kitty-gridlock/src/bunzip.h

/* vi: set sw=4 ts=4: */
/*	Small bzip2 deflate implementation, by Rob Landley (rob@landley.net).

	Based on bzip2 decompression code by Julian R Seward (jseward@acm.org),
	which also acknowledges contributions by Mike Burrows, David Wheeler,
	Peter Fenwick, Alistair Moffat, Radford Neal, Ian H. Witten,
	Robert Sedgewick, and Jon L. Bentley.

	This code is licensed under the LGPLv2:
		LGPL (http://www.gnu.org/copyleft/lgpl.html
*/

/*
	Size and speed optimizations by Manuel Novoa III  (mjn3@codepoet.org).

	More efficient reading of huffman codes, a streamlined read_bunzip()
	function, and various other tweaks.  In (limited) tests, approximately
	20% faster than bzcat on x86 and about 10% faster on arm.

	Note that about 2/3 of the time is spent in read_unzip() reversing
	the Burrows-Wheeler transformation.  Much of that time is delay
	resulting from cache misses.

	I would ask that anyone benefiting from this work, especially those
	using it in commercial products, consider making a donation to my local
	non-profit hospice organization (see www.hospiceacadiana.com) in the
    name of the woman I loved, Toni W. Hagan, who passed away Feb. 12, 2003.

	Manuel
 */

/* Modified by Macoy Madson:
   - Give no errors with a C++ compiler (all -fpermissive errors)
   - Add header file
*/

#include <setjmp.h>

/* Constants for huffman coding */
#define MAX_GROUPS			6
#define GROUP_SIZE   		50		/* 64 would have been more efficient */
#define MAX_HUFCODE_BITS 	20		/* Longest huffman code allowed */
#define MAX_SYMBOLS 		258		/* 256 literals + RUNA + RUNB */
#define SYMBOL_RUNA			0
#define SYMBOL_RUNB			1

/* Status return values */
#define RETVAL_OK						0
#define RETVAL_LAST_BLOCK				(-1)
#define RETVAL_NOT_BZIP_DATA			(-2)
#define RETVAL_UNEXPECTED_INPUT_EOF		(-3)
#define RETVAL_UNEXPECTED_OUTPUT_EOF	(-4)
#define RETVAL_DATA_ERROR				(-5)
#define RETVAL_OUT_OF_MEMORY			(-6)
#define RETVAL_OBSOLETE_INPUT			(-7)

/* Other housekeeping constants */
#define IOBUF_SIZE			4096

/* This is what we know about each huffman coding group */
struct group_data {
	/* We have an extra slot at the end of limit[] for a sentinal value. */
	int limit[MAX_HUFCODE_BITS+1],base[MAX_HUFCODE_BITS],permute[MAX_SYMBOLS];
	int minLen, maxLen;
};

/* Structure holding all the housekeeping data, including IO buffers and
   memory that persists between calls to bunzip */
typedef struct {
	/* State for interrupting output loop */
	int writeCopies,writePos,writeRunCountdown,writeCount,writeCurrent;
	/* I/O tracking data (file handles, buffers, positions, etc.) */
	int in_fd,out_fd,inbufCount,inbufPos /*,outbufPos*/;
	unsigned char *inbuf /*,*outbuf*/;
	unsigned int inbufBitCount, inbufBits;
	/* The CRC values stored in the block header and calculated from the data */
	unsigned int crc32Table[256],headerCRC, totalCRC, writeCRC;
	/* Intermediate buffer and its size (in bytes) */
	unsigned int *dbuf, dbufSize;
	/* These things are a bit too big to go on the stack */
	unsigned char selectors[32768];			/* nSelectors=15 bits */
	struct group_data groups[MAX_GROUPS];	/* huffman coding tables */
	/* For I/O error handling */
	jmp_buf jmpbuf;
} bunzip_data;

/* Allocate the structure, read file header.  If in_fd==-1, inbuf must contain
   a complete bunzip file (len bytes long).  If in_fd!=-1, inbuf and len are
   ignored, and data is read from file handle into temporary buffer. */
int start_bunzip(bunzip_data **bdp, int in_fd, char *inbuf, int len);

/* Undo burrows-wheeler transform on intermediate buffer to produce output.
   If start_bunzip was initialized with out_fd=-1, then up to len bytes of
   data are written to outbuf.  Return value is number of bytes written or
   error (all errors are negative numbers).  If out_fd!=-1, outbuf and len
   are ignored, data is written to out_fd and return is RETVAL_OK or error.
*/
int read_bunzip(bunzip_data *bd, char *outbuf, int len);