| /* 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*)xcalloc((size_t)(((size)+1L)/2), 2*sizeof(type)); \ |
| } |
| # 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 32 bit value to the bit stream, lsb first */ |
| #if 0 |
| #define put_long(n) { \ |
| put_short((n) & 0xffff); \ |
| put_short(((ulg)(n)) >> 16); \ |
| } |
| #endif |
| |
| #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 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 */ |
| |
| |
| /* Output a 16 bit value, lsb first */ |
| static void put_short(ush 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)); |
| } |
| } |
| |
| /* ======================================================================== |
| * 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(void) |
| { |
| 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 */ |
| const unsigned long e = 0xedb88320L; /* polynomial exclusive-or pattern */ |
| int i; /* counter for all possible eight bit values */ |
| int k; /* byte being shifted into crc apparatus */ |
| |
| /* Compute table of CRC's. */ |
| 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 gzip_main(int argc, char **argv) |
| { |
| int result; |
| int inFileNum; |
| int outFileNum; |
| struct stat statBuf; |
| char *delFileName; |
| int tostdout = 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 CONFIG_GUNZIP |
| case 'd': |
| optind = 1; |
| return gunzip_main(argc, argv); |
| #endif |
| default: |
| show_usage(); |
| } |
| } |
| |
| 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); |
| |
| clear_bufs(); |
| part_nb = 0; |
| |
| if (optind == argc) { |
| time_stamp = 0; |
| ifile_size = -1L; |
| zip(STDIN_FILENO, STDOUT_FILENO); |
| } else { |
| int i; |
| |
| for (i = optind; i < argc; i++) { |
| char *path = NULL; |
| |
| if (strcmp(argv[i], "-") == 0) { |
| time_stamp = 0; |
| ifile_size = -1L; |
| inFileNum = STDIN_FILENO; |
| outFileNum = STDOUT_FILENO; |
| } else { |
| inFileNum = open(argv[i], O_RDONLY); |
| if (inFileNum < 0 || fstat(inFileNum, &statBuf) < 0) |
| perror_msg_and_die("%s", argv[i]); |
| time_stamp = statBuf.st_ctime; |
| ifile_size = statBuf.st_size; |
| |
| if (!tostdout) { |
| path = xmalloc(strlen(argv[i]) + 4); |
| strcpy(path, argv[i]); |
| strcat(path, ".gz"); |
| |
| /* Open output file */ |
| #if (__GLIBC__ >= 2) && (__GLIBC_MINOR__ >= 1) |
| outFileNum = |
| open(path, O_RDWR | O_CREAT | O_EXCL | O_NOFOLLOW); |
| #else |
| outFileNum = open(path, O_RDWR | O_CREAT | O_EXCL); |
| #endif |
| if (outFileNum < 0) { |
| perror_msg("%s", path); |
| free(path); |
| continue; |
| } |
| |
| /* Set permissions on the file */ |
| fchmod(outFileNum, statBuf.st_mode); |
| } else |
| outFileNum = STDOUT_FILENO; |
| } |
| |
| if (path == NULL && isatty(outFileNum) && force == 0) { |
| error_msg |
| ("compressed data not written to a terminal. Use -f to force compression."); |
| free(path); |
| continue; |
| } |
| |
| result = zip(inFileNum, outFileNum); |
| |
| if (path != NULL) { |
| close(inFileNum); |
| close(outFileNum); |
| |
| /* Delete the original file */ |
| if (result == OK) |
| delFileName = argv[i]; |
| else |
| delFileName = path; |
| |
| if (unlink(delFileName) < 0) |
| perror_msg("%s", delFileName); |
| } |
| |
| free(path); |
| } |
| } |
| |
| 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 */ |
| |
| typedef uch extra_bits_t; |
| |
| /* extra bits for each length code */ |
| static const extra_bits_t extra_lbits[LENGTH_CODES] |
| = { 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 extra_bits_t extra_dbits[D_CODES] |
| = { 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 extra_bits_t extra_blbits[BL_CODES] |
| = { 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 extra_bits_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; |
| |
| 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 extra_bits_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++) |
| 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 */ |
| |
| static void put_long(ulg n) |
| { |
| put_short((n) & 0xffff); |
| put_short(((ulg) (n)) >> 16); |
| } |
| |
| /* put_header_byte is used for the compressed output |
| * - for the initial 4 bytes that can't overflow the buffer. |
| */ |
| #define put_header_byte(c) {outbuf[outcnt++]=(uch)(c);} |
| |
| /* =========================================================================== |
| * 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_header_byte(GZIP_MAGIC[0]); /* magic header */ |
| put_header_byte(GZIP_MAGIC[1]); |
| put_header_byte(DEFLATED); /* compression method */ |
| |
| put_header_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; |
| } |