2247 lines
71 KiB
C
2247 lines
71 KiB
C
/* vi: set sw=4 ts=4: */
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/*
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* Gzip implementation for busybox
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*
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* Based on GNU gzip Copyright (C) 1992-1993 Jean-loup Gailly.
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*
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* Originally adjusted for busybox by Charles P. Wright <cpw@unix.asb.com>
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* "this is a stripped down version of gzip I put into busybox, it does
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* only standard in to standard out with -9 compression. It also requires
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* the zcat module for some important functions."
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*
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* Adjusted further by Erik Andersen <andersen@codepoet.org> to support
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* files as well as stdin/stdout, and to generally behave itself wrt
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* command line handling.
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*
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* Licensed under GPLv2 or later, see file LICENSE in this source tree.
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*/
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/* TODO: full support for -v for DESKTOP
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* "/usr/bin/gzip -v a bogus aa" should say:
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a: 85.1% -- replaced with a.gz
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gzip: bogus: No such file or directory
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aa: 85.1% -- replaced with aa.gz
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*/
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//config:config GZIP
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//config: bool "gzip (19 kb)"
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//config: default y
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//config: help
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//config: gzip is used to compress files.
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//config: It's probably the most widely used UNIX compression program.
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//config:
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//config:config FEATURE_GZIP_LONG_OPTIONS
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//config: bool "Enable long options"
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//config: default y
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//config: depends on GZIP && LONG_OPTS
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//config:
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//config:config GZIP_FAST
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//config: int "Trade memory for speed (0:small,slow - 2:fast,big)"
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//config: default 0
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//config: range 0 2
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//config: depends on GZIP
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//config: help
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//config: Enable big memory options for gzip.
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//config: 0: small buffers, small hash-tables
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//config: 1: larger buffers, larger hash-tables
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//config: 2: larger buffers, largest hash-tables
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//config: Larger models may give slightly better compression
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//config:
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//config:config FEATURE_GZIP_LEVELS
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//config: bool "Enable compression levels"
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//config: default n
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//config: depends on GZIP
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//config: help
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//config: Enable support for compression levels 4-9. The default level
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//config: is 6. If levels 1-3 are specified, 4 is used.
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//config: If this option is not selected, -N options are ignored and -9
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//config: is used.
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//config:
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//config:config FEATURE_GZIP_DECOMPRESS
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//config: bool "Enable decompression"
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//config: default y
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//config: depends on GZIP || GUNZIP || ZCAT
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//config: help
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//config: Enable -d (--decompress) and -t (--test) options for gzip.
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//config: This will be automatically selected if gunzip or zcat is
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//config: enabled.
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//applet:IF_GZIP(APPLET(gzip, BB_DIR_BIN, BB_SUID_DROP))
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//kbuild:lib-$(CONFIG_GZIP) += gzip.o
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//usage:#define gzip_trivial_usage
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//usage: "[-cfk" IF_FEATURE_GZIP_DECOMPRESS("dt") IF_FEATURE_GZIP_LEVELS("123456789") "] [FILE]..."
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//usage:#define gzip_full_usage "\n\n"
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//usage: "Compress FILEs (or stdin)\n"
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//usage: IF_FEATURE_GZIP_LEVELS(
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//usage: "\n -1..9 Compression level"
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//usage: )
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//usage: IF_FEATURE_GZIP_DECOMPRESS(
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//usage: "\n -d Decompress"
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//usage: "\n -t Test file integrity"
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//usage: )
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//usage: "\n -c Write to stdout"
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//usage: "\n -f Force"
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//usage: "\n -k Keep input files"
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//usage:
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//usage:#define gzip_example_usage
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//usage: "$ ls -la /tmp/busybox*\n"
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//usage: "-rw-rw-r-- 1 andersen andersen 1761280 Apr 14 17:47 /tmp/busybox.tar\n"
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//usage: "$ gzip /tmp/busybox.tar\n"
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//usage: "$ ls -la /tmp/busybox*\n"
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//usage: "-rw-rw-r-- 1 andersen andersen 554058 Apr 14 17:49 /tmp/busybox.tar.gz\n"
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#include "libbb.h"
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#include "bb_archive.h"
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/* ===========================================================================
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*/
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//#define DEBUG 1
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/* Diagnostic functions */
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#ifdef DEBUG
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static int verbose;
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# define Assert(cond,msg) { if (!(cond)) bb_error_msg(msg); }
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# define Trace(x) fprintf x
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# define Tracev(x) {if (verbose) fprintf x; }
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# define Tracevv(x) {if (verbose > 1) fprintf x; }
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# define Tracec(c,x) {if (verbose && (c)) fprintf x; }
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# define Tracecv(c,x) {if (verbose > 1 && (c)) fprintf x; }
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#else
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# define Assert(cond,msg)
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# define Trace(x)
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# define Tracev(x)
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# define Tracevv(x)
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# define Tracec(c,x)
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# define Tracecv(c,x)
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#endif
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/* ===========================================================================
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*/
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#if CONFIG_GZIP_FAST == 0
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# define SMALL_MEM
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#elif CONFIG_GZIP_FAST == 1
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# define MEDIUM_MEM
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#elif CONFIG_GZIP_FAST == 2
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# define BIG_MEM
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#else
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# error "Invalid CONFIG_GZIP_FAST value"
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#endif
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#ifndef INBUFSIZ
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# ifdef SMALL_MEM
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# define INBUFSIZ 0x2000 /* input buffer size */
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# else
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# define INBUFSIZ 0x8000 /* input buffer size */
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# endif
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#endif
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#ifndef OUTBUFSIZ
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# ifdef SMALL_MEM
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# define OUTBUFSIZ 8192 /* output buffer size */
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# else
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# define OUTBUFSIZ 16384 /* output buffer size */
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# endif
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#endif
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#ifndef DIST_BUFSIZE
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# ifdef SMALL_MEM
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# define DIST_BUFSIZE 0x2000 /* buffer for distances, see trees.c */
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# else
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# define DIST_BUFSIZE 0x8000 /* buffer for distances, see trees.c */
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# endif
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#endif
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/* gzip flag byte */
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#define ASCII_FLAG 0x01 /* bit 0 set: file probably ascii text */
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#define CONTINUATION 0x02 /* bit 1 set: continuation of multi-part gzip file */
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#define EXTRA_FIELD 0x04 /* bit 2 set: extra field present */
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#define ORIG_NAME 0x08 /* bit 3 set: original file name present */
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#define COMMENT 0x10 /* bit 4 set: file comment present */
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#define RESERVED 0xC0 /* bit 6,7: reserved */
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/* internal file attribute */
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#define UNKNOWN 0xffff
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#define BINARY 0
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#define ASCII 1
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#ifndef WSIZE
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# define WSIZE 0x8000 /* window size--must be a power of two, and */
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#endif /* at least 32K for zip's deflate method */
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#define MIN_MATCH 3
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#define MAX_MATCH 258
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/* The minimum and maximum match lengths */
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#define MIN_LOOKAHEAD (MAX_MATCH+MIN_MATCH+1)
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/* Minimum amount of lookahead, except at the end of the input file.
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* See deflate.c for comments about the MIN_MATCH+1.
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*/
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#define MAX_DIST (WSIZE-MIN_LOOKAHEAD)
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/* In order to simplify the code, particularly on 16 bit machines, match
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* distances are limited to MAX_DIST instead of WSIZE.
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*/
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#ifndef MAX_PATH_LEN
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# define MAX_PATH_LEN 1024 /* max pathname length */
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#endif
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#define seekable() 0 /* force sequential output */
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#define translate_eol 0 /* no option -a yet */
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#ifndef BITS
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# define BITS 16
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#endif
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#define INIT_BITS 9 /* Initial number of bits per code */
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#define BIT_MASK 0x1f /* Mask for 'number of compression bits' */
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/* Mask 0x20 is reserved to mean a fourth header byte, and 0x40 is free.
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* It's a pity that old uncompress does not check bit 0x20. That makes
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* extension of the format actually undesirable because old compress
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* would just crash on the new format instead of giving a meaningful
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* error message. It does check the number of bits, but it's more
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* helpful to say "unsupported format, get a new version" than
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* "can only handle 16 bits".
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*/
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#ifdef MAX_EXT_CHARS
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# define MAX_SUFFIX MAX_EXT_CHARS
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#else
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# define MAX_SUFFIX 30
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#endif
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/* ===========================================================================
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* Compile with MEDIUM_MEM to reduce the memory requirements or
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* with SMALL_MEM to use as little memory as possible. Use BIG_MEM if the
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* entire input file can be held in memory (not possible on 16 bit systems).
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* Warning: defining these symbols affects HASH_BITS (see below) and thus
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* affects the compression ratio. The compressed output
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* is still correct, and might even be smaller in some cases.
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*/
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#ifdef SMALL_MEM
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# define HASH_BITS 13 /* Number of bits used to hash strings */
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#endif
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#ifdef MEDIUM_MEM
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# define HASH_BITS 14
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#endif
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#ifndef HASH_BITS
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# define HASH_BITS 15
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/* For portability to 16 bit machines, do not use values above 15. */
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#endif
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#define HASH_SIZE (unsigned)(1<<HASH_BITS)
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#define HASH_MASK (HASH_SIZE-1)
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#define WMASK (WSIZE-1)
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/* HASH_SIZE and WSIZE must be powers of two */
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#ifndef TOO_FAR
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# define TOO_FAR 4096
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#endif
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/* Matches of length 3 are discarded if their distance exceeds TOO_FAR */
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/* ===========================================================================
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* These types are not really 'char', 'short' and 'long'
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*/
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typedef uint8_t uch;
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typedef uint16_t ush;
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typedef uint32_t ulg;
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typedef int32_t lng;
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typedef ush Pos;
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typedef unsigned IPos;
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/* A Pos is an index in the character window. We use short instead of int to
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* save space in the various tables. IPos is used only for parameter passing.
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*/
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enum {
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WINDOW_SIZE = 2 * WSIZE,
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/* window size, 2*WSIZE except for MMAP or BIG_MEM, where it is the
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* input file length plus MIN_LOOKAHEAD.
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*/
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#if !ENABLE_FEATURE_GZIP_LEVELS
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max_chain_length = 4096,
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/* To speed up deflation, hash chains are never searched beyond this length.
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* A higher limit improves compression ratio but degrades the speed.
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*/
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max_lazy_match = 258,
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/* Attempt to find a better match only when the current match is strictly
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* smaller than this value. This mechanism is used only for compression
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* levels >= 4.
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*/
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max_insert_length = max_lazy_match,
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/* Insert new strings in the hash table only if the match length
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* is not greater than this length. This saves time but degrades compression.
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* max_insert_length is used only for compression levels <= 3.
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*/
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good_match = 32,
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/* Use a faster search when the previous match is longer than this */
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/* Values for max_lazy_match, good_match and max_chain_length, depending on
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* the desired pack level (0..9). The values given below have been tuned to
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* exclude worst case performance for pathological files. Better values may be
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* found for specific files.
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*/
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nice_match = 258, /* Stop searching when current match exceeds this */
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/* Note: the deflate() code requires max_lazy >= MIN_MATCH and max_chain >= 4
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* For deflate_fast() (levels <= 3) good is ignored and lazy has a different
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* meaning.
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*/
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#endif /* ENABLE_FEATURE_GZIP_LEVELS */
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};
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struct globals {
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/* =========================================================================== */
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/* global buffers, allocated once */
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#define DECLARE(type, array, size) \
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type * array
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#define ALLOC(type, array, size) \
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array = xzalloc((size_t)(((size)+1L)/2) * 2*sizeof(type))
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#define FREE(array) \
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do { free(array); array = NULL; } while (0)
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/* buffer for literals or lengths */
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/* DECLARE(uch, l_buf, LIT_BUFSIZE); */
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DECLARE(uch, l_buf, INBUFSIZ);
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DECLARE(ush, d_buf, DIST_BUFSIZE);
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DECLARE(uch, outbuf, OUTBUFSIZ);
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/* Sliding window. Input bytes are read into the second half of the window,
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* and move to the first half later to keep a dictionary of at least WSIZE
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* bytes. With this organization, matches are limited to a distance of
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* WSIZE-MAX_MATCH bytes, but this ensures that IO is always
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* performed with a length multiple of the block size. Also, it limits
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* the window size to 64K, which is quite useful on MSDOS.
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* To do: limit the window size to WSIZE+BSZ if SMALL_MEM (the code would
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* be less efficient).
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*/
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DECLARE(uch, window, 2L * WSIZE);
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/* Link to older string with same hash index. To limit the size of this
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* array to 64K, this link is maintained only for the last 32K strings.
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* An index in this array is thus a window index modulo 32K.
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*/
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/* DECLARE(Pos, prev, WSIZE); */
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DECLARE(ush, prev, 1L << BITS);
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/* Heads of the hash chains or 0. */
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/* DECLARE(Pos, head, 1<<HASH_BITS); */
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#define head (G1.prev + WSIZE) /* hash head (see deflate.c) */
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/* =========================================================================== */
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/* all members below are zeroed out in pack_gzip() for each next file */
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uint32_t crc; /* shift register contents */
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/*uint32_t *crc_32_tab;*/
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#if ENABLE_FEATURE_GZIP_LEVELS
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unsigned max_chain_length;
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unsigned max_lazy_match;
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unsigned good_match;
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unsigned nice_match;
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#define max_chain_length (G1.max_chain_length)
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#define max_lazy_match (G1.max_lazy_match)
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#define good_match (G1.good_match)
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#define nice_match (G1.nice_match)
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#endif
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/* window position at the beginning of the current output block. Gets
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* negative when the window is moved backwards.
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*/
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lng block_start;
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unsigned ins_h; /* hash index of string to be inserted */
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/* Number of bits by which ins_h and del_h must be shifted at each
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* input step. It must be such that after MIN_MATCH steps, the oldest
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* byte no longer takes part in the hash key, that is:
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* H_SHIFT * MIN_MATCH >= HASH_BITS
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*/
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#define H_SHIFT ((HASH_BITS+MIN_MATCH-1) / MIN_MATCH)
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/* Length of the best match at previous step. Matches not greater than this
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* are discarded. This is used in the lazy match evaluation.
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*/
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unsigned prev_length;
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unsigned strstart; /* start of string to insert */
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unsigned match_start; /* start of matching string */
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unsigned lookahead; /* number of valid bytes ahead in window */
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/* number of input bytes */
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ulg isize; /* only 32 bits stored in .gz file */
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/* bbox always use stdin/stdout */
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#define ifd STDIN_FILENO /* input file descriptor */
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#define ofd STDOUT_FILENO /* output file descriptor */
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#ifdef DEBUG
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unsigned insize; /* valid bytes in l_buf */
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#endif
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unsigned outcnt; /* bytes in output buffer */
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smallint eofile; /* flag set at end of input file */
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/* ===========================================================================
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* Local data used by the "bit string" routines.
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*/
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/* Output buffer. bits are inserted starting at the bottom (least significant
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* bits).
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*/
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unsigned bi_buf; /* was unsigned short */
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#undef BUF_SIZE
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#define BUF_SIZE (int)(8 * sizeof(G1.bi_buf))
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/* Number of bits used within bi_buf. (bi_buf might be implemented on
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* more than 16 bits on some systems.)
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*/
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unsigned bi_valid;
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#ifdef DEBUG
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ulg bits_sent; /* bit length of the compressed data */
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# define DEBUG_bits_sent(v) (void)(G1.bits_sent v)
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#else
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# define DEBUG_bits_sent(v) ((void)0)
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#endif
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};
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#define G1 (*(ptr_to_globals - 1))
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/* ===========================================================================
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* Write the output buffer outbuf[0..outcnt-1] and update bytes_out.
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* (used for the compressed data only)
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*/
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static void flush_outbuf(void)
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{
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if (G1.outcnt == 0)
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return;
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xwrite(ofd, (char *) G1.outbuf, G1.outcnt);
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G1.outcnt = 0;
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}
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/* ===========================================================================
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*/
|
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/* put_8bit is used for the compressed output */
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#define put_8bit(c) \
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do { \
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G1.outbuf[G1.outcnt++] = (c); \
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if (G1.outcnt == OUTBUFSIZ) \
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flush_outbuf(); \
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} while (0)
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|
|
/* Output a 16 bit value, lsb first */
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|
static void put_16bit(ush w)
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{
|
|
/* GCC 4.2.1 won't optimize out redundant loads of G1.outcnt
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* (probably because of fear of aliasing with G1.outbuf[]
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* stores), do it explicitly:
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*/
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unsigned outcnt = G1.outcnt;
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uch *dst = &G1.outbuf[outcnt];
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#if BB_UNALIGNED_MEMACCESS_OK && BB_LITTLE_ENDIAN
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if (outcnt < OUTBUFSIZ-2) {
|
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/* Common case */
|
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ush *dst16 = (void*) dst;
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*dst16 = w; /* unaligned LSB 16-bit store */
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G1.outcnt = outcnt + 2;
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return;
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}
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*dst = (uch)w;
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w >>= 8;
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G1.outcnt = ++outcnt;
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#else
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*dst = (uch)w;
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w >>= 8;
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if (outcnt < OUTBUFSIZ-2) {
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/* Common case */
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dst[1] = w;
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G1.outcnt = outcnt + 2;
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return;
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}
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G1.outcnt = ++outcnt;
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#endif
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|
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/* Slowpath: we will need to do flush_outbuf() */
|
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if (outcnt == OUTBUFSIZ)
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flush_outbuf(); /* here */
|
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put_8bit(w); /* or here */
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}
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#define OPTIMIZED_PUT_32BIT (CONFIG_GZIP_FAST > 0 && BB_UNALIGNED_MEMACCESS_OK && BB_LITTLE_ENDIAN)
|
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static void put_32bit(ulg n)
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{
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if (OPTIMIZED_PUT_32BIT) {
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unsigned outcnt = G1.outcnt;
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if (outcnt < OUTBUFSIZ-4) {
|
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/* Common case */
|
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ulg *dst32 = (void*) &G1.outbuf[outcnt];
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*dst32 = n; /* unaligned LSB 32-bit store */
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|
//bb_error_msg("%p", dst32); // store alignment debugging
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G1.outcnt = outcnt + 4;
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return;
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}
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}
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put_16bit(n);
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|
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_table = crc32_filltable(NULL, 0);
|
|
|
|
argv += optind;
|
|
return bbunpack(argv, pack_gzip, append_ext, "gz");
|
|
}
|