1 /* vi: set sw=4 ts=4: */
2 /* gzip.c -- this is a stripped down version of gzip I put into busybox, it does
3 * only standard in to standard out with -9 compression. It also requires the
4 * zcat module for some important functions.
6 * Charles P. Wright <cpw@unix.asb.com>
12 //#error you need zcat to have gzip support!
15 static const char gzip_usage[] =
16 "gzip [OPTION]... FILE\n\n"
17 "Compress FILE with maximum compression.\n"
18 "When FILE is -, reads standard input. Implies -c.\n\n"
21 "\t-c\tWrite output to standard output instead of FILE.gz\n";
24 /* gzip.h -- common declarations for all gzip modules
25 * Copyright (C) 1992-1993 Jean-loup Gailly.
26 * This is free software; you can redistribute it and/or modify it under the
27 * terms of the GNU General Public License, see the file COPYING.
30 #if defined(__STDC__) || defined(PROTO)
31 # define OF(args) args
42 /* I don't like nested includes, but the string and io functions are used
46 #if !defined(NO_STRING_H) || defined(STDC_HEADERS)
48 # if !defined(STDC_HEADERS) && !defined(NO_MEMORY_H) && !defined(__GNUC__)
51 # define memzero(s, n) memset ((voidp)(s), 0, (n))
55 # define strrchr rindex
56 # define memcpy(d, s, n) bcopy((s), (d), (n))
57 # define memcmp(s1, s2, n) bcmp((s1), (s2), (n))
58 # define memzero(s, n) bzero((s), (n))
62 # define RETSIGTYPE void
67 typedef unsigned char uch;
68 typedef unsigned short ush;
69 typedef unsigned long ulg;
71 /* Return codes from gzip */
76 /* Compression methods (see algorithm.doc) */
81 /* methods 4 to 7 reserved */
84 extern int method; /* compression method */
86 /* To save memory for 16 bit systems, some arrays are overlaid between
87 * the various modules:
88 * deflate: prev+head window d_buf l_buf outbuf
89 * unlzw: tab_prefix tab_suffix stack inbuf outbuf
90 * inflate: window inbuf
91 * unpack: window inbuf prefix_len
92 * unlzh: left+right window c_table inbuf c_len
93 * For compression, input is done in window[]. For decompression, output
94 * is done in window except for unlzw.
99 # define INBUFSIZ 0x2000 /* input buffer size */
101 # define INBUFSIZ 0x8000 /* input buffer size */
104 #define INBUF_EXTRA 64 /* required by unlzw() */
108 # define OUTBUFSIZ 8192 /* output buffer size */
110 # define OUTBUFSIZ 16384 /* output buffer size */
113 #define OUTBUF_EXTRA 2048 /* required by unlzw() */
117 # define DIST_BUFSIZE 0x2000 /* buffer for distances, see trees.c */
119 # define DIST_BUFSIZE 0x8000 /* buffer for distances, see trees.c */
124 # define EXTERN(type, array) extern type * near array
125 # define DECLARE(type, array, size) type * near array
126 # define ALLOC(type, array, size) { \
127 array = (type*)fcalloc((size_t)(((size)+1L)/2), 2*sizeof(type)); \
128 if (array == NULL) error("insufficient memory"); \
130 # define FREE(array) {if (array != NULL) fcfree(array), array=NULL;}
132 # define EXTERN(type, array) extern type array[]
133 # define DECLARE(type, array, size) type array[size]
134 # define ALLOC(type, array, size)
138 EXTERN(uch, inbuf); /* input buffer */
139 EXTERN(uch, outbuf); /* output buffer */
140 EXTERN(ush, d_buf); /* buffer for distances, see trees.c */
141 EXTERN(uch, window); /* Sliding window and suffix table (unlzw) */
142 #define tab_suffix window
144 # define tab_prefix prev /* hash link (see deflate.c) */
145 # define head (prev+WSIZE) /* hash head (see deflate.c) */
146 EXTERN(ush, tab_prefix); /* prefix code (see unlzw.c) */
148 # define tab_prefix0 prev
149 # define head tab_prefix1
150 EXTERN(ush, tab_prefix0); /* prefix for even codes */
151 EXTERN(ush, tab_prefix1); /* prefix for odd codes */
154 extern unsigned insize; /* valid bytes in inbuf */
155 extern unsigned inptr; /* index of next byte to be processed in inbuf */
156 extern unsigned outcnt; /* bytes in output buffer */
158 extern long bytes_in; /* number of input bytes */
159 extern long bytes_out; /* number of output bytes */
160 extern long header_bytes; /* number of bytes in gzip header */
162 #define isize bytes_in
163 /* for compatibility with old zip sources (to be cleaned) */
165 extern int ifd; /* input file descriptor */
166 extern int ofd; /* output file descriptor */
167 extern char ifname[]; /* input file name or "stdin" */
168 extern char ofname[]; /* output file name or "stdout" */
169 extern char *progname; /* program name */
171 extern long time_stamp; /* original time stamp (modification time) */
172 extern long ifile_size; /* input file size, -1 for devices (debug only) */
174 typedef int file_t; /* Do not use stdio */
176 #define NO_FILE (-1) /* in memory compression */
179 #define PACK_MAGIC "\037\036" /* Magic header for packed files */
180 #define GZIP_MAGIC "\037\213" /* Magic header for gzip files, 1F 8B */
181 #define OLD_GZIP_MAGIC "\037\236" /* Magic header for gzip 0.5 = freeze 1.x */
182 #define LZH_MAGIC "\037\240" /* Magic header for SCO LZH Compress files */
183 #define PKZIP_MAGIC "\120\113\003\004" /* Magic header for pkzip files */
186 #define ASCII_FLAG 0x01 /* bit 0 set: file probably ascii text */
187 #define CONTINUATION 0x02 /* bit 1 set: continuation of multi-part gzip file */
188 #define EXTRA_FIELD 0x04 /* bit 2 set: extra field present */
189 #define ORIG_NAME 0x08 /* bit 3 set: original file name present */
190 #define COMMENT 0x10 /* bit 4 set: file comment present */
191 #define ENCRYPTED 0x20 /* bit 5 set: file is encrypted */
192 #define RESERVED 0xC0 /* bit 6,7: reserved */
194 /* internal file attribute */
195 #define UNKNOWN 0xffff
200 # define WSIZE 0x8000 /* window size--must be a power of two, and */
201 #endif /* at least 32K for zip's deflate method */
204 #define MAX_MATCH 258
205 /* The minimum and maximum match lengths */
207 #define MIN_LOOKAHEAD (MAX_MATCH+MIN_MATCH+1)
208 /* Minimum amount of lookahead, except at the end of the input file.
209 * See deflate.c for comments about the MIN_MATCH+1.
212 #define MAX_DIST (WSIZE-MIN_LOOKAHEAD)
213 /* In order to simplify the code, particularly on 16 bit machines, match
214 * distances are limited to MAX_DIST instead of WSIZE.
217 extern int decrypt; /* flag to turn on decryption */
218 extern int exit_code; /* program exit code */
219 extern int verbose; /* be verbose (-v) */
220 extern int quiet; /* be quiet (-q) */
221 extern int test; /* check .z file integrity */
222 extern int save_orig_name; /* set if original name must be saved */
224 #define get_byte() (inptr < insize ? inbuf[inptr++] : fill_inbuf(0))
225 #define try_byte() (inptr < insize ? inbuf[inptr++] : fill_inbuf(1))
227 /* put_byte is used for the compressed output, put_ubyte for the
228 * uncompressed output. However unlzw() uses window for its
229 * suffix table instead of its output buffer, so it does not use put_ubyte
230 * (to be cleaned up).
232 #define put_byte(c) {outbuf[outcnt++]=(uch)(c); if (outcnt==OUTBUFSIZ)\
234 #define put_ubyte(c) {window[outcnt++]=(uch)(c); if (outcnt==WSIZE)\
237 /* Output a 16 bit value, lsb first */
238 #define put_short(w) \
239 { if (outcnt < OUTBUFSIZ-2) { \
240 outbuf[outcnt++] = (uch) ((w) & 0xff); \
241 outbuf[outcnt++] = (uch) ((ush)(w) >> 8); \
243 put_byte((uch)((w) & 0xff)); \
244 put_byte((uch)((ush)(w) >> 8)); \
248 /* Output a 32 bit value to the bit stream, lsb first */
249 #define put_long(n) { \
250 put_short((n) & 0xffff); \
251 put_short(((ulg)(n)) >> 16); \
254 #define seekable() 0 /* force sequential output */
255 #define translate_eol 0 /* no option -a yet */
257 #define tolow(c) (isupper(c) ? (c)-'A'+'a' : (c)) /* force to lower case */
259 /* Macros for getting two-byte and four-byte header values */
260 #define SH(p) ((ush)(uch)((p)[0]) | ((ush)(uch)((p)[1]) << 8))
261 #define LG(p) ((ulg)(SH(p)) | ((ulg)(SH((p)+2)) << 16))
263 /* Diagnostic functions */
265 # define Assert(cond,msg) {if(!(cond)) error(msg);}
266 # define Trace(x) fprintf x
267 # define Tracev(x) {if (verbose) fprintf x ;}
268 # define Tracevv(x) {if (verbose>1) fprintf x ;}
269 # define Tracec(c,x) {if (verbose && (c)) fprintf x ;}
270 # define Tracecv(c,x) {if (verbose>1 && (c)) fprintf x ;}
272 # define Assert(cond,msg)
277 # define Tracecv(c,x)
280 #define WARN(msg) {if (!quiet) fprintf msg ; \
281 if (exit_code == OK) exit_code = WARNING;}
283 #define do_exit(c) exit(c)
287 extern int zip OF((int in, int out));
288 extern int file_read OF((char *buf, unsigned size));
291 extern int unzip OF((int in, int out));
292 extern int check_zipfile OF((int in));
295 extern int unpack OF((int in, int out));
298 extern int unlzh OF((int in, int out));
301 RETSIGTYPE abort_gzip OF((void));
304 void lm_init OF((ush * flags));
305 ulg deflate OF((void));
308 void ct_init OF((ush * attr, int *method));
309 int ct_tally OF((int dist, int lc));
310 ulg flush_block OF((char *buf, ulg stored_len, int eof));
313 void bi_init OF((file_t zipfile));
314 void send_bits OF((int value, int length));
315 unsigned bi_reverse OF((unsigned value, int length));
316 void bi_windup OF((void));
317 void copy_block OF((char *buf, unsigned len, int header));
318 extern int (*read_buf) OF((char *buf, unsigned size));
321 extern int copy OF((int in, int out));
322 extern ulg updcrc OF((uch * s, unsigned n));
323 extern void clear_bufs OF((void));
324 extern int fill_inbuf OF((int eof_ok));
325 extern void flush_outbuf OF((void));
326 extern void flush_window OF((void));
327 extern void write_buf OF((int fd, voidp buf, unsigned cnt));
328 extern char *strlwr OF((char *s));
329 extern char *add_envopt OF((int *argcp, char ***argvp, char *env));
330 extern void error OF((char *m));
331 extern void warn OF((char *a, char *b));
332 extern void read_error OF((void));
333 extern void write_error OF((void));
334 extern void display_ratio OF((long num, long den, FILE * file));
337 extern int inflate OF((void));
339 /* lzw.h -- define the lzw functions.
340 * Copyright (C) 1992-1993 Jean-loup Gailly.
341 * This is free software; you can redistribute it and/or modify it under the
342 * terms of the GNU General Public License, see the file COPYING.
345 #if !defined(OF) && defined(lint)
352 #define INIT_BITS 9 /* Initial number of bits per code */
354 #define BIT_MASK 0x1f /* Mask for 'number of compression bits' */
355 /* Mask 0x20 is reserved to mean a fourth header byte, and 0x40 is free.
356 * It's a pity that old uncompress does not check bit 0x20. That makes
357 * extension of the format actually undesirable because old compress
358 * would just crash on the new format instead of giving a meaningful
359 * error message. It does check the number of bits, but it's more
360 * helpful to say "unsupported format, get a new version" than
361 * "can only handle 16 bits".
364 #define BLOCK_MODE 0x80
365 /* Block compression: if table is full and compression rate is dropping,
366 * clear the dictionary.
369 #define LZW_RESERVED 0x60 /* reserved bits */
371 #define CLEAR 256 /* flush the dictionary */
372 #define FIRST (CLEAR+1) /* first free entry */
374 extern int maxbits; /* max bits per code for LZW */
375 extern int block_mode; /* block compress mode -C compatible with 2.0 */
377 /* revision.h -- define the version number
378 * Copyright (C) 1992-1993 Jean-loup Gailly.
379 * This is free software; you can redistribute it and/or modify it under the
380 * terms of the GNU General Public License, see the file COPYING.
383 #define VERSION "1.2.4"
385 #define REVDATE "18 Aug 93"
387 /* This version does not support compression into old compress format: */
392 /* tailor.h -- target dependent definitions
393 * Copyright (C) 1992-1993 Jean-loup Gailly.
394 * This is free software; you can redistribute it and/or modify it under the
395 * terms of the GNU General Public License, see the file COPYING.
398 /* The target dependent definitions should be defined here only.
399 * The target dependent functions should be defined in tailor.c.
403 #if defined(__MSDOS__) && !defined(MSDOS)
407 #if defined(__OS2__) && !defined(OS2)
411 #if defined(OS2) && defined(MSDOS) /* MS C under OS/2 */
417 /* DJGPP version 1.09+ on MS-DOS.
418 * The DJGPP 1.09 stat() function must be upgraded before gzip will
420 * No need for DIRENT, since <unistd.h> defines POSIX_SOURCE which
434 # define HAVE_SYS_UTIME_H
438 # define PATH_SEP2 '\\'
439 # define PATH_SEP3 ':'
440 # define MAX_PATH_LEN 128
441 # define NO_MULTIPLE_DOTS
442 # define MAX_EXT_CHARS 3
443 # define Z_SUFFIX "z"
446 # define STDC_HEADERS
447 # define NO_SIZE_CHECK
448 # define casemap(c) tolow(c) /* Force file names to lower case */
450 # define OS_CODE 0x00
451 # define SET_BINARY_MODE(fd) setmode(fd, O_BINARY)
452 # if !defined(NO_ASM) && !defined(ASMV)
460 # define PATH_SEP2 '\\'
461 # define PATH_SEP3 ':'
462 # define MAX_PATH_LEN 260
464 # define NO_MULTIPLE_DOTS
465 # define MAX_EXT_CHARS 3
466 # define Z_SUFFIX "z"
467 # define casemap(c) tolow(c)
471 # define STDC_HEADERS
473 # define OS_CODE 0x06
474 # define SET_BINARY_MODE(fd) setmode(fd, O_BINARY)
476 # define HAVE_SYS_UTIME_H
483 # define HAVE_SYS_UTIME_H
486 # define EXPAND(argc,argv) \
487 {_response(&argc, &argv); _wildcard(&argc, &argv);}
496 # define EXPAND(argc,argv) \
497 {response_expand(&argc, &argv);}
501 #ifdef WIN32 /* Windows NT */
502 # define HAVE_SYS_UTIME_H
504 # define PATH_SEP2 '\\'
505 # define PATH_SEP3 ':'
506 # define MAX_PATH_LEN 260
509 # define STDC_HEADERS
510 # define SET_BINARY_MODE(fd) setmode(fd, O_BINARY)
514 # define NO_MULTIPLE_DOTS
515 # define MAX_EXT_CHARS 3
516 # define Z_SUFFIX "z"
517 # define casemap(c) tolow(c) /* Force file names to lower case */
519 # define OS_CODE 0x0b
526 /* Turbo C 2.0 does not accept static allocations of large arrays */
527 void *fcalloc(unsigned items, unsigned size);
528 void fcfree(void *ptr);
531 # define fcalloc(nitems,itemsize) halloc((long)(nitems),(itemsize))
532 # define fcfree(ptr) hfree(ptr)
536 # define fcalloc(items,size) calloc((items),(size))
538 # define fcalloc(items,size) malloc((size_t)(items)*(size_t)(size))
540 # define fcfree(ptr) free(ptr)
543 #if defined(VAXC) || defined(VMS)
544 # define PATH_SEP ']'
545 # define PATH_SEP2 ':'
546 # define SUFFIX_SEP ';'
547 # define NO_MULTIPLE_DOTS
548 # define Z_SUFFIX "-gz"
550 # define casemap(c) tolow(c)
551 # define OS_CODE 0x02
552 # define OPTIONS_VAR "GZIP_OPT"
553 # define STDC_HEADERS
555 # define EXPAND(argc,argv) vms_expand_args(&argc,&argv);
557 # define unlink delete
565 # define PATH_SEP2 ':'
566 # define STDC_HEADERS
567 # define OS_CODE 0x01
571 # define HAVE_UNISTD_H
573 # define NO_STDIN_FSTAT
578 # include <fcntl.h> /* for read() and write() */
579 # define direct dirent
580 extern void _expand_args(int *argc, char ***argv);
582 # define EXPAND(argc,argv) _expand_args(&argc,&argv);
583 # undef O_BINARY /* disable useless --ascii option */
587 #if defined(ATARI) || defined(atarist)
588 # ifndef STDC_HEADERS
589 # define STDC_HEADERS
590 # define HAVE_UNISTD_H
594 # define OS_CODE 0x05
596 # define PATH_SEP2 '\\'
597 # define PATH_SEP3 ':'
598 # define MAX_PATH_LEN 128
599 # define NO_MULTIPLE_DOTS
600 # define MAX_EXT_CHARS 3
601 # define Z_SUFFIX "z"
603 # define casemap(c) tolow(c) /* Force file names to lower case */
609 # define PATH_SEP ':'
612 # define NO_STDIN_FSTAT
615 # define chmod(file, mode) (0)
616 # define OPEN(name, flags, mode) open(name, flags)
617 # define OS_CODE 0x07
619 # define isatty(fd) ((fd) <= 2)
623 #ifdef __50SERIES /* Prime/PRIMOS */
624 # define PATH_SEP '>'
625 # define STDC_HEADERS
630 # define NO_STDIN_FSTAT
631 # define NO_SIZE_CHECK
634 # define casemap(c) tolow(c) /* Force file names to lower case */
635 # define put_char(c) put_byte((c) & 0x7F)
636 # define get_char(c) ascii2pascii(get_byte())
637 # define OS_CODE 0x0F /* temporary, subject to change */
639 # undef SIGTERM /* We don't want a signal handler for SIGTERM */
643 #if defined(pyr) && !defined(NOMEMCPY) /* Pyramid */
644 # define NOMEMCPY /* problem with overlapping copies */
648 # define OS_CODE 0x0a
652 # define NO_ST_INO /* don't rely on inode numbers */
656 /* Common defaults */
659 # define OS_CODE 0x03 /* assume Unix */
663 # define PATH_SEP '/'
667 # define casemap(c) (c)
671 # define OPTIONS_VAR "GZIP"
675 # define Z_SUFFIX ".gz"
679 # define MAX_SUFFIX MAX_EXT_CHARS
681 # define MAX_SUFFIX 30
684 #ifndef MAKE_LEGAL_NAME
685 # ifdef NO_MULTIPLE_DOTS
686 # define MAKE_LEGAL_NAME(name) make_simple_name(name)
688 # define MAKE_LEGAL_NAME(name)
694 /* keep at least MIN_PART chars between dots in a file name. */
698 # define EXPAND(argc,argv)
705 #ifndef SET_BINARY_MODE
706 # define SET_BINARY_MODE(fd)
710 # define OPEN(name, flags, mode) open(name, flags, mode)
714 # define get_char() get_byte()
718 # define put_char(c) put_byte(c)
720 /* bits.c -- output variable-length bit strings
721 * Copyright (C) 1992-1993 Jean-loup Gailly
722 * This is free software; you can redistribute it and/or modify it under the
723 * terms of the GNU General Public License, see the file COPYING.
730 * Output variable-length bit strings. Compression can be done
731 * to a file or to memory. (The latter is not supported in this version.)
735 * The PKZIP "deflate" file format interprets compressed file data
736 * as a sequence of bits. Multi-bit strings in the file may cross
737 * byte boundaries without restriction.
739 * The first bit of each byte is the low-order bit.
741 * The routines in this file allow a variable-length bit value to
742 * be output right-to-left (useful for literal values). For
743 * left-to-right output (useful for code strings from the tree routines),
744 * the bits must have been reversed first with bi_reverse().
746 * For in-memory compression, the compressed bit stream goes directly
747 * into the requested output buffer. The input data is read in blocks
748 * by the mem_read() function. The buffer is limited to 64K on 16 bit
753 * void bi_init (FILE *zipfile)
754 * Initialize the bit string routines.
756 * void send_bits (int value, int length)
757 * Write out a bit string, taking the source bits right to
760 * int bi_reverse (int value, int length)
761 * Reverse the bits of a bit string, taking the source bits left to
762 * right and emitting them right to left.
764 * void bi_windup (void)
765 * Write out any remaining bits in an incomplete byte.
767 * void copy_block(char *buf, unsigned len, int header)
768 * Copy a stored block to the zip file, storing first the length and
769 * its one's complement if requested.
777 /* ===========================================================================
778 * Local data used by the "bit string" routines.
781 local file_t zfile; /* output gzip file */
783 local unsigned short bi_buf;
785 /* Output buffer. bits are inserted starting at the bottom (least significant
789 #define Buf_size (8 * 2*sizeof(char))
790 /* Number of bits used within bi_buf. (bi_buf might be implemented on
791 * more than 16 bits on some systems.)
796 /* Number of valid bits in bi_buf. All bits above the last valid bit
800 int (*read_buf) OF((char *buf, unsigned size));
802 /* Current input function. Set to mem_read for in-memory compression */
805 ulg bits_sent; /* bit length of the compressed data */
808 /* ===========================================================================
809 * Initialize the bit string routines.
811 void bi_init(zipfile)
812 file_t zipfile; /* output zip file, NO_FILE for in-memory compression */
821 /* Set the defaults for file compression. They are set by memcompress
822 * for in-memory compression.
824 if (zfile != NO_FILE) {
825 read_buf = file_read;
829 /* ===========================================================================
830 * Send a value on a given number of bits.
831 * IN assertion: length <= 16 and value fits in length bits.
833 void send_bits(value, length)
834 int value; /* value to send */
835 int length; /* number of bits */
838 Tracev((stderr, " l %2d v %4x ", length, value));
839 Assert(length > 0 && length <= 15, "invalid length");
840 bits_sent += (ulg) length;
842 /* If not enough room in bi_buf, use (valid) bits from bi_buf and
843 * (16 - bi_valid) bits from value, leaving (width - (16-bi_valid))
844 * unused bits in value.
846 if (bi_valid > (int) Buf_size - length) {
847 bi_buf |= (value << bi_valid);
849 bi_buf = (ush) value >> (Buf_size - bi_valid);
850 bi_valid += length - Buf_size;
852 bi_buf |= value << bi_valid;
857 /* ===========================================================================
858 * Reverse the first len bits of a code, using straightforward code (a faster
859 * method would use a table)
860 * IN assertion: 1 <= len <= 15
862 unsigned bi_reverse(code, len)
863 unsigned code; /* the value to invert */
864 int len; /* its bit length */
866 register unsigned res = 0;
870 code >>= 1, res <<= 1;
875 /* ===========================================================================
876 * Write out any remaining bits in an incomplete byte.
882 } else if (bi_valid > 0) {
888 bits_sent = (bits_sent + 7) & ~7;
892 /* ===========================================================================
893 * Copy a stored block to the zip file, storing first the length and its
894 * one's complement if requested.
896 void copy_block(buf, len, header)
897 char *buf; /* the input data */
898 unsigned len; /* its length */
899 int header; /* true if block header must be written */
901 bi_windup(); /* align on byte boundary */
904 put_short((ush) len);
905 put_short((ush) ~ len);
911 bits_sent += (ulg) len << 3;
924 /* deflate.c -- compress data using the deflation algorithm
925 * Copyright (C) 1992-1993 Jean-loup Gailly
926 * This is free software; you can redistribute it and/or modify it under the
927 * terms of the GNU General Public License, see the file COPYING.
933 * Identify new text as repetitions of old text within a fixed-
934 * length sliding window trailing behind the new text.
938 * The "deflation" process depends on being able to identify portions
939 * of the input text which are identical to earlier input (within a
940 * sliding window trailing behind the input currently being processed).
942 * The most straightforward technique turns out to be the fastest for
943 * most input files: try all possible matches and select the longest.
944 * The key feature of this algorithm is that insertions into the string
945 * dictionary are very simple and thus fast, and deletions are avoided
946 * completely. Insertions are performed at each input character, whereas
947 * string matches are performed only when the previous match ends. So it
948 * is preferable to spend more time in matches to allow very fast string
949 * insertions and avoid deletions. The matching algorithm for small
950 * strings is inspired from that of Rabin & Karp. A brute force approach
951 * is used to find longer strings when a small match has been found.
952 * A similar algorithm is used in comic (by Jan-Mark Wams) and freeze
953 * (by Leonid Broukhis).
954 * A previous version of this file used a more sophisticated algorithm
955 * (by Fiala and Greene) which is guaranteed to run in linear amortized
956 * time, but has a larger average cost, uses more memory and is patented.
957 * However the F&G algorithm may be faster for some highly redundant
958 * files if the parameter max_chain_length (described below) is too large.
962 * The idea of lazy evaluation of matches is due to Jan-Mark Wams, and
963 * I found it in 'freeze' written by Leonid Broukhis.
964 * Thanks to many info-zippers for bug reports and testing.
968 * APPNOTE.TXT documentation file in PKZIP 1.93a distribution.
970 * A description of the Rabin and Karp algorithm is given in the book
971 * "Algorithms" by R. Sedgewick, Addison-Wesley, p252.
973 * Fiala,E.R., and Greene,D.H.
974 * Data Compression with Finite Windows, Comm.ACM, 32,4 (1989) 490-595
978 * void lm_init (int pack_level, ush *flags)
979 * Initialize the "longest match" routines for a new file
982 * Processes a new input file and return its compressed length. Sets
983 * the compressed length, crc, deflate flags and internal file
989 /* ===========================================================================
990 * Configuration parameters
993 /* Compile with MEDIUM_MEM to reduce the memory requirements or
994 * with SMALL_MEM to use as little memory as possible. Use BIG_MEM if the
995 * entire input file can be held in memory (not possible on 16 bit systems).
996 * Warning: defining these symbols affects HASH_BITS (see below) and thus
997 * affects the compression ratio. The compressed output
998 * is still correct, and might even be smaller in some cases.
1002 # define HASH_BITS 13 /* Number of bits used to hash strings */
1005 # define HASH_BITS 14
1008 # define HASH_BITS 15
1009 /* For portability to 16 bit machines, do not use values above 15. */
1012 /* To save space (see unlzw.c), we overlay prev+head with tab_prefix and
1013 * window with tab_suffix. Check that we can do this:
1015 #if (WSIZE<<1) > (1<<BITS)
1016 error:cannot overlay window with tab_suffix and prev with tab_prefix0
1018 #if HASH_BITS > BITS-1
1019 error:cannot overlay head with tab_prefix1
1021 #define HASH_SIZE (unsigned)(1<<HASH_BITS)
1022 #define HASH_MASK (HASH_SIZE-1)
1023 #define WMASK (WSIZE-1)
1024 /* HASH_SIZE and WSIZE must be powers of two */
1026 /* Tail of hash chains */
1029 /* speed options for the general purpose bit flag */
1031 # define TOO_FAR 4096
1033 /* Matches of length 3 are discarded if their distance exceeds TOO_FAR */
1034 /* ===========================================================================
1035 * Local data used by the "longest match" routines.
1038 typedef unsigned IPos;
1040 /* A Pos is an index in the character window. We use short instead of int to
1041 * save space in the various tables. IPos is used only for parameter passing.
1044 /* DECLARE(uch, window, 2L*WSIZE); */
1045 /* Sliding window. Input bytes are read into the second half of the window,
1046 * and move to the first half later to keep a dictionary of at least WSIZE
1047 * bytes. With this organization, matches are limited to a distance of
1048 * WSIZE-MAX_MATCH bytes, but this ensures that IO is always
1049 * performed with a length multiple of the block size. Also, it limits
1050 * the window size to 64K, which is quite useful on MSDOS.
1051 * To do: limit the window size to WSIZE+BSZ if SMALL_MEM (the code would
1052 * be less efficient).
1055 /* DECLARE(Pos, prev, WSIZE); */
1056 /* Link to older string with same hash index. To limit the size of this
1057 * array to 64K, this link is maintained only for the last 32K strings.
1058 * An index in this array is thus a window index modulo 32K.
1061 /* DECLARE(Pos, head, 1<<HASH_BITS); */
1062 /* Heads of the hash chains or NIL. */
1064 ulg window_size = (ulg) 2 * WSIZE;
1066 /* window size, 2*WSIZE except for MMAP or BIG_MEM, where it is the
1067 * input file length plus MIN_LOOKAHEAD.
1072 /* window position at the beginning of the current output block. Gets
1073 * negative when the window is moved backwards.
1076 local unsigned ins_h; /* hash index of string to be inserted */
1078 #define H_SHIFT ((HASH_BITS+MIN_MATCH-1)/MIN_MATCH)
1079 /* Number of bits by which ins_h and del_h must be shifted at each
1080 * input step. It must be such that after MIN_MATCH steps, the oldest
1081 * byte no longer takes part in the hash key, that is:
1082 * H_SHIFT * MIN_MATCH >= HASH_BITS
1085 unsigned int near prev_length;
1087 /* Length of the best match at previous step. Matches not greater than this
1088 * are discarded. This is used in the lazy match evaluation.
1091 unsigned near strstart; /* start of string to insert */
1092 unsigned near match_start; /* start of matching string */
1093 local int eofile; /* flag set at end of input file */
1094 local unsigned lookahead; /* number of valid bytes ahead in window */
1096 unsigned near max_chain_length;
1098 /* To speed up deflation, hash chains are never searched beyond this length.
1099 * A higher limit improves compression ratio but degrades the speed.
1102 local unsigned int max_lazy_match;
1104 /* Attempt to find a better match only when the current match is strictly
1105 * smaller than this value. This mechanism is used only for compression
1108 #define max_insert_length max_lazy_match
1109 /* Insert new strings in the hash table only if the match length
1110 * is not greater than this length. This saves time but degrades compression.
1111 * max_insert_length is used only for compression levels <= 3.
1114 unsigned near good_match;
1116 /* Use a faster search when the previous match is longer than this */
1119 /* Values for max_lazy_match, good_match and max_chain_length, depending on
1120 * the desired pack level (0..9). The values given below have been tuned to
1121 * exclude worst case performance for pathological files. Better values may be
1122 * found for specific files.
1125 typedef struct config {
1126 ush good_length; /* reduce lazy search above this match length */
1127 ush max_lazy; /* do not perform lazy search above this match length */
1128 ush nice_length; /* quit search above this match length */
1133 # define nice_match MAX_MATCH
1135 int near nice_match; /* Stop searching when current match exceeds this */
1138 local config configuration_table =
1139 /* 9 */ { 32, 258, 258, 4096 };
1140 /* maximum compression */
1142 /* Note: the deflate() code requires max_lazy >= MIN_MATCH and max_chain >= 4
1143 * For deflate_fast() (levels <= 3) good is ignored and lazy has a different
1148 /* result of memcmp for equal strings */
1150 /* ===========================================================================
1151 * Prototypes for local functions.
1153 local void fill_window OF((void));
1155 int longest_match OF((IPos cur_match));
1158 void match_init OF((void)); /* asm code initialization */
1162 local void check_match OF((IPos start, IPos match, int length));
1165 /* ===========================================================================
1166 * Update a hash value with the given input byte
1167 * IN assertion: all calls to to UPDATE_HASH are made with consecutive
1168 * input characters, so that a running hash key can be computed from the
1169 * previous key instead of complete recalculation each time.
1171 #define UPDATE_HASH(h,c) (h = (((h)<<H_SHIFT) ^ (c)) & HASH_MASK)
1173 /* ===========================================================================
1174 * Insert string s in the dictionary and set match_head to the previous head
1175 * of the hash chain (the most recent string with same hash key). Return
1176 * the previous length of the hash chain.
1177 * IN assertion: all calls to to INSERT_STRING are made with consecutive
1178 * input characters and the first MIN_MATCH bytes of s are valid
1179 * (except for the last MIN_MATCH-1 bytes of the input file).
1181 #define INSERT_STRING(s, match_head) \
1182 (UPDATE_HASH(ins_h, window[(s) + MIN_MATCH-1]), \
1183 prev[(s) & WMASK] = match_head = head[ins_h], \
1186 /* ===========================================================================
1187 * Initialize the "longest match" routines for a new file
1190 ush *flags; /* general purpose bit flag */
1192 register unsigned j;
1194 /* Initialize the hash table. */
1195 #if defined(MAXSEG_64K) && HASH_BITS == 15
1196 for (j = 0; j < HASH_SIZE; j++)
1199 memzero((char *) head, HASH_SIZE * sizeof(*head));
1201 /* prev will be initialized on the fly */
1203 /* Set the default configuration parameters:
1205 max_lazy_match = configuration_table.max_lazy;
1206 good_match = configuration_table.good_length;
1208 nice_match = configuration_table.nice_length;
1210 max_chain_length = configuration_table.max_chain;
1212 /* ??? reduce max_chain_length for binary files */
1217 match_init(); /* initialize the asm code */
1220 lookahead = read_buf((char *) window,
1221 sizeof(int) <= 2 ? (unsigned) WSIZE : 2 * WSIZE);
1223 if (lookahead == 0 || lookahead == (unsigned) EOF) {
1224 eofile = 1, lookahead = 0;
1228 /* Make sure that we always have enough lookahead. This is important
1229 * if input comes from a device such as a tty.
1231 while (lookahead < MIN_LOOKAHEAD && !eofile)
1235 for (j = 0; j < MIN_MATCH - 1; j++)
1236 UPDATE_HASH(ins_h, window[j]);
1237 /* If lookahead < MIN_MATCH, ins_h is garbage, but this is
1238 * not important since only literal bytes will be emitted.
1242 /* ===========================================================================
1243 * Set match_start to the longest match starting at the given string and
1244 * return its length. Matches shorter or equal to prev_length are discarded,
1245 * in which case the result is equal to prev_length and match_start is
1247 * IN assertions: cur_match is the head of the hash chain for the current
1248 * string (strstart) and its distance is <= MAX_DIST, and prev_length >= 1
1251 /* For MSDOS, OS/2 and 386 Unix, an optimized version is in match.asm or
1252 * match.s. The code is functionally equivalent, so you can use the C version
1255 int longest_match(cur_match)
1256 IPos cur_match; /* current match */
1258 unsigned chain_length = max_chain_length; /* max hash chain length */
1259 register uch *scan = window + strstart; /* current string */
1260 register uch *match; /* matched string */
1261 register int len; /* length of current match */
1262 int best_len = prev_length; /* best match length so far */
1265 strstart > (IPos) MAX_DIST ? strstart - (IPos) MAX_DIST : NIL;
1266 /* Stop when cur_match becomes <= limit. To simplify the code,
1267 * we prevent matches with the string of window index 0.
1270 /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16.
1271 * It is easy to get rid of this optimization if necessary.
1273 #if HASH_BITS < 8 || MAX_MATCH != 258
1274 error:Code too clever
1277 /* Compare two bytes at a time. Note: this is not always beneficial.
1278 * Try with and without -DUNALIGNED_OK to check.
1280 register uch *strend = window + strstart + MAX_MATCH - 1;
1281 register ush scan_start = *(ush *) scan;
1282 register ush scan_end = *(ush *) (scan + best_len - 1);
1284 register uch *strend = window + strstart + MAX_MATCH;
1285 register uch scan_end1 = scan[best_len - 1];
1286 register uch scan_end = scan[best_len];
1289 /* Do not waste too much time if we already have a good match: */
1290 if (prev_length >= good_match) {
1293 Assert(strstart <= window_size - MIN_LOOKAHEAD,
1294 "insufficient lookahead");
1297 Assert(cur_match < strstart, "no future");
1298 match = window + cur_match;
1300 /* Skip to next match if the match length cannot increase
1301 * or if the match length is less than 2:
1303 #if (defined(UNALIGNED_OK) && MAX_MATCH == 258)
1304 /* This code assumes sizeof(unsigned short) == 2. Do not use
1305 * UNALIGNED_OK if your compiler uses a different size.
1307 if (*(ush *) (match + best_len - 1) != scan_end ||
1308 *(ush *) match != scan_start)
1311 /* It is not necessary to compare scan[2] and match[2] since they are
1312 * always equal when the other bytes match, given that the hash keys
1313 * are equal and that HASH_BITS >= 8. Compare 2 bytes at a time at
1314 * strstart+3, +5, ... up to strstart+257. We check for insufficient
1315 * lookahead only every 4th comparison; the 128th check will be made
1316 * at strstart+257. If MAX_MATCH-2 is not a multiple of 8, it is
1317 * necessary to put more guard bytes at the end of the window, or
1318 * to check more often for insufficient lookahead.
1322 } while (*(ush *) (scan += 2) == *(ush *) (match += 2) &&
1323 *(ush *) (scan += 2) == *(ush *) (match += 2) &&
1324 *(ush *) (scan += 2) == *(ush *) (match += 2) &&
1325 *(ush *) (scan += 2) == *(ush *) (match += 2) &&
1327 /* The funny "do {}" generates better code on most compilers */
1329 /* Here, scan <= window+strstart+257 */
1330 Assert(scan <= window + (unsigned) (window_size - 1), "wild scan");
1331 if (*scan == *match)
1334 len = (MAX_MATCH - 1) - (int) (strend - scan);
1335 scan = strend - (MAX_MATCH - 1);
1337 #else /* UNALIGNED_OK */
1339 if (match[best_len] != scan_end ||
1340 match[best_len - 1] != scan_end1 ||
1341 *match != *scan || *++match != scan[1])
1344 /* The check at best_len-1 can be removed because it will be made
1345 * again later. (This heuristic is not always a win.)
1346 * It is not necessary to compare scan[2] and match[2] since they
1347 * are always equal when the other bytes match, given that
1348 * the hash keys are equal and that HASH_BITS >= 8.
1352 /* We check for insufficient lookahead only every 8th comparison;
1353 * the 256th check will be made at strstart+258.
1356 } while (*++scan == *++match && *++scan == *++match &&
1357 *++scan == *++match && *++scan == *++match &&
1358 *++scan == *++match && *++scan == *++match &&
1359 *++scan == *++match && *++scan == *++match &&
1362 len = MAX_MATCH - (int) (strend - scan);
1363 scan = strend - MAX_MATCH;
1365 #endif /* UNALIGNED_OK */
1367 if (len > best_len) {
1368 match_start = cur_match;
1370 if (len >= nice_match)
1373 scan_end = *(ush *) (scan + best_len - 1);
1375 scan_end1 = scan[best_len - 1];
1376 scan_end = scan[best_len];
1379 } while ((cur_match = prev[cur_match & WMASK]) > limit
1380 && --chain_length != 0);
1387 /* ===========================================================================
1388 * Check that the match at match_start is indeed a match.
1390 local void check_match(start, match, length)
1394 /* check that the match is indeed a match */
1395 if (memcmp((char *) window + match,
1396 (char *) window + start, length) != EQUAL) {
1398 " start %d, match %d, length %d\n", start, match, length);
1399 error("invalid match");
1402 fprintf(stderr, "\\[%d,%d]", start - match, length);
1404 putc(window[start++], stderr);
1405 } while (--length != 0);
1409 # define check_match(start, match, length)
1412 /* ===========================================================================
1413 * Fill the window when the lookahead becomes insufficient.
1414 * Updates strstart and lookahead, and sets eofile if end of input file.
1415 * IN assertion: lookahead < MIN_LOOKAHEAD && strstart + lookahead > 0
1416 * OUT assertions: at least one byte has been read, or eofile is set;
1417 * file reads are performed for at least two bytes (required for the
1418 * translate_eol option).
1420 local void fill_window()
1422 register unsigned n, m;
1425 (unsigned) (window_size - (ulg) lookahead - (ulg) strstart);
1426 /* Amount of free space at the end of the window. */
1428 /* If the window is almost full and there is insufficient lookahead,
1429 * move the upper half to the lower one to make room in the upper half.
1431 if (more == (unsigned) EOF) {
1432 /* Very unlikely, but possible on 16 bit machine if strstart == 0
1433 * and lookahead == 1 (input done one byte at time)
1436 } else if (strstart >= WSIZE + MAX_DIST) {
1437 /* By the IN assertion, the window is not empty so we can't confuse
1438 * more == 0 with more == 64K on a 16 bit machine.
1440 Assert(window_size == (ulg) 2 * WSIZE, "no sliding with BIG_MEM");
1442 memcpy((char *) window, (char *) window + WSIZE, (unsigned) WSIZE);
1443 match_start -= WSIZE;
1444 strstart -= WSIZE; /* we now have strstart >= MAX_DIST: */
1446 block_start -= (long) WSIZE;
1448 for (n = 0; n < HASH_SIZE; n++) {
1450 head[n] = (Pos) (m >= WSIZE ? m - WSIZE : NIL);
1452 for (n = 0; n < WSIZE; n++) {
1454 prev[n] = (Pos) (m >= WSIZE ? m - WSIZE : NIL);
1455 /* If n is not on any hash chain, prev[n] is garbage but
1456 * its value will never be used.
1461 /* At this point, more >= 2 */
1463 n = read_buf((char *) window + strstart + lookahead, more);
1464 if (n == 0 || n == (unsigned) EOF) {
1472 /* ===========================================================================
1473 * Flush the current block, with given end-of-file flag.
1474 * IN assertion: strstart is set to the end of the current match.
1476 #define FLUSH_BLOCK(eof) \
1477 flush_block(block_start >= 0L ? (char*)&window[(unsigned)block_start] : \
1478 (char*)NULL, (long)strstart - block_start, (eof))
1480 /* ===========================================================================
1481 * Same as above, but achieves better compression. We use a lazy
1482 * evaluation for matches: a match is finally adopted only if there is
1483 * no better match at the next window position.
1487 IPos hash_head; /* head of hash chain */
1488 IPos prev_match; /* previous match */
1489 int flush; /* set if current block must be flushed */
1490 int match_available = 0; /* set if previous match exists */
1491 register unsigned match_length = MIN_MATCH - 1; /* length of best match */
1494 extern long isize; /* byte length of input file, for debug only */
1497 /* Process the input block. */
1498 while (lookahead != 0) {
1499 /* Insert the string window[strstart .. strstart+2] in the
1500 * dictionary, and set hash_head to the head of the hash chain:
1502 INSERT_STRING(strstart, hash_head);
1504 /* Find the longest match, discarding those <= prev_length.
1506 prev_length = match_length, prev_match = match_start;
1507 match_length = MIN_MATCH - 1;
1509 if (hash_head != NIL && prev_length < max_lazy_match &&
1510 strstart - hash_head <= MAX_DIST) {
1511 /* To simplify the code, we prevent matches with the string
1512 * of window index 0 (in particular we have to avoid a match
1513 * of the string with itself at the start of the input file).
1515 match_length = longest_match(hash_head);
1516 /* longest_match() sets match_start */
1517 if (match_length > lookahead)
1518 match_length = lookahead;
1520 /* Ignore a length 3 match if it is too distant: */
1521 if (match_length == MIN_MATCH
1522 && strstart - match_start > TOO_FAR) {
1523 /* If prev_match is also MIN_MATCH, match_start is garbage
1524 * but we will ignore the current match anyway.
1529 /* If there was a match at the previous step and the current
1530 * match is not better, output the previous match:
1532 if (prev_length >= MIN_MATCH && match_length <= prev_length) {
1534 check_match(strstart - 1, prev_match, prev_length);
1537 ct_tally(strstart - 1 - prev_match,
1538 prev_length - MIN_MATCH);
1540 /* Insert in hash table all strings up to the end of the match.
1541 * strstart-1 and strstart are already inserted.
1543 lookahead -= prev_length - 1;
1547 INSERT_STRING(strstart, hash_head);
1548 /* strstart never exceeds WSIZE-MAX_MATCH, so there are
1549 * always MIN_MATCH bytes ahead. If lookahead < MIN_MATCH
1550 * these bytes are garbage, but it does not matter since the
1551 * next lookahead bytes will always be emitted as literals.
1553 } while (--prev_length != 0);
1554 match_available = 0;
1555 match_length = MIN_MATCH - 1;
1558 FLUSH_BLOCK(0), block_start = strstart;
1560 } else if (match_available) {
1561 /* If there was no match at the previous position, output a
1562 * single literal. If there was a match but the current match
1563 * is longer, truncate the previous match to a single literal.
1565 Tracevv((stderr, "%c", window[strstart - 1]));
1566 if (ct_tally(0, window[strstart - 1])) {
1567 FLUSH_BLOCK(0), block_start = strstart;
1572 /* There is no previous match to compare with, wait for
1573 * the next step to decide.
1575 match_available = 1;
1579 Assert(strstart <= isize && lookahead <= isize, "a bit too far");
1581 /* Make sure that we always have enough lookahead, except
1582 * at the end of the input file. We need MAX_MATCH bytes
1583 * for the next match, plus MIN_MATCH bytes to insert the
1584 * string following the next match.
1586 while (lookahead < MIN_LOOKAHEAD && !eofile)
1589 if (match_available)
1590 ct_tally(0, window[strstart - 1]);
1592 return FLUSH_BLOCK(1); /* eof */
1595 /* gzip (GNU zip) -- compress files with zip algorithm and 'compress' interface
1596 * Copyright (C) 1992-1993 Jean-loup Gailly
1597 * The unzip code was written and put in the public domain by Mark Adler.
1598 * Portions of the lzw code are derived from the public domain 'compress'
1599 * written by Spencer Thomas, Joe Orost, James Woods, Jim McKie, Steve Davies,
1600 * Ken Turkowski, Dave Mack and Peter Jannesen.
1602 * See the license_msg below and the file COPYING for the software license.
1603 * See the file algorithm.doc for the compression algorithms and file formats.
1606 /* Compress files with zip algorithm and 'compress' interface.
1607 * See usage() and help() functions below for all options.
1609 * file.gz: compressed file with same mode, owner, and utimes
1610 * or stdout with -c option or if stdin used as input.
1611 * If the output file name had to be truncated, the original name is kept
1612 * in the compressed file.
1613 * On MSDOS, file.tmp -> file.tmz. On VMS, file.tmp -> file.tmp-gz.
1615 * Using gz on MSDOS would create too many file name conflicts. For
1616 * example, foo.txt -> foo.tgz (.tgz must be reserved as shorthand for
1617 * tar.gz). Similarly, foo.dir and foo.doc would both be mapped to foo.dgz.
1618 * I also considered 12345678.txt -> 12345txt.gz but this truncates the name
1619 * too heavily. There is no ideal solution given the MSDOS 8+3 limitation.
1621 * For the meaning of all compilation flags, see comments in Makefile.in.
1625 #include <sys/types.h>
1627 #include <sys/stat.h>
1633 # include <sys/time.h>
1642 #ifdef HAVE_UNISTD_H
1643 # include <unistd.h>
1646 #if defined(STDC_HEADERS) || !defined(NO_STDLIB_H)
1647 # include <stdlib.h>
1653 # include <dirent.h>
1654 typedef struct dirent dir_type;
1656 # define NLENGTH(dirent) ((int)strlen((dirent)->d_name))
1657 # define DIR_OPT "DIRENT"
1659 # define NLENGTH(dirent) ((dirent)->d_namlen)
1661 # include <sys/dir.h>
1662 typedef struct direct dir_type;
1664 # define DIR_OPT "SYSDIR"
1667 # include <sys/ndir.h>
1668 typedef struct direct dir_type;
1670 # define DIR_OPT "SYSNDIR"
1674 typedef struct direct dir_type;
1676 # define DIR_OPT "NDIR"
1679 # define DIR_OPT "NO_DIR"
1688 # define TIME_OPT "UTIME"
1690 # ifdef HAVE_SYS_UTIME_H
1691 # include <sys/utime.h>
1692 # define TIME_OPT "SYS_UTIME"
1699 # define TIME_OPT ""
1703 # define TIME_OPT "NO_UTIME"
1706 #if !defined(S_ISDIR) && defined(S_IFDIR)
1707 # define S_ISDIR(m) (((m) & S_IFMT) == S_IFDIR)
1709 #if !defined(S_ISREG) && defined(S_IFREG)
1710 # define S_ISREG(m) (((m) & S_IFMT) == S_IFREG)
1713 typedef RETSIGTYPE(*sig_type) OF((int));
1716 # define O_BINARY 0 /* creation mode for open() */
1720 /* Pure BSD system? */
1721 # include <sys/file.h>
1723 # define O_CREAT FCREAT
1726 # define O_EXCL FEXCL
1731 # define S_IRUSR 0400
1734 # define S_IWUSR 0200
1736 #define RW_USER (S_IRUSR | S_IWUSR) /* creation mode for open() */
1738 #ifndef MAX_PATH_LEN
1739 # define MAX_PATH_LEN 1024 /* max pathname length */
1748 off_t lseek OF((int fd, off_t offset, int whence));
1751 /* Separator for file name parts (see shorten_name()) */
1752 #ifdef NO_MULTIPLE_DOTS
1753 # define PART_SEP "-"
1755 # define PART_SEP "."
1758 /* global buffers */
1760 DECLARE(uch, inbuf, INBUFSIZ + INBUF_EXTRA);
1761 DECLARE(uch, outbuf, OUTBUFSIZ + OUTBUF_EXTRA);
1762 DECLARE(ush, d_buf, DIST_BUFSIZE);
1763 DECLARE(uch, window, 2L * WSIZE);
1765 DECLARE(ush, tab_prefix, 1L << BITS);
1767 DECLARE(ush, tab_prefix0, 1L << (BITS - 1));
1768 DECLARE(ush, tab_prefix1, 1L << (BITS - 1));
1771 /* local variables */
1773 int ascii = 0; /* convert end-of-lines to local OS conventions */
1774 int decompress = 0; /* decompress (-d) */
1775 int no_name = -1; /* don't save or restore the original file name */
1776 int no_time = -1; /* don't save or restore the original file time */
1777 int foreground; /* set if program run in foreground */
1778 char *progname; /* program name */
1779 static int method = DEFLATED; /* compression method */
1780 static int exit_code = OK; /* program exit code */
1781 int save_orig_name; /* set if original name must be saved */
1782 int last_member; /* set for .zip and .Z files */
1783 int part_nb; /* number of parts in .gz file */
1784 long time_stamp; /* original time stamp (modification time) */
1785 long ifile_size; /* input file size, -1 for devices (debug only) */
1786 char *env; /* contents of GZIP env variable */
1787 char **args = NULL; /* argv pointer if GZIP env variable defined */
1788 char z_suffix[MAX_SUFFIX + 1]; /* default suffix (can be set with --suffix) */
1789 int z_len; /* strlen(z_suffix) */
1791 long bytes_in; /* number of input bytes */
1792 long bytes_out; /* number of output bytes */
1793 char ifname[MAX_PATH_LEN]; /* input file name */
1794 char ofname[MAX_PATH_LEN]; /* output file name */
1795 int remove_ofname = 0; /* remove output file on error */
1796 struct stat istat; /* status for input file */
1797 int ifd; /* input file descriptor */
1798 int ofd; /* output file descriptor */
1799 unsigned insize; /* valid bytes in inbuf */
1800 unsigned inptr; /* index of next byte to be processed in inbuf */
1801 unsigned outcnt; /* bytes in output buffer */
1803 /* local functions */
1805 #define strequ(s1, s2) (strcmp((s1),(s2)) == 0)
1807 /* ======================================================================== */
1808 // int main (argc, argv)
1811 int gzip_main(int argc, char **argv)
1816 struct stat statBuf;
1824 /* Parse any options */
1825 while (--argc > 0 && **(++argv) == '-') {
1826 if (*((*argv) + 1) == '\0') {
1830 while (*(++(*argv))) {
1841 foreground = signal(SIGINT, SIG_IGN) != SIG_IGN;
1843 (void) signal(SIGINT, (sig_type) abort_gzip);
1846 if (signal(SIGTERM, SIG_IGN) != SIG_IGN) {
1847 (void) signal(SIGTERM, (sig_type) abort_gzip);
1851 if (signal(SIGHUP, SIG_IGN) != SIG_IGN) {
1852 (void) signal(SIGHUP, (sig_type) abort_gzip);
1856 strncpy(z_suffix, Z_SUFFIX, sizeof(z_suffix) - 1);
1857 z_len = strlen(z_suffix);
1859 /* Allocate all global buffers (for DYN_ALLOC option) */
1860 ALLOC(uch, inbuf, INBUFSIZ + INBUF_EXTRA);
1861 ALLOC(uch, outbuf, OUTBUFSIZ + OUTBUF_EXTRA);
1862 ALLOC(ush, d_buf, DIST_BUFSIZE);
1863 ALLOC(uch, window, 2L * WSIZE);
1865 ALLOC(ush, tab_prefix, 1L << BITS);
1867 ALLOC(ush, tab_prefix0, 1L << (BITS - 1));
1868 ALLOC(ush, tab_prefix1, 1L << (BITS - 1));
1871 if (fromstdin == 1) {
1872 strcpy(ofname, "stdin");
1874 inFileNum = fileno(stdin);
1875 time_stamp = 0; /* time unknown by default */
1876 ifile_size = -1L; /* convention for unknown size */
1878 /* Open up the input file */
1881 strncpy(ifname, *argv, MAX_PATH_LEN);
1883 /* Open input fille */
1884 inFileNum = open(ifname, O_RDONLY);
1885 if (inFileNum < 0) {
1889 /* Get the time stamp on the input file. */
1890 result = stat(ifname, &statBuf);
1895 time_stamp = statBuf.st_ctime;
1896 ifile_size = statBuf.st_size;
1900 if (tostdout == 1) {
1901 /* And get to work */
1902 strcpy(ofname, "stdout");
1903 outFileNum = fileno(stdout);
1904 SET_BINARY_MODE(fileno(stdout));
1906 clear_bufs(); /* clear input and output buffers */
1909 /* Actually do the compression/decompression. */
1910 zip(inFileNum, outFileNum);
1914 /* And get to work */
1915 strncpy(ofname, ifname, MAX_PATH_LEN - 4);
1916 strcat(ofname, ".gz");
1919 /* Open output fille */
1920 #if (__GLIBC__ >= 2) && (__GLIBC_MINOR__ >= 1)
1921 outFileNum = open(ofname, O_RDWR | O_CREAT | O_EXCL | O_NOFOLLOW);
1923 outFileNum = open(ofname, O_RDWR | O_CREAT | O_EXCL);
1925 if (outFileNum < 0) {
1929 SET_BINARY_MODE(outFileNum);
1930 /* Set permissions on the file */
1931 fchmod(outFileNum, statBuf.st_mode);
1933 clear_bufs(); /* clear input and output buffers */
1936 /* Actually do the compression/decompression. */
1937 result = zip(inFileNum, outFileNum);
1940 /* Delete the original file */
1942 delFileName = ifname;
1944 delFileName = ofname;
1946 if (unlink(delFileName) < 0) {
1947 perror(delFileName);
1955 /* trees.c -- output deflated data using Huffman coding
1956 * Copyright (C) 1992-1993 Jean-loup Gailly
1957 * This is free software; you can redistribute it and/or modify it under the
1958 * terms of the GNU General Public License, see the file COPYING.
1964 * Encode various sets of source values using variable-length
1965 * binary code trees.
1969 * The PKZIP "deflation" process uses several Huffman trees. The more
1970 * common source values are represented by shorter bit sequences.
1972 * Each code tree is stored in the ZIP file in a compressed form
1973 * which is itself a Huffman encoding of the lengths of
1974 * all the code strings (in ascending order by source values).
1975 * The actual code strings are reconstructed from the lengths in
1976 * the UNZIP process, as described in the "application note"
1977 * (APPNOTE.TXT) distributed as part of PKWARE's PKZIP program.
1982 * Data Compression: Techniques and Applications, pp. 53-55.
1983 * Lifetime Learning Publications, 1985. ISBN 0-534-03418-7.
1986 * Data Compression: Methods and Theory, pp. 49-50.
1987 * Computer Science Press, 1988. ISBN 0-7167-8156-5.
1991 * Addison-Wesley, 1983. ISBN 0-201-06672-6.
1995 * void ct_init (ush *attr, int *methodp)
1996 * Allocate the match buffer, initialize the various tables and save
1997 * the location of the internal file attribute (ascii/binary) and
1998 * method (DEFLATE/STORE)
2000 * void ct_tally (int dist, int lc);
2001 * Save the match info and tally the frequency counts.
2003 * long flush_block (char *buf, ulg stored_len, int eof)
2004 * Determine the best encoding for the current block: dynamic trees,
2005 * static trees or store, and output the encoded block to the zip
2006 * file. Returns the total compressed length for the file so far.
2012 /* ===========================================================================
2017 /* All codes must not exceed MAX_BITS bits */
2019 #define MAX_BL_BITS 7
2020 /* Bit length codes must not exceed MAX_BL_BITS bits */
2022 #define LENGTH_CODES 29
2023 /* number of length codes, not counting the special END_BLOCK code */
2025 #define LITERALS 256
2026 /* number of literal bytes 0..255 */
2028 #define END_BLOCK 256
2029 /* end of block literal code */
2031 #define L_CODES (LITERALS+1+LENGTH_CODES)
2032 /* number of Literal or Length codes, including the END_BLOCK code */
2035 /* number of distance codes */
2038 /* number of codes used to transfer the bit lengths */
2041 local int near extra_lbits[LENGTH_CODES] /* extra bits for each length code */
2042 = { 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4,
2043 4, 4, 5, 5, 5, 5, 0 };
2045 local int near extra_dbits[D_CODES] /* extra bits for each distance code */
2046 = { 0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6, 7, 7, 8, 8, 9, 9,
2047 10, 10, 11, 11, 12, 12, 13, 13 };
2049 local int near extra_blbits[BL_CODES] /* extra bits for each bit length code */
2050 = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 3, 7 };
2052 #define STORED_BLOCK 0
2053 #define STATIC_TREES 1
2055 /* The three kinds of block type */
2059 # define LIT_BUFSIZE 0x2000
2062 # define LIT_BUFSIZE 0x4000
2064 # define LIT_BUFSIZE 0x8000
2068 #ifndef DIST_BUFSIZE
2069 # define DIST_BUFSIZE LIT_BUFSIZE
2071 /* Sizes of match buffers for literals/lengths and distances. There are
2072 * 4 reasons for limiting LIT_BUFSIZE to 64K:
2073 * - frequencies can be kept in 16 bit counters
2074 * - if compression is not successful for the first block, all input data is
2075 * still in the window so we can still emit a stored block even when input
2076 * comes from standard input. (This can also be done for all blocks if
2077 * LIT_BUFSIZE is not greater than 32K.)
2078 * - if compression is not successful for a file smaller than 64K, we can
2079 * even emit a stored file instead of a stored block (saving 5 bytes).
2080 * - creating new Huffman trees less frequently may not provide fast
2081 * adaptation to changes in the input data statistics. (Take for
2082 * example a binary file with poorly compressible code followed by
2083 * a highly compressible string table.) Smaller buffer sizes give
2084 * fast adaptation but have of course the overhead of transmitting trees
2086 * - I can't count above 4
2087 * The current code is general and allows DIST_BUFSIZE < LIT_BUFSIZE (to save
2088 * memory at the expense of compression). Some optimizations would be possible
2089 * if we rely on DIST_BUFSIZE == LIT_BUFSIZE.
2091 #if LIT_BUFSIZE > INBUFSIZ
2092 error cannot overlay l_buf and inbuf
2095 /* repeat previous bit length 3-6 times (2 bits of repeat count) */
2096 #define REPZ_3_10 17
2097 /* repeat a zero length 3-10 times (3 bits of repeat count) */
2098 #define REPZ_11_138 18
2099 /* repeat a zero length 11-138 times (7 bits of repeat count) *//* ===========================================================================
2101 *//* Data structure describing a single value and its code string. */ typedef struct ct_data {
2103 ush freq; /* frequency count */
2104 ush code; /* bit string */
2107 ush dad; /* father node in Huffman tree */
2108 ush len; /* length of bit string */
2112 #define Freq fc.freq
2113 #define Code fc.code
2117 #define HEAP_SIZE (2*L_CODES+1)
2118 /* maximum heap size */
2120 local ct_data near dyn_ltree[HEAP_SIZE]; /* literal and length tree */
2121 local ct_data near dyn_dtree[2 * D_CODES + 1]; /* distance tree */
2123 local ct_data near static_ltree[L_CODES + 2];
2125 /* The static literal tree. Since the bit lengths are imposed, there is no
2126 * need for the L_CODES extra codes used during heap construction. However
2127 * The codes 286 and 287 are needed to build a canonical tree (see ct_init
2131 local ct_data near static_dtree[D_CODES];
2133 /* The static distance tree. (Actually a trivial tree since all codes use
2137 local ct_data near bl_tree[2 * BL_CODES + 1];
2139 /* Huffman tree for the bit lengths */
2141 typedef struct tree_desc {
2142 ct_data near *dyn_tree; /* the dynamic tree */
2143 ct_data near *static_tree; /* corresponding static tree or NULL */
2144 int near *extra_bits; /* extra bits for each code or NULL */
2145 int extra_base; /* base index for extra_bits */
2146 int elems; /* max number of elements in the tree */
2147 int max_length; /* max bit length for the codes */
2148 int max_code; /* largest code with non zero frequency */
2151 local tree_desc near l_desc =
2152 { dyn_ltree, static_ltree, extra_lbits, LITERALS + 1, L_CODES,
2155 local tree_desc near d_desc =
2156 { dyn_dtree, static_dtree, extra_dbits, 0, D_CODES, MAX_BITS, 0 };
2158 local tree_desc near bl_desc =
2159 { bl_tree, (ct_data near *) 0, extra_blbits, 0, BL_CODES, MAX_BL_BITS,
2163 local ush near bl_count[MAX_BITS + 1];
2165 /* number of codes at each bit length for an optimal tree */
2167 local uch near bl_order[BL_CODES]
2168 = { 16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15 };
2170 /* The lengths of the bit length codes are sent in order of decreasing
2171 * probability, to avoid transmitting the lengths for unused bit length codes.
2174 local int near heap[2 * L_CODES + 1]; /* heap used to build the Huffman trees */
2175 local int heap_len; /* number of elements in the heap */
2176 local int heap_max; /* element of largest frequency */
2178 /* The sons of heap[n] are heap[2*n] and heap[2*n+1]. heap[0] is not used.
2179 * The same heap array is used to build all trees.
2182 local uch near depth[2 * L_CODES + 1];
2184 /* Depth of each subtree used as tie breaker for trees of equal frequency */
2186 local uch length_code[MAX_MATCH - MIN_MATCH + 1];
2188 /* length code for each normalized match length (0 == MIN_MATCH) */
2190 local uch dist_code[512];
2192 /* distance codes. The first 256 values correspond to the distances
2193 * 3 .. 258, the last 256 values correspond to the top 8 bits of
2194 * the 15 bit distances.
2197 local int near base_length[LENGTH_CODES];
2199 /* First normalized length for each code (0 = MIN_MATCH) */
2201 local int near base_dist[D_CODES];
2203 /* First normalized distance for each code (0 = distance of 1) */
2206 /* DECLARE(uch, l_buf, LIT_BUFSIZE); buffer for literals or lengths */
2208 /* DECLARE(ush, d_buf, DIST_BUFSIZE); buffer for distances */
2210 local uch near flag_buf[(LIT_BUFSIZE / 8)];
2212 /* flag_buf is a bit array distinguishing literals from lengths in
2213 * l_buf, thus indicating the presence or absence of a distance.
2216 local unsigned last_lit; /* running index in l_buf */
2217 local unsigned last_dist; /* running index in d_buf */
2218 local unsigned last_flags; /* running index in flag_buf */
2219 local uch flags; /* current flags not yet saved in flag_buf */
2220 local uch flag_bit; /* current bit used in flags */
2222 /* bits are filled in flags starting at bit 0 (least significant).
2223 * Note: these flags are overkill in the current code since we don't
2224 * take advantage of DIST_BUFSIZE == LIT_BUFSIZE.
2227 local ulg opt_len; /* bit length of current block with optimal trees */
2228 local ulg static_len; /* bit length of current block with static trees */
2230 local ulg compressed_len; /* total bit length of compressed file */
2232 local ulg input_len; /* total byte length of input file */
2234 /* input_len is for debugging only since we can get it by other means. */
2236 ush *file_type; /* pointer to UNKNOWN, BINARY or ASCII */
2237 int *file_method; /* pointer to DEFLATE or STORE */
2240 extern ulg bits_sent; /* bit length of the compressed data */
2241 extern long isize; /* byte length of input file */
2244 extern long block_start; /* window offset of current block */
2245 extern unsigned near strstart; /* window offset of current string */
2247 /* ===========================================================================
2248 * Local (static) routines in this file.
2251 local void init_block OF((void));
2252 local void pqdownheap OF((ct_data near * tree, int k));
2253 local void gen_bitlen OF((tree_desc near * desc));
2254 local void gen_codes OF((ct_data near * tree, int max_code));
2255 local void build_tree OF((tree_desc near * desc));
2256 local void scan_tree OF((ct_data near * tree, int max_code));
2257 local void send_tree OF((ct_data near * tree, int max_code));
2258 local int build_bl_tree OF((void));
2259 local void send_all_trees OF((int lcodes, int dcodes, int blcodes));
2260 local void compress_block OF((ct_data near * ltree, ct_data near * dtree));
2261 local void set_file_type OF((void));
2265 # define send_code(c, tree) send_bits(tree[c].Code, tree[c].Len)
2266 /* Send a code of the given tree. c and tree must not have side effects */
2269 # define send_code(c, tree) \
2270 { if (verbose>1) fprintf(stderr,"\ncd %3d ",(c)); \
2271 send_bits(tree[c].Code, tree[c].Len); }
2274 #define d_code(dist) \
2275 ((dist) < 256 ? dist_code[dist] : dist_code[256+((dist)>>7)])
2276 /* Mapping from a distance to a distance code. dist is the distance - 1 and
2277 * must not have side effects. dist_code[256] and dist_code[257] are never
2281 #define MAX(a,b) (a >= b ? a : b)
2282 /* the arguments must not have side effects */
2284 /* ===========================================================================
2285 * Allocate the match buffer, initialize the various tables and save the
2286 * location of the internal file attribute (ascii/binary) and method
2289 void ct_init(attr, methodp)
2290 ush *attr; /* pointer to internal file attribute */
2291 int *methodp; /* pointer to compression method */
2293 int n; /* iterates over tree elements */
2294 int bits; /* bit counter */
2295 int length; /* length value */
2296 int code; /* code value */
2297 int dist; /* distance index */
2300 file_method = methodp;
2301 compressed_len = input_len = 0L;
2303 if (static_dtree[0].Len != 0)
2304 return; /* ct_init already called */
2306 /* Initialize the mapping length (0..255) -> length code (0..28) */
2308 for (code = 0; code < LENGTH_CODES - 1; code++) {
2309 base_length[code] = length;
2310 for (n = 0; n < (1 << extra_lbits[code]); n++) {
2311 length_code[length++] = (uch) code;
2314 Assert(length == 256, "ct_init: length != 256");
2315 /* Note that the length 255 (match length 258) can be represented
2316 * in two different ways: code 284 + 5 bits or code 285, so we
2317 * overwrite length_code[255] to use the best encoding:
2319 length_code[length - 1] = (uch) code;
2321 /* Initialize the mapping dist (0..32K) -> dist code (0..29) */
2323 for (code = 0; code < 16; code++) {
2324 base_dist[code] = dist;
2325 for (n = 0; n < (1 << extra_dbits[code]); n++) {
2326 dist_code[dist++] = (uch) code;
2329 Assert(dist == 256, "ct_init: dist != 256");
2330 dist >>= 7; /* from now on, all distances are divided by 128 */
2331 for (; code < D_CODES; code++) {
2332 base_dist[code] = dist << 7;
2333 for (n = 0; n < (1 << (extra_dbits[code] - 7)); n++) {
2334 dist_code[256 + dist++] = (uch) code;
2337 Assert(dist == 256, "ct_init: 256+dist != 512");
2339 /* Construct the codes of the static literal tree */
2340 for (bits = 0; bits <= MAX_BITS; bits++)
2344 static_ltree[n++].Len = 8, bl_count[8]++;
2346 static_ltree[n++].Len = 9, bl_count[9]++;
2348 static_ltree[n++].Len = 7, bl_count[7]++;
2350 static_ltree[n++].Len = 8, bl_count[8]++;
2351 /* Codes 286 and 287 do not exist, but we must include them in the
2352 * tree construction to get a canonical Huffman tree (longest code
2355 gen_codes((ct_data near *) static_ltree, L_CODES + 1);
2357 /* The static distance tree is trivial: */
2358 for (n = 0; n < D_CODES; n++) {
2359 static_dtree[n].Len = 5;
2360 static_dtree[n].Code = bi_reverse(n, 5);
2363 /* Initialize the first block of the first file: */
2367 /* ===========================================================================
2368 * Initialize a new block.
2370 local void init_block()
2372 int n; /* iterates over tree elements */
2374 /* Initialize the trees. */
2375 for (n = 0; n < L_CODES; n++)
2376 dyn_ltree[n].Freq = 0;
2377 for (n = 0; n < D_CODES; n++)
2378 dyn_dtree[n].Freq = 0;
2379 for (n = 0; n < BL_CODES; n++)
2380 bl_tree[n].Freq = 0;
2382 dyn_ltree[END_BLOCK].Freq = 1;
2383 opt_len = static_len = 0L;
2384 last_lit = last_dist = last_flags = 0;
2390 /* Index within the heap array of least frequent node in the Huffman tree */
2393 /* ===========================================================================
2394 * Remove the smallest element from the heap and recreate the heap with
2395 * one less element. Updates heap and heap_len.
2397 #define pqremove(tree, top) \
2399 top = heap[SMALLEST]; \
2400 heap[SMALLEST] = heap[heap_len--]; \
2401 pqdownheap(tree, SMALLEST); \
2404 /* ===========================================================================
2405 * Compares to subtrees, using the tree depth as tie breaker when
2406 * the subtrees have equal frequency. This minimizes the worst case length.
2408 #define smaller(tree, n, m) \
2409 (tree[n].Freq < tree[m].Freq || \
2410 (tree[n].Freq == tree[m].Freq && depth[n] <= depth[m]))
2412 /* ===========================================================================
2413 * Restore the heap property by moving down the tree starting at node k,
2414 * exchanging a node with the smallest of its two sons if necessary, stopping
2415 * when the heap property is re-established (each father smaller than its
2418 local void pqdownheap(tree, k)
2419 ct_data near *tree; /* the tree to restore */
2420 int k; /* node to move down */
2423 int j = k << 1; /* left son of k */
2425 while (j <= heap_len) {
2426 /* Set j to the smallest of the two sons: */
2427 if (j < heap_len && smaller(tree, heap[j + 1], heap[j]))
2430 /* Exit if v is smaller than both sons */
2431 if (smaller(tree, v, heap[j]))
2434 /* Exchange v with the smallest son */
2438 /* And continue down the tree, setting j to the left son of k */
2444 /* ===========================================================================
2445 * Compute the optimal bit lengths for a tree and update the total bit length
2446 * for the current block.
2447 * IN assertion: the fields freq and dad are set, heap[heap_max] and
2448 * above are the tree nodes sorted by increasing frequency.
2449 * OUT assertions: the field len is set to the optimal bit length, the
2450 * array bl_count contains the frequencies for each bit length.
2451 * The length opt_len is updated; static_len is also updated if stree is
2454 local void gen_bitlen(desc)
2455 tree_desc near *desc; /* the tree descriptor */
2457 ct_data near *tree = desc->dyn_tree;
2458 int near *extra = desc->extra_bits;
2459 int base = desc->extra_base;
2460 int max_code = desc->max_code;
2461 int max_length = desc->max_length;
2462 ct_data near *stree = desc->static_tree;
2463 int h; /* heap index */
2464 int n, m; /* iterate over the tree elements */
2465 int bits; /* bit length */
2466 int xbits; /* extra bits */
2467 ush f; /* frequency */
2468 int overflow = 0; /* number of elements with bit length too large */
2470 for (bits = 0; bits <= MAX_BITS; bits++)
2473 /* In a first pass, compute the optimal bit lengths (which may
2474 * overflow in the case of the bit length tree).
2476 tree[heap[heap_max]].Len = 0; /* root of the heap */
2478 for (h = heap_max + 1; h < HEAP_SIZE; h++) {
2480 bits = tree[tree[n].Dad].Len + 1;
2481 if (bits > max_length)
2482 bits = max_length, overflow++;
2483 tree[n].Len = (ush) bits;
2484 /* We overwrite tree[n].Dad which is no longer needed */
2487 continue; /* not a leaf node */
2492 xbits = extra[n - base];
2494 opt_len += (ulg) f *(bits + xbits);
2497 static_len += (ulg) f *(stree[n].Len + xbits);
2502 Trace((stderr, "\nbit length overflow\n"));
2503 /* This happens for example on obj2 and pic of the Calgary corpus */
2505 /* Find the first bit length which could increase: */
2507 bits = max_length - 1;
2508 while (bl_count[bits] == 0)
2510 bl_count[bits]--; /* move one leaf down the tree */
2511 bl_count[bits + 1] += 2; /* move one overflow item as its brother */
2512 bl_count[max_length]--;
2513 /* The brother of the overflow item also moves one step up,
2514 * but this does not affect bl_count[max_length]
2517 } while (overflow > 0);
2519 /* Now recompute all bit lengths, scanning in increasing frequency.
2520 * h is still equal to HEAP_SIZE. (It is simpler to reconstruct all
2521 * lengths instead of fixing only the wrong ones. This idea is taken
2522 * from 'ar' written by Haruhiko Okumura.)
2524 for (bits = max_length; bits != 0; bits--) {
2530 if (tree[m].Len != (unsigned) bits) {
2532 (stderr, "code %d bits %d->%d\n", m, tree[m].Len,
2536 (long) tree[m].Len) * (long) tree[m].Freq;
2537 tree[m].Len = (ush) bits;
2544 /* ===========================================================================
2545 * Generate the codes for a given tree and bit counts (which need not be
2547 * IN assertion: the array bl_count contains the bit length statistics for
2548 * the given tree and the field len is set for all tree elements.
2549 * OUT assertion: the field code is set for all tree elements of non
2552 local void gen_codes(tree, max_code)
2553 ct_data near *tree; /* the tree to decorate */
2554 int max_code; /* largest code with non zero frequency */
2556 ush next_code[MAX_BITS + 1]; /* next code value for each bit length */
2557 ush code = 0; /* running code value */
2558 int bits; /* bit index */
2559 int n; /* code index */
2561 /* The distribution counts are first used to generate the code values
2562 * without bit reversal.
2564 for (bits = 1; bits <= MAX_BITS; bits++) {
2565 next_code[bits] = code = (code + bl_count[bits - 1]) << 1;
2567 /* Check that the bit counts in bl_count are consistent. The last code
2570 Assert(code + bl_count[MAX_BITS] - 1 == (1 << MAX_BITS) - 1,
2571 "inconsistent bit counts");
2572 Tracev((stderr, "\ngen_codes: max_code %d ", max_code));
2574 for (n = 0; n <= max_code; n++) {
2575 int len = tree[n].Len;
2579 /* Now reverse the bits */
2580 tree[n].Code = bi_reverse(next_code[len]++, len);
2582 Tracec(tree != static_ltree,
2583 (stderr, "\nn %3d %c l %2d c %4x (%x) ", n,
2584 (isgraph(n) ? n : ' '), len, tree[n].Code,
2585 next_code[len] - 1));
2589 /* ===========================================================================
2590 * Construct one Huffman tree and assigns the code bit strings and lengths.
2591 * Update the total bit length for the current block.
2592 * IN assertion: the field freq is set for all tree elements.
2593 * OUT assertions: the fields len and code are set to the optimal bit length
2594 * and corresponding code. The length opt_len is updated; static_len is
2595 * also updated if stree is not null. The field max_code is set.
2597 local void build_tree(desc)
2598 tree_desc near *desc; /* the tree descriptor */
2600 ct_data near *tree = desc->dyn_tree;
2601 ct_data near *stree = desc->static_tree;
2602 int elems = desc->elems;
2603 int n, m; /* iterate over heap elements */
2604 int max_code = -1; /* largest code with non zero frequency */
2605 int node = elems; /* next internal node of the tree */
2607 /* Construct the initial heap, with least frequent element in
2608 * heap[SMALLEST]. The sons of heap[n] are heap[2*n] and heap[2*n+1].
2609 * heap[0] is not used.
2611 heap_len = 0, heap_max = HEAP_SIZE;
2613 for (n = 0; n < elems; n++) {
2614 if (tree[n].Freq != 0) {
2615 heap[++heap_len] = max_code = n;
2622 /* The pkzip format requires that at least one distance code exists,
2623 * and that at least one bit should be sent even if there is only one
2624 * possible code. So to avoid special checks later on we force at least
2625 * two codes of non zero frequency.
2627 while (heap_len < 2) {
2628 int new = heap[++heap_len] = (max_code < 2 ? ++max_code : 0);
2634 static_len -= stree[new].Len;
2635 /* new is 0 or 1 so it does not have extra bits */
2637 desc->max_code = max_code;
2639 /* The elements heap[heap_len/2+1 .. heap_len] are leaves of the tree,
2640 * establish sub-heaps of increasing lengths:
2642 for (n = heap_len / 2; n >= 1; n--)
2643 pqdownheap(tree, n);
2645 /* Construct the Huffman tree by repeatedly combining the least two
2649 pqremove(tree, n); /* n = node of least frequency */
2650 m = heap[SMALLEST]; /* m = node of next least frequency */
2652 heap[--heap_max] = n; /* keep the nodes sorted by frequency */
2653 heap[--heap_max] = m;
2655 /* Create a new node father of n and m */
2656 tree[node].Freq = tree[n].Freq + tree[m].Freq;
2657 depth[node] = (uch) (MAX(depth[n], depth[m]) + 1);
2658 tree[n].Dad = tree[m].Dad = (ush) node;
2660 if (tree == bl_tree) {
2661 fprintf(stderr, "\nnode %d(%d), sons %d(%d) %d(%d)",
2662 node, tree[node].Freq, n, tree[n].Freq, m,
2666 /* and insert the new node in the heap */
2667 heap[SMALLEST] = node++;
2668 pqdownheap(tree, SMALLEST);
2670 } while (heap_len >= 2);
2672 heap[--heap_max] = heap[SMALLEST];
2674 /* At this point, the fields freq and dad are set. We can now
2675 * generate the bit lengths.
2677 gen_bitlen((tree_desc near *) desc);
2679 /* The field len is now set, we can generate the bit codes */
2680 gen_codes((ct_data near *) tree, max_code);
2683 /* ===========================================================================
2684 * Scan a literal or distance tree to determine the frequencies of the codes
2685 * in the bit length tree. Updates opt_len to take into account the repeat
2686 * counts. (The contribution of the bit length codes will be added later
2687 * during the construction of bl_tree.)
2689 local void scan_tree(tree, max_code)
2690 ct_data near *tree; /* the tree to be scanned */
2691 int max_code; /* and its largest code of non zero frequency */
2693 int n; /* iterates over all tree elements */
2694 int prevlen = -1; /* last emitted length */
2695 int curlen; /* length of current code */
2696 int nextlen = tree[0].Len; /* length of next code */
2697 int count = 0; /* repeat count of the current code */
2698 int max_count = 7; /* max repeat count */
2699 int min_count = 4; /* min repeat count */
2702 max_count = 138, min_count = 3;
2703 tree[max_code + 1].Len = (ush) 0xffff; /* guard */
2705 for (n = 0; n <= max_code; n++) {
2707 nextlen = tree[n + 1].Len;
2708 if (++count < max_count && curlen == nextlen) {
2710 } else if (count < min_count) {
2711 bl_tree[curlen].Freq += count;
2712 } else if (curlen != 0) {
2713 if (curlen != prevlen)
2714 bl_tree[curlen].Freq++;
2715 bl_tree[REP_3_6].Freq++;
2716 } else if (count <= 10) {
2717 bl_tree[REPZ_3_10].Freq++;
2719 bl_tree[REPZ_11_138].Freq++;
2724 max_count = 138, min_count = 3;
2725 } else if (curlen == nextlen) {
2726 max_count = 6, min_count = 3;
2728 max_count = 7, min_count = 4;
2733 /* ===========================================================================
2734 * Send a literal or distance tree in compressed form, using the codes in
2737 local void send_tree(tree, max_code)
2738 ct_data near *tree; /* the tree to be scanned */
2739 int max_code; /* and its largest code of non zero frequency */
2741 int n; /* iterates over all tree elements */
2742 int prevlen = -1; /* last emitted length */
2743 int curlen; /* length of current code */
2744 int nextlen = tree[0].Len; /* length of next code */
2745 int count = 0; /* repeat count of the current code */
2746 int max_count = 7; /* max repeat count */
2747 int min_count = 4; /* min repeat count */
2749 /* tree[max_code+1].Len = -1; *//* guard already set */
2751 max_count = 138, min_count = 3;
2753 for (n = 0; n <= max_code; n++) {
2755 nextlen = tree[n + 1].Len;
2756 if (++count < max_count && curlen == nextlen) {
2758 } else if (count < min_count) {
2760 send_code(curlen, bl_tree);
2761 } while (--count != 0);
2763 } else if (curlen != 0) {
2764 if (curlen != prevlen) {
2765 send_code(curlen, bl_tree);
2768 Assert(count >= 3 && count <= 6, " 3_6?");
2769 send_code(REP_3_6, bl_tree);
2770 send_bits(count - 3, 2);
2772 } else if (count <= 10) {
2773 send_code(REPZ_3_10, bl_tree);
2774 send_bits(count - 3, 3);
2777 send_code(REPZ_11_138, bl_tree);
2778 send_bits(count - 11, 7);
2783 max_count = 138, min_count = 3;
2784 } else if (curlen == nextlen) {
2785 max_count = 6, min_count = 3;
2787 max_count = 7, min_count = 4;
2792 /* ===========================================================================
2793 * Construct the Huffman tree for the bit lengths and return the index in
2794 * bl_order of the last bit length code to send.
2796 local int build_bl_tree()
2798 int max_blindex; /* index of last bit length code of non zero freq */
2800 /* Determine the bit length frequencies for literal and distance trees */
2801 scan_tree((ct_data near *) dyn_ltree, l_desc.max_code);
2802 scan_tree((ct_data near *) dyn_dtree, d_desc.max_code);
2804 /* Build the bit length tree: */
2805 build_tree((tree_desc near *) (&bl_desc));
2806 /* opt_len now includes the length of the tree representations, except
2807 * the lengths of the bit lengths codes and the 5+5+4 bits for the counts.
2810 /* Determine the number of bit length codes to send. The pkzip format
2811 * requires that at least 4 bit length codes be sent. (appnote.txt says
2812 * 3 but the actual value used is 4.)
2814 for (max_blindex = BL_CODES - 1; max_blindex >= 3; max_blindex--) {
2815 if (bl_tree[bl_order[max_blindex]].Len != 0)
2818 /* Update opt_len to include the bit length tree and counts */
2819 opt_len += 3 * (max_blindex + 1) + 5 + 5 + 4;
2821 (stderr, "\ndyn trees: dyn %ld, stat %ld", opt_len,
2827 /* ===========================================================================
2828 * Send the header for a block using dynamic Huffman trees: the counts, the
2829 * lengths of the bit length codes, the literal tree and the distance tree.
2830 * IN assertion: lcodes >= 257, dcodes >= 1, blcodes >= 4.
2832 local void send_all_trees(lcodes, dcodes, blcodes)
2833 int lcodes, dcodes, blcodes; /* number of codes for each tree */
2835 int rank; /* index in bl_order */
2837 Assert(lcodes >= 257 && dcodes >= 1
2838 && blcodes >= 4, "not enough codes");
2839 Assert(lcodes <= L_CODES && dcodes <= D_CODES
2840 && blcodes <= BL_CODES, "too many codes");
2841 Tracev((stderr, "\nbl counts: "));
2842 send_bits(lcodes - 257, 5); /* not +255 as stated in appnote.txt */
2843 send_bits(dcodes - 1, 5);
2844 send_bits(blcodes - 4, 4); /* not -3 as stated in appnote.txt */
2845 for (rank = 0; rank < blcodes; rank++) {
2846 Tracev((stderr, "\nbl code %2d ", bl_order[rank]));
2847 send_bits(bl_tree[bl_order[rank]].Len, 3);
2849 Tracev((stderr, "\nbl tree: sent %ld", bits_sent));
2851 send_tree((ct_data near *) dyn_ltree, lcodes - 1); /* send the literal tree */
2852 Tracev((stderr, "\nlit tree: sent %ld", bits_sent));
2854 send_tree((ct_data near *) dyn_dtree, dcodes - 1); /* send the distance tree */
2855 Tracev((stderr, "\ndist tree: sent %ld", bits_sent));
2858 /* ===========================================================================
2859 * Determine the best encoding for the current block: dynamic trees, static
2860 * trees or store, and output the encoded block to the zip file. This function
2861 * returns the total compressed length for the file so far.
2863 ulg flush_block(buf, stored_len, eof)
2864 char *buf; /* input block, or NULL if too old */
2865 ulg stored_len; /* length of input block */
2866 int eof; /* true if this is the last block for a file */
2868 ulg opt_lenb, static_lenb; /* opt_len and static_len in bytes */
2869 int max_blindex; /* index of last bit length code of non zero freq */
2871 flag_buf[last_flags] = flags; /* Save the flags for the last 8 items */
2873 /* Check if the file is ascii or binary */
2874 if (*file_type == (ush) UNKNOWN)
2877 /* Construct the literal and distance trees */
2878 build_tree((tree_desc near *) (&l_desc));
2879 Tracev((stderr, "\nlit data: dyn %ld, stat %ld", opt_len, static_len));
2881 build_tree((tree_desc near *) (&d_desc));
2883 (stderr, "\ndist data: dyn %ld, stat %ld", opt_len,
2885 /* At this point, opt_len and static_len are the total bit lengths of
2886 * the compressed block data, excluding the tree representations.
2889 /* Build the bit length tree for the above two trees, and get the index
2890 * in bl_order of the last bit length code to send.
2892 max_blindex = build_bl_tree();
2894 /* Determine the best encoding. Compute first the block length in bytes */
2895 opt_lenb = (opt_len + 3 + 7) >> 3;
2896 static_lenb = (static_len + 3 + 7) >> 3;
2897 input_len += stored_len; /* for debugging only */
2901 "\nopt %lu(%lu) stat %lu(%lu) stored %lu lit %u dist %u ",
2902 opt_lenb, opt_len, static_lenb, static_len, stored_len,
2903 last_lit, last_dist));
2905 if (static_lenb <= opt_lenb)
2906 opt_lenb = static_lenb;
2908 /* If compression failed and this is the first and last block,
2909 * and if the zip file can be seeked (to rewrite the local header),
2910 * the whole file is transformed into a stored file:
2914 if (stored_len <= opt_lenb && eof && compressed_len == 0L
2917 /* Since LIT_BUFSIZE <= 2*WSIZE, the input data must be there: */
2918 if (buf == (char *) 0)
2919 error("block vanished");
2921 copy_block(buf, (unsigned) stored_len, 0); /* without header */
2922 compressed_len = stored_len << 3;
2923 *file_method = STORED;
2927 } else if (stored_len + 4 <= opt_lenb && buf != (char *) 0) {
2928 /* 4: two words for the lengths */
2930 /* The test buf != NULL is only necessary if LIT_BUFSIZE > WSIZE.
2931 * Otherwise we can't have processed more than WSIZE input bytes since
2932 * the last block flush, because compression would have been
2933 * successful. If LIT_BUFSIZE <= WSIZE, it is never too late to
2934 * transform a block into a stored block.
2936 send_bits((STORED_BLOCK << 1) + eof, 3); /* send block type */
2937 compressed_len = (compressed_len + 3 + 7) & ~7L;
2938 compressed_len += (stored_len + 4) << 3;
2940 copy_block(buf, (unsigned) stored_len, 1); /* with header */
2944 } else if (static_lenb == opt_lenb) {
2946 send_bits((STATIC_TREES << 1) + eof, 3);
2947 compress_block((ct_data near *) static_ltree,
2948 (ct_data near *) static_dtree);
2949 compressed_len += 3 + static_len;
2951 send_bits((DYN_TREES << 1) + eof, 3);
2952 send_all_trees(l_desc.max_code + 1, d_desc.max_code + 1,
2954 compress_block((ct_data near *) dyn_ltree,
2955 (ct_data near *) dyn_dtree);
2956 compressed_len += 3 + opt_len;
2958 Assert(compressed_len == bits_sent, "bad compressed size");
2962 Assert(input_len == isize, "bad input size");
2964 compressed_len += 7; /* align on byte boundary */
2966 Tracev((stderr, "\ncomprlen %lu(%lu) ", compressed_len >> 3,
2967 compressed_len - 7 * eof));
2969 return compressed_len >> 3;
2972 /* ===========================================================================
2973 * Save the match info and tally the frequency counts. Return true if
2974 * the current block must be flushed.
2976 int ct_tally(dist, lc)
2977 int dist; /* distance of matched string */
2978 int lc; /* match length-MIN_MATCH or unmatched char (if dist==0) */
2980 l_buf[last_lit++] = (uch) lc;
2982 /* lc is the unmatched char */
2983 dyn_ltree[lc].Freq++;
2985 /* Here, lc is the match length - MIN_MATCH */
2986 dist--; /* dist = match distance - 1 */
2987 Assert((ush) dist < (ush) MAX_DIST &&
2988 (ush) lc <= (ush) (MAX_MATCH - MIN_MATCH) &&
2989 (ush) d_code(dist) < (ush) D_CODES, "ct_tally: bad match");
2991 dyn_ltree[length_code[lc] + LITERALS + 1].Freq++;
2992 dyn_dtree[d_code(dist)].Freq++;
2994 d_buf[last_dist++] = (ush) dist;
2999 /* Output the flags if they fill a byte: */
3000 if ((last_lit & 7) == 0) {
3001 flag_buf[last_flags++] = flags;
3002 flags = 0, flag_bit = 1;
3004 /* Try to guess if it is profitable to stop the current block here */
3005 if ((last_lit & 0xfff) == 0) {
3006 /* Compute an upper bound for the compressed length */
3007 ulg out_length = (ulg) last_lit * 8L;
3008 ulg in_length = (ulg) strstart - block_start;
3011 for (dcode = 0; dcode < D_CODES; dcode++) {
3013 (ulg) dyn_dtree[dcode].Freq * (5L + extra_dbits[dcode]);
3018 "\nlast_lit %u, last_dist %u, in %ld, out ~%ld(%ld%%) ",
3019 last_lit, last_dist, in_length, out_length,
3020 100L - out_length * 100L / in_length));
3021 if (last_dist < last_lit / 2 && out_length < in_length / 2)
3024 return (last_lit == LIT_BUFSIZE - 1 || last_dist == DIST_BUFSIZE);
3025 /* We avoid equality with LIT_BUFSIZE because of wraparound at 64K
3026 * on 16 bit machines and because stored blocks are restricted to
3031 /* ===========================================================================
3032 * Send the block data compressed using the given Huffman trees
3034 local void compress_block(ltree, dtree)
3035 ct_data near *ltree; /* literal tree */
3036 ct_data near *dtree; /* distance tree */
3038 unsigned dist; /* distance of matched string */
3039 int lc; /* match length or unmatched char (if dist == 0) */
3040 unsigned lx = 0; /* running index in l_buf */
3041 unsigned dx = 0; /* running index in d_buf */
3042 unsigned fx = 0; /* running index in flag_buf */
3043 uch flag = 0; /* current flags */
3044 unsigned code; /* the code to send */
3045 int extra; /* number of extra bits to send */
3050 flag = flag_buf[fx++];
3052 if ((flag & 1) == 0) {
3053 send_code(lc, ltree); /* send a literal byte */
3054 Tracecv(isgraph(lc), (stderr, " '%c' ", lc));
3056 /* Here, lc is the match length - MIN_MATCH */
3057 code = length_code[lc];
3058 send_code(code + LITERALS + 1, ltree); /* send the length code */
3059 extra = extra_lbits[code];
3061 lc -= base_length[code];
3062 send_bits(lc, extra); /* send the extra length bits */
3065 /* Here, dist is the match distance - 1 */
3066 code = d_code(dist);
3067 Assert(code < D_CODES, "bad d_code");
3069 send_code(code, dtree); /* send the distance code */
3070 extra = extra_dbits[code];
3072 dist -= base_dist[code];
3073 send_bits(dist, extra); /* send the extra distance bits */
3075 } /* literal or match pair ? */
3077 } while (lx < last_lit);
3079 send_code(END_BLOCK, ltree);
3082 /* ===========================================================================
3083 * Set the file type to ASCII or BINARY, using a crude approximation:
3084 * binary if more than 20% of the bytes are <= 6 or >= 128, ascii otherwise.
3085 * IN assertion: the fields freq of dyn_ltree are set and the total of all
3086 * frequencies does not exceed 64K (to fit in an int on 16 bit machines).
3088 local void set_file_type()
3091 unsigned ascii_freq = 0;
3092 unsigned bin_freq = 0;
3095 bin_freq += dyn_ltree[n++].Freq;
3097 ascii_freq += dyn_ltree[n++].Freq;
3098 while (n < LITERALS)
3099 bin_freq += dyn_ltree[n++].Freq;
3100 *file_type = bin_freq > (ascii_freq >> 2) ? BINARY : ASCII;
3101 if (*file_type == BINARY && translate_eol) {
3102 warn("-l used on binary file", "");
3106 /* util.c -- utility functions for gzip support
3107 * Copyright (C) 1992-1993 Jean-loup Gailly
3108 * This is free software; you can redistribute it and/or modify it under the
3109 * terms of the GNU General Public License, see the file COPYING.
3114 #include <sys/types.h>
3116 #ifdef HAVE_UNISTD_H
3117 # include <unistd.h>
3123 #if defined(STDC_HEADERS) || !defined(NO_STDLIB_H)
3124 # include <stdlib.h>
3129 /* ===========================================================================
3130 * Copy input to output unchanged: zcat == cat with --force.
3131 * IN assertion: insize bytes have already been read in inbuf.
3134 int in, out; /* input and output file descriptors */
3137 while (insize != 0 && (int) insize != EOF) {
3138 write_buf(out, (char *) inbuf, insize);
3139 bytes_out += insize;
3140 insize = read(in, (char *) inbuf, INBUFSIZ);
3142 if ((int) insize == EOF && errno != 0) {
3145 bytes_in = bytes_out;
3149 /* ========================================================================
3150 * Put string s in lower case, return s.
3157 for (t = s; *t; t++)
3162 #if defined(NO_STRING_H) && !defined(STDC_HEADERS)
3164 /* Provide missing strspn and strcspn functions. */
3170 int strspn OF((const char *s, const char *accept));
3171 int strcspn OF((const char *s, const char *reject));
3173 /* ========================================================================
3174 * Return the length of the maximum initial segment
3175 * of s which contains only characters in accept.
3177 int strspn(s, accept)
3181 register const char *p;
3182 register const char *a;
3183 register int count = 0;
3185 for (p = s; *p != '\0'; ++p) {
3186 for (a = accept; *a != '\0'; ++a) {
3197 /* ========================================================================
3198 * Return the length of the maximum inital segment of s
3199 * which contains no characters from reject.
3201 int strcspn(s, reject)
3205 register int count = 0;
3207 while (*s != '\0') {
3208 if (strchr(reject, *s++) != NULL)
3215 #endif /* NO_STRING_H */
3217 /* ========================================================================
3218 * Add an environment variable (if any) before argv, and update argc.
3219 * Return the expanded environment variable to be freed later, or NULL
3220 * if no options were added to argv.
3222 #define SEPARATOR " \t" /* separators in env variable */
3224 char *add_envopt(argcp, argvp, env)
3225 int *argcp; /* pointer to argc */
3226 char ***argvp; /* pointer to argv */
3227 char *env; /* name of environment variable */
3229 char *p; /* running pointer through env variable */
3230 char **oargv; /* runs through old argv array */
3231 char **nargv; /* runs through new argv array */
3232 int oargc = *argcp; /* old argc */
3233 int nargc = 0; /* number of arguments in env variable */
3235 env = (char *) getenv(env);
3239 p = (char *) xmalloc(strlen(env) + 1);
3240 env = strcpy(p, env); /* keep env variable intact */
3242 for (p = env; *p; nargc++) { /* move through env */
3243 p += strspn(p, SEPARATOR); /* skip leading separators */
3247 p += strcspn(p, SEPARATOR); /* find end of word */
3249 *p++ = '\0'; /* mark it */
3256 /* Allocate the new argv array, with an extra element just in case
3257 * the original arg list did not end with a NULL.
3259 nargv = (char **) calloc(*argcp + 1, sizeof(char *));
3262 error("out of memory");
3266 /* Copy the program name first */
3269 *(nargv++) = *(oargv++);
3271 /* Then copy the environment args */
3272 for (p = env; nargc > 0; nargc--) {
3273 p += strspn(p, SEPARATOR); /* skip separators */
3274 *(nargv++) = p; /* store start */
3275 while (*p++); /* skip over word */
3278 /* Finally copy the old args and add a NULL (usual convention) */
3280 *(nargv++) = *(oargv++);
3285 /* ========================================================================
3286 * Display compression ratio on the given stream on 6 characters.
3288 void display_ratio(num, den, file)
3293 long ratio; /* 1000 times the compression ratio */
3296 ratio = 0; /* no compression */
3297 } else if (den < 2147483L) { /* (2**31 -1)/1000 */
3298 ratio = 1000L * num / den;
3300 ratio = num / (den / 1000L);
3308 fprintf(file, "%2ld.%1ld%%", ratio / 10L, ratio % 10L);
3312 /* zip.c -- compress files to the gzip or pkzip format
3313 * Copyright (C) 1992-1993 Jean-loup Gailly
3314 * This is free software; you can redistribute it and/or modify it under the
3315 * terms of the GNU General Public License, see the file COPYING.
3319 #include <sys/types.h>
3321 #ifdef HAVE_UNISTD_H
3322 # include <unistd.h>
3328 local ulg crc; /* crc on uncompressed file data */
3329 long header_bytes; /* number of bytes in gzip header */
3331 /* ===========================================================================
3332 * Deflate in to out.
3333 * IN assertions: the input and output buffers are cleared.
3334 * The variables time_stamp and save_orig_name are initialized.
3337 int in, out; /* input and output file descriptors */
3339 uch flags = 0; /* general purpose bit flags */
3340 ush attr = 0; /* ascii/binary flag */
3341 ush deflate_flags = 0; /* pkzip -es, -en or -ex equivalent */
3347 /* Write the header to the gzip file. See algorithm.doc for the format */
3351 put_byte(GZIP_MAGIC[0]); /* magic header */
3352 put_byte(GZIP_MAGIC[1]);
3353 put_byte(DEFLATED); /* compression method */
3355 put_byte(flags); /* general flags */
3356 put_long(time_stamp);
3358 /* Write deflated file to zip file */
3362 ct_init(&attr, &method);
3363 lm_init(&deflate_flags);
3365 put_byte((uch) deflate_flags); /* extra flags */
3366 put_byte(OS_CODE); /* OS identifier */
3368 header_bytes = (long) outcnt;
3372 /* Write the crc and uncompressed size */
3375 header_bytes += 2 * sizeof(long);
3382 /* ===========================================================================
3383 * Read a new buffer from the current input file, perform end-of-line
3384 * translation, and update the crc and input file size.
3385 * IN assertion: size >= 2 (for end-of-line translation)
3387 int file_read(buf, size)
3393 Assert(insize == 0, "inbuf not empty");
3395 len = read(ifd, buf, size);
3396 if (len == (unsigned) (-1) || len == 0)
3399 crc = updcrc((uch *) buf, len);
projects / oweals / busybox.git / blob