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gzip cleanup part #2

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This commit is contained in:
Denis Vlasenko 2007-01-07 19:38:06 +00:00
parent ad403413c7
commit 30551fd6da
1 changed files with 50 additions and 210 deletions
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260
archival/gzip.c
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@ -141,19 +141,19 @@ aa: 85.1% -- replaced with aa.gz
/* Diagnostic functions */
#ifdef DEBUG
# define Assert(cond,msg) {if(!(cond)) bb_error_msg(msg);}
# define Trace(x) fprintf x
# define Tracev(x) {if (verbose) fprintf x ;}
# define Tracevv(x) {if (verbose>1) fprintf x ;}
# define Tracec(c,x) {if (verbose && (c)) fprintf x ;}
# define Tracecv(c,x) {if (verbose>1 && (c)) fprintf x ;}
# define Assert(cond,msg) {if(!(cond)) bb_error_msg(msg);}
# define Trace(x) fprintf x
# define Tracev(x) {if (verbose) fprintf x ;}
# define Tracevv(x) {if (verbose>1) fprintf x ;}
# define Tracec(c,x) {if (verbose && (c)) fprintf x ;}
# define Tracecv(c,x) {if (verbose>1 && (c)) fprintf x ;}
#else
# define Assert(cond,msg)
# define Trace(x)
# define Tracev(x)
# define Tracevv(x)
# define Tracec(c,x)
# define Tracecv(c,x)
# define Assert(cond,msg)
# define Trace(x)
# define Tracev(x)
# define Tracevv(x)
# define Tracec(c,x)
# define Tracecv(c,x)
#endif
typedef unsigned char uch;
@ -163,7 +163,7 @@ typedef unsigned long ulg;
/* from zip.c: */
static int zip(int in, int out);
static int file_read(char *buf, unsigned size);
static unsigned file_read(void *buf, unsigned size);
/* from deflate.c */
static void lm_init(ush * flags);
@ -180,7 +180,6 @@ static void send_bits(int value, int length);
static unsigned bi_reverse(unsigned value, int length);
static void bi_windup(void);
static void copy_block(char *buf, unsigned len, int header);
static int (*read_buf) (char *buf, unsigned size);
static void flush_outbuf(void);
@ -297,22 +296,6 @@ static void clear_bufs(void)
isize = 0L;
}
/* ===========================================================================
* Does the same as write(), but also handles partial pipe writes and checks
* for error return.
*/
static void write_buf(int fd, void *buf, unsigned cnt)
{
unsigned n;
while ((n = write(fd, buf, cnt)) != cnt) {
if (n == (unsigned) (-1))
bb_error_msg_and_die(bb_msg_write_error);
cnt -= n;
buf = (void *) ((char *) buf + n);
}
}
/* ===========================================================================
* Run a set of bytes through the crc shift register. If s is a NULL
* pointer, then initialize the crc shift register contents instead.
@ -333,62 +316,9 @@ static uint32_t updcrc(uch * s, unsigned n)
} while (--n);
}
crc = c;
return ~c;
return c;
}
/* bits.c -- output variable-length bit strings
* Copyright (C) 1992-1993 Jean-loup Gailly
* This is free software; you can redistribute it and/or modify it under the
* terms of the GNU General Public License, see the file COPYING.
*/
/*
* PURPOSE
*
* Output variable-length bit strings. Compression can be done
* to a file or to memory. (The latter is not supported in this version.)
*
* DISCUSSION
*
* The PKZIP "deflate" file format interprets compressed file data
* as a sequence of bits. Multi-bit strings in the file may cross
* byte boundaries without restriction.
*
* The first bit of each byte is the low-order bit.
*
* The routines in this file allow a variable-length bit value to
* be output right-to-left (useful for literal values). For
* left-to-right output (useful for code strings from the tree routines),
* the bits must have been reversed first with bi_reverse().
*
* For in-memory compression, the compressed bit stream goes directly
* into the requested output buffer. The input data is read in blocks
* by the mem_read() function. The buffer is limited to 64K on 16 bit
* machines.
*
* INTERFACE
*
* void bi_init (FILE *zipfile)
* Initialize the bit string routines.
*
* void send_bits (int value, int length)
* Write out a bit string, taking the source bits right to
* left.
*
* int bi_reverse (int value, int length)
* Reverse the bits of a bit string, taking the source bits left to
* right and emitting them right to left.
*
* void bi_windup (void)
* Write out any remaining bits in an incomplete byte.
*
* void copy_block(char *buf, unsigned len, int header)
* Copy a stored block to the zip file, storing first the length and
* its one's complement if requested.
*
*/
/* ===========================================================================
* Initialize the bit string routines.
*/
@ -400,13 +330,6 @@ static void bi_init(int zipfile)
#ifdef DEBUG
bits_sent = 0L;
#endif
/* Set the defaults for file compression. They are set by memcompress
* for in-memory compression.
*/
if (zfile != NO_FILE) {
read_buf = file_read;
}
}
/* ===========================================================================
@ -418,7 +341,7 @@ static void send_bits(int value, int length)
#ifdef DEBUG
Tracev((stderr, " l %2d v %4x ", length, value));
Assert(length > 0 && length <= 15, "invalid length");
bits_sent += (ulg) length;
bits_sent += length;
#endif
/* If not enough room in bi_buf, use (valid) bits from bi_buf and
* (16 - bi_valid) bits from value, leaving (width - (16-bi_valid))
@ -477,8 +400,8 @@ static void copy_block(char *buf, unsigned len, int header)
bi_windup(); /* align on byte boundary */
if (header) {
put_16bit((ush) len);
put_16bit((ush) ~ len);
put_16bit(len);
put_16bit(~len);
#ifdef DEBUG
bits_sent += 2 * 16;
#endif
@ -491,61 +414,7 @@ static void copy_block(char *buf, unsigned len, int header)
}
}
/* deflate.c -- compress data using the deflation algorithm
* Copyright (C) 1992-1993 Jean-loup Gailly
* This is free software; you can redistribute it and/or modify it under the
* terms of the GNU General Public License, see the file COPYING.
*/
/*
* PURPOSE
*
* Identify new text as repetitions of old text within a fixed-
* length sliding window trailing behind the new text.
*
* DISCUSSION
*
* The "deflation" process depends on being able to identify portions
* of the input text which are identical to earlier input (within a
* sliding window trailing behind the input currently being processed).
*
* The most straightforward technique turns out to be the fastest for
* most input files: try all possible matches and select the longest.
* The key feature of this algorithm is that insertions into the string
* dictionary are very simple and thus fast, and deletions are avoided
* completely. Insertions are performed at each input character, whereas
* string matches are performed only when the previous match ends. So it
* is preferable to spend more time in matches to allow very fast string
* insertions and avoid deletions. The matching algorithm for small
* strings is inspired from that of Rabin & Karp. A brute force approach
* is used to find longer strings when a small match has been found.
* A similar algorithm is used in comic (by Jan-Mark Wams) and freeze
* (by Leonid Broukhis).
* A previous version of this file used a more sophisticated algorithm
* (by Fiala and Greene) which is guaranteed to run in linear amortized
* time, but has a larger average cost, uses more memory and is patented.
* However the F&G algorithm may be faster for some highly redundant
* files if the parameter max_chain_length (described below) is too large.
*
* ACKNOWLEDGMENTS
*
* The idea of lazy evaluation of matches is due to Jan-Mark Wams, and
* I found it in 'freeze' written by Leonid Broukhis.
* Thanks to many info-zippers for bug reports and testing.
*
* REFERENCES
*
* APPNOTE.TXT documentation file in PKZIP 1.93a distribution.
*
* A description of the Rabin and Karp algorithm is given in the book
* "Algorithms" by R. Sedgewick, Addison-Wesley, p252.
*
* Fiala,E.R., and Greene,D.H.
* Data Compression with Finite Windows, Comm.ACM, 32,4 (1989) 490-595
*
* INTERFACE
*
* void lm_init (int pack_level, ush *flags)
/* void lm_init (int pack_level, ush *flags)
* Initialize the "longest match" routines for a new file
*
* ulg deflate (void)
@ -752,11 +621,12 @@ static void lm_init(ush * flags)
strstart = 0;
block_start = 0L;
lookahead = read_buf((char *) window,
sizeof(int) <= 2 ? (unsigned) WSIZE : 2 * WSIZE);
lookahead = file_read(window,
sizeof(int) <= 2 ? (unsigned) WSIZE : 2 * WSIZE);
if (lookahead == 0 || lookahead == (unsigned) EOF) {
eofile = 1, lookahead = 0;
if (lookahead == 0 || lookahead == (unsigned) -1) {
eofile = 1;
lookahead = 0;
return;
}
eofile = 0;
@ -935,8 +805,8 @@ static void fill_window(void)
}
/* At this point, more >= 2 */
if (!eofile) {
n = read_buf((char *) window + strstart + lookahead, more);
if (n == 0 || n == (unsigned) EOF) {
n = file_read(window + strstart + lookahead, more);
if (n == 0 || n == (unsigned) -1) {
eofile = 1;
} else {
lookahead += n;
@ -977,8 +847,9 @@ static ulg deflate(void)
prev_length = match_length, prev_match = match_start;
match_length = MIN_MATCH - 1;
if (hash_head != NIL && prev_length < max_lazy_match &&
strstart - hash_head <= MAX_DIST) {
if (hash_head != 0 && prev_length < max_lazy_match
&& strstart - hash_head <= MAX_DIST
) {
/* To simplify the code, we prevent matches with the string
* of window index 0 (in particular we have to avoid a match
* of the string with itself at the start of the input file).
@ -1024,7 +895,6 @@ static ulg deflate(void)
strstart++;
if (flush)
FLUSH_BLOCK(0), block_start = strstart;
} else if (match_available) {
/* If there was no match at the previous position, output a
* single literal. If there was a match but the current match
@ -1060,30 +930,6 @@ static ulg deflate(void)
return FLUSH_BLOCK(1); /* eof */
}
/* gzip (GNU zip) -- compress files with zip algorithm and 'compress' interface
* Copyright (C) 1992-1993 Jean-loup Gailly
* The unzip code was written and put in the public domain by Mark Adler.
* Portions of the lzw code are derived from the public domain 'compress'
* written by Spencer Thomas, Joe Orost, James Woods, Jim McKie, Steve Davies,
* Ken Turkowski, Dave Mack and Peter Jannesen.
*
* See the license_msg below and the file COPYING for the software license.
* See the file algorithm.doc for the compression algorithms and file formats.
*/
/* Compress files with zip algorithm and 'compress' interface.
* See usage() and help() functions below for all options.
* Outputs:
* file.gz: compressed file with same mode, owner, and utimes
* or stdout with -c option or if stdin used as input.
* If the output file name had to be truncated, the original name is kept
* in the compressed file.
*/
/* configuration */
typedef struct dirent dir_type;
/* ======================================================================== */
static void abort_gzip(int ATTRIBUTE_UNUSED ignored)
{
@ -1268,12 +1114,12 @@ int gzip_main(int argc, char **argv)
*
* INTERFACE
*
* void ct_init (ush *attr, int *methodp)
* void ct_init(ush *attr, int *methodp)
* Allocate the match buffer, initialize the various tables and save
* the location of the internal file attribute (ascii/binary) and
* method (DEFLATE/STORE)
*
* void ct_tally (int dist, int lc);
* void ct_tally(int dist, int lc);
* Save the match info and tally the frequency counts.
*
* long flush_block (char *buf, ulg stored_len, int eof)
@ -1433,17 +1279,17 @@ typedef struct tree_desc {
int max_code; /* largest code with non zero frequency */
} tree_desc;
static tree_desc l_desc =
{ dyn_ltree, static_ltree, extra_lbits, LITERALS + 1, L_CODES,
MAX_BITS, 0
static tree_desc l_desc = {
dyn_ltree, static_ltree, extra_lbits,
LITERALS + 1, L_CODES, MAX_BITS, 0
};
static tree_desc d_desc =
{ dyn_dtree, static_dtree, extra_dbits, 0, D_CODES, MAX_BITS, 0 };
static tree_desc d_desc = {
dyn_dtree, static_dtree, extra_dbits, 0, D_CODES, MAX_BITS, 0
};
static tree_desc bl_desc =
{ bl_tree, (ct_data *) 0, extra_blbits, 0, BL_CODES, MAX_BL_BITS,
0
static tree_desc bl_desc = {
bl_tree, NULL, extra_blbits, 0, BL_CODES, MAX_BL_BITS, 0
};
@ -1451,8 +1297,9 @@ static ush bl_count[MAX_BITS + 1];
/* number of codes at each bit length for an optimal tree */
static const uch bl_order[BL_CODES]
= { 16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15 };
static const uch bl_order[BL_CODES] = {
16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15
};
/* The lengths of the bit length codes are sent in order of decreasing
* probability, to avoid transmitting the lengths for unused bit length codes.
@ -2334,13 +2181,6 @@ static void set_file_type(void)
}
}
/* zip.c -- compress files to the gzip or pkzip format
* Copyright (C) 1992-1993 Jean-loup Gailly
* This is free software; you can redistribute it and/or modify it under the
* terms of the GNU General Public License, see the file COPYING.
*/
static uint32_t crc; /* crc on uncompressed file data */
/* ===========================================================================
@ -2369,7 +2209,7 @@ static int zip(int in, int out)
put_32bit(time_stamp);
/* Write deflated file to zip file */
crc = updcrc(0, 0);
crc = 0;
bi_init(out);
ct_init(&attr, &method);
@ -2388,25 +2228,24 @@ static int zip(int in, int out)
return 0;
}
/* ===========================================================================
* Read a new buffer from the current input file, perform end-of-line
* translation, and update the crc and input file size.
* IN assertion: size >= 2 (for end-of-line translation)
*/
static int file_read(char *buf, unsigned size)
static unsigned file_read(void *buf, unsigned size)
{
unsigned len;
Assert(insize == 0, "inbuf not empty");
len = read(ifd, buf, size);
if (len == (unsigned) (-1) || len == 0)
return (int) len;
if (len == (unsigned)(-1) || len == 0)
return len;
crc = updcrc((uch *) buf, len);
isize += (ulg) len;
return (int) len;
crc = ~updcrc((uch *) buf, len);
isize += len;
return len;
}
/* ===========================================================================
@ -2418,6 +2257,7 @@ static void flush_outbuf(void)
if (outcnt == 0)
return;
write_buf(ofd, (char *) outbuf, outcnt);
xwrite(ofd, (char *) outbuf, outcnt);
outcnt = 0;
}