WebSVN – pentevo – Blame – /tools/mhmt/src/mhmt-depack-megalz.c

Rev	Author	Line No.	Line
969	dimkam	1	// this is not a code to be separately compiled!
		2	// instead, it is included in mhmt-depack.c several times and depends on existing at include moment #define's to generate some compiling code
		3	//
		4	// // example defines:
		5	//#define DPK_CHECK // check input stream for consistency
		6	//#define DPK_DEPACK // do depacking
		7	//#define DPK_REPERR // report errors via printf
		8	{
		9	ULONG check;
		10	ULONG byte,bits,bitlen;
		11	LONG disp;
		12	ULONG length;
		13
		14	ULONG stop;
		15
		16
		17	ULONG success = 1;
		18
		19
		20
		21
		22
		23	// rewind input stream
		24	//
		25	check = depack_getbyte(DEPACK_GETBYTE_REWIND);
		26	#ifdef DPK_CHECK
		27	if( 0xFFFFFFFF == check )
		28	{
		29	#ifdef DPK_REPERR
		30	printf("mhmt-depack-megalz.c:{} - Can't rewind input stream!\n");
		31	#endif
		32	return 0;
		33	}
		34	#endif
		35
		36
		37	// first byte of input stream goes to the output unchanged
		38	//
		39	byte = depack_getbyte(DEPACK_GETBYTE_NEXT);
		40	#ifdef DPK_CHECK
		41	if( 0xFFFFFFFF == byte )
		42	{
		43	NO_BYTE:
		44	#ifdef DPK_REPERR
		45	printf("mhmt-depack-megalz.c:{} - Can't get byte from input stream!\n");
		46	#endif
		47	return 0;
		48	}
		49	#endif
		50
		51	#ifdef DPK_DEPACK
		52	success = success && depack_outbyte( (UBYTE)(0x00FF&byte), DEPACK_OUTBYTE_ADD );
		53	#endif
		54
		55
		56	#ifdef DPK_CHECK
		57	#ifdef DPK_REPERR
		58	#endif
		59	#endif
		60	// next is byte to the bitstream
		61	//
		62	check = depack_getbits(8,DEPACK_GETBITS_FORCE);
		63	#ifdef DPK_CHECK
		64	if( 0xFFFFFFFF == check )
		65	{
		66	NO_BITS:
		67	#ifdef DPK_REPERR
		68	printf("mhmt-depack-megalz.c:{} - Can't get bits from input stream!\n");
		69	#endif
		70	return 0;
		71	}
		72	#endif
		73
		74
		75
		76	// now normal depacking loop
		77	//
		78	stop = 0;
		79	while( (!stop) && success )
		80	{
		81	bits = depack_getbits(1,DEPACK_GETBITS_NEXT);
		82	#ifdef DPK_CHECK
		83	if( 0xFFFFFFFF == bits ) goto NO_BITS;
		84	#endif
		85
		86	if( 1&bits ) // %1<byte>
		87	{
		88	byte = depack_getbyte(DEPACK_GETBYTE_NEXT);
		89	#ifdef DPK_CHECK
		90	if( 0xFFFFFFFF == byte ) goto NO_BYTE;
		91	#endif
		92
		93	#ifdef DPK_DEPACK
		94	success = success && depack_outbyte( (UBYTE)(0x00FF&byte), DEPACK_OUTBYTE_ADD );
		95	#endif
		96	}
		97	else // %0xx
		98	{
		99	bits = depack_getbits(2,DEPACK_GETBITS_NEXT);
		100	#ifdef DPK_CHECK
		101	if( 0xFFFFFFFF == bits ) goto NO_BITS;
		102	#endif
		103
		104	switch( 0x03 & bits )
		105	{
		106	case 0x00: // %000xxx
		107
		108	bits = depack_getbits(3,DEPACK_GETBITS_NEXT);
		109	#ifdef DPK_CHECK
		110	if( 0xFFFFFFFF == bits ) goto NO_BITS;
		111	#endif
		112
		113	disp = (-8) \| (bits&0x07); // FFFFFFF8..FFFFFFFF (-8..-1)
		114	#ifdef DPK_CHECK
		115	if( (ULONG)(-disp) > wrk.maxwin )
		116	{
		117	WRONG_DISP:
		118	#ifdef DPK_REPERR
		119	printf("mhmt-depack-megalz.c:{} - Wrong lookback displacement of %d, greater than maxwin\n",(-disp) );
		120	#endif
		121	return 0;
		122	}
		123	#endif
		124
		125	#ifdef DPK_DEPACK
		126	success = success && depack_repeat(disp,1);
		127	#endif
		128	break;
		129
		130
		131	case 0x01: // %001
		132
		133	byte = depack_getbyte(DEPACK_GETBYTE_NEXT);
		134	#ifdef DPK_CHECK
		135	if( 0xFFFFFFFF == byte ) goto NO_BYTE;
		136	#endif
		137
		138	disp = (-256) \| (0x00FF&byte); // -1..-256
		139	#ifdef DPK_CHECK
		140	if( (ULONG)(-disp) > wrk.maxwin ) goto WRONG_DISP;
		141	#endif
		142
		143	#ifdef DPK_DEPACK
		144	success = success && depack_repeat(disp,2);
		145	#endif
		146	break;
		147
		148
		149	case 0x02: // %010
		150
		151	length = 3;
		152	FAR_DISP:
		153	bits = depack_getbits(1,DEPACK_GETBITS_NEXT);
		154	#ifdef DPK_CHECK
		155	if( 0xFFFFFFFF == bits ) goto NO_BITS;
		156	#endif
		157	if( !(1&bits) ) // -1..-256
		158	{
		159	byte = depack_getbyte(DEPACK_GETBYTE_NEXT);
		160	#ifdef DPK_CHECK
		161	if( 0xFFFFFFFF == byte ) goto NO_BYTE;
		162	#endif
		163	disp = (-256) \| (0x00FF&byte); // -1..-256
		164	#ifdef DPK_CHECK
		165	if( (ULONG)(-disp) > wrk.maxwin ) goto WRONG_DISP;
		166	#endif
		167
		168	#ifdef DPK_DEPACK
		169	success = success && depack_repeat(disp,length);
		170	#endif
		171	}
		172	else // -257..-4352
		173	{
		174	bits = depack_getbits(4,DEPACK_GETBITS_NEXT);
		175	#ifdef DPK_CHECK
		176	if( 0xFFFFFFFF == bits ) goto NO_BITS;
		177	#endif
		178	byte = depack_getbyte(DEPACK_GETBYTE_NEXT);
		179	#ifdef DPK_CHECK
		180	if( 0xFFFFFFFF == byte ) goto NO_BYTE;
		181	#endif
		182	disp = ( ((-16)\|(15&bits)) - 1 )*0x100 + byte;
		183	#ifdef DPK_CHECK
		184	if( (ULONG)(-disp) > wrk.maxwin ) goto WRONG_DISP;
		185	#endif
		186
		187	#ifdef DPK_DEPACK
		188	success = success && depack_repeat(disp,length);
		189	#endif
		190	}
		191
		192	break;
		193
		194
		195	case 0x03: // %011 - variable length
		196
		197	bitlen = 0;
		198	do
		199	{
		200	bits = depack_getbits(1,DEPACK_GETBITS_NEXT);
		201	#ifdef DPK_CHECK
		202	if( 0xFFFFFFFF == bits ) goto NO_BITS;
		203	#endif
		204	bitlen++;
		205
		206	} while ( !(1&bits) );
		207
		208	if( bitlen==9 ) // happy final! WARNING: does not check whether there is remaining of input stream left unused!
		209	{
		210	stop = 1;
		211	break; // exit switch(){}
		212	}
		213	#ifdef DPK_CHECK
		214	if( bitlen>7 )
		215	{
		216	#ifdef DPK_REPERR
		217	printf("mhmt-depack-megalz.c:{} - Wrong LZ code\n");
		218	#endif
		219	return 0;
		220	}
		221	#endif
		222	bits = depack_getbits(bitlen,DEPACK_GETBITS_NEXT);
		223	#ifdef DPK_CHECK
		224	if( 0xFFFFFFFF == bits ) goto NO_BITS;
		225	#endif
		226	length = 2 + (1<<bitlen) + ( bits & ((1<<bitlen)-1) );
		227	#ifdef DPK_CHECK
		228	if( length>255 )
		229	{
		230	#ifdef DPK_REPERR
		231	printf("mhmt-depack-megalz.c:{} - Wrong LZ code\n");
		232	#endif
		233	return 0;
		234	}
		235	#endif
		236	goto FAR_DISP;
		237
		238	break;
		239	}
		240	}
		241
		242	}
		243
		244	return success;
		245	}

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(root)/tools/mhmt/src/mhmt-depack-megalz.c – Rev 969