| /* vi: set sw=4 ts=4: */ |
| /* |
| * Gzip implementation for busybox |
| * |
| * Based on GNU gzip Copyright (C) 1992-1993 Jean-loup Gailly. |
| * |
| * Originally adjusted for busybox by Charles P. Wright <cpw@unix.asb.com> |
| * "this is a stripped down version of gzip I put into busybox, it does |
| * only standard in to standard out with -9 compression. It also requires |
| * the zcat module for some important functions." |
| * |
| * Adjusted further by Erik Andersen <andersen@codepoet.org> to support |
| * files as well as stdin/stdout, and to generally behave itself wrt |
| * command line handling. |
| * |
| * Licensed under GPLv2 or later, see file LICENSE in this source tree. |
| */ |
| /* TODO: full support for -v for DESKTOP |
| * "/usr/bin/gzip -v a bogus aa" should say: |
| a: 85.1% -- replaced with a.gz |
| gzip: bogus: No such file or directory |
| aa: 85.1% -- replaced with aa.gz |
| */ |
| //config:config GZIP |
| //config: bool "gzip (19 kb)" |
| //config: default y |
| //config: help |
| //config: gzip is used to compress files. |
| //config: It's probably the most widely used UNIX compression program. |
| //config: |
| //config:config FEATURE_GZIP_LONG_OPTIONS |
| //config: bool "Enable long options" |
| //config: default y |
| //config: depends on GZIP && LONG_OPTS |
| //config: |
| //config:config GZIP_FAST |
| //config: int "Trade memory for speed (0:small,slow - 2:fast,big)" |
| //config: default 0 |
| //config: range 0 2 |
| //config: depends on GZIP |
| //config: help |
| //config: Enable big memory options for gzip. |
| //config: 0: small buffers, small hash-tables |
| //config: 1: larger buffers, larger hash-tables |
| //config: 2: larger buffers, largest hash-tables |
| //config: Larger models may give slightly better compression |
| //config: |
| //config:config FEATURE_GZIP_LEVELS |
| //config: bool "Enable compression levels" |
| //config: default n |
| //config: depends on GZIP |
| //config: help |
| //config: Enable support for compression levels 4-9. The default level |
| //config: is 6. If levels 1-3 are specified, 4 is used. |
| //config: If this option is not selected, -N options are ignored and -9 |
| //config: is used. |
| //config: |
| //config:config FEATURE_GZIP_DECOMPRESS |
| //config: bool "Enable decompression" |
| //config: default y |
| //config: depends on GZIP || GUNZIP || ZCAT |
| //config: help |
| //config: Enable -d (--decompress) and -t (--test) options for gzip. |
| //config: This will be automatically selected if gunzip or zcat is |
| //config: enabled. |
| |
| //applet:IF_GZIP(APPLET(gzip, BB_DIR_BIN, BB_SUID_DROP)) |
| |
| //kbuild:lib-$(CONFIG_GZIP) += gzip.o |
| |
| //usage:#define gzip_trivial_usage |
| //usage: "[-cfk" IF_FEATURE_GZIP_DECOMPRESS("dt") IF_FEATURE_GZIP_LEVELS("123456789") "] [FILE]..." |
| //usage:#define gzip_full_usage "\n\n" |
| //usage: "Compress FILEs (or stdin)\n" |
| //usage: IF_FEATURE_GZIP_LEVELS( |
| //usage: "\n -1..9 Compression level" |
| //usage: ) |
| //usage: IF_FEATURE_GZIP_DECOMPRESS( |
| //usage: "\n -d Decompress" |
| //usage: "\n -t Test file integrity" |
| //usage: ) |
| //usage: "\n -c Write to stdout" |
| //usage: "\n -f Force" |
| //usage: "\n -k Keep input files" |
| //usage: |
| //usage:#define gzip_example_usage |
| //usage: "$ ls -la /tmp/busybox*\n" |
| //usage: "-rw-rw-r-- 1 andersen andersen 1761280 Apr 14 17:47 /tmp/busybox.tar\n" |
| //usage: "$ gzip /tmp/busybox.tar\n" |
| //usage: "$ ls -la /tmp/busybox*\n" |
| //usage: "-rw-rw-r-- 1 andersen andersen 554058 Apr 14 17:49 /tmp/busybox.tar.gz\n" |
| |
| #include "libbb.h" |
| #include "bb_archive.h" |
| |
| /* =========================================================================== |
| */ |
| //#define DEBUG 1 |
| /* Diagnostic functions */ |
| #ifdef DEBUG |
| static int verbose; |
| # define Assert(cond,msg) { if (!(cond)) bb_error_msg(msg); } |
| # define Trace(x) fprintf x |
| # define Tracev(x) {if (verbose) fprintf x; } |
| # define Tracevv(x) {if (verbose > 1) fprintf x; } |
| # define Tracec(c,x) {if (verbose && (c)) fprintf x; } |
| # define Tracecv(c,x) {if (verbose > 1 && (c)) fprintf x; } |
| #else |
| # define Assert(cond,msg) |
| # define Trace(x) |
| # define Tracev(x) |
| # define Tracevv(x) |
| # define Tracec(c,x) |
| # define Tracecv(c,x) |
| #endif |
| |
| /* =========================================================================== |
| */ |
| #if CONFIG_GZIP_FAST == 0 |
| # define SMALL_MEM |
| #elif CONFIG_GZIP_FAST == 1 |
| # define MEDIUM_MEM |
| #elif CONFIG_GZIP_FAST == 2 |
| # define BIG_MEM |
| #else |
| # error "Invalid CONFIG_GZIP_FAST value" |
| #endif |
| |
| #ifndef INBUFSIZ |
| # ifdef SMALL_MEM |
| # define INBUFSIZ 0x2000 /* input buffer size */ |
| # else |
| # define INBUFSIZ 0x8000 /* input buffer size */ |
| # endif |
| #endif |
| |
| #ifndef OUTBUFSIZ |
| # ifdef SMALL_MEM |
| # define OUTBUFSIZ 8192 /* output buffer size */ |
| # else |
| # define OUTBUFSIZ 16384 /* output buffer size */ |
| # endif |
| #endif |
| |
| #ifndef DIST_BUFSIZE |
| # ifdef SMALL_MEM |
| # define DIST_BUFSIZE 0x2000 /* buffer for distances, see trees.c */ |
| # else |
| # define DIST_BUFSIZE 0x8000 /* buffer for distances, see trees.c */ |
| # endif |
| #endif |
| |
| /* gzip flag byte */ |
| #define ASCII_FLAG 0x01 /* bit 0 set: file probably ascii text */ |
| #define CONTINUATION 0x02 /* bit 1 set: continuation of multi-part gzip file */ |
| #define EXTRA_FIELD 0x04 /* bit 2 set: extra field present */ |
| #define ORIG_NAME 0x08 /* bit 3 set: original file name present */ |
| #define COMMENT 0x10 /* bit 4 set: file comment present */ |
| #define RESERVED 0xC0 /* bit 6,7: reserved */ |
| |
| /* internal file attribute */ |
| #define UNKNOWN 0xffff |
| #define BINARY 0 |
| #define ASCII 1 |
| |
| #ifndef WSIZE |
| # define WSIZE 0x8000 /* window size--must be a power of two, and */ |
| #endif /* at least 32K for zip's deflate method */ |
| |
| #define MIN_MATCH 3 |
| #define MAX_MATCH 258 |
| /* The minimum and maximum match lengths */ |
| |
| #define MIN_LOOKAHEAD (MAX_MATCH+MIN_MATCH+1) |
| /* Minimum amount of lookahead, except at the end of the input file. |
| * See deflate.c for comments about the MIN_MATCH+1. |
| */ |
| |
| #define MAX_DIST (WSIZE-MIN_LOOKAHEAD) |
| /* In order to simplify the code, particularly on 16 bit machines, match |
| * distances are limited to MAX_DIST instead of WSIZE. |
| */ |
| |
| #ifndef MAX_PATH_LEN |
| # define MAX_PATH_LEN 1024 /* max pathname length */ |
| #endif |
| |
| #define seekable() 0 /* force sequential output */ |
| #define translate_eol 0 /* no option -a yet */ |
| |
| #ifndef BITS |
| # define BITS 16 |
| #endif |
| #define INIT_BITS 9 /* Initial number of bits per code */ |
| |
| #define BIT_MASK 0x1f /* Mask for 'number of compression bits' */ |
| /* Mask 0x20 is reserved to mean a fourth header byte, and 0x40 is free. |
| * It's a pity that old uncompress does not check bit 0x20. That makes |
| * extension of the format actually undesirable because old compress |
| * would just crash on the new format instead of giving a meaningful |
| * error message. It does check the number of bits, but it's more |
| * helpful to say "unsupported format, get a new version" than |
| * "can only handle 16 bits". |
| */ |
| |
| #ifdef MAX_EXT_CHARS |
| # define MAX_SUFFIX MAX_EXT_CHARS |
| #else |
| # define MAX_SUFFIX 30 |
| #endif |
| |
| /* =========================================================================== |
| * Compile with MEDIUM_MEM to reduce the memory requirements or |
| * with SMALL_MEM to use as little memory as possible. Use BIG_MEM if the |
| * entire input file can be held in memory (not possible on 16 bit systems). |
| * Warning: defining these symbols affects HASH_BITS (see below) and thus |
| * affects the compression ratio. The compressed output |
| * is still correct, and might even be smaller in some cases. |
| */ |
| #ifdef SMALL_MEM |
| # define HASH_BITS 13 /* Number of bits used to hash strings */ |
| #endif |
| #ifdef MEDIUM_MEM |
| # define HASH_BITS 14 |
| #endif |
| #ifndef HASH_BITS |
| # define HASH_BITS 15 |
| /* For portability to 16 bit machines, do not use values above 15. */ |
| #endif |
| |
| #define HASH_SIZE (unsigned)(1<<HASH_BITS) |
| #define HASH_MASK (HASH_SIZE-1) |
| #define WMASK (WSIZE-1) |
| /* HASH_SIZE and WSIZE must be powers of two */ |
| #ifndef TOO_FAR |
| # define TOO_FAR 4096 |
| #endif |
| /* Matches of length 3 are discarded if their distance exceeds TOO_FAR */ |
| |
| /* =========================================================================== |
| * These types are not really 'char', 'short' and 'long' |
| */ |
| typedef uint8_t uch; |
| typedef uint16_t ush; |
| typedef uint32_t ulg; |
| typedef int32_t lng; |
| |
| typedef ush Pos; |
| typedef unsigned IPos; |
| /* A Pos is an index in the character window. We use short instead of int to |
| * save space in the various tables. IPos is used only for parameter passing. |
| */ |
| |
| enum { |
| WINDOW_SIZE = 2 * WSIZE, |
| /* window size, 2*WSIZE except for MMAP or BIG_MEM, where it is the |
| * input file length plus MIN_LOOKAHEAD. |
| */ |
| |
| #if !ENABLE_FEATURE_GZIP_LEVELS |
| |
| max_chain_length = 4096, |
| /* To speed up deflation, hash chains are never searched beyond this length. |
| * A higher limit improves compression ratio but degrades the speed. |
| */ |
| |
| max_lazy_match = 258, |
| /* Attempt to find a better match only when the current match is strictly |
| * smaller than this value. This mechanism is used only for compression |
| * levels >= 4. |
| */ |
| |
| max_insert_length = max_lazy_match, |
| /* Insert new strings in the hash table only if the match length |
| * is not greater than this length. This saves time but degrades compression. |
| * max_insert_length is used only for compression levels <= 3. |
| */ |
| |
| good_match = 32, |
| /* Use a faster search when the previous match is longer than this */ |
| |
| /* Values for max_lazy_match, good_match and max_chain_length, depending on |
| * the desired pack level (0..9). The values given below have been tuned to |
| * exclude worst case performance for pathological files. Better values may be |
| * found for specific files. |
| */ |
| |
| nice_match = 258, /* Stop searching when current match exceeds this */ |
| /* Note: the deflate() code requires max_lazy >= MIN_MATCH and max_chain >= 4 |
| * For deflate_fast() (levels <= 3) good is ignored and lazy has a different |
| * meaning. |
| */ |
| #endif /* ENABLE_FEATURE_GZIP_LEVELS */ |
| }; |
| |
| struct globals { |
| /* =========================================================================== */ |
| /* global buffers, allocated once */ |
| |
| #define DECLARE(type, array, size) \ |
| type * array |
| #define ALLOC(type, array, size) \ |
| array = xzalloc((size_t)(((size)+1L)/2) * 2*sizeof(type)) |
| #define FREE(array) \ |
| do { free(array); array = NULL; } while (0) |
| |
| /* buffer for literals or lengths */ |
| /* DECLARE(uch, l_buf, LIT_BUFSIZE); */ |
| DECLARE(uch, l_buf, INBUFSIZ); |
| |
| DECLARE(ush, d_buf, DIST_BUFSIZE); |
| DECLARE(uch, outbuf, OUTBUFSIZ); |
| |
| /* Sliding window. Input bytes are read into the second half of the window, |
| * and move to the first half later to keep a dictionary of at least WSIZE |
| * bytes. With this organization, matches are limited to a distance of |
| * WSIZE-MAX_MATCH bytes, but this ensures that IO is always |
| * performed with a length multiple of the block size. Also, it limits |
| * the window size to 64K, which is quite useful on MSDOS. |
| * To do: limit the window size to WSIZE+BSZ if SMALL_MEM (the code would |
| * be less efficient). |
| */ |
| DECLARE(uch, window, 2L * WSIZE); |
| |
| /* Link to older string with same hash index. To limit the size of this |
| * array to 64K, this link is maintained only for the last 32K strings. |
| * An index in this array is thus a window index modulo 32K. |
| */ |
| /* DECLARE(Pos, prev, WSIZE); */ |
| DECLARE(ush, prev, 1L << BITS); |
| |
| /* Heads of the hash chains or 0. */ |
| /* DECLARE(Pos, head, 1<<HASH_BITS); */ |
| #define head (G1.prev + WSIZE) /* hash head (see deflate.c) */ |
| |
| /* =========================================================================== */ |
| /* all members below are zeroed out in pack_gzip() for each next file */ |
| |
| uint32_t crc; /* shift register contents */ |
| /*uint32_t *crc_32_tab;*/ |
| |
| #if ENABLE_FEATURE_GZIP_LEVELS |
| unsigned max_chain_length; |
| unsigned max_lazy_match; |
| unsigned good_match; |
| unsigned nice_match; |
| #define max_chain_length (G1.max_chain_length) |
| #define max_lazy_match (G1.max_lazy_match) |
| #define good_match (G1.good_match) |
| #define nice_match (G1.nice_match) |
| #endif |
| |
| /* window position at the beginning of the current output block. Gets |
| * negative when the window is moved backwards. |
| */ |
| lng block_start; |
| |
| unsigned ins_h; /* hash index of string to be inserted */ |
| |
| /* 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 |
| */ |
| #define H_SHIFT ((HASH_BITS+MIN_MATCH-1) / MIN_MATCH) |
| |
| /* Length of the best match at previous step. Matches not greater than this |
| * are discarded. This is used in the lazy match evaluation. |
| */ |
| unsigned prev_length; |
| |
| unsigned strstart; /* start of string to insert */ |
| unsigned match_start; /* start of matching string */ |
| unsigned lookahead; /* number of valid bytes ahead in window */ |
| |
| /* number of input bytes */ |
| ulg isize; /* only 32 bits stored in .gz file */ |
| |
| /* bbox always use stdin/stdout */ |
| #define ifd STDIN_FILENO /* input file descriptor */ |
| #define ofd STDOUT_FILENO /* output file descriptor */ |
| |
| #ifdef DEBUG |
| unsigned insize; /* valid bytes in l_buf */ |
| #endif |
| unsigned outcnt; /* bytes in output buffer */ |
| smallint eofile; /* flag set at end of input file */ |
| |
| /* =========================================================================== |
| * Local data used by the "bit string" routines. |
| */ |
| |
| /* Output buffer. bits are inserted starting at the bottom (least significant |
| * bits). |
| */ |
| unsigned bi_buf; /* was unsigned short */ |
| |
| #undef BUF_SIZE |
| #define BUF_SIZE (int)(8 * sizeof(G1.bi_buf)) |
| |
| /* Number of bits used within bi_buf. (bi_buf might be implemented on |
| * more than 16 bits on some systems.) |
| */ |
| unsigned bi_valid; |
| |
| #ifdef DEBUG |
| ulg bits_sent; /* bit length of the compressed data */ |
| # define DEBUG_bits_sent(v) (void)(G1.bits_sent v) |
| #else |
| # define DEBUG_bits_sent(v) ((void)0) |
| #endif |
| }; |
| |
| #define G1 (*(ptr_to_globals - 1)) |
| |
| /* =========================================================================== |
| * Write the output buffer outbuf[0..outcnt-1] and update bytes_out. |
| * (used for the compressed data only) |
| */ |
| static void flush_outbuf(void) |
| { |
| if (G1.outcnt == 0) |
| return; |
| |
| xwrite(ofd, (char *) G1.outbuf, G1.outcnt); |
| G1.outcnt = 0; |
| } |
| |
| /* =========================================================================== |
| */ |
| /* put_8bit is used for the compressed output */ |
| #define put_8bit(c) \ |
| do { \ |
| G1.outbuf[G1.outcnt++] = (c); \ |
| if (G1.outcnt == OUTBUFSIZ) \ |
| flush_outbuf(); \ |
| } while (0) |
| |
| /* Output a 16 bit value, lsb first */ |
| static void put_16bit(ush w) |
| { |
| /* GCC 4.2.1 won't optimize out redundant loads of G1.outcnt |
| * (probably because of fear of aliasing with G1.outbuf[] |
| * stores), do it explicitly: |
| */ |
| unsigned outcnt = G1.outcnt; |
| uch *dst = &G1.outbuf[outcnt]; |
| |
| #if BB_UNALIGNED_MEMACCESS_OK && BB_LITTLE_ENDIAN |
| if (outcnt < OUTBUFSIZ-2) { |
| /* Common case */ |
| ush *dst16 = (void*) dst; |
| *dst16 = w; /* unaligned LSB 16-bit store */ |
| G1.outcnt = outcnt + 2; |
| return; |
| } |
| *dst = (uch)w; |
| w >>= 8; |
| G1.outcnt = ++outcnt; |
| #else |
| *dst = (uch)w; |
| w >>= 8; |
| if (outcnt < OUTBUFSIZ-2) { |
| /* Common case */ |
| dst[1] = w; |
| G1.outcnt = outcnt + 2; |
| return; |
| } |
| G1.outcnt = ++outcnt; |
| #endif |
| |
| /* Slowpath: we will need to do flush_outbuf() */ |
| if (outcnt == OUTBUFSIZ) |
| flush_outbuf(); /* here */ |
| put_8bit(w); /* or here */ |
| } |
| |
| #define OPTIMIZED_PUT_32BIT (CONFIG_GZIP_FAST > 0 && BB_UNALIGNED_MEMACCESS_OK && BB_LITTLE_ENDIAN) |
| static void put_32bit(ulg n) |
| { |
| if (OPTIMIZED_PUT_32BIT) { |
| unsigned outcnt = G1.outcnt; |
| if (outcnt < OUTBUFSIZ-4) { |
| /* Common case */ |
| ulg *dst32 = (void*) &G1.outbuf[outcnt]; |
| *dst32 = n; /* unaligned LSB 32-bit store */ |
| //bb_error_msg("%p", dst32); // store alignment debugging |
| G1.outcnt = outcnt + 4; |
| return; |
| } |
| } |
| put_16bit(n); |
| put_16bit(n >> 16); |
| } |
| static ALWAYS_INLINE void flush_outbuf_if_32bit_optimized(void) |
| { |
| /* If put_32bit() performs 32bit stores && it is used in send_bits() */ |
| if (OPTIMIZED_PUT_32BIT && BUF_SIZE > 16) |
| flush_outbuf(); |
| } |
| |
| /* =========================================================================== |
| * Run a set of bytes through the crc shift register. If s is a NULL |
| * pointer, then initialize the crc shift register contents instead. |
| * Return the current crc in either case. |
| */ |
| static void updcrc(uch * s, unsigned n) |
| { |
| G1.crc = crc32_block_endian0(G1.crc, s, n, global_crc32_table /*G1.crc_32_tab*/); |
| } |
| |
| /* =========================================================================== |
| * Read a new buffer from the current input file, perform end-of-line |
| * translation, and update the crc and input file size. |
| * IN assertion: size >= 2 (for end-of-line translation) |
| */ |
| static unsigned file_read(void *buf, unsigned size) |
| { |
| unsigned len; |
| |
| Assert(G1.insize == 0, "l_buf not empty"); |
| |
| len = safe_read(ifd, buf, size); |
| if (len == (unsigned)(-1) || len == 0) |
| return len; |
| |
| updcrc(buf, len); |
| G1.isize += len; |
| return len; |
| } |
| |
| /* =========================================================================== |
| * Send a value on a given number of bits. |
| * IN assertion: length <= 16 and value fits in length bits. |
| */ |
| static void send_bits(unsigned value, unsigned length) |
| { |
| unsigned new_buf; |
| |
| #ifdef DEBUG |
| Tracev((stderr, " l %2d v %4x ", length, value)); |
| Assert(length > 0 && length <= 15, "invalid length"); |
| DEBUG_bits_sent(+= length); |
| #endif |
| BUILD_BUG_ON(BUF_SIZE != 32 && BUF_SIZE != 16); |
| |
| new_buf = G1.bi_buf | (value << G1.bi_valid); |
| /* NB: the above may sometimes do "<< 32" shift (undefined) |
| * if check below is changed to "length > BUF_SIZE" instead of >= */ |
| length += G1.bi_valid; |
| |
| /* If bi_buf is full */ |
| if (length >= BUF_SIZE) { |
| /* ...use (valid) bits from bi_buf and |
| * (BUF_SIZE - bi_valid) bits from value, |
| * leaving (width - (BUF_SIZE-bi_valid)) unused bits in value. |
| */ |
| value >>= (BUF_SIZE - G1.bi_valid); |
| if (BUF_SIZE == 32) { |
| put_32bit(new_buf); |
| } else { /* 16 */ |
| put_16bit(new_buf); |
| } |
| new_buf = value; |
| length -= BUF_SIZE; |
| } |
| G1.bi_buf = new_buf; |
| G1.bi_valid = length; |
| } |
| |
| /* =========================================================================== |
| * Reverse the first len bits of a code, using straightforward code (a faster |
| * method would use a table) |
| * IN assertion: 1 <= len <= 15 |
| */ |
| static unsigned bi_reverse(unsigned code, int len) |
| { |
| unsigned res = 0; |
| |
| while (1) { |
| res |= code & 1; |
| if (--len <= 0) return res; |
| code >>= 1; |
| res <<= 1; |
| } |
| } |
| |
| /* =========================================================================== |
| * Write out any remaining bits in an incomplete byte. |
| */ |
| static void bi_windup(void) |
| { |
| unsigned bits = G1.bi_buf; |
| int cnt = G1.bi_valid; |
| |
| while (cnt > 0) { |
| put_8bit(bits); |
| bits >>= 8; |
| cnt -= 8; |
| } |
| G1.bi_buf = 0; |
| G1.bi_valid = 0; |
| DEBUG_bits_sent(= (G1.bits_sent + 7) & ~7); |
| } |
| |
| /* =========================================================================== |
| * 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) { |
| unsigned v = ((uint16_t)len) | ((~len) << 16); |
| put_32bit(v); |
| DEBUG_bits_sent(+= 2 * 16); |
| } |
| DEBUG_bits_sent(+= (ulg) len << 3); |
| while (len--) { |
| put_8bit(*buf++); |
| } |
| /* The above can 32-bit misalign outbuf */ |
| if (G1.outcnt & 3) /* syscalls are expensive, is it really misaligned? */ |
| flush_outbuf_if_32bit_optimized(); |
| } |
| |
| /* =========================================================================== |
| * Fill the window when the lookahead becomes insufficient. |
| * Updates strstart and lookahead, and sets eofile if end of input file. |
| * IN assertion: lookahead < MIN_LOOKAHEAD && strstart + lookahead > 0 |
| * OUT assertions: at least one byte has been read, or eofile is set; |
| * file reads are performed for at least two bytes (required for the |
| * translate_eol option). |
| */ |
| static void fill_window(void) |
| { |
| unsigned n, m; |
| unsigned more = WINDOW_SIZE - G1.lookahead - G1.strstart; |
| /* Amount of free space at the end of the window. */ |
| |
| /* If the window is almost full and there is insufficient lookahead, |
| * move the upper half to the lower one to make room in the upper half. |
| */ |
| if (more == (unsigned) -1) { |
| /* Very unlikely, but possible on 16 bit machine if strstart == 0 |
| * and lookahead == 1 (input done one byte at time) |
| */ |
| more--; |
| } else if (G1.strstart >= WSIZE + MAX_DIST) { |
| /* By the IN assertion, the window is not empty so we can't confuse |
| * more == 0 with more == 64K on a 16 bit machine. |
| */ |
| Assert(WINDOW_SIZE == 2 * WSIZE, "no sliding with BIG_MEM"); |
| |
| memcpy(G1.window, G1.window + WSIZE, WSIZE); |
| G1.match_start -= WSIZE; |
| G1.strstart -= WSIZE; /* we now have strstart >= MAX_DIST: */ |
| |
| G1.block_start -= WSIZE; |
| |
| for (n = 0; n < HASH_SIZE; n++) { |
| m = head[n]; |
| head[n] = (Pos) (m >= WSIZE ? m - WSIZE : 0); |
| } |
| for (n = 0; n < WSIZE; n++) { |
| m = G1.prev[n]; |
| G1.prev[n] = (Pos) (m >= WSIZE ? m - WSIZE : 0); |
| /* If n is not on any hash chain, prev[n] is garbage but |
| * its value will never be used. |
| */ |
| } |
| more += WSIZE; |
| } |
| /* At this point, more >= 2 */ |
| if (!G1.eofile) { |
| n = file_read(G1.window + G1.strstart + G1.lookahead, more); |
| if (n == 0 || n == (unsigned) -1) { |
| G1.eofile = 1; |
| } else { |
| G1.lookahead += n; |
| } |
| } |
| } |
| /* Both users fill window with the same loop: */ |
| static void fill_window_if_needed(void) |
| { |
| while (G1.lookahead < MIN_LOOKAHEAD && !G1.eofile) |
| fill_window(); |
| } |
| |
| /* =========================================================================== |
| * Set match_start to the longest match starting at the given string and |
| * return its length. Matches shorter or equal to prev_length are discarded, |
| * in which case the result is equal to prev_length and match_start is |
| * garbage. |
| * IN assertions: cur_match is the head of the hash chain for the current |
| * string (strstart) and its distance is <= MAX_DIST, and prev_length >= 1 |
| */ |
| |
| /* For MSDOS, OS/2 and 386 Unix, an optimized version is in match.asm or |
| * match.s. The code is functionally equivalent, so you can use the C version |
| * if desired. |
| */ |
| static int longest_match(IPos cur_match) |
| { |
| unsigned chain_length = max_chain_length; /* max hash chain length */ |
| uch *scan = G1.window + G1.strstart; /* current string */ |
| uch *match; /* matched string */ |
| int len; /* length of current match */ |
| int best_len = G1.prev_length; /* best match length so far */ |
| IPos limit = G1.strstart > (IPos) MAX_DIST ? G1.strstart - (IPos) MAX_DIST : 0; |
| /* Stop when cur_match becomes <= limit. To simplify the code, |
| * we prevent matches with the string of window index 0. |
| */ |
| |
| /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16. |
| * It is easy to get rid of this optimization if necessary. |
| */ |
| #if HASH_BITS < 8 || MAX_MATCH != 258 |
| # error Code too clever |
| #endif |
| uch *strend = G1.window + G1.strstart + MAX_MATCH; |
| uch scan_end1 = scan[best_len - 1]; |
| uch scan_end = scan[best_len]; |
| |
| /* Do not waste too much time if we already have a good match: */ |
| if (G1.prev_length >= good_match) { |
| chain_length >>= 2; |
| } |
| Assert(G1.strstart <= WINDOW_SIZE - MIN_LOOKAHEAD, "insufficient lookahead"); |
| |
| do { |
| Assert(cur_match < G1.strstart, "no future"); |
| match = G1.window + cur_match; |
| |
| /* Skip to next match if the match length cannot increase |
| * or if the match length is less than 2: |
| */ |
| if (match[best_len] != scan_end |
| || match[best_len - 1] != scan_end1 |
| || *match != *scan || *++match != scan[1] |
| ) { |
| continue; |
| } |
| |
| /* The check at best_len-1 can be removed because it will be made |
| * again later. (This heuristic is not always a win.) |
| * It is not necessary to compare scan[2] and match[2] since they |
| * are always equal when the other bytes match, given that |
| * the hash keys are equal and that HASH_BITS >= 8. |
| */ |
| scan += 2, match++; |
| |
| /* We check for insufficient lookahead only every 8th comparison; |
| * the 256th check will be made at strstart+258. |
| */ |
| do { |
| } while (*++scan == *++match && *++scan == *++match && |
| *++scan == *++match && *++scan == *++match && |
| *++scan == *++match && *++scan == *++match && |
| *++scan == *++match && *++scan == *++match && scan < strend); |
| |
| len = MAX_MATCH - (int) (strend - scan); |
| scan = strend - MAX_MATCH; |
| |
| if (len > best_len) { |
| G1.match_start = cur_match; |
| best_len = len; |
| if (len >= nice_match) |
| break; |
| scan_end1 = scan[best_len - 1]; |
| scan_end = scan[best_len]; |
| } |
| } while ((cur_match = G1.prev[cur_match & WMASK]) > limit |
| && --chain_length != 0); |
| |
| return best_len; |
| } |
| |
| #ifdef DEBUG |
| /* =========================================================================== |
| * Check that the match at match_start is indeed a match. |
| */ |
| static void check_match(IPos start, IPos match, int length) |
| { |
| /* check that the match is indeed a match */ |
| if (memcmp(G1.window + match, G1.window + start, length) != 0) { |
| bb_error_msg(" start %d, match %d, length %d", start, match, length); |
| bb_error_msg("invalid match"); |
| } |
| if (verbose > 1) { |
| bb_error_msg("\\[%d,%d]", start - match, length); |
| do { |
| bb_putchar_stderr(G1.window[start++]); |
| } while (--length != 0); |
| } |
| } |
| #else |
| # define check_match(start, match, length) ((void)0) |
| #endif |
| |
| |
| /* trees.c -- output deflated data using Huffman coding |
| * Copyright (C) 1992-1993 Jean-loup Gailly |
| * This is free software; you can redistribute it and/or modify it under the |
| * terms of the GNU General Public License, see the file COPYING. |
| */ |
| |
| /* PURPOSE |
| * Encode various sets of source values using variable-length |
| * binary code trees. |
| * |
| * DISCUSSION |
| * The PKZIP "deflation" process uses several Huffman trees. The more |
| * common source values are represented by shorter bit sequences. |
| * |
| * Each code tree is stored in the ZIP file in a compressed form |
| * which is itself a Huffman encoding of the lengths of |
| * all the code strings (in ascending order by source values). |
| * The actual code strings are reconstructed from the lengths in |
| * the UNZIP process, as described in the "application note" |
| * (APPNOTE.TXT) distributed as part of PKWARE's PKZIP program. |
| * |
| * REFERENCES |
| * Lynch, Thomas J. |
| * Data Compression: Techniques and Applications, pp. 53-55. |
| * Lifetime Learning Publications, 1985. ISBN 0-534-03418-7. |
| * |
| * Storer, James A. |
| * Data Compression: Methods and Theory, pp. 49-50. |
| * Computer Science Press, 1988. ISBN 0-7167-8156-5. |
| * |
| * Sedgewick, R. |
| * Algorithms, p290. |
| * Addison-Wesley, 1983. ISBN 0-201-06672-6. |
| * |
| * INTERFACE |
| * void ct_init() |
| * Allocate the match buffer, initialize the various tables [and save |
| * the location of the internal file attribute (ascii/binary) and |
| * method (DEFLATE/STORE) -- deleted in bbox] |
| * |
| * void ct_tally(int dist, int lc); |
| * Save the match info and tally the frequency counts. |
| * |
| * ulg flush_block(char *buf, ulg stored_len, int eof) |
| * Determine the best encoding for the current block: dynamic trees, |
| * static trees or store, and output the encoded block to the zip |
| * file. Returns the total compressed length for the file so far. |
| */ |
| |
| #define MAX_BITS 15 |
| /* All codes must not exceed MAX_BITS bits */ |
| |
| #define MAX_BL_BITS 7 |
| /* Bit length codes must not exceed MAX_BL_BITS bits */ |
| |
| #define LENGTH_CODES 29 |
| /* number of length codes, not counting the special END_BLOCK code */ |
| |
| #define LITERALS 256 |
| /* number of literal bytes 0..255 */ |
| |
| #define END_BLOCK 256 |
| /* end of block literal code */ |
| |
| #define L_CODES (LITERALS+1+LENGTH_CODES) |
| /* number of Literal or Length codes, including the END_BLOCK code */ |
| |
| #define D_CODES 30 |
| /* number of distance codes */ |
| |
| #define BL_CODES 19 |
| /* number of codes used to transfer the bit lengths */ |
| |
| /* extra bits for each length code */ |
| static const uint8_t extra_lbits[LENGTH_CODES] ALIGN1 = { |
| 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4, |
| 4, 4, 5, 5, 5, 5, 0 |
| }; |
| |
| /* extra bits for each distance code */ |
| static const uint8_t extra_dbits[D_CODES] ALIGN1 = { |
| 0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6, 7, 7, 8, 8, 9, 9, |
| 10, 10, 11, 11, 12, 12, 13, 13 |
| }; |
| |
| /* extra bits for each bit length code */ |
| static const uint8_t extra_blbits[BL_CODES] ALIGN1 = { |
| 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 3, 7 }; |
| |
| /* number of codes at each bit length for an optimal tree */ |
| static const uint8_t bl_order[BL_CODES] ALIGN1 = { |
| 16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15 }; |
| |
| #define STORED_BLOCK 0 |
| #define STATIC_TREES 1 |
| #define DYN_TREES 2 |
| /* The three kinds of block type */ |
| |
| #ifndef LIT_BUFSIZE |
| # ifdef SMALL_MEM |
| # define LIT_BUFSIZE 0x2000 |
| # else |
| # ifdef MEDIUM_MEM |
| # define LIT_BUFSIZE 0x4000 |
| # else |
| # define LIT_BUFSIZE 0x8000 |
| # endif |
| # endif |
| #endif |
| #ifndef DIST_BUFSIZE |
| # define DIST_BUFSIZE LIT_BUFSIZE |
| #endif |
| /* Sizes of match buffers for literals/lengths and distances. There are |
| * 4 reasons for limiting LIT_BUFSIZE to 64K: |
| * - frequencies can be kept in 16 bit counters |
| * - if compression is not successful for the first block, all input data is |
| * still in the window so we can still emit a stored block even when input |
| * comes from standard input. (This can also be done for all blocks if |
| * LIT_BUFSIZE is not greater than 32K.) |
| * - if compression is not successful for a file smaller than 64K, we can |
| * even emit a stored file instead of a stored block (saving 5 bytes). |
| * - creating new Huffman trees less frequently may not provide fast |
| * adaptation to changes in the input data statistics. (Take for |
| * example a binary file with poorly compressible code followed by |
| * a highly compressible string table.) Smaller buffer sizes give |
| * fast adaptation but have of course the overhead of transmitting trees |
| * more frequently. |
| * - I can't count above 4 |
| * The current code is general and allows DIST_BUFSIZE < LIT_BUFSIZE (to save |
| * memory at the expense of compression). Some optimizations would be possible |
| * if we rely on DIST_BUFSIZE == LIT_BUFSIZE. |
| */ |
| #define REP_3_6 16 |
| /* repeat previous bit length 3-6 times (2 bits of repeat count) */ |
| #define REPZ_3_10 17 |
| /* repeat a zero length 3-10 times (3 bits of repeat count) */ |
| #define REPZ_11_138 18 |
| /* repeat a zero length 11-138 times (7 bits of repeat count) */ |
| |
| /* =========================================================================== |
| */ |
| /* Data structure describing a single value and its code string. */ |
| typedef struct ct_data { |
| union { |
| ush freq; /* frequency count */ |
| ush code; /* bit string */ |
| } fc; |
| union { |
| ush dad; /* father node in Huffman tree */ |
| ush len; /* length of bit string */ |
| } dl; |
| } ct_data; |
| |
| #define Freq fc.freq |
| #define Code fc.code |
| #define Dad dl.dad |
| #define Len dl.len |
| |
| #define HEAP_SIZE (2*L_CODES + 1) |
| /* maximum heap size */ |
| |
| typedef struct tree_desc { |
| ct_data *dyn_tree; /* the dynamic tree */ |
| ct_data *static_tree; /* corresponding static tree or NULL */ |
| const uint8_t *extra_bits; /* extra bits for each code or NULL */ |
| int extra_base; /* base index for extra_bits */ |
| int elems; /* max number of elements in the tree */ |
| int max_length; /* max bit length for the codes */ |
| int max_code; /* largest code with non zero frequency */ |
| } tree_desc; |
| |
| struct globals2 { |
| |
| ush heap[HEAP_SIZE]; /* heap used to build the Huffman trees */ |
| int heap_len; /* number of elements in the heap */ |
| int heap_max; /* element of largest frequency */ |
| |
| /* The sons of heap[n] are heap[2*n] and heap[2*n+1]. heap[0] is not used. |
| * The same heap array is used to build all trees. |
| */ |
| |
| ct_data dyn_ltree[HEAP_SIZE]; /* literal and length tree */ |
| ct_data dyn_dtree[2 * D_CODES + 1]; /* distance tree */ |
| |
| ct_data static_ltree[L_CODES + 2]; |
| |
| /* The static literal tree. Since the bit lengths are imposed, there is no |
| * need for the L_CODES extra codes used during heap construction. However |
| * The codes 286 and 287 are needed to build a canonical tree (see ct_init |
| * below). |
| */ |
| |
| ct_data static_dtree[D_CODES]; |
| |
| /* The static distance tree. (Actually a trivial tree since all codes use |
| * 5 bits.) |
| */ |
| |
| ct_data bl_tree[2 * BL_CODES + 1]; |
| |
| /* Huffman tree for the bit lengths */ |
| |
| tree_desc l_desc; |
| tree_desc d_desc; |
| tree_desc bl_desc; |
| |
| ush bl_count[MAX_BITS + 1]; |
| |
| /* The lengths of the bit length codes are sent in order of decreasing |
| * probability, to avoid transmitting the lengths for unused bit length codes. |
| */ |
| |
| uch depth[2 * L_CODES + 1]; |
| |
| /* Depth of each subtree used as tie breaker for trees of equal frequency */ |
| |
| uch length_code[MAX_MATCH - MIN_MATCH + 1]; |
| |
| /* length code for each normalized match length (0 == MIN_MATCH) */ |
| |
| uch dist_code[512]; |
| |
| /* distance codes. The first 256 values correspond to the distances |
| * 3 .. 258, the last 256 values correspond to the top 8 bits of |
| * the 15 bit distances. |
| */ |
| |
| int base_length[LENGTH_CODES]; |
| |
| /* First normalized length for each code (0 = MIN_MATCH) */ |
| |
| int base_dist[D_CODES]; |
| |
| /* First normalized distance for each code (0 = distance of 1) */ |
| |
| uch flag_buf[LIT_BUFSIZE / 8]; |
| |
| /* flag_buf is a bit array distinguishing literals from lengths in |
| * l_buf, thus indicating the presence or absence of a distance. |
| */ |
| |
| unsigned last_lit; /* running index in l_buf */ |
| unsigned last_dist; /* running index in d_buf */ |
| unsigned last_flags; /* running index in flag_buf */ |
| uch flags; /* current flags not yet saved in flag_buf */ |
| uch flag_bit; /* current bit used in flags */ |
| |
| /* bits are filled in flags starting at bit 0 (least significant). |
| * Note: these flags are overkill in the current code since we don't |
| * take advantage of DIST_BUFSIZE == LIT_BUFSIZE. |
| */ |
| |
| ulg opt_len; /* bit length of current block with optimal trees */ |
| ulg static_len; /* bit length of current block with static trees */ |
| |
| // ulg compressed_len; /* total bit length of compressed file */ |
| }; |
| |
| #define G2ptr ((struct globals2*)(ptr_to_globals)) |
| #define G2 (*G2ptr) |
| |
| /* =========================================================================== |
| */ |
| #ifndef DEBUG |
| /* Send a code of the given tree. c and tree must not have side effects */ |
| # define SEND_CODE(c, tree) send_bits(tree[c].Code, tree[c].Len) |
| #else |
| # define SEND_CODE(c, tree) \ |
| { \ |
| if (verbose > 1) bb_error_msg("\ncd %3d ", (c)); \ |
| send_bits(tree[c].Code, tree[c].Len); \ |
| } |
| #endif |
| |
| #define D_CODE(dist) \ |
| ((dist) < 256 ? G2.dist_code[dist] : G2.dist_code[256 + ((dist)>>7)]) |
| /* Mapping from a distance to a distance code. dist is the distance - 1 and |
| * must not have side effects. dist_code[256] and dist_code[257] are never |
| * used. |
| * The arguments must not have side effects. |
| */ |
| |
| /* =========================================================================== |
| * Initialize a new block. |
| */ |
| static void init_block(void) |
| { |
| int n; /* iterates over tree elements */ |
| |
| /* Initialize the trees. */ |
| for (n = 0; n < L_CODES; n++) |
| G2.dyn_ltree[n].Freq = 0; |
| for (n = 0; n < D_CODES; n++) |
| G2.dyn_dtree[n].Freq = 0; |
| for (n = 0; n < BL_CODES; n++) |
| G2.bl_tree[n].Freq = 0; |
| |
| G2.dyn_ltree[END_BLOCK].Freq = 1; |
| G2.opt_len = G2.static_len = 0; |
| G2.last_lit = G2.last_dist = G2.last_flags = 0; |
| G2.flags = 0; |
| G2.flag_bit = 1; |
| } |
| |
| /* =========================================================================== |
| * Restore the heap property by moving down the tree starting at node k, |
| * exchanging a node with the smallest of its two sons if necessary, stopping |
| * when the heap property is re-established (each father smaller than its |
| * two sons). |
| */ |
| |
| /* Compares to subtrees, using the tree depth as tie breaker when |
| * the subtrees have equal frequency. This minimizes the worst case length. */ |
| #define SMALLER(tree, n, m) \ |
| (tree[n].Freq < tree[m].Freq \ |
| || (tree[n].Freq == tree[m].Freq && G2.depth[n] <= G2.depth[m])) |
| |
| static void pqdownheap(ct_data * tree, int k) |
| { |
| int v = G2.heap[k]; |
| int j = k << 1; /* left son of k */ |
| |
| while (j <= G2.heap_len) { |
| /* Set j to the smallest of the two sons: */ |
| if (j < G2.heap_len && SMALLER(tree, G2.heap[j + 1], G2.heap[j])) |
| j++; |
| |
| /* Exit if v is smaller than both sons */ |
| if (SMALLER(tree, v, G2.heap[j])) |
| break; |
| |
| /* Exchange v with the smallest son */ |
| G2.heap[k] = G2.heap[j]; |
| k = j; |
| |
| /* And continue down the tree, setting j to the left son of k */ |
| j <<= 1; |
| } |
| G2.heap[k] = v; |
| } |
| |
| /* =========================================================================== |
| * Compute the optimal bit lengths for a tree and update the total bit length |
| * for the current block. |
| * IN assertion: the fields freq and dad are set, heap[heap_max] and |
| * above are the tree nodes sorted by increasing frequency. |
| * OUT assertions: the field len is set to the optimal bit length, the |
| * array bl_count contains the frequencies for each bit length. |
| * The length opt_len is updated; static_len is also updated if stree is |
| * not null. |
| */ |
| static void gen_bitlen(tree_desc * desc) |
| { |
| ct_data *tree = desc->dyn_tree; |
| const uint8_t *extra = desc->extra_bits; |
| int base = desc->extra_base; |
| int max_code = desc->max_code; |
| int max_length = desc->max_length; |
| ct_data *stree = desc->static_tree; |
| int h; /* heap index */ |
| int n, m; /* iterate over the tree elements */ |
| int bits; /* bit length */ |
| int xbits; /* extra bits */ |
| ush f; /* frequency */ |
| int overflow = 0; /* number of elements with bit length too large */ |
| |
| for (bits = 0; bits <= MAX_BITS; bits++) |
| G2.bl_count[bits] = 0; |
| |
| /* In a first pass, compute the optimal bit lengths (which may |
| * overflow in the case of the bit length tree). |
| */ |
| tree[G2.heap[G2.heap_max]].Len = 0; /* root of the heap */ |
| |
| for (h = G2.heap_max + 1; h < HEAP_SIZE; h++) { |
| n = G2.heap[h]; |
| bits = tree[tree[n].Dad].Len + 1; |
| if (bits > max_length) { |
| bits = max_length; |
| overflow++; |
| } |
| tree[n].Len = (ush) bits; |
| /* We overwrite tree[n].Dad which is no longer needed */ |
| |
| if (n > max_code) |
| continue; /* not a leaf node */ |
| |
| G2.bl_count[bits]++; |
| xbits = 0; |
| if (n >= base) |
| xbits = extra[n - base]; |
| f = tree[n].Freq; |
| G2.opt_len += (ulg) f *(bits + xbits); |
| |
| if (stree) |
| G2.static_len += (ulg) f * (stree[n].Len + xbits); |
| } |
| if (overflow == 0) |
| return; |
| |
| Trace((stderr, "\nbit length overflow\n")); |
| /* This happens for example on obj2 and pic of the Calgary corpus */ |
| |
| /* Find the first bit length which could increase: */ |
| do { |
| bits = max_length - 1; |
| while (G2.bl_count[bits] == 0) |
| bits--; |
| G2.bl_count[bits]--; /* move one leaf down the tree */ |
| G2.bl_count[bits + 1] += 2; /* move one overflow item as its brother */ |
| G2.bl_count[max_length]--; |
| /* The brother of the overflow item also moves one step up, |
| * but this does not affect bl_count[max_length] |
| */ |
| overflow -= 2; |
| } while (overflow > 0); |
| |
| /* Now recompute all bit lengths, scanning in increasing frequency. |
| * h is still equal to HEAP_SIZE. (It is simpler to reconstruct all |
| * lengths instead of fixing only the wrong ones. This idea is taken |
| * from 'ar' written by Haruhiko Okumura.) |
| */ |
| for (bits = max_length; bits != 0; bits--) { |
| n = G2.bl_count[bits]; |
| while (n != 0) { |
| m = G2.heap[--h]; |
| if (m > max_code) |
| continue; |
| if (tree[m].Len != (unsigned) bits) { |
| Trace((stderr, "code %d bits %d->%d\n", m, tree[m].Len, bits)); |
| G2.opt_len += ((int32_t) bits - tree[m].Len) * tree[m].Freq; |
| tree[m].Len = bits; |
| } |
| n--; |
| } |
| } |
| } |
| |
| /* =========================================================================== |
| * Generate the codes for a given tree and bit counts (which need not be |
| * optimal). |
| * IN assertion: the array bl_count contains the bit length statistics for |
| * the given tree and the field len is set for all tree elements. |
| * OUT assertion: the field code is set for all tree elements of non |
| * zero code length. |
| */ |
| static void gen_codes(ct_data * tree, int max_code) |
| { |
| ush next_code[MAX_BITS + 1]; /* next code value for each bit length */ |
| ush code = 0; /* running code value */ |
| int bits; /* bit index */ |
| int n; /* code index */ |
| |
| /* The distribution counts are first used to generate the code values |
| * without bit reversal. |
| */ |
| for (bits = 1; bits <= MAX_BITS; bits++) { |
| next_code[bits] = code = (code + G2.bl_count[bits - 1]) << 1; |
| } |
| /* Check that the bit counts in bl_count are consistent. The last code |
| * must be all ones. |
| */ |
| Assert(code + G2.bl_count[MAX_BITS] - 1 == (1 << MAX_BITS) - 1, |
| "inconsistent bit counts"); |
| Tracev((stderr, "\ngen_codes: max_code %d ", max_code)); |
| |
| for (n = 0; n <= max_code; n++) { |
| int len = tree[n].Len; |
| |
| if (len == 0) |
| continue; |
| /* Now reverse the bits */ |
| tree[n].Code = bi_reverse(next_code[len]++, len); |
| |
| Tracec(tree != G2.static_ltree, |
| (stderr, "\nn %3d %c l %2d c %4x (%x) ", n, |
| (n > ' ' ? n : ' '), len, tree[n].Code, |
| next_code[len] - 1)); |
| } |
| } |
| |
| /* =========================================================================== |
| * Construct one Huffman tree and assigns the code bit strings and lengths. |
| * Update the total bit length for the current block. |
| * IN assertion: the field freq is set for all tree elements. |
| * OUT assertions: the fields len and code are set to the optimal bit length |
| * and corresponding code. The length opt_len is updated; static_len is |
| * also updated if stree is not null. The field max_code is set. |
| */ |
| |
| /* Remove the smallest element from the heap and recreate the heap with |
| * one less element. Updates heap and heap_len. */ |
| |
| #define SMALLEST 1 |
| /* Index within the heap array of least frequent node in the Huffman tree */ |
| |
| #define PQREMOVE(tree, top) \ |
| do { \ |
| top = G2.heap[SMALLEST]; \ |
| G2.heap[SMALLEST] = G2.heap[G2.heap_len--]; \ |
| pqdownheap(tree, SMALLEST); \ |
| } while (0) |
| |
| static void build_tree(tree_desc * desc) |
| { |
| ct_data *tree = desc->dyn_tree; |
| ct_data *stree = desc->static_tree; |
| int elems = desc->elems; |
| int n, m; /* iterate over heap elements */ |
| int max_code = -1; /* largest code with non zero frequency */ |
| int node = elems; /* next internal node of the tree */ |
| |
| /* Construct the initial heap, with least frequent element in |
| * heap[SMALLEST]. The sons of heap[n] are heap[2*n] and heap[2*n+1]. |
| * heap[0] is not used. |
| */ |
| G2.heap_len = 0; |
| G2.heap_max = HEAP_SIZE; |
| |
| for (n = 0; n < elems; n++) { |
| if (tree[n].Freq != 0) { |
| G2.heap[++G2.heap_len] = max_code = n; |
| G2.depth[n] = 0; |
| } else { |
| tree[n].Len = 0; |
| } |
| } |
| |
| /* The pkzip format requires that at least one distance code exists, |
| * and that at least one bit should be sent even if there is only one |
| * possible code. So to avoid special checks later on we force at least |
| * two codes of non zero frequency. |
| */ |
| while (G2.heap_len < 2) { |
| int new = G2.heap[++G2.heap_len] = (max_code < 2 ? ++max_code : 0); |
| |
| tree[new].Freq = 1; |
| G2.depth[new] = 0; |
| G2.opt_len--; |
| if (stree) |
| G2.static_len -= stree[new].Len; |
| /* new is 0 or 1 so it does not have extra bits */ |
| } |
| desc->max_code = max_code; |
| |
| /* The elements heap[heap_len/2+1 .. heap_len] are leaves of the tree, |
| * establish sub-heaps of increasing lengths: |
| */ |
| for (n = G2.heap_len / 2; n >= 1; n--) |
| pqdownheap(tree, n); |
| |
| /* Construct the Huffman tree by repeatedly combining the least two |
| * frequent nodes. |
| */ |
| do { |
| PQREMOVE(tree, n); /* n = node of least frequency */ |
| m = G2.heap[SMALLEST]; /* m = node of next least frequency */ |
| |
| G2.heap[--G2.heap_max] = n; /* keep the nodes sorted by frequency */ |
| G2.heap[--G2.heap_max] = m; |
| |
| /* Create a new node father of n and m */ |
| tree[node].Freq = tree[n].Freq + tree[m].Freq; |
| G2.depth[node] = MAX(G2.depth[n], G2.depth[m]) + 1; |
| tree[n].Dad = tree[m].Dad = (ush) node; |
| #ifdef DUMP_BL_TREE |
| if (tree == G2.bl_tree) { |
| bb_error_msg("\nnode %d(%d), sons %d(%d) %d(%d)", |
| node, tree[node].Freq, n, tree[n].Freq, m, tree[m].Freq); |
| } |
| #endif |
| /* and insert the new node in the heap */ |
| G2.heap[SMALLEST] = node++; |
| pqdownheap(tree, SMALLEST); |
| } while (G2.heap_len >= 2); |
| |
| G2.heap[--G2.heap_max] = G2.heap[SMALLEST]; |
| |
| /* At this point, the fields freq and dad are set. We can now |
| * generate the bit lengths. |
| */ |
| gen_bitlen((tree_desc *) desc); |
| |
| /* The field len is now set, we can generate the bit codes */ |
| gen_codes((ct_data *) tree, max_code); |
| } |
| |
| /* =========================================================================== |
| * Scan a literal or distance tree to determine the frequencies of the codes |
| * in the bit length tree. Updates opt_len to take into account the repeat |
| * counts. (The contribution of the bit length codes will be added later |
| * during the construction of bl_tree.) |
| */ |
| static void scan_tree(ct_data * tree, int max_code) |
| { |
| int n; /* iterates over all tree elements */ |
| int prevlen = -1; /* last emitted length */ |
| int curlen; /* length of current code */ |
| int nextlen = tree[0].Len; /* length of next code */ |
| int count = 0; /* repeat count of the current code */ |
| int max_count = 7; /* max repeat count */ |
| int min_count = 4; /* min repeat count */ |
| |
| if (nextlen == 0) { |
| max_count = 138; |
| min_count = 3; |
| } |
| tree[max_code + 1].Len = 0xffff; /* guard */ |
| |
| for (n = 0; n <= max_code; n++) { |
| curlen = nextlen; |
| nextlen = tree[n + 1].Len; |
| if (++count < max_count && curlen == nextlen) |
| continue; |
| |
| if (count < min_count) { |
| G2.bl_tree[curlen].Freq += count; |
| } else if (curlen != 0) { |
| if (curlen != prevlen) |
| G2.bl_tree[curlen].Freq++; |
| G2.bl_tree[REP_3_6].Freq++; |
| } else if (count <= 10) { |
| G2.bl_tree[REPZ_3_10].Freq++; |
| } else { |
| G2.bl_tree[REPZ_11_138].Freq++; |
| } |
| count = 0; |
| prevlen = curlen; |
| |
| max_count = 7; |
| min_count = 4; |
| if (nextlen == 0) { |
| max_count = 138; |
| min_count = 3; |
| } else if (curlen == nextlen) { |
| max_count = 6; |
| min_count = 3; |
| } |
| } |
| } |
| |
| /* =========================================================================== |
| * Send a literal or distance tree in compressed form, using the codes in |
| * bl_tree. |
| */ |
| static void send_tree(ct_data * tree, int max_code) |
| { |
| int n; /* iterates over all tree elements */ |
| int prevlen = -1; /* last emitted length */ |
| int curlen; /* length of current code */ |
| int nextlen = tree[0].Len; /* length of next code */ |
| int count = 0; /* repeat count of the current code */ |
| int max_count = 7; /* max repeat count */ |
| int min_count = 4; /* min repeat count */ |
| |
| /* tree[max_code+1].Len = -1; *//* guard already set */ |
| if (nextlen == 0) |
| max_count = 138, min_count = 3; |
| |
| for (n = 0; n <= max_code; n++) { |
| curlen = nextlen; |
| nextlen = tree[n + 1].Len; |
| if (++count < max_count && curlen == nextlen) { |
| continue; |
| } else if (count < min_count) { |
| do { |
| SEND_CODE(curlen, G2.bl_tree); |
| } while (--count); |
| } else if (curlen != 0) { |
| if (curlen != prevlen) { |
| SEND_CODE(curlen, G2.bl_tree); |
| count--; |
| } |
| Assert(count >= 3 && count <= 6, " 3_6?"); |
| SEND_CODE(REP_3_6, G2.bl_tree); |
| send_bits(count - 3, 2); |
| } else if (count <= 10) { |
| SEND_CODE(REPZ_3_10, G2.bl_tree); |
| send_bits(count - 3, 3); |
| } else { |
| SEND_CODE(REPZ_11_138, G2.bl_tree); |
| send_bits(count - 11, 7); |
| } |
| count = 0; |
| prevlen = curlen; |
| if (nextlen == 0) { |
| max_count = 138; |
| min_count = 3; |
| } else if (curlen == nextlen) { |
| max_count = 6; |
| min_count = 3; |
| } else { |
| max_count = 7; |
| min_count = 4; |
| } |
| } |
| } |
| |
| /* =========================================================================== |
| * Construct the Huffman tree for the bit lengths and return the index in |
| * bl_order of the last bit length code to send. |
| */ |
| static int build_bl_tree(void) |
| { |
| int max_blindex; /* index of last bit length code of non zero freq */ |
| |
| /* Determine the bit length frequencies for literal and distance trees */ |
| scan_tree(G2.dyn_ltree, G2.l_desc.max_code); |
| scan_tree(G2.dyn_dtree, G2.d_desc.max_code); |
| |
| /* Build the bit length tree: */ |
| build_tree(&G2.bl_desc); |
| /* opt_len now includes the length of the tree representations, except |
| * the lengths of the bit lengths codes and the 5+5+4 bits for the counts. |
| */ |
| |
| /* Determine the number of bit length codes to send. The pkzip format |
| * requires that at least 4 bit length codes be sent. (appnote.txt says |
| * 3 but the actual value used is 4.) |
| */ |
| for (max_blindex = BL_CODES - 1; max_blindex >= 3; max_blindex--) { |
| if (G2.bl_tree[bl_order[max_blindex]].Len != 0) |
| break; |
| } |
| /* Update opt_len to include the bit length tree and counts */ |
| G2.opt_len += 3 * (max_blindex + 1) + 5 + 5 + 4; |
| Tracev((stderr, "\ndyn trees: dyn %ld, stat %ld", (long)G2.opt_len, (long)G2.static_len)); |
| |
| return max_blindex; |
| } |
| |
| /* =========================================================================== |
| * Send the header for a block using dynamic Huffman trees: the counts, the |
| * lengths of the bit length codes, the literal tree and the distance tree. |
| * IN assertion: lcodes >= 257, dcodes >= 1, blcodes >= 4. |
| */ |
| static void send_all_trees(int lcodes, int dcodes, int blcodes) |
| { |
| int rank; /* index in bl_order */ |
| |
| Assert(lcodes >= 257 && dcodes >= 1 && blcodes >= 4, "not enough codes"); |
| Assert(lcodes <= L_CODES && dcodes <= D_CODES |
| && blcodes <= BL_CODES, "too many codes"); |
| Tracev((stderr, "\nbl counts: ")); |
| send_bits(lcodes - 257, 5); /* not +255 as stated in appnote.txt */ |
| send_bits(dcodes - 1, 5); |
| send_bits(blcodes - 4, 4); /* not -3 as stated in appnote.txt */ |
| for (rank = 0; rank < blcodes; rank++) { |
| Tracev((stderr, "\nbl code %2d ", bl_order[rank])); |
| send_bits(G2.bl_tree[bl_order[rank]].Len, 3); |
| } |
| Tracev((stderr, "\nbl tree: sent %ld", (long)G1.bits_sent)); |
| |
| send_tree((ct_data *) G2.dyn_ltree, lcodes - 1); /* send the literal tree */ |
| Tracev((stderr, "\nlit tree: sent %ld", (long)G1.bits_sent)); |
| |
| send_tree((ct_data *) G2.dyn_dtree, dcodes - 1); /* send the distance tree */ |
| Tracev((stderr, "\ndist tree: sent %ld", (long)G1.bits_sent)); |
| } |
| |
| /* =========================================================================== |
| * Save the match info and tally the frequency counts. Return true if |
| * the current block must be flushed. |
| */ |
| static int ct_tally(int dist, int lc) |
| { |
| G1.l_buf[G2.last_lit++] = lc; |
| if (dist == 0) { |
| /* lc is the unmatched char */ |
| G2.dyn_ltree[lc].Freq++; |
| } else { |
| /* Here, lc is the match length - MIN_MATCH */ |
| dist--; /* dist = match distance - 1 */ |
| Assert((ush) dist < (ush) MAX_DIST |
| && (ush) lc <= (ush) (MAX_MATCH - MIN_MATCH) |
| && (ush) D_CODE(dist) < (ush) D_CODES, "ct_tally: bad match" |
| ); |
| |
| G2.dyn_ltree[G2.length_code[lc] + LITERALS + 1].Freq++; |
| G2.dyn_dtree[D_CODE(dist)].Freq++; |
| |
| G1.d_buf[G2.last_dist++] = dist; |
| G2.flags |= G2.flag_bit; |
| } |
| G2.flag_bit <<= 1; |
| |
| /* Output the flags if they fill a byte: */ |
| if ((G2.last_lit & 7) == 0) { |
| G2.flag_buf[G2.last_flags++] = G2.flags; |
| G2.flags = 0; |
| G2.flag_bit = 1; |
| } |
| /* Try to guess if it is profitable to stop the current block here */ |
| if ((G2.last_lit & 0xfff) == 0) { |
| /* Compute an upper bound for the compressed length */ |
| ulg out_length = G2.last_lit * 8L; |
| ulg in_length = (ulg) G1.strstart - G1.block_start; |
| int dcode; |
| |
| for (dcode = 0; dcode < D_CODES; dcode++) { |
| out_length += G2.dyn_dtree[dcode].Freq * (5L + extra_dbits[dcode]); |
| } |
| out_length >>= 3; |
| Trace((stderr, |
| "\nlast_lit %u, last_dist %u, in %ld, out ~%ld(%ld%%) ", |
| G2.last_lit, G2.last_dist, |
| (long)in_length, (long)out_length, |
| 100L - out_length * 100L / in_length)); |
| if (G2.last_dist < G2.last_lit / 2 && out_length < in_length / 2) |
| return 1; |
| } |
| return (G2.last_lit == LIT_BUFSIZE - 1 || G2.last_dist == DIST_BUFSIZE); |
| /* We avoid equality with LIT_BUFSIZE because of wraparound at 64K |
| * on 16 bit machines and because stored blocks are restricted to |
| * 64K-1 bytes. |
| */ |
| } |
| |
| /* =========================================================================== |
| * Send the block data compressed using the given Huffman trees |
| */ |
| static void compress_block(ct_data * ltree, ct_data * dtree) |
| { |
| unsigned dist; /* distance of matched string */ |
| int lc; /* match length or unmatched char (if dist == 0) */ |
| unsigned lx = 0; /* running index in l_buf */ |
| unsigned dx = 0; /* running index in d_buf */ |
| unsigned fx = 0; /* running index in flag_buf */ |
| uch flag = 0; /* current flags */ |
| unsigned code; /* the code to send */ |
| int extra; /* number of extra bits to send */ |
| |
| if (G2.last_lit != 0) do { |
| if ((lx & 7) == 0) |
| flag = G2.flag_buf[fx++]; |
| lc = G1.l_buf[lx++]; |
| if ((flag & 1) == 0) { |
| SEND_CODE(lc, ltree); /* send a literal byte */ |
| Tracecv(lc > ' ', (stderr, " '%c' ", lc)); |
| } else { |
| /* Here, lc is the match length - MIN_MATCH */ |
| code = G2.length_code[lc]; |
| SEND_CODE(code + LITERALS + 1, ltree); /* send the length code */ |
| extra = extra_lbits[code]; |
| if (extra != 0) { |
| lc -= G2.base_length[code]; |
| send_bits(lc, extra); /* send the extra length bits */ |
| } |
| dist = G1.d_buf[dx++]; |
| /* Here, dist is the match distance - 1 */ |
| code = D_CODE(dist); |
| Assert(code < D_CODES, "bad d_code"); |
| |
| SEND_CODE(code, dtree); /* send the distance code */ |
| extra = extra_dbits[code]; |
| if (extra != 0) { |
| dist -= G2.base_dist[code]; |
| send_bits(dist, extra); /* send the extra distance bits */ |
| } |
| } /* literal or match pair ? */ |
| flag >>= 1; |
| } while (lx < G2.last_lit); |
| |
| SEND_CODE(END_BLOCK, ltree); |
| } |
| |
| /* =========================================================================== |
| * Determine the best encoding for the current block: dynamic trees, static |
| * trees or store, and output the encoded block to the zip file. This function |
| * returns the total compressed length for the file so far. |
| */ |
| static void flush_block(char *buf, ulg stored_len, int eof) |
| { |
| ulg opt_lenb, static_lenb; /* opt_len and static_len in bytes */ |
| int max_blindex; /* index of last bit length code of non zero freq */ |
| |
| G2.flag_buf[G2.last_flags] = G2.flags; /* Save the flags for the last 8 items */ |
| |
| /* Construct the literal and distance trees */ |
| build_tree(&G2.l_desc); |
| Tracev((stderr, "\nlit data: dyn %ld, stat %ld", (long)G2.opt_len, (long)G2.static_len)); |
| |
| build_tree(&G2.d_desc); |
| Tracev((stderr, "\ndist data: dyn %ld, stat %ld", (long)G2.opt_len, (long)G2.static_len)); |
| /* At this point, opt_len and static_len are the total bit lengths of |
| * the compressed block data, excluding the tree representations. |
| */ |
| |
| /* Build the bit length tree for the above two trees, and get the index |
| * in bl_order of the last bit length code to send. |
| */ |
| max_blindex = build_bl_tree(); |
| |
| /* Determine the best encoding. Compute first the block length in bytes */ |
| opt_lenb = (G2.opt_len + 3 + 7) >> 3; |
| static_lenb = (G2.static_len + 3 + 7) >> 3; |
| |
| Trace((stderr, |
| "\nopt %lu(%lu) stat %lu(%lu) stored %lu lit %u dist %u ", |
| (unsigned long)opt_lenb, (unsigned long)G2.opt_len, |
| (unsigned long)static_lenb, (unsigned long)G2.static_len, |
| (unsigned long)stored_len, |
| G2.last_lit, G2.last_dist)); |
| |
| if (static_lenb <= opt_lenb) |
| opt_lenb = static_lenb; |
| |
| /* If compression failed and this is the first and last block, |
| * and if the zip file can be seeked (to rewrite the local header), |
| * the whole file is transformed into a stored file: |
| */ |
| // seekable() is constant FALSE in busybox, and G2.compressed_len is disabled |
| // (this was the only user) |
| // if (stored_len <= opt_lenb && eof && G2.compressed_len == 0L && seekable()) { |
| // /* Since LIT_BUFSIZE <= 2*WSIZE, the input data must be there: */ |
| // if (buf == NULL) |
| // bb_error_msg("block vanished"); |
| // |
| // G2.compressed_len = stored_len << 3; |
| // copy_block(buf, (unsigned) stored_len, 0); /* without header */ |
| // } else |
| if (stored_len + 4 <= opt_lenb && buf != NULL) { |
| /* 4: two words for the lengths */ |
| /* The test buf != NULL is only necessary if LIT_BUFSIZE > WSIZE. |
| * Otherwise we can't have processed more than WSIZE input bytes since |
| * the last block flush, because compression would have been |
| * successful. If LIT_BUFSIZE <= WSIZE, it is never too late to |
| * transform a block into a stored block. |
| */ |
| send_bits((STORED_BLOCK << 1) + eof, 3); /* send block type */ |
| // G2.compressed_len = ((G2.compressed_len + 3 + 7) & ~7L) |
| // + ((stored_len + 4) << 3); |
| copy_block(buf, (unsigned) stored_len, 1); /* with header */ |
| } else |
| if (static_lenb == opt_lenb) { |
| send_bits((STATIC_TREES << 1) + eof, 3); |
| compress_block((ct_data *) G2.static_ltree, (ct_data *) G2.static_dtree); |
| // G2.compressed_len += 3 + G2.static_len; |
| } else { |
| send_bits((DYN_TREES << 1) + eof, 3); |
| send_all_trees(G2.l_desc.max_code + 1, G2.d_desc.max_code + 1, |
| max_blindex + 1); |
| compress_block((ct_data *) G2.dyn_ltree, (ct_data *) G2.dyn_dtree); |
| // G2.compressed_len += 3 + G2.opt_len; |
| } |
| // Assert(G2.compressed_len == G1.bits_sent, "bad compressed size"); |
| init_block(); |
| |
| if (eof) { |
| bi_windup(); |
| // G2.compressed_len += 7; /* align on byte boundary */ |
| } |
| // Tracev((stderr, "\ncomprlen %lu(%lu) ", |
| // (unsigned long)G2.compressed_len >> 3, |
| // (unsigned long)G2.compressed_len - 7 * eof)); |
| |
| return; /* was "return G2.compressed_len >> 3;" */ |
| } |
| |
| /* =========================================================================== |
| * Update a hash value with the given input byte |
| * IN assertion: all calls to UPDATE_HASH are made with consecutive |
| * input characters, so that a running hash key can be computed from the |
| * previous key instead of complete recalculation each time. |
| */ |
| #define UPDATE_HASH(h, c) (h = (((h)<<H_SHIFT) ^ (c)) & HASH_MASK) |
| |
| /* =========================================================================== |
| * Same as above, but achieves better compression. We use a lazy |
| * evaluation for matches: a match is finally adopted only if there is |
| * no better match at the next window position. |
| * |
| * Processes a new input file and return its compressed length. Sets |
| * the compressed length, crc, deflate flags and internal file |
| * attributes. |
| */ |
| |
| /* Flush the current block, with given end-of-file flag. |
| * IN assertion: strstart is set to the end of the current match. */ |
| #define FLUSH_BLOCK(eof) \ |
| flush_block( \ |
| G1.block_start >= 0L \ |
| ? (char*)&G1.window[(unsigned)G1.block_start] \ |
| : (char*)NULL, \ |
| (ulg)G1.strstart - G1.block_start, \ |
| (eof) \ |
| ) |
| |
| /* Insert string s in the dictionary and set match_head to the previous head |
| * of the hash chain (the most recent string with same hash key). Return |
| * the previous length of the hash chain. |
| * IN assertion: all calls to INSERT_STRING are made with consecutive |
| * input characters and the first MIN_MATCH bytes of s are valid |
| * (except for the last MIN_MATCH-1 bytes of the input file). */ |
| #define INSERT_STRING(s, match_head) \ |
| do { \ |
| UPDATE_HASH(G1.ins_h, G1.window[(s) + MIN_MATCH-1]); \ |
| G1.prev[(s) & WMASK] = match_head = head[G1.ins_h]; \ |
| head[G1.ins_h] = (s); \ |
| } while (0) |
| |
| static NOINLINE void deflate(void) |
| { |
| IPos hash_head; /* head of hash chain */ |
| IPos prev_match; /* previous match */ |
| int flush; /* set if current block must be flushed */ |
| int match_available = 0; /* set if previous match exists */ |
| unsigned match_length = MIN_MATCH - 1; /* length of best match */ |
| |
| /* Process the input block. */ |
| while (G1.lookahead != 0) { |
| /* Insert the string window[strstart .. strstart+2] in the |
| * dictionary, and set hash_head to the head of the hash chain: |
| */ |
| INSERT_STRING(G1.strstart, hash_head); |
| |
| /* Find the longest match, discarding those <= prev_length. |
| */ |
| G1.prev_length = match_length; |
| prev_match = G1.match_start; |
| match_length = MIN_MATCH - 1; |
| |
| if (hash_head != 0 && G1.prev_length < max_lazy_match |
| && G1.strstart - hash_head <= MAX_DIST |
| ) { |
| /* To simplify the code, we prevent matches with the string |
| * of window index 0 (in particular we have to avoid a match |
| * of the string with itself at the start of the input file). |
| */ |
| match_length = longest_match(hash_head); |
| /* longest_match() sets match_start */ |
| if (match_length > G1.lookahead) |
| match_length = G1.lookahead; |
| |
| /* Ignore a length 3 match if it is too distant: */ |
| if (match_length == MIN_MATCH && G1.strstart - G1.match_start > TOO_FAR) { |
| /* If prev_match is also MIN_MATCH, G1.match_start is garbage |
| * but we will ignore the current match anyway. |
| */ |
| match_length--; |
| } |
| } |
| /* If there was a match at the previous step and the current |
| * match is not better, output the previous match: |
| */ |
| if (G1.prev_length >= MIN_MATCH && match_length <= G1.prev_length) { |
| check_match(G1.strstart - 1, prev_match, G1.prev_length); |
| flush = ct_tally(G1.strstart - 1 - prev_match, G1.prev_length - MIN_MATCH); |
| |
| /* Insert in hash table all strings up to the end of the match. |
| * strstart-1 and strstart are already inserted. |
| */ |
| G1.lookahead -= G1.prev_length - 1; |
| G1.prev_length -= 2; |
| do { |
| G1.strstart++; |
| INSERT_STRING(G1.strstart, hash_head); |
| /* strstart never exceeds WSIZE-MAX_MATCH, so there are |
| * always MIN_MATCH bytes ahead. If lookahead < MIN_MATCH |
| * these bytes are garbage, but it does not matter since the |
| * next lookahead bytes will always be emitted as literals. |
| */ |
| } while (--G1.prev_length != 0); |
| match_available = 0; |
| match_length = MIN_MATCH - 1; |
| G1.strstart++; |
| if (flush) { |
| FLUSH_BLOCK(0); |
| G1.block_start = G1.strstart; |
| } |
| } else if (match_available) { |
| /* If there was no match at the previous position, output a |
| * single literal. If there was a match but the current match |
| * is longer, truncate the previous match to a single literal. |
| */ |
| Tracevv((stderr, "%c", G1.window[G1.strstart - 1])); |
| if (ct_tally(0, G1.window[G1.strstart - 1])) { |
| FLUSH_BLOCK(0); |
| G1.block_start = G1.strstart; |
| } |
| G1.strstart++; |
| G1.lookahead--; |
| } else { |
| /* There is no previous match to compare with, wait for |
| * the next step to decide. |
| */ |
| match_available = 1; |
| G1.strstart++; |
| G1.lookahead--; |
| } |
| Assert(G1.strstart <= G1.isize && G1.lookahead <= G1.isize, "a bit too far"); |
| |
| /* Make sure that we always have enough lookahead, except |
| * at the end of the input file. We need MAX_MATCH bytes |
| * for the next match, plus MIN_MATCH bytes to insert the |
| * string following the next match. |
| */ |
| fill_window_if_needed(); |
| } |
| if (match_available) |
| ct_tally(0, G1.window[G1.strstart - 1]); |
| |
| FLUSH_BLOCK(1); /* eof */ |
| } |
| |
| /* =========================================================================== |
| * Initialize the bit string routines. |
| */ |
| static void bi_init(void) |
| { |
| //G1.bi_buf = 0; // globals are zeroed in pack_gzip() |
| //G1.bi_valid = 0; // globals are zeroed in pack_gzip() |
| //DEBUG_bits_sent(= 0L); // globals are zeroed in pack_gzip() |
| } |
| |
| /* =========================================================================== |
| * Initialize the "longest match" routines for a new file |
| */ |
| static void lm_init(unsigned *flags16p) |
| { |
| unsigned j; |
| |
| /* Initialize the hash table. */ |
| memset(head, 0, HASH_SIZE * sizeof(*head)); |
| /* prev will be initialized on the fly */ |
| |
| /* speed options for the general purpose bit flag */ |
| *flags16p |= 2; /* FAST 4, SLOW 2 */ |
| /* ??? reduce max_chain_length for binary files */ |
| |
| //G1.strstart = 0; // globals are zeroed in pack_gzip() |
| //G1.block_start = 0L; // globals are zeroed in pack_gzip() |
| |
| G1.lookahead = file_read(G1.window, |
| sizeof(int) <= 2 ? (unsigned) WSIZE : 2 * WSIZE); |
| |
| if (G1.lookahead == 0 || G1.lookahead == (unsigned) -1) { |
| G1.eofile = 1; |
| G1.lookahead = 0; |
| return; |
| } |
| //G1.eofile = 0; // globals are zeroed in pack_gzip() |
| |
| /* Make sure that we always have enough lookahead. This is important |
| * if input comes from a device such as a tty. |
| */ |
| fill_window_if_needed(); |
| |
| //G1.ins_h = 0; // globals are zeroed in pack_gzip() |
| for (j = 0; j < MIN_MATCH - 1; j++) |
| UPDATE_HASH(G1.ins_h, G1.window[j]); |
| /* If lookahead < MIN_MATCH, ins_h is garbage, but this is |
| * not important since only literal bytes will be emitted. |
| */ |
| } |
| |
| /* =========================================================================== |
| * Allocate the match buffer, initialize the various tables and save the |
| * location of the internal file attribute (ascii/binary) and method |
| * (DEFLATE/STORE). |
| * One callsite in zip() |
| */ |
| static void ct_init(void) |
| { |
| int n; /* iterates over tree elements */ |
| int length; /* length value */ |
| int code; /* code value */ |
| int dist; /* distance index */ |
| |
| // //G2.compressed_len = 0L; // globals are zeroed in pack_gzip() |
| |
| #ifdef NOT_NEEDED |
| if (G2.static_dtree[0].Len != 0) |
| return; /* ct_init already called */ |
| #endif |
| |
| /* Initialize the mapping length (0..255) -> length code (0..28) */ |
| length = 0; |
| for (code = 0; code < LENGTH_CODES - 1; code++) { |
| G2.base_length[code] = length; |
| for (n = 0; n < (1 << extra_lbits[code]); n++) { |
| G2.length_code[length++] = code; |
| } |
| } |
| Assert(length == 256, "ct_init: length != 256"); |
| /* Note that the length 255 (match length 258) can be represented |
| * in two different ways: code 284 + 5 bits or code 285, so we |
| * overwrite length_code[255] to use the best encoding: |
| */ |
| G2.length_code[length - 1] = code; |
| |
| /* Initialize the mapping dist (0..32K) -> dist code (0..29) */ |
| dist = 0; |
| for (code = 0; code < 16; code++) { |
| G2.base_dist[code] = dist; |
| for (n = 0; n < (1 << extra_dbits[code]); n++) { |
| G2.dist_code[dist++] = code; |
| } |
| } |
| Assert(dist == 256, "ct_init: dist != 256"); |
| dist >>= 7; /* from now on, all distances are divided by 128 */ |
| for (; code < D_CODES; code++) { |
| G2.base_dist[code] = dist << 7; |
| for (n = 0; n < (1 << (extra_dbits[code] - 7)); n++) { |
| G2.dist_code[256 + dist++] = code; |
| } |
| } |
| Assert(dist == 256, "ct_init: 256+dist != 512"); |
| |
| /* Construct the codes of the static literal tree */ |
| //for (n = 0; n <= MAX_BITS; n++) // globals are zeroed in pack_gzip() |
| // G2.bl_count[n] = 0; |
| |
| n = 0; |
| while (n <= 143) { |
| G2.static_ltree[n++].Len = 8; |
| //G2.bl_count[8]++; |
| } |
| //G2.bl_count[8] = 143 + 1; |
| while (n <= 255) { |
| G2.static_ltree[n++].Len = 9; |
| //G2.bl_count[9]++; |
| } |
| //G2.bl_count[9] = 255 - 143; |
| while (n <= 279) { |
| G2.static_ltree[n++].Len = 7; |
| //G2.bl_count[7]++; |
| } |
| //G2.bl_count[7] = 279 - 255; |
| while (n <= 287) { |
| G2.static_ltree[n++].Len = 8; |
| //G2.bl_count[8]++; |
| } |
| //G2.bl_count[8] += 287 - 279; |
| G2.bl_count[7] = 279 - 255; |
| G2.bl_count[8] = (143 + 1) + (287 - 279); |
| G2.bl_count[9] = 255 - 143; |
| /* Codes 286 and 287 do not exist, but we must include them in the |
| * tree construction to get a canonical Huffman tree (longest code |
| * all ones) |
| */ |
| gen_codes((ct_data *) G2.static_ltree, L_CODES + 1); |
| |
| /* The static distance tree is trivial: */ |
| for (n = 0; n < D_CODES; n++) { |
| G2.static_dtree[n].Len = 5; |
| G2.static_dtree[n].Code = bi_reverse(n, 5); |
| } |
| |
| /* Initialize the first block of the first file: */ |
| init_block(); |
| } |
| |
| /* =========================================================================== |
| * Deflate in to out. |
| * IN assertions: the input and output buffers are cleared. |
| */ |
| static void zip(void) |
| { |
| unsigned deflate_flags; |
| |
| //G1.outcnt = 0; // globals are zeroed in pack_gzip() |
| |
| /* Write the header to the gzip file. See algorithm.doc for the format */ |
| /* magic header for gzip files: 1F 8B */ |
| /* compression method: 8 (DEFLATED) */ |
| /* general flags: 0 */ |
| put_32bit(0x00088b1f); |
| put_32bit(0); /* Unix timestamp */ |
| |
| /* Write deflated file to zip file */ |
| G1.crc = ~0; |
| |
| bi_init(); |
| ct_init(); |
| deflate_flags = 0; /* pkzip -es, -en or -ex equivalent */ |
| lm_init(&deflate_flags); |
| |
| put_16bit(deflate_flags | 0x300); /* extra flags. OS id = 3 (Unix) */ |
| |
| /* The above 32-bit misaligns outbuf (10 bytes are stored), flush it */ |
| flush_outbuf_if_32bit_optimized(); |
| |
| deflate(); |
| |
| /* Write the crc and uncompressed size */ |
| put_32bit(~G1.crc); |
| put_32bit(G1.isize); |
| |
| flush_outbuf(); |
| } |
| |
| /* ======================================================================== */ |
| static |
| IF_DESKTOP(long long) int FAST_FUNC pack_gzip(transformer_state_t *xstate UNUSED_PARAM) |
| { |
| /* Reinit G1.xxx except pointers to allocated buffers, and entire G2 */ |
| memset(&G1.crc, 0, (sizeof(G1) - offsetof(struct globals, crc)) + sizeof(G2)); |
| |
| /* Clear input and output buffers */ |
| //G1.outcnt = 0; |
| #ifdef DEBUG |
| //G1.insize = 0; |
| #endif |
| //G1.isize = 0; |
| |
| /* Reinit G2.xxx */ |
| G2.l_desc.dyn_tree = G2.dyn_ltree; |
| G2.l_desc.static_tree = G2.static_ltree; |
| G2.l_desc.extra_bits = extra_lbits; |
| G2.l_desc.extra_base = LITERALS + 1; |
| G2.l_desc.elems = L_CODES; |
| G2.l_desc.max_length = MAX_BITS; |
| //G2.l_desc.max_code = 0; |
| G2.d_desc.dyn_tree = G2.dyn_dtree; |
| G2.d_desc.static_tree = G2.static_dtree; |
| G2.d_desc.extra_bits = extra_dbits; |
| //G2.d_desc.extra_base = 0; |
| G2.d_desc.elems = D_CODES; |
| G2.d_desc.max_length = MAX_BITS; |
| //G2.d_desc.max_code = 0; |
| G2.bl_desc.dyn_tree = G2.bl_tree; |
| //G2.bl_desc.static_tree = NULL; |
| G2.bl_desc.extra_bits = extra_blbits, |
| //G2.bl_desc.extra_base = 0; |
| G2.bl_desc.elems = BL_CODES; |
| G2.bl_desc.max_length = MAX_BL_BITS; |
| //G2.bl_desc.max_code = 0; |
| |
| #if 0 |
| /* Saving of timestamp is disabled. Why? |
| * - it is not Y2038-safe. |
| * - some people want deterministic results |
| * (normally they'd use -n, but our -n is a nop). |
| * - it's bloat. |
| * Per RFC 1952, gzfile.time=0 is "no timestamp". |
| * If users will demand this to be reinstated, |
| * implement -n "don't save timestamp". |
| */ |
| struct stat s; |
| s.st_ctime = 0; |
| fstat(STDIN_FILENO, &s); |
| zip(s.st_ctime); |
| #else |
| zip(); |
| #endif |
| return 0; |
| } |
| |
| #if ENABLE_FEATURE_GZIP_LONG_OPTIONS |
| static const char gzip_longopts[] ALIGN1 = |
| "stdout\0" No_argument "c" |
| "to-stdout\0" No_argument "c" |
| "force\0" No_argument "f" |
| "verbose\0" No_argument "v" |
| #if ENABLE_FEATURE_GZIP_DECOMPRESS |
| "decompress\0" No_argument "d" |
| "uncompress\0" No_argument "d" |
| "test\0" No_argument "t" |
| #endif |
| "quiet\0" No_argument "q" |
| "fast\0" No_argument "1" |
| "best\0" No_argument "9" |
| "no-name\0" No_argument "n" |
| ; |
| #endif |
| |
| /* |
| * Linux kernel build uses gzip -d -n. We accept and ignore -n. |
| * Man page says: |
| * -n --no-name |
| * gzip: do not save the original file name and time stamp. |
| * (The original name is always saved if the name had to be truncated.) |
| * gunzip: do not restore the original file name/time even if present |
| * (remove only the gzip suffix from the compressed file name). |
| * This option is the default when decompressing. |
| * -N --name |
| * gzip: always save the original file name and time stamp (this is the default) |
| * gunzip: restore the original file name and time stamp if present. |
| */ |
| |
| int gzip_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
| #if ENABLE_FEATURE_GZIP_DECOMPRESS |
| int gzip_main(int argc, char **argv) |
| #else |
| int gzip_main(int argc UNUSED_PARAM, char **argv) |
| #endif |
| { |
| unsigned opt; |
| #if ENABLE_FEATURE_GZIP_LEVELS |
| static const struct { |
| uint8_t good; |
| uint8_t chain_shift; |
| uint8_t lazy2; |
| uint8_t nice2; |
| } gzip_level_config[6] = { |
| {4, 4, 4/2, 16/2}, /* Level 4 */ |
| {8, 5, 16/2, 32/2}, /* Level 5 */ |
| {8, 7, 16/2, 128/2}, /* Level 6 */ |
| {8, 8, 32/2, 128/2}, /* Level 7 */ |
| {32, 10, 128/2, 258/2}, /* Level 8 */ |
| {32, 12, 258/2, 258/2}, /* Level 9 */ |
| }; |
| #endif |
| |
| SET_PTR_TO_GLOBALS((char *)xzalloc(sizeof(struct globals)+sizeof(struct globals2)) |
| + sizeof(struct globals)); |
| |
| /* Must match bbunzip's constants OPT_STDOUT, OPT_FORCE! */ |
| #if ENABLE_FEATURE_GZIP_LONG_OPTIONS |
| opt = getopt32long(argv, BBUNPK_OPTSTR IF_FEATURE_GZIP_DECOMPRESS("dt") "n123456789", gzip_longopts); |
| #else |
| opt = getopt32(argv, BBUNPK_OPTSTR IF_FEATURE_GZIP_DECOMPRESS("dt") "n123456789"); |
| #endif |
| #if ENABLE_FEATURE_GZIP_DECOMPRESS /* gunzip_main may not be visible... */ |
| if (opt & (BBUNPK_OPT_DECOMPRESS|BBUNPK_OPT_TEST)) /* -d and/or -t */ |
| return gunzip_main(argc, argv); |
| #endif |
| #if ENABLE_FEATURE_GZIP_LEVELS |
| opt >>= (BBUNPK_OPTSTRLEN IF_FEATURE_GZIP_DECOMPRESS(+ 2) + 1); /* drop cfkvq[dt]n bits */ |
| if (opt == 0) |
| opt = 1 << 6; /* default: 6 */ |
| opt = ffs(opt >> 4); /* Maps -1..-4 to [0], -5 to [1] ... -9 to [5] */ |
| max_chain_length = 1 << gzip_level_config[opt].chain_shift; |
| good_match = gzip_level_config[opt].good; |
| max_lazy_match = gzip_level_config[opt].lazy2 * 2; |
| nice_match = gzip_level_config[opt].nice2 * 2; |
| #endif |
| option_mask32 &= BBUNPK_OPTSTRMASK; /* retain only -cfkvq */ |
| |
| /* Allocate all global buffers (for DYN_ALLOC option) */ |
| ALLOC(uch, G1.l_buf, INBUFSIZ); |
| ALLOC(uch, G1.outbuf, OUTBUFSIZ); |
| ALLOC(ush, G1.d_buf, DIST_BUFSIZE); |
| ALLOC(uch, G1.window, 2L * WSIZE); |
| ALLOC(ush, G1.prev, 1L << BITS); |
| |
| /* Initialize the CRC32 table */ |
| global_crc32_new_table_le(); |
| |
| argv += optind; |
| return bbunpack(argv, pack_gzip, append_ext, "gz"); |
| } |