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hush/archival/gzip.c
Denys Vlasenko f560422fa0 Big cleanup in config help and description 
Redundant help texts (one which only repeats the description)
are deleted.

Descriptions and help texts are trimmed.

Some config options are moved, even across menus.

No config option _names_ are changed.

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2017-01-10 14:58:54 +01:00

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/* vi: set sw=4 ts=4: */
/*
* Gzip implementation for busybox
*
* Based on GNU gzip Copyright (C) 1992-1993 Jean-loup Gailly.
*
* Originally adjusted for busybox by Charles P. Wright <cpw@unix.asb.com>
* "this is a stripped down version of gzip I put into busybox, it does
* only standard in to standard out with -9 compression. It also requires
* the zcat module for some important functions."
*
* Adjusted further by Erik Andersen <andersen@codepoet.org> to support
* files as well as stdin/stdout, and to generally behave itself wrt
* command line handling.
*
* Licensed under GPLv2 or later, see file LICENSE in this source tree.
*/
/* big objects in bss:
* 00000020 b bl_count
* 00000074 b base_length
* 00000078 b base_dist
* 00000078 b static_dtree
* 0000009c b bl_tree
* 000000f4 b dyn_dtree
* 00000100 b length_code
* 00000200 b dist_code
* 0000023d b depth
* 00000400 b flag_buf
* 0000047a b heap
* 00000480 b static_ltree
* 000008f4 b dyn_ltree
*/
/* TODO: full support for -v for DESKTOP
* "/usr/bin/gzip -v a bogus aa" should say:
a: 85.1% -- replaced with a.gz
gzip: bogus: No such file or directory
aa: 85.1% -- replaced with aa.gz
*/
//config:config GZIP
//config: bool "gzip"
//config: default y
//config: help
//config: gzip is used to compress files.
//config: It's probably the most widely used UNIX compression program.
//config:
//config:config FEATURE_GZIP_LONG_OPTIONS
//config: bool "Enable long options"
//config: default y
//config: depends on GZIP && LONG_OPTS
//config:
//config:config GZIP_FAST
//config: int "Trade memory for speed (0:small,slow - 2:fast,big)"
//config: default 0
//config: range 0 2
//config: depends on GZIP
//config: help
//config: Enable big memory options for gzip.
//config: 0: small buffers, small hash-tables
//config: 1: larger buffers, larger hash-tables
//config: 2: larger buffers, largest hash-tables
//config: Larger models may give slightly better compression
//config:
//config:config FEATURE_GZIP_LEVELS
//config: bool "Enable compression levels"
//config: default n
//config: depends on GZIP
//config: help
//config: Enable support for compression levels 4-9. The default level
//config: is 6. If levels 1-3 are specified, 4 is used.
//config: If this option is not selected, -N options are ignored and -9
//config: is used.
//config:
//config:config FEATURE_GZIP_DECOMPRESS
//config: bool "Enable decompression"
//config: default y
//config: depends on GZIP || GUNZIP || ZCAT
//config: help
//config: Enable -d (--decompress) and -t (--test) options for gzip.
//config: This will be automatically selected if gunzip or zcat is
//config: enabled.
//applet:IF_GZIP(APPLET(gzip, BB_DIR_BIN, BB_SUID_DROP))
//kbuild:lib-$(CONFIG_GZIP) += gzip.o
//usage:#define gzip_trivial_usage
//usage: "[-cf" IF_FEATURE_GZIP_DECOMPRESS("dt") IF_FEATURE_GZIP_LEVELS("123456789") "] [FILE]..."
//usage:#define gzip_full_usage "\n\n"
//usage: "Compress FILEs (or stdin)\n"
//usage: IF_FEATURE_GZIP_LEVELS(
//usage: "\n -1..9 Compression level"
//usage: )
//usage: IF_FEATURE_GZIP_DECOMPRESS(
//usage: "\n -d Decompress"
//usage: "\n -t Test file integrity"
//usage: )
//usage: "\n -c Write to stdout"
//usage: "\n -f Force"
//usage:
//usage:#define gzip_example_usage
//usage: "$ ls -la /tmp/busybox*\n"
//usage: "-rw-rw-r-- 1 andersen andersen 1761280 Apr 14 17:47 /tmp/busybox.tar\n"
//usage: "$ gzip /tmp/busybox.tar\n"
//usage: "$ ls -la /tmp/busybox*\n"
//usage: "-rw-rw-r-- 1 andersen andersen 554058 Apr 14 17:49 /tmp/busybox.tar.gz\n"
#include "libbb.h"
#include "bb_archive.h"
/* ===========================================================================
*/
//#define DEBUG 1
/* Diagnostic functions */
#ifdef DEBUG
# define Assert(cond,msg) { if (!(cond)) bb_error_msg(msg); }
# define Trace(x) fprintf x
# define Tracev(x) {if (verbose) fprintf x; }
# define Tracevv(x) {if (verbose > 1) fprintf x; }
# define Tracec(c,x) {if (verbose && (c)) fprintf x; }
# define Tracecv(c,x) {if (verbose > 1 && (c)) fprintf x; }
#else
# define Assert(cond,msg)
# define Trace(x)
# define Tracev(x)
# define Tracevv(x)
# define Tracec(c,x)
# define Tracecv(c,x)
#endif
/* ===========================================================================
*/
#if CONFIG_GZIP_FAST == 0
# define SMALL_MEM
#elif CONFIG_GZIP_FAST == 1
# define MEDIUM_MEM
#elif CONFIG_GZIP_FAST == 2
# define BIG_MEM
#else
# error "Invalid CONFIG_GZIP_FAST value"
#endif
#ifndef INBUFSIZ
# ifdef SMALL_MEM
# define INBUFSIZ 0x2000 /* input buffer size */
# else
# define INBUFSIZ 0x8000 /* input buffer size */
# endif
#endif
#ifndef OUTBUFSIZ
# ifdef SMALL_MEM
# define OUTBUFSIZ 8192 /* output buffer size */
# else
# define OUTBUFSIZ 16384 /* output buffer size */
# endif
#endif
#ifndef DIST_BUFSIZE
# ifdef SMALL_MEM
# define DIST_BUFSIZE 0x2000 /* buffer for distances, see trees.c */
# else
# define DIST_BUFSIZE 0x8000 /* buffer for distances, see trees.c */
# endif
#endif
/* gzip flag byte */
#define ASCII_FLAG 0x01 /* bit 0 set: file probably ascii text */
#define CONTINUATION 0x02 /* bit 1 set: continuation of multi-part gzip file */
#define EXTRA_FIELD 0x04 /* bit 2 set: extra field present */
#define ORIG_NAME 0x08 /* bit 3 set: original file name present */
#define COMMENT 0x10 /* bit 4 set: file comment present */
#define RESERVED 0xC0 /* bit 6,7: reserved */
/* internal file attribute */
#define UNKNOWN 0xffff
#define BINARY 0
#define ASCII 1
#ifndef WSIZE
# define WSIZE 0x8000 /* window size--must be a power of two, and */
#endif /* at least 32K for zip's deflate method */
#define MIN_MATCH 3
#define MAX_MATCH 258
/* The minimum and maximum match lengths */
#define MIN_LOOKAHEAD (MAX_MATCH+MIN_MATCH+1)
/* Minimum amount of lookahead, except at the end of the input file.
* See deflate.c for comments about the MIN_MATCH+1.
*/
#define MAX_DIST (WSIZE-MIN_LOOKAHEAD)
/* In order to simplify the code, particularly on 16 bit machines, match
* distances are limited to MAX_DIST instead of WSIZE.
*/
#ifndef MAX_PATH_LEN
# define MAX_PATH_LEN 1024 /* max pathname length */
#endif
#define seekable() 0 /* force sequential output */
#define translate_eol 0 /* no option -a yet */
#ifndef BITS
# define BITS 16
#endif
#define INIT_BITS 9 /* Initial number of bits per code */
#define BIT_MASK 0x1f /* Mask for 'number of compression bits' */
/* Mask 0x20 is reserved to mean a fourth header byte, and 0x40 is free.
* It's a pity that old uncompress does not check bit 0x20. That makes
* extension of the format actually undesirable because old compress
* would just crash on the new format instead of giving a meaningful
* error message. It does check the number of bits, but it's more
* helpful to say "unsupported format, get a new version" than
* "can only handle 16 bits".
*/
#ifdef MAX_EXT_CHARS
# define MAX_SUFFIX MAX_EXT_CHARS
#else
# define MAX_SUFFIX 30
#endif
/* ===========================================================================
* Compile with MEDIUM_MEM to reduce the memory requirements or
* with SMALL_MEM to use as little memory as possible. Use BIG_MEM if the
* entire input file can be held in memory (not possible on 16 bit systems).
* Warning: defining these symbols affects HASH_BITS (see below) and thus
* affects the compression ratio. The compressed output
* is still correct, and might even be smaller in some cases.
*/
#ifdef SMALL_MEM
# define HASH_BITS 13 /* Number of bits used to hash strings */
#endif
#ifdef MEDIUM_MEM
# define HASH_BITS 14
#endif
#ifndef HASH_BITS
# define HASH_BITS 15
/* For portability to 16 bit machines, do not use values above 15. */
#endif
#define HASH_SIZE (unsigned)(1<<HASH_BITS)
#define HASH_MASK (HASH_SIZE-1)
#define WMASK (WSIZE-1)
/* HASH_SIZE and WSIZE must be powers of two */
#ifndef TOO_FAR
# define TOO_FAR 4096
#endif
/* Matches of length 3 are discarded if their distance exceeds TOO_FAR */
/* ===========================================================================
* These types are not really 'char', 'short' and 'long'
*/
typedef uint8_t uch;
typedef uint16_t ush;
typedef uint32_t ulg;
typedef int32_t lng;
typedef ush Pos;
typedef unsigned IPos;
/* A Pos is an index in the character window. We use short instead of int to
* save space in the various tables. IPos is used only for parameter passing.
*/
enum {
WINDOW_SIZE = 2 * WSIZE,
/* window size, 2*WSIZE except for MMAP or BIG_MEM, where it is the
* input file length plus MIN_LOOKAHEAD.
*/
#ifndef ENABLE_FEATURE_GZIP_LEVELS
max_chain_length = 4096,
/* To speed up deflation, hash chains are never searched beyond this length.
* A higher limit improves compression ratio but degrades the speed.
*/
max_lazy_match = 258,
/* Attempt to find a better match only when the current match is strictly
* smaller than this value. This mechanism is used only for compression
* levels >= 4.
*/
max_insert_length = max_lazy_match,
/* Insert new strings in the hash table only if the match length
* is not greater than this length. This saves time but degrades compression.
* max_insert_length is used only for compression levels <= 3.
*/
good_match = 32,
/* Use a faster search when the previous match is longer than this */
/* Values for max_lazy_match, good_match and max_chain_length, depending on
* the desired pack level (0..9). The values given below have been tuned to
* exclude worst case performance for pathological files. Better values may be
* found for specific files.
*/
nice_match = 258, /* Stop searching when current match exceeds this */
/* Note: the deflate() code requires max_lazy >= MIN_MATCH and max_chain >= 4
* For deflate_fast() (levels <= 3) good is ignored and lazy has a different
* meaning.
*/
#endif /* ENABLE_FEATURE_GZIP_LEVELS */
};
struct globals {
#ifdef ENABLE_FEATURE_GZIP_LEVELS
unsigned max_chain_length;
unsigned max_lazy_match;
unsigned good_match;
unsigned nice_match;
#define max_chain_length (G1.max_chain_length)
#define max_lazy_match (G1.max_lazy_match)
#define good_match (G1.good_match)
#define nice_match (G1.nice_match)
#endif
lng block_start;
/* window position at the beginning of the current output block. Gets
* negative when the window is moved backwards.
*/
unsigned ins_h; /* hash index of string to be inserted */
#define H_SHIFT ((HASH_BITS+MIN_MATCH-1) / MIN_MATCH)
/* Number of bits by which ins_h and del_h must be shifted at each
* input step. It must be such that after MIN_MATCH steps, the oldest
* byte no longer takes part in the hash key, that is:
* H_SHIFT * MIN_MATCH >= HASH_BITS
*/
unsigned prev_length;
/* Length of the best match at previous step. Matches not greater than this
* are discarded. This is used in the lazy match evaluation.
*/
unsigned strstart; /* start of string to insert */
unsigned match_start; /* start of matching string */
unsigned lookahead; /* number of valid bytes ahead in window */
/* ===========================================================================
*/
#define DECLARE(type, array, size) \
type * array
#define ALLOC(type, array, size) \
array = xzalloc((size_t)(((size)+1L)/2) * 2*sizeof(type))
#define FREE(array) \
do { free(array); array = NULL; } while (0)
/* global buffers */
/* buffer for literals or lengths */
/* DECLARE(uch, l_buf, LIT_BUFSIZE); */
DECLARE(uch, l_buf, INBUFSIZ);
DECLARE(ush, d_buf, DIST_BUFSIZE);
DECLARE(uch, outbuf, OUTBUFSIZ);
/* Sliding window. Input bytes are read into the second half of the window,
* and move to the first half later to keep a dictionary of at least WSIZE
* bytes. With this organization, matches are limited to a distance of
* WSIZE-MAX_MATCH bytes, but this ensures that IO is always
* performed with a length multiple of the block size. Also, it limits
* the window size to 64K, which is quite useful on MSDOS.
* To do: limit the window size to WSIZE+BSZ if SMALL_MEM (the code would
* be less efficient).
*/
DECLARE(uch, window, 2L * WSIZE);
/* Link to older string with same hash index. To limit the size of this
* array to 64K, this link is maintained only for the last 32K strings.
* An index in this array is thus a window index modulo 32K.
*/
/* DECLARE(Pos, prev, WSIZE); */
DECLARE(ush, prev, 1L << BITS);
/* Heads of the hash chains or 0. */
/* DECLARE(Pos, head, 1<<HASH_BITS); */
#define head (G1.prev + WSIZE) /* hash head (see deflate.c) */
/* number of input bytes */
ulg isize; /* only 32 bits stored in .gz file */
/* bbox always use stdin/stdout */
#define ifd STDIN_FILENO /* input file descriptor */
#define ofd STDOUT_FILENO /* output file descriptor */
#ifdef DEBUG
unsigned insize; /* valid bytes in l_buf */
#endif
unsigned outcnt; /* bytes in output buffer */
smallint eofile; /* flag set at end of input file */
/* ===========================================================================
* Local data used by the "bit string" routines.
*/
unsigned short bi_buf;
/* Output buffer. bits are inserted starting at the bottom (least significant
* bits).
*/
#undef BUF_SIZE
#define BUF_SIZE (8 * sizeof(G1.bi_buf))
/* Number of bits used within bi_buf. (bi_buf might be implemented on
* more than 16 bits on some systems.)
*/
int bi_valid;
/* Current input function. Set to mem_read for in-memory compression */
#ifdef DEBUG
ulg bits_sent; /* bit length of the compressed data */
#endif
/*uint32_t *crc_32_tab;*/
uint32_t crc; /* shift register contents */
};
#define G1 (*(ptr_to_globals - 1))
/* ===========================================================================
* Write the output buffer outbuf[0..outcnt-1] and update bytes_out.
* (used for the compressed data only)
*/
static void flush_outbuf(void)
{
if (G1.outcnt == 0)
return;
xwrite(ofd, (char *) G1.outbuf, G1.outcnt);
G1.outcnt = 0;
}
/* ===========================================================================
*/
/* put_8bit is used for the compressed output */
#define put_8bit(c) \
do { \
G1.outbuf[G1.outcnt++] = (c); \
if (G1.outcnt == OUTBUFSIZ) \
flush_outbuf(); \
} while (0)
/* Output a 16 bit value, lsb first */
static void put_16bit(ush w)
{
/* GCC 4.2.1 won't optimize out redundant loads of G1.outcnt
* (probably because of fear of aliasing with G1.outbuf[]
* stores), do it explicitly:
*/
unsigned outcnt = G1.outcnt;
uch *dst = &G1.outbuf[outcnt];
#if BB_UNALIGNED_MEMACCESS_OK && BB_LITTLE_ENDIAN
if (outcnt < OUTBUFSIZ-2) {
/* Common case */
ush *dst16 = (void*) dst;
*dst16 = w; /* unalinged LSB 16-bit store */
G1.outcnt = outcnt + 2;
return;
}
*dst = (uch)w;
w >>= 8;
#else
*dst = (uch)w;
w >>= 8;
if (outcnt < OUTBUFSIZ-2) {
/* Common case */
dst[1] = w;
G1.outcnt = outcnt + 2;
return;
}
#endif
/* Slowpath: we will need to do flush_outbuf() */
G1.outcnt = ++outcnt;
if (outcnt == OUTBUFSIZ)
flush_outbuf();
put_8bit(w);
}
static void put_32bit(ulg n)
{
put_16bit(n);
put_16bit(n >> 16);
}
/* ===========================================================================
* Run a set of bytes through the crc shift register. If s is a NULL
* pointer, then initialize the crc shift register contents instead.
* Return the current crc in either case.
*/
static void updcrc(uch * s, unsigned n)
{
G1.crc = crc32_block_endian0(G1.crc, s, n, global_crc32_table /*G1.crc_32_tab*/);
}
/* ===========================================================================
* Read a new buffer from the current input file, perform end-of-line
* translation, and update the crc and input file size.
* IN assertion: size >= 2 (for end-of-line translation)
*/
static unsigned file_read(void *buf, unsigned size)
{
unsigned len;
Assert(G1.insize == 0, "l_buf not empty");
len = safe_read(ifd, buf, size);
if (len == (unsigned)(-1) || len == 0)
return len;
updcrc(buf, len);
G1.isize += len;
return len;
}
/* ===========================================================================
* Send a value on a given number of bits.
* IN assertion: length <= 16 and value fits in length bits.
*/
static void send_bits(int value, int length)
{
#ifdef DEBUG
Tracev((stderr, " l %2d v %4x ", length, value));
Assert(length > 0 && length <= 15, "invalid length");
G1.bits_sent += length;
#endif
/* If not enough room in bi_buf, use (valid) bits from bi_buf and
* (16 - bi_valid) bits from value, leaving (width - (16-bi_valid))
* unused bits in value.
*/
if (G1.bi_valid > (int) BUF_SIZE - length) {
G1.bi_buf |= (value << G1.bi_valid);
put_16bit(G1.bi_buf);
G1.bi_buf = (ush) value >> (BUF_SIZE - G1.bi_valid);
G1.bi_valid += length - BUF_SIZE;
} else {
G1.bi_buf |= value << G1.bi_valid;
G1.bi_valid += length;
}
}
/* ===========================================================================
* Reverse the first len bits of a code, using straightforward code (a faster
* method would use a table)
* IN assertion: 1 <= len <= 15
*/
static unsigned bi_reverse(unsigned code, int len)
{
unsigned res = 0;
while (1) {
res |= code & 1;
if (--len <= 0) return res;
code >>= 1;
res <<= 1;
}
}
/* ===========================================================================
* Write out any remaining bits in an incomplete byte.
*/
static void bi_windup(void)
{
if (G1.bi_valid > 8) {
put_16bit(G1.bi_buf);
} else if (G1.bi_valid > 0) {
put_8bit(G1.bi_buf);
}
G1.bi_buf = 0;
G1.bi_valid = 0;
#ifdef DEBUG
G1.bits_sent = (G1.bits_sent + 7) & ~7;
#endif
}
/* ===========================================================================
* Copy a stored block to the zip file, storing first the length and its
* one's complement if requested.
*/
static void copy_block(char *buf, unsigned len, int header)
{
bi_windup(); /* align on byte boundary */
if (header) {
put_16bit(len);
put_16bit(~len);
#ifdef DEBUG
G1.bits_sent += 2 * 16;
#endif
}
#ifdef DEBUG
G1.bits_sent += (ulg) len << 3;
#endif
while (len--) {
put_8bit(*buf++);
}
}
/* ===========================================================================
* Fill the window when the lookahead becomes insufficient.
* Updates strstart and lookahead, and sets eofile if end of input file.
* IN assertion: lookahead < MIN_LOOKAHEAD && strstart + lookahead > 0
* OUT assertions: at least one byte has been read, or eofile is set;
* file reads are performed for at least two bytes (required for the
* translate_eol option).
*/
static void fill_window(void)
{
unsigned n, m;
unsigned more = WINDOW_SIZE - G1.lookahead - G1.strstart;
/* Amount of free space at the end of the window. */
/* If the window is almost full and there is insufficient lookahead,
* move the upper half to the lower one to make room in the upper half.
*/
if (more == (unsigned) -1) {
/* Very unlikely, but possible on 16 bit machine if strstart == 0
* and lookahead == 1 (input done one byte at time)
*/
more--;
} else if (G1.strstart >= WSIZE + MAX_DIST) {
/* By the IN assertion, the window is not empty so we can't confuse
* more == 0 with more == 64K on a 16 bit machine.
*/
Assert(WINDOW_SIZE == 2 * WSIZE, "no sliding with BIG_MEM");
memcpy(G1.window, G1.window + WSIZE, WSIZE);
G1.match_start -= WSIZE;
G1.strstart -= WSIZE; /* we now have strstart >= MAX_DIST: */
G1.block_start -= WSIZE;
for (n = 0; n < HASH_SIZE; n++) {
m = head[n];
head[n] = (Pos) (m >= WSIZE ? m - WSIZE : 0);
}
for (n = 0; n < WSIZE; n++) {
m = G1.prev[n];
G1.prev[n] = (Pos) (m >= WSIZE ? m - WSIZE : 0);
/* If n is not on any hash chain, prev[n] is garbage but
* its value will never be used.
*/
}
more += WSIZE;
}
/* At this point, more >= 2 */
if (!G1.eofile) {
n = file_read(G1.window + G1.strstart + G1.lookahead, more);
if (n == 0 || n == (unsigned) -1) {
G1.eofile = 1;
} else {
G1.lookahead += n;
}
}
}
/* ===========================================================================
* Set match_start to the longest match starting at the given string and
* return its length. Matches shorter or equal to prev_length are discarded,
* in which case the result is equal to prev_length and match_start is
* garbage.
* IN assertions: cur_match is the head of the hash chain for the current
* string (strstart) and its distance is <= MAX_DIST, and prev_length >= 1
*/
/* For MSDOS, OS/2 and 386 Unix, an optimized version is in match.asm or
* match.s. The code is functionally equivalent, so you can use the C version
* if desired.
*/
static int longest_match(IPos cur_match)
{
unsigned chain_length = max_chain_length; /* max hash chain length */
uch *scan = G1.window + G1.strstart; /* current string */
uch *match; /* matched string */
int len; /* length of current match */
int best_len = G1.prev_length; /* best match length so far */
IPos limit = G1.strstart > (IPos) MAX_DIST ? G1.strstart - (IPos) MAX_DIST : 0;
/* Stop when cur_match becomes <= limit. To simplify the code,
* we prevent matches with the string of window index 0.
*/
/* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16.
* It is easy to get rid of this optimization if necessary.
*/
#if HASH_BITS < 8 || MAX_MATCH != 258
# error Code too clever
#endif
uch *strend = G1.window + G1.strstart + MAX_MATCH;
uch scan_end1 = scan[best_len - 1];
uch scan_end = scan[best_len];
/* Do not waste too much time if we already have a good match: */
if (G1.prev_length >= good_match) {
chain_length >>= 2;
}
Assert(G1.strstart <= WINDOW_SIZE - MIN_LOOKAHEAD, "insufficient lookahead");
do {
Assert(cur_match < G1.strstart, "no future");
match = G1.window + cur_match;
/* Skip to next match if the match length cannot increase
* or if the match length is less than 2:
*/
if (match[best_len] != scan_end
|| match[best_len - 1] != scan_end1
|| *match != *scan || *++match != scan[1]
) {
continue;
}
/* The check at best_len-1 can be removed because it will be made
* again later. (This heuristic is not always a win.)
* It is not necessary to compare scan[2] and match[2] since they
* are always equal when the other bytes match, given that
* the hash keys are equal and that HASH_BITS >= 8.
*/
scan += 2, match++;
/* We check for insufficient lookahead only every 8th comparison;
* the 256th check will be made at strstart+258.
*/
do {
} while (*++scan == *++match && *++scan == *++match &&
*++scan == *++match && *++scan == *++match &&
*++scan == *++match && *++scan == *++match &&
*++scan == *++match && *++scan == *++match && scan < strend);
len = MAX_MATCH - (int) (strend - scan);
scan = strend - MAX_MATCH;
if (len > best_len) {
G1.match_start = cur_match;
best_len = len;
if (len >= nice_match)
break;
scan_end1 = scan[best_len - 1];
scan_end = scan[best_len];
}
} while ((cur_match = G1.prev[cur_match & WMASK]) > limit
&& --chain_length != 0);
return best_len;
}
#ifdef DEBUG
/* ===========================================================================
* Check that the match at match_start is indeed a match.
*/
static void check_match(IPos start, IPos match, int length)
{
/* check that the match is indeed a match */
if (memcmp(G1.window + match, G1.window + start, length) != 0) {
bb_error_msg(" start %d, match %d, length %d", start, match, length);
bb_error_msg("invalid match");
}
if (verbose > 1) {
bb_error_msg("\\[%d,%d]", start - match, length);
do {
bb_putchar_stderr(G1.window[start++]);
} while (--length != 0);
}
}
#else
# define check_match(start, match, length) ((void)0)
#endif
/* trees.c -- output deflated data using Huffman coding
* Copyright (C) 1992-1993 Jean-loup Gailly
* This is free software; you can redistribute it and/or modify it under the
* terms of the GNU General Public License, see the file COPYING.
*/
/* PURPOSE
* Encode various sets of source values using variable-length
* binary code trees.
*
* DISCUSSION
* The PKZIP "deflation" process uses several Huffman trees. The more
* common source values are represented by shorter bit sequences.
*
* Each code tree is stored in the ZIP file in a compressed form
* which is itself a Huffman encoding of the lengths of
* all the code strings (in ascending order by source values).
* The actual code strings are reconstructed from the lengths in
* the UNZIP process, as described in the "application note"
* (APPNOTE.TXT) distributed as part of PKWARE's PKZIP program.
*
* REFERENCES
* Lynch, Thomas J.
* Data Compression: Techniques and Applications, pp. 53-55.
* Lifetime Learning Publications, 1985. ISBN 0-534-03418-7.
*
* Storer, James A.
* Data Compression: Methods and Theory, pp. 49-50.
* Computer Science Press, 1988. ISBN 0-7167-8156-5.
*
* Sedgewick, R.
* Algorithms, p290.
* Addison-Wesley, 1983. ISBN 0-201-06672-6.
*
* INTERFACE
* void ct_init()
* Allocate the match buffer, initialize the various tables [and save
* the location of the internal file attribute (ascii/binary) and
* method (DEFLATE/STORE) -- deleted in bbox]
*
* void ct_tally(int dist, int lc);
* Save the match info and tally the frequency counts.
*
* ulg flush_block(char *buf, ulg stored_len, int eof)
* Determine the best encoding for the current block: dynamic trees,
* static trees or store, and output the encoded block to the zip
* file. Returns the total compressed length for the file so far.
*/
#define MAX_BITS 15
/* All codes must not exceed MAX_BITS bits */
#define MAX_BL_BITS 7
/* Bit length codes must not exceed MAX_BL_BITS bits */
#define LENGTH_CODES 29
/* number of length codes, not counting the special END_BLOCK code */
#define LITERALS 256
/* number of literal bytes 0..255 */
#define END_BLOCK 256
/* end of block literal code */
#define L_CODES (LITERALS+1+LENGTH_CODES)
/* number of Literal or Length codes, including the END_BLOCK code */
#define D_CODES 30
/* number of distance codes */
#define BL_CODES 19
/* number of codes used to transfer the bit lengths */
/* extra bits for each length code */
static const uint8_t extra_lbits[LENGTH_CODES] ALIGN1 = {
0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4,
4, 4, 5, 5, 5, 5, 0
};
/* extra bits for each distance code */
static const uint8_t extra_dbits[D_CODES] ALIGN1 = {
0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6, 7, 7, 8, 8, 9, 9,
10, 10, 11, 11, 12, 12, 13, 13
};
/* extra bits for each bit length code */
static const uint8_t extra_blbits[BL_CODES] ALIGN1 = {
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 3, 7 };
/* number of codes at each bit length for an optimal tree */
static const uint8_t bl_order[BL_CODES] ALIGN1 = {
16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15 };
#define STORED_BLOCK 0
#define STATIC_TREES 1
#define DYN_TREES 2
/* The three kinds of block type */
#ifndef LIT_BUFSIZE
# ifdef SMALL_MEM
# define LIT_BUFSIZE 0x2000
# else
# ifdef MEDIUM_MEM
# define LIT_BUFSIZE 0x4000
# else
# define LIT_BUFSIZE 0x8000
# endif
# endif
#endif
#ifndef DIST_BUFSIZE
# define DIST_BUFSIZE LIT_BUFSIZE
#endif
/* Sizes of match buffers for literals/lengths and distances. There are
* 4 reasons for limiting LIT_BUFSIZE to 64K:
* - frequencies can be kept in 16 bit counters
* - if compression is not successful for the first block, all input data is
* still in the window so we can still emit a stored block even when input
* comes from standard input. (This can also be done for all blocks if
* LIT_BUFSIZE is not greater than 32K.)
* - if compression is not successful for a file smaller than 64K, we can
* even emit a stored file instead of a stored block (saving 5 bytes).
* - creating new Huffman trees less frequently may not provide fast
* adaptation to changes in the input data statistics. (Take for
* example a binary file with poorly compressible code followed by
* a highly compressible string table.) Smaller buffer sizes give
* fast adaptation but have of course the overhead of transmitting trees
* more frequently.
* - I can't count above 4
* The current code is general and allows DIST_BUFSIZE < LIT_BUFSIZE (to save
* memory at the expense of compression). Some optimizations would be possible
* if we rely on DIST_BUFSIZE == LIT_BUFSIZE.
*/
#define REP_3_6 16
/* repeat previous bit length 3-6 times (2 bits of repeat count) */
#define REPZ_3_10 17
/* repeat a zero length 3-10 times (3 bits of repeat count) */
#define REPZ_11_138 18
/* repeat a zero length 11-138 times (7 bits of repeat count) */
/* ===========================================================================
*/
/* Data structure describing a single value and its code string. */
typedef struct ct_data {
union {
ush freq; /* frequency count */
ush code; /* bit string */
} fc;
union {
ush dad; /* father node in Huffman tree */
ush len; /* length of bit string */
} dl;
} ct_data;
#define Freq fc.freq
#define Code fc.code
#define Dad dl.dad
#define Len dl.len
#define HEAP_SIZE (2*L_CODES + 1)
/* maximum heap size */
typedef struct tree_desc {
ct_data *dyn_tree; /* the dynamic tree */
ct_data *static_tree; /* corresponding static tree or NULL */
const uint8_t *extra_bits; /* extra bits for each code or NULL */
int extra_base; /* base index for extra_bits */
int elems; /* max number of elements in the tree */
int max_length; /* max bit length for the codes */
int max_code; /* largest code with non zero frequency */
} tree_desc;
struct globals2 {
ush heap[HEAP_SIZE]; /* heap used to build the Huffman trees */
int heap_len; /* number of elements in the heap */
int heap_max; /* element of largest frequency */
/* The sons of heap[n] are heap[2*n] and heap[2*n+1]. heap[0] is not used.
* The same heap array is used to build all trees.
*/
ct_data dyn_ltree[HEAP_SIZE]; /* literal and length tree */
ct_data dyn_dtree[2 * D_CODES + 1]; /* distance tree */
ct_data static_ltree[L_CODES + 2];
/* The static literal tree. Since the bit lengths are imposed, there is no
* need for the L_CODES extra codes used during heap construction. However
* The codes 286 and 287 are needed to build a canonical tree (see ct_init
* below).
*/
ct_data static_dtree[D_CODES];
/* The static distance tree. (Actually a trivial tree since all codes use
* 5 bits.)
*/
ct_data bl_tree[2 * BL_CODES + 1];
/* Huffman tree for the bit lengths */
tree_desc l_desc;
tree_desc d_desc;
tree_desc bl_desc;
ush bl_count[MAX_BITS + 1];
/* The lengths of the bit length codes are sent in order of decreasing
* probability, to avoid transmitting the lengths for unused bit length codes.
*/
uch depth[2 * L_CODES + 1];
/* Depth of each subtree used as tie breaker for trees of equal frequency */
uch length_code[MAX_MATCH - MIN_MATCH + 1];
/* length code for each normalized match length (0 == MIN_MATCH) */
uch dist_code[512];
/* distance codes. The first 256 values correspond to the distances
* 3 .. 258, the last 256 values correspond to the top 8 bits of
* the 15 bit distances.
*/
int base_length[LENGTH_CODES];
/* First normalized length for each code (0 = MIN_MATCH) */
int base_dist[D_CODES];
/* First normalized distance for each code (0 = distance of 1) */
uch flag_buf[LIT_BUFSIZE / 8];
/* flag_buf is a bit array distinguishing literals from lengths in
* l_buf, thus indicating the presence or absence of a distance.
*/
unsigned last_lit; /* running index in l_buf */
unsigned last_dist; /* running index in d_buf */
unsigned last_flags; /* running index in flag_buf */
uch flags; /* current flags not yet saved in flag_buf */
uch flag_bit; /* current bit used in flags */
/* bits are filled in flags starting at bit 0 (least significant).
* Note: these flags are overkill in the current code since we don't
* take advantage of DIST_BUFSIZE == LIT_BUFSIZE.
*/
ulg opt_len; /* bit length of current block with optimal trees */
ulg static_len; /* bit length of current block with static trees */
ulg compressed_len; /* total bit length of compressed file */
};
#define G2ptr ((struct globals2*)(ptr_to_globals))
#define G2 (*G2ptr)
/* ===========================================================================
*/
static void gen_codes(ct_data * tree, int max_code);
static void build_tree(tree_desc * desc);
static void scan_tree(ct_data * tree, int max_code);
static void send_tree(ct_data * tree, int max_code);
static int build_bl_tree(void);
static void send_all_trees(int lcodes, int dcodes, int blcodes);
static void compress_block(ct_data * ltree, ct_data * dtree);
#ifndef DEBUG
/* Send a code of the given tree. c and tree must not have side effects */
# define SEND_CODE(c, tree) send_bits(tree[c].Code, tree[c].Len)
#else
# define SEND_CODE(c, tree) \
{ \
if (verbose > 1) bb_error_msg("\ncd %3d ", (c)); \
send_bits(tree[c].Code, tree[c].Len); \
}
#endif
#define D_CODE(dist) \
((dist) < 256 ? G2.dist_code[dist] : G2.dist_code[256 + ((dist)>>7)])
/* Mapping from a distance to a distance code. dist is the distance - 1 and
* must not have side effects. dist_code[256] and dist_code[257] are never
* used.
* The arguments must not have side effects.
*/
/* ===========================================================================
* Initialize a new block.
*/
static void init_block(void)
{
int n; /* iterates over tree elements */
/* Initialize the trees. */
for (n = 0; n < L_CODES; n++)
G2.dyn_ltree[n].Freq = 0;
for (n = 0; n < D_CODES; n++)
G2.dyn_dtree[n].Freq = 0;
for (n = 0; n < BL_CODES; n++)
G2.bl_tree[n].Freq = 0;
G2.dyn_ltree[END_BLOCK].Freq = 1;
G2.opt_len = G2.static_len = 0;
G2.last_lit = G2.last_dist = G2.last_flags = 0;
G2.flags = 0;
G2.flag_bit = 1;
}
/* ===========================================================================
* Restore the heap property by moving down the tree starting at node k,
* exchanging a node with the smallest of its two sons if necessary, stopping
* when the heap property is re-established (each father smaller than its
* two sons).
*/
/* Compares to subtrees, using the tree depth as tie breaker when
* the subtrees have equal frequency. This minimizes the worst case length. */
#define SMALLER(tree, n, m) \
(tree[n].Freq < tree[m].Freq \
|| (tree[n].Freq == tree[m].Freq && G2.depth[n] <= G2.depth[m]))
static void pqdownheap(ct_data * tree, int k)
{
int v = G2.heap[k];
int j = k << 1; /* left son of k */
while (j <= G2.heap_len) {
/* Set j to the smallest of the two sons: */
if (j < G2.heap_len && SMALLER(tree, G2.heap[j + 1], G2.heap[j]))
j++;
/* Exit if v is smaller than both sons */
if (SMALLER(tree, v, G2.heap[j]))
break;
/* Exchange v with the smallest son */
G2.heap[k] = G2.heap[j];
k = j;
/* And continue down the tree, setting j to the left son of k */
j <<= 1;
}
G2.heap[k] = v;
}
/* ===========================================================================
* Compute the optimal bit lengths for a tree and update the total bit length
* for the current block.
* IN assertion: the fields freq and dad are set, heap[heap_max] and
* above are the tree nodes sorted by increasing frequency.
* OUT assertions: the field len is set to the optimal bit length, the
* array bl_count contains the frequencies for each bit length.
* The length opt_len is updated; static_len is also updated if stree is
* not null.
*/
static void gen_bitlen(tree_desc * desc)
{
ct_data *tree = desc->dyn_tree;
const uint8_t *extra = desc->extra_bits;
int base = desc->extra_base;
int max_code = desc->max_code;
int max_length = desc->max_length;
ct_data *stree = desc->static_tree;
int h; /* heap index */
int n, m; /* iterate over the tree elements */
int bits; /* bit length */
int xbits; /* extra bits */
ush f; /* frequency */
int overflow = 0; /* number of elements with bit length too large */
for (bits = 0; bits <= MAX_BITS; bits++)
G2.bl_count[bits] = 0;
/* In a first pass, compute the optimal bit lengths (which may
* overflow in the case of the bit length tree).
*/
tree[G2.heap[G2.heap_max]].Len = 0; /* root of the heap */
for (h = G2.heap_max + 1; h < HEAP_SIZE; h++) {
n = G2.heap[h];
bits = tree[tree[n].Dad].Len + 1;
if (bits > max_length) {
bits = max_length;
overflow++;
}
tree[n].Len = (ush) bits;
/* We overwrite tree[n].Dad which is no longer needed */
if (n > max_code)
continue; /* not a leaf node */
G2.bl_count[bits]++;
xbits = 0;
if (n >= base)
xbits = extra[n - base];
f = tree[n].Freq;
G2.opt_len += (ulg) f *(bits + xbits);
if (stree)
G2.static_len += (ulg) f * (stree[n].Len + xbits);
}
if (overflow == 0)
return;
Trace((stderr, "\nbit length overflow\n"));
/* This happens for example on obj2 and pic of the Calgary corpus */
/* Find the first bit length which could increase: */
do {
bits = max_length - 1;
while (G2.bl_count[bits] == 0)
bits--;
G2.bl_count[bits]--; /* move one leaf down the tree */
G2.bl_count[bits + 1] += 2; /* move one overflow item as its brother */
G2.bl_count[max_length]--;
/* The brother of the overflow item also moves one step up,
* but this does not affect bl_count[max_length]
*/
overflow -= 2;
} while (overflow > 0);
/* Now recompute all bit lengths, scanning in increasing frequency.
* h is still equal to HEAP_SIZE. (It is simpler to reconstruct all
* lengths instead of fixing only the wrong ones. This idea is taken
* from 'ar' written by Haruhiko Okumura.)
*/
for (bits = max_length; bits != 0; bits--) {
n = G2.bl_count[bits];
while (n != 0) {
m = G2.heap[--h];
if (m > max_code)
continue;
if (tree[m].Len != (unsigned) bits) {
Trace((stderr, "code %d bits %d->%d\n", m, tree[m].Len, bits));
G2.opt_len += ((int32_t) bits - tree[m].Len) * tree[m].Freq;
tree[m].Len = bits;
}
n--;
}
}
}
/* ===========================================================================
* Generate the codes for a given tree and bit counts (which need not be
* optimal).
* IN assertion: the array bl_count contains the bit length statistics for
* the given tree and the field len is set for all tree elements.
* OUT assertion: the field code is set for all tree elements of non
* zero code length.
*/
static void gen_codes(ct_data * tree, int max_code)
{
ush next_code[MAX_BITS + 1]; /* next code value for each bit length */
ush code = 0; /* running code value */
int bits; /* bit index */
int n; /* code index */
/* The distribution counts are first used to generate the code values
* without bit reversal.
*/
for (bits = 1; bits <= MAX_BITS; bits++) {
next_code[bits] = code = (code + G2.bl_count[bits - 1]) << 1;
}
/* Check that the bit counts in bl_count are consistent. The last code
* must be all ones.
*/
Assert(code + G2.bl_count[MAX_BITS] - 1 == (1 << MAX_BITS) - 1,
"inconsistent bit counts");
Tracev((stderr, "\ngen_codes: max_code %d ", max_code));
for (n = 0; n <= max_code; n++) {
int len = tree[n].Len;
if (len == 0)
continue;
/* Now reverse the bits */
tree[n].Code = bi_reverse(next_code[len]++, len);
Tracec(tree != G2.static_ltree,
(stderr, "\nn %3d %c l %2d c %4x (%x) ", n,
(n > ' ' ? n : ' '), len, tree[n].Code,
next_code[len] - 1));
}
}
/* ===========================================================================
* Construct one Huffman tree and assigns the code bit strings and lengths.
* Update the total bit length for the current block.
* IN assertion: the field freq is set for all tree elements.
* OUT assertions: the fields len and code are set to the optimal bit length
* and corresponding code. The length opt_len is updated; static_len is
* also updated if stree is not null. The field max_code is set.
*/
/* Remove the smallest element from the heap and recreate the heap with
* one less element. Updates heap and heap_len. */
#define SMALLEST 1
/* Index within the heap array of least frequent node in the Huffman tree */
#define PQREMOVE(tree, top) \
do { \
top = G2.heap[SMALLEST]; \
G2.heap[SMALLEST] = G2.heap[G2.heap_len--]; \
pqdownheap(tree, SMALLEST); \
} while (0)
static void build_tree(tree_desc * desc)
{
ct_data *tree = desc->dyn_tree;
ct_data *stree = desc->static_tree;
int elems = desc->elems;
int n, m; /* iterate over heap elements */
int max_code = -1; /* largest code with non zero frequency */
int node = elems; /* next internal node of the tree */
/* Construct the initial heap, with least frequent element in
* heap[SMALLEST]. The sons of heap[n] are heap[2*n] and heap[2*n+1].
* heap[0] is not used.
*/
G2.heap_len = 0;
G2.heap_max = HEAP_SIZE;
for (n = 0; n < elems; n++) {
if (tree[n].Freq != 0) {
G2.heap[++G2.heap_len] = max_code = n;
G2.depth[n] = 0;
} else {
tree[n].Len = 0;
}
}
/* The pkzip format requires that at least one distance code exists,
* and that at least one bit should be sent even if there is only one
* possible code. So to avoid special checks later on we force at least
* two codes of non zero frequency.
*/
while (G2.heap_len < 2) {
int new = G2.heap[++G2.heap_len] = (max_code < 2 ? ++max_code : 0);
tree[new].Freq = 1;
G2.depth[new] = 0;
G2.opt_len--;
if (stree)
G2.static_len -= stree[new].Len;
/* new is 0 or 1 so it does not have extra bits */
}
desc->max_code = max_code;
/* The elements heap[heap_len/2+1 .. heap_len] are leaves of the tree,
* establish sub-heaps of increasing lengths:
*/
for (n = G2.heap_len / 2; n >= 1; n--)
pqdownheap(tree, n);
/* Construct the Huffman tree by repeatedly combining the least two
* frequent nodes.
*/
do {
PQREMOVE(tree, n); /* n = node of least frequency */
m = G2.heap[SMALLEST]; /* m = node of next least frequency */
G2.heap[--G2.heap_max] = n; /* keep the nodes sorted by frequency */
G2.heap[--G2.heap_max] = m;
/* Create a new node father of n and m */
tree[node].Freq = tree[n].Freq + tree[m].Freq;
G2.depth[node] = MAX(G2.depth[n], G2.depth[m]) + 1;
tree[n].Dad = tree[m].Dad = (ush) node;
#ifdef DUMP_BL_TREE
if (tree == G2.bl_tree) {
bb_error_msg("\nnode %d(%d), sons %d(%d) %d(%d)",
node, tree[node].Freq, n, tree[n].Freq, m, tree[m].Freq);
}
#endif
/* and insert the new node in the heap */
G2.heap[SMALLEST] = node++;
pqdownheap(tree, SMALLEST);
} while (G2.heap_len >= 2);
G2.heap[--G2.heap_max] = G2.heap[SMALLEST];
/* At this point, the fields freq and dad are set. We can now
* generate the bit lengths.
*/
gen_bitlen((tree_desc *) desc);
/* The field len is now set, we can generate the bit codes */
gen_codes((ct_data *) tree, max_code);
}
/* ===========================================================================
* Scan a literal or distance tree to determine the frequencies of the codes
* in the bit length tree. Updates opt_len to take into account the repeat
* counts. (The contribution of the bit length codes will be added later
* during the construction of bl_tree.)
*/
static void scan_tree(ct_data * tree, int max_code)
{
int n; /* iterates over all tree elements */
int prevlen = -1; /* last emitted length */
int curlen; /* length of current code */
int nextlen = tree[0].Len; /* length of next code */
int count = 0; /* repeat count of the current code */
int max_count = 7; /* max repeat count */
int min_count = 4; /* min repeat count */
if (nextlen == 0) {
max_count = 138;
min_count = 3;
}
tree[max_code + 1].Len = 0xffff; /* guard */
for (n = 0; n <= max_code; n++) {
curlen = nextlen;
nextlen = tree[n + 1].Len;
if (++count < max_count && curlen == nextlen)
continue;
if (count < min_count) {
G2.bl_tree[curlen].Freq += count;
} else if (curlen != 0) {
if (curlen != prevlen)
G2.bl_tree[curlen].Freq++;
G2.bl_tree[REP_3_6].Freq++;
} else if (count <= 10) {
G2.bl_tree[REPZ_3_10].Freq++;
} else {
G2.bl_tree[REPZ_11_138].Freq++;
}
count = 0;
prevlen = curlen;
max_count = 7;
min_count = 4;
if (nextlen == 0) {
max_count = 138;
min_count = 3;
} else if (curlen == nextlen) {
max_count = 6;
min_count = 3;
}
}
}
/* ===========================================================================
* Send a literal or distance tree in compressed form, using the codes in
* bl_tree.
*/
static void send_tree(ct_data * tree, int max_code)
{
int n; /* iterates over all tree elements */
int prevlen = -1; /* last emitted length */
int curlen; /* length of current code */
int nextlen = tree[0].Len; /* length of next code */
int count = 0; /* repeat count of the current code */
int max_count = 7; /* max repeat count */
int min_count = 4; /* min repeat count */
/* tree[max_code+1].Len = -1; *//* guard already set */
if (nextlen == 0)
max_count = 138, min_count = 3;
for (n = 0; n <= max_code; n++) {
curlen = nextlen;
nextlen = tree[n + 1].Len;
if (++count < max_count && curlen == nextlen) {
continue;
} else if (count < min_count) {
do {
SEND_CODE(curlen, G2.bl_tree);
} while (--count);
} else if (curlen != 0) {
if (curlen != prevlen) {
SEND_CODE(curlen, G2.bl_tree);
count--;
}
Assert(count >= 3 && count <= 6, " 3_6?");
SEND_CODE(REP_3_6, G2.bl_tree);
send_bits(count - 3, 2);
} else if (count <= 10) {
SEND_CODE(REPZ_3_10, G2.bl_tree);
send_bits(count - 3, 3);
} else {
SEND_CODE(REPZ_11_138, G2.bl_tree);
send_bits(count - 11, 7);
}
count = 0;
prevlen = curlen;
if (nextlen == 0) {
max_count = 138;
min_count = 3;
} else if (curlen == nextlen) {
max_count = 6;
min_count = 3;
} else {
max_count = 7;
min_count = 4;
}
}
}
/* ===========================================================================
* Construct the Huffman tree for the bit lengths and return the index in
* bl_order of the last bit length code to send.
*/
static int build_bl_tree(void)
{
int max_blindex; /* index of last bit length code of non zero freq */
/* Determine the bit length frequencies for literal and distance trees */
scan_tree(G2.dyn_ltree, G2.l_desc.max_code);
scan_tree(G2.dyn_dtree, G2.d_desc.max_code);
/* Build the bit length tree: */
build_tree(&G2.bl_desc);
/* opt_len now includes the length of the tree representations, except
* the lengths of the bit lengths codes and the 5+5+4 bits for the counts.
*/
/* Determine the number of bit length codes to send. The pkzip format
* requires that at least 4 bit length codes be sent. (appnote.txt says
* 3 but the actual value used is 4.)
*/
for (max_blindex = BL_CODES - 1; max_blindex >= 3; max_blindex--) {
if (G2.bl_tree[bl_order[max_blindex]].Len != 0)
break;
}
/* Update opt_len to include the bit length tree and counts */
G2.opt_len += 3 * (max_blindex + 1) + 5 + 5 + 4;
Tracev((stderr, "\ndyn trees: dyn %ld, stat %ld", G2.opt_len, G2.static_len));
return max_blindex;
}
/* ===========================================================================
* Send the header for a block using dynamic Huffman trees: the counts, the
* lengths of the bit length codes, the literal tree and the distance tree.
* IN assertion: lcodes >= 257, dcodes >= 1, blcodes >= 4.
*/
static void send_all_trees(int lcodes, int dcodes, int blcodes)
{
int rank; /* index in bl_order */
Assert(lcodes >= 257 && dcodes >= 1 && blcodes >= 4, "not enough codes");
Assert(lcodes <= L_CODES && dcodes <= D_CODES
&& blcodes <= BL_CODES, "too many codes");
Tracev((stderr, "\nbl counts: "));
send_bits(lcodes - 257, 5); /* not +255 as stated in appnote.txt */
send_bits(dcodes - 1, 5);
send_bits(blcodes - 4, 4); /* not -3 as stated in appnote.txt */
for (rank = 0; rank < blcodes; rank++) {
Tracev((stderr, "\nbl code %2d ", bl_order[rank]));
send_bits(G2.bl_tree[bl_order[rank]].Len, 3);
}
Tracev((stderr, "\nbl tree: sent %ld", G1.bits_sent));
send_tree((ct_data *) G2.dyn_ltree, lcodes - 1); /* send the literal tree */
Tracev((stderr, "\nlit tree: sent %ld", G1.bits_sent));
send_tree((ct_data *) G2.dyn_dtree, dcodes - 1); /* send the distance tree */
Tracev((stderr, "\ndist tree: sent %ld", G1.bits_sent));
}
/* ===========================================================================
* Save the match info and tally the frequency counts. Return true if
* the current block must be flushed.
*/
static int ct_tally(int dist, int lc)
{
G1.l_buf[G2.last_lit++] = lc;
if (dist == 0) {
/* lc is the unmatched char */
G2.dyn_ltree[lc].Freq++;
} else {
/* Here, lc is the match length - MIN_MATCH */
dist--; /* dist = match distance - 1 */
Assert((ush) dist < (ush) MAX_DIST
&& (ush) lc <= (ush) (MAX_MATCH - MIN_MATCH)
&& (ush) D_CODE(dist) < (ush) D_CODES, "ct_tally: bad match"
);
G2.dyn_ltree[G2.length_code[lc] + LITERALS + 1].Freq++;
G2.dyn_dtree[D_CODE(dist)].Freq++;
G1.d_buf[G2.last_dist++] = dist;
G2.flags |= G2.flag_bit;
}
G2.flag_bit <<= 1;
/* Output the flags if they fill a byte: */
if ((G2.last_lit & 7) == 0) {
G2.flag_buf[G2.last_flags++] = G2.flags;
G2.flags = 0;
G2.flag_bit = 1;
}
/* Try to guess if it is profitable to stop the current block here */
if ((G2.last_lit & 0xfff) == 0) {
/* Compute an upper bound for the compressed length */
ulg out_length = G2.last_lit * 8L;
ulg in_length = (ulg) G1.strstart - G1.block_start;
int dcode;
for (dcode = 0; dcode < D_CODES; dcode++) {
out_length += G2.dyn_dtree[dcode].Freq * (5L + extra_dbits[dcode]);
}
out_length >>= 3;
Trace((stderr,
"\nlast_lit %u, last_dist %u, in %ld, out ~%ld(%ld%%) ",
G2.last_lit, G2.last_dist, in_length, out_length,
100L - out_length * 100L / in_length));
if (G2.last_dist < G2.last_lit / 2 && out_length < in_length / 2)
return 1;
}
return (G2.last_lit == LIT_BUFSIZE - 1 || G2.last_dist == DIST_BUFSIZE);
/* We avoid equality with LIT_BUFSIZE because of wraparound at 64K
* on 16 bit machines and because stored blocks are restricted to
* 64K-1 bytes.
*/
}
/* ===========================================================================
* Send the block data compressed using the given Huffman trees
*/
static void compress_block(ct_data * ltree, ct_data * dtree)
{
unsigned dist; /* distance of matched string */
int lc; /* match length or unmatched char (if dist == 0) */
unsigned lx = 0; /* running index in l_buf */
unsigned dx = 0; /* running index in d_buf */
unsigned fx = 0; /* running index in flag_buf */
uch flag = 0; /* current flags */
unsigned code; /* the code to send */
int extra; /* number of extra bits to send */
if (G2.last_lit != 0) do {
if ((lx & 7) == 0)
flag = G2.flag_buf[fx++];
lc = G1.l_buf[lx++];
if ((flag & 1) == 0) {
SEND_CODE(lc, ltree); /* send a literal byte */
Tracecv(lc > ' ', (stderr, " '%c' ", lc));
} else {
/* Here, lc is the match length - MIN_MATCH */
code = G2.length_code[lc];
SEND_CODE(code + LITERALS + 1, ltree); /* send the length code */
extra = extra_lbits[code];
if (extra != 0) {
lc -= G2.base_length[code];
send_bits(lc, extra); /* send the extra length bits */
}
dist = G1.d_buf[dx++];
/* Here, dist is the match distance - 1 */
code = D_CODE(dist);
Assert(code < D_CODES, "bad d_code");
SEND_CODE(code, dtree); /* send the distance code */
extra = extra_dbits[code];
if (extra != 0) {
dist -= G2.base_dist[code];
send_bits(dist, extra); /* send the extra distance bits */
}
} /* literal or match pair ? */
flag >>= 1;
} while (lx < G2.last_lit);
SEND_CODE(END_BLOCK, ltree);
}
/* ===========================================================================
* Determine the best encoding for the current block: dynamic trees, static
* trees or store, and output the encoded block to the zip file. This function
* returns the total compressed length for the file so far.
*/
static ulg flush_block(char *buf, ulg stored_len, int eof)
{
ulg opt_lenb, static_lenb; /* opt_len and static_len in bytes */
int max_blindex; /* index of last bit length code of non zero freq */
G2.flag_buf[G2.last_flags] = G2.flags; /* Save the flags for the last 8 items */
/* Construct the literal and distance trees */
build_tree(&G2.l_desc);
Tracev((stderr, "\nlit data: dyn %ld, stat %ld", G2.opt_len, G2.static_len));
build_tree(&G2.d_desc);
Tracev((stderr, "\ndist data: dyn %ld, stat %ld", G2.opt_len, G2.static_len));
/* At this point, opt_len and static_len are the total bit lengths of
* the compressed block data, excluding the tree representations.
*/
/* Build the bit length tree for the above two trees, and get the index
* in bl_order of the last bit length code to send.
*/
max_blindex = build_bl_tree();
/* Determine the best encoding. Compute first the block length in bytes */
opt_lenb = (G2.opt_len + 3 + 7) >> 3;
static_lenb = (G2.static_len + 3 + 7) >> 3;
Trace((stderr,
"\nopt %lu(%lu) stat %lu(%lu) stored %lu lit %u dist %u ",
opt_lenb, G2.opt_len, static_lenb, G2.static_len, stored_len,
G2.last_lit, G2.last_dist));
if (static_lenb <= opt_lenb)
opt_lenb = static_lenb;
/* If compression failed and this is the first and last block,
* and if the zip file can be seeked (to rewrite the local header),
* the whole file is transformed into a stored file:
*/
if (stored_len <= opt_lenb && eof && G2.compressed_len == 0L && seekable()) {
/* Since LIT_BUFSIZE <= 2*WSIZE, the input data must be there: */
if (buf == NULL)
bb_error_msg("block vanished");
copy_block(buf, (unsigned) stored_len, 0); /* without header */
G2.compressed_len = stored_len << 3;
} else if (stored_len + 4 <= opt_lenb && buf != NULL) {
/* 4: two words for the lengths */
/* The test buf != NULL is only necessary if LIT_BUFSIZE > WSIZE.
* Otherwise we can't have processed more than WSIZE input bytes since
* the last block flush, because compression would have been
* successful. If LIT_BUFSIZE <= WSIZE, it is never too late to
* transform a block into a stored block.
*/
send_bits((STORED_BLOCK << 1) + eof, 3); /* send block type */
G2.compressed_len = (G2.compressed_len + 3 + 7) & ~7L;
G2.compressed_len += (stored_len + 4) << 3;
copy_block(buf, (unsigned) stored_len, 1); /* with header */
} else if (static_lenb == opt_lenb) {
send_bits((STATIC_TREES << 1) + eof, 3);
compress_block((ct_data *) G2.static_ltree, (ct_data *) G2.static_dtree);
G2.compressed_len += 3 + G2.static_len;
} else {
send_bits((DYN_TREES << 1) + eof, 3);
send_all_trees(G2.l_desc.max_code + 1, G2.d_desc.max_code + 1,
max_blindex + 1);
compress_block((ct_data *) G2.dyn_ltree, (ct_data *) G2.dyn_dtree);
G2.compressed_len += 3 + G2.opt_len;
}
Assert(G2.compressed_len == G1.bits_sent, "bad compressed size");
init_block();
if (eof) {
bi_windup();
G2.compressed_len += 7; /* align on byte boundary */
}
Tracev((stderr, "\ncomprlen %lu(%lu) ", G2.compressed_len >> 3,
G2.compressed_len - 7 * eof));
return G2.compressed_len >> 3;
}
/* ===========================================================================
* Update a hash value with the given input byte
* IN assertion: all calls to UPDATE_HASH are made with consecutive
* input characters, so that a running hash key can be computed from the
* previous key instead of complete recalculation each time.
*/
#define UPDATE_HASH(h, c) (h = (((h)<<H_SHIFT) ^ (c)) & HASH_MASK)
/* ===========================================================================
* Same as above, but achieves better compression. We use a lazy
* evaluation for matches: a match is finally adopted only if there is
* no better match at the next window position.
*
* Processes a new input file and return its compressed length. Sets
* the compressed length, crc, deflate flags and internal file
* attributes.
*/
/* Flush the current block, with given end-of-file flag.
* IN assertion: strstart is set to the end of the current match. */
#define FLUSH_BLOCK(eof) \
flush_block( \
G1.block_start >= 0L \
? (char*)&G1.window[(unsigned)G1.block_start] \
: (char*)NULL, \
(ulg)G1.strstart - G1.block_start, \
(eof) \
)
/* Insert string s in the dictionary and set match_head to the previous head
* of the hash chain (the most recent string with same hash key). Return
* the previous length of the hash chain.
* IN assertion: all calls to INSERT_STRING are made with consecutive
* input characters and the first MIN_MATCH bytes of s are valid
* (except for the last MIN_MATCH-1 bytes of the input file). */
#define INSERT_STRING(s, match_head) \
do { \
UPDATE_HASH(G1.ins_h, G1.window[(s) + MIN_MATCH-1]); \
G1.prev[(s) & WMASK] = match_head = head[G1.ins_h]; \
head[G1.ins_h] = (s); \
} while (0)
static ulg deflate(void)
{
IPos hash_head; /* head of hash chain */
IPos prev_match; /* previous match */
int flush; /* set if current block must be flushed */
int match_available = 0; /* set if previous match exists */
unsigned match_length = MIN_MATCH - 1; /* length of best match */
/* Process the input block. */
while (G1.lookahead != 0) {
/* Insert the string window[strstart .. strstart+2] in the
* dictionary, and set hash_head to the head of the hash chain:
*/
INSERT_STRING(G1.strstart, hash_head);
/* Find the longest match, discarding those <= prev_length.
*/
G1.prev_length = match_length;
prev_match = G1.match_start;
match_length = MIN_MATCH - 1;
if (hash_head != 0 && G1.prev_length < max_lazy_match
&& G1.strstart - hash_head <= MAX_DIST
) {
/* To simplify the code, we prevent matches with the string
* of window index 0 (in particular we have to avoid a match
* of the string with itself at the start of the input file).
*/
match_length = longest_match(hash_head);
/* longest_match() sets match_start */
if (match_length > G1.lookahead)
match_length = G1.lookahead;
/* Ignore a length 3 match if it is too distant: */
if (match_length == MIN_MATCH && G1.strstart - G1.match_start > TOO_FAR) {
/* If prev_match is also MIN_MATCH, G1.match_start is garbage
* but we will ignore the current match anyway.
*/
match_length--;
}
}
/* If there was a match at the previous step and the current
* match is not better, output the previous match:
*/
if (G1.prev_length >= MIN_MATCH && match_length <= G1.prev_length) {
check_match(G1.strstart - 1, prev_match, G1.prev_length);
flush = ct_tally(G1.strstart - 1 - prev_match, G1.prev_length - MIN_MATCH);
/* Insert in hash table all strings up to the end of the match.
* strstart-1 and strstart are already inserted.
*/
G1.lookahead -= G1.prev_length - 1;
G1.prev_length -= 2;
do {
G1.strstart++;
INSERT_STRING(G1.strstart, hash_head);
/* strstart never exceeds WSIZE-MAX_MATCH, so there are
* always MIN_MATCH bytes ahead. If lookahead < MIN_MATCH
* these bytes are garbage, but it does not matter since the
* next lookahead bytes will always be emitted as literals.
*/
} while (--G1.prev_length != 0);
match_available = 0;
match_length = MIN_MATCH - 1;
G1.strstart++;
if (flush) {
FLUSH_BLOCK(0);
G1.block_start = G1.strstart;
}
} else if (match_available) {
/* If there was no match at the previous position, output a
* single literal. If there was a match but the current match
* is longer, truncate the previous match to a single literal.
*/
Tracevv((stderr, "%c", G1.window[G1.strstart - 1]));
if (ct_tally(0, G1.window[G1.strstart - 1])) {
FLUSH_BLOCK(0);
G1.block_start = G1.strstart;
}
G1.strstart++;
G1.lookahead--;
} else {
/* There is no previous match to compare with, wait for
* the next step to decide.
*/
match_available = 1;
G1.strstart++;
G1.lookahead--;
}
Assert(G1.strstart <= G1.isize && lookahead <= G1.isize, "a bit too far");
/* Make sure that we always have enough lookahead, except
* at the end of the input file. We need MAX_MATCH bytes
* for the next match, plus MIN_MATCH bytes to insert the
* string following the next match.
*/
while (G1.lookahead < MIN_LOOKAHEAD && !G1.eofile)
fill_window();
}
if (match_available)
ct_tally(0, G1.window[G1.strstart - 1]);
return FLUSH_BLOCK(1); /* eof */
}
/* ===========================================================================
* Initialize the bit string routines.
*/
static void bi_init(void)
{
G1.bi_buf = 0;
G1.bi_valid = 0;
#ifdef DEBUG
G1.bits_sent = 0L;
#endif
}
/* ===========================================================================
* Initialize the "longest match" routines for a new file
*/
static void lm_init(ush * flagsp)
{
unsigned j;
/* Initialize the hash table. */
memset(head, 0, HASH_SIZE * sizeof(*head));
/* prev will be initialized on the fly */
/* speed options for the general purpose bit flag */
*flagsp |= 2; /* FAST 4, SLOW 2 */
/* ??? reduce max_chain_length for binary files */
G1.strstart = 0;
G1.block_start = 0L;
G1.lookahead = file_read(G1.window,
sizeof(int) <= 2 ? (unsigned) WSIZE : 2 * WSIZE);
if (G1.lookahead == 0 || G1.lookahead == (unsigned) -1) {
G1.eofile = 1;
G1.lookahead = 0;
return;
}
G1.eofile = 0;
/* Make sure that we always have enough lookahead. This is important
* if input comes from a device such as a tty.
*/
while (G1.lookahead < MIN_LOOKAHEAD && !G1.eofile)
fill_window();
G1.ins_h = 0;
for (j = 0; j < MIN_MATCH - 1; j++)
UPDATE_HASH(G1.ins_h, G1.window[j]);
/* If lookahead < MIN_MATCH, ins_h is garbage, but this is
* not important since only literal bytes will be emitted.
*/
}
/* ===========================================================================
* Allocate the match buffer, initialize the various tables and save the
* location of the internal file attribute (ascii/binary) and method
* (DEFLATE/STORE).
* One callsite in zip()
*/
static void ct_init(void)
{
int n; /* iterates over tree elements */
int length; /* length value */
int code; /* code value */
int dist; /* distance index */
G2.compressed_len = 0L;
#ifdef NOT_NEEDED
if (G2.static_dtree[0].Len != 0)
return; /* ct_init already called */
#endif
/* Initialize the mapping length (0..255) -> length code (0..28) */
length = 0;
for (code = 0; code < LENGTH_CODES - 1; code++) {
G2.base_length[code] = length;
for (n = 0; n < (1 << extra_lbits[code]); n++) {
G2.length_code[length++] = code;
}
}
Assert(length == 256, "ct_init: length != 256");
/* Note that the length 255 (match length 258) can be represented
* in two different ways: code 284 + 5 bits or code 285, so we
* overwrite length_code[255] to use the best encoding:
*/
G2.length_code[length - 1] = code;
/* Initialize the mapping dist (0..32K) -> dist code (0..29) */
dist = 0;
for (code = 0; code < 16; code++) {
G2.base_dist[code] = dist;
for (n = 0; n < (1 << extra_dbits[code]); n++) {
G2.dist_code[dist++] = code;
}
}
Assert(dist == 256, "ct_init: dist != 256");
dist >>= 7; /* from now on, all distances are divided by 128 */
for (; code < D_CODES; code++) {
G2.base_dist[code] = dist << 7;
for (n = 0; n < (1 << (extra_dbits[code] - 7)); n++) {
G2.dist_code[256 + dist++] = code;
}
}
Assert(dist == 256, "ct_init: 256+dist != 512");
/* Construct the codes of the static literal tree */
/* already zeroed - it's in bss
for (n = 0; n <= MAX_BITS; n++)
G2.bl_count[n] = 0; */
n = 0;
while (n <= 143) {
G2.static_ltree[n++].Len = 8;
G2.bl_count[8]++;
}
while (n <= 255) {
G2.static_ltree[n++].Len = 9;
G2.bl_count[9]++;
}
while (n <= 279) {
G2.static_ltree[n++].Len = 7;
G2.bl_count[7]++;
}
while (n <= 287) {
G2.static_ltree[n++].Len = 8;
G2.bl_count[8]++;
}
/* Codes 286 and 287 do not exist, but we must include them in the
* tree construction to get a canonical Huffman tree (longest code
* all ones)
*/
gen_codes((ct_data *) G2.static_ltree, L_CODES + 1);
/* The static distance tree is trivial: */
for (n = 0; n < D_CODES; n++) {
G2.static_dtree[n].Len = 5;
G2.static_dtree[n].Code = bi_reverse(n, 5);
}
/* Initialize the first block of the first file: */
init_block();
}
/* ===========================================================================
* Deflate in to out.
* IN assertions: the input and output buffers are cleared.
*/
static void zip(void)
{
ush deflate_flags = 0; /* pkzip -es, -en or -ex equivalent */
G1.outcnt = 0;
/* Write the header to the gzip file. See algorithm.doc for the format */
/* magic header for gzip files: 1F 8B */
/* compression method: 8 (DEFLATED) */
/* general flags: 0 */
put_32bit(0x00088b1f);
put_32bit(0); /* Unix timestamp */
/* Write deflated file to zip file */
G1.crc = ~0;
bi_init();
ct_init();
lm_init(&deflate_flags);
put_8bit(deflate_flags); /* extra flags */
put_8bit(3); /* OS identifier = 3 (Unix) */
deflate();
/* Write the crc and uncompressed size */
put_32bit(~G1.crc);
put_32bit(G1.isize);
flush_outbuf();
}
/* ======================================================================== */
static
IF_DESKTOP(long long) int FAST_FUNC pack_gzip(transformer_state_t *xstate UNUSED_PARAM)
{
/* Clear input and output buffers */
G1.outcnt = 0;
#ifdef DEBUG
G1.insize = 0;
#endif
G1.isize = 0;
/* Reinit G2.xxx */
memset(&G2, 0, sizeof(G2));
G2.l_desc.dyn_tree = G2.dyn_ltree;
G2.l_desc.static_tree = G2.static_ltree;
G2.l_desc.extra_bits = extra_lbits;
G2.l_desc.extra_base = LITERALS + 1;
G2.l_desc.elems = L_CODES;
G2.l_desc.max_length = MAX_BITS;
//G2.l_desc.max_code = 0;
G2.d_desc.dyn_tree = G2.dyn_dtree;
G2.d_desc.static_tree = G2.static_dtree;
G2.d_desc.extra_bits = extra_dbits;
//G2.d_desc.extra_base = 0;
G2.d_desc.elems = D_CODES;
G2.d_desc.max_length = MAX_BITS;
//G2.d_desc.max_code = 0;
G2.bl_desc.dyn_tree = G2.bl_tree;
//G2.bl_desc.static_tree = NULL;
G2.bl_desc.extra_bits = extra_blbits,
//G2.bl_desc.extra_base = 0;
G2.bl_desc.elems = BL_CODES;
G2.bl_desc.max_length = MAX_BL_BITS;
//G2.bl_desc.max_code = 0;
#if 0
/* Saving of timestamp is disabled. Why?
* - it is not Y2038-safe.
* - some people want deterministic results
* (normally they'd use -n, but our -n is a nop).
* - it's bloat.
* Per RFC 1952, gzfile.time=0 is "no timestamp".
* If users will demand this to be reinstated,
* implement -n "don't save timestamp".
*/
struct stat s;
s.st_ctime = 0;
fstat(STDIN_FILENO, &s);
zip(s.st_ctime);
#else
zip();
#endif
return 0;
}
#if ENABLE_FEATURE_GZIP_LONG_OPTIONS
static const char gzip_longopts[] ALIGN1 =
"stdout\0" No_argument "c"
"to-stdout\0" No_argument "c"
"force\0" No_argument "f"
"verbose\0" No_argument "v"
#if ENABLE_FEATURE_GZIP_DECOMPRESS
"decompress\0" No_argument "d"
"uncompress\0" No_argument "d"
"test\0" No_argument "t"
#endif
"quiet\0" No_argument "q"
"fast\0" No_argument "1"
"best\0" No_argument "9"
"no-name\0" No_argument "n"
;
#endif
/*
* Linux kernel build uses gzip -d -n. We accept and ignore -n.
* Man page says:
* -n --no-name
* gzip: do not save the original file name and time stamp.
* (The original name is always saved if the name had to be truncated.)
* gunzip: do not restore the original file name/time even if present
* (remove only the gzip suffix from the compressed file name).
* This option is the default when decompressing.
* -N --name
* gzip: always save the original file name and time stamp (this is the default)
* gunzip: restore the original file name and time stamp if present.
*/
int gzip_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
#if ENABLE_FEATURE_GZIP_DECOMPRESS
int gzip_main(int argc, char **argv)
#else
int gzip_main(int argc UNUSED_PARAM, char **argv)
#endif
{
unsigned opt;
#ifdef ENABLE_FEATURE_GZIP_LEVELS
static const struct {
uint8_t good;
uint8_t chain_shift;
uint8_t lazy2;
uint8_t nice2;
} gzip_level_config[6] = {
{4, 4, 4/2, 16/2}, /* Level 4 */
{8, 5, 16/2, 32/2}, /* Level 5 */
{8, 7, 16/2, 128/2}, /* Level 6 */
{8, 8, 32/2, 128/2}, /* Level 7 */
{32, 10, 128/2, 258/2}, /* Level 8 */
{32, 12, 258/2, 258/2}, /* Level 9 */
};
#endif
SET_PTR_TO_GLOBALS((char *)xzalloc(sizeof(struct globals)+sizeof(struct globals2))
+ sizeof(struct globals));
#if ENABLE_FEATURE_GZIP_LONG_OPTIONS
applet_long_options = gzip_longopts;
#endif
/* Must match bbunzip's constants OPT_STDOUT, OPT_FORCE! */
opt = getopt32(argv, "cfv" IF_FEATURE_GZIP_DECOMPRESS("dt") "qn123456789");
#if ENABLE_FEATURE_GZIP_DECOMPRESS /* gunzip_main may not be visible... */
if (opt & 0x18) // -d and/or -t
return gunzip_main(argc, argv);
#endif
#ifdef ENABLE_FEATURE_GZIP_LEVELS
opt >>= ENABLE_FEATURE_GZIP_DECOMPRESS ? 7 : 5; /* drop cfv[dt]qn bits */
if (opt == 0)
opt = 1 << 6; /* default: 6 */
opt = ffs(opt >> 4); /* Maps -1..-4 to [0], -5 to [1] ... -9 to [5] */
max_chain_length = 1 << gzip_level_config[opt].chain_shift;
good_match = gzip_level_config[opt].good;
max_lazy_match = gzip_level_config[opt].lazy2 * 2;
nice_match = gzip_level_config[opt].nice2 * 2;
#endif
option_mask32 &= 0x7; /* retain only -cfv */
/* Allocate all global buffers (for DYN_ALLOC option) */
ALLOC(uch, G1.l_buf, INBUFSIZ);
ALLOC(uch, G1.outbuf, OUTBUFSIZ);
ALLOC(ush, G1.d_buf, DIST_BUFSIZE);
ALLOC(uch, G1.window, 2L * WSIZE);
ALLOC(ush, G1.prev, 1L << BITS);
/* Initialize the CRC32 table */
global_crc32_table = crc32_filltable(NULL, 0);
argv += optind;
return bbunpack(argv, pack_gzip, append_ext, "gz");
}
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