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Diffstat (limited to 'archival/gzip.c')
-rw-r--r-- | archival/gzip.c | 2473 |
1 files changed, 2473 insertions, 0 deletions
diff --git a/archival/gzip.c b/archival/gzip.c new file mode 100644 index 000000000..c9b67538e --- /dev/null +++ b/archival/gzip.c @@ -0,0 +1,2473 @@ +/* vi: set sw=4 ts=4: */ +/* + * Gzip implementation for busybox + * + * Based on GNU gzip Copyright (C) 1992-1993 Jean-loup Gailly. + * + * Originally adjusted for busybox by Charles P. Wright <cpw@unix.asb.com> + * "this is a stripped down version of gzip I put into busybox, it does + * only standard in to standard out with -9 compression. It also requires + * the zcat module for some important functions." + * + * Adjusted further by Erik Andersen <andersen@codepoet.org> to support + * files as well as stdin/stdout, and to generally behave itself wrt + * command line handling. + * + * Licensed under GPLv2 or later, see file LICENSE in this tarball for details. + */ + +/* TODO: full support for -v for DESKTOP +/usr/bin/gzip -v a bogus aa +a: 85.1% -- replaced with a.gz +gzip: bogus: No such file or directory +aa: 85.1% -- replaced with aa.gz +*/ + +#define SMALL_MEM + +#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" + +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 + +/* 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 + +# define DECLARE(type, array, size) static type * array +# define ALLOC(type, array, size) { \ + array = (type*)xzalloc((size_t)(((size)+1L)/2) * 2*sizeof(type)); \ + } +# define FREE(array) {free(array), array=NULL;} + +#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();} + +#define seekable() 0 /* force sequential output */ +#define translate_eol 0 /* no option -a yet */ + +/* Diagnostic functions */ +#ifdef DEBUG +# define Assert(cond,msg) {if(!(cond)) bb_error_msg(msg);} +# define Trace(x) fprintf x +# define Tracev(x) {if (verbose) fprintf x ;} +# define Tracevv(x) {if (verbose>1) fprintf x ;} +# define Tracec(c,x) {if (verbose && (c)) fprintf x ;} +# define Tracecv(c,x) {if (verbose>1 && (c)) fprintf x ;} +#else +# define Assert(cond,msg) +# define Trace(x) +# define Tracev(x) +# define Tracevv(x) +# define Tracec(c,x) +# define Tracecv(c,x) +#endif + +#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 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. + */ + +#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 foreground; /* set if program run in foreground */ +static int method = DEFLATED; /* compression method */ +static int exit_code = OK; /* program exit code */ +static long time_stamp; /* original time stamp (modification time) */ +static char z_suffix[MAX_SUFFIX + 1]; /* default suffix (can be set with --suffix) */ + +static int ifd; /* input file descriptor */ +static int ofd; /* output file descriptor */ +#ifdef DEBUG +static unsigned insize; /* valid bytes in inbuf */ +#endif +static unsigned outcnt; /* bytes in output buffer */ + +static uint32_t *crc_32_tab; + +/* 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(int ATTRIBUTE_UNUSED ignored) +{ + exit(ERROR); +} + +/* =========================================================================== + * Clear input and output buffers + */ +static void clear_bufs(void) +{ + outcnt = 0; +#ifdef DEBUG + insize = 0; +#endif + bytes_in = 0L; +} + +/* =========================================================================== + * 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)) bb_error_msg_and_die(bb_msg_write_error); + 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 uint32_t updcrc(uch * s, unsigned n) +{ + static uint32_t crc = ~0; /* shift register contents */ + uint32_t c; /* temporary variable */ + + if (s == NULL) { + c = ~0; + } else { + c = crc; + if (n) + do { + c = crc_32_tab[((int) c ^ (*s++)) & 0xff] ^ (c >> 8); + } while (--n); + } + crc = c; + return ~c; +} + +/* 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) +{ + 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(void) +{ + 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. + * + * ACKNOWLEDGMENTS + * + * 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 */ + +enum { + max_chain_length = 4096, + +/* To speed up deflation, hash chains are never searched beyond this length. + * A higher limit improves compression ratio but degrades the speed. + */ + + max_lazy_match = 258, + +/* Attempt to find a better match only when the current match is strictly + * smaller than this value. This mechanism is used only for compression + * levels >= 4. + */ + max_insert_length = max_lazy_match, +/* Insert new strings in the hash table only if the match length + * is not greater than this length. This saves time but degrades compression. + * max_insert_length is used only for compression levels <= 3. + */ + + good_match = 32, + +/* Use a faster search when the previous match is longer than this */ + + +/* Values for max_lazy_match, good_match and max_chain_length, depending on + * the desired pack level (0..9). The values given below have been tuned to + * exclude worst case performance for pathological files. Better values may be + * found for specific files. + */ + + nice_match = 258 /* Stop searching when current match exceeds this */ + +/* Note: the deflate() code requires max_lazy >= MIN_MATCH and max_chain >= 4 + * For deflate_fast() (levels <= 3) good is ignored and lazy has a different + * meaning. + */ +}; + +#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) +{ + unsigned j; + + /* Initialize the hash table. */ + memset(head, 0, 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 */ + uch *scan = window + strstart; /* current string */ + uch *match; /* matched string */ + 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 + uch *strend = window + strstart + MAX_MATCH; + uch scan_end1 = scan[best_len - 1]; + uch scan_end = scan[best_len]; + + /* Do not waste too much time if we already have a good match: */ + if (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) { + bb_error_msg(" start %d, match %d, length %d", start, match, length); + bb_error_msg("invalid match"); + } + if (verbose > 1) { + bb_error_msg("\\[%d,%d]", start - match, length); + do { + 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(void) +{ + 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(void) +{ + IPos hash_head; /* head of hash chain */ + IPos prev_match; /* previous match */ + int flush; /* set if current block must be flushed */ + int match_available = 0; /* set if previous match exists */ + unsigned match_length = MIN_MATCH - 1; /* length of best match */ + + /* Process the input block. */ + while (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; + +/* ======================================================================== */ +int gzip_main(int argc, char **argv) +{ + enum { + OPT_tostdout = 0x1, + OPT_force = 0x2, + }; + + unsigned opt; + int result; + int inFileNum; + int outFileNum; + struct stat statBuf; + char *delFileName; + + opt = getopt32(argc, argv, "cf123456789qv" USE_GUNZIP("d")); + //if (opt & 0x1) // -c + //if (opt & 0x2) // -f + /* Ignore 1-9 (compression level) options */ + //if (opt & 0x4) // -1 + //if (opt & 0x8) // -2 + //if (opt & 0x10) // -3 + //if (opt & 0x20) // -4 + //if (opt & 0x40) // -5 + //if (opt & 0x80) // -6 + //if (opt & 0x100) // -7 + //if (opt & 0x200) // -8 + //if (opt & 0x400) // -9 + //if (opt & 0x800) // -q + //if (opt & 0x1000) // -v + if (ENABLE_GUNZIP && (opt & 0x2000)) { // -d + /* FIXME: getopt32 should not depend on optind */ + optind = 1; + return gunzip_main(argc, argv); + } + + foreground = signal(SIGINT, SIG_IGN) != SIG_IGN; + if (foreground) { + (void) signal(SIGINT, abort_gzip); + } +#ifdef SIGTERM + if (signal(SIGTERM, SIG_IGN) != SIG_IGN) { + (void) signal(SIGTERM, abort_gzip); + } +#endif +#ifdef SIGHUP + if (signal(SIGHUP, SIG_IGN) != SIG_IGN) { + (void) signal(SIGHUP, abort_gzip); + } +#endif + + strncpy(z_suffix, Z_SUFFIX, sizeof(z_suffix) - 1); + + /* 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); + + /* Initialise the CRC32 table */ + crc_32_tab = crc32_filltable(0); + + clear_bufs(); + + if (optind == argc) { + time_stamp = 0; + zip(STDIN_FILENO, STDOUT_FILENO); + } else { + int i; + + for (i = optind; i < argc; i++) { + char *path = NULL; + + clear_bufs(); + if (strcmp(argv[i], "-") == 0) { + time_stamp = 0; + inFileNum = STDIN_FILENO; + outFileNum = STDOUT_FILENO; + } else { + inFileNum = xopen(argv[i], O_RDONLY); + if (fstat(inFileNum, &statBuf) < 0) + bb_perror_msg_and_die("%s", argv[i]); + time_stamp = statBuf.st_ctime; + + if (!(opt & OPT_tostdout)) { + path = xasprintf("%s.gz", argv[i]); + + /* Open output file */ +#if (__GLIBC__ >= 2) && (__GLIBC_MINOR__ >= 1) && defined O_NOFOLLOW + 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) { + bb_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) && !(opt & OPT_force)) { + bb_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) + bb_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) bb_error_msg("\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(void) +{ + 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) { + bb_error_msg("\nnode %d(%d), sons %d(%d) %d(%d)", + node, tree[node].Freq, n, tree[n].Freq, m, tree[m].Freq); + } +#endif + /* and insert the new node in the heap */ + 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 int build_bl_tree(void) +{ + int max_blindex; /* index of last bit length code of non zero freq */ + + /* Determine the bit length frequencies for literal and distance trees */ + scan_tree((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) + bb_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(void) +{ + 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) { + bb_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 uint32_t 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(void) +{ + if (outcnt == 0) + return; + + write_buf(ofd, (char *) outbuf, outcnt); + outcnt = 0; +} |