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