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797 lines
24 KiB
797 lines
24 KiB
/* Most of this file is taken from:
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cabextract 0.5 - a program to extract Microsoft Cabinet files
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(C) 2000-2001 Stuart Caie <kyzer@4u.net>
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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 Library General Public
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License as published by the Free Software Foundation; either
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version 2 of the License, or (at your option) any later version.
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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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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public License
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along with this library; see the file COPYING.LIB. If not, write to
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the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
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Boston, MA 02110-1301, USA.
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include "decompress.h"
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int make_decode_table(ULONG nsyms, ULONG nbits, UBYTE *length, UWORD *table);
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int lzx_read_lens(UBYTE *lens, ULONG first, ULONG last, lzx_bits *lb);
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/*--------------------------------------------------------------------------*/
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/* our archiver information / state */
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/* LZX stuff */
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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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/* generic stuff */
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#define CAB(x) (decomp_state.x)
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#define LZX(x) (decomp_state.lzx.x)
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#define DECR_OK (0)
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#define DECR_DATAFORMAT (1)
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#define DECR_ILLEGALDATA (2)
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#define DECR_NOMEMORY (3)
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#define DECR_CHECKSUM (4)
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#define DECR_INPUT (5)
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#define DECR_OUTPUT (6)
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struct
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{
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struct LZXstate lzx;
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} decomp_state;
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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 ULONG position_base[51];
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static UBYTE extra_bits[51];
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int LZXinit(int window) {
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ULONG wndsize = 1 << window;
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int i, j, 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 DECR_DATAFORMAT;
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if (LZX(actual_size) < wndsize)
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{
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if (LZX(window)) free(LZX(window));
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LZX(window) = NULL;
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}
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if (!LZX(window))
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{
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if (!(LZX(window) = (UBYTE*)malloc(wndsize))) return DECR_NOMEMORY;
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LZX(actual_size) = wndsize;
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}
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LZX(window_size) = wndsize;
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/* initialise static tables */
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for (i=0, j=0; i <= 49; i += 2)
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{
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extra_bits[i] = extra_bits[i+1] = j; /* 0,0,0,0,1,1,2,2,3,3... */
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if ((i != 0) && (j < 17)) j++; /* 0,0,1,2,3,4...15,16,17,17,17,17... */
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}
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for (i=0, j=0; i <= 50; i++)
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{
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position_base[i] = j; /* 0,1,2,3,4,6,8,12,16,24,32,... */
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j += 1 << extra_bits[i]; /* 1,1,1,1,2,2,4,4,8,8,16,16,32,32,... */
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}
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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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/*posn_slots=i=0; while (i < wndsize) i += 1 << extra_bits[posn_slots++]; */
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LZX(R0) = LZX(R1) = LZX(R2) = 1;
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LZX(main_elements) = LZX_NUM_CHARS + (posn_slots << 3);
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LZX(header_read) = 0;
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LZX(frames_read) = 0;
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LZX(block_remaining) = 0;
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LZX(block_type) = LZX_BLOCKTYPE_INVALID;
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LZX(intel_curpos) = 0;
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LZX(intel_started) = 0;
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LZX(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++) LZX(MAINTREE_len)[i] = 0;
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for (i = 0; i < LZX_LENGTH_MAXSYMBOLS; i++) LZX(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) (LZX(tbl##_table))
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#define LENTABLE(tbl) (LZX(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(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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int make_decode_table(ULONG nsyms, ULONG nbits, UBYTE *length, UWORD *table) {
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UWORD sym;
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ULONG leaf;
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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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{
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for (sym = 0; sym < nsyms; sym++)
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{
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if (length[sym] == bit_num)
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{
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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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{
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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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{
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for (sym = 0; sym < nsyms; sym++)
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{
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if (length[sym] == bit_num)
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{
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leaf = pos >> 16;
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for (fill = 0; fill < bit_num - nbits; fill++)
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{
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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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{
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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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int lzx_read_lens(UBYTE *lens, ULONG first, ULONG last, lzx_bits *lb) {
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ULONG i,j, x,y;
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int z;
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ULONG bitbuf = lb->bb;
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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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{
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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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{
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READ_HUFFSYM(PRETREE, z);
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if (z == 17)
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{
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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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{
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READ_BITS(y, 5); y += 20;
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while (y--) lens[x++] = 0;
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}
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else if (z == 19)
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{
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READ_BITS(y, 1); y += 4;
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READ_HUFFSYM(PRETREE, z);
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z = lens[x] - z; if (z < 0) z += 17;
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while (y--) lens[x++] = z;
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}
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else
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{
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z = lens[x] - z; if (z < 0) z += 17;
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lens[x++] = z;
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}
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}
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lb->bb = bitbuf;
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lb->bl = bitsleft;
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lb->ip = inpos;
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return 0;
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}
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int LZXdecompress(UBYTE* inpos, int inlen, UBYTE* outpos, int outlen) {
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UBYTE *endinp = inpos + inlen;
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UBYTE *window = LZX(window);
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UBYTE *runsrc, *rundest;
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UWORD *hufftbl; /* used in READ_HUFFSYM macro as chosen decoding table */
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ULONG window_posn = LZX(window_posn);
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ULONG window_size = LZX(window_size);
|
|
ULONG R0 = LZX(R0);
|
|
ULONG R1 = LZX(R1);
|
|
ULONG R2 = LZX(R2);
|
|
|
|
ULONG bitbuf;
|
|
int bitsleft;
|
|
ULONG match_offset, i,j,k; /* ijk used in READ_HUFFSYM macro */
|
|
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;
|
|
|
|
INIT_BITSTREAM;
|
|
|
|
/* read header if necessary */
|
|
if (!LZX(header_read))
|
|
{
|
|
i = j = 0;
|
|
READ_BITS(k, 1); if (k)
|
|
{
|
|
READ_BITS(i,16); READ_BITS(j,16);
|
|
}
|
|
LZX(intel_filesize) = (i << 16) | j; /* or 0 if not encoded */
|
|
LZX(header_read) = 1;
|
|
}
|
|
|
|
/* main decoding loop */
|
|
while (togo > 0)
|
|
{
|
|
/* last block finished, new block expected */
|
|
if (LZX(block_remaining) == 0)
|
|
{
|
|
if (LZX(block_type) == LZX_BLOCKTYPE_UNCOMPRESSED)
|
|
{
|
|
if (LZX(block_length) & 1) inpos++; /* realign bitstream to word */
|
|
INIT_BITSTREAM;
|
|
}
|
|
|
|
READ_BITS(LZX(block_type), 3);
|
|
READ_BITS(i, 16);
|
|
READ_BITS(j, 8);
|
|
LZX(block_remaining) = LZX(block_length) = (i << 8) | j;
|
|
|
|
switch (LZX(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, LZX(main_elements));
|
|
BUILD_TABLE(MAINTREE);
|
|
if (LENTABLE(MAINTREE)[0xE8] != 0) LZX(intel_started) = 1;
|
|
|
|
READ_LENGTHS(LENGTH, 0, LZX_NUM_SECONDARY_LENGTHS);
|
|
BUILD_TABLE(LENGTH);
|
|
break;
|
|
|
|
case LZX_BLOCKTYPE_UNCOMPRESSED:
|
|
LZX(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 = LZX(block_remaining)) > 0 && togo > 0)
|
|
{
|
|
if (this_run > togo) this_run = togo;
|
|
togo -= this_run;
|
|
LZX(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 (LZX(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;
|
|
runsrc = rundest - match_offset;
|
|
window_posn += match_length;
|
|
this_run -= match_length;
|
|
|
|
/* copy any wrapped around source data */
|
|
while ((runsrc < window) && (match_length-- > 0))
|
|
{
|
|
*rundest++ = *(runsrc + window_size); runsrc++;
|
|
}
|
|
/* 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;
|
|
runsrc = rundest - match_offset;
|
|
window_posn += match_length;
|
|
this_run -= match_length;
|
|
|
|
/* copy any wrapped around source data */
|
|
while ((runsrc < window) && (match_length-- > 0))
|
|
{
|
|
*rundest++ = *(runsrc + window_size); runsrc++;
|
|
}
|
|
/* 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);
|
|
|
|
LZX(window_posn) = window_posn;
|
|
LZX(R0) = R0;
|
|
LZX(R1) = R1;
|
|
LZX(R2) = R2;
|
|
|
|
/* intel E8 decoding */
|
|
if ((LZX(frames_read)++ < 32768) && LZX(intel_filesize) != 0)
|
|
{
|
|
if (outlen <= 6 || !LZX(intel_started))
|
|
{
|
|
LZX(intel_curpos) += outlen;
|
|
}
|
|
else
|
|
{
|
|
UBYTE *data = outpos;
|
|
UBYTE *dataend = data + outlen - 10;
|
|
LONG curpos = LZX(intel_curpos);
|
|
LONG filesize = LZX(intel_filesize);
|
|
LONG abs_off, rel_off;
|
|
|
|
LZX(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;
|
|
}
|
|
|