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gerrit-public.fairphone.software / fp2-dev / platform / external / busybox / fa1c5aac51c5e4f880f72ffc66d409d61706ad8a / . / gzip.c
blob: 54bb727455d2252dbd440f0449128a4e1da3f1e9 [file] [log] [blame]
/* 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@lineo.com>, <andersee@debian.org>
* to support files as well as stdin/stdout, and to generally behave itself wrt
* command line handling.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/
/* These defines are very important for BusyBox. Without these,
* huge chunks of ram are pre-allocated making the BusyBox bss
* size Freaking Huge(tm), which is a bad thing.*/
#define SMALL_MEM
#define DYN_ALLOC
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <sys/types.h>
#include <signal.h>
#include <utime.h>
#include <ctype.h>
#include <sys/types.h>
#include <unistd.h>
#include <dirent.h>
#include <fcntl.h>
#include <time.h>
#include "busybox.h"
#define memzero(s, n) memset ((void *)(s), 0, (n))
#ifndef RETSIGTYPE
# define RETSIGTYPE void
#endif
typedef unsigned char uch;
typedef unsigned short ush;
typedef unsigned long ulg;
/* Return codes from gzip */
#define OK 0
#define ERROR 1
#define WARNING 2
/* Compression methods (see algorithm.doc) */
/* Only STORED and DEFLATED are supported by this BusyBox module */
#define STORED 0
/* methods 4 to 7 reserved */
#define DEFLATED 8
static int method; /* compression method */
/* To save memory for 16 bit systems, some arrays are overlaid between
* the various modules:
* deflate: prev+head window d_buf l_buf outbuf
* unlzw: tab_prefix tab_suffix stack inbuf outbuf
* For compression, input is done in window[]. For decompression, output
* is done in window except for unlzw.
*/
#ifndef INBUFSIZ
# ifdef SMALL_MEM
# define INBUFSIZ 0x2000 /* input buffer size */
# else
# define INBUFSIZ 0x8000 /* input buffer size */
# endif
#endif
#define INBUF_EXTRA 64 /* required by unlzw() */
#ifndef OUTBUFSIZ
# ifdef SMALL_MEM
# define OUTBUFSIZ 8192 /* output buffer size */
# else
# define OUTBUFSIZ 16384 /* output buffer size */
# endif
#endif
#define OUTBUF_EXTRA 2048 /* required by unlzw() */
#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
#ifdef DYN_ALLOC
# define DECLARE(type, array, size) static type * array
# define ALLOC(type, array, size) { \
array = (type*)calloc((size_t)(((size)+1L)/2), 2*sizeof(type)); \
if (array == NULL) error_msg(memory_exhausted); \
}
# define FREE(array) {if (array != NULL) free(array), array=NULL;}
#else
# define DECLARE(type, array, size) static type array[size]
# define ALLOC(type, array, size)
# define FREE(array)
#endif
#define tab_suffix window
#define tab_prefix prev /* hash link (see deflate.c) */
#define head (prev+WSIZE) /* hash head (see deflate.c) */
static long bytes_in; /* number of input bytes */
#define isize bytes_in
/* for compatibility with old zip sources (to be cleaned) */
typedef int file_t; /* Do not use stdio */
#define NO_FILE (-1) /* in memory compression */
#define PACK_MAGIC "\037\036" /* Magic header for packed files */
#define GZIP_MAGIC "\037\213" /* Magic header for gzip files, 1F 8B */
#define OLD_GZIP_MAGIC "\037\236" /* Magic header for gzip 0.5 = freeze 1.x */
#define LZH_MAGIC "\037\240" /* Magic header for SCO LZH Compress files */
#define PKZIP_MAGIC "\120\113\003\004" /* Magic header for pkzip files */
/* 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.
*/
/* put_byte is used for the compressed output */
#define put_byte(c) {outbuf[outcnt++]=(uch)(c); if (outcnt==OUTBUFSIZ)\
flush_outbuf();}
/* Output a 16 bit value, lsb first */
#define put_short(w) \
{ if (outcnt < OUTBUFSIZ-2) { \
outbuf[outcnt++] = (uch) ((w) & 0xff); \
outbuf[outcnt++] = (uch) ((ush)(w) >> 8); \
} else { \
put_byte((uch)((w) & 0xff)); \
put_byte((uch)((ush)(w) >> 8)); \
} \
}
/* Output a 32 bit value to the bit stream, lsb first */
#define put_long(n) { \
put_short((n) & 0xffff); \
put_short(((ulg)(n)) >> 16); \
}
#define seekable() 0 /* force sequential output */
#define translate_eol 0 /* no option -a yet */
/* Diagnostic functions */
#ifdef DEBUG
# define Assert(cond,msg) {if(!(cond)) 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
#define WARN(msg) {if (!quiet) fprintf msg ; \
if (exit_code == OK) exit_code = WARNING;}
#ifndef MAX_PATH_LEN
# define MAX_PATH_LEN 1024 /* max pathname length */
#endif
/* from zip.c: */
static int zip (int in, int out);
static int file_read (char *buf, unsigned size);
/* from gzip.c */
static RETSIGTYPE abort_gzip (void);
/* from deflate.c */
static void lm_init (ush * flags);
static ulg deflate (void);
/* from trees.c */
static void ct_init (ush * attr, int *methodp);
static int ct_tally (int dist, int lc);
static ulg flush_block (char *buf, ulg stored_len, int eof);
/* from bits.c */
static void bi_init (file_t zipfile);
static void send_bits (int value, int length);
static unsigned bi_reverse (unsigned value, int length);
static void bi_windup (void);
static void copy_block (char *buf, unsigned len, int header);
static int (*read_buf) (char *buf, unsigned size);
/* from util.c: */
static void flush_outbuf (void);
/* lzw.h -- define the lzw functions.
* 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.
*/
#if !defined(OF) && defined(lint)
# include "gzip.h"
#endif
#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".
*/
/* tailor.h -- target dependent definitions
* 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.
*/
/* The target dependent definitions should be defined here only.
* The target dependent functions should be defined in tailor.c.
*/
/* Common defaults */
#ifndef OS_CODE
# define OS_CODE 0x03 /* assume Unix */
#endif
#ifndef PATH_SEP
# define PATH_SEP '/'
#endif
#ifndef OPTIONS_VAR
# define OPTIONS_VAR "GZIP"
#endif
#ifndef Z_SUFFIX
# define Z_SUFFIX ".gz"
#endif
#ifdef MAX_EXT_CHARS
# define MAX_SUFFIX MAX_EXT_CHARS
#else
# define MAX_SUFFIX 30
#endif
/* global buffers */
DECLARE(uch, inbuf, INBUFSIZ + INBUF_EXTRA);
DECLARE(uch, outbuf, OUTBUFSIZ + OUTBUF_EXTRA);
DECLARE(ush, d_buf, DIST_BUFSIZE);
DECLARE(uch, window, 2L * WSIZE);
DECLARE(ush, tab_prefix, 1L << BITS);
static int crc_table_empty = 1;
static int foreground; /* set if program run in foreground */
static int method = DEFLATED; /* compression method */
static int exit_code = OK; /* program exit code */
static int part_nb; /* number of parts in .gz file */
static long time_stamp; /* original time stamp (modification time) */
static long ifile_size; /* input file size, -1 for devices (debug only) */
static char z_suffix[MAX_SUFFIX + 1]; /* default suffix (can be set with --suffix) */
static int z_len; /* strlen(z_suffix) */
static char ifname[MAX_PATH_LEN]; /* input file name */
static char ofname[MAX_PATH_LEN]; /* output file name */
static int ifd; /* input file descriptor */
static int ofd; /* output file descriptor */
static unsigned insize; /* valid bytes in inbuf */
static unsigned outcnt; /* bytes in output buffer */
/* ========================================================================
* Signal and error handler.
*/
static void abort_gzip()
{
exit(ERROR);
}
/* ===========================================================================
* Clear input and output buffers
*/
static void clear_bufs(void)
{
outcnt = 0;
insize = 0;
bytes_in = 0L;
}
static void write_error_msg()
{
fprintf(stderr, "\n");
perror("");
abort_gzip();
}
/* ===========================================================================
* Does the same as write(), but also handles partial pipe writes and checks
* for error return.
*/
static void write_buf(int fd, void *buf, unsigned cnt)
{
unsigned n;
while ((n = write(fd, buf, cnt)) != cnt) {
if (n == (unsigned) (-1)) {
write_error_msg();
}
cnt -= n;
buf = (void *) ((char *) buf + n);
}
}
/* ===========================================================================
* 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 ulg updcrc(uch *s, unsigned n)
{
static ulg crc = (ulg) 0xffffffffL; /* shift register contents */
register ulg c; /* temporary variable */
static unsigned long crc_32_tab[256];
if (crc_table_empty) {
unsigned long csr; /* crc shift register */
unsigned long e=0; /* polynomial exclusive-or pattern */
int i; /* counter for all possible eight bit values */
int k; /* byte being shifted into crc apparatus */
/* terms of polynomial defining this crc (except x^32): */
static const int p[] = {0,1,2,4,5,7,8,10,11,12,16,22,23,26};
/* Make exclusive-or pattern from polynomial (0xedb88320) */
for (i = 0; i < sizeof(p)/sizeof(int); i++)
e |= 1L << (31 - p[i]);
/* Compute and print table of CRC's, five per line */
crc_32_tab[0] = 0x00000000L;
for (i = 1; i < 256; i++) {
csr = i;
/* The idea to initialize the register with the byte instead of
* zero was stolen from Haruhiko Okumura's ar002
*/
for (k = 8; k; k--)
csr = csr & 1 ? (csr >> 1) ^ e : csr >> 1;
crc_32_tab[i]=csr;
}
}
if (s == NULL) {
c = 0xffffffffL;
} else {
c = crc;
if (n)
do {
c = crc_32_tab[((int) c ^ (*s++)) & 0xff] ^ (c >> 8);
} while (--n);
}
crc = c;
return c ^ 0xffffffffL; /* (instead of ~c for 64-bit machines) */
}
/* bits.c -- output variable-length bit strings
* 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
*
* Output variable-length bit strings. Compression can be done
* to a file or to memory. (The latter is not supported in this version.)
*
* DISCUSSION
*
* The PKZIP "deflate" file format interprets compressed file data
* as a sequence of bits. Multi-bit strings in the file may cross
* byte boundaries without restriction.
*
* The first bit of each byte is the low-order bit.
*
* The routines in this file allow a variable-length bit value to
* be output right-to-left (useful for literal values). For
* left-to-right output (useful for code strings from the tree routines),
* the bits must have been reversed first with bi_reverse().
*
* For in-memory compression, the compressed bit stream goes directly
* into the requested output buffer. The input data is read in blocks
* by the mem_read() function. The buffer is limited to 64K on 16 bit
* machines.
*
* INTERFACE
*
* void bi_init (FILE *zipfile)
* Initialize the bit string routines.
*
* void send_bits (int value, int length)
* Write out a bit string, taking the source bits right to
* left.
*
* int bi_reverse (int value, int length)
* Reverse the bits of a bit string, taking the source bits left to
* right and emitting them right to left.
*
* void bi_windup (void)
* Write out any remaining bits in an incomplete byte.
*
* void copy_block(char *buf, unsigned len, int header)
* Copy a stored block to the zip file, storing first the length and
* its one's complement if requested.
*
*/
/* ===========================================================================
* Local data used by the "bit string" routines.
*/
static file_t zfile; /* output gzip file */
static unsigned short bi_buf;
/* Output buffer. bits are inserted starting at the bottom (least significant
* bits).
*/
#define Buf_size (8 * 2*sizeof(char))
/* Number of bits used within bi_buf. (bi_buf might be implemented on
* more than 16 bits on some systems.)
*/
static 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
/* ===========================================================================
* Initialize the bit string routines.
*/
static void bi_init(file_t zipfile)
{
zfile = zipfile;
bi_buf = 0;
bi_valid = 0;
#ifdef DEBUG
bits_sent = 0L;
#endif
/* Set the defaults for file compression. They are set by memcompress
* for in-memory compression.
*/
if (zfile != NO_FILE) {
read_buf = file_read;
}
}
/* ===========================================================================
* 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");
bits_sent += (ulg) 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 (bi_valid > (int) Buf_size - length) {
bi_buf |= (value << bi_valid);
put_short(bi_buf);
bi_buf = (ush) value >> (Buf_size - bi_valid);
bi_valid += length - Buf_size;
} else {
bi_buf |= value << bi_valid;
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)
{
register unsigned res = 0;
do {
res |= code & 1;
code >>= 1, res <<= 1;
} while (--len > 0);
return res >> 1;
}
/* ===========================================================================
* Write out any remaining bits in an incomplete byte.
*/
static void bi_windup()
{
if (bi_valid > 8) {
put_short(bi_buf);
} else if (bi_valid > 0) {
put_byte(bi_buf);
}
bi_buf = 0;
bi_valid = 0;
#ifdef DEBUG
bits_sent = (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_short((ush) len);
put_short((ush) ~ len);
#ifdef DEBUG
bits_sent += 2 * 16;
#endif
}
#ifdef DEBUG
bits_sent += (ulg) len << 3;
#endif
while (len--) {
put_byte(*buf++);
}
}
/* deflate.c -- compress data using the deflation algorithm
* 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
*
* Identify new text as repetitions of old text within a fixed-
* length sliding window trailing behind the new text.
*
* DISCUSSION
*
* The "deflation" process depends on being able to identify portions
* of the input text which are identical to earlier input (within a
* sliding window trailing behind the input currently being processed).
*
* The most straightforward technique turns out to be the fastest for
* most input files: try all possible matches and select the longest.
* The key feature of this algorithm is that insertions into the string
* dictionary are very simple and thus fast, and deletions are avoided
* completely. Insertions are performed at each input character, whereas
* string matches are performed only when the previous match ends. So it
* is preferable to spend more time in matches to allow very fast string
* insertions and avoid deletions. The matching algorithm for small
* strings is inspired from that of Rabin & Karp. A brute force approach
* is used to find longer strings when a small match has been found.
* A similar algorithm is used in comic (by Jan-Mark Wams) and freeze
* (by Leonid Broukhis).
* A previous version of this file used a more sophisticated algorithm
* (by Fiala and Greene) which is guaranteed to run in linear amortized
* time, but has a larger average cost, uses more memory and is patented.
* However the F&G algorithm may be faster for some highly redundant
* files if the parameter max_chain_length (described below) is too large.
*
* ACKNOWLEDGEMENTS
*
* The idea of lazy evaluation of matches is due to Jan-Mark Wams, and
* I found it in 'freeze' written by Leonid Broukhis.
* Thanks to many info-zippers for bug reports and testing.
*
* REFERENCES
*
* APPNOTE.TXT documentation file in PKZIP 1.93a distribution.
*
* A description of the Rabin and Karp algorithm is given in the book
* "Algorithms" by R. Sedgewick, Addison-Wesley, p252.
*
* Fiala,E.R., and Greene,D.H.
* Data Compression with Finite Windows, Comm.ACM, 32,4 (1989) 490-595
*
* INTERFACE
*
* void lm_init (int pack_level, ush *flags)
* Initialize the "longest match" routines for a new file
*
* ulg deflate (void)
* Processes a new input file and return its compressed length. Sets
* the compressed length, crc, deflate flags and internal file
* attributes.
*/
/* ===========================================================================
* Configuration parameters
*/
/* 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
/* To save space (see unlzw.c), we overlay prev+head with tab_prefix and
* window with tab_suffix. Check that we can do this:
*/
#if (WSIZE<<1) > (1<<BITS)
# error cannot overlay window with tab_suffix and prev with tab_prefix0
#endif
#if HASH_BITS > BITS-1
# error cannot overlay head with tab_prefix1
#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 */
#define NIL 0
/* Tail of hash chains */
#define FAST 4
#define SLOW 2
/* speed options for the general purpose bit flag */
#ifndef TOO_FAR
# define TOO_FAR 4096
#endif
/* Matches of length 3 are discarded if their distance exceeds TOO_FAR */
/* ===========================================================================
* Local data used by the "longest match" routines.
*/
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.
*/
/* DECLARE(uch, window, 2L*WSIZE); */
/* 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(Pos, prev, 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, head, 1<<HASH_BITS); */
/* Heads of the hash chains or NIL. */
static const ulg window_size = (ulg) 2 * WSIZE;
/* window size, 2*WSIZE except for MMAP or BIG_MEM, where it is the
* input file length plus MIN_LOOKAHEAD.
*/
static long block_start;
/* window position at the beginning of the current output block. Gets
* negative when the window is moved backwards.
*/
static 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
*/
static unsigned int 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.
*/
static unsigned strstart; /* start of string to insert */
static unsigned match_start; /* start of matching string */
static int eofile; /* flag set at end of input file */
static unsigned lookahead; /* number of valid bytes ahead in window */
static const unsigned 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.
*/
static const unsigned int 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.
*/
#define 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.
*/
static const unsigned 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.
*/
static const int 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.
*/
#define EQUAL 0
/* result of memcmp for equal strings */
/* ===========================================================================
* Prototypes for local functions.
*/
static void fill_window (void);
static int longest_match (IPos cur_match);
#ifdef DEBUG
static void check_match (IPos start, IPos match, int length);
#endif
/* ===========================================================================
* Update a hash value with the given input byte
* IN assertion: all calls to 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)
/* ===========================================================================
* 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 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) \
(UPDATE_HASH(ins_h, window[(s) + MIN_MATCH-1]), \
prev[(s) & WMASK] = match_head = head[ins_h], \
head[ins_h] = (s))
/* ===========================================================================
* Initialize the "longest match" routines for a new file
*/
static void lm_init(ush *flags)
{
register unsigned j;
/* Initialize the hash table. */
memzero((char *) head, HASH_SIZE * sizeof(*head));
/* prev will be initialized on the fly */
*flags |= SLOW;
/* ??? reduce max_chain_length for binary files */
strstart = 0;
block_start = 0L;
lookahead = read_buf((char *) window,
sizeof(int) <= 2 ? (unsigned) WSIZE : 2 * WSIZE);
if (lookahead == 0 || lookahead == (unsigned) EOF) {
eofile = 1, lookahead = 0;
return;
}
eofile = 0;
/* Make sure that we always have enough lookahead. This is important
* if input comes from a device such as a tty.
*/
while (lookahead < MIN_LOOKAHEAD && !eofile)
fill_window();
ins_h = 0;
for (j = 0; j < MIN_MATCH - 1; j++)
UPDATE_HASH(ins_h, window[j]);
/* If lookahead < MIN_MATCH, ins_h is garbage, but this is
* not important since only literal bytes will be emitted.
*/
}
/* ===========================================================================
* 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 */
register uch *scan = window + strstart; /* current string */
register uch *match; /* matched string */
register int len; /* length of current match */
int best_len = prev_length; /* best match length so far */
IPos limit =
strstart > (IPos) MAX_DIST ? strstart - (IPos) MAX_DIST : NIL;
/* 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
register uch *strend = window + strstart + MAX_MATCH;
register uch scan_end1 = scan[best_len - 1];
register uch scan_end = scan[best_len];
/* Do not waste too much time if we already have a good match: */
if (prev_length >= good_match) {
chain_length >>= 2;
}
Assert(strstart <= window_size - MIN_LOOKAHEAD,
"insufficient lookahead");
do {
Assert(cur_match < strstart, "no future");
match = 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) {
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 = 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((char *) window + match,
(char *) window + start, length) != EQUAL) {
fprintf(stderr,
" start %d, match %d, length %d\n", start, match, length);
error_msg("invalid match");
}
if (verbose > 1) {
fprintf(stderr, "\\[%d,%d]", start - match, length);
do {
putc(window[start++], stderr);
} while (--length != 0);
}
}
#else
# define check_match(start, match, length)
#endif
/* ===========================================================================
* 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()
{
register unsigned n, m;
unsigned more =
(unsigned) (window_size - (ulg) lookahead - (ulg) 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) EOF) {
/* Very unlikely, but possible on 16 bit machine if strstart == 0
* and lookahead == 1 (input done one byte at time)
*/
more--;
} else if (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 == (ulg) 2 * WSIZE, "no sliding with BIG_MEM");
memcpy((char *) window, (char *) window + WSIZE, (unsigned) WSIZE);
match_start -= WSIZE;
strstart -= WSIZE; /* we now have strstart >= MAX_DIST: */
block_start -= (long) WSIZE;
for (n = 0; n < HASH_SIZE; n++) {
m = head[n];
head[n] = (Pos) (m >= WSIZE ? m - WSIZE : NIL);
}
for (n = 0; n < WSIZE; n++) {
m = prev[n];
prev[n] = (Pos) (m >= WSIZE ? m - WSIZE : NIL);
/* 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 (!eofile) {
n = read_buf((char *) window + strstart + lookahead, more);
if (n == 0 || n == (unsigned) EOF) {
eofile = 1;
} else {
lookahead += n;
}
}
}
/* ===========================================================================
* 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(block_start >= 0L ? (char*)&window[(unsigned)block_start] : \
(char*)NULL, (long)strstart - block_start, (eof))
/* ===========================================================================
* 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.
*/
static ulg deflate()
{
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 */
register unsigned match_length = MIN_MATCH - 1; /* length of best match */
/* Process the input block. */
while (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(strstart, hash_head);
/* Find the longest match, discarding those <= prev_length.
*/
prev_length = match_length, prev_match = match_start;
match_length = MIN_MATCH - 1;
if (hash_head != NIL && prev_length < max_lazy_match &&
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 > lookahead)
match_length = lookahead;
/* Ignore a length 3 match if it is too distant: */
if (match_length == MIN_MATCH
&& strstart - match_start > TOO_FAR) {
/* If prev_match is also MIN_MATCH, 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 (prev_length >= MIN_MATCH && match_length <= prev_length) {
check_match(strstart - 1, prev_match, prev_length);
flush =
ct_tally(strstart - 1 - prev_match,
prev_length - MIN_MATCH);
/* Insert in hash table all strings up to the end of the match.
* strstart-1 and strstart are already inserted.
*/
lookahead -= prev_length - 1;
prev_length -= 2;
do {
strstart++;
INSERT_STRING(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 (--prev_length != 0);
match_available = 0;
match_length = MIN_MATCH - 1;
strstart++;
if (flush)
FLUSH_BLOCK(0), block_start = 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", window[strstart - 1]));
if (ct_tally(0, window[strstart - 1])) {
FLUSH_BLOCK(0), block_start = strstart;
}
strstart++;
lookahead--;
} else {
/* There is no previous match to compare with, wait for
* the next step to decide.
*/
match_available = 1;
strstart++;
lookahead--;
}
Assert(strstart <= isize && lookahead <= 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 (lookahead < MIN_LOOKAHEAD && !eofile)
fill_window();
}
if (match_available)
ct_tally(0, window[strstart - 1]);
return FLUSH_BLOCK(1); /* eof */
}
/* gzip (GNU zip) -- compress files with zip algorithm and 'compress' interface
* Copyright (C) 1992-1993 Jean-loup Gailly
* The unzip code was written and put in the public domain by Mark Adler.
* Portions of the lzw code are derived from the public domain 'compress'
* written by Spencer Thomas, Joe Orost, James Woods, Jim McKie, Steve Davies,
* Ken Turkowski, Dave Mack and Peter Jannesen.
*
* See the license_msg below and the file COPYING for the software license.
* See the file algorithm.doc for the compression algorithms and file formats.
*/
/* Compress files with zip algorithm and 'compress' interface.
* See usage() and help() functions below for all options.
* Outputs:
* file.gz: compressed file with same mode, owner, and utimes
* or stdout with -c option or if stdin used as input.
* If the output file name had to be truncated, the original name is kept
* in the compressed file.
*/
/* configuration */
typedef struct dirent dir_type;
typedef RETSIGTYPE(*sig_type) (int);
/* ======================================================================== */
// int main (argc, argv)
// int argc;
// char **argv;
int gzip_main(int argc, char **argv)
{
int result;
int inFileNum;
int outFileNum;
struct stat statBuf;
char *delFileName;
int tostdout = 0;
int fromstdin = 0;
int force = 0;
int opt;
while ((opt = getopt(argc, argv, "cf123456789dq")) != -1) {
switch (opt) {
case 'c':
tostdout = 1;
break;
case 'f':
force = 1;
break;
/* Ignore 1-9 (compression level) options */
case '1': case '2': case '3': case '4': case '5':
case '6': case '7': case '8': case '9':
break;
case 'q':
break;
#ifdef BB_GUNZIP
case 'd':
optind = 1;
return gunzip_main(argc, argv);
#endif
default:
show_usage();
}
}
if ((optind == argc) || (strcmp(argv[optind], "-") == 0)) {
fromstdin = 1;
tostdout = 1;
}
if (isatty(fileno(stdout)) && tostdout==1 && force==0)
error_msg_and_die( "compressed data not written to terminal. Use -f to force it.");
foreground = signal(SIGINT, SIG_IGN) != SIG_IGN;
if (foreground) {
(void) signal(SIGINT, (sig_type) abort_gzip);
}
#ifdef SIGTERM
if (signal(SIGTERM, SIG_IGN) != SIG_IGN) {
(void) signal(SIGTERM, (sig_type) abort_gzip);
}
#endif
#ifdef SIGHUP
if (signal(SIGHUP, SIG_IGN) != SIG_IGN) {
(void) signal(SIGHUP, (sig_type) abort_gzip);
}
#endif
strncpy(z_suffix, Z_SUFFIX, sizeof(z_suffix) - 1);
z_len = strlen(z_suffix);
/* Allocate all global buffers (for DYN_ALLOC option) */
ALLOC(uch, inbuf, INBUFSIZ + INBUF_EXTRA);
ALLOC(uch, outbuf, OUTBUFSIZ + OUTBUF_EXTRA);
ALLOC(ush, d_buf, DIST_BUFSIZE);
ALLOC(uch, window, 2L * WSIZE);
ALLOC(ush, tab_prefix, 1L << BITS);
if (fromstdin == 1) {
strcpy(ofname, "stdin");
inFileNum = fileno(stdin);
time_stamp = 0; /* time unknown by default */
ifile_size = -1L; /* convention for unknown size */
} else {
/* Open up the input file */
strncpy(ifname, argv[optind], MAX_PATH_LEN);
/* Open input file */
inFileNum = open(ifname, O_RDONLY);
if (inFileNum < 0)
perror_msg_and_die("%s", ifname);
/* Get the time stamp on the input file. */
if (stat(ifname, &statBuf) < 0)
perror_msg_and_die("%s", ifname);
time_stamp = statBuf.st_ctime;
ifile_size = statBuf.st_size;
}
if (tostdout == 1) {
/* And get to work */
strcpy(ofname, "stdout");
outFileNum = fileno(stdout);
clear_bufs(); /* clear input and output buffers */
part_nb = 0;
/* Actually do the compression/decompression. */
zip(inFileNum, outFileNum);
} else {
/* And get to work */
strncpy(ofname, ifname, MAX_PATH_LEN - 4);
strcat(ofname, ".gz");
/* Open output fille */
#if (__GLIBC__ >= 2) && (__GLIBC_MINOR__ >= 1)
outFileNum = open(ofname, O_RDWR | O_CREAT | O_EXCL | O_NOFOLLOW);
#else
outFileNum = open(ofname, O_RDWR | O_CREAT | O_EXCL);
#endif
if (outFileNum < 0)
perror_msg_and_die("%s", ofname);
/* Set permissions on the file */
fchmod(outFileNum, statBuf.st_mode);
clear_bufs(); /* clear input and output buffers */
part_nb = 0;
/* Actually do the compression/decompression. */
result = zip(inFileNum, outFileNum);
close(outFileNum);
close(inFileNum);
/* Delete the original file */
if (result == OK)
delFileName = ifname;
else
delFileName = ofname;
if (unlink(delFileName) < 0)
perror_msg_and_die("%s", delFileName);
}
return(exit_code);
}
/* 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 (ush *attr, int *methodp)
* Allocate the match buffer, initialize the various tables and save
* the location of the internal file attribute (ascii/binary) and
* method (DEFLATE/STORE)
*
* void ct_tally (int dist, int lc);
* Save the match info and tally the frequency counts.
*
* long 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.
*
*/
/* ===========================================================================
* Constants
*/
#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 */
static const int extra_lbits[LENGTH_CODES] /* extra bits for each length code */
= { 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 };
static const int extra_dbits[D_CODES] /* extra bits for each distance code */
= { 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 };
static const int extra_blbits[BL_CODES] /* extra bits for each bit length code */
= { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 3, 7 };
#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.
*/
#if LIT_BUFSIZE > INBUFSIZ
error cannot overlay l_buf and inbuf
#endif
#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) *//* ===========================================================================
* Local data
*//* 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 */
static ct_data dyn_ltree[HEAP_SIZE]; /* literal and length tree */
static ct_data dyn_dtree[2 * D_CODES + 1]; /* distance tree */
static 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).
*/
static ct_data static_dtree[D_CODES];
/* The static distance tree. (Actually a trivial tree since all codes use
* 5 bits.)
*/
static ct_data bl_tree[2 * BL_CODES + 1];
/* Huffman tree for the bit lengths */
typedef struct tree_desc {
ct_data *dyn_tree; /* the dynamic tree */
ct_data *static_tree; /* corresponding static tree or NULL */
const int *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;
static tree_desc l_desc =
{ dyn_ltree, static_ltree, extra_lbits, LITERALS + 1, L_CODES,
MAX_BITS, 0 };
static tree_desc d_desc =
{ dyn_dtree, static_dtree, extra_dbits, 0, D_CODES, MAX_BITS, 0 };
static tree_desc bl_desc =
{ bl_tree, (ct_data *) 0, extra_blbits, 0, BL_CODES, MAX_BL_BITS,
0 };
static ush bl_count[MAX_BITS + 1];
/* number of codes at each bit length for an optimal tree */
static const uch bl_order[BL_CODES]
= { 16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15 };
/* The lengths of the bit length codes are sent in order of decreasing
* probability, to avoid transmitting the lengths for unused bit length codes.
*/
static int heap[2 * L_CODES + 1]; /* heap used to build the Huffman trees */
static int heap_len; /* number of elements in the heap */
static 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.
*/
static uch depth[2 * L_CODES + 1];
/* Depth of each subtree used as tie breaker for trees of equal frequency */
static uch length_code[MAX_MATCH - MIN_MATCH + 1];
/* length code for each normalized match length (0 == MIN_MATCH) */
static 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.
*/
static int base_length[LENGTH_CODES];
/* First normalized length for each code (0 = MIN_MATCH) */
static int base_dist[D_CODES];
/* First normalized distance for each code (0 = distance of 1) */
#define l_buf inbuf
/* DECLARE(uch, l_buf, LIT_BUFSIZE); buffer for literals or lengths */
/* DECLARE(ush, d_buf, DIST_BUFSIZE); buffer for distances */
static 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.
*/
static unsigned last_lit; /* running index in l_buf */
static unsigned last_dist; /* running index in d_buf */
static unsigned last_flags; /* running index in flag_buf */
static uch flags; /* current flags not yet saved in flag_buf */
static 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.
*/
static ulg opt_len; /* bit length of current block with optimal trees */
static ulg static_len; /* bit length of current block with static trees */
static ulg compressed_len; /* total bit length of compressed file */
static ush *file_type; /* pointer to UNKNOWN, BINARY or ASCII */
static int *file_method; /* pointer to DEFLATE or STORE */
/* ===========================================================================
* Local (static) routines in this file.
*/
static void init_block (void);
static void pqdownheap (ct_data * tree, int k);
static void gen_bitlen (tree_desc * desc);
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);
static void set_file_type (void);
#ifndef DEBUG
# define send_code(c, tree) send_bits(tree[c].Code, tree[c].Len)
/* Send a code of the given tree. c and tree must not have side effects */
#else /* DEBUG */
# define send_code(c, tree) \
{ if (verbose>1) fprintf(stderr,"\ncd %3d ",(c)); \
send_bits(tree[c].Code, tree[c].Len); }
#endif
#define d_code(dist) \
((dist) < 256 ? dist_code[dist] : 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 */
/* ===========================================================================
* Allocate the match buffer, initialize the various tables and save the
* location of the internal file attribute (ascii/binary) and method
* (DEFLATE/STORE).
*/
static void ct_init(ush *attr, int *methodp)
{
int n; /* iterates over tree elements */
int bits; /* bit counter */
int length; /* length value */
int code; /* code value */
int dist; /* distance index */
file_type = attr;
file_method = methodp;
compressed_len = 0L;
if (static_dtree[0].Len != 0)
return; /* ct_init already called */
/* Initialize the mapping length (0..255) -> length code (0..28) */
length = 0;
for (code = 0; code < LENGTH_CODES - 1; code++) {
base_length[code] = length;
for (n = 0; n < (1 << extra_lbits[code]); n++) {
length_code[length++] = (uch) 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:
*/
length_code[length - 1] = (uch) code;
/* Initialize the mapping dist (0..32K) -> dist code (0..29) */
dist = 0;
for (code = 0; code < 16; code++) {
base_dist[code] = dist;
for (n = 0; n < (1 << extra_dbits[code]); n++) {
dist_code[dist++] = (uch) code;
}
}
Assert(dist == 256, "ct_init: dist != 256");
dist >>= 7; /* from now on, all distances are divided by 128 */
for (; code < D_CODES; code++) {
base_dist[code] = dist << 7;
for (n = 0; n < (1 << (extra_dbits[code] - 7)); n++) {
dist_code[256 + dist++] = (uch) code;
}
}
Assert(dist == 256, "ct_init: 256+dist != 512");
/* Construct the codes of the static literal tree */
for (bits = 0; bits <= MAX_BITS; bits++)
bl_count[bits] = 0;
n = 0;
while (n <= 143)
static_ltree[n++].Len = 8, bl_count[8]++;
while (n <= 255)
static_ltree[n++].Len = 9, bl_count[9]++;
while (n <= 279)
static_ltree[n++].Len = 7, bl_count[7]++;
while (n <= 287)
static_ltree[n++].Len = 8, 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 *) static_ltree, L_CODES + 1);
/* The static distance tree is trivial: */
for (n = 0; n < D_CODES; n++) {
static_dtree[n].Len = 5;
static_dtree[n].Code = bi_reverse(n, 5);
}
/* Initialize the first block of the first file: */
init_block();
}
/* ===========================================================================
* Initialize a new block.
*/
static void init_block()
{
int n; /* iterates over tree elements */
/* Initialize the trees. */
for (n = 0; n < L_CODES; n++)
dyn_ltree[n].Freq = 0;
for (n = 0; n < D_CODES; n++)
dyn_dtree[n].Freq = 0;
for (n = 0; n < BL_CODES; n++)
bl_tree[n].Freq = 0;
dyn_ltree[END_BLOCK].Freq = 1;
opt_len = static_len = 0L;
last_lit = last_dist = last_flags = 0;
flags = 0;
flag_bit = 1;
}
#define SMALLEST 1
/* Index within the heap array of least frequent node in the Huffman tree */
/* ===========================================================================
* Remove the smallest element from the heap and recreate the heap with
* one less element. Updates heap and heap_len.
*/
#define pqremove(tree, top) \
{\
top = heap[SMALLEST]; \
heap[SMALLEST] = heap[heap_len--]; \
pqdownheap(tree, SMALLEST); \
}
/* ===========================================================================
* 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 && depth[n] <= depth[m]))
/* ===========================================================================
* 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).
*/
static void pqdownheap(ct_data *tree, int k)
{
int v = heap[k];
int j = k << 1; /* left son of k */
while (j <= heap_len) {
/* Set j to the smallest of the two sons: */
if (j < heap_len && smaller(tree, heap[j + 1], heap[j]))
j++;
/* Exit if v is smaller than both sons */
if (smaller(tree, v, heap[j]))
break;
/* Exchange v with the smallest son */
heap[k] = heap[j];
k = j;
/* And continue down the tree, setting j to the left son of k */
j <<= 1;
}
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 int *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++)
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[heap[heap_max]].Len = 0; /* root of the heap */
for (h = heap_max + 1; h < HEAP_SIZE; h++) {
n = 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 */
bl_count[bits]++;
xbits = 0;
if (n >= base)
xbits = extra[n - base];
f = tree[n].Freq;
opt_len += (ulg) f *(bits + xbits);
if (stree)
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 (bl_count[bits] == 0)
bits--;
bl_count[bits]--; /* move one leaf down the tree */
bl_count[bits + 1] += 2; /* move one overflow item as its brother */
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 = bl_count[bits];
while (n != 0) {
m = 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));
opt_len +=
((long) bits -
(long) tree[m].Len) * (long) tree[m].Freq;
tree[m].Len = (ush) 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 + bl_count[bits - 1]) << 1;
}
/* Check that the bit counts in bl_count are consistent. The last code
* must be all ones.
*/
Assert(code + 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 != static_ltree,
(stderr, "\nn %3d %c l %2d c %4x (%x) ", n,
(isgraph(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.
*/
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.
*/
heap_len = 0, heap_max = HEAP_SIZE;
for (n = 0; n < elems; n++) {
if (tree[n].Freq != 0) {
heap[++heap_len] = max_code = n;
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 (heap_len < 2) {
int new = heap[++heap_len] = (max_code < 2 ? ++max_code : 0);
tree[new].Freq = 1;
depth[new] = 0;
opt_len--;
if (stree)
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 = 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 = heap[SMALLEST]; /* m = node of next least frequency */
heap[--heap_max] = n; /* keep the nodes sorted by frequency */
heap[--heap_max] = m;
/* Create a new node father of n and m */
tree[node].Freq = tree[n].Freq + tree[m].Freq;
depth[node] = (uch) (MAX(depth[n], depth[m]) + 1);
tree[n].Dad = tree[m].Dad = (ush) node;
#ifdef DUMP_BL_TREE
if (tree == bl_tree) {
fprintf(stderr, "\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 */
heap[SMALLEST] = node++;
pqdownheap(tree, SMALLEST);
} while (heap_len >= 2);
heap[--heap_max] = 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 = (ush) 0xffff; /* guard */
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) {
bl_tree[curlen].Freq += count;
} else if (curlen != 0) {
if (curlen != prevlen)
bl_tree[curlen].Freq++;
bl_tree[REP_3_6].Freq++;
} else if (count <= 10) {
bl_tree[REPZ_3_10].Freq++;
} else {
bl_tree[REPZ_11_138].Freq++;
}
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;
}
}
}
/* ===========================================================================
* 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, bl_tree);
} while (--count != 0);
} else if (curlen != 0) {
if (curlen != prevlen) {
send_code(curlen, bl_tree);
count--;
}
Assert(count >= 3 && count <= 6, " 3_6?");
send_code(REP_3_6, bl_tree);
send_bits(count - 3, 2);
} else if (count <= 10) {
send_code(REPZ_3_10, bl_tree);
send_bits(count - 3, 3);
} else {
send_code(REPZ_11_138, 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 const int build_bl_tree()
{
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((ct_data *) dyn_ltree, l_desc.max_code);
scan_tree((ct_data *) dyn_dtree, d_desc.max_code);
/* Build the bit length tree: */
build_tree((tree_desc *) (&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 (bl_tree[bl_order[max_blindex]].Len != 0)
break;
}
/* Update opt_len to include the bit length tree and counts */
opt_len += 3 * (max_blindex + 1) + 5 + 5 + 4;
Tracev(
(stderr, "\ndyn trees: dyn %ld, stat %ld", opt_len,
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(bl_tree[bl_order[rank]].Len, 3);
}
Tracev((stderr, "\nbl tree: sent %ld", bits_sent));
send_tree((ct_data *) dyn_ltree, lcodes - 1); /* send the literal tree */
Tracev((stderr, "\nlit tree: sent %ld", bits_sent));
send_tree((ct_data *) dyn_dtree, dcodes - 1); /* send the distance tree */
Tracev((stderr, "\ndist tree: sent %ld", bits_sent));
}
/* ===========================================================================
* 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 */
flag_buf[last_flags] = flags; /* Save the flags for the last 8 items */
/* Check if the file is ascii or binary */
if (*file_type == (ush) UNKNOWN)
set_file_type();
/* Construct the literal and distance trees */
build_tree((tree_desc *) (&l_desc));
Tracev((stderr, "\nlit data: dyn %ld, stat %ld", opt_len, static_len));
build_tree((tree_desc *) (&d_desc));
Tracev(
(stderr, "\ndist data: dyn %ld, stat %ld", opt_len,
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 = (opt_len + 3 + 7) >> 3;
static_lenb = (static_len + 3 + 7) >> 3;
Trace(
(stderr,
"\nopt %lu(%lu) stat %lu(%lu) stored %lu lit %u dist %u ",
opt_lenb, opt_len, static_lenb, static_len, stored_len,
last_lit, 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 && compressed_len == 0L
&& seekable()) {
/* Since LIT_BUFSIZE <= 2*WSIZE, the input data must be there: */
if (buf == (char *) 0)
error_msg("block vanished");
copy_block(buf, (unsigned) stored_len, 0); /* without header */
compressed_len = stored_len << 3;
*file_method = STORED;
} else if (stored_len + 4 <= opt_lenb && buf != (char *) 0) {
/* 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 */
compressed_len = (compressed_len + 3 + 7) & ~7L;
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 *) static_ltree,
(ct_data *) static_dtree);
compressed_len += 3 + static_len;
} else {
send_bits((DYN_TREES << 1) + eof, 3);
send_all_trees(l_desc.max_code + 1, d_desc.max_code + 1,
max_blindex + 1);
compress_block((ct_data *) dyn_ltree,
(ct_data *) dyn_dtree);
compressed_len += 3 + opt_len;
}
Assert(compressed_len == bits_sent, "bad compressed size");
init_block();
if (eof) {
bi_windup();
compressed_len += 7; /* align on byte boundary */
}
Tracev((stderr, "\ncomprlen %lu(%lu) ", compressed_len >> 3,
compressed_len - 7 * eof));
return compressed_len >> 3;
}
/* ===========================================================================
* 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)
{
l_buf[last_lit++] = (uch) lc;
if (dist == 0) {
/* lc is the unmatched char */
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");
dyn_ltree[length_code[lc] + LITERALS + 1].Freq++;
dyn_dtree[d_code(dist)].Freq++;
d_buf[last_dist++] = (ush) dist;
flags |= flag_bit;
}
flag_bit <<= 1;
/* Output the flags if they fill a byte: */
if ((last_lit & 7) == 0) {
flag_buf[last_flags++] = flags;
flags = 0, flag_bit = 1;
}
/* Try to guess if it is profitable to stop the current block here */
if ((last_lit & 0xfff) == 0) {
/* Compute an upper bound for the compressed length */
ulg out_length = (ulg) last_lit * 8L;
ulg in_length = (ulg) strstart - block_start;
int dcode;
for (dcode = 0; dcode < D_CODES; dcode++) {
out_length +=
(ulg) dyn_dtree[dcode].Freq * (5L + extra_dbits[dcode]);
}
out_length >>= 3;
Trace(
(stderr,
"\nlast_lit %u, last_dist %u, in %ld, out ~%ld(%ld%%) ",
last_lit, last_dist, in_length, out_length,
100L - out_length * 100L / in_length));
if (last_dist < last_lit / 2 && out_length < in_length / 2)
return 1;
}
return (last_lit == LIT_BUFSIZE - 1 || 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 (last_lit != 0)
do {
if ((lx & 7) == 0)
flag = flag_buf[fx++];
lc = l_buf[lx++];
if ((flag & 1) == 0) {
send_code(lc, ltree); /* send a literal byte */
Tracecv(isgraph(lc), (stderr, " '%c' ", lc));
} else {
/* Here, lc is the match length - MIN_MATCH */
code = length_code[lc];
send_code(code + LITERALS + 1, ltree); /* send the length code */
extra = extra_lbits[code];
if (extra != 0) {
lc -= base_length[code];
send_bits(lc, extra); /* send the extra length bits */
}
dist = 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 -= base_dist[code];
send_bits(dist, extra); /* send the extra distance bits */
}
} /* literal or match pair ? */
flag >>= 1;
} while (lx < last_lit);
send_code(END_BLOCK, ltree);
}
/* ===========================================================================
* Set the file type to ASCII or BINARY, using a crude approximation:
* binary if more than 20% of the bytes are <= 6 or >= 128, ascii otherwise.
* IN assertion: the fields freq of dyn_ltree are set and the total of all
* frequencies does not exceed 64K (to fit in an int on 16 bit machines).
*/
static void set_file_type()
{
int n = 0;
unsigned ascii_freq = 0;
unsigned bin_freq = 0;
while (n < 7)
bin_freq += dyn_ltree[n++].Freq;
while (n < 128)
ascii_freq += dyn_ltree[n++].Freq;
while (n < LITERALS)
bin_freq += dyn_ltree[n++].Freq;
*file_type = bin_freq > (ascii_freq >> 2) ? BINARY : ASCII;
if (*file_type == BINARY && translate_eol) {
error_msg("-l used on binary file");
}
}
/* zip.c -- compress files to the gzip or pkzip format
* 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.
*/
static ulg crc; /* crc on uncompressed file data */
static long header_bytes; /* number of bytes in gzip header */
/* ===========================================================================
* Deflate in to out.
* IN assertions: the input and output buffers are cleared.
* The variables time_stamp and save_orig_name are initialized.
*/
static int zip(int in, int out)
{
uch my_flags = 0; /* general purpose bit flags */
ush attr = 0; /* ascii/binary flag */
ush deflate_flags = 0; /* pkzip -es, -en or -ex equivalent */
ifd = in;
ofd = out;
outcnt = 0;
/* Write the header to the gzip file. See algorithm.doc for the format */
method = DEFLATED;
put_byte(GZIP_MAGIC[0]); /* magic header */
put_byte(GZIP_MAGIC[1]);
put_byte(DEFLATED); /* compression method */
put_byte(my_flags); /* general flags */
put_long(time_stamp);
/* Write deflated file to zip file */
crc = updcrc(0, 0);
bi_init(out);
ct_init(&attr, &method);
lm_init(&deflate_flags);
put_byte((uch) deflate_flags); /* extra flags */
put_byte(OS_CODE); /* OS identifier */
header_bytes = (long) outcnt;
(void) deflate();
/* Write the crc and uncompressed size */
put_long(crc);
put_long(isize);
header_bytes += 2 * sizeof(long);
flush_outbuf();
return OK;
}
/* ===========================================================================
* 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 int file_read(char *buf, unsigned size)
{
unsigned len;
Assert(insize == 0, "inbuf not empty");
len = read(ifd, buf, size);
if (len == (unsigned) (-1) || len == 0)
return (int) len;
crc = updcrc((uch *) buf, len);
isize += (ulg) len;
return (int) len;
}
/* ===========================================================================
* Write the output buffer outbuf[0..outcnt-1] and update bytes_out.
* (used for the compressed data only)
*/
static void flush_outbuf()
{
if (outcnt == 0)
return;
write_buf(ofd, (char *) outbuf, outcnt);
outcnt = 0;
}