1 /* gzip.c -- this is a stripped down version of gzip I put into busybox, it does
2 * only standard in to standard out with -9 compression. It also requires the
3 * zcat module for some important functions.
5 * Charles P. Wright <cpw@unix.asb.com>
11 #error you need zcat to have gzip support!
14 static const char gzip_usage[] = "gzip\nignores all command line arguments\ncompress stdin to stdout with -9 compression\n";
16 /* gzip.h -- common declarations for all gzip modules
17 * Copyright (C) 1992-1993 Jean-loup Gailly.
18 * This is free software; you can redistribute it and/or modify it under the
19 * terms of the GNU General Public License, see the file COPYING.
22 #if defined(__STDC__) || defined(PROTO)
23 # define OF(args) args
34 /* I don't like nested includes, but the string and io functions are used
38 #if !defined(NO_STRING_H) || defined(STDC_HEADERS)
40 # if !defined(STDC_HEADERS) && !defined(NO_MEMORY_H) && !defined(__GNUC__)
43 # define memzero(s, n) memset ((voidp)(s), 0, (n))
47 # define strrchr rindex
48 # define memcpy(d, s, n) bcopy((s), (d), (n))
49 # define memcmp(s1, s2, n) bcmp((s1), (s2), (n))
50 # define memzero(s, n) bzero((s), (n))
54 # define RETSIGTYPE void
59 typedef unsigned char uch;
60 typedef unsigned short ush;
61 typedef unsigned long ulg;
63 /* Return codes from gzip */
68 /* Compression methods (see algorithm.doc) */
73 /* methods 4 to 7 reserved */
76 extern int method; /* compression method */
78 /* To save memory for 16 bit systems, some arrays are overlaid between
79 * the various modules:
80 * deflate: prev+head window d_buf l_buf outbuf
81 * unlzw: tab_prefix tab_suffix stack inbuf outbuf
82 * inflate: window inbuf
83 * unpack: window inbuf prefix_len
84 * unlzh: left+right window c_table inbuf c_len
85 * For compression, input is done in window[]. For decompression, output
86 * is done in window except for unlzw.
91 # define INBUFSIZ 0x2000 /* input buffer size */
93 # define INBUFSIZ 0x8000 /* input buffer size */
96 #define INBUF_EXTRA 64 /* required by unlzw() */
100 # define OUTBUFSIZ 8192 /* output buffer size */
102 # define OUTBUFSIZ 16384 /* output buffer size */
105 #define OUTBUF_EXTRA 2048 /* required by unlzw() */
109 # define DIST_BUFSIZE 0x2000 /* buffer for distances, see trees.c */
111 # define DIST_BUFSIZE 0x8000 /* buffer for distances, see trees.c */
116 # define EXTERN(type, array) extern type * near array
117 # define DECLARE(type, array, size) type * near array
118 # define ALLOC(type, array, size) { \
119 array = (type*)fcalloc((size_t)(((size)+1L)/2), 2*sizeof(type)); \
120 if (array == NULL) error("insufficient memory"); \
122 # define FREE(array) {if (array != NULL) fcfree(array), array=NULL;}
124 # define EXTERN(type, array) extern type array[]
125 # define DECLARE(type, array, size) type array[size]
126 # define ALLOC(type, array, size)
130 EXTERN(uch, inbuf); /* input buffer */
131 EXTERN(uch, outbuf); /* output buffer */
132 EXTERN(ush, d_buf); /* buffer for distances, see trees.c */
133 EXTERN(uch, window); /* Sliding window and suffix table (unlzw) */
134 #define tab_suffix window
136 # define tab_prefix prev /* hash link (see deflate.c) */
137 # define head (prev+WSIZE) /* hash head (see deflate.c) */
138 EXTERN(ush, tab_prefix); /* prefix code (see unlzw.c) */
140 # define tab_prefix0 prev
141 # define head tab_prefix1
142 EXTERN(ush, tab_prefix0); /* prefix for even codes */
143 EXTERN(ush, tab_prefix1); /* prefix for odd codes */
146 extern unsigned insize; /* valid bytes in inbuf */
147 extern unsigned inptr; /* index of next byte to be processed in inbuf */
148 extern unsigned outcnt; /* bytes in output buffer */
150 extern long bytes_in; /* number of input bytes */
151 extern long bytes_out; /* number of output bytes */
152 extern long header_bytes;/* number of bytes in gzip header */
154 #define isize bytes_in
155 /* for compatibility with old zip sources (to be cleaned) */
157 extern int ifd; /* input file descriptor */
158 extern int ofd; /* output file descriptor */
159 extern char ifname[]; /* input file name or "stdin" */
160 extern char ofname[]; /* output file name or "stdout" */
161 extern char *progname; /* program name */
163 extern long time_stamp; /* original time stamp (modification time) */
164 extern long ifile_size; /* input file size, -1 for devices (debug only) */
166 typedef int file_t; /* Do not use stdio */
167 #define NO_FILE (-1) /* in memory compression */
170 #define PACK_MAGIC "\037\036" /* Magic header for packed files */
171 #define GZIP_MAGIC "\037\213" /* Magic header for gzip files, 1F 8B */
172 #define OLD_GZIP_MAGIC "\037\236" /* Magic header for gzip 0.5 = freeze 1.x */
173 #define LZH_MAGIC "\037\240" /* Magic header for SCO LZH Compress files*/
174 #define PKZIP_MAGIC "\120\113\003\004" /* Magic header for pkzip files */
177 #define ASCII_FLAG 0x01 /* bit 0 set: file probably ascii text */
178 #define CONTINUATION 0x02 /* bit 1 set: continuation of multi-part gzip file */
179 #define EXTRA_FIELD 0x04 /* bit 2 set: extra field present */
180 #define ORIG_NAME 0x08 /* bit 3 set: original file name present */
181 #define COMMENT 0x10 /* bit 4 set: file comment present */
182 #define ENCRYPTED 0x20 /* bit 5 set: file is encrypted */
183 #define RESERVED 0xC0 /* bit 6,7: reserved */
185 /* internal file attribute */
186 #define UNKNOWN 0xffff
191 # define WSIZE 0x8000 /* window size--must be a power of two, and */
192 #endif /* at least 32K for zip's deflate method */
195 #define MAX_MATCH 258
196 /* The minimum and maximum match lengths */
198 #define MIN_LOOKAHEAD (MAX_MATCH+MIN_MATCH+1)
199 /* Minimum amount of lookahead, except at the end of the input file.
200 * See deflate.c for comments about the MIN_MATCH+1.
203 #define MAX_DIST (WSIZE-MIN_LOOKAHEAD)
204 /* In order to simplify the code, particularly on 16 bit machines, match
205 * distances are limited to MAX_DIST instead of WSIZE.
208 extern int decrypt; /* flag to turn on decryption */
209 extern int exit_code; /* program exit code */
210 extern int verbose; /* be verbose (-v) */
211 extern int quiet; /* be quiet (-q) */
212 extern int test; /* check .z file integrity */
213 extern int to_stdout; /* output to stdout (-c) */
214 extern int save_orig_name; /* set if original name must be saved */
216 #define get_byte() (inptr < insize ? inbuf[inptr++] : fill_inbuf(0))
217 #define try_byte() (inptr < insize ? inbuf[inptr++] : fill_inbuf(1))
219 /* put_byte is used for the compressed output, put_ubyte for the
220 * uncompressed output. However unlzw() uses window for its
221 * suffix table instead of its output buffer, so it does not use put_ubyte
222 * (to be cleaned up).
224 #define put_byte(c) {outbuf[outcnt++]=(uch)(c); if (outcnt==OUTBUFSIZ)\
226 #define put_ubyte(c) {window[outcnt++]=(uch)(c); if (outcnt==WSIZE)\
229 /* Output a 16 bit value, lsb first */
230 #define put_short(w) \
231 { if (outcnt < OUTBUFSIZ-2) { \
232 outbuf[outcnt++] = (uch) ((w) & 0xff); \
233 outbuf[outcnt++] = (uch) ((ush)(w) >> 8); \
235 put_byte((uch)((w) & 0xff)); \
236 put_byte((uch)((ush)(w) >> 8)); \
240 /* Output a 32 bit value to the bit stream, lsb first */
241 #define put_long(n) { \
242 put_short((n) & 0xffff); \
243 put_short(((ulg)(n)) >> 16); \
246 #define seekable() 0 /* force sequential output */
247 #define translate_eol 0 /* no option -a yet */
249 #define tolow(c) (isupper(c) ? (c)-'A'+'a' : (c)) /* force to lower case */
251 /* Macros for getting two-byte and four-byte header values */
252 #define SH(p) ((ush)(uch)((p)[0]) | ((ush)(uch)((p)[1]) << 8))
253 #define LG(p) ((ulg)(SH(p)) | ((ulg)(SH((p)+2)) << 16))
255 /* Diagnostic functions */
257 # define Assert(cond,msg) {if(!(cond)) error(msg);}
258 # define Trace(x) fprintf x
259 # define Tracev(x) {if (verbose) fprintf x ;}
260 # define Tracevv(x) {if (verbose>1) fprintf x ;}
261 # define Tracec(c,x) {if (verbose && (c)) fprintf x ;}
262 # define Tracecv(c,x) {if (verbose>1 && (c)) fprintf x ;}
264 # define Assert(cond,msg)
269 # define Tracecv(c,x)
272 #define WARN(msg) {if (!quiet) fprintf msg ; \
273 if (exit_code == OK) exit_code = WARNING;}
275 local void do_exit(int exitcode);
278 extern int zip OF((int in, int out));
279 extern int file_read OF((char *buf, unsigned size));
282 extern int unzip OF((int in, int out));
283 extern int check_zipfile OF((int in));
286 extern int unpack OF((int in, int out));
289 extern int unlzh OF((int in, int out));
292 RETSIGTYPE abort_gzip OF((void));
295 void lm_init OF((ush *flags));
296 ulg deflate OF((void));
299 void ct_init OF((ush *attr, int *method));
300 int ct_tally OF((int dist, int lc));
301 ulg flush_block OF((char *buf, ulg stored_len, int eof));
304 void bi_init OF((file_t zipfile));
305 void send_bits OF((int value, int length));
306 unsigned bi_reverse OF((unsigned value, int length));
307 void bi_windup OF((void));
308 void copy_block OF((char *buf, unsigned len, int header));
309 extern int (*read_buf) OF((char *buf, unsigned size));
312 extern int copy OF((int in, int out));
313 extern ulg updcrc OF((uch *s, unsigned n));
314 extern void clear_bufs OF((void));
315 extern int fill_inbuf OF((int eof_ok));
316 extern void flush_outbuf OF((void));
317 extern void flush_window OF((void));
318 extern void write_buf OF((int fd, voidp buf, unsigned cnt));
319 extern char *strlwr OF((char *s));
320 extern char *add_envopt OF((int *argcp, char ***argvp, char *env));
321 extern void error OF((char *m));
322 extern void warn OF((char *a, char *b));
323 extern void read_error OF((void));
324 extern void write_error OF((void));
325 extern void display_ratio OF((long num, long den, FILE *file));
326 extern voidp xmalloc OF((unsigned int size));
329 extern int inflate OF((void));
330 /* lzw.h -- define the lzw functions.
331 * Copyright (C) 1992-1993 Jean-loup Gailly.
332 * This is free software; you can redistribute it and/or modify it under the
333 * terms of the GNU General Public License, see the file COPYING.
336 #if !defined(OF) && defined(lint)
343 #define INIT_BITS 9 /* Initial number of bits per code */
345 #define BIT_MASK 0x1f /* Mask for 'number of compression bits' */
346 /* Mask 0x20 is reserved to mean a fourth header byte, and 0x40 is free.
347 * It's a pity that old uncompress does not check bit 0x20. That makes
348 * extension of the format actually undesirable because old compress
349 * would just crash on the new format instead of giving a meaningful
350 * error message. It does check the number of bits, but it's more
351 * helpful to say "unsupported format, get a new version" than
352 * "can only handle 16 bits".
355 #define BLOCK_MODE 0x80
356 /* Block compression: if table is full and compression rate is dropping,
357 * clear the dictionary.
360 #define LZW_RESERVED 0x60 /* reserved bits */
362 #define CLEAR 256 /* flush the dictionary */
363 #define FIRST (CLEAR+1) /* first free entry */
365 extern int maxbits; /* max bits per code for LZW */
366 extern int block_mode; /* block compress mode -C compatible with 2.0 */
368 /* revision.h -- define the version number
369 * Copyright (C) 1992-1993 Jean-loup Gailly.
370 * This is free software; you can redistribute it and/or modify it under the
371 * terms of the GNU General Public License, see the file COPYING.
374 #define VERSION "1.2.4"
376 #define REVDATE "18 Aug 93"
378 /* This version does not support compression into old compress format: */
383 /* $Id: gzip.c,v 1.5 1999/10/23 07:09:58 andersen Exp $ */
384 /* tailor.h -- target dependent definitions
385 * Copyright (C) 1992-1993 Jean-loup Gailly.
386 * This is free software; you can redistribute it and/or modify it under the
387 * terms of the GNU General Public License, see the file COPYING.
390 /* The target dependent definitions should be defined here only.
391 * The target dependent functions should be defined in tailor.c.
394 /* $Id: gzip.c,v 1.5 1999/10/23 07:09:58 andersen Exp $ */
396 #if defined(__MSDOS__) && !defined(MSDOS)
400 #if defined(__OS2__) && !defined(OS2)
404 #if defined(OS2) && defined(MSDOS) /* MS C under OS/2 */
410 /* DJGPP version 1.09+ on MS-DOS.
411 * The DJGPP 1.09 stat() function must be upgraded before gzip will
413 * No need for DIRENT, since <unistd.h> defines POSIX_SOURCE which
427 # define HAVE_SYS_UTIME_H
431 # define PATH_SEP2 '\\'
432 # define PATH_SEP3 ':'
433 # define MAX_PATH_LEN 128
434 # define NO_MULTIPLE_DOTS
435 # define MAX_EXT_CHARS 3
436 # define Z_SUFFIX "z"
439 # define STDC_HEADERS
440 # define NO_SIZE_CHECK
441 # define casemap(c) tolow(c) /* Force file names to lower case */
443 # define OS_CODE 0x00
444 # define SET_BINARY_MODE(fd) setmode(fd, O_BINARY)
445 # if !defined(NO_ASM) && !defined(ASMV)
453 # define PATH_SEP2 '\\'
454 # define PATH_SEP3 ':'
455 # define MAX_PATH_LEN 260
457 # define NO_MULTIPLE_DOTS
458 # define MAX_EXT_CHARS 3
459 # define Z_SUFFIX "z"
460 # define casemap(c) tolow(c)
464 # define STDC_HEADERS
466 # define OS_CODE 0x06
467 # define SET_BINARY_MODE(fd) setmode(fd, O_BINARY)
469 # define HAVE_SYS_UTIME_H
476 # define HAVE_SYS_UTIME_H
479 # define EXPAND(argc,argv) \
480 {_response(&argc, &argv); _wildcard(&argc, &argv);}
489 # define EXPAND(argc,argv) \
490 {response_expand(&argc, &argv);}
494 #ifdef WIN32 /* Windows NT */
495 # define HAVE_SYS_UTIME_H
497 # define PATH_SEP2 '\\'
498 # define PATH_SEP3 ':'
499 # define MAX_PATH_LEN 260
502 # define STDC_HEADERS
503 # define SET_BINARY_MODE(fd) setmode(fd, O_BINARY)
507 # define NO_MULTIPLE_DOTS
508 # define MAX_EXT_CHARS 3
509 # define Z_SUFFIX "z"
510 # define casemap(c) tolow(c) /* Force file names to lower case */
512 # define OS_CODE 0x0b
519 /* Turbo C 2.0 does not accept static allocations of large arrays */
520 void * fcalloc (unsigned items, unsigned size);
521 void fcfree (void *ptr);
524 # define fcalloc(nitems,itemsize) halloc((long)(nitems),(itemsize))
525 # define fcfree(ptr) hfree(ptr)
529 # define fcalloc(items,size) calloc((items),(size))
531 # define fcalloc(items,size) malloc((size_t)(items)*(size_t)(size))
533 # define fcfree(ptr) free(ptr)
536 #if defined(VAXC) || defined(VMS)
537 # define PATH_SEP ']'
538 # define PATH_SEP2 ':'
539 # define SUFFIX_SEP ';'
540 # define NO_MULTIPLE_DOTS
541 # define Z_SUFFIX "-gz"
543 # define casemap(c) tolow(c)
544 # define OS_CODE 0x02
545 # define OPTIONS_VAR "GZIP_OPT"
546 # define STDC_HEADERS
548 # define EXPAND(argc,argv) vms_expand_args(&argc,&argv);
550 # define unlink delete
558 # define PATH_SEP2 ':'
559 # define STDC_HEADERS
560 # define OS_CODE 0x01
564 # define HAVE_UNISTD_H
566 # define NO_STDIN_FSTAT
571 # include <fcntl.h> /* for read() and write() */
572 # define direct dirent
573 extern void _expand_args(int *argc, char ***argv);
574 # define EXPAND(argc,argv) _expand_args(&argc,&argv);
575 # undef O_BINARY /* disable useless --ascii option */
579 #if defined(ATARI) || defined(atarist)
580 # ifndef STDC_HEADERS
581 # define STDC_HEADERS
582 # define HAVE_UNISTD_H
586 # define OS_CODE 0x05
588 # define PATH_SEP2 '\\'
589 # define PATH_SEP3 ':'
590 # define MAX_PATH_LEN 128
591 # define NO_MULTIPLE_DOTS
592 # define MAX_EXT_CHARS 3
593 # define Z_SUFFIX "z"
595 # define casemap(c) tolow(c) /* Force file names to lower case */
601 # define PATH_SEP ':'
604 # define NO_STDIN_FSTAT
607 # define chmod(file, mode) (0)
608 # define OPEN(name, flags, mode) open(name, flags)
609 # define OS_CODE 0x07
611 # define isatty(fd) ((fd) <= 2)
615 #ifdef __50SERIES /* Prime/PRIMOS */
616 # define PATH_SEP '>'
617 # define STDC_HEADERS
622 # define NO_STDIN_FSTAT
623 # define NO_SIZE_CHECK
626 # define casemap(c) tolow(c) /* Force file names to lower case */
627 # define put_char(c) put_byte((c) & 0x7F)
628 # define get_char(c) ascii2pascii(get_byte())
629 # define OS_CODE 0x0F /* temporary, subject to change */
631 # undef SIGTERM /* We don't want a signal handler for SIGTERM */
635 #if defined(pyr) && !defined(NOMEMCPY) /* Pyramid */
636 # define NOMEMCPY /* problem with overlapping copies */
640 # define OS_CODE 0x0a
644 # define NO_ST_INO /* don't rely on inode numbers */
648 /* Common defaults */
651 # define OS_CODE 0x03 /* assume Unix */
655 # define PATH_SEP '/'
659 # define casemap(c) (c)
663 # define OPTIONS_VAR "GZIP"
667 # define Z_SUFFIX ".gz"
671 # define MAX_SUFFIX MAX_EXT_CHARS
673 # define MAX_SUFFIX 30
676 #ifndef MAKE_LEGAL_NAME
677 # ifdef NO_MULTIPLE_DOTS
678 # define MAKE_LEGAL_NAME(name) make_simple_name(name)
680 # define MAKE_LEGAL_NAME(name)
686 /* keep at least MIN_PART chars between dots in a file name. */
690 # define EXPAND(argc,argv)
697 #ifndef SET_BINARY_MODE
698 # define SET_BINARY_MODE(fd)
702 # define OPEN(name, flags, mode) open(name, flags, mode)
706 # define get_char() get_byte()
710 # define put_char(c) put_byte(c)
712 /* bits.c -- output variable-length bit strings
713 * Copyright (C) 1992-1993 Jean-loup Gailly
714 * This is free software; you can redistribute it and/or modify it under the
715 * terms of the GNU General Public License, see the file COPYING.
722 * Output variable-length bit strings. Compression can be done
723 * to a file or to memory. (The latter is not supported in this version.)
727 * The PKZIP "deflate" file format interprets compressed file data
728 * as a sequence of bits. Multi-bit strings in the file may cross
729 * byte boundaries without restriction.
731 * The first bit of each byte is the low-order bit.
733 * The routines in this file allow a variable-length bit value to
734 * be output right-to-left (useful for literal values). For
735 * left-to-right output (useful for code strings from the tree routines),
736 * the bits must have been reversed first with bi_reverse().
738 * For in-memory compression, the compressed bit stream goes directly
739 * into the requested output buffer. The input data is read in blocks
740 * by the mem_read() function. The buffer is limited to 64K on 16 bit
745 * void bi_init (FILE *zipfile)
746 * Initialize the bit string routines.
748 * void send_bits (int value, int length)
749 * Write out a bit string, taking the source bits right to
752 * int bi_reverse (int value, int length)
753 * Reverse the bits of a bit string, taking the source bits left to
754 * right and emitting them right to left.
756 * void bi_windup (void)
757 * Write out any remaining bits in an incomplete byte.
759 * void copy_block(char *buf, unsigned len, int header)
760 * Copy a stored block to the zip file, storing first the length and
761 * its one's complement if requested.
769 /* ===========================================================================
770 * Local data used by the "bit string" routines.
773 local file_t zfile; /* output gzip file */
775 local unsigned short bi_buf;
776 /* Output buffer. bits are inserted starting at the bottom (least significant
780 #define Buf_size (8 * 2*sizeof(char))
781 /* Number of bits used within bi_buf. (bi_buf might be implemented on
782 * more than 16 bits on some systems.)
786 /* Number of valid bits in bi_buf. All bits above the last valid bit
790 int (*read_buf) OF((char *buf, unsigned size));
791 /* Current input function. Set to mem_read for in-memory compression */
794 ulg bits_sent; /* bit length of the compressed data */
797 /* ===========================================================================
798 * Initialize the bit string routines.
800 void bi_init (zipfile)
801 file_t zipfile; /* output zip file, NO_FILE for in-memory compression */
810 /* Set the defaults for file compression. They are set by memcompress
811 * for in-memory compression.
813 if (zfile != NO_FILE) {
814 read_buf = file_read;
818 /* ===========================================================================
819 * Send a value on a given number of bits.
820 * IN assertion: length <= 16 and value fits in length bits.
822 void send_bits(value, length)
823 int value; /* value to send */
824 int length; /* number of bits */
827 Tracev((stderr," l %2d v %4x ", length, value));
828 Assert(length > 0 && length <= 15, "invalid length");
829 bits_sent += (ulg)length;
831 /* If not enough room in bi_buf, use (valid) bits from bi_buf and
832 * (16 - bi_valid) bits from value, leaving (width - (16-bi_valid))
833 * unused bits in value.
835 if (bi_valid > (int)Buf_size - length) {
836 bi_buf |= (value << bi_valid);
838 bi_buf = (ush)value >> (Buf_size - bi_valid);
839 bi_valid += length - Buf_size;
841 bi_buf |= value << bi_valid;
846 /* ===========================================================================
847 * Reverse the first len bits of a code, using straightforward code (a faster
848 * method would use a table)
849 * IN assertion: 1 <= len <= 15
851 unsigned bi_reverse(code, len)
852 unsigned code; /* the value to invert */
853 int len; /* its bit length */
855 register unsigned res = 0;
858 code >>= 1, res <<= 1;
863 /* ===========================================================================
864 * Write out any remaining bits in an incomplete byte.
870 } else if (bi_valid > 0) {
876 bits_sent = (bits_sent+7) & ~7;
880 /* ===========================================================================
881 * Copy a stored block to the zip file, storing first the length and its
882 * one's complement if requested.
884 void copy_block(buf, len, header)
885 char *buf; /* the input data */
886 unsigned len; /* its length */
887 int header; /* true if block header must be written */
889 bi_windup(); /* align on byte boundary */
893 put_short((ush)~len);
899 bits_sent += (ulg)len<<3;
904 if (key) zencode(*buf, t);
909 /* deflate.c -- compress data using the deflation algorithm
910 * Copyright (C) 1992-1993 Jean-loup Gailly
911 * This is free software; you can redistribute it and/or modify it under the
912 * terms of the GNU General Public License, see the file COPYING.
918 * Identify new text as repetitions of old text within a fixed-
919 * length sliding window trailing behind the new text.
923 * The "deflation" process depends on being able to identify portions
924 * of the input text which are identical to earlier input (within a
925 * sliding window trailing behind the input currently being processed).
927 * The most straightforward technique turns out to be the fastest for
928 * most input files: try all possible matches and select the longest.
929 * The key feature of this algorithm is that insertions into the string
930 * dictionary are very simple and thus fast, and deletions are avoided
931 * completely. Insertions are performed at each input character, whereas
932 * string matches are performed only when the previous match ends. So it
933 * is preferable to spend more time in matches to allow very fast string
934 * insertions and avoid deletions. The matching algorithm for small
935 * strings is inspired from that of Rabin & Karp. A brute force approach
936 * is used to find longer strings when a small match has been found.
937 * A similar algorithm is used in comic (by Jan-Mark Wams) and freeze
938 * (by Leonid Broukhis).
939 * A previous version of this file used a more sophisticated algorithm
940 * (by Fiala and Greene) which is guaranteed to run in linear amortized
941 * time, but has a larger average cost, uses more memory and is patented.
942 * However the F&G algorithm may be faster for some highly redundant
943 * files if the parameter max_chain_length (described below) is too large.
947 * The idea of lazy evaluation of matches is due to Jan-Mark Wams, and
948 * I found it in 'freeze' written by Leonid Broukhis.
949 * Thanks to many info-zippers for bug reports and testing.
953 * APPNOTE.TXT documentation file in PKZIP 1.93a distribution.
955 * A description of the Rabin and Karp algorithm is given in the book
956 * "Algorithms" by R. Sedgewick, Addison-Wesley, p252.
958 * Fiala,E.R., and Greene,D.H.
959 * Data Compression with Finite Windows, Comm.ACM, 32,4 (1989) 490-595
963 * void lm_init (int pack_level, ush *flags)
964 * Initialize the "longest match" routines for a new file
967 * Processes a new input file and return its compressed length. Sets
968 * the compressed length, crc, deflate flags and internal file
974 /* ===========================================================================
975 * Configuration parameters
978 /* Compile with MEDIUM_MEM to reduce the memory requirements or
979 * with SMALL_MEM to use as little memory as possible. Use BIG_MEM if the
980 * entire input file can be held in memory (not possible on 16 bit systems).
981 * Warning: defining these symbols affects HASH_BITS (see below) and thus
982 * affects the compression ratio. The compressed output
983 * is still correct, and might even be smaller in some cases.
987 # define HASH_BITS 13 /* Number of bits used to hash strings */
990 # define HASH_BITS 14
993 # define HASH_BITS 15
994 /* For portability to 16 bit machines, do not use values above 15. */
997 /* To save space (see unlzw.c), we overlay prev+head with tab_prefix and
998 * window with tab_suffix. Check that we can do this:
1000 #if (WSIZE<<1) > (1<<BITS)
1001 error: cannot overlay window with tab_suffix and prev with tab_prefix0
1003 #if HASH_BITS > BITS-1
1004 error: cannot overlay head with tab_prefix1
1007 #define HASH_SIZE (unsigned)(1<<HASH_BITS)
1008 #define HASH_MASK (HASH_SIZE-1)
1009 #define WMASK (WSIZE-1)
1010 /* HASH_SIZE and WSIZE must be powers of two */
1013 /* Tail of hash chains */
1017 /* speed options for the general purpose bit flag */
1020 # define TOO_FAR 4096
1022 /* Matches of length 3 are discarded if their distance exceeds TOO_FAR */
1024 /* ===========================================================================
1025 * Local data used by the "longest match" routines.
1029 typedef unsigned IPos;
1030 /* A Pos is an index in the character window. We use short instead of int to
1031 * save space in the various tables. IPos is used only for parameter passing.
1034 /* DECLARE(uch, window, 2L*WSIZE); */
1035 /* Sliding window. Input bytes are read into the second half of the window,
1036 * and move to the first half later to keep a dictionary of at least WSIZE
1037 * bytes. With this organization, matches are limited to a distance of
1038 * WSIZE-MAX_MATCH bytes, but this ensures that IO is always
1039 * performed with a length multiple of the block size. Also, it limits
1040 * the window size to 64K, which is quite useful on MSDOS.
1041 * To do: limit the window size to WSIZE+BSZ if SMALL_MEM (the code would
1042 * be less efficient).
1045 /* DECLARE(Pos, prev, WSIZE); */
1046 /* Link to older string with same hash index. To limit the size of this
1047 * array to 64K, this link is maintained only for the last 32K strings.
1048 * An index in this array is thus a window index modulo 32K.
1051 /* DECLARE(Pos, head, 1<<HASH_BITS); */
1052 /* Heads of the hash chains or NIL. */
1054 ulg window_size = (ulg)2*WSIZE;
1055 /* window size, 2*WSIZE except for MMAP or BIG_MEM, where it is the
1056 * input file length plus MIN_LOOKAHEAD.
1060 /* window position at the beginning of the current output block. Gets
1061 * negative when the window is moved backwards.
1064 local unsigned ins_h; /* hash index of string to be inserted */
1066 #define H_SHIFT ((HASH_BITS+MIN_MATCH-1)/MIN_MATCH)
1067 /* Number of bits by which ins_h and del_h must be shifted at each
1068 * input step. It must be such that after MIN_MATCH steps, the oldest
1069 * byte no longer takes part in the hash key, that is:
1070 * H_SHIFT * MIN_MATCH >= HASH_BITS
1073 unsigned int near prev_length;
1074 /* Length of the best match at previous step. Matches not greater than this
1075 * are discarded. This is used in the lazy match evaluation.
1078 unsigned near strstart; /* start of string to insert */
1079 unsigned near match_start; /* start of matching string */
1080 local int eofile; /* flag set at end of input file */
1081 local unsigned lookahead; /* number of valid bytes ahead in window */
1083 unsigned near max_chain_length;
1084 /* To speed up deflation, hash chains are never searched beyond this length.
1085 * A higher limit improves compression ratio but degrades the speed.
1088 local unsigned int max_lazy_match;
1089 /* Attempt to find a better match only when the current match is strictly
1090 * smaller than this value. This mechanism is used only for compression
1093 #define max_insert_length max_lazy_match
1094 /* Insert new strings in the hash table only if the match length
1095 * is not greater than this length. This saves time but degrades compression.
1096 * max_insert_length is used only for compression levels <= 3.
1099 unsigned near good_match;
1100 /* Use a faster search when the previous match is longer than this */
1103 /* Values for max_lazy_match, good_match and max_chain_length, depending on
1104 * the desired pack level (0..9). The values given below have been tuned to
1105 * exclude worst case performance for pathological files. Better values may be
1106 * found for specific files.
1109 typedef struct config {
1110 ush good_length; /* reduce lazy search above this match length */
1111 ush max_lazy; /* do not perform lazy search above this match length */
1112 ush nice_length; /* quit search above this match length */
1117 # define nice_match MAX_MATCH
1119 int near nice_match; /* Stop searching when current match exceeds this */
1122 local config configuration_table =
1123 /* 9 */ {32, 258, 258, 4096}; /* maximum compression */
1125 /* Note: the deflate() code requires max_lazy >= MIN_MATCH and max_chain >= 4
1126 * For deflate_fast() (levels <= 3) good is ignored and lazy has a different
1131 /* result of memcmp for equal strings */
1133 /* ===========================================================================
1134 * Prototypes for local functions.
1136 local void fill_window OF((void));
1138 int longest_match OF((IPos cur_match));
1140 void match_init OF((void)); /* asm code initialization */
1144 local void check_match OF((IPos start, IPos match, int length));
1147 /* ===========================================================================
1148 * Update a hash value with the given input byte
1149 * IN assertion: all calls to to UPDATE_HASH are made with consecutive
1150 * input characters, so that a running hash key can be computed from the
1151 * previous key instead of complete recalculation each time.
1153 #define UPDATE_HASH(h,c) (h = (((h)<<H_SHIFT) ^ (c)) & HASH_MASK)
1155 /* ===========================================================================
1156 * Insert string s in the dictionary and set match_head to the previous head
1157 * of the hash chain (the most recent string with same hash key). Return
1158 * the previous length of the hash chain.
1159 * IN assertion: all calls to to INSERT_STRING are made with consecutive
1160 * input characters and the first MIN_MATCH bytes of s are valid
1161 * (except for the last MIN_MATCH-1 bytes of the input file).
1163 #define INSERT_STRING(s, match_head) \
1164 (UPDATE_HASH(ins_h, window[(s) + MIN_MATCH-1]), \
1165 prev[(s) & WMASK] = match_head = head[ins_h], \
1168 /* ===========================================================================
1169 * Initialize the "longest match" routines for a new file
1171 void lm_init (flags)
1172 ush *flags; /* general purpose bit flag */
1174 register unsigned j;
1176 /* Initialize the hash table. */
1177 #if defined(MAXSEG_64K) && HASH_BITS == 15
1178 for (j = 0; j < HASH_SIZE; j++) head[j] = NIL;
1180 memzero((char*)head, HASH_SIZE*sizeof(*head));
1182 /* prev will be initialized on the fly */
1184 /* Set the default configuration parameters:
1186 max_lazy_match = configuration_table.max_lazy;
1187 good_match = configuration_table.good_length;
1189 nice_match = configuration_table.nice_length;
1191 max_chain_length = configuration_table.max_chain;
1193 /* ??? reduce max_chain_length for binary files */
1198 match_init(); /* initialize the asm code */
1201 lookahead = read_buf((char*)window,
1202 sizeof(int) <= 2 ? (unsigned)WSIZE : 2*WSIZE);
1204 if (lookahead == 0 || lookahead == (unsigned)EOF) {
1205 eofile = 1, lookahead = 0;
1209 /* Make sure that we always have enough lookahead. This is important
1210 * if input comes from a device such as a tty.
1212 while (lookahead < MIN_LOOKAHEAD && !eofile) fill_window();
1215 for (j=0; j<MIN_MATCH-1; j++) UPDATE_HASH(ins_h, window[j]);
1216 /* If lookahead < MIN_MATCH, ins_h is garbage, but this is
1217 * not important since only literal bytes will be emitted.
1221 /* ===========================================================================
1222 * Set match_start to the longest match starting at the given string and
1223 * return its length. Matches shorter or equal to prev_length are discarded,
1224 * in which case the result is equal to prev_length and match_start is
1226 * IN assertions: cur_match is the head of the hash chain for the current
1227 * string (strstart) and its distance is <= MAX_DIST, and prev_length >= 1
1230 /* For MSDOS, OS/2 and 386 Unix, an optimized version is in match.asm or
1231 * match.s. The code is functionally equivalent, so you can use the C version
1234 int longest_match(cur_match)
1235 IPos cur_match; /* current match */
1237 unsigned chain_length = max_chain_length; /* max hash chain length */
1238 register uch *scan = window + strstart; /* current string */
1239 register uch *match; /* matched string */
1240 register int len; /* length of current match */
1241 int best_len = prev_length; /* best match length so far */
1242 IPos limit = strstart > (IPos)MAX_DIST ? strstart - (IPos)MAX_DIST : NIL;
1243 /* Stop when cur_match becomes <= limit. To simplify the code,
1244 * we prevent matches with the string of window index 0.
1247 /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16.
1248 * It is easy to get rid of this optimization if necessary.
1250 #if HASH_BITS < 8 || MAX_MATCH != 258
1251 error: Code too clever
1255 /* Compare two bytes at a time. Note: this is not always beneficial.
1256 * Try with and without -DUNALIGNED_OK to check.
1258 register uch *strend = window + strstart + MAX_MATCH - 1;
1259 register ush scan_start = *(ush*)scan;
1260 register ush scan_end = *(ush*)(scan+best_len-1);
1262 register uch *strend = window + strstart + MAX_MATCH;
1263 register uch scan_end1 = scan[best_len-1];
1264 register uch scan_end = scan[best_len];
1267 /* Do not waste too much time if we already have a good match: */
1268 if (prev_length >= good_match) {
1271 Assert(strstart <= window_size-MIN_LOOKAHEAD, "insufficient lookahead");
1274 Assert(cur_match < strstart, "no future");
1275 match = window + cur_match;
1277 /* Skip to next match if the match length cannot increase
1278 * or if the match length is less than 2:
1280 #if (defined(UNALIGNED_OK) && MAX_MATCH == 258)
1281 /* This code assumes sizeof(unsigned short) == 2. Do not use
1282 * UNALIGNED_OK if your compiler uses a different size.
1284 if (*(ush*)(match+best_len-1) != scan_end ||
1285 *(ush*)match != scan_start) continue;
1287 /* It is not necessary to compare scan[2] and match[2] since they are
1288 * always equal when the other bytes match, given that the hash keys
1289 * are equal and that HASH_BITS >= 8. Compare 2 bytes at a time at
1290 * strstart+3, +5, ... up to strstart+257. We check for insufficient
1291 * lookahead only every 4th comparison; the 128th check will be made
1292 * at strstart+257. If MAX_MATCH-2 is not a multiple of 8, it is
1293 * necessary to put more guard bytes at the end of the window, or
1294 * to check more often for insufficient lookahead.
1298 } while (*(ush*)(scan+=2) == *(ush*)(match+=2) &&
1299 *(ush*)(scan+=2) == *(ush*)(match+=2) &&
1300 *(ush*)(scan+=2) == *(ush*)(match+=2) &&
1301 *(ush*)(scan+=2) == *(ush*)(match+=2) &&
1303 /* The funny "do {}" generates better code on most compilers */
1305 /* Here, scan <= window+strstart+257 */
1306 Assert(scan <= window+(unsigned)(window_size-1), "wild scan");
1307 if (*scan == *match) scan++;
1309 len = (MAX_MATCH - 1) - (int)(strend-scan);
1310 scan = strend - (MAX_MATCH-1);
1312 #else /* UNALIGNED_OK */
1314 if (match[best_len] != scan_end ||
1315 match[best_len-1] != scan_end1 ||
1317 *++match != scan[1]) continue;
1319 /* The check at best_len-1 can be removed because it will be made
1320 * again later. (This heuristic is not always a win.)
1321 * It is not necessary to compare scan[2] and match[2] since they
1322 * are always equal when the other bytes match, given that
1323 * the hash keys are equal and that HASH_BITS >= 8.
1327 /* We check for insufficient lookahead only every 8th comparison;
1328 * the 256th check will be made at strstart+258.
1331 } while (*++scan == *++match && *++scan == *++match &&
1332 *++scan == *++match && *++scan == *++match &&
1333 *++scan == *++match && *++scan == *++match &&
1334 *++scan == *++match && *++scan == *++match &&
1337 len = MAX_MATCH - (int)(strend - scan);
1338 scan = strend - MAX_MATCH;
1340 #endif /* UNALIGNED_OK */
1342 if (len > best_len) {
1343 match_start = cur_match;
1345 if (len >= nice_match) break;
1347 scan_end = *(ush*)(scan+best_len-1);
1349 scan_end1 = scan[best_len-1];
1350 scan_end = scan[best_len];
1353 } while ((cur_match = prev[cur_match & WMASK]) > limit
1354 && --chain_length != 0);
1361 /* ===========================================================================
1362 * Check that the match at match_start is indeed a match.
1364 local void check_match(start, match, length)
1368 /* check that the match is indeed a match */
1369 if (memcmp((char*)window + match,
1370 (char*)window + start, length) != EQUAL) {
1372 " start %d, match %d, length %d\n",
1373 start, match, length);
1374 error("invalid match");
1377 fprintf(stderr,"\\[%d,%d]", start-match, length);
1378 do { putc(window[start++], stderr); } while (--length != 0);
1382 # define check_match(start, match, length)
1385 /* ===========================================================================
1386 * Fill the window when the lookahead becomes insufficient.
1387 * Updates strstart and lookahead, and sets eofile if end of input file.
1388 * IN assertion: lookahead < MIN_LOOKAHEAD && strstart + lookahead > 0
1389 * OUT assertions: at least one byte has been read, or eofile is set;
1390 * file reads are performed for at least two bytes (required for the
1391 * translate_eol option).
1393 local void fill_window()
1395 register unsigned n, m;
1396 unsigned more = (unsigned)(window_size - (ulg)lookahead - (ulg)strstart);
1397 /* Amount of free space at the end of the window. */
1399 /* If the window is almost full and there is insufficient lookahead,
1400 * move the upper half to the lower one to make room in the upper half.
1402 if (more == (unsigned)EOF) {
1403 /* Very unlikely, but possible on 16 bit machine if strstart == 0
1404 * and lookahead == 1 (input done one byte at time)
1407 } else if (strstart >= WSIZE+MAX_DIST) {
1408 /* By the IN assertion, the window is not empty so we can't confuse
1409 * more == 0 with more == 64K on a 16 bit machine.
1411 Assert(window_size == (ulg)2*WSIZE, "no sliding with BIG_MEM");
1413 memcpy((char*)window, (char*)window+WSIZE, (unsigned)WSIZE);
1414 match_start -= WSIZE;
1415 strstart -= WSIZE; /* we now have strstart >= MAX_DIST: */
1417 block_start -= (long) WSIZE;
1419 for (n = 0; n < HASH_SIZE; n++) {
1421 head[n] = (Pos)(m >= WSIZE ? m-WSIZE : NIL);
1423 for (n = 0; n < WSIZE; n++) {
1425 prev[n] = (Pos)(m >= WSIZE ? m-WSIZE : NIL);
1426 /* If n is not on any hash chain, prev[n] is garbage but
1427 * its value will never be used.
1432 /* At this point, more >= 2 */
1434 n = read_buf((char*)window+strstart+lookahead, more);
1435 if (n == 0 || n == (unsigned)EOF) {
1443 /* ===========================================================================
1444 * Flush the current block, with given end-of-file flag.
1445 * IN assertion: strstart is set to the end of the current match.
1447 #define FLUSH_BLOCK(eof) \
1448 flush_block(block_start >= 0L ? (char*)&window[(unsigned)block_start] : \
1449 (char*)NULL, (long)strstart - block_start, (eof))
1451 /* ===========================================================================
1452 * Same as above, but achieves better compression. We use a lazy
1453 * evaluation for matches: a match is finally adopted only if there is
1454 * no better match at the next window position.
1458 IPos hash_head; /* head of hash chain */
1459 IPos prev_match; /* previous match */
1460 int flush; /* set if current block must be flushed */
1461 int match_available = 0; /* set if previous match exists */
1462 register unsigned match_length = MIN_MATCH-1; /* length of best match */
1464 extern long isize; /* byte length of input file, for debug only */
1467 /* Process the input block. */
1468 while (lookahead != 0) {
1469 /* Insert the string window[strstart .. strstart+2] in the
1470 * dictionary, and set hash_head to the head of the hash chain:
1472 INSERT_STRING(strstart, hash_head);
1474 /* Find the longest match, discarding those <= prev_length.
1476 prev_length = match_length, prev_match = match_start;
1477 match_length = MIN_MATCH-1;
1479 if (hash_head != NIL && prev_length < max_lazy_match &&
1480 strstart - hash_head <= MAX_DIST) {
1481 /* To simplify the code, we prevent matches with the string
1482 * of window index 0 (in particular we have to avoid a match
1483 * of the string with itself at the start of the input file).
1485 match_length = longest_match (hash_head);
1486 /* longest_match() sets match_start */
1487 if (match_length > lookahead) match_length = lookahead;
1489 /* Ignore a length 3 match if it is too distant: */
1490 if (match_length == MIN_MATCH && strstart-match_start > TOO_FAR){
1491 /* If prev_match is also MIN_MATCH, match_start is garbage
1492 * but we will ignore the current match anyway.
1497 /* If there was a match at the previous step and the current
1498 * match is not better, output the previous match:
1500 if (prev_length >= MIN_MATCH && match_length <= prev_length) {
1502 check_match(strstart-1, prev_match, prev_length);
1504 flush = ct_tally(strstart-1-prev_match, prev_length - MIN_MATCH);
1506 /* Insert in hash table all strings up to the end of the match.
1507 * strstart-1 and strstart are already inserted.
1509 lookahead -= prev_length-1;
1513 INSERT_STRING(strstart, hash_head);
1514 /* strstart never exceeds WSIZE-MAX_MATCH, so there are
1515 * always MIN_MATCH bytes ahead. If lookahead < MIN_MATCH
1516 * these bytes are garbage, but it does not matter since the
1517 * next lookahead bytes will always be emitted as literals.
1519 } while (--prev_length != 0);
1520 match_available = 0;
1521 match_length = MIN_MATCH-1;
1523 if (flush) FLUSH_BLOCK(0), block_start = strstart;
1525 } else if (match_available) {
1526 /* If there was no match at the previous position, output a
1527 * single literal. If there was a match but the current match
1528 * is longer, truncate the previous match to a single literal.
1530 Tracevv((stderr,"%c",window[strstart-1]));
1531 if (ct_tally (0, window[strstart-1])) {
1532 FLUSH_BLOCK(0), block_start = strstart;
1537 /* There is no previous match to compare with, wait for
1538 * the next step to decide.
1540 match_available = 1;
1544 Assert (strstart <= isize && lookahead <= isize, "a bit too far");
1546 /* Make sure that we always have enough lookahead, except
1547 * at the end of the input file. We need MAX_MATCH bytes
1548 * for the next match, plus MIN_MATCH bytes to insert the
1549 * string following the next match.
1551 while (lookahead < MIN_LOOKAHEAD && !eofile) fill_window();
1553 if (match_available) ct_tally (0, window[strstart-1]);
1555 return FLUSH_BLOCK(1); /* eof */
1557 /* gzip (GNU zip) -- compress files with zip algorithm and 'compress' interface
1558 * Copyright (C) 1992-1993 Jean-loup Gailly
1559 * The unzip code was written and put in the public domain by Mark Adler.
1560 * Portions of the lzw code are derived from the public domain 'compress'
1561 * written by Spencer Thomas, Joe Orost, James Woods, Jim McKie, Steve Davies,
1562 * Ken Turkowski, Dave Mack and Peter Jannesen.
1564 * See the license_msg below and the file COPYING for the software license.
1565 * See the file algorithm.doc for the compression algorithms and file formats.
1568 /* Compress files with zip algorithm and 'compress' interface.
1569 * See usage() and help() functions below for all options.
1571 * file.gz: compressed file with same mode, owner, and utimes
1572 * or stdout with -c option or if stdin used as input.
1573 * If the output file name had to be truncated, the original name is kept
1574 * in the compressed file.
1575 * On MSDOS, file.tmp -> file.tmz. On VMS, file.tmp -> file.tmp-gz.
1577 * Using gz on MSDOS would create too many file name conflicts. For
1578 * example, foo.txt -> foo.tgz (.tgz must be reserved as shorthand for
1579 * tar.gz). Similarly, foo.dir and foo.doc would both be mapped to foo.dgz.
1580 * I also considered 12345678.txt -> 12345txt.gz but this truncates the name
1581 * too heavily. There is no ideal solution given the MSDOS 8+3 limitation.
1583 * For the meaning of all compilation flags, see comments in Makefile.in.
1587 #include <sys/types.h>
1589 #include <sys/stat.h>
1595 # include <sys/time.h>
1604 #ifdef HAVE_UNISTD_H
1605 # include <unistd.h>
1608 #if defined(STDC_HEADERS) || !defined(NO_STDLIB_H)
1609 # include <stdlib.h>
1615 # include <dirent.h>
1616 typedef struct dirent dir_type;
1617 # define NLENGTH(dirent) ((int)strlen((dirent)->d_name))
1618 # define DIR_OPT "DIRENT"
1620 # define NLENGTH(dirent) ((dirent)->d_namlen)
1622 # include <sys/dir.h>
1623 typedef struct direct dir_type;
1624 # define DIR_OPT "SYSDIR"
1627 # include <sys/ndir.h>
1628 typedef struct direct dir_type;
1629 # define DIR_OPT "SYSNDIR"
1633 typedef struct direct dir_type;
1634 # define DIR_OPT "NDIR"
1637 # define DIR_OPT "NO_DIR"
1646 # define TIME_OPT "UTIME"
1648 # ifdef HAVE_SYS_UTIME_H
1649 # include <sys/utime.h>
1650 # define TIME_OPT "SYS_UTIME"
1656 # define TIME_OPT ""
1660 # define TIME_OPT "NO_UTIME"
1663 #if !defined(S_ISDIR) && defined(S_IFDIR)
1664 # define S_ISDIR(m) (((m) & S_IFMT) == S_IFDIR)
1666 #if !defined(S_ISREG) && defined(S_IFREG)
1667 # define S_ISREG(m) (((m) & S_IFMT) == S_IFREG)
1670 typedef RETSIGTYPE (*sig_type) OF((int));
1673 # define O_BINARY 0 /* creation mode for open() */
1677 /* Pure BSD system? */
1678 # include <sys/file.h>
1680 # define O_CREAT FCREAT
1683 # define O_EXCL FEXCL
1688 # define S_IRUSR 0400
1691 # define S_IWUSR 0200
1693 #define RW_USER (S_IRUSR | S_IWUSR) /* creation mode for open() */
1695 #ifndef MAX_PATH_LEN
1696 # define MAX_PATH_LEN 1024 /* max pathname length */
1705 off_t lseek OF((int fd, off_t offset, int whence));
1708 /* Separator for file name parts (see shorten_name()) */
1709 #ifdef NO_MULTIPLE_DOTS
1710 # define PART_SEP "-"
1712 # define PART_SEP "."
1715 /* global buffers */
1717 DECLARE(uch, inbuf, INBUFSIZ +INBUF_EXTRA);
1718 DECLARE(uch, outbuf, OUTBUFSIZ+OUTBUF_EXTRA);
1719 DECLARE(ush, d_buf, DIST_BUFSIZE);
1720 DECLARE(uch, window, 2L*WSIZE);
1722 DECLARE(ush, tab_prefix, 1L<<BITS);
1724 DECLARE(ush, tab_prefix0, 1L<<(BITS-1));
1725 DECLARE(ush, tab_prefix1, 1L<<(BITS-1));
1728 /* local variables */
1730 int ascii = 0; /* convert end-of-lines to local OS conventions */
1731 int to_stdout = 0; /* output to stdout (-c) */
1732 int decompress = 0; /* decompress (-d) */
1733 int no_name = -1; /* don't save or restore the original file name */
1734 int no_time = -1; /* don't save or restore the original file time */
1735 int foreground; /* set if program run in foreground */
1736 char *progname; /* program name */
1737 static int method = DEFLATED;/* compression method */
1738 static int exit_code = OK; /* program exit code */
1739 int save_orig_name; /* set if original name must be saved */
1740 int last_member; /* set for .zip and .Z files */
1741 int part_nb; /* number of parts in .gz file */
1742 long time_stamp; /* original time stamp (modification time) */
1743 long ifile_size; /* input file size, -1 for devices (debug only) */
1744 char *env; /* contents of GZIP env variable */
1745 char **args = NULL; /* argv pointer if GZIP env variable defined */
1746 char z_suffix[MAX_SUFFIX+1]; /* default suffix (can be set with --suffix) */
1747 int z_len; /* strlen(z_suffix) */
1749 long bytes_in; /* number of input bytes */
1750 long bytes_out; /* number of output bytes */
1751 char ifname[MAX_PATH_LEN]; /* input file name */
1752 char ofname[MAX_PATH_LEN]; /* output file name */
1753 int remove_ofname = 0; /* remove output file on error */
1754 struct stat istat; /* status for input file */
1755 int ifd; /* input file descriptor */
1756 int ofd; /* output file descriptor */
1757 unsigned insize; /* valid bytes in inbuf */
1758 unsigned inptr; /* index of next byte to be processed in inbuf */
1759 unsigned outcnt; /* bytes in output buffer */
1761 /* local functions */
1763 local void treat_stdin OF((void));
1764 static int (*work) OF((int infile, int outfile)) = zip; /* function to call */
1766 #define strequ(s1, s2) (strcmp((s1),(s2)) == 0)
1768 /* ======================================================================== */
1769 // int main (argc, argv)
1772 int gzip_main(int argc, char * * argv)
1774 foreground = signal(SIGINT, SIG_IGN) != SIG_IGN;
1776 (void) signal (SIGINT, (sig_type)abort_gzip);
1779 if (signal(SIGTERM, SIG_IGN) != SIG_IGN) {
1780 (void) signal(SIGTERM, (sig_type)abort_gzip);
1784 if (signal(SIGHUP, SIG_IGN) != SIG_IGN) {
1785 (void) signal(SIGHUP, (sig_type)abort_gzip);
1789 strncpy(z_suffix, Z_SUFFIX, sizeof(z_suffix)-1);
1790 z_len = strlen(z_suffix);
1794 /* Allocate all global buffers (for DYN_ALLOC option) */
1795 ALLOC(uch, inbuf, INBUFSIZ +INBUF_EXTRA);
1796 ALLOC(uch, outbuf, OUTBUFSIZ+OUTBUF_EXTRA);
1797 ALLOC(ush, d_buf, DIST_BUFSIZE);
1798 ALLOC(uch, window, 2L*WSIZE);
1800 ALLOC(ush, tab_prefix, 1L<<BITS);
1802 ALLOC(ush, tab_prefix0, 1L<<(BITS-1));
1803 ALLOC(ush, tab_prefix1, 1L<<(BITS-1));
1806 /* And get to work */
1809 return exit_code; /* just to avoid lint warning */
1812 /* ========================================================================
1813 * Compress or decompress stdin
1815 local void treat_stdin()
1817 SET_BINARY_MODE(fileno(stdout));
1818 strcpy(ifname, "stdin");
1819 strcpy(ofname, "stdout");
1821 /* Get the time stamp on the input file. */
1822 time_stamp = 0; /* time unknown by default */
1824 ifile_size = -1L; /* convention for unknown size */
1826 clear_bufs(); /* clear input and output buffers */
1830 /* Actually do the compression/decompression. Loop over zipped members.
1832 if ((*work)(fileno(stdin), fileno(stdout)) != OK) return;
1835 /* ========================================================================
1836 * Free all dynamically allocated variables and exit with the given code.
1838 local void do_exit(int exitcode)
1840 static int in_exit = 0;
1842 if (in_exit) exit(exitcode);
1844 if (env != NULL) free(env), env = NULL;
1845 if (args != NULL) free((char*)args), args = NULL;
1858 /* trees.c -- output deflated data using Huffman coding
1859 * Copyright (C) 1992-1993 Jean-loup Gailly
1860 * This is free software; you can redistribute it and/or modify it under the
1861 * terms of the GNU General Public License, see the file COPYING.
1867 * Encode various sets of source values using variable-length
1868 * binary code trees.
1872 * The PKZIP "deflation" process uses several Huffman trees. The more
1873 * common source values are represented by shorter bit sequences.
1875 * Each code tree is stored in the ZIP file in a compressed form
1876 * which is itself a Huffman encoding of the lengths of
1877 * all the code strings (in ascending order by source values).
1878 * The actual code strings are reconstructed from the lengths in
1879 * the UNZIP process, as described in the "application note"
1880 * (APPNOTE.TXT) distributed as part of PKWARE's PKZIP program.
1885 * Data Compression: Techniques and Applications, pp. 53-55.
1886 * Lifetime Learning Publications, 1985. ISBN 0-534-03418-7.
1889 * Data Compression: Methods and Theory, pp. 49-50.
1890 * Computer Science Press, 1988. ISBN 0-7167-8156-5.
1894 * Addison-Wesley, 1983. ISBN 0-201-06672-6.
1898 * void ct_init (ush *attr, int *methodp)
1899 * Allocate the match buffer, initialize the various tables and save
1900 * the location of the internal file attribute (ascii/binary) and
1901 * method (DEFLATE/STORE)
1903 * void ct_tally (int dist, int lc);
1904 * Save the match info and tally the frequency counts.
1906 * long flush_block (char *buf, ulg stored_len, int eof)
1907 * Determine the best encoding for the current block: dynamic trees,
1908 * static trees or store, and output the encoded block to the zip
1909 * file. Returns the total compressed length for the file so far.
1915 /* ===========================================================================
1920 /* All codes must not exceed MAX_BITS bits */
1922 #define MAX_BL_BITS 7
1923 /* Bit length codes must not exceed MAX_BL_BITS bits */
1925 #define LENGTH_CODES 29
1926 /* number of length codes, not counting the special END_BLOCK code */
1928 #define LITERALS 256
1929 /* number of literal bytes 0..255 */
1931 #define END_BLOCK 256
1932 /* end of block literal code */
1934 #define L_CODES (LITERALS+1+LENGTH_CODES)
1935 /* number of Literal or Length codes, including the END_BLOCK code */
1938 /* number of distance codes */
1941 /* number of codes used to transfer the bit lengths */
1944 local int near extra_lbits[LENGTH_CODES] /* extra bits for each length code */
1945 = {0,0,0,0,0,0,0,0,1,1,1,1,2,2,2,2,3,3,3,3,4,4,4,4,5,5,5,5,0};
1947 local int near extra_dbits[D_CODES] /* extra bits for each distance code */
1948 = {0,0,0,0,1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,13,13};
1950 local int near extra_blbits[BL_CODES]/* extra bits for each bit length code */
1951 = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2,3,7};
1953 #define STORED_BLOCK 0
1954 #define STATIC_TREES 1
1956 /* The three kinds of block type */
1960 # define LIT_BUFSIZE 0x2000
1963 # define LIT_BUFSIZE 0x4000
1965 # define LIT_BUFSIZE 0x8000
1969 #ifndef DIST_BUFSIZE
1970 # define DIST_BUFSIZE LIT_BUFSIZE
1972 /* Sizes of match buffers for literals/lengths and distances. There are
1973 * 4 reasons for limiting LIT_BUFSIZE to 64K:
1974 * - frequencies can be kept in 16 bit counters
1975 * - if compression is not successful for the first block, all input data is
1976 * still in the window so we can still emit a stored block even when input
1977 * comes from standard input. (This can also be done for all blocks if
1978 * LIT_BUFSIZE is not greater than 32K.)
1979 * - if compression is not successful for a file smaller than 64K, we can
1980 * even emit a stored file instead of a stored block (saving 5 bytes).
1981 * - creating new Huffman trees less frequently may not provide fast
1982 * adaptation to changes in the input data statistics. (Take for
1983 * example a binary file with poorly compressible code followed by
1984 * a highly compressible string table.) Smaller buffer sizes give
1985 * fast adaptation but have of course the overhead of transmitting trees
1987 * - I can't count above 4
1988 * The current code is general and allows DIST_BUFSIZE < LIT_BUFSIZE (to save
1989 * memory at the expense of compression). Some optimizations would be possible
1990 * if we rely on DIST_BUFSIZE == LIT_BUFSIZE.
1992 #if LIT_BUFSIZE > INBUFSIZ
1993 error cannot overlay l_buf and inbuf
1997 /* repeat previous bit length 3-6 times (2 bits of repeat count) */
1999 #define REPZ_3_10 17
2000 /* repeat a zero length 3-10 times (3 bits of repeat count) */
2002 #define REPZ_11_138 18
2003 /* repeat a zero length 11-138 times (7 bits of repeat count) */
2005 /* ===========================================================================
2009 /* Data structure describing a single value and its code string. */
2010 typedef struct ct_data {
2012 ush freq; /* frequency count */
2013 ush code; /* bit string */
2016 ush dad; /* father node in Huffman tree */
2017 ush len; /* length of bit string */
2021 #define Freq fc.freq
2022 #define Code fc.code
2026 #define HEAP_SIZE (2*L_CODES+1)
2027 /* maximum heap size */
2029 local ct_data near dyn_ltree[HEAP_SIZE]; /* literal and length tree */
2030 local ct_data near dyn_dtree[2*D_CODES+1]; /* distance tree */
2032 local ct_data near static_ltree[L_CODES+2];
2033 /* The static literal tree. Since the bit lengths are imposed, there is no
2034 * need for the L_CODES extra codes used during heap construction. However
2035 * The codes 286 and 287 are needed to build a canonical tree (see ct_init
2039 local ct_data near static_dtree[D_CODES];
2040 /* The static distance tree. (Actually a trivial tree since all codes use
2044 local ct_data near bl_tree[2*BL_CODES+1];
2045 /* Huffman tree for the bit lengths */
2047 typedef struct tree_desc {
2048 ct_data near *dyn_tree; /* the dynamic tree */
2049 ct_data near *static_tree; /* corresponding static tree or NULL */
2050 int near *extra_bits; /* extra bits for each code or NULL */
2051 int extra_base; /* base index for extra_bits */
2052 int elems; /* max number of elements in the tree */
2053 int max_length; /* max bit length for the codes */
2054 int max_code; /* largest code with non zero frequency */
2057 local tree_desc near l_desc =
2058 {dyn_ltree, static_ltree, extra_lbits, LITERALS+1, L_CODES, MAX_BITS, 0};
2060 local tree_desc near d_desc =
2061 {dyn_dtree, static_dtree, extra_dbits, 0, D_CODES, MAX_BITS, 0};
2063 local tree_desc near bl_desc =
2064 {bl_tree, (ct_data near *)0, extra_blbits, 0, BL_CODES, MAX_BL_BITS, 0};
2067 local ush near bl_count[MAX_BITS+1];
2068 /* number of codes at each bit length for an optimal tree */
2070 local uch near bl_order[BL_CODES]
2071 = {16,17,18,0,8,7,9,6,10,5,11,4,12,3,13,2,14,1,15};
2072 /* The lengths of the bit length codes are sent in order of decreasing
2073 * probability, to avoid transmitting the lengths for unused bit length codes.
2076 local int near heap[2*L_CODES+1]; /* heap used to build the Huffman trees */
2077 local int heap_len; /* number of elements in the heap */
2078 local int heap_max; /* element of largest frequency */
2079 /* The sons of heap[n] are heap[2*n] and heap[2*n+1]. heap[0] is not used.
2080 * The same heap array is used to build all trees.
2083 local uch near depth[2*L_CODES+1];
2084 /* Depth of each subtree used as tie breaker for trees of equal frequency */
2086 local uch length_code[MAX_MATCH-MIN_MATCH+1];
2087 /* length code for each normalized match length (0 == MIN_MATCH) */
2089 local uch dist_code[512];
2090 /* distance codes. The first 256 values correspond to the distances
2091 * 3 .. 258, the last 256 values correspond to the top 8 bits of
2092 * the 15 bit distances.
2095 local int near base_length[LENGTH_CODES];
2096 /* First normalized length for each code (0 = MIN_MATCH) */
2098 local int near base_dist[D_CODES];
2099 /* First normalized distance for each code (0 = distance of 1) */
2102 /* DECLARE(uch, l_buf, LIT_BUFSIZE); buffer for literals or lengths */
2104 /* DECLARE(ush, d_buf, DIST_BUFSIZE); buffer for distances */
2106 local uch near flag_buf[(LIT_BUFSIZE/8)];
2107 /* flag_buf is a bit array distinguishing literals from lengths in
2108 * l_buf, thus indicating the presence or absence of a distance.
2111 local unsigned last_lit; /* running index in l_buf */
2112 local unsigned last_dist; /* running index in d_buf */
2113 local unsigned last_flags; /* running index in flag_buf */
2114 local uch flags; /* current flags not yet saved in flag_buf */
2115 local uch flag_bit; /* current bit used in flags */
2116 /* bits are filled in flags starting at bit 0 (least significant).
2117 * Note: these flags are overkill in the current code since we don't
2118 * take advantage of DIST_BUFSIZE == LIT_BUFSIZE.
2121 local ulg opt_len; /* bit length of current block with optimal trees */
2122 local ulg static_len; /* bit length of current block with static trees */
2124 local ulg compressed_len; /* total bit length of compressed file */
2126 local ulg input_len; /* total byte length of input file */
2127 /* input_len is for debugging only since we can get it by other means. */
2129 ush *file_type; /* pointer to UNKNOWN, BINARY or ASCII */
2130 int *file_method; /* pointer to DEFLATE or STORE */
2133 extern ulg bits_sent; /* bit length of the compressed data */
2134 extern long isize; /* byte length of input file */
2137 extern long block_start; /* window offset of current block */
2138 extern unsigned near strstart; /* window offset of current string */
2140 /* ===========================================================================
2141 * Local (static) routines in this file.
2144 local void init_block OF((void));
2145 local void pqdownheap OF((ct_data near *tree, int k));
2146 local void gen_bitlen OF((tree_desc near *desc));
2147 local void gen_codes OF((ct_data near *tree, int max_code));
2148 local void build_tree OF((tree_desc near *desc));
2149 local void scan_tree OF((ct_data near *tree, int max_code));
2150 local void send_tree OF((ct_data near *tree, int max_code));
2151 local int build_bl_tree OF((void));
2152 local void send_all_trees OF((int lcodes, int dcodes, int blcodes));
2153 local void compress_block OF((ct_data near *ltree, ct_data near *dtree));
2154 local void set_file_type OF((void));
2158 # define send_code(c, tree) send_bits(tree[c].Code, tree[c].Len)
2159 /* Send a code of the given tree. c and tree must not have side effects */
2162 # define send_code(c, tree) \
2163 { if (verbose>1) fprintf(stderr,"\ncd %3d ",(c)); \
2164 send_bits(tree[c].Code, tree[c].Len); }
2167 #define d_code(dist) \
2168 ((dist) < 256 ? dist_code[dist] : dist_code[256+((dist)>>7)])
2169 /* Mapping from a distance to a distance code. dist is the distance - 1 and
2170 * must not have side effects. dist_code[256] and dist_code[257] are never
2174 #define MAX(a,b) (a >= b ? a : b)
2175 /* the arguments must not have side effects */
2177 /* ===========================================================================
2178 * Allocate the match buffer, initialize the various tables and save the
2179 * location of the internal file attribute (ascii/binary) and method
2182 void ct_init(attr, methodp)
2183 ush *attr; /* pointer to internal file attribute */
2184 int *methodp; /* pointer to compression method */
2186 int n; /* iterates over tree elements */
2187 int bits; /* bit counter */
2188 int length; /* length value */
2189 int code; /* code value */
2190 int dist; /* distance index */
2193 file_method = methodp;
2194 compressed_len = input_len = 0L;
2196 if (static_dtree[0].Len != 0) return; /* ct_init already called */
2198 /* Initialize the mapping length (0..255) -> length code (0..28) */
2200 for (code = 0; code < LENGTH_CODES-1; code++) {
2201 base_length[code] = length;
2202 for (n = 0; n < (1<<extra_lbits[code]); n++) {
2203 length_code[length++] = (uch)code;
2206 Assert (length == 256, "ct_init: length != 256");
2207 /* Note that the length 255 (match length 258) can be represented
2208 * in two different ways: code 284 + 5 bits or code 285, so we
2209 * overwrite length_code[255] to use the best encoding:
2211 length_code[length-1] = (uch)code;
2213 /* Initialize the mapping dist (0..32K) -> dist code (0..29) */
2215 for (code = 0 ; code < 16; code++) {
2216 base_dist[code] = dist;
2217 for (n = 0; n < (1<<extra_dbits[code]); n++) {
2218 dist_code[dist++] = (uch)code;
2221 Assert (dist == 256, "ct_init: dist != 256");
2222 dist >>= 7; /* from now on, all distances are divided by 128 */
2223 for ( ; code < D_CODES; code++) {
2224 base_dist[code] = dist << 7;
2225 for (n = 0; n < (1<<(extra_dbits[code]-7)); n++) {
2226 dist_code[256 + dist++] = (uch)code;
2229 Assert (dist == 256, "ct_init: 256+dist != 512");
2231 /* Construct the codes of the static literal tree */
2232 for (bits = 0; bits <= MAX_BITS; bits++) bl_count[bits] = 0;
2234 while (n <= 143) static_ltree[n++].Len = 8, bl_count[8]++;
2235 while (n <= 255) static_ltree[n++].Len = 9, bl_count[9]++;
2236 while (n <= 279) static_ltree[n++].Len = 7, bl_count[7]++;
2237 while (n <= 287) static_ltree[n++].Len = 8, bl_count[8]++;
2238 /* Codes 286 and 287 do not exist, but we must include them in the
2239 * tree construction to get a canonical Huffman tree (longest code
2242 gen_codes((ct_data near *)static_ltree, L_CODES+1);
2244 /* The static distance tree is trivial: */
2245 for (n = 0; n < D_CODES; n++) {
2246 static_dtree[n].Len = 5;
2247 static_dtree[n].Code = bi_reverse(n, 5);
2250 /* Initialize the first block of the first file: */
2254 /* ===========================================================================
2255 * Initialize a new block.
2257 local void init_block()
2259 int n; /* iterates over tree elements */
2261 /* Initialize the trees. */
2262 for (n = 0; n < L_CODES; n++) dyn_ltree[n].Freq = 0;
2263 for (n = 0; n < D_CODES; n++) dyn_dtree[n].Freq = 0;
2264 for (n = 0; n < BL_CODES; n++) bl_tree[n].Freq = 0;
2266 dyn_ltree[END_BLOCK].Freq = 1;
2267 opt_len = static_len = 0L;
2268 last_lit = last_dist = last_flags = 0;
2269 flags = 0; flag_bit = 1;
2273 /* Index within the heap array of least frequent node in the Huffman tree */
2276 /* ===========================================================================
2277 * Remove the smallest element from the heap and recreate the heap with
2278 * one less element. Updates heap and heap_len.
2280 #define pqremove(tree, top) \
2282 top = heap[SMALLEST]; \
2283 heap[SMALLEST] = heap[heap_len--]; \
2284 pqdownheap(tree, SMALLEST); \
2287 /* ===========================================================================
2288 * Compares to subtrees, using the tree depth as tie breaker when
2289 * the subtrees have equal frequency. This minimizes the worst case length.
2291 #define smaller(tree, n, m) \
2292 (tree[n].Freq < tree[m].Freq || \
2293 (tree[n].Freq == tree[m].Freq && depth[n] <= depth[m]))
2295 /* ===========================================================================
2296 * Restore the heap property by moving down the tree starting at node k,
2297 * exchanging a node with the smallest of its two sons if necessary, stopping
2298 * when the heap property is re-established (each father smaller than its
2301 local void pqdownheap(tree, k)
2302 ct_data near *tree; /* the tree to restore */
2303 int k; /* node to move down */
2306 int j = k << 1; /* left son of k */
2307 while (j <= heap_len) {
2308 /* Set j to the smallest of the two sons: */
2309 if (j < heap_len && smaller(tree, heap[j+1], heap[j])) j++;
2311 /* Exit if v is smaller than both sons */
2312 if (smaller(tree, v, heap[j])) break;
2314 /* Exchange v with the smallest son */
2315 heap[k] = heap[j]; k = j;
2317 /* And continue down the tree, setting j to the left son of k */
2323 /* ===========================================================================
2324 * Compute the optimal bit lengths for a tree and update the total bit length
2325 * for the current block.
2326 * IN assertion: the fields freq and dad are set, heap[heap_max] and
2327 * above are the tree nodes sorted by increasing frequency.
2328 * OUT assertions: the field len is set to the optimal bit length, the
2329 * array bl_count contains the frequencies for each bit length.
2330 * The length opt_len is updated; static_len is also updated if stree is
2333 local void gen_bitlen(desc)
2334 tree_desc near *desc; /* the tree descriptor */
2336 ct_data near *tree = desc->dyn_tree;
2337 int near *extra = desc->extra_bits;
2338 int base = desc->extra_base;
2339 int max_code = desc->max_code;
2340 int max_length = desc->max_length;
2341 ct_data near *stree = desc->static_tree;
2342 int h; /* heap index */
2343 int n, m; /* iterate over the tree elements */
2344 int bits; /* bit length */
2345 int xbits; /* extra bits */
2346 ush f; /* frequency */
2347 int overflow = 0; /* number of elements with bit length too large */
2349 for (bits = 0; bits <= MAX_BITS; bits++) bl_count[bits] = 0;
2351 /* In a first pass, compute the optimal bit lengths (which may
2352 * overflow in the case of the bit length tree).
2354 tree[heap[heap_max]].Len = 0; /* root of the heap */
2356 for (h = heap_max+1; h < HEAP_SIZE; h++) {
2358 bits = tree[tree[n].Dad].Len + 1;
2359 if (bits > max_length) bits = max_length, overflow++;
2360 tree[n].Len = (ush)bits;
2361 /* We overwrite tree[n].Dad which is no longer needed */
2363 if (n > max_code) continue; /* not a leaf node */
2367 if (n >= base) xbits = extra[n-base];
2369 opt_len += (ulg)f * (bits + xbits);
2370 if (stree) static_len += (ulg)f * (stree[n].Len + xbits);
2372 if (overflow == 0) return;
2374 Trace((stderr,"\nbit length overflow\n"));
2375 /* This happens for example on obj2 and pic of the Calgary corpus */
2377 /* Find the first bit length which could increase: */
2379 bits = max_length-1;
2380 while (bl_count[bits] == 0) bits--;
2381 bl_count[bits]--; /* move one leaf down the tree */
2382 bl_count[bits+1] += 2; /* move one overflow item as its brother */
2383 bl_count[max_length]--;
2384 /* The brother of the overflow item also moves one step up,
2385 * but this does not affect bl_count[max_length]
2388 } while (overflow > 0);
2390 /* Now recompute all bit lengths, scanning in increasing frequency.
2391 * h is still equal to HEAP_SIZE. (It is simpler to reconstruct all
2392 * lengths instead of fixing only the wrong ones. This idea is taken
2393 * from 'ar' written by Haruhiko Okumura.)
2395 for (bits = max_length; bits != 0; bits--) {
2399 if (m > max_code) continue;
2400 if (tree[m].Len != (unsigned) bits) {
2401 Trace((stderr,"code %d bits %d->%d\n", m, tree[m].Len, bits));
2402 opt_len += ((long)bits-(long)tree[m].Len)*(long)tree[m].Freq;
2403 tree[m].Len = (ush)bits;
2410 /* ===========================================================================
2411 * Generate the codes for a given tree and bit counts (which need not be
2413 * IN assertion: the array bl_count contains the bit length statistics for
2414 * the given tree and the field len is set for all tree elements.
2415 * OUT assertion: the field code is set for all tree elements of non
2418 local void gen_codes (tree, max_code)
2419 ct_data near *tree; /* the tree to decorate */
2420 int max_code; /* largest code with non zero frequency */
2422 ush next_code[MAX_BITS+1]; /* next code value for each bit length */
2423 ush code = 0; /* running code value */
2424 int bits; /* bit index */
2425 int n; /* code index */
2427 /* The distribution counts are first used to generate the code values
2428 * without bit reversal.
2430 for (bits = 1; bits <= MAX_BITS; bits++) {
2431 next_code[bits] = code = (code + bl_count[bits-1]) << 1;
2433 /* Check that the bit counts in bl_count are consistent. The last code
2436 Assert (code + bl_count[MAX_BITS]-1 == (1<<MAX_BITS)-1,
2437 "inconsistent bit counts");
2438 Tracev((stderr,"\ngen_codes: max_code %d ", max_code));
2440 for (n = 0; n <= max_code; n++) {
2441 int len = tree[n].Len;
2442 if (len == 0) continue;
2443 /* Now reverse the bits */
2444 tree[n].Code = bi_reverse(next_code[len]++, len);
2446 Tracec(tree != static_ltree, (stderr,"\nn %3d %c l %2d c %4x (%x) ",
2447 n, (isgraph(n) ? n : ' '), len, tree[n].Code, next_code[len]-1));
2451 /* ===========================================================================
2452 * Construct one Huffman tree and assigns the code bit strings and lengths.
2453 * Update the total bit length for the current block.
2454 * IN assertion: the field freq is set for all tree elements.
2455 * OUT assertions: the fields len and code are set to the optimal bit length
2456 * and corresponding code. The length opt_len is updated; static_len is
2457 * also updated if stree is not null. The field max_code is set.
2459 local void build_tree(desc)
2460 tree_desc near *desc; /* the tree descriptor */
2462 ct_data near *tree = desc->dyn_tree;
2463 ct_data near *stree = desc->static_tree;
2464 int elems = desc->elems;
2465 int n, m; /* iterate over heap elements */
2466 int max_code = -1; /* largest code with non zero frequency */
2467 int node = elems; /* next internal node of the tree */
2469 /* Construct the initial heap, with least frequent element in
2470 * heap[SMALLEST]. The sons of heap[n] are heap[2*n] and heap[2*n+1].
2471 * heap[0] is not used.
2473 heap_len = 0, heap_max = HEAP_SIZE;
2475 for (n = 0; n < elems; n++) {
2476 if (tree[n].Freq != 0) {
2477 heap[++heap_len] = max_code = n;
2484 /* The pkzip format requires that at least one distance code exists,
2485 * and that at least one bit should be sent even if there is only one
2486 * possible code. So to avoid special checks later on we force at least
2487 * two codes of non zero frequency.
2489 while (heap_len < 2) {
2490 int new = heap[++heap_len] = (max_code < 2 ? ++max_code : 0);
2493 opt_len--; if (stree) static_len -= stree[new].Len;
2494 /* new is 0 or 1 so it does not have extra bits */
2496 desc->max_code = max_code;
2498 /* The elements heap[heap_len/2+1 .. heap_len] are leaves of the tree,
2499 * establish sub-heaps of increasing lengths:
2501 for (n = heap_len/2; n >= 1; n--) pqdownheap(tree, n);
2503 /* Construct the Huffman tree by repeatedly combining the least two
2507 pqremove(tree, n); /* n = node of least frequency */
2508 m = heap[SMALLEST]; /* m = node of next least frequency */
2510 heap[--heap_max] = n; /* keep the nodes sorted by frequency */
2511 heap[--heap_max] = m;
2513 /* Create a new node father of n and m */
2514 tree[node].Freq = tree[n].Freq + tree[m].Freq;
2515 depth[node] = (uch) (MAX(depth[n], depth[m]) + 1);
2516 tree[n].Dad = tree[m].Dad = (ush)node;
2518 if (tree == bl_tree) {
2519 fprintf(stderr,"\nnode %d(%d), sons %d(%d) %d(%d)",
2520 node, tree[node].Freq, n, tree[n].Freq, m, tree[m].Freq);
2523 /* and insert the new node in the heap */
2524 heap[SMALLEST] = node++;
2525 pqdownheap(tree, SMALLEST);
2527 } while (heap_len >= 2);
2529 heap[--heap_max] = heap[SMALLEST];
2531 /* At this point, the fields freq and dad are set. We can now
2532 * generate the bit lengths.
2534 gen_bitlen((tree_desc near *)desc);
2536 /* The field len is now set, we can generate the bit codes */
2537 gen_codes ((ct_data near *)tree, max_code);
2540 /* ===========================================================================
2541 * Scan a literal or distance tree to determine the frequencies of the codes
2542 * in the bit length tree. Updates opt_len to take into account the repeat
2543 * counts. (The contribution of the bit length codes will be added later
2544 * during the construction of bl_tree.)
2546 local void scan_tree (tree, max_code)
2547 ct_data near *tree; /* the tree to be scanned */
2548 int max_code; /* and its largest code of non zero frequency */
2550 int n; /* iterates over all tree elements */
2551 int prevlen = -1; /* last emitted length */
2552 int curlen; /* length of current code */
2553 int nextlen = tree[0].Len; /* length of next code */
2554 int count = 0; /* repeat count of the current code */
2555 int max_count = 7; /* max repeat count */
2556 int min_count = 4; /* min repeat count */
2558 if (nextlen == 0) max_count = 138, min_count = 3;
2559 tree[max_code+1].Len = (ush)0xffff; /* guard */
2561 for (n = 0; n <= max_code; n++) {
2562 curlen = nextlen; nextlen = tree[n+1].Len;
2563 if (++count < max_count && curlen == nextlen) {
2565 } else if (count < min_count) {
2566 bl_tree[curlen].Freq += count;
2567 } else if (curlen != 0) {
2568 if (curlen != prevlen) bl_tree[curlen].Freq++;
2569 bl_tree[REP_3_6].Freq++;
2570 } else if (count <= 10) {
2571 bl_tree[REPZ_3_10].Freq++;
2573 bl_tree[REPZ_11_138].Freq++;
2575 count = 0; prevlen = curlen;
2577 max_count = 138, min_count = 3;
2578 } else if (curlen == nextlen) {
2579 max_count = 6, min_count = 3;
2581 max_count = 7, min_count = 4;
2586 /* ===========================================================================
2587 * Send a literal or distance tree in compressed form, using the codes in
2590 local void send_tree (tree, max_code)
2591 ct_data near *tree; /* the tree to be scanned */
2592 int max_code; /* and its largest code of non zero frequency */
2594 int n; /* iterates over all tree elements */
2595 int prevlen = -1; /* last emitted length */
2596 int curlen; /* length of current code */
2597 int nextlen = tree[0].Len; /* length of next code */
2598 int count = 0; /* repeat count of the current code */
2599 int max_count = 7; /* max repeat count */
2600 int min_count = 4; /* min repeat count */
2602 /* tree[max_code+1].Len = -1; */ /* guard already set */
2603 if (nextlen == 0) max_count = 138, min_count = 3;
2605 for (n = 0; n <= max_code; n++) {
2606 curlen = nextlen; nextlen = tree[n+1].Len;
2607 if (++count < max_count && curlen == nextlen) {
2609 } else if (count < min_count) {
2610 do { send_code(curlen, bl_tree); } while (--count != 0);
2612 } else if (curlen != 0) {
2613 if (curlen != prevlen) {
2614 send_code(curlen, bl_tree); count--;
2616 Assert(count >= 3 && count <= 6, " 3_6?");
2617 send_code(REP_3_6, bl_tree); send_bits(count-3, 2);
2619 } else if (count <= 10) {
2620 send_code(REPZ_3_10, bl_tree); send_bits(count-3, 3);
2623 send_code(REPZ_11_138, bl_tree); send_bits(count-11, 7);
2625 count = 0; prevlen = curlen;
2627 max_count = 138, min_count = 3;
2628 } else if (curlen == nextlen) {
2629 max_count = 6, min_count = 3;
2631 max_count = 7, min_count = 4;
2636 /* ===========================================================================
2637 * Construct the Huffman tree for the bit lengths and return the index in
2638 * bl_order of the last bit length code to send.
2640 local int build_bl_tree()
2642 int max_blindex; /* index of last bit length code of non zero freq */
2644 /* Determine the bit length frequencies for literal and distance trees */
2645 scan_tree((ct_data near *)dyn_ltree, l_desc.max_code);
2646 scan_tree((ct_data near *)dyn_dtree, d_desc.max_code);
2648 /* Build the bit length tree: */
2649 build_tree((tree_desc near *)(&bl_desc));
2650 /* opt_len now includes the length of the tree representations, except
2651 * the lengths of the bit lengths codes and the 5+5+4 bits for the counts.
2654 /* Determine the number of bit length codes to send. The pkzip format
2655 * requires that at least 4 bit length codes be sent. (appnote.txt says
2656 * 3 but the actual value used is 4.)
2658 for (max_blindex = BL_CODES-1; max_blindex >= 3; max_blindex--) {
2659 if (bl_tree[bl_order[max_blindex]].Len != 0) break;
2661 /* Update opt_len to include the bit length tree and counts */
2662 opt_len += 3*(max_blindex+1) + 5+5+4;
2663 Tracev((stderr, "\ndyn trees: dyn %ld, stat %ld", opt_len, static_len));
2668 /* ===========================================================================
2669 * Send the header for a block using dynamic Huffman trees: the counts, the
2670 * lengths of the bit length codes, the literal tree and the distance tree.
2671 * IN assertion: lcodes >= 257, dcodes >= 1, blcodes >= 4.
2673 local void send_all_trees(lcodes, dcodes, blcodes)
2674 int lcodes, dcodes, blcodes; /* number of codes for each tree */
2676 int rank; /* index in bl_order */
2678 Assert (lcodes >= 257 && dcodes >= 1 && blcodes >= 4, "not enough codes");
2679 Assert (lcodes <= L_CODES && dcodes <= D_CODES && blcodes <= BL_CODES,
2681 Tracev((stderr, "\nbl counts: "));
2682 send_bits(lcodes-257, 5); /* not +255 as stated in appnote.txt */
2683 send_bits(dcodes-1, 5);
2684 send_bits(blcodes-4, 4); /* not -3 as stated in appnote.txt */
2685 for (rank = 0; rank < blcodes; rank++) {
2686 Tracev((stderr, "\nbl code %2d ", bl_order[rank]));
2687 send_bits(bl_tree[bl_order[rank]].Len, 3);
2689 Tracev((stderr, "\nbl tree: sent %ld", bits_sent));
2691 send_tree((ct_data near *)dyn_ltree, lcodes-1); /* send the literal tree */
2692 Tracev((stderr, "\nlit tree: sent %ld", bits_sent));
2694 send_tree((ct_data near *)dyn_dtree, dcodes-1); /* send the distance tree */
2695 Tracev((stderr, "\ndist tree: sent %ld", bits_sent));
2698 /* ===========================================================================
2699 * Determine the best encoding for the current block: dynamic trees, static
2700 * trees or store, and output the encoded block to the zip file. This function
2701 * returns the total compressed length for the file so far.
2703 ulg flush_block(buf, stored_len, eof)
2704 char *buf; /* input block, or NULL if too old */
2705 ulg stored_len; /* length of input block */
2706 int eof; /* true if this is the last block for a file */
2708 ulg opt_lenb, static_lenb; /* opt_len and static_len in bytes */
2709 int max_blindex; /* index of last bit length code of non zero freq */
2711 flag_buf[last_flags] = flags; /* Save the flags for the last 8 items */
2713 /* Check if the file is ascii or binary */
2714 if (*file_type == (ush)UNKNOWN) set_file_type();
2716 /* Construct the literal and distance trees */
2717 build_tree((tree_desc near *)(&l_desc));
2718 Tracev((stderr, "\nlit data: dyn %ld, stat %ld", opt_len, static_len));
2720 build_tree((tree_desc near *)(&d_desc));
2721 Tracev((stderr, "\ndist data: dyn %ld, stat %ld", opt_len, static_len));
2722 /* At this point, opt_len and static_len are the total bit lengths of
2723 * the compressed block data, excluding the tree representations.
2726 /* Build the bit length tree for the above two trees, and get the index
2727 * in bl_order of the last bit length code to send.
2729 max_blindex = build_bl_tree();
2731 /* Determine the best encoding. Compute first the block length in bytes */
2732 opt_lenb = (opt_len+3+7)>>3;
2733 static_lenb = (static_len+3+7)>>3;
2734 input_len += stored_len; /* for debugging only */
2736 Trace((stderr, "\nopt %lu(%lu) stat %lu(%lu) stored %lu lit %u dist %u ",
2737 opt_lenb, opt_len, static_lenb, static_len, stored_len,
2738 last_lit, last_dist));
2740 if (static_lenb <= opt_lenb) opt_lenb = static_lenb;
2742 /* If compression failed and this is the first and last block,
2743 * and if the zip file can be seeked (to rewrite the local header),
2744 * the whole file is transformed into a stored file:
2748 if (stored_len <= opt_lenb && eof && compressed_len == 0L && seekable()) {
2750 /* Since LIT_BUFSIZE <= 2*WSIZE, the input data must be there: */
2751 if (buf == (char*)0) error ("block vanished");
2753 copy_block(buf, (unsigned)stored_len, 0); /* without header */
2754 compressed_len = stored_len << 3;
2755 *file_method = STORED;
2759 } else if (stored_len+4 <= opt_lenb && buf != (char*)0) {
2760 /* 4: two words for the lengths */
2762 /* The test buf != NULL is only necessary if LIT_BUFSIZE > WSIZE.
2763 * Otherwise we can't have processed more than WSIZE input bytes since
2764 * the last block flush, because compression would have been
2765 * successful. If LIT_BUFSIZE <= WSIZE, it is never too late to
2766 * transform a block into a stored block.
2768 send_bits((STORED_BLOCK<<1)+eof, 3); /* send block type */
2769 compressed_len = (compressed_len + 3 + 7) & ~7L;
2770 compressed_len += (stored_len + 4) << 3;
2772 copy_block(buf, (unsigned)stored_len, 1); /* with header */
2776 } else if (static_lenb == opt_lenb) {
2778 send_bits((STATIC_TREES<<1)+eof, 3);
2779 compress_block((ct_data near *)static_ltree, (ct_data near *)static_dtree);
2780 compressed_len += 3 + static_len;
2782 send_bits((DYN_TREES<<1)+eof, 3);
2783 send_all_trees(l_desc.max_code+1, d_desc.max_code+1, max_blindex+1);
2784 compress_block((ct_data near *)dyn_ltree, (ct_data near *)dyn_dtree);
2785 compressed_len += 3 + opt_len;
2787 Assert (compressed_len == bits_sent, "bad compressed size");
2791 Assert (input_len == isize, "bad input size");
2793 compressed_len += 7; /* align on byte boundary */
2795 Tracev((stderr,"\ncomprlen %lu(%lu) ", compressed_len>>3,
2796 compressed_len-7*eof));
2798 return compressed_len >> 3;
2801 /* ===========================================================================
2802 * Save the match info and tally the frequency counts. Return true if
2803 * the current block must be flushed.
2805 int ct_tally (dist, lc)
2806 int dist; /* distance of matched string */
2807 int lc; /* match length-MIN_MATCH or unmatched char (if dist==0) */
2809 l_buf[last_lit++] = (uch)lc;
2811 /* lc is the unmatched char */
2812 dyn_ltree[lc].Freq++;
2814 /* Here, lc is the match length - MIN_MATCH */
2815 dist--; /* dist = match distance - 1 */
2816 Assert((ush)dist < (ush)MAX_DIST &&
2817 (ush)lc <= (ush)(MAX_MATCH-MIN_MATCH) &&
2818 (ush)d_code(dist) < (ush)D_CODES, "ct_tally: bad match");
2820 dyn_ltree[length_code[lc]+LITERALS+1].Freq++;
2821 dyn_dtree[d_code(dist)].Freq++;
2823 d_buf[last_dist++] = (ush)dist;
2828 /* Output the flags if they fill a byte: */
2829 if ((last_lit & 7) == 0) {
2830 flag_buf[last_flags++] = flags;
2831 flags = 0, flag_bit = 1;
2833 /* Try to guess if it is profitable to stop the current block here */
2834 if ((last_lit & 0xfff) == 0) {
2835 /* Compute an upper bound for the compressed length */
2836 ulg out_length = (ulg)last_lit*8L;
2837 ulg in_length = (ulg)strstart-block_start;
2839 for (dcode = 0; dcode < D_CODES; dcode++) {
2840 out_length += (ulg)dyn_dtree[dcode].Freq*(5L+extra_dbits[dcode]);
2843 Trace((stderr,"\nlast_lit %u, last_dist %u, in %ld, out ~%ld(%ld%%) ",
2844 last_lit, last_dist, in_length, out_length,
2845 100L - out_length*100L/in_length));
2846 if (last_dist < last_lit/2 && out_length < in_length/2) return 1;
2848 return (last_lit == LIT_BUFSIZE-1 || last_dist == DIST_BUFSIZE);
2849 /* We avoid equality with LIT_BUFSIZE because of wraparound at 64K
2850 * on 16 bit machines and because stored blocks are restricted to
2855 /* ===========================================================================
2856 * Send the block data compressed using the given Huffman trees
2858 local void compress_block(ltree, dtree)
2859 ct_data near *ltree; /* literal tree */
2860 ct_data near *dtree; /* distance tree */
2862 unsigned dist; /* distance of matched string */
2863 int lc; /* match length or unmatched char (if dist == 0) */
2864 unsigned lx = 0; /* running index in l_buf */
2865 unsigned dx = 0; /* running index in d_buf */
2866 unsigned fx = 0; /* running index in flag_buf */
2867 uch flag = 0; /* current flags */
2868 unsigned code; /* the code to send */
2869 int extra; /* number of extra bits to send */
2871 if (last_lit != 0) do {
2872 if ((lx & 7) == 0) flag = flag_buf[fx++];
2874 if ((flag & 1) == 0) {
2875 send_code(lc, ltree); /* send a literal byte */
2876 Tracecv(isgraph(lc), (stderr," '%c' ", lc));
2878 /* Here, lc is the match length - MIN_MATCH */
2879 code = length_code[lc];
2880 send_code(code+LITERALS+1, ltree); /* send the length code */
2881 extra = extra_lbits[code];
2883 lc -= base_length[code];
2884 send_bits(lc, extra); /* send the extra length bits */
2887 /* Here, dist is the match distance - 1 */
2888 code = d_code(dist);
2889 Assert (code < D_CODES, "bad d_code");
2891 send_code(code, dtree); /* send the distance code */
2892 extra = extra_dbits[code];
2894 dist -= base_dist[code];
2895 send_bits(dist, extra); /* send the extra distance bits */
2897 } /* literal or match pair ? */
2899 } while (lx < last_lit);
2901 send_code(END_BLOCK, ltree);
2904 /* ===========================================================================
2905 * Set the file type to ASCII or BINARY, using a crude approximation:
2906 * binary if more than 20% of the bytes are <= 6 or >= 128, ascii otherwise.
2907 * IN assertion: the fields freq of dyn_ltree are set and the total of all
2908 * frequencies does not exceed 64K (to fit in an int on 16 bit machines).
2910 local void set_file_type()
2913 unsigned ascii_freq = 0;
2914 unsigned bin_freq = 0;
2915 while (n < 7) bin_freq += dyn_ltree[n++].Freq;
2916 while (n < 128) ascii_freq += dyn_ltree[n++].Freq;
2917 while (n < LITERALS) bin_freq += dyn_ltree[n++].Freq;
2918 *file_type = bin_freq > (ascii_freq >> 2) ? BINARY : ASCII;
2919 if (*file_type == BINARY && translate_eol) {
2920 warn("-l used on binary file", "");
2923 /* util.c -- utility functions for gzip support
2924 * Copyright (C) 1992-1993 Jean-loup Gailly
2925 * This is free software; you can redistribute it and/or modify it under the
2926 * terms of the GNU General Public License, see the file COPYING.
2931 #include <sys/types.h>
2933 #ifdef HAVE_UNISTD_H
2934 # include <unistd.h>
2940 #if defined(STDC_HEADERS) || !defined(NO_STDLIB_H)
2941 # include <stdlib.h>
2946 extern ulg crc_32_tab[]; /* crc table, defined below */
2948 /* ===========================================================================
2949 * Copy input to output unchanged: zcat == cat with --force.
2950 * IN assertion: insize bytes have already been read in inbuf.
2953 int in, out; /* input and output file descriptors */
2956 while (insize != 0 && (int)insize != EOF) {
2957 write_buf(out, (char*)inbuf, insize);
2958 bytes_out += insize;
2959 insize = read(in, (char*)inbuf, INBUFSIZ);
2961 if ((int)insize == EOF && errno != 0) {
2964 bytes_in = bytes_out;
2968 /* ========================================================================
2969 * Put string s in lower case, return s.
2975 for (t = s; *t; t++) *t = tolow(*t);
2979 #if defined(NO_STRING_H) && !defined(STDC_HEADERS)
2981 /* Provide missing strspn and strcspn functions. */
2987 int strspn OF((const char *s, const char *accept));
2988 int strcspn OF((const char *s, const char *reject));
2990 /* ========================================================================
2991 * Return the length of the maximum initial segment
2992 * of s which contains only characters in accept.
2994 int strspn(s, accept)
2998 register const char *p;
2999 register const char *a;
3000 register int count = 0;
3002 for (p = s; *p != '\0'; ++p) {
3003 for (a = accept; *a != '\0'; ++a) {
3004 if (*p == *a) break;
3006 if (*a == '\0') return count;
3012 /* ========================================================================
3013 * Return the length of the maximum inital segment of s
3014 * which contains no characters from reject.
3016 int strcspn(s, reject)
3020 register int count = 0;
3022 while (*s != '\0') {
3023 if (strchr(reject, *s++) != NULL) return count;
3029 #endif /* NO_STRING_H */
3031 /* ========================================================================
3032 * Add an environment variable (if any) before argv, and update argc.
3033 * Return the expanded environment variable to be freed later, or NULL
3034 * if no options were added to argv.
3036 #define SEPARATOR " \t" /* separators in env variable */
3038 char *add_envopt(argcp, argvp, env)
3039 int *argcp; /* pointer to argc */
3040 char ***argvp; /* pointer to argv */
3041 char *env; /* name of environment variable */
3043 char *p; /* running pointer through env variable */
3044 char **oargv; /* runs through old argv array */
3045 char **nargv; /* runs through new argv array */
3046 int oargc = *argcp; /* old argc */
3047 int nargc = 0; /* number of arguments in env variable */
3049 env = (char*)getenv(env);
3050 if (env == NULL) return NULL;
3052 p = (char*)xmalloc(strlen(env)+1);
3053 env = strcpy(p, env); /* keep env variable intact */
3055 for (p = env; *p; nargc++ ) { /* move through env */
3056 p += strspn(p, SEPARATOR); /* skip leading separators */
3057 if (*p == '\0') break;
3059 p += strcspn(p, SEPARATOR); /* find end of word */
3060 if (*p) *p++ = '\0'; /* mark it */
3067 /* Allocate the new argv array, with an extra element just in case
3068 * the original arg list did not end with a NULL.
3070 nargv = (char**)calloc(*argcp+1, sizeof(char *));
3071 if (nargv == NULL) error("out of memory");
3075 /* Copy the program name first */
3076 if (oargc-- < 0) error("argc<=0");
3077 *(nargv++) = *(oargv++);
3079 /* Then copy the environment args */
3080 for (p = env; nargc > 0; nargc--) {
3081 p += strspn(p, SEPARATOR); /* skip separators */
3082 *(nargv++) = p; /* store start */
3083 while (*p++) ; /* skip over word */
3086 /* Finally copy the old args and add a NULL (usual convention) */
3087 while (oargc--) *(nargv++) = *(oargv++);
3091 /* ========================================================================
3092 * Display compression ratio on the given stream on 6 characters.
3094 void display_ratio(num, den, file)
3099 long ratio; /* 1000 times the compression ratio */
3102 ratio = 0; /* no compression */
3103 } else if (den < 2147483L) { /* (2**31 -1)/1000 */
3104 ratio = 1000L*num/den;
3106 ratio = num/(den/1000L);
3114 fprintf(file, "%2ld.%1ld%%", ratio / 10L, ratio % 10L);
3118 /* zip.c -- compress files to the gzip or pkzip format
3119 * Copyright (C) 1992-1993 Jean-loup Gailly
3120 * This is free software; you can redistribute it and/or modify it under the
3121 * terms of the GNU General Public License, see the file COPYING.
3125 #include <sys/types.h>
3127 #ifdef HAVE_UNISTD_H
3128 # include <unistd.h>
3134 local ulg crc; /* crc on uncompressed file data */
3135 long header_bytes; /* number of bytes in gzip header */
3137 /* ===========================================================================
3138 * Deflate in to out.
3139 * IN assertions: the input and output buffers are cleared.
3140 * The variables time_stamp and save_orig_name are initialized.
3143 int in, out; /* input and output file descriptors */
3145 uch flags = 0; /* general purpose bit flags */
3146 ush attr = 0; /* ascii/binary flag */
3147 ush deflate_flags = 0; /* pkzip -es, -en or -ex equivalent */
3153 /* Write the header to the gzip file. See algorithm.doc for the format */
3156 put_byte(GZIP_MAGIC[0]); /* magic header */
3157 put_byte(GZIP_MAGIC[1]);
3158 put_byte(DEFLATED); /* compression method */
3160 put_byte(flags); /* general flags */
3161 put_long(time_stamp);
3163 /* Write deflated file to zip file */
3167 ct_init(&attr, &method);
3168 lm_init(&deflate_flags);
3170 put_byte((uch)deflate_flags); /* extra flags */
3171 put_byte(OS_CODE); /* OS identifier */
3173 header_bytes = (long)outcnt;
3177 /* Write the crc and uncompressed size */
3180 header_bytes += 2*sizeof(long);
3187 /* ===========================================================================
3188 * Read a new buffer from the current input file, perform end-of-line
3189 * translation, and update the crc and input file size.
3190 * IN assertion: size >= 2 (for end-of-line translation)
3192 int file_read(buf, size)
3198 Assert(insize == 0, "inbuf not empty");
3200 len = read(ifd, buf, size);
3201 if (len == (unsigned)(-1) || len == 0) return (int)len;
3203 crc = updcrc((uch*)buf, len);