be smaller in some cases.
1002 # define HASH_BITS 13 /* Number of bits used to hash strings */
1005 # define HASH_BITS 14
1008 # define HASH_BITS 15
1009 /* For portability to 16 bit machines, do not use values above 15. */
1012 /* To save space (see unlzw.c), we overlay prev+head with tab_prefix and
1013 * window with tab_suffix. Check that we can do this:
1015 #if (WSIZE<<1) > (1<<BITS)
1016 error:cannot overlay window with tab_suffix and prev with tab_prefix0
1018 #if HASH_BITS > BITS-1
1019 error:cannot overlay head with tab_prefix1
1021 #define HASH_SIZE (unsigned)(1<<HASH_BITS)
1022 #define HASH_MASK (HASH_SIZE-1)
1023 #define WMASK (WSIZE-1)
1024 /* HASH_SIZE and WSIZE must be powers of two */
1026 /* Tail of hash chains */
1029 /* speed options for the general purpose bit flag */
1031 # define TOO_FAR 4096
1033 /* Matches of length 3 are discarded if their distance exceeds TOO_FAR */
1034 /* ===========================================================================
1035 * Local data used by the "longest match" routines.
1038 typedef unsigned IPos;
1040 /* A Pos is an index in the character window. We use short instead of int to
1041 * save space in the various tables. IPos is used only for parameter passing.
1044 /* DECLARE(uch, window, 2L*WSIZE); */
1045 /* Sliding window. Input bytes are read into the second half of the window,
1046 * and move to the first half later to keep a dictionary of at least WSIZE
1047 * bytes. With this organization, matches are limited to a distance of
1048 * WSIZE-MAX_MATCH bytes, but this ensures that IO is always
1049 * performed with a length multiple of the block size. Also, it limits
1050 * the window size to 64K, which is quite useful on MSDOS.
1051 * To do: limit the window size to WSIZE+BSZ if SMALL_MEM (the code would
1052 * be less efficient).
1055 /* DECLARE(Pos, prev, WSIZE); */
1056 /* Link to older string with same hash index. To limit the size of this
1057 * array to 64K, this link is maintained only for the last 32K strings.
1058 * An index in this array is thus a window index modulo 32K.
1061 /* DECLARE(Pos, head, 1<<HASH_BITS); */
1062 /* Heads of the hash chains or NIL. */
1064 ulg window_size = (ulg) 2 * WSIZE;
1066 /* window size, 2*WSIZE except for MMAP or BIG_MEM, where it is the
1067 * input file length plus MIN_LOOKAHEAD.
1072 /* window position at the beginning of the current output block. Gets
1073 * negative when the window is moved backwards.
1076 local unsigned ins_h; /* hash index of string to be inserted */
1078 #define H_SHIFT ((HASH_BITS+MIN_MATCH-1)/MIN_MATCH)
1079 /* Number of bits by which ins_h and del_h must be shifted at each
1080 * input step. It must be such that after MIN_MATCH steps, the oldest
1081 * byte no longer takes part in the hash key, that is:
1082 * H_SHIFT * MIN_MATCH >= HASH_BITS
1085 unsigned int near prev_length;
1087 /* Length of the best match at previous step. Matches not greater than this
1088 * are discarded. This is used in the lazy match evaluation.
1091 unsigned near strstart; /* start of string to insert */
1092 unsigned near match_start; /* start of matching string */
1093 local int eofile; /* flag set at end of input file */
1094 local unsigned lookahead; /* number of valid bytes ahead in window */
1096 unsigned near max_chain_length;
1098 /* To speed up deflation, hash chains are never searched beyond this length.
1099 * A higher limit improves compression ratio but degrades the speed.
1102 local unsigned int max_lazy_match;
1104 /* Attempt to find a better match only when the current match is strictly
1105 * smaller than this value. This mechanism is used only for compression
1108 #define max_insert_length max_lazy_match
1109 /* Insert new strings in the hash table only if the match length
1110 * is not greater than this length. This saves time but degrades compression.
1111 * max_insert_length is used only for compression levels <= 3.
1114 unsigned near good_match;
1116 /* Use a faster search when the previous match is longer than this */
1119 /* Values for max_lazy_match, good_match and max_chain_length, depending on
1120 * the desired pack level (0..9). The values given below have been tuned to
1121 * exclude worst case performance for pathological files. Better values may be
1122 * found for specific files.
1125 typedef struct config {
1126 ush good_length; /* reduce lazy search above this match length */
1127 ush max_lazy; /* do not perform lazy search above this match length */
1128 ush nice_length; /* quit search above this match length */
1133 # define nice_match MAX_MATCH
1135 int near nice_match; /* Stop searching when current match exceeds this */
1138 local config configuration_table =
1139 /* 9 */ { 32, 258, 258, 4096 };
1140 /* maximum compression */
1142 /* Note: the deflate() code requires max_lazy >= MIN_MATCH and max_chain >= 4
1143 * For deflate_fast() (levels <= 3) good is ignored and lazy has a different
1148 /* result of memcmp for equal strings */
1150 /* ===========================================================================
1151 * Prototypes for local functions.
1153 local void fill_window (void);
1155 int longest_match (IPos cur_match);
1158 void match_init (void); /* asm code initialization */
1162 local void check_match (IPos start, IPos match, int length);
1165 /* ===========================================================================
1166 * Update a hash value with the given input byte
1167 * IN assertion: all calls to to UPDATE_HASH are made with consecutive
1168 * input characters, so that a running hash key can be computed from the
1169 * previous key instead of complete recalculation each time.
1171 #define UPDATE_HASH(h,c) (h = (((h)<<H_SHIFT) ^ (c)) & HASH_MASK)
1173 /* ===========================================================================
1174 * Insert string s in the dictionary and set match_head to the previous head
1175 * of the hash chain (the most recent string with same hash key). Return
1176 * the previous length of the hash chain.
1177 * IN assertion: all calls to to INSERT_STRING are made with consecutive
1178 * input characters and the first MIN_MATCH bytes of s are valid
1179 * (except for the last MIN_MATCH-1 bytes of the input file).
1181 #define INSERT_STRING(s, match_head) \
1182 (UPDATE_HASH(ins_h, window[(s) + MIN_MATCH-1]), \
1183 prev[(s) & WMASK] = match_head = head[ins_h], \
1186 /* ===========================================================================
1187 * Initialize the "longest match" routines for a new file
1190 ush *flags; /* general purpose bit flag */
1192 register unsigned j;
1194 /* Initialize the hash table. */
1195 #if defined(MAXSEG_64K) && HASH_BITS == 15
1196 for (j = 0; j < HASH_SIZE; j++)
1199 memzero((char *) head, HASH_SIZE * sizeof(*head));
1201 /* prev will be initialized on the fly */
1203 /* Set the default configuration parameters:
1205 max_lazy_match = configuration_table.max_lazy;
1206 good_match = configuration_table.good_length;
1208 nice_match = configuration_table.nice_length;
1210 max_chain_length = configuration_table.max_chain;
1212 /* ??? reduce max_chain_length for binary files */
1217 match_init(); /* initialize the asm code */
1220 lookahead = read_buf((char *) window,
1221 sizeof(int) <= 2 ? (unsigned) WSIZE : 2 * WSIZE);
1223 if (lookahead == 0 || lookahead == (unsigned) EOF) {
1224 eofile = 1, lookahead = 0;
1228 /* Make sure that we always have enough lookahead. This is important
1229 * if input comes from a device such as a tty.
1231 while (lookahead < MIN_LOOKAHEAD && !eofile)
1235 for (j = 0; j < MIN_MATCH - 1; j++)
1236 UPDATE_HASH(ins_h, window[j]);
1237 /* If lookahead < MIN_MATCH, ins_h is garbage, but this is
1238 * not important since only literal bytes will be emitted.
1242 /* ===========================================================================
1243 * Set match_start to the longest match starting at the given string and
1244 * return its length. Matches shorter or equal to prev_length are discarded,
1245 * in which case the result is equal to prev_length and match_start is
1247 * IN assertions: cur_match is the head of the hash chain for the current
1248 * string (strstart) and its distance is <= MAX_DIST, and prev_length >= 1
1251 /* For MSDOS, OS/2 and 386 Unix, an optimized version is in match.asm or
1252 * match.s. The code is functionally equivalent, so you can use the C version
1255 int longest_match(cur_match)
1256 IPos cur_match; /* current match */
1258 unsigned chain_length = max_chain_length; /* max hash chain length */
1259 register uch *scan = window + strstart; /* current string */
1260 register uch *match; /* matched string */
1261 register int len; /* length of current match */
1262 int best_len = prev_length; /* best match length so far */
1265 strstart > (IPos) MAX_DIST ? strstart - (IPos) MAX_DIST : NIL;
1266 /* Stop when cur_match becomes <= limit. To simplify the code,
1267 * we prevent matches with the string of window index 0.
1270 /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16.
1271 * It is easy to get rid of this optimization if necessary.
1273 #if HASH_BITS < 8 || MAX_MATCH != 258
1274 error:Code too clever
1277 /* Compare two bytes at a time. Note: this is not always beneficial.
1278 * Try with and without -DUNALIGNED_OK to check.
1280 register uch *strend = window + strstart + MAX_MATCH - 1;
1281 register ush scan_start = *(ush *) scan;
1282 register ush scan_end = *(ush *) (scan + best_len - 1);
1284 register uch *strend = window + strstart + MAX_MATCH;
1285 register uch scan_end1 = scan[best_len - 1];
1286 register uch scan_end = scan[best_len];
1289 /* Do not waste too much time if we already have a good match: */
1290 if (prev_length >= good_match) {
1293 Assert(strstart <= window_size - MIN_LOOKAHEAD,
1294 "insufficient lookahead");
1297 Assert(cur_match < strstart, "no future");
1298 match = window + cur_match;
1300 /* Skip to next match if the match length cannot increase
1301 * or if the match length is less than 2:
1303 #if (defined(UNALIGNED_OK) && MAX_MATCH == 258)
1304 /* This code assumes sizeof(unsigned short) == 2. Do not use
1305 * UNALIGNED_OK if your compiler uses a different size.
1307 if (*(ush *) (match + best_len - 1) != scan_end ||
1308 *(ush *) match != scan_start)
1311 /* It is not necessary to compare scan[2] and match[2] since they are
1312 * always equal when the other bytes match, given that the hash keys
1313 * are equal and that HASH_BITS >= 8. Compare 2 bytes at a time at
1314 * strstart+3, +5, ... up to strstart+257. We check for insufficient
1315 * lookahead only every 4th comparison; the 128th check will be made
1316 * at strstart+257. If MAX_MATCH-2 is not a multiple of 8, it is
1317 * necessary to put more guard bytes at the end of the window, or
1318 * to check more often for insufficient lookahead.
1322 } while (*(ush *) (scan += 2) == *(ush *) (match += 2) &&
1323 *(ush *) (scan += 2) == *(ush *) (match += 2) &&
1324 *(ush *) (scan += 2) == *(ush *) (match += 2) &&
1325 *(ush *) (scan += 2) == *(ush *) (match += 2) &&
1327 /* The funny "do {}" generates better code on most compilers */
1329 /* Here, scan <= window+strstart+257 */
1330 Assert(scan <= window + (unsigned) (window_size - 1), "wild scan");
1331 if (*scan == *match)
1334 len = (MAX_MATCH - 1) - (int) (strend - scan);
1335 scan = strend - (MAX_MATCH - 1);
1337 #else /* UNALIGNED_OK */
1339 if (match[best_len] != scan_end ||
1340 match[best_len - 1] != scan_end1 ||
1341 *match != *scan || *++match != scan[1])
1344 /* The check at best_len-1 can be removed because it will be made
1345 * again later. (This heuristic is not always a win.)
1346 * It is not necessary to compare scan[2] and match[2] since they
1347 * are always equal when the other bytes match, given that
1348 * the hash keys are equal and that HASH_BITS >= 8.
1352 /* We check for insufficient lookahead only every 8th comparison;
1353 * the 256th check will be made at strstart+258.
1356 } while (*++scan == *++match && *++scan == *++match &&
1357 *++scan == *++match && *++scan == *++match &&
1358 *++scan == *++match && *++scan == *++match &&
1359 *++scan == *++match && *++scan == *++match &&
1362 len = MAX_MATCH - (int) (strend - scan);
1363 scan = strend - MAX_MATCH;
1365 #endif /* UNALIGNED_OK */
1367 if (len > best_len) {
1368 match_start = cur_match;
1370 if (len >= nice_match)
1373 scan_end = *(ush *) (scan + best_len - 1);
1375 scan_end1 = scan[best_len - 1];
1376 scan_end = scan[best_len];
1379 } while ((cur_match = prev[cur_match & WMASK]) > limit
1380 && --chain_length != 0);
1387 /* ===========================================================================
1388 * Check that the match at match_start is indeed a match.
1390 local void check_match(start, match, length)
1394 /* check that the match is indeed a match */
1395 if (memcmp((char *) window + match,
1396 (char *) window + start, length) != EQUAL) {
1398 " start %d, match %d, length %d\n", start, match, length);
1399 errorMsg("invalid match");
1402 fprintf(stderr, "\\[%d,%d]", start - match, length);
1404 putc(window[start++], stderr);
1405 } while (--length != 0);
1409 # define check_match(start, match, length)
1412 /* ===========================================================================
1413 * Fill the window when the lookahead becomes insufficient.
1414 * Updates strstart and lookahead, and sets eofile if end of input file.
1415 * IN assertion: lookahead < MIN_LOOKAHEAD && strstart + lookahead > 0
1416 * OUT assertions: at least one byte has been read, or eofile is set;
1417 * file reads are performed for at least two bytes (required for the
1418 * translate_eol option).
1420 local void fill_window()
1422 register unsigned n, m;
1425 (unsigned) (window_size - (ulg) lookahead - (ulg) strstart);
1426 /* Amount of free space at the end of the window. */
1428 /* If the window is almost full and there is insufficient lookahead,
1429 * move the upper half to the lower one to make room in the upper half.
1431 if (more == (unsigned) EOF) {
1432 /* Very unlikely, but possible on 16 bit machine if strstart == 0
1433 * and lookahead == 1 (input done one byte at time)
1436 } else if (strstart >= WSIZE + MAX_DIST) {
1437 /* By the IN assertion, the window is not empty so we can't confuse
1438 * more == 0 with more == 64K on a 16 bit machine.
1440 Assert(window_size == (ulg) 2 * WSIZE, "no sliding with BIG_MEM");
1442 memcpy((char *) window, (char *) window + WSIZE, (unsigned) WSIZE);
1443 match_start -= WSIZE;
1444 strstart -= WSIZE; /* we now have strstart >= MAX_DIST: */
1446 block_start -= (long) WSIZE;
1448 for (n = 0; n < HASH_SIZE; n++) {
1450 head[n] = (Pos) (m >= WSIZE ? m - WSIZE : NIL);
1452 for (n = 0; n < WSIZE; n++) {
1454 prev[n] = (Pos) (m >= WSIZE ? m - WSIZE : NIL);
1455 /* If n is not on any hash chain, prev[n] is garbage but
1456 * its value will never be used.
1461 /* At this point, more >= 2 */
1463 n = read_buf((char *) window + strstart + lookahead, more);
1464 if (n == 0 || n == (unsigned) EOF) {
1472 /* ===========================================================================
1473 * Flush the current block, with given end-of-file flag.
1474 * IN assertion: strstart is set to the end of the current match.
1476 #define FLUSH_BLOCK(eof) \
1477 flush_block(block_start >= 0L ? (char*)&window[(unsigned)block_start] : \
1478 (char*)NULL, (long)strstart - block_start, (eof))
1480 /* ===========================================================================
1481 * Same as above, but achieves better compression. We use a lazy
1482 * evaluation for matches: a match is finally adopted only if there is
1483 * no better match at the next window position.
1487 IPos hash_head; /* head of hash chain */
1488 IPos prev_match; /* previous match */
1489 int flush; /* set if current block must be flushed */
1490 int match_available = 0; /* set if previous match exists */
1491 register unsigned match_length = MIN_MATCH - 1; /* length of best match */
1494 extern long isize; /* byte length of input file, for debug only */
1497 /* Process the input block. */
1498 while (lookahead != 0) {
1499 /* Insert the string window[strstart .. strstart+2] in the
1500 * dictionary, and set hash_head to the head of the hash chain:
1502 INSERT_STRING(strstart, hash_head);
1504 /* Find the longest match, discarding those <= prev_length.
1506 prev_length = match_length, prev_match = match_start;
1507 match_length = MIN_MATCH - 1;
1509 if (hash_head != NIL && prev_length < max_lazy_match &&
1510 strstart - hash_head <= MAX_DIST) {
1511 /* To simplify the code, we prevent matches with the string
1512 * of window index 0 (in particular we have to avoid a match
1513 * of the string with itself at the start of the input file).
1515 match_length = longest_match(hash_head);
1516 /* longest_match() sets match_start */
1517 if (match_length > lookahead)
1518 match_length = lookahead;
1520 /* Ignore a length 3 match if it is too distant: */
1521 if (match_length == MIN_MATCH
1522 && strstart - match_start > TOO_FAR) {
1523 /* If prev_match is also MIN_MATCH, match_start is garbage
1524 * but we will ignore the current match anyway.
1529 /* If there was a match at the previous step and the current
1530 * match is not better, output the previous match:
1532 if (prev_length >= MIN_MATCH && match_length <= prev_length) {
1534 check_match(strstart - 1, prev_match, prev_length);
1537 ct_tally(strstart - 1 - prev_match,
1538 prev_length - MIN_MATCH);
1540 /* Insert in hash table all strings up to the end of the match.
1541 * strstart-1 and strstart are already inserted.
1543 lookahead -= prev_length - 1;
1547 INSERT_STRING(strstart, hash_head);
1548 /* strstart never exceeds WSIZE-MAX_MATCH, so there are
1549 * always MIN_MATCH bytes ahead. If lookahead < MIN_MATCH
1550 * these bytes are garbage, but it does not matter since the
1551 * next lookahead bytes will always be emitted as literals.
1553 } while (--prev_length != 0);
1554 match_available = 0;
1555 match_length = MIN_MATCH - 1;
1558 FLUSH_BLOCK(0), block_start = strstart;
1560 } else if (match_available) {
1561 /* If there was no match at the previous position, output a
1562 * single literal. If there was a match but the current match
1563 * is longer, truncate the previous match to a single literal.
1565 Tracevv((stderr, "%c", window[strstart - 1]));
1566 if (ct_tally(0, window[strstart - 1])) {
1567 FLUSH_BLOCK(0), block_start = strstart;
1572 /* There is no previous match to compare with, wait for
1573 * the next step to decide.
1575 match_available = 1;
1579 Assert(strstart <= isize && lookahead <= isize, "a bit too far");
1581 /* Make sure that we always have enough lookahead, except
1582 * at the end of the input file. We need MAX_MATCH bytes
1583 * for the next match, plus MIN_MATCH bytes to insert the
1584 * string following the next match.
1586 while (lookahead < MIN_LOOKAHEAD && !eofile)
1589 if (match_available)
1590 ct_tally(0, window[strstart - 1]);
1592 return FLUSH_BLOCK(1); /* eof */
1595 /* gzip (GNU zip) -- compress files with zip algorithm and 'compress' interface
1596 * Copyright (C) 1992-1993 Jean-loup Gailly
1597 * The unzip code was written and put in the public domain by Mark Adler.
1598 * Portions of the lzw code are derived from the public domain 'compress'
1599 * written by Spencer Thomas, Joe Orost, James Woods, Jim McKie, Steve Davies,
1600 * Ken Turkowski, Dave Mack and Peter Jannesen.
1602 * See the license_msg below and the file COPYING for the software license.
1603 * See the file algorithm.doc for the compression algorithms and file formats.
1606 /* Compress files with zip algorithm and 'compress' interface.
1607 * See usage() and help() functions below for all options.
1609 * file.gz: compressed file with same mode, owner, and utimes
1610 * or stdout with -c option or if stdin used as input.
1611 * If the output file name had to be truncated, the original name is kept
1612 * in the compressed file.
1613 * On MSDOS, file.tmp -> file.tmz. On VMS, file.tmp -> file.tmp-gz.
1615 * Using gz on MSDOS would create too many file name conflicts. For
1616 * example, foo.txt -> foo.tgz (.tgz must be reserved as shorthand for
1617 * tar.gz). Similarly, foo.dir and foo.doc would both be mapped to foo.dgz.
1618 * I also considered 12345678.txt -> 12345txt.gz but this truncates the name
1619 * too heavily. There is no ideal solution given the MSDOS 8+3 limitation.
1621 * For the meaning of all compilation flags, see comments in Makefile.in.
1625 #include <sys/types.h>
1627 #include <sys/stat.h>
1633 # include <sys/time.h>
1642 #ifdef HAVE_UNISTD_H
1643 # include <unistd.h>
1646 #if defined(STDC_HEADERS) || !defined(NO_STDLIB_H)
1647 # include <stdlib.h>
1653 # include <dirent.h>
1654 typedef struct dirent dir_type;
1656 # define NLENGTH(dirent) ((int)strlen((dirent)->d_name))
1657 # define DIR_OPT "DIRENT"
1659 # define NLENGTH(dirent) ((dirent)->d_namlen)
1661 # include <sys/dir.h>
1662 typedef struct direct dir_type;
1664 # define DIR_OPT "SYSDIR"
1667 # include <sys/ndir.h>
1668 typedef struct direct dir_type;
1670 # define DIR_OPT "SYSNDIR"
1674 typedef struct direct dir_type;
1676 # define DIR_OPT "NDIR"
1679 # define DIR_OPT "NO_DIR"
1688 # define TIME_OPT "UTIME"
1690 # ifdef HAVE_SYS_UTIME_H
1691 # include <sys/utime.h>
1692 # define TIME_OPT "SYS_UTIME"
1699 # define TIME_OPT ""
1703 # define TIME_OPT "NO_UTIME"
1706 #if !defined(S_ISDIR) && defined(S_IFDIR)
1707 # define S_ISDIR(m) (((m) & S_IFMT) == S_IFDIR)
1709 #if !defined(S_ISREG) && defined(S_IFREG)
1710 # define S_ISREG(m) (((m) & S_IFMT) == S_IFREG)
1713 typedef RETSIGTYPE(*sig_type) (int);
1716 # define O_BINARY 0 /* creation mode for open() */
1720 /* Pure BSD system? */
1721 # include <sys/file.h>
1723 # define O_CREAT FCREAT
1726 # define O_EXCL FEXCL
1731 # define S_IRUSR 0400
1734 # define S_IWUSR 0200
1736 #define RW_USER (S_IRUSR | S_IWUSR) /* creation mode for open() */
1738 #ifndef MAX_PATH_LEN
1739 # define MAX_PATH_LEN 1024 /* max pathname length */
1748 off_t lseek (int fd, off_t offset, int whence);
1751 /* Separator for file name parts (see shorten_name()) */
1752 #ifdef NO_MULTIPLE_DOTS
1753 # define PART_SEP "-"
1755 # define PART_SEP "."
1758 /* global buffers */
1760 DECLARE(uch, inbuf, INBUFSIZ + INBUF_EXTRA);
1761 DECLARE(uch, outbuf, OUTBUFSIZ + OUTBUF_EXTRA);
1762 DECLARE(ush, d_buf, DIST_BUFSIZE);
1763 DECLARE(uch, window, 2L * WSIZE);
1765 DECLARE(ush, tab_prefix, 1L << BITS);
1767 DECLARE(ush, tab_prefix0, 1L << (BITS - 1));
1768 DECLARE(ush, tab_prefix1, 1L << (BITS - 1));
1771 /* local variables */
1773 int ascii = 0; /* convert end-of-lines to local OS conventions */
1774 int decompress = 0; /* decompress (-d) */
1775 int no_name = -1; /* don't save or restore the original file name */
1776 int no_time = -1; /* don't save or restore the original file time */
1777 int foreground; /* set if program run in foreground */
1778 char *progname; /* program name */
1779 static int method = DEFLATED; /* compression method */
1780 static int exit_code = OK; /* program exit code */
1781 int save_orig_name; /* set if original name must be saved */
1782 int last_member; /* set for .zip and .Z files */
1783 int part_nb; /* number of parts in .gz file */
1784 long time_stamp; /* original time stamp (modification time) */
1785 long ifile_size; /* input file size, -1 for devices (debug only) */
1786 char *env; /* contents of GZIP env variable */
1787 char z_suffix[MAX_SUFFIX + 1]; /* default suffix (can be set with --suffix) */
1788 int z_len; /* strlen(z_suffix) */
1790 long bytes_in; /* number of input bytes */
1791 long bytes_out; /* number of output bytes */
1792 char ifname[MAX_PATH_LEN]; /* input file name */
1793 char ofname[MAX_PATH_LEN]; /* output file name */
1794 int remove_ofname = 0; /* remove output file on error */
1795 struct stat istat; /* status for input file */
1796 int ifd; /* input file descriptor */
1797 int ofd; /* output file descriptor */
1798 unsigned insize; /* valid bytes in inbuf */
1799 unsigned inptr; /* index of next byte to be processed in inbuf */
1800 unsigned outcnt; /* bytes in output buffer */
1802 /* local functions */
1804 #define strequ(s1, s2) (strcmp((s1),(s2)) == 0)
1806 /* ======================================================================== */
1807 // int main (argc, argv)
1810 int gzip_main(int argc, char **argv)
1815 struct stat statBuf;
1823 /* Parse any options */
1824 while (--argc > 0 && **(++argv) == '-') {
1825 if (*((*argv) + 1) == '\0') {
1829 while (*(++(*argv))) {
1840 foreground = signal(SIGINT, SIG_IGN) != SIG_IGN;
1842 (void) signal(SIGINT, (sig_type) abort_gzip);
1845 if (signal(SIGTERM, SIG_IGN) != SIG_IGN) {
1846 (void) signal(SIGTERM, (sig_type) abort_gzip);
1850 if (signal(SIGHUP, SIG_IGN) != SIG_IGN) {
1851 (void) signal(SIGHUP, (sig_type) abort_gzip);
1855 strncpy(z_suffix, Z_SUFFIX, sizeof(z_suffix) - 1);
1856 z_len = strlen(z_suffix);
1858 /* Allocate all global buffers (for DYN_ALLOC option) */
1859 ALLOC(uch, inbuf, INBUFSIZ + INBUF_EXTRA);
1860 ALLOC(uch, outbuf, OUTBUFSIZ + OUTBUF_EXTRA);
1861 ALLOC(ush, d_buf, DIST_BUFSIZE);
1862 ALLOC(uch, window, 2L * WSIZE);
1864 ALLOC(ush, tab_prefix, 1L << BITS);
1866 ALLOC(ush, tab_prefix0, 1L << (BITS - 1));
1867 ALLOC(ush, tab_prefix1, 1L << (BITS - 1));
1870 if (fromstdin == 1) {
1871 strcpy(ofname, "stdin");
1873 inFileNum = fileno(stdin);
1874 time_stamp = 0; /* time unknown by default */
1875 ifile_size = -1L; /* convention for unknown size */
1877 /* Open up the input file */
1880 strncpy(ifname, *argv, MAX_PATH_LEN);
1882 /* Open input fille */
1883 inFileNum = open(ifname, O_RDONLY);
1884 if (inFileNum < 0) {
1888 /* Get the time stamp on the input file. */
1889 result = stat(ifname, &statBuf);
1894 time_stamp = statBuf.st_ctime;
1895 ifile_size = statBuf.st_size;
1899 if (tostdout == 1) {
1900 /* And get to work */
1901 strcpy(ofname, "stdout");
1902 outFileNum = fileno(stdout);
1903 SET_BINARY_MODE(fileno(stdout));
1905 clear_bufs(); /* clear input and output buffers */
1908 /* Actually do the compression/decompression. */
1909 zip(inFileNum, outFileNum);
1913 /* And get to work */
1914 strncpy(ofname, ifname, MAX_PATH_LEN - 4);
1915 strcat(ofname, ".gz");
1918 /* Open output fille */
1919 #if (__GLIBC__ >= 2) && (__GLIBC_MINOR__ >= 1)
1920 outFileNum = open(ofname, O_RDWR | O_CREAT | O_EXCL | O_NOFOLLOW);
1922 outFileNum = open(ofname, O_RDWR | O_CREAT | O_EXCL);
1924 if (outFileNum < 0) {
1928 SET_BINARY_MODE(outFileNum);
1929 /* Set permissions on the file */
1930 fchmod(outFileNum, statBuf.st_mode);
1932 clear_bufs(); /* clear input and output buffers */
1935 /* Actually do the compression/decompression. */
1936 result = zip(inFileNum, outFileNum);
1939 /* Delete the original file */
1941 delFileName = ifname;
1943 delFileName = ofname;
1945 if (unlink(delFileName) < 0) {
1946 perror(delFileName);
1954 /* trees.c -- output deflated data using Huffman coding
1955 * Copyright (C) 1992-1993 Jean-loup Gailly
1956 * This is free software; you can redistribute it and/or modify it under the
1957 * terms of the GNU General Public License, see the file COPYING.
1963 * Encode various sets of source values using variable-length
1964 * binary code trees.
1968 * The PKZIP "deflation" process uses several Huffman trees. The more
1969 * common source values are represented by shorter bit sequences.
1971 * Each code tree is stored in the ZIP file in a compressed form
1972 * which is itself a Huffman encoding of the lengths of
1973 * all the code strings (in ascending order by source values).
1974 * The actual code strings are reconstructed from the lengths in
1975 * the UNZIP process, as described in the "application note"
1976 * (APPNOTE.TXT) distributed as part of PKWARE's PKZIP program.
1981 * Data Compression: Techniques and Applications, pp. 53-55.
1982 * Lifetime Learning Publications, 1985. ISBN 0-534-03418-7.
1985 * Data Compression: Methods and Theory, pp. 49-50.
1986 * Computer Science Press, 1988. ISBN 0-7167-8156-5.
1990 * Addison-Wesley, 1983. ISBN 0-201-06672-6.
1994 * void ct_init (ush *attr, int *methodp)
1995 * Allocate the match buffer, initialize the various tables and save
1996 * the location of the internal file attribute (ascii/binary) and
1997 * method (DEFLATE/STORE)
1999 * void ct_tally (int dist, int lc);
2000 * Save the match info and tally the frequency counts.
2002 * long flush_block (char *buf, ulg stored_len, int eof)
2003 * Determine the best encoding for the current block: dynamic trees,
2004 * static trees or store, and output the encoded block to the zip
2005 * file. Returns the total compressed length for the file so far.
2011 /* ===========================================================================
2016 /* All codes must not exceed MAX_BITS bits */
2018 #define MAX_BL_BITS 7
2019 /* Bit length codes must not exceed MAX_BL_BITS bits */
2021 #define LENGTH_CODES 29
2022 /* number of length codes, not counting the special END_BLOCK code */
2024 #define LITERALS 256
2025 /* number of literal bytes 0..255 */
2027 #define END_BLOCK 256
2028 /* end of block literal code */
2030 #define L_CODES (LITERALS+1+LENGTH_CODES)
2031 /* number of Literal or Length codes, including the END_BLOCK code */
2034 /* number of distance codes */
2037 /* number of codes used to transfer the bit lengths */
2040 local int near extra_lbits[LENGTH_CODES] /* extra bits for each length code */
2041 = { 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4,
2042 4, 4, 5, 5, 5, 5, 0 };
2044 local int near extra_dbits[D_CODES] /* extra bits for each distance code */
2045 = { 0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6, 7, 7, 8, 8, 9, 9,
2046 10, 10, 11, 11, 12, 12, 13, 13 };
2048 local int near extra_blbits[BL_CODES] /* extra bits for each bit length code */
2049 = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 3, 7 };
2051 #define STORED_BLOCK 0
2052 #define STATIC_TREES 1
2054 /* The three kinds of block type */
2058 # define LIT_BUFSIZE 0x2000
2061 # define LIT_BUFSIZE 0x4000
2063 # define LIT_BUFSIZE 0x8000
2067 #ifndef DIST_BUFSIZE
2068 # define DIST_BUFSIZE LIT_BUFSIZE
2070 /* Sizes of match buffers for literals/lengths and distances. There are
2071 * 4 reasons for limiting LIT_BUFSIZE to 64K:
2072 * - frequencies can be kept in 16 bit counters
2073 * - if compression is not successful for the first block, all input data is
2074 * still in the window so we can still emit a stored block even when input
2075 * comes from standard input. (This can also be done for all blocks if
2076 * LIT_BUFSIZE is not greater than 32K.)
2077 * - if compression is not successful for a file smaller than 64K, we can
2078 * even emit a stored file instead of a stored block (saving 5 bytes).
2079 * - creating new Huffman trees less frequently may not provide fast
2080 * adaptation to changes in the input data statistics. (Take for
2081 * example a binary file with poorly compressible code followed by
2082 * a highly compressible string table.) Smaller buffer sizes give
2083 * fast adaptation but have of course the overhead of transmitting trees
2085 * - I can't count above 4
2086 * The current code is general and allows DIST_BUFSIZE < LIT_BUFSIZE (to save
2087 * memory at the expense of compression). Some optimizations would be possible
2088 * if we rely on DIST_BUFSIZE == LIT_BUFSIZE.
2090 #if LIT_BUFSIZE > INBUFSIZ
2091 error cannot overlay l_buf and inbuf
2094 /* repeat previous bit length 3-6 times (2 bits of repeat count) */
2095 #define REPZ_3_10 17
2096 /* repeat a zero length 3-10 times (3 bits of repeat count) */
2097 #define REPZ_11_138 18
2098 /* repeat a zero length 11-138 times (7 bits of repeat count) *//* ===========================================================================
2100 *//* Data structure describing a single value and its code string. */ typedef struct ct_data {
2102 ush freq; /* frequency count */
2103 ush code; /* bit string */
2106 ush dad; /* father node in Huffman tree */
2107 ush len; /* length of bit string */
2111 #define Freq fc.freq
2112 #define Code fc.code
2116 #define HEAP_SIZE (2*L_CODES+1)
2117 /* maximum heap size */
2119 local ct_data near dyn_ltree[HEAP_SIZE]; /* literal and length tree */
2120 local ct_data near dyn_dtree[2 * D_CODES + 1]; /* distance tree */
2122 local ct_data near static_ltree[L_CODES + 2];
2124 /* The static literal tree. Since the bit lengths are imposed, there is no
2125 * need for the L_CODES extra codes used during heap construction. However
2126 * The codes 286 and 287 are needed to build a canonical tree (see ct_init
2130 local ct_data near static_dtree[D_CODES];
2132 /* The static distance tree. (Actually a trivial tree since all codes use
2136 local ct_data near bl_tree[2 * BL_CODES + 1];
2138 /* Huffman tree for the bit lengths */
2140 typedef struct tree_desc {
2141 ct_data near *dyn_tree; /* the dynamic tree */
2142 ct_data near *static_tree; /* corresponding static tree or NULL */
2143 int near *extra_bits; /* extra bits for each code or NULL */
2144 int extra_base; /* base index for extra_bits */
2145 int elems; /* max number of elements in the tree */
2146 int max_length; /* max bit length for the codes */
2147 int max_code; /* largest code with non zero frequency */
2150 local tree_desc near l_desc =
2151 { dyn_ltree, static_ltree, extra_lbits, LITERALS + 1, L_CODES,
2154 local tree_desc near d_desc =
2155 { dyn_dtree, static_dtree, extra_dbits, 0, D_CODES, MAX_BITS, 0 };
2157 local tree_desc near bl_desc =
2158 { bl_tree, (ct_data near *) 0, extra_blbits, 0, BL_CODES, MAX_BL_BITS,
2162 local ush near bl_count[MAX_BITS + 1];
2164 /* number of codes at each bit length for an optimal tree */
2166 local uch near bl_order[BL_CODES]
2167 = { 16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15 };
2169 /* The lengths of the bit length codes are sent in order of decreasing
2170 * probability, to avoid transmitting the lengths for unused bit length codes.
2173 local int near heap[2 * L_CODES + 1]; /* heap used to build the Huffman trees */
2174 local int heap_len; /* number of elements in the heap */
2175 local int heap_max; /* element of largest frequency */
2177 /* The sons of heap[n] are heap[2*n] and heap[2*n+1]. heap[0] is not used.
2178 * The same heap array is used to build all trees.
2181 local uch near depth[2 * L_CODES + 1];
2183 /* Depth of each subtree used as tie breaker for trees of equal frequency */
2185 local uch length_code[MAX_MATCH - MIN_MATCH + 1];
2187 /* length code for each normalized match length (0 == MIN_MATCH) */
2189 local uch dist_code[512];
2191 /* distance codes. The first 256 values correspond to the distances
2192 * 3 .. 258, the last 256 values correspond to the top 8 bits of
2193 * the 15 bit distances.
2196 local int near base_length[LENGTH_CODES];
2198 /* First normalized length for each code (0 = MIN_MATCH) */
2200 local int near base_dist[D_CODES];
2202 /* First normalized distance for each code (0 = distance of 1) */
2205 /* DECLARE(uch, l_buf, LIT_BUFSIZE); buffer for literals or lengths */
2207 /* DECLARE(ush, d_buf, DIST_BUFSIZE); buffer for distances */
2209 local uch near flag_buf[(LIT_BUFSIZE / 8)];
2211 /* flag_buf is a bit array distinguishing literals from lengths in
2212 * l_buf, thus indicating the presence or absence of a distance.
2215 local unsigned last_lit; /* running index in l_buf */
2216 local unsigned last_dist; /* running index in d_buf */
2217 local unsigned last_flags; /* running index in flag_buf */
2218 local uch flags; /* current flags not yet saved in flag_buf */
2219 local uch flag_bit; /* current bit used in flags */
2221 /* bits are filled in flags starting at bit 0 (least significant).
2222 * Note: these flags are overkill in the current code since we don't
2223 * take advantage of DIST_BUFSIZE == LIT_BUFSIZE.
2226 local ulg opt_len; /* bit length of current block with optimal trees */
2227 local ulg static_len; /* bit length of current block with static trees */
2229 local ulg compressed_len; /* total bit length of compressed file */
2231 local ulg input_len; /* total byte length of input file */
2233 /* input_len is for debugging only since we can get it by other means. */
2235 ush *file_type; /* pointer to UNKNOWN, BINARY or ASCII */
2236 int *file_method; /* pointer to DEFLATE or STORE */
2239 extern ulg bits_sent; /* bit length of the compressed data */
2240 extern long isize; /* byte length of input file */
2243 extern long block_start; /* window offset of current block */
2244 extern unsigned near strstart; /* window offset of current string */
2246 /* ===========================================================================
2247 * Local (static) routines in this file.
2250 local void init_block (void);
2251 local void pqdownheap (ct_data near * tree, int k);
2252 local void gen_bitlen (tree_desc near * desc);
2253 local void gen_codes (ct_data near * tree, int max_code);
2254 local void build_tree (tree_desc near * desc);
2255 local void scan_tree (ct_data near * tree, int max_code);
2256 local void send_tree (ct_data near * tree, int max_code);
2257 local int build_bl_tree (void);
2258 local void send_all_trees (int lcodes, int dcodes, int blcodes);
2259 local void compress_block (ct_data near * ltree, ct_data near * dtree);
2260 local void set_file_type (void);
2264 # define send_code(c, tree) send_bits(tree[c].Code, tree[c].Len)
2265 /* Send a code of the given tree. c and tree must not have side effects */
2268 # define send_code(c, tree) \
2269 { if (verbose>1) fprintf(stderr,"\ncd %3d ",(c)); \
2270 send_bits(tree[c].Code, tree[c].Len); }
2273 #define d_code(dist) \
2274 ((dist) < 256 ? dist_code[dist] : dist_code[256+((dist)>>7)])
2275 /* Mapping from a distance to a distance code. dist is the distance - 1 and
2276 * must not have side effects. dist_code[256] and dist_code[257] are never
2280 /* the arguments must not have side effects */
2282 /* ===========================================================================
2283 * Allocate the match buffer, initialize the various tables and save the
2284 * location of the internal file attribute (ascii/binary) and method
2287 void ct_init(attr, methodp)
2288 ush *attr; /* pointer to internal file attribute */
2289 int *methodp; /* pointer to compression method */
2291 int n; /* iterates over tree elements */
2292 int bits; /* bit counter */
2293 int length; /* length value */
2294 int code; /* code value */
2295 int dist; /* distance index */
2298 file_method = methodp;
2299 compressed_len = input_len = 0L;
2301 if (static_dtree[0].Len != 0)
2302 return; /* ct_init already called */
2304 /* Initialize the mapping length (0..255) -> length code (0..28) */
2306 for (code = 0; code < LENGTH_CODES - 1; code++) {
2307 base_length[code] = length;
2308 for (n = 0; n < (1 << extra_lbits[code]); n++) {
2309 length_code[length++] = (uch) code;
2312 Assert(length == 256, "ct_init: length != 256");
2313 /* Note that the length 255 (match length 258) can be represented
2314 * in two different ways: code 284 + 5 bits or code 285, so we
2315 * overwrite length_code[255] to use the best encoding:
2317 length_code[length - 1] = (uch) code;
2319 /* Initialize the mapping dist (0..32K) -> dist code (0..29) */
2321 for (code = 0; code < 16; code++) {
2322 base_dist[code] = dist;
2323 for (n = 0; n < (1 << extra_dbits[code]); n++) {
2324 dist_code[dist++] = (uch) code;
2327 Assert(dist == 256, "ct_init: dist != 256");
2328 dist >>= 7; /* from now on, all distances are divided by 128 */
2329 for (; code < D_CODES; code++) {
2330 base_dist[code] = dist << 7;
2331 for (n = 0; n < (1 << (extra_dbits[code] - 7)); n++) {
2332 dist_code[256 + dist++] = (uch) code;
2335 Assert(dist == 256, "ct_init: 256+dist != 512");
2337 /* Construct the codes of the static literal tree */
2338 for (bits = 0; bits <= MAX_BITS; bits++)
2342 static_ltree[n++].Len = 8, bl_count[8]++;
2344 static_ltree[n++].Len = 9, bl_count[9]++;
2346 static_ltree[n++].Len = 7, bl_count[7]++;
2348 static_ltree[n++].Len = 8, bl_count[8]++;
2349 /* Codes 286 and 287 do not exist, but we must include them in the
2350 * tree construction to get a canonical Huffman tree (longest code
2353 gen_codes((ct_data near *) static_ltree, L_CODES + 1);
2355 /* The static distance tree is trivial: */
2356 for (n = 0; n < D_CODES; n++) {
2357 static_dtree[n].Len = 5;
2358 static_dtree[n].Code = bi_reverse(n, 5);
2361 /* Initialize the first block of the first file: */
2365 /* ===========================================================================
2366 * Initialize a new block.
2368 local void init_block()
2370 int n; /* iterates over tree elements */
2372 /* Initialize the trees. */
2373 for (n = 0; n < L_CODES; n++)
2374 dyn_ltree[n].Freq = 0;
2375 for (n = 0; n < D_CODES; n++)
2376 dyn_dtree[n].Freq = 0;
2377 for (n = 0; n < BL_CODES; n++)
2378 bl_tree[n].Freq = 0;
2380 dyn_ltree[END_BLOCK].Freq = 1;
2381 opt_len = static_len = 0L;
2382 last_lit = last_dist = last_flags = 0;
2388 /* Index within the heap array of least frequent node in the Huffman tree */
2391 /* ===========================================================================
2392 * Remove the smallest element from the heap and recreate the heap with
2393 * one less element. Updates heap and heap_len.
2395 #define pqremove(tree, top) \
2397 top = heap[SMALLEST]; \
2398 heap[SMALLEST] = heap[heap_len--]; \
2399 pqdownheap(tree, SMALLEST); \
2402 /* ===========================================================================
2403 * Compares to subtrees, using the tree depth as tie breaker when
2404 * the subtrees have equal frequency. This minimizes the worst case length.
2406 #define smaller(tree, n, m) \
2407 (tree[n].Freq < tree[m].Freq || \
2408 (tree[n].Freq == tree[m].Freq && depth[n] <= depth[m]))
2410 /* ===========================================================================
2411 * Restore the heap property by moving down the tree starting at node k,
2412 * exchanging a node with the smallest of its two sons if necessary, stopping
2413 * when the heap property is re-established (each father smaller than its
2416 local void pqdownheap(tree, k)
2417 ct_data near *tree; /* the tree to restore */
2418 int k; /* node to move down */
2421 int j = k << 1; /* left son of k */
2423 while (j <= heap_len) {
2424 /* Set j to the smallest of the two sons: */
2425 if (j < heap_len && smaller(tree, heap[j + 1], heap[j]))
2428 /* Exit if v is smaller than both sons */
2429 if (smaller(tree, v, heap[j]))
2432 /* Exchange v with the smallest son */
2436 /* And continue down the tree, setting j to the left son of k */
2442 /* ===========================================================================
2443 * Compute the optimal bit lengths for a tree and update the total bit length
2444 * for the current block.
2445 * IN assertion: the fields freq and dad are set, heap[heap_max] and
2446 * above are the tree nodes sorted by increasing frequency.
2447 * OUT assertions: the field len is set to the optimal bit length, the
2448 * array bl_count contains the frequencies for each bit length.
2449 * The length opt_len is updated; static_len is also updated if stree is
2452 local void gen_bitlen(desc)
2453 tree_desc near *desc; /* the tree descriptor */
2455 ct_data near *tree = desc->dyn_tree;
2456 int near *extra = desc->extra_bits;
2457 int base = desc->extra_base;
2458 int max_code = desc->max_code;
2459 int max_length = desc->max_length;
2460 ct_data near *stree = desc->static_tree;
2461 int h; /* heap index */
2462 int n, m; /* iterate over the tree elements */
2463 int bits; /* bit length */
2464 int xbits; /* extra bits */
2465 ush f; /* frequency */
2466 int overflow = 0; /* number of elements with bit length too large */
2468 for (bits = 0; bits <= MAX_BITS; bits++)
2471 /* In a first pass, compute the optimal bit lengths (which may
2472 * overflow in the case of the bit length tree).
2474 tree[heap[heap_max]].Len = 0; /* root of the heap */
2476 for (h = heap_max + 1; h < HEAP_SIZE; h++) {
2478 bits = tree[tree[n].Dad].Len + 1;
2479 if (bits > max_length)
2480 bits = max_length, overflow++;
2481 tree[n].Len = (ush) bits;
2482 /* We overwrite tree[n].Dad which is no longer needed */
2485 continue; /* not a leaf node */
2490 xbits = extra[n - base];
2492 opt_len += (ulg) f *(bits + xbits);
2495 static_len += (ulg) f *(stree[n].Len + xbits);
2500 Trace((stderr, "\nbit length overflow\n"));
2501 /* This happens for example on obj2 and pic of the Calgary corpus */
2503 /* Find the first bit length which could increase: */
2505 bits = max_length - 1;
2506 while (bl_count[bits] == 0)
2508 bl_count[bits]--; /* move one leaf down the tree */
2509 bl_count[bits + 1] += 2; /* move one overflow item as its brother */
2510 bl_count[max_length]--;
2511 /* The brother of the overflow item also moves one step up,
2512 * but this does not affect bl_count[max_length]
2515 } while (overflow > 0);
2517 /* Now recompute all bit lengths, scanning in increasing frequency.
2518 * h is still equal to HEAP_SIZE. (It is simpler to reconstruct all
2519 * lengths instead of fixing only the wrong ones. This idea is taken
2520 * from 'ar' written by Haruhiko Okumura.)
2522 for (bits = max_length; bits != 0; bits--) {
2528 if (tree[m].Len != (unsigned) bits) {
2530 (stderr, "code %d bits %d->%d\n", m, tree[m].Len,
2534 (long) tree[m].Len) * (long) tree[m].Freq;
2535 tree[m].Len = (ush) bits;
2542 /* ===========================================================================
2543 * Generate the codes for a given tree and bit counts (which need not be
2545 * IN assertion: the array bl_count contains the bit length statistics for
2546 * the given tree and the field len is set for all tree elements.
2547 * OUT assertion: the field code is set for all tree elements of non
2550 local void gen_codes(tree, max_code)
2551 ct_data near *tree; /* the tree to decorate */
2552 int max_code; /* largest code with non zero frequency */
2554 ush next_code[MAX_BITS + 1]; /* next code value for each bit length */
2555 ush code = 0; /* running code value */
2556 int bits; /* bit index */
2557 int n; /* code index */
2559 /* The distribution counts are first used to generate the code values
2560 * without bit reversal.
2562 for (bits = 1; bits <= MAX_BITS; bits++) {
2563 next_code[bits] = code = (code + bl_count[bits - 1]) << 1;
2565 /* Check that the bit counts in bl_count are consistent. The last code
2568 Assert(code + bl_count[MAX_BITS] - 1 == (1 << MAX_BITS) - 1,
2569 "inconsistent bit counts");
2570 Tracev((stderr, "\ngen_codes: max_code %d ", max_code));
2572 for (n = 0; n <= max_code; n++) {
2573 int len = tree[n].Len;
2577 /* Now reverse the bits */
2578 tree[n].Code = bi_reverse(next_code[len]++, len);
2580 Tracec(tree != static_ltree,
2581 (stderr, "\nn %3d %c l %2d c %4x (%x) ", n,
2582 (isgraph(n) ? n : ' '), len, tree[n].Code,
2583 next_code[len] - 1));
2587 /* ===========================================================================
2588 * Construct one Huffman tree and assigns the code bit strings and lengths.
2589 * Update the total bit length for the current block.
2590 * IN assertion: the field freq is set for all tree elements.
2591 * OUT assertions: the fields len and code are set to the optimal bit length
2592 * and corresponding code. The length opt_len is updated; static_len is
2593 * also updated if stree is not null. The field max_code is set.
2595 local void build_tree(desc)
2596 tree_desc near *desc; /* the tree descriptor */
2598 ct_data near *tree = desc->dyn_tree;
2599 ct_data near *stree = desc->static_tree;
2600 int elems = desc->elems;
2601 int n, m; /* iterate over heap elements */
2602 int max_code = -1; /* largest code with non zero frequency */
2603 int node = elems; /* next internal node of the tree */
2605 /* Construct the initial heap, with least frequent element in
2606 * heap[SMALLEST]. The sons of heap[n] are heap[2*n] and heap[2*n+1].
2607 * heap[0] is not used.
2609 heap_len = 0, heap_max = HEAP_SIZE;
2611 for (n = 0; n < elems; n++) {
2612 if (tree[n].Freq != 0) {
2613 heap[++heap_len] = max_code = n;
2620 /* The pkzip format requires that at least one distance code exists,
2621 * and that at least one bit should be sent even if there is only one
2622 * possible code. So to avoid special checks later on we force at least
2623 * two codes of non zero frequency.
2625 while (heap_len < 2) {
2626 int new = heap[++heap_len] = (max_code < 2 ? ++max_code : 0);
2632 static_len -= stree[new].Len;
2633 /* new is 0 or 1 so it does not have extra bits */
2635 desc->max_code = max_code;
2637 /* The elements heap[heap_len/2+1 .. heap_len] are leaves of the tree,
2638 * establish sub-heaps of increasing lengths:
2640 for (n = heap_len / 2; n >= 1; n--)
2641 pqdownheap(tree, n);
2643 /* Construct the Huffman tree by repeatedly combining the least two
2647 pqremove(tree, n); /* n = node of least frequency */
2648 m = heap[SMALLEST]; /* m = node of next least frequency */
2650 heap[--heap_max] = n; /* keep the nodes sorted by frequency */
2651 heap[--heap_max] = m;
2653 /* Create a new node father of n and m */
2654 tree[node].Freq = tree[n].Freq + tree[m].Freq;
2655 depth[node] = (uch) (MAX(depth[n], depth[m]) + 1);
2656 tree[n].Dad = tree[m].Dad = (ush) node;
2658 if (tree == bl_tree) {
2659 fprintf(stderr, "\nnode %d(%d), sons %d(%d) %d(%d)",
2660 node, tree[node].Freq, n, tree[n].Freq, m,
2664 /* and insert the new node in the heap */
2665 heap[SMALLEST] = node++;
2666 pqdownheap(tree, SMALLEST);
2668 } while (heap_len >= 2);
2670 heap[--heap_max] = heap[SMALLEST];
2672 /* At this point, the fields freq and dad are set. We can now
2673 * generate the bit lengths.
2675 gen_bitlen((tree_desc near *) desc);
2677 /* The field len is now set, we can generate the bit codes */
2678 gen_codes((ct_data near *) tree, max_code);
2681 /* ===========================================================================
2682 * Scan a literal or distance tree to determine the frequencies of the codes
2683 * in the bit length tree. Updates opt_len to take into account the repeat
2684 * counts. (The contribution of the bit length codes will be added later
2685 * during the construction of bl_tree.)
2687 local void scan_tree(tree, max_code)
2688 ct_data near *tree; /* the tree to be scanned */
2689 int max_code; /* and its largest code of non zero frequency */
2691 int n; /* iterates over all tree elements */
2692 int prevlen = -1; /* last emitted length */
2693 int curlen; /* length of current code */
2694 int nextlen = tree[0].Len; /* length of next code */
2695 int count = 0; /* repeat count of the current code */
2696 int max_count = 7; /* max repeat count */
2697 int min_count = 4; /* min repeat count */
2700 max_count = 138, min_count = 3;
2701 tree[max_code + 1].Len = (ush) 0xffff; /* guard */
2703 for (n = 0; n <= max_code; n++) {
2705 nextlen = tree[n + 1].Len;
2706 if (++count < max_count && curlen == nextlen) {
2708 } else if (count < min_count) {
2709 bl_tree[curlen].Freq += count;
2710 } else if (curlen != 0) {
2711 if (curlen != prevlen)
2712 bl_tree[curlen].Freq++;
2713 bl_tree[REP_3_6].Freq++;
2714 } else if (count <= 10) {
2715 bl_tree[REPZ_3_10].Freq++;
2717 bl_tree[REPZ_11_138].Freq++;
2722 max_count = 138, min_count = 3;
2723 } else if (curlen == nextlen) {
2724 max_count = 6, min_count = 3;
2726 max_count = 7, min_count = 4;
2731 /* ===========================================================================
2732 * Send a literal or distance tree in compressed form, using the codes in
2735 local void send_tree(tree, max_code)
2736 ct_data near *tree; /* the tree to be scanned */
2737 int max_code; /* and its largest code of non zero frequency */
2739 int n; /* iterates over all tree elements */
2740 int prevlen = -1; /* last emitted length */
2741 int curlen; /* length of current code */
2742 int nextlen = tree[0].Len; /* length of next code */
2743 int count = 0; /* repeat count of the current code */
2744 int max_count = 7; /* max repeat count */
2745 int min_count = 4; /* min repeat count */
2747 /* tree[max_code+1].Len = -1; *//* guard already set */
2749 max_count = 138, min_count = 3;
2751 for (n = 0; n <= max_code; n++) {
2753 nextlen = tree[n + 1].Len;
2754 if (++count < max_count && curlen == nextlen) {
2756 } else if (count < min_count) {
2758 send_code(curlen, bl_tree);
2759 } while (--count != 0);
2761 } else if (curlen != 0) {
2762 if (curlen != prevlen) {
2763 send_code(curlen, bl_tree);
2766 Assert(count >= 3 && count <= 6, " 3_6?");
2767 send_code(REP_3_6, bl_tree);
2768 send_bits(count - 3, 2);
2770 } else if (count <= 10) {
2771 send_code(REPZ_3_10, bl_tree);
2772 send_bits(count - 3, 3);
2775 send_code(REPZ_11_138, bl_tree);
2776 send_bits(count - 11, 7);
2781 max_count = 138, min_count = 3;
2782 } else if (curlen == nextlen) {
2783 max_count = 6, min_count = 3;
2785 max_count = 7, min_count = 4;
2790 /* ===========================================================================
2791 * Construct the Huffman tree for the bit lengths and return the index in
2792 * bl_order of the last bit length code to send.
2794 local int build_bl_tree()
2796 int max_blindex; /* index of last bit length code of non zero freq */
2798 /* Determine the bit length frequencies for literal and distance trees */
2799 scan_tree((ct_data near *) dyn_ltree, l_desc.max_code);
2800 scan_tree((ct_data near *) dyn_dtree, d_desc.max_code);
2802 /* Build the bit length tree: */
2803 build_tree((tree_desc near *) (&bl_desc));
2804 /* opt_len now includes the length of the tree representations, except
2805 * the lengths of the bit lengths codes and the 5+5+4 bits for the counts.
2808 /* Determine the number of bit length codes to send. The pkzip format
2809 * requires that at least 4 bit length codes be sent. (appnote.txt says
2810 * 3 but the actual value used is 4.)
2812 for (max_blindex = BL_CODES - 1; max_blindex >= 3; max_blindex--) {
2813 if (bl_tree[bl_order[max_blindex]].Len != 0)
2816 /* Update opt_len to include the bit length tree and counts */
2817 opt_len += 3 * (max_blindex + 1) + 5 + 5 + 4;
2819 (stderr, "\ndyn trees: dyn %ld, stat %ld", opt_len,
2825 /* ===========================================================================
2826 * Send the header for a block using dynamic Huffman trees: the counts, the
2827 * lengths of the bit length codes, the literal tree and the distance tree.
2828 * IN assertion: lcodes >= 257, dcodes >= 1, blcodes >= 4.
2830 local void send_all_trees(lcodes, dcodes, blcodes)
2831 int lcodes, dcodes, blcodes; /* number of codes for each tree */
2833 int rank; /* index in bl_order */
2835 Assert(lcodes >= 257 && dcodes >= 1
2836 && blcodes >= 4, "not enough codes");
2837 Assert(lcodes <= L_CODES && dcodes <= D_CODES
2838 && blcodes <= BL_CODES, "too many codes");
2839 Tracev((stderr, "\nbl counts: "));
2840 send_bits(lcodes - 257, 5); /* not +255 as stated in appnote.txt */
2841 send_bits(dcodes - 1, 5);
2842 send_bits(blcodes - 4, 4); /* not -3 as stated in appnote.txt */
2843 for (rank = 0; rank < blcodes; rank++) {
2844 Tracev((stderr, "\nbl code %2d ", bl_order[rank]));
2845 send_bits(bl_tree[bl_order[rank]].Len, 3);
2847 Tracev((stderr, "\nbl tree: sent %ld", bits_sent));
2849 send_tree((ct_data near *) dyn_ltree, lcodes - 1); /* send the literal tree */
2850 Tracev((stderr, "\nlit tree: sent %ld", bits_sent));
2852 send_tree((ct_data near *) dyn_dtree, dcodes - 1); /* send the distance tree */
2853 Tracev((stderr, "\ndist tree: sent %ld", bits_sent));
2856 /* ===========================================================================
2857 * Determine the best encoding for the current block: dynamic trees, static
2858 * trees or store, and output the encoded block to the zip file. This function
2859 * returns the total compressed length for the file so far.
2861 ulg flush_block(buf, stored_len, eof)
2862 char *buf; /* input block, or NULL if too old */
2863 ulg stored_len; /* length of input block */
2864 int eof; /* true if this is the last block for a file */
2866 ulg opt_lenb, static_lenb; /* opt_len and static_len in bytes */
2867 int max_blindex; /* index of last bit length code of non zero freq */
2869 flag_buf[last_flags] = flags; /* Save the flags for the last 8 items */
2871 /* Check if the file is ascii or binary */
2872 if (*file_type == (ush) UNKNOWN)
2875 /* Construct the literal and distance trees */
2876 build_tree((tree_desc near *) (&l_desc));
2877 Tracev((stderr, "\nlit data: dyn %ld, stat %ld", opt_len, static_len));
2879 build_tree((tree_desc near *) (&d_desc));
2881 (stderr, "\ndist data: dyn %ld, stat %ld", opt_len,
2883 /* At this point, opt_len and static_len are the total bit lengths of
2884 * the compressed block data, excluding the tree representations.
2887 /* Build the bit length tree for the above two trees, and get the index
2888 * in bl_order of the last bit length code to send.
2890 max_blindex = build_bl_tree();
2892 /* Determine the best encoding. Compute first the block length in bytes */
2893 opt_lenb = (opt_len + 3 + 7) >> 3;
2894 static_lenb = (static_len + 3 + 7) >> 3;
2895 input_len += stored_len; /* for debugging only */
2899 "\nopt %lu(%lu) stat %lu(%lu) stored %lu lit %u dist %u ",
2900 opt_lenb, opt_len, static_lenb, static_len, stored_len,
2901 last_lit, last_dist));
2903 if (static_lenb <= opt_lenb)
2904 opt_lenb = static_lenb;
2906 /* If compression failed and this is the first and last block,
2907 * and if the zip file can be seeked (to rewrite the local header),
2908 * the whole file is transformed into a stored file:
2912 if (stored_len <= opt_lenb && eof && compressed_len == 0L
2915 /* Since LIT_BUFSIZE <= 2*WSIZE, the input data must be there: */
2916 if (buf == (char *) 0)
2917 errorMsg("block vanished");
2919 copy_block(buf, (unsigned) stored_len, 0); /* without header */
2920 compressed_len = stored_len << 3;
2921 *file_method = STORED;
2925 } else if (stored_len + 4 <= opt_lenb && buf != (char *) 0) {
2926 /* 4: two words for the lengths */
2928 /* The test buf != NULL is only necessary if LIT_BUFSIZE > WSIZE.
2929 * Otherwise we can't have processed more than WSIZE input bytes since
2930 * the last block flush, because compression would have been
2931 * successful. If LIT_BUFSIZE <= WSIZE, it is never too late to
2932 * transform a block into a stored block.
2934 send_bits((STORED_BLOCK << 1) + eof, 3); /* send block type */
2935 compressed_len = (compressed_len + 3 + 7) & ~7L;
2936 compressed_len += (stored_len + 4) << 3;
2938 copy_block(buf, (unsigned) stored_len, 1); /* with header */
2942 } else if (static_lenb == opt_lenb) {
2944 send_bits((STATIC_TREES << 1) + eof, 3);
2945 compress_block((ct_data near *) static_ltree,
2946 (ct_data near *) static_dtree);
2947 compressed_len += 3 + static_len;
2949 send_bits((DYN_TREES << 1) + eof, 3);
2950 send_all_trees(l_desc.max_code + 1, d_desc.max_code + 1,
2952 compress_block((ct_data near *) dyn_ltree,
2953 (ct_data near *) dyn_dtree);
2954 compressed_len += 3 + opt_len;
2956 Assert(compressed_len == bits_sent, "bad compressed size");
2960 Assert(input_len == isize, "bad input size");
2962 compressed_len += 7; /* align on byte boundary */
2964 Tracev((stderr, "\ncomprlen %lu(%lu) ", compressed_len >> 3,
2965 compressed_len - 7 * eof));
2967 return compressed_len >> 3;
2970 /* ===========================================================================
2971 * Save the match info and tally the frequency counts. Return true if
2972 * the current block must be flushed.
2974 int ct_tally(dist, lc)
2975 int dist; /* distance of matched string */
2976 int lc; /* match length-MIN_MATCH or unmatched char (if dist==0) */
2978 l_buf[last_lit++] = (uch) lc;
2980 /* lc is the unmatched char */
2981 dyn_ltree[lc].Freq++;
2983 /* Here, lc is the match length - MIN_MATCH */
2984 dist--; /* dist = match distance - 1 */
2985 Assert((ush) dist < (ush) MAX_DIST &&
2986 (ush) lc <= (ush) (MAX_MATCH - MIN_MATCH) &&
2987 (ush) d_code(dist) < (ush) D_CODES, "ct_tally: bad match");
2989 dyn_ltree[length_code[lc] + LITERALS + 1].Freq++;
2990 dyn_dtree[d_code(dist)].Freq++;
2992 d_buf[last_dist++] = (ush) dist;
2997 /* Output the flags if they fill a byte: */
2998 if ((last_lit & 7) == 0) {
2999 flag_buf[last_flags++] = flags;
3000 flags = 0, flag_bit = 1;
3002 /* Try to guess if it is profitable to stop the current block here */
3003 if ((last_lit & 0xfff) == 0) {
3004 /* Compute an upper bound for the compressed length */
3005 ulg out_length = (ulg) last_lit * 8L;
3006 ulg in_length = (ulg) strstart - block_start;
3009 for (dcode = 0; dcode < D_CODES; dcode++) {
3011 (ulg) dyn_dtree[dcode].Freq * (5L + extra_dbits[dcode]);
3016 "\nlast_lit %u, last_dist %u, in %ld, out ~%ld(%ld%%) ",
3017 last_lit, last_dist, in_length, out_length,
3018 100L - out_length * 100L / in_length));
3019 if (last_dist < last_lit / 2 && out_length < in_length / 2)
3022 return (last_lit == LIT_BUFSIZE - 1 || last_dist == DIST_BUFSIZE);
3023 /* We avoid equality with LIT_BUFSIZE because of wraparound at 64K
3024 * on 16 bit machines and because stored blocks are restricted to
3029 /* ===========================================================================
3030 * Send the block data compressed using the given Huffman trees
3032 local void compress_block(ltree, dtree)
3033 ct_data near *ltree; /* literal tree */
3034 ct_data near *dtree; /* distance tree */
3036 unsigned dist; /* distance of matched string */
3037 int lc; /* match length or unmatched char (if dist == 0) */
3038 unsigned lx = 0; /* running index in l_buf */
3039 unsigned dx = 0; /* running index in d_buf */
3040 unsigned fx = 0; /* running index in flag_buf */
3041 uch flag = 0; /* current flags */
3042 unsigned code; /* the code to send */
3043 int extra; /* number of extra bits to send */
3048 flag = flag_buf[fx++];
3050 if ((flag & 1) == 0) {
3051 send_code(lc, ltree); /* send a literal byte */
3052 Tracecv(isgraph(lc), (stderr, " '%c' ", lc));
3054 /* Here, lc is the match length - MIN_MATCH */
3055 code = length_code[lc];
3056 send_code(code + LITERALS + 1, ltree); /* send the length code */
3057 extra = extra_lbits[code];
3059 lc -= base_length[code];
3060 send_bits(lc, extra); /* send the extra length bits */
3063 /* Here, dist is the match distance - 1 */
3064 code = d_code(dist);
3065 Assert(code < D_CODES, "bad d_code");
3067 send_code(code, dtree); /* send the distance code */
3068 extra = extra_dbits[code];
3070 dist -= base_dist[code];
3071 send_bits(dist, extra); /* send the extra distance bits */
3073 } /* literal or match pair ? */
3075 } while (lx < last_lit);
3077 send_code(END_BLOCK, ltree);
3080 /* ===========================================================================
3081 * Set the file type to ASCII or BINARY, using a crude approximation:
3082 * binary if more than 20% of the bytes are <= 6 or >= 128, ascii otherwise.
3083 * IN assertion: the fields freq of dyn_ltree are set and the total of all
3084 * frequencies does not exceed 64K (to fit in an int on 16 bit machines).
3086 local void set_file_type()
3089 unsigned ascii_freq = 0;
3090 unsigned bin_freq = 0;
3093 bin_freq += dyn_ltree[n++].Freq;
3095 ascii_freq += dyn_ltree[n++].Freq;
3096 while (n < LITERALS)
3097 bin_freq += dyn_ltree[n++].Freq;
3098 *file_type = bin_freq > (ascii_freq >> 2) ? BINARY : ASCII;
3099 if (*file_type == BINARY && translate_eol) {
3100 errorMsg("-l used on binary file");
3104 /* util.c -- utility functions for gzip support
3105 * Copyright (C) 1992-1993 Jean-loup Gailly
3106 * This is free software; you can redistribute it and/or modify it under the
3107 * terms of the GNU General Public License, see the file COPYING.
3112 #include <sys/types.h>
3114 #ifdef HAVE_UNISTD_H
3115 # include <unistd.h>
3121 #if defined(STDC_HEADERS) || !defined(NO_STDLIB_H)
3122 # include <stdlib.h>
3127 /* ===========================================================================
3128 * Copy input to output unchanged: zcat == cat with --force.
3129 * IN assertion: insize bytes have already been read in inbuf.
3132 int in, out; /* input and output file descriptors */
3135 while (insize != 0 && (int) insize != EOF) {
3136 write_buf(out, (char *) inbuf, insize);
3137 bytes_out += insize;
3138 insize = read(in, (char *) inbuf, INBUFSIZ);
3140 if ((int) insize == EOF && errno != 0) {
3143 bytes_in = bytes_out;
3147 /* ========================================================================
3148 * Put string s in lower case, return s.
3155 for (t = s; *t; t++)
3160 #if defined(NO_STRING_H) && !defined(STDC_HEADERS)
3162 /* Provide missing strspn and strcspn functions. */
3164 int strspn (const char *s, const char *accept);
3165 int strcspn (const char *s, const char *reject);
3167 /* ========================================================================
3168 * Return the length of the maximum initial segment
3169 * of s which contains only characters in accept.
3171 int strspn(s, accept)
3175 register const char *p;
3176 register const char *a;
3177 register int count = 0;
3179 for (p = s; *p != '\0'; ++p) {
3180 for (a = accept; *a != '\0'; ++a) {
3191 /* ========================================================================
3192 * Return the length of the maximum inital segment of s
3193 * which contains no characters from reject.
3195 int strcspn(s, reject)
3199 register int count = 0;
3201 while (*s != '\0') {
3202 if (strchr(reject, *s++) != NULL)
3209 #endif /* NO_STRING_H */
3211 /* ========================================================================
3212 * Add an environment variable (if any) before argv, and update argc.
3213 * Return the expanded environment variable to be freed later, or NULL
3214 * if no options were added to argv.
3216 #define SEPARATOR " \t" /* separators in env variable */
3218 char *add_envopt(argcp, argvp, env)
3219 int *argcp; /* pointer to argc */
3220 char ***argvp; /* pointer to argv */
3221 char *env; /* name of environment variable */
3223 char *p; /* running pointer through env variable */
3224 char **oargv; /* runs through old argv array */
3225 char **nargv; /* runs through new argv array */
3226 int oargc = *argcp; /* old argc */
3227 int nargc = 0; /* number of arguments in env variable */
3229 env = (char *) getenv(env);
3233 p = (char *) xmalloc(strlen(env) + 1);
3234 env = strcpy(p, env); /* keep env variable intact */
3236 for (p = env; *p; nargc++) { /* move through env */
3237 p += strspn(p, SEPARATOR); /* skip leading separators */
3241 p += strcspn(p, SEPARATOR); /* find end of word */
3243 *p++ = '\0'; /* mark it */
3250 /* Allocate the new argv array, with an extra element just in case
3251 * the original arg list did not end with a NULL.
3253 nargv = (char **) calloc(*argcp + 1, sizeof(char *));
3256 errorMsg(memory_exhausted, "gzip");
3260 /* Copy the program name first */
3262 errorMsg("argc<=0");
3263 *(nargv++) = *(oargv++);
3265 /* Then copy the environment args */
3266 for (p = env; nargc > 0; nargc--) {
3267 p += strspn(p, SEPARATOR); /* skip separators */
3268 *(nargv++) = p; /* store start */
3269 while (*p++); /* skip over word */
3272 /* Finally copy the old args and add a NULL (usual convention) */
3274 *(nargv++) = *(oargv++);
3279 /* ========================================================================
3280 * Display compression ratio on the given stream on 6 characters.
3282 void display_ratio(num, den, file)
3287 long ratio; /* 1000 times the compression ratio */
3290 ratio = 0; /* no compression */
3291 } else if (den < 2147483L) { /* (2**31 -1)/1000 */
3292 ratio = 1000L * num / den;
3294 ratio = num / (den / 1000L);
3302 fprintf(file, "%2ld.%1ld%%", ratio / 10L, ratio % 10L);
3306 /* zip.c -- compress files to the gzip or pkzip format
3307 * Copyright (C) 1992-1993 Jean-loup Gailly
3308 * This is free software; you can redistribute it and/or modify it under the
3309 * terms of the GNU General Public License, see the file COPYING.
3313 #include <sys/types.h>
3315 #ifdef HAVE_UNISTD_H
3316 # include <unistd.h>
3322 local ulg crc; /* crc on uncompressed file data */
3323 long header_bytes; /* number of bytes in gzip header */
3325 /* ===========================================================================
3326 * Deflate in to out.
3327 * IN assertions: the input and output buffers are cleared.
3328 * The variables time_stamp and save_orig_name are initialized.
3331 int in, out; /* input and output file descriptors */
3333 uch flags = 0; /* general purpose bit flags */
3334 ush attr = 0; /* ascii/binary flag */
3335 ush deflate_flags = 0; /* pkzip -es, -en or -ex equivalent */
3341 /* Write the header to the gzip file. See algorithm.doc for the format */
3345 put_byte(GZIP_MAGIC[0]); /* magic header */
3346 put_byte(GZIP_MAGIC[1]);
3347 put_byte(DEFLATED); /* compression method */
3349 put_byte(flags); /* general flags */
3350 put_long(time_stamp);
3352 /* Write deflated file to zip file */
3356 ct_init(&attr, &method);
3357 lm_init(&deflate_flags);
3359 put_byte((uch) deflate_flags); /* extra flags */
3360 put_byte(OS_CODE); /* OS identifier */
3362 header_bytes = (long) outcnt;
3366 /* Write the crc and uncompressed size */
3369 header_bytes += 2 * sizeof(long);
3376 /* ===========================================================================
3377 * Read a new buffer from the current input file, perform end-of-line
3378 * translation, and update the crc and input file size.
3379 * IN assertion: size >= 2 (for end-of-line translation)
3381 int file_read(buf, size)
3387 Assert(insize == 0, "inbuf not empty");
3389 len = read(ifd, buf, size);
3390 if (len == (unsigned) (-1) || len == 0)
3393 crc = updcrc((uch *) buf, len);
projects / oweals / busybox.git / blob