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828 lines
32 KiB
C
828 lines
32 KiB
C
/***************************************************************************
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* lzx.c - LZX decompression routines *
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* ------------------- *
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* *
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* maintainer: Jed Wing <jedwin@ugcs.caltech.edu> *
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* source: modified lzx.c from cabextract v0.5 *
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* notes: This file was taken from cabextract v0.5, which was, *
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* itself, a modified version of the lzx decompression code *
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* from unlzx. *
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* *
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* platforms: In its current incarnation, this file has been tested on *
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* two different Linux platforms (one, redhat-based, with a *
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* 2.1.2 glibc and gcc 2.95.x, and the other, Debian, with *
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* 2.2.4 glibc and both gcc 2.95.4 and gcc 3.0.2). Both were *
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* Intel x86 compatible machines. *
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***************************************************************************/
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/***************************************************************************
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*
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* Copyright(C) Stuart Caie
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
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*
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***************************************************************************/
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#include "precomp.h"
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/* sized types */
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typedef unsigned char UBYTE; /* 8 bits exactly */
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typedef unsigned short UWORD; /* 16 bits (or more) */
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/* some constants defined by the LZX specification */
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#define LZX_MIN_MATCH (2)
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#define LZX_MAX_MATCH (257)
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#define LZX_NUM_CHARS (256)
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#define LZX_BLOCKTYPE_INVALID (0) /* also blocktypes 4-7 invalid */
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#define LZX_BLOCKTYPE_VERBATIM (1)
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#define LZX_BLOCKTYPE_ALIGNED (2)
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#define LZX_BLOCKTYPE_UNCOMPRESSED (3)
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#define LZX_PRETREE_NUM_ELEMENTS (20)
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#define LZX_ALIGNED_NUM_ELEMENTS (8) /* aligned offset tree #elements */
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#define LZX_NUM_PRIMARY_LENGTHS (7) /* this one missing from spec! */
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#define LZX_NUM_SECONDARY_LENGTHS (249) /* length tree #elements */
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/* LZX huffman defines: tweak tablebits as desired */
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#define LZX_PRETREE_MAXSYMBOLS (LZX_PRETREE_NUM_ELEMENTS)
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#define LZX_PRETREE_TABLEBITS (6)
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#define LZX_MAINTREE_MAXSYMBOLS (LZX_NUM_CHARS + 50*8)
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#define LZX_MAINTREE_TABLEBITS (12)
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#define LZX_LENGTH_MAXSYMBOLS (LZX_NUM_SECONDARY_LENGTHS+1)
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#define LZX_LENGTH_TABLEBITS (12)
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#define LZX_ALIGNED_MAXSYMBOLS (LZX_ALIGNED_NUM_ELEMENTS)
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#define LZX_ALIGNED_TABLEBITS (7)
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#define LZX_LENTABLE_SAFETY (64) /* we allow length table decoding overruns */
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#define LZX_DECLARE_TABLE(tbl) \
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UWORD tbl##_table[(1<<LZX_##tbl##_TABLEBITS) + (LZX_##tbl##_MAXSYMBOLS<<1)];\
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UBYTE tbl##_len [LZX_##tbl##_MAXSYMBOLS + LZX_LENTABLE_SAFETY]
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struct LZXstate
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{
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UBYTE *window; /* the actual decoding window */
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ULONG window_size; /* window size (32Kb through 2Mb) */
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ULONG actual_size; /* window size when it was first allocated */
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ULONG window_posn; /* current offset within the window */
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ULONG R0, R1, R2; /* for the LRU offset system */
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UWORD main_elements; /* number of main tree elements */
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int header_read; /* have we started decoding at all yet? */
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UWORD block_type; /* type of this block */
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ULONG block_length; /* uncompressed length of this block */
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ULONG block_remaining; /* uncompressed bytes still left to decode */
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ULONG frames_read; /* the number of CFDATA blocks processed */
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LONG intel_filesize; /* magic header value used for transform */
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LONG intel_curpos; /* current offset in transform space */
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int intel_started; /* have we seen any translatable data yet? */
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LZX_DECLARE_TABLE(PRETREE);
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LZX_DECLARE_TABLE(MAINTREE);
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LZX_DECLARE_TABLE(LENGTH);
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LZX_DECLARE_TABLE(ALIGNED);
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};
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/* LZX decruncher */
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/* Microsoft's LZX document and their implementation of the
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* com.ms.util.cab Java package do not concur.
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*
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* In the LZX document, there is a table showing the correlation between
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* window size and the number of position slots. It states that the 1MB
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* window = 40 slots and the 2MB window = 42 slots. In the implementation,
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* 1MB = 42 slots, 2MB = 50 slots. The actual calculation is 'find the
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* first slot whose position base is equal to or more than the required
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* window size'. This would explain why other tables in the document refer
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* to 50 slots rather than 42.
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*
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* The constant NUM_PRIMARY_LENGTHS used in the decompression pseudocode
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* is not defined in the specification.
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*
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* The LZX document does not state the uncompressed block has an
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* uncompressed length field. Where does this length field come from, so
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* we can know how large the block is? The implementation has it as the 24
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* bits following after the 3 blocktype bits, before the alignment
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* padding.
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*
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* The LZX document states that aligned offset blocks have their aligned
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* offset huffman tree AFTER the main and length trees. The implementation
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* suggests that the aligned offset tree is BEFORE the main and length
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* trees.
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*
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* The LZX document decoding algorithm states that, in an aligned offset
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* block, if an extra_bits value is 1, 2 or 3, then that number of bits
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* should be read and the result added to the match offset. This is
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* correct for 1 and 2, but not 3, where just a huffman symbol (using the
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* aligned tree) should be read.
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*
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* Regarding the E8 preprocessing, the LZX document states 'No translation
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* may be performed on the last 6 bytes of the input block'. This is
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* correct. However, the pseudocode provided checks for the *E8 leader*
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* up to the last 6 bytes. If the leader appears between -10 and -7 bytes
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* from the end, this would cause the next four bytes to be modified, at
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* least one of which would be in the last 6 bytes, which is not allowed
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* according to the spec.
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*
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* The specification states that the huffman trees must always contain at
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* least one element. However, many CAB files contain blocks where the
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* length tree is completely empty (because there are no matches), and
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* this is expected to succeed.
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*/
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/* LZX uses what it calls 'position slots' to represent match offsets.
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* What this means is that a small 'position slot' number and a small
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* offset from that slot are encoded instead of one large offset for
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* every match.
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* - position_base is an index to the position slot bases
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* - extra_bits states how many bits of offset-from-base data is needed.
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*/
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static const UBYTE extra_bits[51] = {
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0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6,
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7, 7, 8, 8, 9, 9, 10, 10, 11, 11, 12, 12, 13, 13, 14, 14,
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15, 15, 16, 16, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17,
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17, 17, 17
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};
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static const ULONG position_base[51] = {
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0, 1, 2, 3, 4, 6, 8, 12, 16, 24, 32, 48, 64, 96, 128, 192,
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256, 384, 512, 768, 1024, 1536, 2048, 3072, 4096, 6144, 8192, 12288, 16384, 24576, 32768, 49152,
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65536, 98304, 131072, 196608, 262144, 393216, 524288, 655360, 786432, 917504, 1048576, 1179648, 1310720, 1441792, 1572864, 1703936,
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1835008, 1966080, 2097152
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};
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struct LZXstate *LZXinit(int window)
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{
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struct LZXstate *pState=NULL;
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ULONG wndsize = 1 << window;
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int i, posn_slots;
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/* LZX supports window sizes of 2^15 (32Kb) through 2^21 (2Mb) */
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/* if a previously allocated window is big enough, keep it */
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if (window < 15 || window > 21) return NULL;
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/* allocate state and associated window */
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pState = HeapAlloc(GetProcessHeap(), 0, sizeof(struct LZXstate));
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if (!(pState->window = HeapAlloc(GetProcessHeap(), 0, wndsize)))
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{
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HeapFree(GetProcessHeap(), 0, pState);
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return NULL;
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}
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pState->actual_size = wndsize;
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pState->window_size = wndsize;
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/* calculate required position slots */
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if (window == 20) posn_slots = 42;
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else if (window == 21) posn_slots = 50;
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else posn_slots = window << 1;
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/** alternatively **/
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/* posn_slots=i=0; while (i < wndsize) i += 1 << extra_bits[posn_slots++]; */
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/* initialize other state */
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pState->R0 = pState->R1 = pState->R2 = 1;
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pState->main_elements = LZX_NUM_CHARS + (posn_slots << 3);
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pState->header_read = 0;
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pState->frames_read = 0;
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pState->block_remaining = 0;
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pState->block_type = LZX_BLOCKTYPE_INVALID;
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pState->intel_curpos = 0;
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pState->intel_started = 0;
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pState->window_posn = 0;
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/* initialise tables to 0 (because deltas will be applied to them) */
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for (i = 0; i < LZX_MAINTREE_MAXSYMBOLS; i++) pState->MAINTREE_len[i] = 0;
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for (i = 0; i < LZX_LENGTH_MAXSYMBOLS; i++) pState->LENGTH_len[i] = 0;
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return pState;
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}
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void LZXteardown(struct LZXstate *pState)
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{
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if (pState)
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{
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HeapFree(GetProcessHeap(), 0, pState->window);
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HeapFree(GetProcessHeap(), 0, pState);
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}
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}
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int LZXreset(struct LZXstate *pState)
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{
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int i;
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pState->R0 = pState->R1 = pState->R2 = 1;
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pState->header_read = 0;
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pState->frames_read = 0;
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pState->block_remaining = 0;
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pState->block_type = LZX_BLOCKTYPE_INVALID;
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pState->intel_curpos = 0;
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pState->intel_started = 0;
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pState->window_posn = 0;
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for (i = 0; i < LZX_MAINTREE_MAXSYMBOLS + LZX_LENTABLE_SAFETY; i++) pState->MAINTREE_len[i] = 0;
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for (i = 0; i < LZX_LENGTH_MAXSYMBOLS + LZX_LENTABLE_SAFETY; i++) pState->LENGTH_len[i] = 0;
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return DECR_OK;
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}
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/* Bitstream reading macros:
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*
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* INIT_BITSTREAM should be used first to set up the system
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* READ_BITS(var,n) takes N bits from the buffer and puts them in var
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*
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* ENSURE_BITS(n) ensures there are at least N bits in the bit buffer
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* PEEK_BITS(n) extracts (without removing) N bits from the bit buffer
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* REMOVE_BITS(n) removes N bits from the bit buffer
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*
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* These bit access routines work by using the area beyond the MSB and the
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* LSB as a free source of zeroes. This avoids having to mask any bits.
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* So we have to know the bit width of the bitbuffer variable. This is
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* sizeof(ULONG) * 8, also defined as ULONG_BITS
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*/
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/* number of bits in ULONG. Note: This must be at multiple of 16, and at
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* least 32 for the bitbuffer code to work (ie, it must be able to ensure
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* up to 17 bits - that's adding 16 bits when there's one bit left, or
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* adding 32 bits when there are no bits left. The code should work fine
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* for machines where ULONG >= 32 bits.
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*/
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#define ULONG_BITS (sizeof(ULONG)<<3)
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#define INIT_BITSTREAM do { bitsleft = 0; bitbuf = 0; } while (0)
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#define ENSURE_BITS(n) \
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while (bitsleft < (n)) { \
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bitbuf |= ((inpos[1]<<8)|inpos[0]) << (ULONG_BITS-16 - bitsleft); \
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bitsleft += 16; inpos+=2; \
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}
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#define PEEK_BITS(n) (bitbuf >> (ULONG_BITS - (n)))
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#define REMOVE_BITS(n) ((bitbuf <<= (n)), (bitsleft -= (n)))
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#define READ_BITS(v,n) do { \
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ENSURE_BITS(n); \
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(v) = PEEK_BITS(n); \
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REMOVE_BITS(n); \
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} while (0)
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/* Huffman macros */
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#define TABLEBITS(tbl) (LZX_##tbl##_TABLEBITS)
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#define MAXSYMBOLS(tbl) (LZX_##tbl##_MAXSYMBOLS)
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#define SYMTABLE(tbl) (pState->tbl##_table)
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#define LENTABLE(tbl) (pState->tbl##_len)
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/* BUILD_TABLE(tablename) builds a huffman lookup table from code lengths.
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* In reality, it just calls make_decode_table() with the appropriate
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* values - they're all fixed by some #defines anyway, so there's no point
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* writing each call out in full by hand.
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*/
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#define BUILD_TABLE(tbl) \
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if (make_decode_table( \
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MAXSYMBOLS(tbl), TABLEBITS(tbl), LENTABLE(tbl), SYMTABLE(tbl) \
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)) { return DECR_ILLEGALDATA; }
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/* READ_HUFFSYM(tablename, var) decodes one huffman symbol from the
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* bitstream using the stated table and puts it in var.
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*/
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#define READ_HUFFSYM(tbl,var) do { \
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ENSURE_BITS(16); \
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hufftbl = SYMTABLE(tbl); \
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if ((i = hufftbl[PEEK_BITS(TABLEBITS(tbl))]) >= MAXSYMBOLS(tbl)) { \
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j = 1 << (ULONG_BITS - TABLEBITS(tbl)); \
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do { \
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j >>= 1; i <<= 1; i |= (bitbuf & j) ? 1 : 0; \
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if (!j) { return DECR_ILLEGALDATA; } \
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} while ((i = hufftbl[i]) >= MAXSYMBOLS(tbl)); \
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} \
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j = LENTABLE(tbl)[(var) = i]; \
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REMOVE_BITS(j); \
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} while (0)
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/* READ_LENGTHS(tablename, first, last) reads in code lengths for symbols
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* first to last in the given table. The code lengths are stored in their
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* own special LZX way.
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*/
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#define READ_LENGTHS(tbl,first,last) do { \
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lb.bb = bitbuf; lb.bl = bitsleft; lb.ip = inpos; \
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if (lzx_read_lens(pState, LENTABLE(tbl),(first),(last),&lb)) { \
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return DECR_ILLEGALDATA; \
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} \
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bitbuf = lb.bb; bitsleft = lb.bl; inpos = lb.ip; \
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} while (0)
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/* make_decode_table(nsyms, nbits, length[], table[])
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*
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* This function was coded by David Tritscher. It builds a fast huffman
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* decoding table out of just a canonical huffman code lengths table.
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*
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* nsyms = total number of symbols in this huffman tree.
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* nbits = any symbols with a code length of nbits or less can be decoded
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* in one lookup of the table.
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* length = A table to get code lengths from [0 to syms-1]
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* table = The table to fill up with decoded symbols and pointers.
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*
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* Returns 0 for OK or 1 for error
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*/
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static int make_decode_table(ULONG nsyms, ULONG nbits, UBYTE *length, UWORD *table) {
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register UWORD sym;
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register ULONG leaf;
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register UBYTE bit_num = 1;
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ULONG fill;
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ULONG pos = 0; /* the current position in the decode table */
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ULONG table_mask = 1 << nbits;
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ULONG bit_mask = table_mask >> 1; /* don't do 0 length codes */
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ULONG next_symbol = bit_mask; /* base of allocation for long codes */
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/* fill entries for codes short enough for a direct mapping */
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while (bit_num <= nbits) {
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for (sym = 0; sym < nsyms; sym++) {
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if (length[sym] == bit_num) {
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leaf = pos;
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if((pos += bit_mask) > table_mask) return 1; /* table overrun */
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/* fill all possible lookups of this symbol with the symbol itself */
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fill = bit_mask;
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while (fill-- > 0) table[leaf++] = sym;
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}
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}
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bit_mask >>= 1;
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bit_num++;
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}
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/* if there are any codes longer than nbits */
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if (pos != table_mask) {
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/* clear the remainder of the table */
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for (sym = pos; sym < table_mask; sym++) table[sym] = 0;
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/* give ourselves room for codes to grow by up to 16 more bits */
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pos <<= 16;
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table_mask <<= 16;
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bit_mask = 1 << 15;
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while (bit_num <= 16) {
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for (sym = 0; sym < nsyms; sym++) {
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if (length[sym] == bit_num) {
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leaf = pos >> 16;
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for (fill = 0; fill < bit_num - nbits; fill++) {
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/* if this path hasn't been taken yet, 'allocate' two entries */
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if (table[leaf] == 0) {
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table[(next_symbol << 1)] = 0;
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table[(next_symbol << 1) + 1] = 0;
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table[leaf] = next_symbol++;
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}
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/* follow the path and select either left or right for next bit */
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leaf = table[leaf] << 1;
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if ((pos >> (15-fill)) & 1) leaf++;
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}
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table[leaf] = sym;
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if ((pos += bit_mask) > table_mask) return 1; /* table overflow */
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}
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}
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bit_mask >>= 1;
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bit_num++;
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}
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}
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/* full table? */
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if (pos == table_mask) return 0;
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/* either erroneous table, or all elements are 0 - let's find out. */
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for (sym = 0; sym < nsyms; sym++) if (length[sym]) return 1;
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return 0;
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}
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struct lzx_bits {
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ULONG bb;
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int bl;
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UBYTE *ip;
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};
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static int lzx_read_lens(struct LZXstate *pState, UBYTE *lens, ULONG first, ULONG last, struct lzx_bits *lb) {
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ULONG i,j, x,y;
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int z;
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register ULONG bitbuf = lb->bb;
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register int bitsleft = lb->bl;
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UBYTE *inpos = lb->ip;
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UWORD *hufftbl;
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for (x = 0; x < 20; x++) {
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READ_BITS(y, 4);
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LENTABLE(PRETREE)[x] = y;
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}
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BUILD_TABLE(PRETREE);
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for (x = first; x < last; ) {
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READ_HUFFSYM(PRETREE, z);
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if (z == 17) {
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READ_BITS(y, 4); y += 4;
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while (y--) lens[x++] = 0;
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}
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else if (z == 18) {
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READ_BITS(y, 5); y += 20;
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while (y--) lens[x++] = 0;
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|
}
|
|
else if (z == 19) {
|
|
READ_BITS(y, 1); y += 4;
|
|
READ_HUFFSYM(PRETREE, z);
|
|
z = lens[x] - z; if (z < 0) z += 17;
|
|
while (y--) lens[x++] = z;
|
|
}
|
|
else {
|
|
z = lens[x] - z; if (z < 0) z += 17;
|
|
lens[x++] = z;
|
|
}
|
|
}
|
|
|
|
lb->bb = bitbuf;
|
|
lb->bl = bitsleft;
|
|
lb->ip = inpos;
|
|
return 0;
|
|
}
|
|
|
|
int LZXdecompress(struct LZXstate *pState, unsigned char *inpos, unsigned char *outpos, int inlen, int outlen) {
|
|
UBYTE *endinp = inpos + inlen;
|
|
UBYTE *window = pState->window;
|
|
UBYTE *runsrc, *rundest;
|
|
UWORD *hufftbl; /* used in READ_HUFFSYM macro as chosen decoding table */
|
|
|
|
ULONG window_posn = pState->window_posn;
|
|
ULONG window_size = pState->window_size;
|
|
ULONG R0 = pState->R0;
|
|
ULONG R1 = pState->R1;
|
|
ULONG R2 = pState->R2;
|
|
|
|
register ULONG bitbuf;
|
|
register int bitsleft;
|
|
ULONG match_offset, i,j,k; /* ijk used in READ_HUFFSYM macro */
|
|
struct lzx_bits lb; /* used in READ_LENGTHS macro */
|
|
|
|
int togo = outlen, this_run, main_element, aligned_bits;
|
|
int match_length, length_footer, extra, verbatim_bits;
|
|
int copy_length;
|
|
|
|
INIT_BITSTREAM;
|
|
|
|
/* read header if necessary */
|
|
if (!pState->header_read) {
|
|
i = j = 0;
|
|
READ_BITS(k, 1); if (k) { READ_BITS(i,16); READ_BITS(j,16); }
|
|
pState->intel_filesize = (i << 16) | j; /* or 0 if not encoded */
|
|
pState->header_read = 1;
|
|
}
|
|
|
|
/* main decoding loop */
|
|
while (togo > 0) {
|
|
/* last block finished, new block expected */
|
|
if (pState->block_remaining == 0) {
|
|
if (pState->block_type == LZX_BLOCKTYPE_UNCOMPRESSED) {
|
|
if (pState->block_length & 1) inpos++; /* realign bitstream to word */
|
|
INIT_BITSTREAM;
|
|
}
|
|
|
|
READ_BITS(pState->block_type, 3);
|
|
READ_BITS(i, 16);
|
|
READ_BITS(j, 8);
|
|
pState->block_remaining = pState->block_length = (i << 8) | j;
|
|
|
|
switch (pState->block_type) {
|
|
case LZX_BLOCKTYPE_ALIGNED:
|
|
for (i = 0; i < 8; i++) { READ_BITS(j, 3); LENTABLE(ALIGNED)[i] = j; }
|
|
BUILD_TABLE(ALIGNED);
|
|
/* rest of aligned header is same as verbatim */
|
|
|
|
case LZX_BLOCKTYPE_VERBATIM:
|
|
READ_LENGTHS(MAINTREE, 0, 256);
|
|
READ_LENGTHS(MAINTREE, 256, pState->main_elements);
|
|
BUILD_TABLE(MAINTREE);
|
|
if (LENTABLE(MAINTREE)[0xE8] != 0) pState->intel_started = 1;
|
|
|
|
READ_LENGTHS(LENGTH, 0, LZX_NUM_SECONDARY_LENGTHS);
|
|
BUILD_TABLE(LENGTH);
|
|
break;
|
|
|
|
case LZX_BLOCKTYPE_UNCOMPRESSED:
|
|
pState->intel_started = 1; /* because we can't assume otherwise */
|
|
ENSURE_BITS(16); /* get up to 16 pad bits into the buffer */
|
|
if (bitsleft > 16) inpos -= 2; /* and align the bitstream! */
|
|
R0 = inpos[0]|(inpos[1]<<8)|(inpos[2]<<16)|(inpos[3]<<24);inpos+=4;
|
|
R1 = inpos[0]|(inpos[1]<<8)|(inpos[2]<<16)|(inpos[3]<<24);inpos+=4;
|
|
R2 = inpos[0]|(inpos[1]<<8)|(inpos[2]<<16)|(inpos[3]<<24);inpos+=4;
|
|
break;
|
|
|
|
default:
|
|
return DECR_ILLEGALDATA;
|
|
}
|
|
}
|
|
|
|
/* buffer exhaustion check */
|
|
if (inpos > endinp) {
|
|
/* it's possible to have a file where the next run is less than
|
|
* 16 bits in size. In this case, the READ_HUFFSYM() macro used
|
|
* in building the tables will exhaust the buffer, so we should
|
|
* allow for this, but not allow those accidentally read bits to
|
|
* be used (so we check that there are at least 16 bits
|
|
* remaining - in this boundary case they aren't really part of
|
|
* the compressed data)
|
|
*/
|
|
if (inpos > (endinp+2) || bitsleft < 16) return DECR_ILLEGALDATA;
|
|
}
|
|
|
|
while ((this_run = pState->block_remaining) > 0 && togo > 0) {
|
|
if (this_run > togo) this_run = togo;
|
|
togo -= this_run;
|
|
pState->block_remaining -= this_run;
|
|
|
|
/* apply 2^x-1 mask */
|
|
window_posn &= window_size - 1;
|
|
/* runs can't straddle the window wraparound */
|
|
if ((window_posn + this_run) > window_size)
|
|
return DECR_DATAFORMAT;
|
|
|
|
switch (pState->block_type) {
|
|
|
|
case LZX_BLOCKTYPE_VERBATIM:
|
|
while (this_run > 0) {
|
|
READ_HUFFSYM(MAINTREE, main_element);
|
|
|
|
if (main_element < LZX_NUM_CHARS) {
|
|
/* literal: 0 to LZX_NUM_CHARS-1 */
|
|
window[window_posn++] = main_element;
|
|
this_run--;
|
|
}
|
|
else {
|
|
/* match: LZX_NUM_CHARS + ((slot<<3) | length_header (3 bits)) */
|
|
main_element -= LZX_NUM_CHARS;
|
|
|
|
match_length = main_element & LZX_NUM_PRIMARY_LENGTHS;
|
|
if (match_length == LZX_NUM_PRIMARY_LENGTHS) {
|
|
READ_HUFFSYM(LENGTH, length_footer);
|
|
match_length += length_footer;
|
|
}
|
|
match_length += LZX_MIN_MATCH;
|
|
|
|
match_offset = main_element >> 3;
|
|
|
|
if (match_offset > 2) {
|
|
/* not repeated offset */
|
|
if (match_offset != 3) {
|
|
extra = extra_bits[match_offset];
|
|
READ_BITS(verbatim_bits, extra);
|
|
match_offset = position_base[match_offset] - 2 + verbatim_bits;
|
|
}
|
|
else {
|
|
match_offset = 1;
|
|
}
|
|
|
|
/* update repeated offset LRU queue */
|
|
R2 = R1; R1 = R0; R0 = match_offset;
|
|
}
|
|
else if (match_offset == 0) {
|
|
match_offset = R0;
|
|
}
|
|
else if (match_offset == 1) {
|
|
match_offset = R1;
|
|
R1 = R0; R0 = match_offset;
|
|
}
|
|
else /* match_offset == 2 */ {
|
|
match_offset = R2;
|
|
R2 = R0; R0 = match_offset;
|
|
}
|
|
|
|
rundest = window + window_posn;
|
|
this_run -= match_length;
|
|
|
|
/* copy any wrapped around source data */
|
|
if (window_posn >= match_offset) {
|
|
/* no wrap */
|
|
runsrc = rundest - match_offset;
|
|
} else {
|
|
runsrc = rundest + (window_size - match_offset);
|
|
copy_length = match_offset - window_posn;
|
|
if (copy_length < match_length) {
|
|
match_length -= copy_length;
|
|
window_posn += copy_length;
|
|
while (copy_length-- > 0) *rundest++ = *runsrc++;
|
|
runsrc = window;
|
|
}
|
|
}
|
|
window_posn += match_length;
|
|
|
|
/* copy match data - no worries about destination wraps */
|
|
while (match_length-- > 0) *rundest++ = *runsrc++;
|
|
|
|
}
|
|
}
|
|
break;
|
|
|
|
case LZX_BLOCKTYPE_ALIGNED:
|
|
while (this_run > 0) {
|
|
READ_HUFFSYM(MAINTREE, main_element);
|
|
|
|
if (main_element < LZX_NUM_CHARS) {
|
|
/* literal: 0 to LZX_NUM_CHARS-1 */
|
|
window[window_posn++] = main_element;
|
|
this_run--;
|
|
}
|
|
else {
|
|
/* match: LZX_NUM_CHARS + ((slot<<3) | length_header (3 bits)) */
|
|
main_element -= LZX_NUM_CHARS;
|
|
|
|
match_length = main_element & LZX_NUM_PRIMARY_LENGTHS;
|
|
if (match_length == LZX_NUM_PRIMARY_LENGTHS) {
|
|
READ_HUFFSYM(LENGTH, length_footer);
|
|
match_length += length_footer;
|
|
}
|
|
match_length += LZX_MIN_MATCH;
|
|
|
|
match_offset = main_element >> 3;
|
|
|
|
if (match_offset > 2) {
|
|
/* not repeated offset */
|
|
extra = extra_bits[match_offset];
|
|
match_offset = position_base[match_offset] - 2;
|
|
if (extra > 3) {
|
|
/* verbatim and aligned bits */
|
|
extra -= 3;
|
|
READ_BITS(verbatim_bits, extra);
|
|
match_offset += (verbatim_bits << 3);
|
|
READ_HUFFSYM(ALIGNED, aligned_bits);
|
|
match_offset += aligned_bits;
|
|
}
|
|
else if (extra == 3) {
|
|
/* aligned bits only */
|
|
READ_HUFFSYM(ALIGNED, aligned_bits);
|
|
match_offset += aligned_bits;
|
|
}
|
|
else if (extra > 0) { /* extra==1, extra==2 */
|
|
/* verbatim bits only */
|
|
READ_BITS(verbatim_bits, extra);
|
|
match_offset += verbatim_bits;
|
|
}
|
|
else /* extra == 0 */ {
|
|
/* ??? */
|
|
match_offset = 1;
|
|
}
|
|
|
|
/* update repeated offset LRU queue */
|
|
R2 = R1; R1 = R0; R0 = match_offset;
|
|
}
|
|
else if (match_offset == 0) {
|
|
match_offset = R0;
|
|
}
|
|
else if (match_offset == 1) {
|
|
match_offset = R1;
|
|
R1 = R0; R0 = match_offset;
|
|
}
|
|
else /* match_offset == 2 */ {
|
|
match_offset = R2;
|
|
R2 = R0; R0 = match_offset;
|
|
}
|
|
|
|
rundest = window + window_posn;
|
|
this_run -= match_length;
|
|
|
|
/* copy any wrapped around source data */
|
|
if (window_posn >= match_offset) {
|
|
/* no wrap */
|
|
runsrc = rundest - match_offset;
|
|
} else {
|
|
runsrc = rundest + (window_size - match_offset);
|
|
copy_length = match_offset - window_posn;
|
|
if (copy_length < match_length) {
|
|
match_length -= copy_length;
|
|
window_posn += copy_length;
|
|
while (copy_length-- > 0) *rundest++ = *runsrc++;
|
|
runsrc = window;
|
|
}
|
|
}
|
|
window_posn += match_length;
|
|
|
|
/* copy match data - no worries about destination wraps */
|
|
while (match_length-- > 0) *rundest++ = *runsrc++;
|
|
|
|
}
|
|
}
|
|
break;
|
|
|
|
case LZX_BLOCKTYPE_UNCOMPRESSED:
|
|
if ((inpos + this_run) > endinp) return DECR_ILLEGALDATA;
|
|
memcpy(window + window_posn, inpos, (size_t) this_run);
|
|
inpos += this_run; window_posn += this_run;
|
|
break;
|
|
|
|
default:
|
|
return DECR_ILLEGALDATA; /* might as well */
|
|
}
|
|
|
|
}
|
|
}
|
|
|
|
if (togo != 0) return DECR_ILLEGALDATA;
|
|
memcpy(outpos, window + ((!window_posn) ? window_size : window_posn) - outlen, (size_t) outlen);
|
|
|
|
pState->window_posn = window_posn;
|
|
pState->R0 = R0;
|
|
pState->R1 = R1;
|
|
pState->R2 = R2;
|
|
|
|
/* intel E8 decoding */
|
|
if ((pState->frames_read++ < 32768) && pState->intel_filesize != 0) {
|
|
if (outlen <= 6 || !pState->intel_started) {
|
|
pState->intel_curpos += outlen;
|
|
}
|
|
else {
|
|
UBYTE *data = outpos;
|
|
UBYTE *dataend = data + outlen - 10;
|
|
LONG curpos = pState->intel_curpos;
|
|
LONG filesize = pState->intel_filesize;
|
|
LONG abs_off, rel_off;
|
|
|
|
pState->intel_curpos = curpos + outlen;
|
|
|
|
while (data < dataend) {
|
|
if (*data++ != 0xE8) { curpos++; continue; }
|
|
abs_off = data[0] | (data[1]<<8) | (data[2]<<16) | (data[3]<<24);
|
|
if ((abs_off >= -curpos) && (abs_off < filesize)) {
|
|
rel_off = (abs_off >= 0) ? abs_off - curpos : abs_off + filesize;
|
|
data[0] = (UBYTE) rel_off;
|
|
data[1] = (UBYTE) (rel_off >> 8);
|
|
data[2] = (UBYTE) (rel_off >> 16);
|
|
data[3] = (UBYTE) (rel_off >> 24);
|
|
}
|
|
data += 4;
|
|
curpos += 5;
|
|
}
|
|
}
|
|
}
|
|
return DECR_OK;
|
|
}
|
|
|
|
#ifdef LZX_CHM_TESTDRIVER
|
|
int main(int c, char **v)
|
|
{
|
|
FILE *fin, *fout;
|
|
struct LZXstate state;
|
|
UBYTE ibuf[16384];
|
|
UBYTE obuf[32768];
|
|
int ilen, olen;
|
|
int status;
|
|
int i;
|
|
int count=0;
|
|
int w = atoi(v[1]);
|
|
LZXinit(&state, w);
|
|
fout = fopen(v[2], "wb");
|
|
for (i=3; i<c; i++)
|
|
{
|
|
fin = fopen(v[i], "rb");
|
|
ilen = fread(ibuf, 1, 16384, fin);
|
|
status = LZXdecompress(&state, ibuf, obuf, ilen, 32768);
|
|
switch (status)
|
|
{
|
|
case DECR_OK:
|
|
printf("ok\n");
|
|
fwrite(obuf, 1, 32768, fout);
|
|
break;
|
|
case DECR_DATAFORMAT:
|
|
printf("bad format\n");
|
|
break;
|
|
case DECR_ILLEGALDATA:
|
|
printf("illegal data\n");
|
|
break;
|
|
case DECR_NOMEMORY:
|
|
printf("no memory\n");
|
|
break;
|
|
default:
|
|
break;
|
|
}
|
|
fclose(fin);
|
|
if (++count == 2)
|
|
{
|
|
count = 0;
|
|
LZXreset(&state);
|
|
}
|
|
}
|
|
fclose(fout);
|
|
}
|
|
#endif
|