1 /* vi: set sw=4 ts=4: */
3 * Gzip implementation for busybox
5 * Based on GNU gzip Copyright (C) 1992-1993 Jean-loup Gailly.
7 * Originally adjusted for busybox by Charles P. Wright <cpw@unix.asb.com>
8 * "this is a stripped down version of gzip I put into busybox, it does
9 * only standard in to standard out with -9 compression. It also requires
10 * the zcat module for some important functions."
12 * Adjusted further by Erik Andersen <andersen@codepoet.org> to support
13 * files as well as stdin/stdout, and to generally behave itself wrt
14 * command line handling.
16 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
19 /* big objects in bss:
21 * 00000074 b base_length
22 * 00000078 b base_dist
23 * 00000078 b static_dtree
25 * 000000f4 b dyn_dtree
26 * 00000100 b length_code
27 * 00000200 b dist_code
31 * 00000480 b static_ltree
32 * 000008f4 b dyn_ltree
35 /* TODO: full support for -v for DESKTOP
36 * "/usr/bin/gzip -v a bogus aa" should say:
37 a: 85.1% -- replaced with a.gz
38 gzip: bogus: No such file or directory
39 aa: 85.1% -- replaced with aa.gz
45 /* ===========================================================================
48 /* Diagnostic functions */
50 # define Assert(cond,msg) {if(!(cond)) bb_error_msg(msg);}
51 # define Trace(x) fprintf x
52 # define Tracev(x) {if (verbose) fprintf x ;}
53 # define Tracevv(x) {if (verbose > 1) fprintf x ;}
54 # define Tracec(c,x) {if (verbose && (c)) fprintf x ;}
55 # define Tracecv(c,x) {if (verbose > 1 && (c)) fprintf x ;}
57 # define Assert(cond,msg)
66 /* ===========================================================================
70 //// /* Compression methods (see algorithm.doc) */
71 //// /* Only STORED and DEFLATED are supported by this BusyBox module */
73 //// /* methods 4 to 7 reserved */
74 //// #define DEFLATED 8
78 # define INBUFSIZ 0x2000 /* input buffer size */
80 # define INBUFSIZ 0x8000 /* input buffer size */
86 # define OUTBUFSIZ 8192 /* output buffer size */
88 # define OUTBUFSIZ 16384 /* output buffer size */
94 # define DIST_BUFSIZE 0x2000 /* buffer for distances, see trees.c */
96 # define DIST_BUFSIZE 0x8000 /* buffer for distances, see trees.c */
101 #define ASCII_FLAG 0x01 /* bit 0 set: file probably ascii text */
102 #define CONTINUATION 0x02 /* bit 1 set: continuation of multi-part gzip file */
103 #define EXTRA_FIELD 0x04 /* bit 2 set: extra field present */
104 #define ORIG_NAME 0x08 /* bit 3 set: original file name present */
105 #define COMMENT 0x10 /* bit 4 set: file comment present */
106 #define RESERVED 0xC0 /* bit 6,7: reserved */
108 /* internal file attribute */
109 #define UNKNOWN 0xffff
114 # define WSIZE 0x8000 /* window size--must be a power of two, and */
115 #endif /* at least 32K for zip's deflate method */
118 #define MAX_MATCH 258
119 /* The minimum and maximum match lengths */
121 #define MIN_LOOKAHEAD (MAX_MATCH+MIN_MATCH+1)
122 /* Minimum amount of lookahead, except at the end of the input file.
123 * See deflate.c for comments about the MIN_MATCH+1.
126 #define MAX_DIST (WSIZE-MIN_LOOKAHEAD)
127 /* In order to simplify the code, particularly on 16 bit machines, match
128 * distances are limited to MAX_DIST instead of WSIZE.
132 # define MAX_PATH_LEN 1024 /* max pathname length */
135 #define seekable() 0 /* force sequential output */
136 #define translate_eol 0 /* no option -a yet */
141 #define INIT_BITS 9 /* Initial number of bits per code */
143 #define BIT_MASK 0x1f /* Mask for 'number of compression bits' */
144 /* Mask 0x20 is reserved to mean a fourth header byte, and 0x40 is free.
145 * It's a pity that old uncompress does not check bit 0x20. That makes
146 * extension of the format actually undesirable because old compress
147 * would just crash on the new format instead of giving a meaningful
148 * error message. It does check the number of bits, but it's more
149 * helpful to say "unsupported format, get a new version" than
150 * "can only handle 16 bits".
154 # define MAX_SUFFIX MAX_EXT_CHARS
156 # define MAX_SUFFIX 30
160 /* ===========================================================================
161 * Compile with MEDIUM_MEM to reduce the memory requirements or
162 * with SMALL_MEM to use as little memory as possible. Use BIG_MEM if the
163 * entire input file can be held in memory (not possible on 16 bit systems).
164 * Warning: defining these symbols affects HASH_BITS (see below) and thus
165 * affects the compression ratio. The compressed output
166 * is still correct, and might even be smaller in some cases.
170 # define HASH_BITS 13 /* Number of bits used to hash strings */
173 # define HASH_BITS 14
176 # define HASH_BITS 15
177 /* For portability to 16 bit machines, do not use values above 15. */
180 #define HASH_SIZE (unsigned)(1<<HASH_BITS)
181 #define HASH_MASK (HASH_SIZE-1)
182 #define WMASK (WSIZE-1)
183 /* HASH_SIZE and WSIZE must be powers of two */
185 # define TOO_FAR 4096
187 /* Matches of length 3 are discarded if their distance exceeds TOO_FAR */
190 /* ===========================================================================
191 * These types are not really 'char', 'short' and 'long'
194 typedef uint16_t ush;
195 typedef uint32_t ulg;
199 typedef unsigned IPos;
202 WINDOW_SIZE = 2 * WSIZE,
203 /* window size, 2*WSIZE except for MMAP or BIG_MEM, where it is the
204 * input file length plus MIN_LOOKAHEAD.
207 max_chain_length = 4096,
208 /* To speed up deflation, hash chains are never searched beyond this length.
209 * A higher limit improves compression ratio but degrades the speed.
212 max_lazy_match = 258,
213 /* Attempt to find a better match only when the current match is strictly
214 * smaller than this value. This mechanism is used only for compression
218 max_insert_length = max_lazy_match,
219 /* Insert new strings in the hash table only if the match length
220 * is not greater than this length. This saves time but degrades compression.
221 * max_insert_length is used only for compression levels <= 3.
225 /* Use a faster search when the previous match is longer than this */
227 /* Values for max_lazy_match, good_match and max_chain_length, depending on
228 * the desired pack level (0..9). The values given below have been tuned to
229 * exclude worst case performance for pathological files. Better values may be
230 * found for specific files.
233 nice_match = 258, /* Stop searching when current match exceeds this */
234 /* Note: the deflate() code requires max_lazy >= MIN_MATCH and max_chain >= 4
235 * For deflate_fast() (levels <= 3) good is ignored and lazy has a different
243 /* A Pos is an index in the character window. We use short instead of int to
244 * save space in the various tables. IPos is used only for parameter passing.
248 /* window position at the beginning of the current output block. Gets
249 * negative when the window is moved backwards.
251 unsigned ins_h; /* hash index of string to be inserted */
253 #define H_SHIFT ((HASH_BITS+MIN_MATCH-1) / MIN_MATCH)
254 /* Number of bits by which ins_h and del_h must be shifted at each
255 * input step. It must be such that after MIN_MATCH steps, the oldest
256 * byte no longer takes part in the hash key, that is:
257 * H_SHIFT * MIN_MATCH >= HASH_BITS
260 unsigned prev_length;
262 /* Length of the best match at previous step. Matches not greater than this
263 * are discarded. This is used in the lazy match evaluation.
266 unsigned strstart; /* start of string to insert */
267 unsigned match_start; /* start of matching string */
268 unsigned lookahead; /* number of valid bytes ahead in window */
269 smallint eofile; /* flag set at end of input file */
271 /* ===========================================================================
273 #define DECLARE(type, array, size) \
275 #define ALLOC(type, array, size) \
276 array = xzalloc((size_t)(((size)+1L)/2) * 2*sizeof(type));
277 #define FREE(array) \
278 do { free(array); array = NULL; } while (0)
282 /* buffer for literals or lengths */
283 /* DECLARE(uch, l_buf, LIT_BUFSIZE); */
284 DECLARE(uch, l_buf, INBUFSIZ);
286 DECLARE(ush, d_buf, DIST_BUFSIZE);
287 DECLARE(uch, outbuf, OUTBUFSIZ);
289 /* Sliding window. Input bytes are read into the second half of the window,
290 * and move to the first half later to keep a dictionary of at least WSIZE
291 * bytes. With this organization, matches are limited to a distance of
292 * WSIZE-MAX_MATCH bytes, but this ensures that IO is always
293 * performed with a length multiple of the block size. Also, it limits
294 * the window size to 64K, which is quite useful on MSDOS.
295 * To do: limit the window size to WSIZE+BSZ if SMALL_MEM (the code would
296 * be less efficient).
298 DECLARE(uch, window, 2L * WSIZE);
300 /* Link to older string with same hash index. To limit the size of this
301 * array to 64K, this link is maintained only for the last 32K strings.
302 * An index in this array is thus a window index modulo 32K.
304 /* DECLARE(Pos, prev, WSIZE); */
305 DECLARE(ush, prev, 1L << BITS);
307 /* Heads of the hash chains or 0. */
308 /* DECLARE(Pos, head, 1<<HASH_BITS); */
309 #define head (G1.prev + WSIZE) /* hash head (see deflate.c) */
312 /* number of input bytes */
313 ulg isize; /* only 32 bits stored in .gz file */
315 //// int method = DEFLATED; /* compression method */
316 //## int exit_code; /* program exit code */
318 /* original time stamp (modification time) */
319 ulg time_stamp; /* only 32 bits stored in .gz file */
321 int ifd; /* input file descriptor */
322 int ofd; /* output file descriptor */
324 unsigned insize; /* valid bytes in l_buf */
326 unsigned outcnt; /* bytes in output buffer */
328 uint32_t *crc_32_tab;
331 /* ===========================================================================
332 * Local data used by the "bit string" routines.
335 unsigned short bi_buf;
337 /* Output buffer. bits are inserted starting at the bottom (least significant
342 #define BUF_SIZE (8 * sizeof(G1.bi_buf))
343 /* Number of bits used within bi_buf. (bi_buf might be implemented on
344 * more than 16 bits on some systems.)
349 /* Current input function. Set to mem_read for in-memory compression */
352 ulg bits_sent; /* bit length of the compressed data */
355 uint32_t crc; /* shift register contents */
361 /* ===========================================================================
362 * Write the output buffer outbuf[0..outcnt-1] and update bytes_out.
363 * (used for the compressed data only)
365 static void flush_outbuf(void)
370 xwrite(G1.ofd, (char *) G1.outbuf, G1.outcnt);
375 /* ===========================================================================
377 /* put_8bit is used for the compressed output */
378 #define put_8bit(c) \
380 G1.outbuf[G1.outcnt++] = (c); \
381 if (G1.outcnt == OUTBUFSIZ) flush_outbuf(); \
384 /* Output a 16 bit value, lsb first */
385 static void put_16bit(ush w)
387 if (G1.outcnt < OUTBUFSIZ - 2) {
388 G1.outbuf[G1.outcnt++] = w;
389 G1.outbuf[G1.outcnt++] = w >> 8;
396 static void put_32bit(ulg n)
402 /* ===========================================================================
403 * Clear input and output buffers
405 static void clear_bufs(void)
415 /* ===========================================================================
416 * Run a set of bytes through the crc shift register. If s is a NULL
417 * pointer, then initialize the crc shift register contents instead.
418 * Return the current crc in either case.
420 static uint32_t updcrc(uch * s, unsigned n)
424 c = G1.crc_32_tab[(uch)(c ^ *s++)] ^ (c >> 8);
432 /* ===========================================================================
433 * Read a new buffer from the current input file, perform end-of-line
434 * translation, and update the crc and input file size.
435 * IN assertion: size >= 2 (for end-of-line translation)
437 static unsigned file_read(void *buf, unsigned size)
441 Assert(G1.insize == 0, "l_buf not empty");
443 len = safe_read(G1.ifd, buf, size);
444 if (len == (unsigned)(-1) || len == 0)
453 /* ===========================================================================
454 * Send a value on a given number of bits.
455 * IN assertion: length <= 16 and value fits in length bits.
457 static void send_bits(int value, int length)
460 Tracev((stderr, " l %2d v %4x ", length, value));
461 Assert(length > 0 && length <= 15, "invalid length");
462 G1.bits_sent += length;
464 /* If not enough room in bi_buf, use (valid) bits from bi_buf and
465 * (16 - bi_valid) bits from value, leaving (width - (16-bi_valid))
466 * unused bits in value.
468 if (G1.bi_valid > (int) BUF_SIZE - length) {
469 G1.bi_buf |= (value << G1.bi_valid);
470 put_16bit(G1.bi_buf);
471 G1.bi_buf = (ush) value >> (BUF_SIZE - G1.bi_valid);
472 G1.bi_valid += length - BUF_SIZE;
474 G1.bi_buf |= value << G1.bi_valid;
475 G1.bi_valid += length;
480 /* ===========================================================================
481 * Reverse the first len bits of a code, using straightforward code (a faster
482 * method would use a table)
483 * IN assertion: 1 <= len <= 15
485 static unsigned bi_reverse(unsigned code, int len)
491 if (--len <= 0) return res;
498 /* ===========================================================================
499 * Write out any remaining bits in an incomplete byte.
501 static void bi_windup(void)
503 if (G1.bi_valid > 8) {
504 put_16bit(G1.bi_buf);
505 } else if (G1.bi_valid > 0) {
511 G1.bits_sent = (G1.bits_sent + 7) & ~7;
516 /* ===========================================================================
517 * Copy a stored block to the zip file, storing first the length and its
518 * one's complement if requested.
520 static void copy_block(char *buf, unsigned len, int header)
522 bi_windup(); /* align on byte boundary */
528 G1.bits_sent += 2 * 16;
532 G1.bits_sent += (ulg) len << 3;
540 /* ===========================================================================
541 * Fill the window when the lookahead becomes insufficient.
542 * Updates strstart and lookahead, and sets eofile if end of input file.
543 * IN assertion: lookahead < MIN_LOOKAHEAD && strstart + lookahead > 0
544 * OUT assertions: at least one byte has been read, or eofile is set;
545 * file reads are performed for at least two bytes (required for the
546 * translate_eol option).
548 static void fill_window(void)
551 unsigned more = WINDOW_SIZE - G1.lookahead - G1.strstart;
552 /* Amount of free space at the end of the window. */
554 /* If the window is almost full and there is insufficient lookahead,
555 * move the upper half to the lower one to make room in the upper half.
557 if (more == (unsigned) -1) {
558 /* Very unlikely, but possible on 16 bit machine if strstart == 0
559 * and lookahead == 1 (input done one byte at time)
562 } else if (G1.strstart >= WSIZE + MAX_DIST) {
563 /* By the IN assertion, the window is not empty so we can't confuse
564 * more == 0 with more == 64K on a 16 bit machine.
566 Assert(WINDOW_SIZE == 2 * WSIZE, "no sliding with BIG_MEM");
568 memcpy(G1.window, G1.window + WSIZE, WSIZE);
569 G1.match_start -= WSIZE;
570 G1.strstart -= WSIZE; /* we now have strstart >= MAX_DIST: */
572 G1.block_start -= WSIZE;
574 for (n = 0; n < HASH_SIZE; n++) {
576 head[n] = (Pos) (m >= WSIZE ? m - WSIZE : 0);
578 for (n = 0; n < WSIZE; n++) {
580 G1.prev[n] = (Pos) (m >= WSIZE ? m - WSIZE : 0);
581 /* If n is not on any hash chain, prev[n] is garbage but
582 * its value will never be used.
587 /* At this point, more >= 2 */
589 n = file_read(G1.window + G1.strstart + G1.lookahead, more);
590 if (n == 0 || n == (unsigned) -1) {
599 /* ===========================================================================
600 * Set match_start to the longest match starting at the given string and
601 * return its length. Matches shorter or equal to prev_length are discarded,
602 * in which case the result is equal to prev_length and match_start is
604 * IN assertions: cur_match is the head of the hash chain for the current
605 * string (strstart) and its distance is <= MAX_DIST, and prev_length >= 1
608 /* For MSDOS, OS/2 and 386 Unix, an optimized version is in match.asm or
609 * match.s. The code is functionally equivalent, so you can use the C version
612 static int longest_match(IPos cur_match)
614 unsigned chain_length = max_chain_length; /* max hash chain length */
615 uch *scan = G1.window + G1.strstart; /* current string */
616 uch *match; /* matched string */
617 int len; /* length of current match */
618 int best_len = G1.prev_length; /* best match length so far */
619 IPos limit = G1.strstart > (IPos) MAX_DIST ? G1.strstart - (IPos) MAX_DIST : 0;
620 /* Stop when cur_match becomes <= limit. To simplify the code,
621 * we prevent matches with the string of window index 0.
624 /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16.
625 * It is easy to get rid of this optimization if necessary.
627 #if HASH_BITS < 8 || MAX_MATCH != 258
628 # error Code too clever
630 uch *strend = G1.window + G1.strstart + MAX_MATCH;
631 uch scan_end1 = scan[best_len - 1];
632 uch scan_end = scan[best_len];
634 /* Do not waste too much time if we already have a good match: */
635 if (G1.prev_length >= good_match) {
638 Assert(G1.strstart <= WINDOW_SIZE - MIN_LOOKAHEAD, "insufficient lookahead");
641 Assert(cur_match < G1.strstart, "no future");
642 match = G1.window + cur_match;
644 /* Skip to next match if the match length cannot increase
645 * or if the match length is less than 2:
647 if (match[best_len] != scan_end ||
648 match[best_len - 1] != scan_end1 ||
649 *match != *scan || *++match != scan[1])
652 /* The check at best_len-1 can be removed because it will be made
653 * again later. (This heuristic is not always a win.)
654 * It is not necessary to compare scan[2] and match[2] since they
655 * are always equal when the other bytes match, given that
656 * the hash keys are equal and that HASH_BITS >= 8.
660 /* We check for insufficient lookahead only every 8th comparison;
661 * the 256th check will be made at strstart+258.
664 } while (*++scan == *++match && *++scan == *++match &&
665 *++scan == *++match && *++scan == *++match &&
666 *++scan == *++match && *++scan == *++match &&
667 *++scan == *++match && *++scan == *++match && scan < strend);
669 len = MAX_MATCH - (int) (strend - scan);
670 scan = strend - MAX_MATCH;
672 if (len > best_len) {
673 G1.match_start = cur_match;
675 if (len >= nice_match)
677 scan_end1 = scan[best_len - 1];
678 scan_end = scan[best_len];
680 } while ((cur_match = G1.prev[cur_match & WMASK]) > limit
681 && --chain_length != 0);
688 /* ===========================================================================
689 * Check that the match at match_start is indeed a match.
691 static void check_match(IPos start, IPos match, int length)
693 /* check that the match is indeed a match */
694 if (memcmp(G1.window + match, G1.window + start, length) != 0) {
695 bb_error_msg(" start %d, match %d, length %d", start, match, length);
696 bb_error_msg("invalid match");
699 bb_error_msg("\\[%d,%d]", start - match, length);
701 putc(G1.window[start++], stderr);
702 } while (--length != 0);
706 # define check_match(start, match, length) ((void)0)
710 /* trees.c -- output deflated data using Huffman coding
711 * Copyright (C) 1992-1993 Jean-loup Gailly
712 * This is free software; you can redistribute it and/or modify it under the
713 * terms of the GNU General Public License, see the file COPYING.
717 * Encode various sets of source values using variable-length
721 * The PKZIP "deflation" process uses several Huffman trees. The more
722 * common source values are represented by shorter bit sequences.
724 * Each code tree is stored in the ZIP file in a compressed form
725 * which is itself a Huffman encoding of the lengths of
726 * all the code strings (in ascending order by source values).
727 * The actual code strings are reconstructed from the lengths in
728 * the UNZIP process, as described in the "application note"
729 * (APPNOTE.TXT) distributed as part of PKWARE's PKZIP program.
733 * Data Compression: Techniques and Applications, pp. 53-55.
734 * Lifetime Learning Publications, 1985. ISBN 0-534-03418-7.
737 * Data Compression: Methods and Theory, pp. 49-50.
738 * Computer Science Press, 1988. ISBN 0-7167-8156-5.
742 * Addison-Wesley, 1983. ISBN 0-201-06672-6.
745 * void ct_init() //// ush *attr, int *methodp)
746 * Allocate the match buffer, initialize the various tables and save
747 * the location of the internal file attribute (ascii/binary) and
748 * method (DEFLATE/STORE)
750 * void ct_tally(int dist, int lc);
751 * Save the match info and tally the frequency counts.
753 * ulg flush_block(char *buf, ulg stored_len, int eof)
754 * Determine the best encoding for the current block: dynamic trees,
755 * static trees or store, and output the encoded block to the zip
756 * file. Returns the total compressed length for the file so far.
760 /* All codes must not exceed MAX_BITS bits */
762 #define MAX_BL_BITS 7
763 /* Bit length codes must not exceed MAX_BL_BITS bits */
765 #define LENGTH_CODES 29
766 /* number of length codes, not counting the special END_BLOCK code */
769 /* number of literal bytes 0..255 */
771 #define END_BLOCK 256
772 /* end of block literal code */
774 #define L_CODES (LITERALS+1+LENGTH_CODES)
775 /* number of Literal or Length codes, including the END_BLOCK code */
778 /* number of distance codes */
781 /* number of codes used to transfer the bit lengths */
783 typedef uch extra_bits_t;
785 /* extra bits for each length code */
786 static const extra_bits_t extra_lbits[LENGTH_CODES]= {
787 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4,
791 /* extra bits for each distance code */
792 static const extra_bits_t extra_dbits[D_CODES] = {
793 0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6, 7, 7, 8, 8, 9, 9,
794 10, 10, 11, 11, 12, 12, 13, 13
797 /* extra bits for each bit length code */
798 static const extra_bits_t extra_blbits[BL_CODES] = {
799 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 3, 7 };
801 /* number of codes at each bit length for an optimal tree */
802 static const uch bl_order[BL_CODES] = {
803 16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15 };
805 #define STORED_BLOCK 0
806 #define STATIC_TREES 1
808 /* The three kinds of block type */
812 # define LIT_BUFSIZE 0x2000
815 # define LIT_BUFSIZE 0x4000
817 # define LIT_BUFSIZE 0x8000
822 # define DIST_BUFSIZE LIT_BUFSIZE
824 /* Sizes of match buffers for literals/lengths and distances. There are
825 * 4 reasons for limiting LIT_BUFSIZE to 64K:
826 * - frequencies can be kept in 16 bit counters
827 * - if compression is not successful for the first block, all input data is
828 * still in the window so we can still emit a stored block even when input
829 * comes from standard input. (This can also be done for all blocks if
830 * LIT_BUFSIZE is not greater than 32K.)
831 * - if compression is not successful for a file smaller than 64K, we can
832 * even emit a stored file instead of a stored block (saving 5 bytes).
833 * - creating new Huffman trees less frequently may not provide fast
834 * adaptation to changes in the input data statistics. (Take for
835 * example a binary file with poorly compressible code followed by
836 * a highly compressible string table.) Smaller buffer sizes give
837 * fast adaptation but have of course the overhead of transmitting trees
839 * - I can't count above 4
840 * The current code is general and allows DIST_BUFSIZE < LIT_BUFSIZE (to save
841 * memory at the expense of compression). Some optimizations would be possible
842 * if we rely on DIST_BUFSIZE == LIT_BUFSIZE.
845 /* repeat previous bit length 3-6 times (2 bits of repeat count) */
847 /* repeat a zero length 3-10 times (3 bits of repeat count) */
848 #define REPZ_11_138 18
849 /* repeat a zero length 11-138 times (7 bits of repeat count) */
851 /* ===========================================================================
853 /* Data structure describing a single value and its code string. */
854 typedef struct ct_data {
856 ush freq; /* frequency count */
857 ush code; /* bit string */
860 ush dad; /* father node in Huffman tree */
861 ush len; /* length of bit string */
870 #define HEAP_SIZE (2*L_CODES + 1)
871 /* maximum heap size */
873 typedef struct tree_desc {
874 ct_data *dyn_tree; /* the dynamic tree */
875 ct_data *static_tree; /* corresponding static tree or NULL */
876 const extra_bits_t *extra_bits; /* extra bits for each code or NULL */
877 int extra_base; /* base index for extra_bits */
878 int elems; /* max number of elements in the tree */
879 int max_length; /* max bit length for the codes */
880 int max_code; /* largest code with non zero frequency */
885 ush heap[HEAP_SIZE]; /* heap used to build the Huffman trees */
886 int heap_len; /* number of elements in the heap */
887 int heap_max; /* element of largest frequency */
889 /* The sons of heap[n] are heap[2*n] and heap[2*n+1]. heap[0] is not used.
890 * The same heap array is used to build all trees.
893 ct_data dyn_ltree[HEAP_SIZE]; /* literal and length tree */
894 ct_data dyn_dtree[2 * D_CODES + 1]; /* distance tree */
896 ct_data static_ltree[L_CODES + 2];
898 /* The static literal tree. Since the bit lengths are imposed, there is no
899 * need for the L_CODES extra codes used during heap construction. However
900 * The codes 286 and 287 are needed to build a canonical tree (see ct_init
904 ct_data static_dtree[D_CODES];
906 /* The static distance tree. (Actually a trivial tree since all codes use
910 ct_data bl_tree[2 * BL_CODES + 1];
912 /* Huffman tree for the bit lengths */
918 ush bl_count[MAX_BITS + 1];
920 /* The lengths of the bit length codes are sent in order of decreasing
921 * probability, to avoid transmitting the lengths for unused bit length codes.
924 uch depth[2 * L_CODES + 1];
926 /* Depth of each subtree used as tie breaker for trees of equal frequency */
928 uch length_code[MAX_MATCH - MIN_MATCH + 1];
930 /* length code for each normalized match length (0 == MIN_MATCH) */
934 /* distance codes. The first 256 values correspond to the distances
935 * 3 .. 258, the last 256 values correspond to the top 8 bits of
936 * the 15 bit distances.
939 int base_length[LENGTH_CODES];
941 /* First normalized length for each code (0 = MIN_MATCH) */
943 int base_dist[D_CODES];
945 /* First normalized distance for each code (0 = distance of 1) */
947 uch flag_buf[LIT_BUFSIZE / 8];
949 /* flag_buf is a bit array distinguishing literals from lengths in
950 * l_buf, thus indicating the presence or absence of a distance.
953 unsigned last_lit; /* running index in l_buf */
954 unsigned last_dist; /* running index in d_buf */
955 unsigned last_flags; /* running index in flag_buf */
956 uch flags; /* current flags not yet saved in flag_buf */
957 uch flag_bit; /* current bit used in flags */
959 /* bits are filled in flags starting at bit 0 (least significant).
960 * Note: these flags are overkill in the current code since we don't
961 * take advantage of DIST_BUFSIZE == LIT_BUFSIZE.
964 ulg opt_len; /* bit length of current block with optimal trees */
965 ulg static_len; /* bit length of current block with static trees */
967 ulg compressed_len; /* total bit length of compressed file */
969 //// ush *file_type; /* pointer to UNKNOWN, BINARY or ASCII */
970 //// int *file_method; /* pointer to DEFLATE or STORE */
974 static struct G2 *G2ptr;
978 G2.dyn_ltree, G2.static_ltree, extra_lbits,
979 LITERALS + 1, L_CODES, MAX_BITS, 0
982 G2.dyn_dtree, G2.static_dtree, extra_dbits,
983 0, D_CODES, MAX_BITS, 0
986 G2.bl_tree, NULL, extra_blbits,
987 0, BL_CODES, MAX_BL_BITS, 0
993 /* ===========================================================================
995 static void gen_codes(ct_data * tree, int max_code);
996 static void build_tree(tree_desc * desc);
997 static void scan_tree(ct_data * tree, int max_code);
998 static void send_tree(ct_data * tree, int max_code);
999 static int build_bl_tree(void);
1000 static void send_all_trees(int lcodes, int dcodes, int blcodes);
1001 static void compress_block(ct_data * ltree, ct_data * dtree);
1005 /* Send a code of the given tree. c and tree must not have side effects */
1006 # define SEND_CODE(c, tree) send_bits(tree[c].Code, tree[c].Len)
1008 # define SEND_CODE(c, tree) \
1010 if (verbose > 1) bb_error_msg("\ncd %3d ",(c)); \
1011 send_bits(tree[c].Code, tree[c].Len); \
1015 #define D_CODE(dist) \
1016 ((dist) < 256 ? G2.dist_code[dist] : G2.dist_code[256 + ((dist)>>7)])
1017 /* Mapping from a distance to a distance code. dist is the distance - 1 and
1018 * must not have side effects. dist_code[256] and dist_code[257] are never
1020 * The arguments must not have side effects.
1024 /* ===========================================================================
1025 * Initialize a new block.
1027 static void init_block(void)
1029 int n; /* iterates over tree elements */
1031 /* Initialize the trees. */
1032 for (n = 0; n < L_CODES; n++)
1033 G2.dyn_ltree[n].Freq = 0;
1034 for (n = 0; n < D_CODES; n++)
1035 G2.dyn_dtree[n].Freq = 0;
1036 for (n = 0; n < BL_CODES; n++)
1037 G2.bl_tree[n].Freq = 0;
1039 G2.dyn_ltree[END_BLOCK].Freq = 1;
1040 G2.opt_len = G2.static_len = 0;
1041 G2.last_lit = G2.last_dist = G2.last_flags = 0;
1047 /* ===========================================================================
1048 * Restore the heap property by moving down the tree starting at node k,
1049 * exchanging a node with the smallest of its two sons if necessary, stopping
1050 * when the heap property is re-established (each father smaller than its
1054 /* Compares to subtrees, using the tree depth as tie breaker when
1055 * the subtrees have equal frequency. This minimizes the worst case length. */
1056 #define SMALLER(tree, n, m) \
1057 (tree[n].Freq < tree[m].Freq \
1058 || (tree[n].Freq == tree[m].Freq && G2.depth[n] <= G2.depth[m]))
1060 static void pqdownheap(ct_data * tree, int k)
1063 int j = k << 1; /* left son of k */
1065 while (j <= G2.heap_len) {
1066 /* Set j to the smallest of the two sons: */
1067 if (j < G2.heap_len && SMALLER(tree, G2.heap[j + 1], G2.heap[j]))
1070 /* Exit if v is smaller than both sons */
1071 if (SMALLER(tree, v, G2.heap[j]))
1074 /* Exchange v with the smallest son */
1075 G2.heap[k] = G2.heap[j];
1078 /* And continue down the tree, setting j to the left son of k */
1085 /* ===========================================================================
1086 * Compute the optimal bit lengths for a tree and update the total bit length
1087 * for the current block.
1088 * IN assertion: the fields freq and dad are set, heap[heap_max] and
1089 * above are the tree nodes sorted by increasing frequency.
1090 * OUT assertions: the field len is set to the optimal bit length, the
1091 * array bl_count contains the frequencies for each bit length.
1092 * The length opt_len is updated; static_len is also updated if stree is
1095 static void gen_bitlen(tree_desc * desc)
1097 ct_data *tree = desc->dyn_tree;
1098 const extra_bits_t *extra = desc->extra_bits;
1099 int base = desc->extra_base;
1100 int max_code = desc->max_code;
1101 int max_length = desc->max_length;
1102 ct_data *stree = desc->static_tree;
1103 int h; /* heap index */
1104 int n, m; /* iterate over the tree elements */
1105 int bits; /* bit length */
1106 int xbits; /* extra bits */
1107 ush f; /* frequency */
1108 int overflow = 0; /* number of elements with bit length too large */
1110 for (bits = 0; bits <= MAX_BITS; bits++)
1111 G2.bl_count[bits] = 0;
1113 /* In a first pass, compute the optimal bit lengths (which may
1114 * overflow in the case of the bit length tree).
1116 tree[G2.heap[G2.heap_max]].Len = 0; /* root of the heap */
1118 for (h = G2.heap_max + 1; h < HEAP_SIZE; h++) {
1120 bits = tree[tree[n].Dad].Len + 1;
1121 if (bits > max_length) {
1125 tree[n].Len = (ush) bits;
1126 /* We overwrite tree[n].Dad which is no longer needed */
1129 continue; /* not a leaf node */
1131 G2.bl_count[bits]++;
1134 xbits = extra[n - base];
1136 G2.opt_len += (ulg) f *(bits + xbits);
1139 G2.static_len += (ulg) f * (stree[n].Len + xbits);
1144 Trace((stderr, "\nbit length overflow\n"));
1145 /* This happens for example on obj2 and pic of the Calgary corpus */
1147 /* Find the first bit length which could increase: */
1149 bits = max_length - 1;
1150 while (G2.bl_count[bits] == 0)
1152 G2.bl_count[bits]--; /* move one leaf down the tree */
1153 G2.bl_count[bits + 1] += 2; /* move one overflow item as its brother */
1154 G2.bl_count[max_length]--;
1155 /* The brother of the overflow item also moves one step up,
1156 * but this does not affect bl_count[max_length]
1159 } while (overflow > 0);
1161 /* Now recompute all bit lengths, scanning in increasing frequency.
1162 * h is still equal to HEAP_SIZE. (It is simpler to reconstruct all
1163 * lengths instead of fixing only the wrong ones. This idea is taken
1164 * from 'ar' written by Haruhiko Okumura.)
1166 for (bits = max_length; bits != 0; bits--) {
1167 n = G2.bl_count[bits];
1172 if (tree[m].Len != (unsigned) bits) {
1173 Trace((stderr, "code %d bits %d->%d\n", m, tree[m].Len, bits));
1174 G2.opt_len += ((int32_t) bits - tree[m].Len) * tree[m].Freq;
1183 /* ===========================================================================
1184 * Generate the codes for a given tree and bit counts (which need not be
1186 * IN assertion: the array bl_count contains the bit length statistics for
1187 * the given tree and the field len is set for all tree elements.
1188 * OUT assertion: the field code is set for all tree elements of non
1191 static void gen_codes(ct_data * tree, int max_code)
1193 ush next_code[MAX_BITS + 1]; /* next code value for each bit length */
1194 ush code = 0; /* running code value */
1195 int bits; /* bit index */
1196 int n; /* code index */
1198 /* The distribution counts are first used to generate the code values
1199 * without bit reversal.
1201 for (bits = 1; bits <= MAX_BITS; bits++) {
1202 next_code[bits] = code = (code + G2.bl_count[bits - 1]) << 1;
1204 /* Check that the bit counts in bl_count are consistent. The last code
1207 Assert(code + G2.bl_count[MAX_BITS] - 1 == (1 << MAX_BITS) - 1,
1208 "inconsistent bit counts");
1209 Tracev((stderr, "\ngen_codes: max_code %d ", max_code));
1211 for (n = 0; n <= max_code; n++) {
1212 int len = tree[n].Len;
1216 /* Now reverse the bits */
1217 tree[n].Code = bi_reverse(next_code[len]++, len);
1219 Tracec(tree != G2.static_ltree,
1220 (stderr, "\nn %3d %c l %2d c %4x (%x) ", n,
1221 (isgraph(n) ? n : ' '), len, tree[n].Code,
1222 next_code[len] - 1));
1227 /* ===========================================================================
1228 * Construct one Huffman tree and assigns the code bit strings and lengths.
1229 * Update the total bit length for the current block.
1230 * IN assertion: the field freq is set for all tree elements.
1231 * OUT assertions: the fields len and code are set to the optimal bit length
1232 * and corresponding code. The length opt_len is updated; static_len is
1233 * also updated if stree is not null. The field max_code is set.
1236 /* Remove the smallest element from the heap and recreate the heap with
1237 * one less element. Updates heap and heap_len. */
1240 /* Index within the heap array of least frequent node in the Huffman tree */
1242 #define PQREMOVE(tree, top) \
1244 top = G2.heap[SMALLEST]; \
1245 G2.heap[SMALLEST] = G2.heap[G2.heap_len--]; \
1246 pqdownheap(tree, SMALLEST); \
1249 static void build_tree(tree_desc * desc)
1251 ct_data *tree = desc->dyn_tree;
1252 ct_data *stree = desc->static_tree;
1253 int elems = desc->elems;
1254 int n, m; /* iterate over heap elements */
1255 int max_code = -1; /* largest code with non zero frequency */
1256 int node = elems; /* next internal node of the tree */
1258 /* Construct the initial heap, with least frequent element in
1259 * heap[SMALLEST]. The sons of heap[n] are heap[2*n] and heap[2*n+1].
1260 * heap[0] is not used.
1263 G2.heap_max = HEAP_SIZE;
1265 for (n = 0; n < elems; n++) {
1266 if (tree[n].Freq != 0) {
1267 G2.heap[++G2.heap_len] = max_code = n;
1274 /* The pkzip format requires that at least one distance code exists,
1275 * and that at least one bit should be sent even if there is only one
1276 * possible code. So to avoid special checks later on we force at least
1277 * two codes of non zero frequency.
1279 while (G2.heap_len < 2) {
1280 int new = G2.heap[++G2.heap_len] = (max_code < 2 ? ++max_code : 0);
1286 G2.static_len -= stree[new].Len;
1287 /* new is 0 or 1 so it does not have extra bits */
1289 desc->max_code = max_code;
1291 /* The elements heap[heap_len/2+1 .. heap_len] are leaves of the tree,
1292 * establish sub-heaps of increasing lengths:
1294 for (n = G2.heap_len / 2; n >= 1; n--)
1295 pqdownheap(tree, n);
1297 /* Construct the Huffman tree by repeatedly combining the least two
1301 PQREMOVE(tree, n); /* n = node of least frequency */
1302 m = G2.heap[SMALLEST]; /* m = node of next least frequency */
1304 G2.heap[--G2.heap_max] = n; /* keep the nodes sorted by frequency */
1305 G2.heap[--G2.heap_max] = m;
1307 /* Create a new node father of n and m */
1308 tree[node].Freq = tree[n].Freq + tree[m].Freq;
1309 G2.depth[node] = MAX(G2.depth[n], G2.depth[m]) + 1;
1310 tree[n].Dad = tree[m].Dad = (ush) node;
1312 if (tree == G2.bl_tree) {
1313 bb_error_msg("\nnode %d(%d), sons %d(%d) %d(%d)",
1314 node, tree[node].Freq, n, tree[n].Freq, m, tree[m].Freq);
1317 /* and insert the new node in the heap */
1318 G2.heap[SMALLEST] = node++;
1319 pqdownheap(tree, SMALLEST);
1321 } while (G2.heap_len >= 2);
1323 G2.heap[--G2.heap_max] = G2.heap[SMALLEST];
1325 /* At this point, the fields freq and dad are set. We can now
1326 * generate the bit lengths.
1328 gen_bitlen((tree_desc *) desc);
1330 /* The field len is now set, we can generate the bit codes */
1331 gen_codes((ct_data *) tree, max_code);
1335 /* ===========================================================================
1336 * Scan a literal or distance tree to determine the frequencies of the codes
1337 * in the bit length tree. Updates opt_len to take into account the repeat
1338 * counts. (The contribution of the bit length codes will be added later
1339 * during the construction of bl_tree.)
1341 static void scan_tree(ct_data * tree, int max_code)
1343 int n; /* iterates over all tree elements */
1344 int prevlen = -1; /* last emitted length */
1345 int curlen; /* length of current code */
1346 int nextlen = tree[0].Len; /* length of next code */
1347 int count = 0; /* repeat count of the current code */
1348 int max_count = 7; /* max repeat count */
1349 int min_count = 4; /* min repeat count */
1355 tree[max_code + 1].Len = 0xffff; /* guard */
1357 for (n = 0; n <= max_code; n++) {
1359 nextlen = tree[n + 1].Len;
1360 if (++count < max_count && curlen == nextlen)
1363 if (count < min_count) {
1364 G2.bl_tree[curlen].Freq += count;
1365 } else if (curlen != 0) {
1366 if (curlen != prevlen)
1367 G2.bl_tree[curlen].Freq++;
1368 G2.bl_tree[REP_3_6].Freq++;
1369 } else if (count <= 10) {
1370 G2.bl_tree[REPZ_3_10].Freq++;
1372 G2.bl_tree[REPZ_11_138].Freq++;
1382 } else if (curlen == nextlen) {
1390 /* ===========================================================================
1391 * Send a literal or distance tree in compressed form, using the codes in
1394 static void send_tree(ct_data * tree, int max_code)
1396 int n; /* iterates over all tree elements */
1397 int prevlen = -1; /* last emitted length */
1398 int curlen; /* length of current code */
1399 int nextlen = tree[0].Len; /* length of next code */
1400 int count = 0; /* repeat count of the current code */
1401 int max_count = 7; /* max repeat count */
1402 int min_count = 4; /* min repeat count */
1404 /* tree[max_code+1].Len = -1; *//* guard already set */
1406 max_count = 138, min_count = 3;
1408 for (n = 0; n <= max_code; n++) {
1410 nextlen = tree[n + 1].Len;
1411 if (++count < max_count && curlen == nextlen) {
1413 } else if (count < min_count) {
1415 SEND_CODE(curlen, G2.bl_tree);
1417 } else if (curlen != 0) {
1418 if (curlen != prevlen) {
1419 SEND_CODE(curlen, G2.bl_tree);
1422 Assert(count >= 3 && count <= 6, " 3_6?");
1423 SEND_CODE(REP_3_6, G2.bl_tree);
1424 send_bits(count - 3, 2);
1425 } else if (count <= 10) {
1426 SEND_CODE(REPZ_3_10, G2.bl_tree);
1427 send_bits(count - 3, 3);
1429 SEND_CODE(REPZ_11_138, G2.bl_tree);
1430 send_bits(count - 11, 7);
1437 } else if (curlen == nextlen) {
1448 /* ===========================================================================
1449 * Construct the Huffman tree for the bit lengths and return the index in
1450 * bl_order of the last bit length code to send.
1452 static int build_bl_tree(void)
1454 int max_blindex; /* index of last bit length code of non zero freq */
1456 /* Determine the bit length frequencies for literal and distance trees */
1457 scan_tree(G2.dyn_ltree, G2.l_desc.max_code);
1458 scan_tree(G2.dyn_dtree, G2.d_desc.max_code);
1460 /* Build the bit length tree: */
1461 build_tree(&G2.bl_desc);
1462 /* opt_len now includes the length of the tree representations, except
1463 * the lengths of the bit lengths codes and the 5+5+4 bits for the counts.
1466 /* Determine the number of bit length codes to send. The pkzip format
1467 * requires that at least 4 bit length codes be sent. (appnote.txt says
1468 * 3 but the actual value used is 4.)
1470 for (max_blindex = BL_CODES - 1; max_blindex >= 3; max_blindex--) {
1471 if (G2.bl_tree[bl_order[max_blindex]].Len != 0)
1474 /* Update opt_len to include the bit length tree and counts */
1475 G2.opt_len += 3 * (max_blindex + 1) + 5 + 5 + 4;
1476 Tracev((stderr, "\ndyn trees: dyn %ld, stat %ld", G2.opt_len, G2.static_len));
1482 /* ===========================================================================
1483 * Send the header for a block using dynamic Huffman trees: the counts, the
1484 * lengths of the bit length codes, the literal tree and the distance tree.
1485 * IN assertion: lcodes >= 257, dcodes >= 1, blcodes >= 4.
1487 static void send_all_trees(int lcodes, int dcodes, int blcodes)
1489 int rank; /* index in bl_order */
1491 Assert(lcodes >= 257 && dcodes >= 1 && blcodes >= 4, "not enough codes");
1492 Assert(lcodes <= L_CODES && dcodes <= D_CODES
1493 && blcodes <= BL_CODES, "too many codes");
1494 Tracev((stderr, "\nbl counts: "));
1495 send_bits(lcodes - 257, 5); /* not +255 as stated in appnote.txt */
1496 send_bits(dcodes - 1, 5);
1497 send_bits(blcodes - 4, 4); /* not -3 as stated in appnote.txt */
1498 for (rank = 0; rank < blcodes; rank++) {
1499 Tracev((stderr, "\nbl code %2d ", bl_order[rank]));
1500 send_bits(G2.bl_tree[bl_order[rank]].Len, 3);
1502 Tracev((stderr, "\nbl tree: sent %ld", G1.bits_sent));
1504 send_tree((ct_data *) G2.dyn_ltree, lcodes - 1); /* send the literal tree */
1505 Tracev((stderr, "\nlit tree: sent %ld", G1.bits_sent));
1507 send_tree((ct_data *) G2.dyn_dtree, dcodes - 1); /* send the distance tree */
1508 Tracev((stderr, "\ndist tree: sent %ld", G1.bits_sent));
1512 /////* ===========================================================================
1513 //// * Set the file type to ASCII or BINARY, using a crude approximation:
1514 //// * binary if more than 20% of the bytes are <= 6 or >= 128, ascii otherwise.
1515 //// * IN assertion: the fields freq of dyn_ltree are set and the total of all
1516 //// * frequencies does not exceed 64K (to fit in an int on 16 bit machines).
1518 ////static void set_file_type(void)
1521 //// unsigned ascii_freq = 0;
1522 //// unsigned bin_freq = 0;
1525 //// bin_freq += G2.dyn_ltree[n++].Freq;
1526 //// while (n < 128)
1527 //// ascii_freq += G2.dyn_ltree[n++].Freq;
1528 //// while (n < LITERALS)
1529 //// bin_freq += G2.dyn_ltree[n++].Freq;
1530 //// *G2.file_type = (bin_freq > (ascii_freq >> 2)) ? BINARY : ASCII;
1531 //// if (*G2.file_type == BINARY && translate_eol) {
1532 //// bb_error_msg("-l used on binary file");
1537 /* ===========================================================================
1538 * Save the match info and tally the frequency counts. Return true if
1539 * the current block must be flushed.
1541 static int ct_tally(int dist, int lc)
1543 G1.l_buf[G2.last_lit++] = lc;
1545 /* lc is the unmatched char */
1546 G2.dyn_ltree[lc].Freq++;
1548 /* Here, lc is the match length - MIN_MATCH */
1549 dist--; /* dist = match distance - 1 */
1550 Assert((ush) dist < (ush) MAX_DIST
1551 && (ush) lc <= (ush) (MAX_MATCH - MIN_MATCH)
1552 && (ush) D_CODE(dist) < (ush) D_CODES, "ct_tally: bad match"
1555 G2.dyn_ltree[G2.length_code[lc] + LITERALS + 1].Freq++;
1556 G2.dyn_dtree[D_CODE(dist)].Freq++;
1558 G1.d_buf[G2.last_dist++] = dist;
1559 G2.flags |= G2.flag_bit;
1563 /* Output the flags if they fill a byte: */
1564 if ((G2.last_lit & 7) == 0) {
1565 G2.flag_buf[G2.last_flags++] = G2.flags;
1569 /* Try to guess if it is profitable to stop the current block here */
1570 if ((G2.last_lit & 0xfff) == 0) {
1571 /* Compute an upper bound for the compressed length */
1572 ulg out_length = G2.last_lit * 8L;
1573 ulg in_length = (ulg) G1.strstart - G1.block_start;
1576 for (dcode = 0; dcode < D_CODES; dcode++) {
1577 out_length += G2.dyn_dtree[dcode].Freq * (5L + extra_dbits[dcode]);
1581 "\nlast_lit %u, last_dist %u, in %ld, out ~%ld(%ld%%) ",
1582 G2.last_lit, G2.last_dist, in_length, out_length,
1583 100L - out_length * 100L / in_length));
1584 if (G2.last_dist < G2.last_lit / 2 && out_length < in_length / 2)
1587 return (G2.last_lit == LIT_BUFSIZE - 1 || G2.last_dist == DIST_BUFSIZE);
1588 /* We avoid equality with LIT_BUFSIZE because of wraparound at 64K
1589 * on 16 bit machines and because stored blocks are restricted to
1594 /* ===========================================================================
1595 * Send the block data compressed using the given Huffman trees
1597 static void compress_block(ct_data * ltree, ct_data * dtree)
1599 unsigned dist; /* distance of matched string */
1600 int lc; /* match length or unmatched char (if dist == 0) */
1601 unsigned lx = 0; /* running index in l_buf */
1602 unsigned dx = 0; /* running index in d_buf */
1603 unsigned fx = 0; /* running index in flag_buf */
1604 uch flag = 0; /* current flags */
1605 unsigned code; /* the code to send */
1606 int extra; /* number of extra bits to send */
1608 if (G2.last_lit != 0) do {
1610 flag = G2.flag_buf[fx++];
1611 lc = G1.l_buf[lx++];
1612 if ((flag & 1) == 0) {
1613 SEND_CODE(lc, ltree); /* send a literal byte */
1614 Tracecv(isgraph(lc), (stderr, " '%c' ", lc));
1616 /* Here, lc is the match length - MIN_MATCH */
1617 code = G2.length_code[lc];
1618 SEND_CODE(code + LITERALS + 1, ltree); /* send the length code */
1619 extra = extra_lbits[code];
1621 lc -= G2.base_length[code];
1622 send_bits(lc, extra); /* send the extra length bits */
1624 dist = G1.d_buf[dx++];
1625 /* Here, dist is the match distance - 1 */
1626 code = D_CODE(dist);
1627 Assert(code < D_CODES, "bad d_code");
1629 SEND_CODE(code, dtree); /* send the distance code */
1630 extra = extra_dbits[code];
1632 dist -= G2.base_dist[code];
1633 send_bits(dist, extra); /* send the extra distance bits */
1635 } /* literal or match pair ? */
1637 } while (lx < G2.last_lit);
1639 SEND_CODE(END_BLOCK, ltree);
1643 /* ===========================================================================
1644 * Determine the best encoding for the current block: dynamic trees, static
1645 * trees or store, and output the encoded block to the zip file. This function
1646 * returns the total compressed length for the file so far.
1648 static ulg flush_block(char *buf, ulg stored_len, int eof)
1650 ulg opt_lenb, static_lenb; /* opt_len and static_len in bytes */
1651 int max_blindex; /* index of last bit length code of non zero freq */
1653 G2.flag_buf[G2.last_flags] = G2.flags; /* Save the flags for the last 8 items */
1655 //// /* Check if the file is ascii or binary */
1656 //// if (*G2.file_type == (ush) UNKNOWN)
1657 //// set_file_type();
1659 /* Construct the literal and distance trees */
1660 build_tree(&G2.l_desc);
1661 Tracev((stderr, "\nlit data: dyn %ld, stat %ld", G2.opt_len, G2.static_len));
1663 build_tree(&G2.d_desc);
1664 Tracev((stderr, "\ndist data: dyn %ld, stat %ld", G2.opt_len, G2.static_len));
1665 /* At this point, opt_len and static_len are the total bit lengths of
1666 * the compressed block data, excluding the tree representations.
1669 /* Build the bit length tree for the above two trees, and get the index
1670 * in bl_order of the last bit length code to send.
1672 max_blindex = build_bl_tree();
1674 /* Determine the best encoding. Compute first the block length in bytes */
1675 opt_lenb = (G2.opt_len + 3 + 7) >> 3;
1676 static_lenb = (G2.static_len + 3 + 7) >> 3;
1679 "\nopt %lu(%lu) stat %lu(%lu) stored %lu lit %u dist %u ",
1680 opt_lenb, G2.opt_len, static_lenb, G2.static_len, stored_len,
1681 G2.last_lit, G2.last_dist));
1683 if (static_lenb <= opt_lenb)
1684 opt_lenb = static_lenb;
1686 /* If compression failed and this is the first and last block,
1687 * and if the zip file can be seeked (to rewrite the local header),
1688 * the whole file is transformed into a stored file:
1690 if (stored_len <= opt_lenb && eof && G2.compressed_len == 0L && seekable()) {
1691 /* Since LIT_BUFSIZE <= 2*WSIZE, the input data must be there: */
1693 bb_error_msg("block vanished");
1695 copy_block(buf, (unsigned) stored_len, 0); /* without header */
1696 G2.compressed_len = stored_len << 3;
1697 //// *file_method = STORED;
1699 } else if (stored_len + 4 <= opt_lenb && buf != NULL) {
1700 /* 4: two words for the lengths */
1701 /* The test buf != NULL is only necessary if LIT_BUFSIZE > WSIZE.
1702 * Otherwise we can't have processed more than WSIZE input bytes since
1703 * the last block flush, because compression would have been
1704 * successful. If LIT_BUFSIZE <= WSIZE, it is never too late to
1705 * transform a block into a stored block.
1707 send_bits((STORED_BLOCK << 1) + eof, 3); /* send block type */
1708 G2.compressed_len = (G2.compressed_len + 3 + 7) & ~7L;
1709 G2.compressed_len += (stored_len + 4) << 3;
1711 copy_block(buf, (unsigned) stored_len, 1); /* with header */
1713 } else if (static_lenb == opt_lenb) {
1714 send_bits((STATIC_TREES << 1) + eof, 3);
1715 compress_block((ct_data *) G2.static_ltree, (ct_data *) G2.static_dtree);
1716 G2.compressed_len += 3 + G2.static_len;
1718 send_bits((DYN_TREES << 1) + eof, 3);
1719 send_all_trees(G2.l_desc.max_code + 1, G2.d_desc.max_code + 1,
1721 compress_block((ct_data *) G2.dyn_ltree, (ct_data *) G2.dyn_dtree);
1722 G2.compressed_len += 3 + G2.opt_len;
1724 Assert(G2.compressed_len == G1.bits_sent, "bad compressed size");
1729 G2.compressed_len += 7; /* align on byte boundary */
1731 Tracev((stderr, "\ncomprlen %lu(%lu) ", G2.compressed_len >> 3,
1732 G2.compressed_len - 7 * eof));
1734 return G2.compressed_len >> 3;
1738 /* ===========================================================================
1739 * Update a hash value with the given input byte
1740 * IN assertion: all calls to to UPDATE_HASH are made with consecutive
1741 * input characters, so that a running hash key can be computed from the
1742 * previous key instead of complete recalculation each time.
1744 #define UPDATE_HASH(h, c) (h = (((h)<<H_SHIFT) ^ (c)) & HASH_MASK)
1747 /* ===========================================================================
1748 * Same as above, but achieves better compression. We use a lazy
1749 * evaluation for matches: a match is finally adopted only if there is
1750 * no better match at the next window position.
1752 * Processes a new input file and return its compressed length. Sets
1753 * the compressed length, crc, deflate flags and internal file
1757 /* Flush the current block, with given end-of-file flag.
1758 * IN assertion: strstart is set to the end of the current match. */
1759 #define FLUSH_BLOCK(eof) \
1761 G1.block_start >= 0L \
1762 ? (char*)&G1.window[(unsigned)G1.block_start] \
1764 (ulg)G1.strstart - G1.block_start, \
1768 /* Insert string s in the dictionary and set match_head to the previous head
1769 * of the hash chain (the most recent string with same hash key). Return
1770 * the previous length of the hash chain.
1771 * IN assertion: all calls to to INSERT_STRING are made with consecutive
1772 * input characters and the first MIN_MATCH bytes of s are valid
1773 * (except for the last MIN_MATCH-1 bytes of the input file). */
1774 #define INSERT_STRING(s, match_head) \
1776 UPDATE_HASH(G1.ins_h, G1.window[(s) + MIN_MATCH-1]); \
1777 G1.prev[(s) & WMASK] = match_head = head[G1.ins_h]; \
1778 head[G1.ins_h] = (s); \
1781 static ulg deflate(void)
1783 IPos hash_head; /* head of hash chain */
1784 IPos prev_match; /* previous match */
1785 int flush; /* set if current block must be flushed */
1786 int match_available = 0; /* set if previous match exists */
1787 unsigned match_length = MIN_MATCH - 1; /* length of best match */
1789 /* Process the input block. */
1790 while (G1.lookahead != 0) {
1791 /* Insert the string window[strstart .. strstart+2] in the
1792 * dictionary, and set hash_head to the head of the hash chain:
1794 INSERT_STRING(G1.strstart, hash_head);
1796 /* Find the longest match, discarding those <= prev_length.
1798 G1.prev_length = match_length;
1799 prev_match = G1.match_start;
1800 match_length = MIN_MATCH - 1;
1802 if (hash_head != 0 && G1.prev_length < max_lazy_match
1803 && G1.strstart - hash_head <= MAX_DIST
1805 /* To simplify the code, we prevent matches with the string
1806 * of window index 0 (in particular we have to avoid a match
1807 * of the string with itself at the start of the input file).
1809 match_length = longest_match(hash_head);
1810 /* longest_match() sets match_start */
1811 if (match_length > G1.lookahead)
1812 match_length = G1.lookahead;
1814 /* Ignore a length 3 match if it is too distant: */
1815 if (match_length == MIN_MATCH && G1.strstart - G1.match_start > TOO_FAR) {
1816 /* If prev_match is also MIN_MATCH, G1.match_start is garbage
1817 * but we will ignore the current match anyway.
1822 /* If there was a match at the previous step and the current
1823 * match is not better, output the previous match:
1825 if (G1.prev_length >= MIN_MATCH && match_length <= G1.prev_length) {
1826 check_match(G1.strstart - 1, prev_match, G1.prev_length);
1827 flush = ct_tally(G1.strstart - 1 - prev_match, G1.prev_length - MIN_MATCH);
1829 /* Insert in hash table all strings up to the end of the match.
1830 * strstart-1 and strstart are already inserted.
1832 G1.lookahead -= G1.prev_length - 1;
1833 G1.prev_length -= 2;
1836 INSERT_STRING(G1.strstart, hash_head);
1837 /* strstart never exceeds WSIZE-MAX_MATCH, so there are
1838 * always MIN_MATCH bytes ahead. If lookahead < MIN_MATCH
1839 * these bytes are garbage, but it does not matter since the
1840 * next lookahead bytes will always be emitted as literals.
1842 } while (--G1.prev_length != 0);
1843 match_available = 0;
1844 match_length = MIN_MATCH - 1;
1848 G1.block_start = G1.strstart;
1850 } else if (match_available) {
1851 /* If there was no match at the previous position, output a
1852 * single literal. If there was a match but the current match
1853 * is longer, truncate the previous match to a single literal.
1855 Tracevv((stderr, "%c", G1.window[G1.strstart - 1]));
1856 if (ct_tally(0, G1.window[G1.strstart - 1])) {
1858 G1.block_start = G1.strstart;
1863 /* There is no previous match to compare with, wait for
1864 * the next step to decide.
1866 match_available = 1;
1870 Assert(G1.strstart <= G1.isize && lookahead <= G1.isize, "a bit too far");
1872 /* Make sure that we always have enough lookahead, except
1873 * at the end of the input file. We need MAX_MATCH bytes
1874 * for the next match, plus MIN_MATCH bytes to insert the
1875 * string following the next match.
1877 while (G1.lookahead < MIN_LOOKAHEAD && !G1.eofile)
1880 if (match_available)
1881 ct_tally(0, G1.window[G1.strstart - 1]);
1883 return FLUSH_BLOCK(1); /* eof */
1887 /* ===========================================================================
1888 * Initialize the bit string routines.
1890 static void bi_init(void)
1900 /* ===========================================================================
1901 * Initialize the "longest match" routines for a new file
1903 static void lm_init(ush * flagsp)
1907 /* Initialize the hash table. */
1908 memset(head, 0, HASH_SIZE * sizeof(*head));
1909 /* prev will be initialized on the fly */
1911 /* speed options for the general purpose bit flag */
1912 *flagsp |= 2; /* FAST 4, SLOW 2 */
1913 /* ??? reduce max_chain_length for binary files */
1916 G1.block_start = 0L;
1918 G1.lookahead = file_read(G1.window,
1919 sizeof(int) <= 2 ? (unsigned) WSIZE : 2 * WSIZE);
1921 if (G1.lookahead == 0 || G1.lookahead == (unsigned) -1) {
1927 /* Make sure that we always have enough lookahead. This is important
1928 * if input comes from a device such as a tty.
1930 while (G1.lookahead < MIN_LOOKAHEAD && !G1.eofile)
1934 for (j = 0; j < MIN_MATCH - 1; j++)
1935 UPDATE_HASH(G1.ins_h, G1.window[j]);
1936 /* If lookahead < MIN_MATCH, ins_h is garbage, but this is
1937 * not important since only literal bytes will be emitted.
1942 /* ===========================================================================
1943 * Allocate the match buffer, initialize the various tables and save the
1944 * location of the internal file attribute (ascii/binary) and method
1946 * One callsite in zip()
1948 static void ct_init(void) ////ush * attr, int *methodp)
1950 int n; /* iterates over tree elements */
1951 int length; /* length value */
1952 int code; /* code value */
1953 int dist; /* distance index */
1955 //// file_type = attr;
1956 //// file_method = methodp;
1957 G2.compressed_len = 0L;
1960 if (G2.static_dtree[0].Len != 0)
1961 return; /* ct_init already called */
1964 /* Initialize the mapping length (0..255) -> length code (0..28) */
1966 for (code = 0; code < LENGTH_CODES - 1; code++) {
1967 G2.base_length[code] = length;
1968 for (n = 0; n < (1 << extra_lbits[code]); n++) {
1969 G2.length_code[length++] = code;
1972 Assert(length == 256, "ct_init: length != 256");
1973 /* Note that the length 255 (match length 258) can be represented
1974 * in two different ways: code 284 + 5 bits or code 285, so we
1975 * overwrite length_code[255] to use the best encoding:
1977 G2.length_code[length - 1] = code;
1979 /* Initialize the mapping dist (0..32K) -> dist code (0..29) */
1981 for (code = 0; code < 16; code++) {
1982 G2.base_dist[code] = dist;
1983 for (n = 0; n < (1 << extra_dbits[code]); n++) {
1984 G2.dist_code[dist++] = code;
1987 Assert(dist == 256, "ct_init: dist != 256");
1988 dist >>= 7; /* from now on, all distances are divided by 128 */
1989 for (; code < D_CODES; code++) {
1990 G2.base_dist[code] = dist << 7;
1991 for (n = 0; n < (1 << (extra_dbits[code] - 7)); n++) {
1992 G2.dist_code[256 + dist++] = code;
1995 Assert(dist == 256, "ct_init: 256+dist != 512");
1997 /* Construct the codes of the static literal tree */
1998 /* already zeroed - it's in bss
1999 for (n = 0; n <= MAX_BITS; n++)
2000 G2.bl_count[n] = 0; */
2004 G2.static_ltree[n++].Len = 8;
2008 G2.static_ltree[n++].Len = 9;
2012 G2.static_ltree[n++].Len = 7;
2016 G2.static_ltree[n++].Len = 8;
2019 /* Codes 286 and 287 do not exist, but we must include them in the
2020 * tree construction to get a canonical Huffman tree (longest code
2023 gen_codes((ct_data *) G2.static_ltree, L_CODES + 1);
2025 /* The static distance tree is trivial: */
2026 for (n = 0; n < D_CODES; n++) {
2027 G2.static_dtree[n].Len = 5;
2028 G2.static_dtree[n].Code = bi_reverse(n, 5);
2031 /* Initialize the first block of the first file: */
2036 /* ===========================================================================
2037 * Deflate in to out.
2038 * IN assertions: the input and output buffers are cleared.
2039 * The variables time_stamp and save_orig_name are initialized.
2042 /* put_header_byte is used for the compressed output
2043 * - for the initial 4 bytes that can't overflow the buffer. */
2044 #define put_header_byte(c) G1.outbuf[G1.outcnt++] = (c)
2046 static void zip(int in, int out)
2048 uch my_flags = 0; /* general purpose bit flags */
2049 //// ush attr = 0; /* ascii/binary flag */
2050 ush deflate_flags = 0; /* pkzip -es, -en or -ex equivalent */
2051 //// int method = DEFLATED; /* compression method */
2057 /* Write the header to the gzip file. See algorithm.doc for the format */
2059 put_header_byte(0x1f); /* magic header for gzip files, 1F 8B */
2060 put_header_byte(0x8b);
2061 ////put_header_byte(DEFLATED); /* compression method */
2062 put_header_byte(8); /* compression method */
2063 put_header_byte(my_flags); /* general flags */
2064 put_32bit(G1.time_stamp);
2066 /* Write deflated file to zip file */
2070 ct_init(); //// &attr, &method);
2071 lm_init(&deflate_flags);
2073 put_8bit(deflate_flags); /* extra flags */
2074 put_8bit(3); /* OS identifier = 3 (Unix) */
2078 /* Write the crc and uncompressed size */
2080 put_32bit(G1.isize);
2086 /* ======================================================================== */
2087 static void abort_gzip(int ATTRIBUTE_UNUSED ignored)
2092 int gzip_main(int argc, char **argv);
2093 int gzip_main(int argc, char **argv)
2104 struct stat statBuf;
2106 opt = getopt32(argc, argv, "cf123456789qv" USE_GUNZIP("d"));
2107 //if (opt & 0x1) // -c
2108 //if (opt & 0x2) // -f
2109 /* Ignore 1-9 (compression level) options */
2110 //if (opt & 0x4) // -1
2111 //if (opt & 0x8) // -2
2112 //if (opt & 0x10) // -3
2113 //if (opt & 0x20) // -4
2114 //if (opt & 0x40) // -5
2115 //if (opt & 0x80) // -6
2116 //if (opt & 0x100) // -7
2117 //if (opt & 0x200) // -8
2118 //if (opt & 0x400) // -9
2119 //if (opt & 0x800) // -q
2120 //if (opt & 0x1000) // -v
2121 #if ENABLE_GUNZIP /* gunzip_main may not be visible... */
2122 if (opt & 0x2000) { // -d
2123 /* FIXME: getopt32 should not depend on optind */
2125 return gunzip_main(argc, argv);
2130 if (signal(SIGINT, SIG_IGN) != SIG_IGN) {
2131 signal(SIGINT, abort_gzip);
2134 if (signal(SIGTERM, SIG_IGN) != SIG_IGN) {
2135 signal(SIGTERM, abort_gzip);
2139 if (signal(SIGHUP, SIG_IGN) != SIG_IGN) {
2140 signal(SIGHUP, abort_gzip);
2144 G2ptr = xzalloc(sizeof(*G2ptr));
2145 G2.l_desc = (tree_desc) {
2146 G2.dyn_ltree, G2.static_ltree, extra_lbits,
2147 LITERALS + 1, L_CODES, MAX_BITS, 0
2149 G2.d_desc = (tree_desc) {
2150 G2.dyn_dtree, G2.static_dtree, extra_dbits,
2151 0, D_CODES, MAX_BITS, 0
2153 G2.bl_desc = (tree_desc) {
2154 G2.bl_tree, NULL, extra_blbits,
2155 0, BL_CODES, MAX_BL_BITS, 0
2158 /* Allocate all global buffers (for DYN_ALLOC option) */
2159 ALLOC(uch, G1.l_buf, INBUFSIZ);
2160 ALLOC(uch, G1.outbuf, OUTBUFSIZ);
2161 ALLOC(ush, G1.d_buf, DIST_BUFSIZE);
2162 ALLOC(uch, G1.window, 2L * WSIZE);
2163 ALLOC(ush, G1.prev, 1L << BITS);
2165 /* Initialise the CRC32 table */
2166 G1.crc_32_tab = crc32_filltable(0);
2170 if (optind == argc) {
2172 zip(STDIN_FILENO, STDOUT_FILENO);
2173 return 0; //## G1.exit_code;
2176 for (i = optind; i < argc; i++) {
2180 if (LONE_DASH(argv[i])) {
2182 inFileNum = STDIN_FILENO;
2183 outFileNum = STDOUT_FILENO;
2185 inFileNum = xopen(argv[i], O_RDONLY);
2186 if (fstat(inFileNum, &statBuf) < 0)
2187 bb_perror_msg_and_die("%s", argv[i]);
2188 G1.time_stamp = statBuf.st_ctime;
2190 if (!(opt & OPT_tostdout)) {
2191 path = xasprintf("%s.gz", argv[i]);
2193 /* Open output file */
2194 #if defined(__GLIBC__) && __GLIBC__ >= 2 && __GLIBC_MINOR__ >= 1 && defined(O_NOFOLLOW)
2195 outFileNum = open(path, O_RDWR | O_CREAT | O_EXCL | O_NOFOLLOW);
2197 outFileNum = open(path, O_RDWR | O_CREAT | O_EXCL);
2199 if (outFileNum < 0) {
2200 bb_perror_msg("%s", path);
2205 /* Set permissions on the file */
2206 fchmod(outFileNum, statBuf.st_mode);
2208 outFileNum = STDOUT_FILENO;
2211 if (path == NULL && isatty(outFileNum) && !(opt & OPT_force)) {
2212 bb_error_msg("compressed data not written "
2213 "to a terminal. Use -f to force compression.");
2218 zip(inFileNum, outFileNum);
2226 /* Delete the original file */
2227 // Pity we don't propagate zip failures to this place...
2229 delFileName = argv[i];
2231 // delFileName = path;
2232 if (unlink(delFileName) < 0)
2233 bb_perror_msg("%s", delFileName);
2239 return 0; //##G1.exit_code;