unzip.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.

    8193, 12289, 16385, 24577
};
static const extra_bits_t cpdext[] = {  /* Extra bits for distance 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
};
/* Tables for deflate from PKZIP's appnote.txt. */
static const extra_bits_t border[] = {  /* Order of the bit length code lengths */
    16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15
};

/*
 * decompress an inflated block
 * e: last block flag
 *
 * GLOBAL VARIABLES: bb, kk,
 */
static int inflate_block(int *e)
{
	unsigned t;			/* block type */
	register unsigned long b;			/* bit buffer */
	register unsigned k;		/* number of bits in bit buffer */

	/* make local bit buffer */
	b = bb;
	k = bk;

	/* read in last block bit */
	while (k < 1) {
		b |= ((unsigned long)fgetc(in_file)) << k;
		k += 8;
	}
	*e = (int) b & 1;
	b >>= 1;
	k -= 1;

	/* read in block type */
	while (k < 2) {
		b |= ((unsigned long)fgetc(in_file)) << k;
		k += 8;
	}
	t = (unsigned) b & 3;
	b >>= 2;
	k -= 2;

	/* restore the global bit buffer */
	bb = b;
	bk = k;

	/* inflate that block type */
	switch (t) {
	case 0:	/* Inflate stored */
		{
			unsigned long n;			/* number of bytes in block */
			unsigned long w;			/* current window position */
			register unsigned long b_stored;			/* bit buffer */
			register unsigned long k_stored;		/* number of bits in bit buffer */

			/* make local copies of globals */
			b_stored = bb;				/* initialize bit buffer */
			k_stored = bk;
			w = outcnt;			/* initialize window position */

			/* go to byte boundary */
			n = k_stored & 7;
			b_stored >>= n;
			k_stored -= n;

			/* get the length and its complement */
			while (k_stored < 16) {
				b_stored |= ((unsigned long)fgetc(in_file)) << k_stored;
				k_stored += 8;
			}
			n = ((unsigned) b_stored & 0xffff);
			b_stored >>= 16;
			k_stored -= 16;
			while (k_stored < 16) {
				b_stored |= ((unsigned long)fgetc(in_file)) << k_stored;
				k_stored += 8;
			}
			if (n != (unsigned) ((~b_stored) & 0xffff)) {
				return 1;		/* error in compressed data */
			}
			b_stored >>= 16;
			k_stored -= 16;

			/* read and output the compressed data */
			while (n--) {
				while (k_stored < 8) {
					b_stored |= ((unsigned long)fgetc(in_file)) << k_stored;
					k_stored += 8;
				}
				window[w++] = (unsigned char) b_stored;
				if (w == (unsigned long)WSIZE) {
					outcnt=(w),
					flush_window();
					w = 0;
				}
				b_stored >>= 8;
				k_stored -= 8;
			}

			/* restore the globals from the locals */
			outcnt = w;			/* restore global window pointer */
			bb = b_stored;				/* restore global bit buffer */
			bk = k_stored;
			return 0;
		}
	case 1:	/* Inflate fixed 
			 * decompress an inflated type 1 (fixed Huffman codes) block.  We should
			 * either replace this with a custom decoder, or at least precompute the
			 * Huffman tables.
			 */
		{
			int i;					/* temporary variable */
			huft_t *tl;				/* literal/length code table */
			huft_t *td;				/* distance code table */
			int bl;					/* lookup bits for tl */
			int bd;					/* lookup bits for td */
			unsigned int l[288];	/* length list for huft_build */

			/* set up literal table */
			for (i = 0; i < 144; i++) {
				l[i] = 8;
			}
			for (; i < 256; i++) {
				l[i] = 9;
			}
			for (; i < 280; i++) {
				l[i] = 7;
			}
			for (; i < 288; i++) {	/* make a complete, but wrong code set */
				l[i] = 8;
			}
			bl = 7;
			if ((i = huft_build(l, 288, 257, cplens, cplext, &tl, &bl)) != 0) {
				return i;
			}

			/* set up distance table */
			for (i = 0; i < 30; i++) {	/* make an incomplete code set */
				l[i] = 5;
			}
			bd = 5;
			if ((i = huft_build(l, 30, 0, cpdist, cpdext, &td, &bd)) > 1) {
				huft_free(tl);
				return i;
			}

			/* decompress until an end-of-block code */
			if (inflate_codes(tl, td, bl, bd))
				return 1;

			/* free the decoding tables, return */
			huft_free(tl);
			huft_free(td);
			return 0;
		}
	case 2:	/* Inflate dynamic */
		{
			const int dbits = 6;					/* bits in base distance lookup table */
			const int lbits = 9;					/* bits in base literal/length lookup table */

			int i;						/* temporary variables */
			unsigned j;
			unsigned l;					/* last length */
			unsigned m;					/* mask for bit lengths table */
			unsigned n;					/* number of lengths to get */
			huft_t *tl;			/* literal/length code table */
			huft_t *td;			/* distance code table */
			int bl;						/* lookup bits for tl */
			int bd;						/* lookup bits for td */
			unsigned nb;				/* number of bit length codes */
			unsigned nl;				/* number of literal/length codes */
			unsigned nd;				/* number of distance codes */

			unsigned ll[286 + 30];		/* literal/length and distance code lengths */
			register unsigned long b_dynamic;	/* bit buffer */
			register unsigned k_dynamic;		/* number of bits in bit buffer */

			/* make local bit buffer */
			b_dynamic = bb;
			k_dynamic = bk;

			/* read in table lengths */
			while (k_dynamic < 5) {
				b_dynamic |= ((unsigned long)fgetc(in_file)) << k_dynamic;
				k_dynamic += 8;
			}
			nl = 257 + ((unsigned) b_dynamic & 0x1f);	/* number of literal/length codes */
			b_dynamic >>= 5;
			k_dynamic -= 5;
			while (k_dynamic < 5) {
				b_dynamic |= ((unsigned long)fgetc(in_file)) << k_dynamic;
				k_dynamic += 8;
			}
			nd = 1 + ((unsigned) b_dynamic & 0x1f);	/* number of distance codes */
			b_dynamic >>= 5;
			k_dynamic -= 5;
			while (k_dynamic < 4) {
				b_dynamic |= ((unsigned long)fgetc(in_file)) << k_dynamic;
				k_dynamic += 8;
			}
			nb = 4 + ((unsigned) b_dynamic & 0xf);	/* number of bit length codes */
			b_dynamic >>= 4;
			k_dynamic -= 4;
			if (nl > 286 || nd > 30) {
				return 1;	/* bad lengths */
			}

			/* read in bit-length-code lengths */
			for (j = 0; j < nb; j++) {
				while (k_dynamic < 3) {
					b_dynamic |= ((unsigned long)fgetc(in_file)) << k_dynamic;
					k_dynamic += 8;
				}
				ll[border[j]] = (unsigned) b_dynamic & 7;
				b_dynamic >>= 3;
				k_dynamic -= 3;
			}
			for (; j < 19; j++) {
				ll[border[j]] = 0;
			}

			/* build decoding table for trees--single level, 7 bit lookup */
			bl = 7;
			if ((i = huft_build(ll, 19, 19, NULL, NULL, &tl, &bl)) != 0) {
				if (i == 1) {
					huft_free(tl);
				}
				return i;			/* incomplete code set */
			}

			/* read in literal and distance code lengths */
			n = nl + nd;
			m = mask_bits[bl];
			i = l = 0;
			while ((unsigned) i < n) {
				while (k_dynamic < (unsigned) bl) {
					b_dynamic |= ((unsigned long)fgetc(in_file)) << k_dynamic;
					k_dynamic += 8;
				}
				j = (td = tl + ((unsigned) b_dynamic & m))->b;
				b_dynamic >>= j;
				k_dynamic -= j;
				j = td->v.n;
				if (j < 16) {			/* length of code in bits (0..15) */
					ll[i++] = l = j;	/* save last length in l */
				}
				else if (j == 16) {		/* repeat last length 3 to 6 times */
					while (k_dynamic < 2) {
						b_dynamic |= ((unsigned long)fgetc(in_file)) << k_dynamic;
						k_dynamic += 8;
					}
					j = 3 + ((unsigned) b_dynamic & 3);
					b_dynamic >>= 2;
					k_dynamic -= 2;
					if ((unsigned) i + j > n) {
						return 1;
					}
					while (j--) {
						ll[i++] = l;
					}
				} else if (j == 17) {	/* 3 to 10 zero length codes */
					while (k_dynamic < 3) {
						b_dynamic |= ((unsigned long)fgetc(in_file)) << k_dynamic;
						k_dynamic += 8;
					}
					j = 3 + ((unsigned) b_dynamic & 7);
					b_dynamic >>= 3;
					k_dynamic -= 3;
					if ((unsigned) i + j > n) {
						return 1;
					}
					while (j--) {
						ll[i++] = 0;
					}
					l = 0;
				} else {		/* j == 18: 11 to 138 zero length codes */
					while (k_dynamic < 7) {
						b_dynamic |= ((unsigned long)fgetc(in_file)) << k_dynamic;
						k_dynamic += 8;
					}
					j = 11 + ((unsigned) b_dynamic & 0x7f);
					b_dynamic >>= 7;
					k_dynamic -= 7;
					if ((unsigned) i + j > n) {
						return 1;
					}
					while (j--) {
						ll[i++] = 0;
					}
					l = 0;
				}
			}

			/* free decoding table for trees */
			huft_free(tl);

			/* restore the global bit buffer */
			bb = b_dynamic;
			bk = k_dynamic;

			/* build the decoding tables for literal/length and distance codes */
			bl = lbits;
			if ((i = huft_build(ll, nl, 257, cplens, cplext, &tl, &bl)) != 0) {
				if (i == 1) {
					error_msg("Incomplete literal tree");
					huft_free(tl);
				}
				return i;			/* incomplete code set */
			}
			bd = dbits;
			if ((i = huft_build(ll + nl, nd, 0, cpdist, cpdext, &td, &bd)) != 0) {
				if (i == 1) {
					error_msg("incomplete distance tree");
					huft_free(td);
				}
				huft_free(tl);
				return i;			/* incomplete code set */
			}

			/* decompress until an end-of-block code */
			if (inflate_codes(tl, td, bl, bd))
				return 1;

			/* free the decoding tables, return */
			huft_free(tl);
			huft_free(td);
			return 0;
		}
	default:
		/* bad block type */
		return 2;
	}
}

/*
 * decompress an inflated entry
 *
 * GLOBAL VARIABLES: outcnt, bk, bb, hufts, inptr
 */
extern int inflate(FILE *in, FILE *out)
{
	int e;				/* last block flag */
	int r;				/* result code */
	unsigned h = 0;		/* maximum struct huft's malloc'ed */

	/* initialize window, bit buffer */
	outcnt = 0;
	bk = 0;
	bb = 0;

	in_file = in;
	out_file = out;

	/* Allocate all global buffers (for DYN_ALLOC option) */
	window = xmalloc((size_t)(((2L*WSIZE)+1L)*sizeof(unsigned char)));
	bytes_out = 0L;

	/* Create the crc table */
	make_crc_table();

	/* decompress until the last block */
	do {
		hufts = 0;
		if ((r = inflate_block(&e)) != 0) {
			return r;
		}
		if (hufts > h) {
			h = hufts;
		}
	} while (!e);

	/* Undo too much lookahead. The next read will be byte aligned so we
	 * can discard unused bits in the last meaningful byte.
	 */
	while (bk >= 8) {
		bk -= 8;
		ungetc((bb << bk), in_file);
	}

	/* flush out window */
	flush_window();
	free(window);
	free(crc_table);

	/* return success */
	return 0;
}

/* ===========================================================================
 * Unzip in to out.  This routine works on gzip files only.
 *
 * IN assertions: the buffer inbuf contains already the beginning of
 *   the compressed data, from offsets inptr to insize-1 included.
 *   The magic header has already been checked. The output buffer is cleared.
 * in, out: input and output file descriptors
 */
extern int unzip(FILE *l_in_file, FILE *l_out_file)
{
	unsigned char buf[8];	/* extended local header */
	unsigned char flags;	/* compression flags */
	typedef void (*sig_type) (int);
	unsigned short i;
	unsigned char magic [2];

	if (signal(SIGINT, SIG_IGN) != SIG_IGN) {
		(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

	magic [0] = fgetc(l_in_file);
	magic [1] = fgetc(l_in_file);
	
#ifdef CONFIG_FEATURE_UNCOMPRESS
	/* Magic header for compress files, 1F 9d = \037\235 */
	if (( magic [0] == 0x1F ) && ( magic [1] == 0x9d)) {
		return uncompress ( l_in_file, l_out_file );
	}
#endif

	/* Magic header for gzip files, 1F 8B = \037\213 */
	if (( magic [0] != 0x1F ) || ( magic [1] != 0x8b)) {
		error_msg("Invalid gzip magic");
		return EXIT_FAILURE;
	}

	/* Check the compression method */
	if (fgetc(l_in_file) != 8) {
		error_msg("Unknown compression method");
		return(-1);
	}

	flags = (unsigned char) fgetc(l_in_file);

	/* Ignore time stamp(4), extra flags(1), OS type(1) */
	for (i = 0; i < 6; i++) {
		fgetc(l_in_file);
	}

	if (flags & 0x04) {
		/* bit 2 set: extra field present */
		const unsigned short extra = fgetc(l_in_file) + (fgetc(l_in_file) << 8);

		for (i = 0; i < extra; i++) {
			fgetc(l_in_file);
		}
	}

	/* Discard original name if any */
	if (flags & 0x08) {
		/* bit 3 set: original file name present */
		while (fgetc(l_in_file) != 0);	/* null */
	}

	/* Discard file comment if any */
	if (flags & 0x10) {
		/* bit 4 set: file comment present */
		while (fgetc(l_in_file) != 0);	/* null */
	}

	/* Decompress */
	if (inflate(l_in_file, l_out_file) != 0) {
		error_msg("invalid compressed data--format violated");
	}

	/* Get the crc and original length
	 * crc32  (see algorithm.doc)
	 * uncompressed input size modulo 2^32
	 */
	fread(buf, 1, 8, l_in_file);

	/* Validate decompression - crc */
	if ((unsigned int)((buf[0] | (buf[1] << 8)) |((buf[2] | (buf[3] << 8)) << 16)) != (crc ^ 0xffffffffL)) {
		error_msg("invalid compressed data--crc error");
	}
	/* Validate decompression - size */
	if (((buf[4] | (buf[5] << 8)) |((buf[6] | (buf[7] << 8)) << 16)) != (unsigned long) bytes_out) {
		error_msg("invalid compressed data--length error");
	}

	return 0;
}

/*
 * This needs access to global variables window and crc_table, so its not in its own file.
 */
extern void gz_close(int gunzip_pid)
{
	if (kill(gunzip_pid, SIGTERM) == -1) {
		error_msg_and_die("***  Couldnt kill old gunzip process *** aborting");
	}

	if (waitpid(gunzip_pid, NULL, 0) == -1) {
		printf("Couldnt wait ?");
	}

	free(window);
	free(crc_table);
}