gzip.c

这是一个SIGMA方案的PMP播放器的UCLINUX程序,可播放DVD,VCD,CD MP3...有很好的参考价值.

	if (foreground) {
		(void) signal(SIGINT, (sig_type) abort_gzip);
	}
#ifdef SIGTERM
	if (signal(SIGTERM, SIG_IGN) != SIG_IGN) {
		(void) signal(SIGTERM, (sig_type) abort_gzip);
	}
#endif
#ifdef SIGHUP
	if (signal(SIGHUP, SIG_IGN) != SIG_IGN) {
		(void) signal(SIGHUP, (sig_type) abort_gzip);
	}
#endif

	strncpy(z_suffix, Z_SUFFIX, sizeof(z_suffix) - 1);
	z_len = strlen(z_suffix);

	/* Allocate all global buffers (for DYN_ALLOC option) */
	ALLOC(uch, inbuf, INBUFSIZ + INBUF_EXTRA);
	ALLOC(uch, outbuf, OUTBUFSIZ + OUTBUF_EXTRA);
	ALLOC(ush, d_buf, DIST_BUFSIZE);
	ALLOC(uch, window, 2L * WSIZE);
	ALLOC(ush, tab_prefix, 1L << BITS);

	clear_bufs();
	part_nb = 0;

	if (optind == argc) {
		time_stamp = 0;
		ifile_size = -1L;
		zip(STDIN_FILENO, STDOUT_FILENO);
	} else {
		int i;

		for (i = optind; i < argc; i++) {
			char *path = NULL;

			if (strcmp(argv[i], "-") == 0) {
				time_stamp = 0;
				ifile_size = -1L;
				inFileNum = STDIN_FILENO;
				outFileNum = STDOUT_FILENO;
			} else {
				inFileNum = open(argv[i], O_RDONLY);
				if (inFileNum < 0 || fstat (inFileNum, &statBuf) < 0)
					perror_msg_and_die("%s", argv[i]);
				time_stamp = statBuf.st_ctime;
				ifile_size = statBuf.st_size;

				if (!tostdout) {
					path = xmalloc(strlen(argv[i]) + 4);
					strcpy(path, argv[i]);
					strcat(path, ".gz");

					/* Open output file */
#if (__GLIBC__ >= 2) && (__GLIBC_MINOR__ >= 1)
					outFileNum = open(path, O_RDWR | O_CREAT | O_EXCL | O_NOFOLLOW);
#else
					outFileNum = open(path, O_RDWR | O_CREAT | O_EXCL);
#endif
					if (outFileNum < 0) {
						perror_msg("%s", path);
						free(path);
						continue;
					}

					/* Set permissions on the file */
					fchmod(outFileNum, statBuf.st_mode);
				} else
					outFileNum = STDOUT_FILENO;
			}

			if (path == NULL && isatty(outFileNum) && force == 0) {
				error_msg("compressed data not written to a terminal. Use -f to force compression.");
				free(path);
				continue;
			}

			result = zip(inFileNum, outFileNum);

			if (path != NULL) {
				close (inFileNum);
				close (outFileNum);

				/* Delete the original file */
				if (result == OK)
					delFileName = argv[i];
				else
					delFileName = path;

				if (unlink(delFileName) < 0)
					perror_msg("%s", delFileName);
			}

			free(path);
		}
	}

	return(exit_code);
}

/* trees.c -- output deflated data using Huffman coding
 * Copyright (C) 1992-1993 Jean-loup Gailly
 * This is free software; you can redistribute it and/or modify it under the
 * terms of the GNU General Public License, see the file COPYING.
 */

/*
 *  PURPOSE
 *
 *      Encode various sets of source values using variable-length
 *      binary code trees.
 *
 *  DISCUSSION
 *
 *      The PKZIP "deflation" process uses several Huffman trees. The more
 *      common source values are represented by shorter bit sequences.
 *
 *      Each code tree is stored in the ZIP file in a compressed form
 *      which is itself a Huffman encoding of the lengths of
 *      all the code strings (in ascending order by source values).
 *      The actual code strings are reconstructed from the lengths in
 *      the UNZIP process, as described in the "application note"
 *      (APPNOTE.TXT) distributed as part of PKWARE's PKZIP program.
 *
 *  REFERENCES
 *
 *      Lynch, Thomas J.
 *          Data Compression:  Techniques and Applications, pp. 53-55.
 *          Lifetime Learning Publications, 1985.  ISBN 0-534-03418-7.
 *
 *      Storer, James A.
 *          Data Compression:  Methods and Theory, pp. 49-50.
 *          Computer Science Press, 1988.  ISBN 0-7167-8156-5.
 *
 *      Sedgewick, R.
 *          Algorithms, p290.
 *          Addison-Wesley, 1983. ISBN 0-201-06672-6.
 *
 *  INTERFACE
 *
 *      void ct_init (ush *attr, int *methodp)
 *          Allocate the match buffer, initialize the various tables and save
 *          the location of the internal file attribute (ascii/binary) and
 *          method (DEFLATE/STORE)
 *
 *      void ct_tally (int dist, int lc);
 *          Save the match info and tally the frequency counts.
 *
 *      long flush_block (char *buf, ulg stored_len, int eof)
 *          Determine the best encoding for the current block: dynamic trees,
 *          static trees or store, and output the encoded block to the zip
 *          file. Returns the total compressed length for the file so far.
 *
 */

/* ===========================================================================
 * Constants
 */

#define MAX_BITS 15
/* All codes must not exceed MAX_BITS bits */

#define MAX_BL_BITS 7
/* Bit length codes must not exceed MAX_BL_BITS bits */

#define LENGTH_CODES 29
/* number of length codes, not counting the special END_BLOCK code */

#define LITERALS  256
/* number of literal bytes 0..255 */

#define END_BLOCK 256
/* end of block literal code */

#define L_CODES (LITERALS+1+LENGTH_CODES)
/* number of Literal or Length codes, including the END_BLOCK code */

#define D_CODES   30
/* number of distance codes */

#define BL_CODES  19
/* number of codes used to transfer the bit lengths */

typedef uch extra_bits_t;

/* extra bits for each length code */
static const extra_bits_t extra_lbits[LENGTH_CODES]    
	= { 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4,
		4, 4, 5, 5, 5, 5, 0 };

/* extra bits for each distance code */
static const extra_bits_t extra_dbits[D_CODES]    
	= { 0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6, 7, 7, 8, 8, 9, 9,
		10, 10, 11, 11, 12, 12, 13, 13 };

/* extra bits for each bit length code */
static const extra_bits_t extra_blbits[BL_CODES]  
= { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 3, 7 };

#define STORED_BLOCK 0
#define STATIC_TREES 1
#define DYN_TREES    2
/* The three kinds of block type */

#ifndef LIT_BUFSIZE
#  ifdef SMALL_MEM
#    define LIT_BUFSIZE  0x2000
#  else
#  ifdef MEDIUM_MEM
#    define LIT_BUFSIZE  0x4000
#  else
#    define LIT_BUFSIZE  0x8000
#  endif
#  endif
#endif
#ifndef DIST_BUFSIZE
#  define DIST_BUFSIZE  LIT_BUFSIZE
#endif
/* Sizes of match buffers for literals/lengths and distances.  There are
 * 4 reasons for limiting LIT_BUFSIZE to 64K:
 *   - frequencies can be kept in 16 bit counters
 *   - if compression is not successful for the first block, all input data is
 *     still in the window so we can still emit a stored block even when input
 *     comes from standard input.  (This can also be done for all blocks if
 *     LIT_BUFSIZE is not greater than 32K.)
 *   - if compression is not successful for a file smaller than 64K, we can
 *     even emit a stored file instead of a stored block (saving 5 bytes).
 *   - creating new Huffman trees less frequently may not provide fast
 *     adaptation to changes in the input data statistics. (Take for
 *     example a binary file with poorly compressible code followed by
 *     a highly compressible string table.) Smaller buffer sizes give
 *     fast adaptation but have of course the overhead of transmitting trees
 *     more frequently.
 *   - I can't count above 4
 * The current code is general and allows DIST_BUFSIZE < LIT_BUFSIZE (to save
 * memory at the expense of compression). Some optimizations would be possible
 * if we rely on DIST_BUFSIZE == LIT_BUFSIZE.
 */
#if LIT_BUFSIZE > INBUFSIZ
#error cannot overlay l_buf and inbuf
#endif
#define REP_3_6      16
/* repeat previous bit length 3-6 times (2 bits of repeat count) */
#define REPZ_3_10    17
/* repeat a zero length 3-10 times  (3 bits of repeat count) */
#define REPZ_11_138  18
/* repeat a zero length 11-138 times  (7 bits of repeat count) *//* ===========================================================================
 * Local data
 *//* Data structure describing a single value and its code string. */ typedef struct ct_data {
	union {
		ush freq;				/* frequency count */
		ush code;				/* bit string */
	} fc;
	union {
		ush dad;				/* father node in Huffman tree */
		ush len;				/* length of bit string */
	} dl;
} ct_data;

#define Freq fc.freq
#define Code fc.code
#define Dad  dl.dad
#define Len  dl.len

#define HEAP_SIZE (2*L_CODES+1)
/* maximum heap size */

static ct_data dyn_ltree[HEAP_SIZE];	/* literal and length tree */
static ct_data dyn_dtree[2 * D_CODES + 1];	/* distance tree */

static ct_data static_ltree[L_CODES + 2];

/* The static literal tree. Since the bit lengths are imposed, there is no
 * need for the L_CODES extra codes used during heap construction. However
 * The codes 286 and 287 are needed to build a canonical tree (see ct_init
 * below).
 */

static ct_data static_dtree[D_CODES];

/* The static distance tree. (Actually a trivial tree since all codes use
 * 5 bits.)
 */

static ct_data bl_tree[2 * BL_CODES + 1];

/* Huffman tree for the bit lengths */

typedef struct tree_desc {
	ct_data *dyn_tree;		/* the dynamic tree */
	ct_data *static_tree;	/* corresponding static tree or NULL */
	const extra_bits_t *extra_bits; /* extra bits for each code or NULL */
	int extra_base;				/* base index for extra_bits */
	int elems;					/* max number of elements in the tree */
	int max_length;				/* max bit length for the codes */
	int max_code;				/* largest code with non zero frequency */
} tree_desc;

static tree_desc l_desc =
	{ dyn_ltree, static_ltree, extra_lbits, LITERALS + 1, L_CODES,
		MAX_BITS, 0 };

static tree_desc d_desc =
	{ dyn_dtree, static_dtree, extra_dbits, 0, D_CODES, MAX_BITS, 0 };

static tree_desc bl_desc =
	{ bl_tree, (ct_data *) 0, extra_blbits, 0, BL_CODES, MAX_BL_BITS,
		0 };


static ush bl_count[MAX_BITS + 1];

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

static const uch bl_order[BL_CODES]
= { 16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15 };

/* The lengths of the bit length codes are sent in order of decreasing
 * probability, to avoid transmitting the lengths for unused bit length codes.
 */

static int heap[2 * L_CODES + 1];	/* heap used to build the Huffman trees */
static int heap_len;				/* number of elements in the heap */
static int heap_max;				/* element of largest frequency */

/* The sons of heap[n] are heap[2*n] and heap[2*n+1]. heap[0] is not used.
 * The same heap array is used to build all trees.
 */

static uch depth[2 * L_CODES + 1];

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

static uch length_code[MAX_MATCH - MIN_MATCH + 1];

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

static uch dist_code[512];

/* distance codes. The first 256 values correspond to the distances
 * 3 .. 258, the last 256 values correspond to the top 8 bits of
 * the 15 bit distances.
 */

static int base_length[LENGTH_CODES];

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

static int base_dist[D_CODES];

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

#define l_buf inbuf
/* DECLARE(uch, l_buf, LIT_BUFSIZE);  buffer for literals or lengths */

/* DECLARE(ush, d_buf, DIST_BUFSIZE); buffer for distances */

static uch flag_buf[(LIT_BUFSIZE / 8)];

/* flag_buf is a bit array distinguishing literals from lengths in
 * l_buf, thus indicating the presence or absence of a distance.
 */

static unsigned last_lit;		/* running index in l_buf */
static unsigned last_dist;		/* running index in d_buf */
static unsigned last_flags;		/* running index in flag_buf */
static uch flags;				/* current flags not yet saved in flag_buf */
static uch flag_bit;				/* current bit used in flags */

/* bits are filled in flags starting at bit 0 (least significant).
 * Note: these flags are overkill in the current code since we don't
 * take advantage of DIST_BUFSIZE == LIT_BUFSIZE.
 */

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

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


static ush *file_type;					/* pointer to UNKNOWN, BINARY or ASCII */
static int *file_method;				/* pointer to DEFLATE or STORE */

/* ===========================================================================
 * Local (static) routines in this file.
 */

static void init_block (void);
static void pqdownheap (ct_data * tree, int k);
static void gen_bitlen (tree_desc * desc);
static void gen_codes (ct_data * tree, int max_code);
static void build_tree (tree_desc * desc);
static void scan_tree (ct_data * tree, int max_code);
static void send_tree (ct_data * tree, int max_code);
static int build_bl_tree (void);
static void send_all_trees (int lcodes, int dcodes, int blcodes);
static void compress_block (ct_data * ltree, ct_data * dtree);
static void set_file_type (void);


#ifndef DEBUG
#  define send_code(c, tree) send_bits(tree[c].Code, tree[c].Len)
   /* Send a code of the given tree. c and tree must not have side effects */

#else							/* DEBUG */
#  define send_code(c, tree) \
     { if (verbose>1) fprintf(stderr,"\ncd %3d ",(c)); \
       send_bits(tree[c].Code, tree[c].Len); }
#endif

#define d_code(dist) \
   ((dist) < 256 ? dist_code[dist] : dist_code[256+((dist)>>7)])
/* Mapping from a distance to a distance code. dist is the distance - 1 and