/* 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. | |

*/ | |

/* big objects in bss: | |

* 00000020 b bl_count | |

* 00000074 b base_length | |

* 00000078 b base_dist | |

* 00000078 b static_dtree | |

* 0000009c b bl_tree | |

* 000000f4 b dyn_dtree | |

* 00000100 b length_code | |

* 00000200 b dist_code | |

* 0000023d b depth | |

* 00000400 b flag_buf | |

* 0000047a b heap | |

* 00000480 b static_ltree | |

* 000008f4 b dyn_ltree | |

*/ | |

/* TODO: full support for -v for DESKTOP | |

* "/usr/bin/gzip -v a bogus aa" should say: | |

a: 85.1% -- replaced with a.gz | |

gzip: bogus: No such file or directory | |

aa: 85.1% -- replaced with aa.gz | |

*/ | |

#include "libbb.h" | |

#include "unarchive.h" | |

/* =========================================================================== | |

*/ | |

//#define DEBUG 1 | |

/* Diagnostic functions */ | |

#ifdef DEBUG | |

# define Assert(cond,msg) { if (!(cond)) bb_error_msg(msg); } | |

# define Trace(x) fprintf x | |

# define Tracev(x) {if (verbose) fprintf x; } | |

# define Tracevv(x) {if (verbose > 1) fprintf x; } | |

# define Tracec(c,x) {if (verbose && (c)) fprintf x; } | |

# define Tracecv(c,x) {if (verbose > 1 && (c)) fprintf x; } | |

#else | |

# define Assert(cond,msg) | |

# define Trace(x) | |

# define Tracev(x) | |

# define Tracevv(x) | |

# define Tracec(c,x) | |

# define Tracecv(c,x) | |

#endif | |

/* =========================================================================== | |

*/ | |

#define SMALL_MEM | |

#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. | |

*/ | |

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. | |

*/ | |

}; | |

struct globals { | |

lng block_start; | |

/* window position at the beginning of the current output block. Gets | |

* negative when the window is moved backwards. | |

*/ | |

unsigned ins_h; /* hash index of string to be inserted */ | |

#define H_SHIFT ((HASH_BITS+MIN_MATCH-1) / MIN_MATCH) | |

/* Number of bits by which ins_h and del_h must be shifted at each | |

* input step. It must be such that after MIN_MATCH steps, the oldest | |

* byte no longer takes part in the hash key, that is: | |

* H_SHIFT * MIN_MATCH >= HASH_BITS | |

*/ | |

unsigned prev_length; | |

/* Length of the best match at previous step. Matches not greater than this | |

* are discarded. This is used in the lazy match evaluation. | |

*/ | |

unsigned strstart; /* start of string to insert */ | |

unsigned match_start; /* start of matching string */ | |

unsigned lookahead; /* number of valid bytes ahead in window */ | |

/* =========================================================================== | |

*/ | |

#define DECLARE(type, array, size) \ | |

type * array | |

#define ALLOC(type, array, size) \ | |

array = xzalloc((size_t)(((size)+1L)/2) * 2*sizeof(type)) | |

#define FREE(array) \ | |

do { free(array); array = NULL; } while (0) | |

/* global buffers */ | |

/* buffer for literals or lengths */ | |

/* DECLARE(uch, l_buf, LIT_BUFSIZE); */ | |

DECLARE(uch, l_buf, INBUFSIZ); | |

DECLARE(ush, d_buf, DIST_BUFSIZE); | |

DECLARE(uch, outbuf, OUTBUFSIZ); | |

/* Sliding window. Input bytes are read into the second half of the window, | |

* and move to the first half later to keep a dictionary of at least WSIZE | |

* bytes. With this organization, matches are limited to a distance of | |

* WSIZE-MAX_MATCH bytes, but this ensures that IO is always | |

* performed with a length multiple of the block size. Also, it limits | |

* the window size to 64K, which is quite useful on MSDOS. | |

* To do: limit the window size to WSIZE+BSZ if SMALL_MEM (the code would | |

* be less efficient). | |

*/ | |

DECLARE(uch, window, 2L * WSIZE); | |

/* Link to older string with same hash index. To limit the size of this | |

* array to 64K, this link is maintained only for the last 32K strings. | |

* An index in this array is thus a window index modulo 32K. | |

*/ | |

/* DECLARE(Pos, prev, WSIZE); */ | |

DECLARE(ush, prev, 1L << BITS); | |

/* Heads of the hash chains or 0. */ | |

/* DECLARE(Pos, head, 1<<HASH_BITS); */ | |

#define head (G1.prev + WSIZE) /* hash head (see deflate.c) */ | |

/* number of input bytes */ | |

ulg isize; /* only 32 bits stored in .gz file */ | |

/* bbox always use stdin/stdout */ | |

#define ifd STDIN_FILENO /* input file descriptor */ | |

#define ofd STDOUT_FILENO /* output file descriptor */ | |

#ifdef DEBUG | |

unsigned insize; /* valid bytes in l_buf */ | |

#endif | |

unsigned outcnt; /* bytes in output buffer */ | |

smallint eofile; /* flag set at end of input file */ | |

/* =========================================================================== | |

* Local data used by the "bit string" routines. | |

*/ | |

unsigned short bi_buf; | |

/* Output buffer. bits are inserted starting at the bottom (least significant | |

* bits). | |

*/ | |

#undef BUF_SIZE | |

#define BUF_SIZE (8 * sizeof(G1.bi_buf)) | |

/* Number of bits used within bi_buf. (bi_buf might be implemented on | |

* more than 16 bits on some systems.) | |

*/ | |

int bi_valid; | |

/* Current input function. Set to mem_read for in-memory compression */ | |

#ifdef DEBUG | |

ulg bits_sent; /* bit length of the compressed data */ | |

#endif | |

uint32_t *crc_32_tab; | |

uint32_t crc; /* shift register contents */ | |

}; | |

#define G1 (*(ptr_to_globals - 1)) | |

/* =========================================================================== | |

* Write the output buffer outbuf[0..outcnt-1] and update bytes_out. | |

* (used for the compressed data only) | |

*/ | |

static void flush_outbuf(void) | |

{ | |

if (G1.outcnt == 0) | |

return; | |

xwrite(ofd, (char *) G1.outbuf, G1.outcnt); | |

G1.outcnt = 0; | |

} | |

/* =========================================================================== | |

*/ | |

/* put_8bit is used for the compressed output */ | |

#define put_8bit(c) \ | |

do { \ | |

G1.outbuf[G1.outcnt++] = (c); \ | |

if (G1.outcnt == OUTBUFSIZ) flush_outbuf(); \ | |

} while (0) | |

/* Output a 16 bit value, lsb first */ | |

static void put_16bit(ush w) | |

{ | |

if (G1.outcnt < OUTBUFSIZ - 2) { | |

G1.outbuf[G1.outcnt++] = w; | |

G1.outbuf[G1.outcnt++] = w >> 8; | |

} else { | |

put_8bit(w); | |

put_8bit(w >> 8); | |

} | |

} | |

static void put_32bit(ulg n) | |

{ | |

put_16bit(n); | |

put_16bit(n >> 16); | |

} | |

/* =========================================================================== | |

* Run a set of bytes through the crc shift register. If s is a NULL | |

* pointer, then initialize the crc shift register contents instead. | |

* Return the current crc in either case. | |

*/ | |

static uint32_t updcrc(uch * s, unsigned n) | |

{ | |

uint32_t c = G1.crc; | |

while (n) { | |

c = G1.crc_32_tab[(uch)(c ^ *s++)] ^ (c >> 8); | |

n--; | |

} | |

G1.crc = c; | |

return c; | |

} | |

/* =========================================================================== | |

* Read a new buffer from the current input file, perform end-of-line | |

* translation, and update the crc and input file size. | |

* IN assertion: size >= 2 (for end-of-line translation) | |

*/ | |

static unsigned file_read(void *buf, unsigned size) | |

{ | |

unsigned len; | |

Assert(G1.insize == 0, "l_buf not empty"); | |

len = safe_read(ifd, buf, size); | |

if (len == (unsigned)(-1) || len == 0) | |

return len; | |

updcrc(buf, len); | |

G1.isize += len; | |

return len; | |

} | |

/* =========================================================================== | |

* Send a value on a given number of bits. | |

* IN assertion: length <= 16 and value fits in length bits. | |

*/ | |

static void send_bits(int value, int length) | |

{ | |

#ifdef DEBUG | |

Tracev((stderr, " l %2d v %4x ", length, value)); | |

Assert(length > 0 && length <= 15, "invalid length"); | |

G1.bits_sent += length; | |

#endif | |

/* If not enough room in bi_buf, use (valid) bits from bi_buf and | |

* (16 - bi_valid) bits from value, leaving (width - (16-bi_valid)) | |

* unused bits in value. | |

*/ | |

if (G1.bi_valid > (int) BUF_SIZE - length) { | |

G1.bi_buf |= (value << G1.bi_valid); | |

put_16bit(G1.bi_buf); | |

G1.bi_buf = (ush) value >> (BUF_SIZE - G1.bi_valid); | |

G1.bi_valid += length - BUF_SIZE; | |

} else { | |

G1.bi_buf |= value << G1.bi_valid; | |

G1.bi_valid += length; | |

} | |

} | |

/* =========================================================================== | |

* Reverse the first len bits of a code, using straightforward code (a faster | |

* method would use a table) | |

* IN assertion: 1 <= len <= 15 | |

*/ | |

static unsigned bi_reverse(unsigned code, int len) | |

{ | |

unsigned res = 0; | |

while (1) { | |

res |= code & 1; | |

if (--len <= 0) return res; | |

code >>= 1; | |

res <<= 1; | |

} | |

} | |

/* =========================================================================== | |

* Write out any remaining bits in an incomplete byte. | |

*/ | |

static void bi_windup(void) | |

{ | |

if (G1.bi_valid > 8) { | |

put_16bit(G1.bi_buf); | |

} else if (G1.bi_valid > 0) { | |

put_8bit(G1.bi_buf); | |

} | |

G1.bi_buf = 0; | |

G1.bi_valid = 0; | |

#ifdef DEBUG | |

G1.bits_sent = (G1.bits_sent + 7) & ~7; | |

#endif | |

} | |

/* =========================================================================== | |

* Copy a stored block to the zip file, storing first the length and its | |

* one's complement if requested. | |

*/ | |

static void copy_block(char *buf, unsigned len, int header) | |

{ | |

bi_windup(); /* align on byte boundary */ | |

if (header) { | |

put_16bit(len); | |

put_16bit(~len); | |

#ifdef DEBUG | |

G1.bits_sent += 2 * 16; | |

#endif | |

} | |

#ifdef DEBUG | |

G1.bits_sent += (ulg) len << 3; | |

#endif | |

while (len--) { | |

put_8bit(*buf++); | |

} | |

} | |

/* =========================================================================== | |

* Fill the window when the lookahead becomes insufficient. | |

* Updates strstart and lookahead, and sets eofile if end of input file. | |

* IN assertion: lookahead < MIN_LOOKAHEAD && strstart + lookahead > 0 | |

* OUT assertions: at least one byte has been read, or eofile is set; | |

* file reads are performed for at least two bytes (required for the | |

* translate_eol option). | |

*/ | |

static void fill_window(void) | |

{ | |

unsigned n, m; | |

unsigned more = WINDOW_SIZE - G1.lookahead - G1.strstart; | |

/* Amount of free space at the end of the window. */ | |

/* If the window is almost full and there is insufficient lookahead, | |

* move the upper half to the lower one to make room in the upper half. | |

*/ | |

if (more == (unsigned) -1) { | |

/* Very unlikely, but possible on 16 bit machine if strstart == 0 | |

* and lookahead == 1 (input done one byte at time) | |

*/ | |

more--; | |

} else if (G1.strstart >= WSIZE + MAX_DIST) { | |

/* By the IN assertion, the window is not empty so we can't confuse | |

* more == 0 with more == 64K on a 16 bit machine. | |

*/ | |

Assert(WINDOW_SIZE == 2 * WSIZE, "no sliding with BIG_MEM"); | |

memcpy(G1.window, G1.window + WSIZE, WSIZE); | |

G1.match_start -= WSIZE; | |

G1.strstart -= WSIZE; /* we now have strstart >= MAX_DIST: */ | |

G1.block_start -= WSIZE; | |

for (n = 0; n < HASH_SIZE; n++) { | |

m = head[n]; | |

head[n] = (Pos) (m >= WSIZE ? m - WSIZE : 0); | |

} | |

for (n = 0; n < WSIZE; n++) { | |

m = G1.prev[n]; | |

G1.prev[n] = (Pos) (m >= WSIZE ? m - WSIZE : 0); | |

/* If n is not on any hash chain, prev[n] is garbage but | |

* its value will never be used. | |

*/ | |

} | |

more += WSIZE; | |

} | |

/* At this point, more >= 2 */ | |

if (!G1.eofile) { | |

n = file_read(G1.window + G1.strstart + G1.lookahead, more); | |

if (n == 0 || n == (unsigned) -1) { | |

G1.eofile = 1; | |

} else { | |

G1.lookahead += n; | |

} | |

} | |

} | |

/* =========================================================================== | |

* Set match_start to the longest match starting at the given string and | |

* return its length. Matches shorter or equal to prev_length are discarded, | |

* in which case the result is equal to prev_length and match_start is | |

* garbage. | |

* IN assertions: cur_match is the head of the hash chain for the current | |

* string (strstart) and its distance is <= MAX_DIST, and prev_length >= 1 | |

*/ | |

/* For MSDOS, OS/2 and 386 Unix, an optimized version is in match.asm or | |

* match.s. The code is functionally equivalent, so you can use the C version | |

* if desired. | |

*/ | |

static int longest_match(IPos cur_match) | |

{ | |

unsigned chain_length = max_chain_length; /* max hash chain length */ | |

uch *scan = G1.window + G1.strstart; /* current string */ | |

uch *match; /* matched string */ | |

int len; /* length of current match */ | |

int best_len = G1.prev_length; /* best match length so far */ | |

IPos limit = G1.strstart > (IPos) MAX_DIST ? G1.strstart - (IPos) MAX_DIST : 0; | |

/* Stop when cur_match becomes <= limit. To simplify the code, | |

* we prevent matches with the string of window index 0. | |

*/ | |

/* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16. | |

* It is easy to get rid of this optimization if necessary. | |

*/ | |

#if HASH_BITS < 8 || MAX_MATCH != 258 | |

# error Code too clever | |

#endif | |

uch *strend = G1.window + G1.strstart + MAX_MATCH; | |

uch scan_end1 = scan[best_len - 1]; | |

uch scan_end = scan[best_len]; | |

/* Do not waste too much time if we already have a good match: */ | |

if (G1.prev_length >= good_match) { | |

chain_length >>= 2; | |

} | |

Assert(G1.strstart <= WINDOW_SIZE - MIN_LOOKAHEAD, "insufficient lookahead"); | |

do { | |

Assert(cur_match < G1.strstart, "no future"); | |

match = G1.window + cur_match; | |

/* Skip to next match if the match length cannot increase | |

* or if the match length is less than 2: | |

*/ | |

if (match[best_len] != scan_end | |

|| match[best_len - 1] != scan_end1 | |

|| *match != *scan || *++match != scan[1] | |

) { | |

continue; | |

} | |

/* The check at best_len-1 can be removed because it will be made | |

* again later. (This heuristic is not always a win.) | |

* It is not necessary to compare scan[2] and match[2] since they | |

* are always equal when the other bytes match, given that | |

* the hash keys are equal and that HASH_BITS >= 8. | |

*/ | |

scan += 2, match++; | |

/* We check for insufficient lookahead only every 8th comparison; | |

* the 256th check will be made at strstart+258. | |

*/ | |

do { | |

} while (*++scan == *++match && *++scan == *++match && | |

*++scan == *++match && *++scan == *++match && | |

*++scan == *++match && *++scan == *++match && | |

*++scan == *++match && *++scan == *++match && scan < strend); | |

len = MAX_MATCH - (int) (strend - scan); | |

scan = strend - MAX_MATCH; | |

if (len > best_len) { | |

G1.match_start = cur_match; | |

best_len = len; | |

if (len >= nice_match) | |

break; | |

scan_end1 = scan[best_len - 1]; | |

scan_end = scan[best_len]; | |

} | |

} while ((cur_match = G1.prev[cur_match & WMASK]) > limit | |

&& --chain_length != 0); | |

return best_len; | |

} | |

#ifdef DEBUG | |

/* =========================================================================== | |

* Check that the match at match_start is indeed a match. | |

*/ | |

static void check_match(IPos start, IPos match, int length) | |

{ | |

/* check that the match is indeed a match */ | |

if (memcmp(G1.window + match, G1.window + start, length) != 0) { | |

bb_error_msg(" start %d, match %d, length %d", start, match, length); | |

bb_error_msg("invalid match"); | |

} | |

if (verbose > 1) { | |

bb_error_msg("\\[%d,%d]", start - match, length); | |

do { | |

bb_putchar_stderr(G1.window[start++]); | |

} while (--length != 0); | |

} | |

} | |

#else | |

# define check_match(start, match, length) ((void)0) | |

#endif | |

/* trees.c -- output deflated data using Huffman coding | |

* Copyright (C) 1992-1993 Jean-loup Gailly | |

* This is free software; you can redistribute it and/or modify it under the | |

* terms of the GNU General Public License, see the file COPYING. | |

*/ | |

/* PURPOSE | |

* Encode various sets of source values using variable-length | |

* binary code trees. | |

* | |

* DISCUSSION | |

* The PKZIP "deflation" process uses several Huffman trees. The more | |

* common source values are represented by shorter bit sequences. | |

* | |

* Each code tree is stored in the ZIP file in a compressed form | |

* which is itself a Huffman encoding of the lengths of | |

* all the code strings (in ascending order by source values). | |

* The actual code strings are reconstructed from the lengths in | |

* the UNZIP process, as described in the "application note" | |

* (APPNOTE.TXT) distributed as part of PKWARE's PKZIP program. | |

* | |

* REFERENCES | |

* Lynch, Thomas J. | |

* Data Compression: Techniques and Applications, pp. 53-55. | |

* Lifetime Learning Publications, 1985. ISBN 0-534-03418-7. | |

* | |

* Storer, James A. | |

* Data Compression: Methods and Theory, pp. 49-50. | |

* Computer Science Press, 1988. ISBN 0-7167-8156-5. | |

* | |

* Sedgewick, R. | |

* Algorithms, p290. | |

* Addison-Wesley, 1983. ISBN 0-201-06672-6. | |

* | |

* INTERFACE | |

* void ct_init() | |

* Allocate the match buffer, initialize the various tables [and save | |

* the location of the internal file attribute (ascii/binary) and | |

* method (DEFLATE/STORE) -- deleted in bbox] | |

* | |

* void ct_tally(int dist, int lc); | |

* Save the match info and tally the frequency counts. | |

* | |

* ulg flush_block(char *buf, ulg stored_len, int eof) | |

* Determine the best encoding for the current block: dynamic trees, | |

* static trees or store, and output the encoded block to the zip | |

* file. Returns the total compressed length for the file so far. | |

*/ | |

#define MAX_BITS 15 | |

/* All codes must not exceed MAX_BITS bits */ | |

#define MAX_BL_BITS 7 | |

/* Bit length codes must not exceed MAX_BL_BITS bits */ | |

#define LENGTH_CODES 29 | |

/* number of length codes, not counting the special END_BLOCK code */ | |

#define LITERALS 256 | |

/* number of literal bytes 0..255 */ | |

#define END_BLOCK 256 | |

/* end of block literal code */ | |

#define L_CODES (LITERALS+1+LENGTH_CODES) | |

/* number of Literal or Length codes, including the END_BLOCK code */ | |

#define D_CODES 30 | |

/* number of distance codes */ | |

#define BL_CODES 19 | |

/* number of codes used to transfer the bit lengths */ | |

/* extra bits for each length code */ | |

static const uint8_t extra_lbits[LENGTH_CODES] ALIGN1 = { | |

0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4, | |

4, 4, 5, 5, 5, 5, 0 | |

}; | |

/* extra bits for each distance code */ | |

static const uint8_t extra_dbits[D_CODES] ALIGN1 = { | |

0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6, 7, 7, 8, 8, 9, 9, | |

10, 10, 11, 11, 12, 12, 13, 13 | |

}; | |

/* extra bits for each bit length code */ | |

static const uint8_t extra_blbits[BL_CODES] ALIGN1 = { | |

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 3, 7 }; | |

/* number of codes at each bit length for an optimal tree */ | |

static const uint8_t bl_order[BL_CODES] ALIGN1 = { | |

16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15 }; | |

#define STORED_BLOCK 0 | |

#define STATIC_TREES 1 | |

#define DYN_TREES 2 | |

/* The three kinds of block type */ | |

#ifndef LIT_BUFSIZE | |

# ifdef SMALL_MEM | |

# define LIT_BUFSIZE 0x2000 | |

# else | |

# ifdef MEDIUM_MEM | |

# define LIT_BUFSIZE 0x4000 | |

# else | |

# define LIT_BUFSIZE 0x8000 | |

# endif | |

# endif | |

#endif | |

#ifndef DIST_BUFSIZE | |

# define DIST_BUFSIZE LIT_BUFSIZE | |

#endif | |

/* Sizes of match buffers for literals/lengths and distances. There are | |

* 4 reasons for limiting LIT_BUFSIZE to 64K: | |

* - frequencies can be kept in 16 bit counters | |

* - if compression is not successful for the first block, all input data is | |

* still in the window so we can still emit a stored block even when input | |

* comes from standard input. (This can also be done for all blocks if | |

* LIT_BUFSIZE is not greater than 32K.) | |

* - if compression is not successful for a file smaller than 64K, we can | |

* even emit a stored file instead of a stored block (saving 5 bytes). | |

* - creating new Huffman trees less frequently may not provide fast | |

* adaptation to changes in the input data statistics. (Take for | |

* example a binary file with poorly compressible code followed by | |

* a highly compressible string table.) Smaller buffer sizes give | |

* fast adaptation but have of course the overhead of transmitting trees | |

* more frequently. | |

* - I can't count above 4 | |

* The current code is general and allows DIST_BUFSIZE < LIT_BUFSIZE (to save | |

* memory at the expense of compression). Some optimizations would be possible | |

* if we rely on DIST_BUFSIZE == LIT_BUFSIZE. | |

*/ | |

#define REP_3_6 16 | |

/* repeat previous bit length 3-6 times (2 bits of repeat count) */ | |

#define REPZ_3_10 17 | |

/* repeat a zero length 3-10 times (3 bits of repeat count) */ | |

#define REPZ_11_138 18 | |

/* repeat a zero length 11-138 times (7 bits of repeat count) */ | |

/* =========================================================================== | |

*/ | |

/* Data structure describing a single value and its code string. */ | |

typedef struct ct_data { | |

union { | |

ush freq; /* frequency count */ | |

ush code; /* bit string */ | |

} fc; | |

union { | |

ush dad; /* father node in Huffman tree */ | |

ush len; /* length of bit string */ | |

} dl; | |

} ct_data; | |

#define Freq fc.freq | |

#define Code fc.code | |

#define Dad dl.dad | |

#define Len dl.len | |

#define HEAP_SIZE (2*L_CODES + 1) | |

/* maximum heap size */ | |

typedef struct tree_desc { | |

ct_data *dyn_tree; /* the dynamic tree */ | |

ct_data *static_tree; /* corresponding static tree or NULL */ | |

const uint8_t *extra_bits; /* extra bits for each code or NULL */ | |

int extra_base; /* base index for extra_bits */ | |

int elems; /* max number of elements in the tree */ | |

int max_length; /* max bit length for the codes */ | |

int max_code; /* largest code with non zero frequency */ | |

} tree_desc; | |

struct globals2 { | |

ush heap[HEAP_SIZE]; /* heap used to build the Huffman trees */ | |

int heap_len; /* number of elements in the heap */ | |

int heap_max; /* element of largest frequency */ | |

/* The sons of heap[n] are heap[2*n] and heap[2*n+1]. heap[0] is not used. | |

* The same heap array is used to build all trees. | |

*/ | |

ct_data dyn_ltree[HEAP_SIZE]; /* literal and length tree */ | |

ct_data dyn_dtree[2 * D_CODES + 1]; /* distance tree */ | |

ct_data static_ltree[L_CODES + 2]; | |

/* The static literal tree. Since the bit lengths are imposed, there is no | |

* need for the L_CODES extra codes used during heap construction. However | |

* The codes 286 and 287 are needed to build a canonical tree (see ct_init | |

* below). | |

*/ | |

ct_data static_dtree[D_CODES]; | |

/* The static distance tree. (Actually a trivial tree since all codes use | |

* 5 bits.) | |

*/ | |

ct_data bl_tree[2 * BL_CODES + 1]; | |

/* Huffman tree for the bit lengths */ | |

tree_desc l_desc; | |

tree_desc d_desc; | |

tree_desc bl_desc; | |

ush bl_count[MAX_BITS + 1]; | |

/* The lengths of the bit length codes are sent in order of decreasing | |

* probability, to avoid transmitting the lengths for unused bit length codes. | |

*/ | |

uch depth[2 * L_CODES + 1]; | |

/* Depth of each subtree used as tie breaker for trees of equal frequency */ | |

uch length_code[MAX_MATCH - MIN_MATCH + 1]; | |

/* length code for each normalized match length (0 == MIN_MATCH) */ | |

uch dist_code[512]; | |

/* distance codes. The first 256 values correspond to the distances | |

* 3 .. 258, the last 256 values correspond to the top 8 bits of | |

* the 15 bit distances. | |

*/ | |

int base_length[LENGTH_CODES]; | |

/* First normalized length for each code (0 = MIN_MATCH) */ | |

int base_dist[D_CODES]; | |

/* First normalized distance for each code (0 = distance of 1) */ | |

uch flag_buf[LIT_BUFSIZE / 8]; | |

/* flag_buf is a bit array distinguishing literals from lengths in | |

* l_buf, thus indicating the presence or absence of a distance. | |

*/ | |

unsigned last_lit; /* running index in l_buf */ | |

unsigned last_dist; /* running index in d_buf */ | |

unsigned last_flags; /* running index in flag_buf */ | |

uch flags; /* current flags not yet saved in flag_buf */ | |

uch flag_bit; /* current bit used in flags */ | |

/* bits are filled in flags starting at bit 0 (least significant). | |

* Note: these flags are overkill in the current code since we don't | |

* take advantage of DIST_BUFSIZE == LIT_BUFSIZE. | |

*/ | |

ulg opt_len; /* bit length of current block with optimal trees */ | |

ulg static_len; /* bit length of current block with static trees */ | |

ulg compressed_len; /* total bit length of compressed file */ | |

}; | |

#define G2ptr ((struct globals2*)(ptr_to_globals)) | |

#define G2 (*G2ptr) | |

/* =========================================================================== | |

*/ | |

static void gen_codes(ct_data * tree, int max_code); | |

static void build_tree(tree_desc * desc); | |

static void scan_tree(ct_data * tree, int max_code); | |

static void send_tree(ct_data * tree, int max_code); | |

static int build_bl_tree(void); | |

static void send_all_trees(int lcodes, int dcodes, int blcodes); | |

static void compress_block(ct_data * ltree, ct_data * dtree); | |

#ifndef DEBUG | |

/* Send a code of the given tree. c and tree must not have side effects */ | |

# define SEND_CODE(c, tree) send_bits(tree[c].Code, tree[c].Len) | |

#else | |

# define SEND_CODE(c, tree) \ | |

{ \ | |

if (verbose > 1) bb_error_msg("\ncd %3d ", (c)); \ | |

send_bits(tree[c].Code, tree[c].Len); \ | |

} | |

#endif | |

#define D_CODE(dist) \ | |

((dist) < 256 ? G2.dist_code[dist] : G2.dist_code[256 + ((dist)>>7)]) | |

/* Mapping from a distance to a distance code. dist is the distance - 1 and | |

* must not have side effects. dist_code[256] and dist_code[257] are never | |

* used. | |

* The arguments must not have side effects. | |

*/ | |

/* =========================================================================== | |

* Initialize a new block. | |

*/ | |

static void init_block(void) | |

{ | |

int n; /* iterates over tree elements */ | |

/* Initialize the trees. */ | |

for (n = 0; n < L_CODES; n++) | |

G2.dyn_ltree[n].Freq = 0; | |

for (n = 0; n < D_CODES; n++) | |

G2.dyn_dtree[n].Freq = 0; | |

for (n = 0; n < BL_CODES; n++) | |

G2.bl_tree[n].Freq = 0; | |

G2.dyn_ltree[END_BLOCK].Freq = 1; | |

G2.opt_len = G2.static_len = 0; | |

G2.last_lit = G2.last_dist = G2.last_flags = 0; | |

G2.flags = 0; | |

G2.flag_bit = 1; | |

} | |

/* =========================================================================== | |

* Restore the heap property by moving down the tree starting at node k, | |

* exchanging a node with the smallest of its two sons if necessary, stopping | |

* when the heap property is re-established (each father smaller than its | |

* two sons). | |

*/ | |

/* Compares to subtrees, using the tree depth as tie breaker when | |

* the subtrees have equal frequency. This minimizes the worst case length. */ | |

#define SMALLER(tree, n, m) \ | |

(tree[n].Freq < tree[m].Freq \ | |

|| (tree[n].Freq == tree[m].Freq && G2.depth[n] <= G2.depth[m])) | |

static void pqdownheap(ct_data * tree, int k) | |

{ | |

int v = G2.heap[k]; | |

int j = k << 1; /* left son of k */ | |

while (j <= G2.heap_len) { | |

/* Set j to the smallest of the two sons: */ | |

if (j < G2.heap_len && SMALLER(tree, G2.heap[j + 1], G2.heap[j])) | |

j++; | |

/* Exit if v is smaller than both sons */ | |

if (SMALLER(tree, v, G2.heap[j])) | |

break; | |

/* Exchange v with the smallest son */ | |

G2.heap[k] = G2.heap[j]; | |

k = j; | |

/* And continue down the tree, setting j to the left son of k */ | |

j <<= 1; | |

} | |

G2.heap[k] = v; | |

} | |

/* =========================================================================== | |

* Compute the optimal bit lengths for a tree and update the total bit length | |

* for the current block. | |

* IN assertion: the fields freq and dad are set, heap[heap_max] and | |

* above are the tree nodes sorted by increasing frequency. | |

* OUT assertions: the field len is set to the optimal bit length, the | |

* array bl_count contains the frequencies for each bit length. | |

* The length opt_len is updated; static_len is also updated if stree is | |

* not null. | |

*/ | |

static void gen_bitlen(tree_desc * desc) | |

{ | |

ct_data *tree = desc->dyn_tree; | |

const uint8_t *extra = desc->extra_bits; | |

int base = desc->extra_base; | |

int max_code = desc->max_code; | |

int max_length = desc->max_length; | |

ct_data *stree = desc->static_tree; | |

int h; /* heap index */ | |

int n, m; /* iterate over the tree elements */ | |

int bits; /* bit length */ | |

int xbits; /* extra bits */ | |

ush f; /* frequency */ | |

int overflow = 0; /* number of elements with bit length too large */ | |

for (bits = 0; bits <= MAX_BITS; bits++) | |

G2.bl_count[bits] = 0; | |

/* In a first pass, compute the optimal bit lengths (which may | |

* overflow in the case of the bit length tree). | |

*/ | |

tree[G2.heap[G2.heap_max]].Len = 0; /* root of the heap */ | |

for (h = G2.heap_max + 1; h < HEAP_SIZE; h++) { | |

n = G2.heap[h]; | |

bits = tree[tree[n].Dad].Len + 1; | |

if (bits > max_length) { | |

bits = max_length; | |

overflow++; | |

} | |

tree[n].Len = (ush) bits; | |

/* We overwrite tree[n].Dad which is no longer needed */ | |

if (n > max_code) | |

continue; /* not a leaf node */ | |

G2.bl_count[bits]++; | |

xbits = 0; | |

if (n >= base) | |

xbits = extra[n - base]; | |

f = tree[n].Freq; | |

G2.opt_len += (ulg) f *(bits + xbits); | |

if (stree) | |

G2.static_len += (ulg) f * (stree[n].Len + xbits); | |

} | |

if (overflow == 0) | |

return; | |

Trace((stderr, "\nbit length overflow\n")); | |

/* This happens for example on obj2 and pic of the Calgary corpus */ | |

/* Find the first bit length which could increase: */ | |

do { | |

bits = max_length - 1; | |

while (G2.bl_count[bits] == 0) | |

bits--; | |

G2.bl_count[bits]--; /* move one leaf down the tree */ | |

G2.bl_count[bits + 1] += 2; /* move one overflow item as its brother */ | |

G2.bl_count[max_length]--; | |

/* The brother of the overflow item also moves one step up, | |

* but this does not affect bl_count[max_length] | |

*/ | |

overflow -= 2; | |

} while (overflow > 0); | |

/* Now recompute all bit lengths, scanning in increasing frequency. | |

* h is still equal to HEAP_SIZE. (It is simpler to reconstruct all | |

* lengths instead of fixing only the wrong ones. This idea is taken | |

* from 'ar' written by Haruhiko Okumura.) | |

*/ | |

for (bits = max_length; bits != 0; bits--) { | |

n = G2.bl_count[bits]; | |

while (n != 0) { | |

m = G2.heap[--h]; | |

if (m > max_code) | |

continue; | |

if (tree[m].Len != (unsigned) bits) { | |

Trace((stderr, "code %d bits %d->%d\n", m, tree[m].Len, bits)); | |

G2.opt_len += ((int32_t) bits - tree[m].Len) * tree[m].Freq; | |

tree[m].Len = bits; | |

} | |

n--; | |

} | |

} | |

} | |

/* =========================================================================== | |

* Generate the codes for a given tree and bit counts (which need not be | |

* optimal). | |

* IN assertion: the array bl_count contains the bit length statistics for | |

* the given tree and the field len is set for all tree elements. | |

* OUT assertion: the field code is set for all tree elements of non | |

* zero code length. | |

*/ | |

static void gen_codes(ct_data * tree, int max_code) | |

{ | |

ush next_code[MAX_BITS + 1]; /* next code value for each bit length */ | |

ush code = 0; /* running code value */ | |

int bits; /* bit index */ | |

int n; /* code index */ | |

/* The distribution counts are first used to generate the code values | |

* without bit reversal. | |

*/ | |

for (bits = 1; bits <= MAX_BITS; bits++) { | |

next_code[bits] = code = (code + G2.bl_count[bits - 1]) << 1; | |

} | |

/* Check that the bit counts in bl_count are consistent. The last code | |

* must be all ones. | |

*/ | |

Assert(code + G2.bl_count[MAX_BITS] - 1 == (1 << MAX_BITS) - 1, | |

"inconsistent bit counts"); | |

Tracev((stderr, "\ngen_codes: max_code %d ", max_code)); | |

for (n = 0; n <= max_code; n++) { | |

int len = tree[n].Len; | |

if (len == 0) | |

continue; | |

/* Now reverse the bits */ | |

tree[n].Code = bi_reverse(next_code[len]++, len); | |

Tracec(tree != G2.static_ltree, | |

(stderr, "\nn %3d %c l %2d c %4x (%x) ", n, | |

(n > ' ' ? n : ' '), len, tree[n].Code, | |

next_code[len] - 1)); | |

} | |

} | |

/* =========================================================================== | |

* Construct one Huffman tree and assigns the code bit strings and lengths. | |

* Update the total bit length for the current block. | |

* IN assertion: the field freq is set for all tree elements. | |

* OUT assertions: the fields len and code are set to the optimal bit length | |

* and corresponding code. The length opt_len is updated; static_len is | |

* also updated if stree is not null. The field max_code is set. | |

*/ | |

/* Remove the smallest element from the heap and recreate the heap with | |

* one less element. Updates heap and heap_len. */ | |

#define SMALLEST 1 | |

/* Index within the heap array of least frequent node in the Huffman tree */ | |

#define PQREMOVE(tree, top) \ | |

do { \ | |

top = G2.heap[SMALLEST]; \ | |

G2.heap[SMALLEST] = G2.heap[G2.heap_len--]; \ | |

pqdownheap(tree, SMALLEST); \ | |

} while (0) | |

static void build_tree(tree_desc * desc) | |

{ | |

ct_data *tree = desc->dyn_tree; | |

ct_data *stree = desc->static_tree; | |

int elems = desc->elems; | |

int n, m; /* iterate over heap elements */ | |

int max_code = -1; /* largest code with non zero frequency */ | |

int node = elems; /* next internal node of the tree */ | |

/* Construct the initial heap, with least frequent element in | |

* heap[SMALLEST]. The sons of heap[n] are heap[2*n] and heap[2*n+1]. | |

* heap[0] is not used. | |

*/ | |

G2.heap_len = 0; | |

G2.heap_max = HEAP_SIZE; | |

for (n = 0; n < elems; n++) { | |

if (tree[n].Freq != 0) { | |

G2.heap[++G2.heap_len] = max_code = n; | |

G2.depth[n] = 0; | |

} else { | |

tree[n].Len = 0; | |

} | |

} | |

/* The pkzip format requires that at least one distance code exists, | |

* and that at least one bit should be sent even if there is only one | |

* possible code. So to avoid special checks later on we force at least | |

* two codes of non zero frequency. | |

*/ | |

while (G2.heap_len < 2) { | |

int new = G2.heap[++G2.heap_len] = (max_code < 2 ? ++max_code : 0); | |

tree[new].Freq = 1; | |

G2.depth[new] = 0; | |

G2.opt_len--; | |

if (stree) | |

G2.static_len -= stree[new].Len; | |

/* new is 0 or 1 so it does not have extra bits */ | |

} | |

desc->max_code = max_code; | |

/* The elements heap[heap_len/2+1 .. heap_len] are leaves of the tree, | |

* establish sub-heaps of increasing lengths: | |

*/ | |

for (n = G2.heap_len / 2; n >= 1; n--) | |

pqdownheap(tree, n); | |

/* Construct the Huffman tree by repeatedly combining the least two | |

* frequent nodes. | |

*/ | |

do { | |

PQREMOVE(tree, n); /* n = node of least frequency */ | |

m = G2.heap[SMALLEST]; /* m = node of next least frequency */ | |

G2.heap[--G2.heap_max] = n; /* keep the nodes sorted by frequency */ | |

G2.heap[--G2.heap_max] = m; | |

/* Create a new node father of n and m */ | |

tree[node].Freq = tree[n].Freq + tree[m].Freq; | |

G2.depth[node] = MAX(G2.depth[n], G2.depth[m]) + 1; | |

tree[n].Dad = tree[m].Dad = (ush) node; | |

#ifdef DUMP_BL_TREE | |

if (tree == G2.bl_tree) { | |

bb_error_msg("\nnode %d(%d), sons %d(%d) %d(%d)", | |

node, tree[node].Freq, n, tree[n].Freq, m, tree[m].Freq); | |

} | |

#endif | |

/* and insert the new node in the heap */ | |

G2.heap[SMALLEST] = node++; | |

pqdownheap(tree, SMALLEST); | |

} while (G2.heap_len >= 2); | |

G2.heap[--G2.heap_max] = G2.heap[SMALLEST]; | |

/* At this point, the fields freq and dad are set. We can now | |

* generate the bit lengths. | |

*/ | |

gen_bitlen((tree_desc *) desc); | |

/* The field len is now set, we can generate the bit codes */ | |

gen_codes((ct_data *) tree, max_code); | |

} | |

/* =========================================================================== | |

* Scan a literal or distance tree to determine the frequencies of the codes | |

* in the bit length tree. Updates opt_len to take into account the repeat | |

* counts. (The contribution of the bit length codes will be added later | |

* during the construction of bl_tree.) | |

*/ | |

static void scan_tree(ct_data * tree, int max_code) | |

{ | |

int n; /* iterates over all tree elements */ | |

int prevlen = -1; /* last emitted length */ | |

int curlen; /* length of current code */ | |

int nextlen = tree[0].Len; /* length of next code */ | |

int count = 0; /* repeat count of the current code */ | |

int max_count = 7; /* max repeat count */ | |

int min_count = 4; /* min repeat count */ | |

if (nextlen == 0) { | |

max_count = 138; | |

min_count = 3; | |

} | |

tree[max_code + 1].Len = 0xffff; /* guard */ | |

for (n = 0; n <= max_code; n++) { | |

curlen = nextlen; | |

nextlen = tree[n + 1].Len; | |

if (++count < max_count && curlen == nextlen) | |

continue; | |

if (count < min_count) { | |

G2.bl_tree[curlen].Freq += count; | |

} else if (curlen != 0) { | |

if (curlen != prevlen) | |

G2.bl_tree[curlen].Freq++; | |

G2.bl_tree[REP_3_6].Freq++; | |

} else if (count <= 10) { | |

G2.bl_tree[REPZ_3_10].Freq++; | |

} else { | |

G2.bl_tree[REPZ_11_138].Freq++; | |

} | |

count = 0; | |

prevlen = curlen; | |

max_count = 7; | |

min_count = 4; | |

if (nextlen == 0) { | |

max_count = 138; | |

min_count = 3; | |

} else if (curlen == nextlen) { | |

max_count = 6; | |

min_count = 3; | |

} | |

} | |

} | |

/* =========================================================================== | |

* Send a literal or distance tree in compressed form, using the codes in | |

* bl_tree. | |

*/ | |

static void send_tree(ct_data * tree, int max_code) | |

{ | |

int n; /* iterates over all tree elements */ | |

int prevlen = -1; /* last emitted length */ | |

int curlen; /* length of current code */ | |

int nextlen = tree[0].Len; /* length of next code */ | |

int count = 0; /* repeat count of the current code */ | |

int max_count = 7; /* max repeat count */ | |

int min_count = 4; /* min repeat count */ | |

/* tree[max_code+1].Len = -1; *//* guard already set */ | |

if (nextlen == 0) | |

max_count = 138, min_count = 3; | |

for (n = 0; n <= max_code; n++) { | |

curlen = nextlen; | |

nextlen = tree[n + 1].Len; | |

if (++count < max_count && curlen == nextlen) { | |

continue; | |

} else if (count < min_count) { | |

do { | |

SEND_CODE(curlen, G2.bl_tree); | |

} while (--count); | |

} else if (curlen != 0) { | |

if (curlen != prevlen) { | |

SEND_CODE(curlen, G2.bl_tree); | |

count--; | |

} | |

Assert(count >= 3 && count <= 6, " 3_6?"); | |

SEND_CODE(REP_3_6, G2.bl_tree); | |

send_bits(count - 3, 2); | |

} else if (count <= 10) { | |

SEND_CODE(REPZ_3_10, G2.bl_tree); | |

send_bits(count - 3, 3); | |

} else { | |

SEND_CODE(REPZ_11_138, G2.bl_tree); | |

send_bits(count - 11, 7); | |

} | |

count = 0; | |

prevlen = curlen; | |

if (nextlen == 0) { | |

max_count = 138; | |

min_count = 3; | |

} else if (curlen == nextlen) { | |

max_count = 6; | |

min_count = 3; | |

} else { | |

max_count = 7; | |

min_count = 4; | |

} | |

} | |

} | |

/* =========================================================================== | |

* Construct the Huffman tree for the bit lengths and return the index in | |

* bl_order of the last bit length code to send. | |

*/ | |

static int build_bl_tree(void) | |

{ | |

int max_blindex; /* index of last bit length code of non zero freq */ | |

/* Determine the bit length frequencies for literal and distance trees */ | |

scan_tree(G2.dyn_ltree, G2.l_desc.max_code); | |

scan_tree(G2.dyn_dtree, G2.d_desc.max_code); | |

/* Build the bit length tree: */ | |

build_tree(&G2.bl_desc); | |

/* opt_len now includes the length of the tree representations, except | |

* the lengths of the bit lengths codes and the 5+5+4 bits for the counts. | |

*/ | |

/* Determine the number of bit length codes to send. The pkzip format | |

* requires that at least 4 bit length codes be sent. (appnote.txt says | |

* 3 but the actual value used is 4.) | |

*/ | |

for (max_blindex = BL_CODES - 1; max_blindex >= 3; max_blindex--) { | |

if (G2.bl_tree[bl_order[max_blindex]].Len != 0) | |

break; | |

} | |

/* Update opt_len to include the bit length tree and counts */ | |

G2.opt_len += 3 * (max_blindex + 1) + 5 + 5 + 4; | |

Tracev((stderr, "\ndyn trees: dyn %ld, stat %ld", G2.opt_len, G2.static_len)); | |

return max_blindex; | |

} | |

/* =========================================================================== | |

* Send the header for a block using dynamic Huffman trees: the counts, the | |

* lengths of the bit length codes, the literal tree and the distance tree. | |

* IN assertion: lcodes >= 257, dcodes >= 1, blcodes >= 4. | |

*/ | |

static void send_all_trees(int lcodes, int dcodes, int blcodes) | |

{ | |

int rank; /* index in bl_order */ | |

Assert(lcodes >= 257 && dcodes >= 1 && blcodes >= 4, "not enough codes"); | |

Assert(lcodes <= L_CODES && dcodes <= D_CODES | |

&& blcodes <= BL_CODES, "too many codes"); | |

Tracev((stderr, "\nbl counts: ")); | |

send_bits(lcodes - 257, 5); /* not +255 as stated in appnote.txt */ | |

send_bits(dcodes - 1, 5); | |

send_bits(blcodes - 4, 4); /* not -3 as stated in appnote.txt */ | |

for (rank = 0; rank < blcodes; rank++) { | |

Tracev((stderr, "\nbl code %2d ", bl_order[rank])); | |

send_bits(G2.bl_tree[bl_order[rank]].Len, 3); | |

} | |

Tracev((stderr, "\nbl tree: sent %ld", G1.bits_sent)); | |

send_tree((ct_data *) G2.dyn_ltree, lcodes - 1); /* send the literal tree */ | |

Tracev((stderr, "\nlit tree: sent %ld", G1.bits_sent)); | |

send_tree((ct_data *) G2.dyn_dtree, dcodes - 1); /* send the distance tree */ | |

Tracev((stderr, "\ndist tree: sent %ld", G1.bits_sent)); | |

} | |

/* =========================================================================== | |

* Save the match info and tally the frequency counts. Return true if | |

* the current block must be flushed. | |

*/ | |

static int ct_tally(int dist, int lc) | |

{ | |

G1.l_buf[G2.last_lit++] = lc; | |

if (dist == 0) { | |

/* lc is the unmatched char */ | |

G2.dyn_ltree[lc].Freq++; | |

} else { | |

/* Here, lc is the match length - MIN_MATCH */ | |

dist--; /* dist = match distance - 1 */ | |

Assert((ush) dist < (ush) MAX_DIST | |

&& (ush) lc <= (ush) (MAX_MATCH - MIN_MATCH) | |

&& (ush) D_CODE(dist) < (ush) D_CODES, "ct_tally: bad match" | |

); | |

G2.dyn_ltree[G2.length_code[lc] + LITERALS + 1].Freq++; | |

G2.dyn_dtree[D_CODE(dist)].Freq++; | |

G1.d_buf[G2.last_dist++] = dist; | |

G2.flags |= G2.flag_bit; | |

} | |

G2.flag_bit <<= 1; | |

/* Output the flags if they fill a byte: */ | |

if ((G2.last_lit & 7) == 0) { | |

G2.flag_buf[G2.last_flags++] = G2.flags; | |

G2.flags = 0; | |

G2.flag_bit = 1; | |

} | |

/* Try to guess if it is profitable to stop the current block here */ | |

if ((G2.last_lit & 0xfff) == 0) { | |

/* Compute an upper bound for the compressed length */ | |

ulg out_length = G2.last_lit * 8L; | |

ulg in_length = (ulg) G1.strstart - G1.block_start; | |

int dcode; | |

for (dcode = 0; dcode < D_CODES; dcode++) { | |

out_length += G2.dyn_dtree[dcode].Freq * (5L + extra_dbits[dcode]); | |

} | |

out_length >>= 3; | |

Trace((stderr, | |

"\nlast_lit %u, last_dist %u, in %ld, out ~%ld(%ld%%) ", | |

G2.last_lit, G2.last_dist, in_length, out_length, | |

100L - out_length * 100L / in_length)); | |

if (G2.last_dist < G2.last_lit / 2 && out_length < in_length / 2) | |

return 1; | |

} | |

return (G2.last_lit == LIT_BUFSIZE - 1 || G2.last_dist == DIST_BUFSIZE); | |

/* We avoid equality with LIT_BUFSIZE because of wraparound at 64K | |

* on 16 bit machines and because stored blocks are restricted to | |

* 64K-1 bytes. | |

*/ | |

} | |

/* =========================================================================== | |

* Send the block data compressed using the given Huffman trees | |

*/ | |

static void compress_block(ct_data * ltree, ct_data * dtree) | |

{ | |

unsigned dist; /* distance of matched string */ | |

int lc; /* match length or unmatched char (if dist == 0) */ | |

unsigned lx = 0; /* running index in l_buf */ | |

unsigned dx = 0; /* running index in d_buf */ | |

unsigned fx = 0; /* running index in flag_buf */ | |

uch flag = 0; /* current flags */ | |

unsigned code; /* the code to send */ | |

int extra; /* number of extra bits to send */ | |

if (G2.last_lit != 0) do { | |

if ((lx & 7) == 0) | |

flag = G2.flag_buf[fx++]; | |

lc = G1.l_buf[lx++]; | |

if ((flag & 1) == 0) { | |

SEND_CODE(lc, ltree); /* send a literal byte */ | |

Tracecv(lc > ' ', (stderr, " '%c' ", lc)); | |

} else { | |

/* Here, lc is the match length - MIN_MATCH */ | |

code = G2.length_code[lc]; | |

SEND_CODE(code + LITERALS + 1, ltree); /* send the length code */ | |

extra = extra_lbits[code]; | |

if (extra != 0) { | |

lc -= G2.base_length[code]; | |

send_bits(lc, extra); /* send the extra length bits */ | |

} | |

dist = G1.d_buf[dx++]; | |

/* Here, dist is the match distance - 1 */ | |

code = D_CODE(dist); | |

Assert(code < D_CODES, "bad d_code"); | |

SEND_CODE(code, dtree); /* send the distance code */ | |

extra = extra_dbits[code]; | |

if (extra != 0) { | |

dist -= G2.base_dist[code]; | |

send_bits(dist, extra); /* send the extra distance bits */ | |

} | |

} /* literal or match pair ? */ | |

flag >>= 1; | |

} while (lx < G2.last_lit); | |

SEND_CODE(END_BLOCK, ltree); | |

} | |

/* =========================================================================== | |

* Determine the best encoding for the current block: dynamic trees, static | |

* trees or store, and output the encoded block to the zip file. This function | |

* returns the total compressed length for the file so far. | |

*/ | |

static ulg flush_block(char *buf, ulg stored_len, int eof) | |

{ | |

ulg opt_lenb, static_lenb; /* opt_len and static_len in bytes */ | |

int max_blindex; /* index of last bit length code of non zero freq */ | |

G2.flag_buf[G2.last_flags] = G2.flags; /* Save the flags for the last 8 items */ | |

/* Construct the literal and distance trees */ | |

build_tree(&G2.l_desc); | |

Tracev((stderr, "\nlit data: dyn %ld, stat %ld", G2.opt_len, G2.static_len)); | |

build_tree(&G2.d_desc); | |

Tracev((stderr, "\ndist data: dyn %ld, stat %ld", G2.opt_len, G2.static_len)); | |

/* At this point, opt_len and static_len are the total bit lengths of | |

* the compressed block data, excluding the tree representations. | |

*/ | |

/* Build the bit length tree for the above two trees, and get the index | |

* in bl_order of the last bit length code to send. | |

*/ | |

max_blindex = build_bl_tree(); | |

/* Determine the best encoding. Compute first the block length in bytes */ | |

opt_lenb = (G2.opt_len + 3 + 7) >> 3; | |

static_lenb = (G2.static_len + 3 + 7) >> 3; | |

Trace((stderr, | |

"\nopt %lu(%lu) stat %lu(%lu) stored %lu lit %u dist %u ", | |

opt_lenb, G2.opt_len, static_lenb, G2.static_len, stored_len, | |

G2.last_lit, G2.last_dist)); | |

if (static_lenb <= opt_lenb) | |

opt_lenb = static_lenb; | |

/* If compression failed and this is the first and last block, | |

* and if the zip file can be seeked (to rewrite the local header), | |

* the whole file is transformed into a stored file: | |

*/ | |

if (stored_len <= opt_lenb && eof && G2.compressed_len == 0L && seekable()) { | |

/* Since LIT_BUFSIZE <= 2*WSIZE, the input data must be there: */ | |

if (buf == NULL) | |

bb_error_msg("block vanished"); | |

copy_block(buf, (unsigned) stored_len, 0); /* without header */ | |

G2.compressed_len = stored_len << 3; | |

} else if (stored_len + 4 <= opt_lenb && buf != NULL) { | |

/* 4: two words for the lengths */ | |

/* The test buf != NULL is only necessary if LIT_BUFSIZE > WSIZE. | |

* Otherwise we can't have processed more than WSIZE input bytes since | |

* the last block flush, because compression would have been | |

* successful. If LIT_BUFSIZE <= WSIZE, it is never too late to | |

* transform a block into a stored block. | |

*/ | |

send_bits((STORED_BLOCK << 1) + eof, 3); /* send block type */ | |

G2.compressed_len = (G2.compressed_len + 3 + 7) & ~7L; | |

G2.compressed_len += (stored_len + 4) << 3; | |

copy_block(buf, (unsigned) stored_len, 1); /* with header */ | |

} else if (static_lenb == opt_lenb) { | |

send_bits((STATIC_TREES << 1) + eof, 3); | |

compress_block((ct_data *) G2.static_ltree, (ct_data *) G2.static_dtree); | |

G2.compressed_len += 3 + G2.static_len; | |

} else { | |

send_bits((DYN_TREES << 1) + eof, 3); | |

send_all_trees(G2.l_desc.max_code + 1, G2.d_desc.max_code + 1, | |

max_blindex + 1); | |

compress_block((ct_data *) G2.dyn_ltree, (ct_data *) G2.dyn_dtree); | |

G2.compressed_len += 3 + G2.opt_len; | |

} | |

Assert(G2.compressed_len == G1.bits_sent, "bad compressed size"); | |

init_block(); | |

if (eof) { | |

bi_windup(); | |

G2.compressed_len += 7; /* align on byte boundary */ | |

} | |

Tracev((stderr, "\ncomprlen %lu(%lu) ", G2.compressed_len >> 3, | |

G2.compressed_len - 7 * eof)); | |

return G2.compressed_len >> 3; | |

} | |

/* =========================================================================== | |

* Update a hash value with the given input byte | |

* IN assertion: all calls to 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 to INSERT_STRING are made with consecutive | |

* input characters and the first MIN_MATCH bytes of s are valid | |

* (except for the last MIN_MATCH-1 bytes of the input file). */ | |

#define INSERT_STRING(s, match_head) \ | |

do { \ | |

UPDATE_HASH(G1.ins_h, G1.window[(s) + MIN_MATCH-1]); \ | |

G1.prev[(s) & WMASK] = match_head = head[G1.ins_h]; \ | |

head[G1.ins_h] = (s); \ | |

} while (0) | |

static ulg deflate(void) | |

{ | |

IPos hash_head; /* head of hash chain */ | |

IPos prev_match; /* previous match */ | |

int flush; /* set if current block must be flushed */ | |

int match_available = 0; /* set if previous match exists */ | |

unsigned match_length = MIN_MATCH - 1; /* length of best match */ | |

/* Process the input block. */ | |

while (G1.lookahead != 0) { | |

/* Insert the string window[strstart .. strstart+2] in the | |

* dictionary, and set hash_head to the head of the hash chain: | |

*/ | |

INSERT_STRING(G1.strstart, hash_head); | |

/* Find the longest match, discarding those <= prev_length. | |

*/ | |

G1.prev_length = match_length; | |

prev_match = G1.match_start; | |

match_length = MIN_MATCH - 1; | |

if (hash_head != 0 && G1.prev_length < max_lazy_match | |

&& G1.strstart - hash_head <= MAX_DIST | |

) { | |

/* To simplify the code, we prevent matches with the string | |

* of window index 0 (in particular we have to avoid a match | |

* of the string with itself at the start of the input file). | |

*/ | |

match_length = longest_match(hash_head); | |

/* longest_match() sets match_start */ | |

if (match_length > G1.lookahead) | |

match_length = G1.lookahead; | |

/* Ignore a length 3 match if it is too distant: */ | |

if (match_length == MIN_MATCH && G1.strstart - G1.match_start > TOO_FAR) { | |

/* If prev_match is also MIN_MATCH, G1.match_start is garbage | |

* but we will ignore the current match anyway. | |

*/ | |

match_length--; | |

} | |

} | |

/* If there was a match at the previous step and the current | |

* match is not better, output the previous match: | |

*/ | |

if (G1.prev_length >= MIN_MATCH && match_length <= G1.prev_length) { | |

check_match(G1.strstart - 1, prev_match, G1.prev_length); | |

flush = ct_tally(G1.strstart - 1 - prev_match, G1.prev_length - MIN_MATCH); | |

/* Insert in hash table all strings up to the end of the match. | |

* strstart-1 and strstart are already inserted. | |

*/ | |

G1.lookahead -= G1.prev_length - 1; | |

G1.prev_length -= 2; | |

do { | |

G1.strstart++; | |

INSERT_STRING(G1.strstart, hash_head); | |

/* strstart never exceeds WSIZE-MAX_MATCH, so there are | |

* always MIN_MATCH bytes ahead. If lookahead < MIN_MATCH | |

* these bytes are garbage, but it does not matter since the | |

* next lookahead bytes will always be emitted as literals. | |

*/ | |

} while (--G1.prev_length != 0); | |

match_available = 0; | |

match_length = MIN_MATCH - 1; | |

G1.strstart++; | |

if (flush) { | |

FLUSH_BLOCK(0); | |

G1.block_start = G1.strstart; | |

} | |

} else if (match_available) { | |

/* If there was no match at the previous position, output a | |

* single literal. If there was a match but the current match | |

* is longer, truncate the previous match to a single literal. | |

*/ | |

Tracevv((stderr, "%c", G1.window[G1.strstart - 1])); | |

if (ct_tally(0, G1.window[G1.strstart - 1])) { | |

FLUSH_BLOCK(0); | |

G1.block_start = G1.strstart; | |

} | |

G1.strstart++; | |

G1.lookahead--; | |

} else { | |

/* There is no previous match to compare with, wait for | |

* the next step to decide. | |

*/ | |

match_available = 1; | |

G1.strstart++; | |

G1.lookahead--; | |

} | |

Assert(G1.strstart <= G1.isize && lookahead <= G1.isize, "a bit too far"); | |

/* Make sure that we always have enough lookahead, except | |

* at the end of the input file. We need MAX_MATCH bytes | |

* for the next match, plus MIN_MATCH bytes to insert the | |

* string following the next match. | |

*/ | |

while (G1.lookahead < MIN_LOOKAHEAD && !G1.eofile) | |

fill_window(); | |

} | |

if (match_available) | |

ct_tally(0, G1.window[G1.strstart - 1]); | |

return FLUSH_BLOCK(1); /* eof */ | |

} | |

/* =========================================================================== | |

* Initialize the bit string routines. | |

*/ | |

static void bi_init(void) | |

{ | |

G1.bi_buf = 0; | |

G1.bi_valid = 0; | |

#ifdef DEBUG | |

G1.bits_sent = 0L; | |

#endif | |

} | |

/* =========================================================================== | |

* Initialize the "longest match" routines for a new file | |

*/ | |

static void lm_init(ush * flagsp) | |

{ | |

unsigned j; | |

/* Initialize the hash table. */ | |

memset(head, 0, HASH_SIZE * sizeof(*head)); | |

/* prev will be initialized on the fly */ | |

/* speed options for the general purpose bit flag */ | |

*flagsp |= 2; /* FAST 4, SLOW 2 */ | |

/* ??? reduce max_chain_length for binary files */ | |

G1.strstart = 0; | |

G1.block_start = 0L; | |

G1.lookahead = file_read(G1.window, | |

sizeof(int) <= 2 ? (unsigned) WSIZE : 2 * WSIZE); | |

if (G1.lookahead == 0 || G1.lookahead == (unsigned) -1) { | |

G1.eofile = 1; | |

G1.lookahead = 0; | |

return; | |

} | |

G1.eofile = 0; | |

/* Make sure that we always have enough lookahead. This is important | |

* if input comes from a device such as a tty. | |

*/ | |

while (G1.lookahead < MIN_LOOKAHEAD && !G1.eofile) | |

fill_window(); | |

G1.ins_h = 0; | |

for (j = 0; j < MIN_MATCH - 1; j++) | |

UPDATE_HASH(G1.ins_h, G1.window[j]); | |

/* If lookahead < MIN_MATCH, ins_h is garbage, but this is | |

* not important since only literal bytes will be emitted. | |

*/ | |

} | |

/* =========================================================================== | |

* Allocate the match buffer, initialize the various tables and save the | |

* location of the internal file attribute (ascii/binary) and method | |

* (DEFLATE/STORE). | |

* One callsite in zip() | |

*/ | |

static void ct_init(void) | |

{ | |

int n; /* iterates over tree elements */ | |

int length; /* length value */ | |

int code; /* code value */ | |

int dist; /* distance index */ | |

G2.compressed_len = 0L; | |

#ifdef NOT_NEEDED | |

if (G2.static_dtree[0].Len != 0) | |

return; /* ct_init already called */ | |

#endif | |

/* Initialize the mapping length (0..255) -> length code (0..28) */ | |

length = 0; | |

for (code = 0; code < LENGTH_CODES - 1; code++) { | |

G2.base_length[code] = length; | |

for (n = 0; n < (1 << extra_lbits[code]); n++) { | |

G2.length_code[length++] = code; | |

} | |

} | |

Assert(length == 256, "ct_init: length != 256"); | |

/* Note that the length 255 (match length 258) can be represented | |

* in two different ways: code 284 + 5 bits or code 285, so we | |

* overwrite length_code[255] to use the best encoding: | |

*/ | |

G2.length_code[length - 1] = code; | |

/* Initialize the mapping dist (0..32K) -> dist code (0..29) */ | |

dist = 0; | |

for (code = 0; code < 16; code++) { | |

G2.base_dist[code] = dist; | |

for (n = 0; n < (1 << extra_dbits[code]); n++) { | |

G2.dist_code[dist++] = code; | |

} | |

} | |

Assert(dist == 256, "ct_init: dist != 256"); | |

dist >>= 7; /* from now on, all distances are divided by 128 */ | |

for (; code < D_CODES; code++) { | |

G2.base_dist[code] = dist << 7; | |

for (n = 0; n < (1 << (extra_dbits[code] - 7)); n++) { | |

G2.dist_code[256 + dist++] = code; | |

} | |

} | |

Assert(dist == 256, "ct_init: 256+dist != 512"); | |

/* Construct the codes of the static literal tree */ | |

/* already zeroed - it's in bss | |

for (n = 0; n <= MAX_BITS; n++) | |

G2.bl_count[n] = 0; */ | |

n = 0; | |

while (n <= 143) { | |

G2.static_ltree[n++].Len = 8; | |

G2.bl_count[8]++; | |

} | |

while (n <= 255) { | |

G2.static_ltree[n++].Len = 9; | |

G2.bl_count[9]++; | |

} | |

while (n <= 279) { | |

G2.static_ltree[n++].Len = 7; | |

G2.bl_count[7]++; | |

} | |

while (n <= 287) { | |

G2.static_ltree[n++].Len = 8; | |

G2.bl_count[8]++; | |

} | |

/* Codes 286 and 287 do not exist, but we must include them in the | |

* tree construction to get a canonical Huffman tree (longest code | |

* all ones) | |

*/ | |

gen_codes((ct_data *) G2.static_ltree, L_CODES + 1); | |

/* The static distance tree is trivial: */ | |

for (n = 0; n < D_CODES; n++) { | |

G2.static_dtree[n].Len = 5; | |

G2.static_dtree[n].Code = bi_reverse(n, 5); | |

} | |

/* Initialize the first block of the first file: */ | |

init_block(); | |

} | |

/* =========================================================================== | |

* Deflate in to out. | |

* IN assertions: the input and output buffers are cleared. | |

*/ | |

static void zip(ulg time_stamp) | |

{ | |

ush deflate_flags = 0; /* pkzip -es, -en or -ex equivalent */ | |

G1.outcnt = 0; | |

/* Write the header to the gzip file. See algorithm.doc for the format */ | |

/* magic header for gzip files: 1F 8B */ | |

/* compression method: 8 (DEFLATED) */ | |

/* general flags: 0 */ | |

put_32bit(0x00088b1f); | |

put_32bit(time_stamp); | |

/* Write deflated file to zip file */ | |

G1.crc = ~0; | |

bi_init(); | |

ct_init(); | |

lm_init(&deflate_flags); | |

put_8bit(deflate_flags); /* extra flags */ | |

put_8bit(3); /* OS identifier = 3 (Unix) */ | |

deflate(); | |

/* Write the crc and uncompressed size */ | |

put_32bit(~G1.crc); | |

put_32bit(G1.isize); | |

flush_outbuf(); | |

} | |

/* ======================================================================== */ | |

static | |

IF_DESKTOP(long long) int FAST_FUNC pack_gzip(unpack_info_t *info UNUSED_PARAM) | |

{ | |

struct stat s; | |

/* Clear input and output buffers */ | |

G1.outcnt = 0; | |

#ifdef DEBUG | |

G1.insize = 0; | |

#endif | |

G1.isize = 0; | |

/* Reinit G2.xxx */ | |

memset(&G2, 0, sizeof(G2)); | |

G2.l_desc.dyn_tree = G2.dyn_ltree; | |

G2.l_desc.static_tree = G2.static_ltree; | |

G2.l_desc.extra_bits = extra_lbits; | |

G2.l_desc.extra_base = LITERALS + 1; | |

G2.l_desc.elems = L_CODES; | |

G2.l_desc.max_length = MAX_BITS; | |

//G2.l_desc.max_code = 0; | |

G2.d_desc.dyn_tree = G2.dyn_dtree; | |

G2.d_desc.static_tree = G2.static_dtree; | |

G2.d_desc.extra_bits = extra_dbits; | |

//G2.d_desc.extra_base = 0; | |

G2.d_desc.elems = D_CODES; | |

G2.d_desc.max_length = MAX_BITS; | |

//G2.d_desc.max_code = 0; | |

G2.bl_desc.dyn_tree = G2.bl_tree; | |

//G2.bl_desc.static_tree = NULL; | |

G2.bl_desc.extra_bits = extra_blbits, | |

//G2.bl_desc.extra_base = 0; | |

G2.bl_desc.elems = BL_CODES; | |

G2.bl_desc.max_length = MAX_BL_BITS; | |

//G2.bl_desc.max_code = 0; | |

s.st_ctime = 0; | |

fstat(STDIN_FILENO, &s); | |

zip(s.st_ctime); | |

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_GUNZIP | |

"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" | |

; | |

#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_GUNZIP | |

int gzip_main(int argc, char **argv) | |

#else | |

int gzip_main(int argc UNUSED_PARAM, char **argv) | |

#endif | |

{ | |

unsigned opt; | |

#if ENABLE_FEATURE_GZIP_LONG_OPTIONS | |

applet_long_options = gzip_longopts; | |

#endif | |

/* Must match bbunzip's constants OPT_STDOUT, OPT_FORCE! */ | |

opt = getopt32(argv, "cfv" IF_GUNZIP("dt") "q123456789n"); | |

#if ENABLE_GUNZIP /* gunzip_main may not be visible... */ | |

if (opt & 0x18) // -d and/or -t | |

return gunzip_main(argc, argv); | |

#endif | |

option_mask32 &= 0x7; /* ignore -q, -0..9 */ | |

//if (opt & 0x1) // -c | |

//if (opt & 0x2) // -f | |

//if (opt & 0x4) // -v | |

argv += optind; | |

SET_PTR_TO_GLOBALS((char *)xzalloc(sizeof(struct globals)+sizeof(struct globals2)) | |

+ sizeof(struct globals)); | |

/* 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); | |

/* Initialise the CRC32 table */ | |

G1.crc_32_tab = crc32_filltable(NULL, 0); | |

return bbunpack(argv, pack_gzip, append_ext, "gz"); | |

} |