libclamav/mspack.c
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 /*
  * This file includes code from libmspack adapted for libclamav by
  * tkojm@clamav.net
  *
  * Copyright (C) 2003-2004 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 version 2.1 as published by the Free Software Foundation.
  *
  * 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 Street, Fifth Floor, Boston, MA 02110-1301
  * USA
  */
 
 #if HAVE_CONFIG_H
 #include "clamav-config.h"
 #endif
 
 #include <stdio.h>
 #include <string.h>
 
 #include "others.h"
 #include "clamav.h"
 #include "mspack.h"
 
 #if HAVE_LIMITS_H
 # include <limits.h>
 #endif
 #ifndef CHAR_BIT
 # define CHAR_BIT (8)
 #endif
 
 
 /***************************************************************************
  *			 MS-ZIP decompression implementation 
  ***************************************************************************
  * The LZX method was created by Jonathan Forbes and Tomi Poutanen, adapted
  * by Microsoft Corporation.
  *
  * The deflate method was created by Phil Katz. MSZIP is equivalent to the
  * deflate method.
  *
  */
 
 /* match lengths for literal codes 257.. 285 */
 static const unsigned short mszip_lit_lengths[29] = {
   3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 15, 17, 19, 23, 27,
   31, 35, 43, 51, 59, 67, 83, 99, 115, 131, 163, 195, 227, 258
 };
 
 /* match offsets for distance codes 0 .. 29 */
 static const unsigned short mszip_dist_offsets[30] = {
   1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193, 257, 385,
   513, 769, 1025, 1537, 2049, 3073, 4097, 6145, 8193, 12289, 16385, 24577
 };
 
 /* extra bits required for literal codes 257.. 285 */
 static const unsigned char mszip_lit_extrabits[29] = {
   0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2,
   2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 0
 };
 
 /* extra bits required for distance codes 0 .. 29 */
 static const unsigned char mszip_dist_extrabits[30] = {
   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
 };
 
 /* the order of the bit length Huffman code lengths */
 static const unsigned char mszip_bitlen_order[19] = {
   16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15
 };
 
 /* ANDing with mszip_bit_mask[n] masks the lower n bits */
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 static const unsigned short mszip_bit_mask_tab[17] = {
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  0x0000, 0x0001, 0x0003, 0x0007, 0x000f, 0x001f, 0x003f, 0x007f, 0x00ff,
  0x01ff, 0x03ff, 0x07ff, 0x0fff, 0x1fff, 0x3fff, 0x7fff, 0xffff
 };
 
 #define MSZIP_STORE_BITS do {                                                 \
   zip->i_ptr      = i_ptr;                                              \
   zip->i_end      = i_end;                                              \
   zip->bit_buffer = bit_buffer;                                         \
   zip->bits_left  = bits_left;                                          \
 } while (0)
 
 #define MSZIP_RESTORE_BITS do {                                               \
   i_ptr      = zip->i_ptr;                                              \
   i_end      = zip->i_end;                                              \
   bit_buffer = zip->bit_buffer;                                         \
   bits_left  = zip->bits_left;                                          \
 } while (0)
 
 #define MSZIP_ENSURE_BITS(nbits) do {                                         \
   while (bits_left < (nbits)) {                                         \
     if (i_ptr >= i_end) {                                               \
       if (mszip_read_input(zip)) return zip->error;                      \
       i_ptr = zip->i_ptr;                                               \
       i_end = zip->i_end;                                               \
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       if(i_ptr == i_end) break;						\
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     }                                                                   \
     bit_buffer |= *i_ptr++ << bits_left; bits_left  += 8;               \
   }                                                                     \
 } while (0)
 
 #define MSZIP_PEEK_BITS(nbits)   (bit_buffer & ((1<<(nbits))-1))
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 #define MSZIP_PEEK_BITS_T(nbits) (bit_buffer & mszip_bit_mask_tab[(nbits)])
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 #define MSZIP_REMOVE_BITS(nbits) ((bit_buffer >>= (nbits)), (bits_left -= (nbits)))
 
 #define MSZIP_READ_BITS(val, nbits) do {                                      \
   MSZIP_ENSURE_BITS(nbits); (val) = MSZIP_PEEK_BITS(nbits); MSZIP_REMOVE_BITS(nbits);     \
 } while (0)
 
 #define MSZIP_READ_BITS_T(val, nbits) do {                                    \
   MSZIP_ENSURE_BITS(nbits); (val) = MSZIP_PEEK_BITS_T(nbits); MSZIP_REMOVE_BITS(nbits);   \
 } while (0)
 
 static int mszip_read_input(struct mszip_stream *zip) {
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   int nread = zip->read_cb ? zip->read_cb(zip->file, zip->inbuf, (int)zip->inbuf_size) : cli_readn(zip->fd, zip->inbuf, (int)zip->inbuf_size);
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   if (nread < 0) {
     if (zip->file->error == CL_BREAK)
       return zip->error = CL_BREAK;
     else
       return zip->error = CL_EFORMAT;
   }
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   zip->i_ptr = &zip->inbuf[0];
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   zip->i_end = &zip->inbuf[nread];
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   return CL_SUCCESS;
 }
 
 /* inflate() error codes */
 #define INF_ERR_BLOCKTYPE   (-1)  /* unknown block type                      */
 #define INF_ERR_COMPLEMENT  (-2)  /* block size complement mismatch          */
 #define INF_ERR_FLUSH       (-3)  /* error from flush_window() callback      */
 #define INF_ERR_BITBUF      (-4)  /* too many bits in bit buffer             */
 #define INF_ERR_SYMLENS     (-5)  /* too many symbols in blocktype 2 header  */
 #define INF_ERR_BITLENTBL   (-6)  /* failed to build bitlens huffman table   */
 #define INF_ERR_LITERALTBL  (-7)  /* failed to build literals huffman table  */
 #define INF_ERR_DISTANCETBL (-8)  /* failed to build distance huffman table  */
 #define INF_ERR_BITOVERRUN  (-9)  /* bitlen RLE code goes over table size    */
 #define INF_ERR_BADBITLEN   (-10) /* invalid bit-length code                 */
 #define INF_ERR_LITCODE     (-11) /* out-of-range literal code               */
 #define INF_ERR_DISTCODE    (-12) /* out-of-range distance code              */
 #define INF_ERR_DISTANCE    (-13) /* somehow, distance is beyond 32k         */
 #define INF_ERR_HUFFSYM     (-14) /* out of bits decoding huffman symbol     */
 
 /* mszip_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.
  *
  * NOTE: this is NOT identical to the mszip_make_decode_table() in lzxd.c. This
  * one reverses the quick-lookup bit pattern. Bits are read MSB to LSB in LZX,
  * but LSB to MSB in MSZIP.
  *
  * 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 nsyms-1]
  * table  = The table to fill up with decoded symbols and pointers.
  *
  * Returns 0 for OK or 1 for error
  */
 static int mszip_make_decode_table(unsigned int nsyms, unsigned int nbits,
 			     unsigned char *length, unsigned short *table)
 {
   register unsigned int leaf, reverse, fill;
   register unsigned short sym, next_sym;
   register unsigned char bit_num;
   unsigned int pos         = 0; /* the current position in the decode table */
   unsigned int table_mask  = 1 << nbits;
   unsigned int mszip_bit_mask    = table_mask >> 1; /* don't do 0 length codes */
 
   /* fill entries for codes short enough for a direct mapping */
   for (bit_num = 1; bit_num <= nbits; bit_num++) {
     for (sym = 0; sym < nsyms; sym++) {
       if (length[sym] != bit_num) continue;
 
       /* reverse the significant bits */
       fill = length[sym]; reverse = pos >> (nbits - fill); leaf = 0;
       do {leaf <<= 1; leaf |= reverse & 1; reverse >>= 1;} while (--fill);
 
       if((pos += mszip_bit_mask) > table_mask) return 1; /* table overrun */
 
       /* fill all possible lookups of this symbol with the symbol itself */
       fill = mszip_bit_mask; next_sym = 1 << bit_num;
       do { table[leaf] = sym; leaf += next_sym; } while (--fill);
     }
     mszip_bit_mask >>= 1;
   }
 
   /* exit with success if table is now complete */
   if (pos == table_mask) return 0;
 
   /* mark all remaining table entries as unused */
   for (sym = pos; sym < table_mask; sym++) {
     reverse = sym; leaf = 0; fill = nbits;
     do { leaf <<= 1; leaf |= reverse & 1; reverse >>= 1; } while (--fill);
     table[leaf] = 0xFFFF;
   }
 
   /* where should the longer codes be allocated from? */
   next_sym = ((table_mask >> 1) < nsyms) ? nsyms : (table_mask >> 1);
 
   /* give ourselves room for codes to grow by up to 16 more bits.
    * codes now start at bit nbits+16 and end at (nbits+16-codelength) */
   pos <<= 16;
   table_mask <<= 16;
   mszip_bit_mask = 1 << 15;
 
   for (bit_num = nbits+1; bit_num <= MSZIP_MAX_HUFFBITS; bit_num++) {
     for (sym = 0; sym < nsyms; sym++) {
       if (length[sym] != bit_num) continue;
 
       /* leaf = the first nbits of the code, reversed */
       reverse = pos >> 16; leaf = 0; fill = nbits;
       do {leaf <<= 1; leaf |= reverse & 1; reverse >>= 1;} while (--fill);
 
       for (fill = 0; fill < (bit_num - nbits); fill++) {
 	/* if this path hasn't been taken yet, 'allocate' two entries */
 	if (table[leaf] == 0xFFFF) {
 	  table[(next_sym << 1)     ] = 0xFFFF;
 	  table[(next_sym << 1) + 1 ] = 0xFFFF;
 	  table[leaf] = next_sym++;
 	}
 	/* follow the path and select either left or right for next bit */
 	leaf = (table[leaf] << 1) | ((pos >> (15 - fill)) & 1);
       }
       table[leaf] = sym;
 
       if ((pos += mszip_bit_mask) > table_mask) return 1; /* table overflow */
     }
     mszip_bit_mask >>= 1;
   }
 
   /* full table? */
   return (pos != table_mask) ? 1 : 0;
 }
 
 /* MSZIP_READ_HUFFSYM(tablename, var) decodes one huffman symbol from the
  * bitstream using the stated table and puts it in var.
  */
 #define MSZIP_READ_HUFFSYM(tbl, var) do {                                     \
   /* huffman symbols can be up to 16 bits long */                       \
   MSZIP_ENSURE_BITS(MSZIP_MAX_HUFFBITS);                                      \
   /* immediate table lookup of [tablebits] bits of the code */          \
   sym = zip->tbl##_table[MSZIP_PEEK_BITS(MSZIP_##tbl##_TABLEBITS)];		\
   /* is the symbol is longer than [tablebits] bits? (i=node index) */   \
   if (sym >= MSZIP_##tbl##_MAXSYMBOLS) {                                \
     /* decode remaining bits by tree traversal */                       \
     i = MSZIP_##tbl##_TABLEBITS - 1;					\
     do {                                                                \
       /* check next bit. error if we run out of bits before decode */	\
       if (i++ > MSZIP_MAX_HUFFBITS) {					\
         cli_dbgmsg("zip_inflate: out of bits in huffman decode\n");	\
         return INF_ERR_HUFFSYM;                                         \
       }                                                                 \
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       sym = (sym << 1) | ((bit_buffer >> i) & 1);			\
       if(sym >= MSZIP_##tbl##_TABLESIZE) {				\
 	cli_dbgmsg("zip_inflate: index out of table\n");		\
         return INF_ERR_HUFFSYM;                                         \
       }									\
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       /* double node index and add 0 (left branch) or 1 (right) */	\
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       sym = zip->tbl##_table[sym];					\
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       /* while we are still in node indicies, not decoded symbols */    \
     } while (sym >= MSZIP_##tbl##_MAXSYMBOLS);                          \
   }                                                                     \
   /* result */                                                          \
   (var) = sym;                                                          \
   /* look up the code length of that symbol and discard those bits */   \
   i = zip->tbl##_len[sym];                                              \
   MSZIP_REMOVE_BITS(i);                                                       \
 } while (0)
 
 static int mszip_read_lens(struct mszip_stream *zip) {
   /* for the bit buffer and huffman decoding */
   register unsigned int bit_buffer;
   register int bits_left;
   unsigned char *i_ptr, *i_end;
 
   /* bitlen Huffman codes -- immediate lookup, 7 bit max code length */
   unsigned short bl_table[(1 << 7)];
   unsigned char bl_len[19];
 
   unsigned char lens[MSZIP_LITERAL_MAXSYMBOLS + MSZIP_DISTANCE_MAXSYMBOLS];
   unsigned int lit_codes, dist_codes, code, last_code=0, bitlen_codes, i, run;
 
   MSZIP_RESTORE_BITS;
 
   /* read the number of codes */
   MSZIP_READ_BITS(lit_codes,    5); lit_codes    += 257;
   MSZIP_READ_BITS(dist_codes,   5); dist_codes   += 1;
   MSZIP_READ_BITS(bitlen_codes, 4); bitlen_codes += 4;
   if (lit_codes  > MSZIP_LITERAL_MAXSYMBOLS)  return INF_ERR_SYMLENS;
   if (dist_codes > MSZIP_DISTANCE_MAXSYMBOLS) return INF_ERR_SYMLENS;
 
   /* read in the bit lengths in their unusual order */
   for (i = 0; i < bitlen_codes; i++) MSZIP_READ_BITS(bl_len[mszip_bitlen_order[i]], 3);
   while (i < 19) bl_len[mszip_bitlen_order[i++]] = 0;
 
   /* create decoding table with an immediate lookup */
   if (mszip_make_decode_table(19, 7, &bl_len[0], &bl_table[0])) {
     return INF_ERR_BITLENTBL;
   }
 
   /* read literal / distance code lengths */
   for (i = 0; i < (lit_codes + dist_codes); i++) {
     /* single-level huffman lookup */
     MSZIP_ENSURE_BITS(7);
     code = bl_table[MSZIP_PEEK_BITS(7)];
     MSZIP_REMOVE_BITS(bl_len[code]);
 
     if (code < 16) lens[i] = last_code = code;
     else {
       switch (code) {
       case 16: MSZIP_READ_BITS(run, 2); run += 3;  code = last_code; break;
       case 17: MSZIP_READ_BITS(run, 3); run += 3;  code = 0;         break;
       case 18: MSZIP_READ_BITS(run, 7); run += 11; code = 0;         break;
       default: cli_dbgmsg("zip_read_lens: bad code!: %u\n", code); return INF_ERR_BADBITLEN;
       }
       if ((i + run) > (lit_codes + dist_codes)) return INF_ERR_BITOVERRUN;
       while (run--) lens[i++] = code;
       i--;
     }
   }
 
   /* copy LITERAL code lengths and clear any remaining */
   i = lit_codes;
   memcpy(&zip->LITERAL_len[0], &lens[0], i);
   while (i < MSZIP_LITERAL_MAXSYMBOLS) zip->LITERAL_len[i++] = 0;
 
   i = dist_codes;
   memcpy(&zip->DISTANCE_len[0], &lens[lit_codes], i);
   while (i < MSZIP_DISTANCE_MAXSYMBOLS) zip->DISTANCE_len[i++] = 0;
 
   MSZIP_STORE_BITS;
   return 0;
 }
 
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 static int mspack_write(int fd, const void *buff, unsigned int count, struct cab_file *file)
 {
 	int ret;
 
     if(file->max_size) {
 	if(file->written_size >= file->max_size)
 	    return CL_BREAK;
 
 	if(file->written_size + count > file->max_size)
 	    count = file->max_size - file->written_size;
     }
     if((ret = cli_writen(fd, buff, count)) > 0)
 	file->written_size += ret;
 
     return (ret == -1) ? CL_EWRITE : CL_SUCCESS;
 }
 
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 /* a clean implementation of RFC 1951 / inflate */
 static int mszip_inflate(struct mszip_stream *zip) {
   unsigned int last_block, block_type, distance, length, this_run, i;
 
   /* for the bit buffer and huffman decoding */
   register unsigned int bit_buffer;
   register int bits_left;
   register unsigned short sym;
   unsigned char *i_ptr, *i_end;
 
   MSZIP_RESTORE_BITS;
 
   do {
     /* read in last block bit */
     MSZIP_READ_BITS(last_block, 1);
 
     /* read in block type */
     MSZIP_READ_BITS(block_type, 2);
 
     if (block_type == 0) {
       /* uncompressed block */
       unsigned char lens_buf[4];
 
       /* go to byte boundary */
       i = bits_left & 7; MSZIP_REMOVE_BITS(i);
 
       /* read 4 bytes of data, emptying the bit-buffer if necessary */
       for (i = 0; (bits_left >= 8); i++) {
 	if (i == 4) return INF_ERR_BITBUF;
 	lens_buf[i] = MSZIP_PEEK_BITS(8);
 	MSZIP_REMOVE_BITS(8);
       }
       if (bits_left != 0) return INF_ERR_BITBUF;
       while (i < 4) {
 	if (i_ptr >= i_end) {
 	  if (mszip_read_input(zip)) return zip->error;
 	  i_ptr = zip->i_ptr;
 	  i_end = zip->i_end;
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 	  if(i_ptr == i_end) break;
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 	}
 	lens_buf[i++] = *i_ptr++;
       }
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       if (i < 4) return INF_ERR_BITBUF;
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       /* get the length and its complement */
       length = lens_buf[0] | (lens_buf[1] << 8);
       i      = lens_buf[2] | (lens_buf[3] << 8);
       if (length != (~i & 0xFFFF)) return INF_ERR_COMPLEMENT;
 
       /* read and copy the uncompressed data into the window */
       while (length > 0) {
 	if (i_ptr >= i_end) {
 	  if (mszip_read_input(zip)) return zip->error;
 	  i_ptr = zip->i_ptr;
 	  i_end = zip->i_end;
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 	  if(i_ptr == i_end) break;
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 	}
 
 	this_run = length;
 	if (this_run > (unsigned int)(i_end - i_ptr)) this_run = i_end - i_ptr;
 	if (this_run > (MSZIP_FRAME_SIZE - zip->window_posn))
 	  this_run = MSZIP_FRAME_SIZE - zip->window_posn;
 
 	memcpy(&zip->window[zip->window_posn], i_ptr, this_run);
 	zip->window_posn += this_run;
 	i_ptr    += this_run;
 	length   -= this_run;
 
 	if (zip->window_posn == MSZIP_FRAME_SIZE) {
 	  if (zip->flush_window(zip, MSZIP_FRAME_SIZE)) return INF_ERR_FLUSH;
 	  zip->window_posn = 0;
 	}
       }
     }
     else if ((block_type == 1) || (block_type == 2)) {
       /* Huffman-compressed LZ77 block */
       unsigned int window_posn, match_posn, code;
 
       if (block_type == 1) {
 	/* block with fixed Huffman codes */
 	i = 0;
 	while (i < 144) zip->LITERAL_len[i++] = 8;
 	while (i < 256) zip->LITERAL_len[i++] = 9;
 	while (i < 280) zip->LITERAL_len[i++] = 7;
 	while (i < 288) zip->LITERAL_len[i++] = 8;
 	for (i = 0; i < 32; i++) zip->DISTANCE_len[i] = 5;
       }
       else {
 	/* block with dynamic Huffman codes */
 	MSZIP_STORE_BITS;
 	if ((i = mszip_read_lens(zip))) return i;
 	MSZIP_RESTORE_BITS;
       }
 
       /* now huffman lengths are read for either kind of block, 
        * create huffman decoding tables */
       if (mszip_make_decode_table(MSZIP_LITERAL_MAXSYMBOLS, MSZIP_LITERAL_TABLEBITS,
 			    &zip->LITERAL_len[0], &zip->LITERAL_table[0]))
       {
 	return INF_ERR_LITERALTBL;
       }
 
       if (mszip_make_decode_table(MSZIP_DISTANCE_MAXSYMBOLS,MSZIP_DISTANCE_TABLEBITS,
 			    &zip->DISTANCE_len[0], &zip->DISTANCE_table[0]))
       {
 	return INF_ERR_DISTANCETBL;
       }
 
       /* decode forever until end of block code */
       window_posn = zip->window_posn;
       while (1) {
 	MSZIP_READ_HUFFSYM(LITERAL, code);
 	if (code < 256) {
 	  zip->window[window_posn++] = (unsigned char) code;
 	  if (window_posn == MSZIP_FRAME_SIZE) {
 	    if (zip->flush_window(zip, MSZIP_FRAME_SIZE)) return INF_ERR_FLUSH;
 	    window_posn = 0;
 	  }
 	}
 	else if (code == 256) {
 	  /* END OF BLOCK CODE: loop break point */
 	  break;
 	}
 	else {
 	  code -= 257;
 	  if (code > 29) return INF_ERR_LITCODE;
 	  MSZIP_READ_BITS_T(length, mszip_lit_extrabits[code]);
 	  length += mszip_lit_lengths[code];
 
 	  MSZIP_READ_HUFFSYM(DISTANCE, code);
 	  if (code > 30) return INF_ERR_DISTCODE;
 	  MSZIP_READ_BITS_T(distance, mszip_dist_extrabits[code]);
 	  distance += mszip_dist_offsets[code];
 
 	  /* match position is window position minus distance. If distance
 	   * is more than window position numerically, it must 'wrap
 	   * around' the frame size. */ 
 	  match_posn = ((distance > window_posn) ? MSZIP_FRAME_SIZE : 0)
 	    + window_posn - distance;
 
 	  /* copy match */
 	  if (length < 12) {
 	    /* short match, use slower loop but no loop setup code */
 	    while (length--) {
 	      zip->window[window_posn++] = zip->window[match_posn++];
 	      match_posn &= MSZIP_FRAME_SIZE - 1;
 
 	      if (window_posn == MSZIP_FRAME_SIZE) {
 		if (zip->flush_window(zip, MSZIP_FRAME_SIZE))
 		  return INF_ERR_FLUSH;
 		window_posn = 0;
 	      }
 	    }
 	  }
 	  else {
 	    /* longer match, use faster loop but with setup expense */
 	    unsigned char *runsrc, *rundest;
 	    do {
 	      this_run = length;
 	      if ((match_posn + this_run) > MSZIP_FRAME_SIZE)
 		this_run = MSZIP_FRAME_SIZE - match_posn;
 	      if ((window_posn + this_run) > MSZIP_FRAME_SIZE)
 		this_run = MSZIP_FRAME_SIZE - window_posn;
 
 	      rundest = &zip->window[window_posn]; window_posn += this_run;
 	      runsrc  = &zip->window[match_posn];  match_posn  += this_run;
 	      length -= this_run;
 	      while (this_run--) *rundest++ = *runsrc++;
 
 	      /* flush if necessary */
 	      if (window_posn == MSZIP_FRAME_SIZE) {
 		if (zip->flush_window(zip, MSZIP_FRAME_SIZE))
 		  return INF_ERR_FLUSH;
 		window_posn = 0;
 	      }
 	      if (match_posn == MSZIP_FRAME_SIZE) match_posn = 0;
 	    } while (length > 0);
 	  }
 
 	} /* else (code >= 257) */
 
       } /* while (forever) -- break point at 'code == 256' */
       zip->window_posn = window_posn;
     }
     else {
       /* block_type == 3 -- bad block type */
       return INF_ERR_BLOCKTYPE;
     }
   } while (!last_block);
 
   /* flush the remaining data */
   if (zip->window_posn) {
     if (zip->flush_window(zip, zip->window_posn)) return INF_ERR_FLUSH;
   }
   MSZIP_STORE_BITS;
 
   /* return success */
   return 0;
 }
 
 /* inflate() calls this whenever the window should be flushed. As
  * MSZIP only expands to the size of the window, the implementation used
  * simply keeps track of the amount of data flushed, and if more than 32k
  * is flushed, an error is raised.
  */  
 static int mszip_flush_window(struct mszip_stream *zip,
 			       unsigned int data_flushed)
 {
   zip->bytes_output += data_flushed;
   if (zip->bytes_output > MSZIP_FRAME_SIZE) {
     cli_dbgmsg("mszip_flush_window: overflow: %u bytes flushed, total is now %u\n", data_flushed, zip->bytes_output);
     return 1;
   }
   return 0;
 }
 
 struct mszip_stream *mszip_init(int fd,
 				  int ofd,
 				  int input_buffer_size,
 				  int repair_mode,
 				  struct cab_file *file,
649387c2
 			          int (*read_cb)(struct cab_file *, unsigned char *, int))
24fd05e1
 {
   struct mszip_stream *zip;
 
   input_buffer_size = (input_buffer_size + 1) & -2;
   if (!input_buffer_size) return NULL;
 
   /* allocate decompression state */
e1f64911
   if (!(zip = cli_calloc(1, sizeof(struct mszip_stream)))) {
24fd05e1
     return NULL;
   }
 
   /* allocate input buffer */
   zip->inbuf  = cli_malloc((size_t) input_buffer_size);
   if (!zip->inbuf) {
     free(zip);
     return NULL;
   }
 
   /* initialise decompression state */
   zip->fd	       = fd;
   zip->ofd	       = ofd;
   zip->wflag	       = 1;
   zip->inbuf_size      = input_buffer_size;
   zip->error           = CL_SUCCESS;
   zip->repair_mode     = repair_mode;
   zip->flush_window    = &mszip_flush_window;
   zip->input_end       = 0;
 
   zip->i_ptr = zip->i_end = &zip->inbuf[0];
   zip->o_ptr = zip->o_end = NULL;
   zip->bit_buffer = 0; zip->bits_left = 0;
 
   zip->file = file;
649387c2
   zip->read_cb = read_cb;
24fd05e1
 
   return zip;
 }
 
 int mszip_decompress(struct mszip_stream *zip, off_t out_bytes) {
   /* for the bit buffer */
   register unsigned int bit_buffer;
   register int bits_left;
   unsigned char *i_ptr, *i_end;
 
8df99a92
   int i, ret, state, error;
24fd05e1
 
   /* easy answers */
   if (!zip || (out_bytes < 0)) return CL_ENULLARG;
   if (zip->error) return zip->error;
 
   /* flush out any stored-up bytes before we begin */
   i = zip->o_end - zip->o_ptr;
   if ((off_t) i > out_bytes) i = (int) out_bytes;
   if (i) {
8df99a92
     if (zip->wflag && (ret = mspack_write(zip->ofd, zip->o_ptr, i, zip->file)) != CL_SUCCESS) {
       return zip->error = ret;
24fd05e1
     }
     zip->o_ptr  += i;
     out_bytes   -= i;
   }
   if (out_bytes == 0) return CL_SUCCESS;
 
   while (out_bytes > 0) {
     /* unpack another block */
     MSZIP_RESTORE_BITS;
 
     /* skip to next read 'CK' header */
     i = bits_left & 7; MSZIP_REMOVE_BITS(i); /* align to bytestream */
     state = 0;
     do {
       MSZIP_READ_BITS(i, 8);
       if (i == 'C') state = 1;
       else if ((state == 1) && (i == 'K')) state = 2;
       else state = 0;
     } while (state != 2);
 
     /* inflate a block, repair and realign if necessary */
     zip->window_posn = 0;
     zip->bytes_output = 0;
     MSZIP_STORE_BITS;
     if ((error = mszip_inflate(zip))) {
       cli_dbgmsg("mszip_decompress: inflate error %d\n", error);
       if (zip->repair_mode) {
 	cli_dbgmsg("mszip_decompress: MSZIP error, %u bytes of data lost\n",
 			  MSZIP_FRAME_SIZE - zip->bytes_output);
 	for (i = zip->bytes_output; i < MSZIP_FRAME_SIZE; i++) {
 	  zip->window[i] = '\0';
 	}
 	zip->bytes_output = MSZIP_FRAME_SIZE;
       }
       else {
 	return zip->error = (error > 0) ? error : CL_EFORMAT;
       }
     }
     zip->o_ptr = &zip->window[0];
     zip->o_end = &zip->o_ptr[zip->bytes_output];
 
     /* write a frame */
     i = (out_bytes < (off_t)zip->bytes_output) ?
       (int)out_bytes : zip->bytes_output;
8df99a92
     if (zip->wflag && (ret = mspack_write(zip->ofd, zip->o_ptr, i, zip->file)) != CL_SUCCESS) {
       return zip->error = ret;
24fd05e1
     }
 
     /* mspack errors (i.e. read errors) are fatal and can't be recovered */
     if ((error > 0) && zip->repair_mode) return error;
 
     zip->o_ptr  += i;
     out_bytes   -= i;
   }
 
   if (out_bytes) {
     cli_dbgmsg("mszip_decompress: bytes left to output\n");
     return zip->error = CL_EFORMAT;
   }
   return CL_SUCCESS;
 }
 
 void mszip_free(struct mszip_stream *zip) {
   if (zip) {
     free(zip->inbuf);
     free(zip);
   }
 }
 
 /***************************************************************************
  *			 LZX decompression implementation 
  ***************************************************************************
  * The LZX method was created by Jonathan Forbes and Tomi Poutanen, adapted
  * by Microsoft Corporation.
  *
  */
 
 /* LZX decompressor input macros
  *
  * LZX_STORE_BITS        stores bitstream state in lzx_stream structure
  * LZX_RESTORE_BITS      restores bitstream state from lzx_stream structure
  * LZX_READ_BITS(var,n)  takes N bits from the buffer and puts them in var
  * LZX_ENSURE_BITS(n)    ensures there are at least N bits in the bit buffer.
  * LZX_PEEK_BITS(n)      extracts without removing N bits from the bit buffer
  * LZX_REMOVE_BITS(n)    removes N bits from the bit buffer
  *
  */
 
 #define LZX_BITBUF_WIDTH (sizeof(bit_buffer) * CHAR_BIT)
 
 #define LZX_STORE_BITS do {                                                 \
   lzx->i_ptr      = i_ptr;                                              \
   lzx->i_end      = i_end;                                              \
   lzx->bit_buffer = bit_buffer;                                         \
   lzx->bits_left  = bits_left;                                          \
 } while (0)
 
 #define LZX_RESTORE_BITS do {                                               \
   i_ptr      = lzx->i_ptr;                                              \
   i_end      = lzx->i_end;                                              \
   bit_buffer = lzx->bit_buffer;                                         \
   bits_left  = lzx->bits_left;                                          \
 } while (0)
 
 #define LZX_ENSURE_BITS(nbits)                                              \
   while (bits_left < (nbits)) {                                         \
12bd9894
     if (i_ptr + 1 >= i_end) {                                               \
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       if (lzx_read_input(lzx)) return lzx->error;                      \
       i_ptr = lzx->i_ptr;                                               \
       i_end = lzx->i_end;                                               \
     }                                                                   \
     bit_buffer |= ((i_ptr[1] << 8) | i_ptr[0])                          \
                   << (LZX_BITBUF_WIDTH - 16 - bits_left);                   \
     bits_left  += 16;                                                   \
     i_ptr      += 2;                                                    \
   }
 
 #define LZX_PEEK_BITS(nbits) (bit_buffer >> (LZX_BITBUF_WIDTH - (nbits)))
 
 #define LZX_REMOVE_BITS(nbits) ((bit_buffer <<= (nbits)), (bits_left -= (nbits)))
 
 #define LZX_READ_BITS(val, nbits) do {                                      \
   LZX_ENSURE_BITS(nbits);                                                   \
   (val) = LZX_PEEK_BITS(nbits);                                             \
   LZX_REMOVE_BITS(nbits);                                                   \
 } while (0)
 
 static int lzx_read_input(struct lzx_stream *lzx) {
649387c2
   int bread = lzx->read_cb ? lzx->read_cb(lzx->file, &lzx->inbuf[0], (int)lzx->inbuf_size) : cli_readn(lzx->fd, &lzx->inbuf[0], (int)lzx->inbuf_size);
72ce4b70
   if (bread < 0) {
     if (lzx->file->error == CL_BREAK)
       return lzx->error = CL_BREAK;
     else
       return lzx->error = CL_EFORMAT;
   }
24fd05e1
 
   /* huff decode's ENSURE_BYTES(16) might overrun the input stream, even
    * if those bits aren't used, so fake 2 more bytes */
   if (bread == 0) {
     if (lzx->input_end) {
       cli_dbgmsg("lzx_read_input: out of input bytes\n");
871177cd
       return lzx->error = CL_EREAD;
24fd05e1
     }
     else {
       bread = 2;
       lzx->inbuf[0] = lzx->inbuf[1] = 0;
       lzx->input_end = 1;
     }
   }
 
   lzx->i_ptr = &lzx->inbuf[0];
   lzx->i_end = &lzx->inbuf[bread];
 
   return CL_SUCCESS;
 }
 
 /* Huffman decoding macros */
 
 /* LZX_READ_HUFFSYM(tablename, var) decodes one huffman symbol from the
  * bitstream using the stated table and puts it in var.
  */
 #define LZX_READ_HUFFSYM(tbl, var) do {                                     \
   /* huffman symbols can be up to 16 bits long */                       \
   LZX_ENSURE_BITS(16);                                                      \
   /* immediate table lookup of [tablebits] bits of the code */          \
   sym = lzx->tbl##_table[LZX_PEEK_BITS(LZX_##tbl##_TABLEBITS)];             \
   /* is the symbol is longer than [tablebits] bits? (i=node index) */   \
   if (sym >= LZX_##tbl##_MAXSYMBOLS) {                                  \
     /* decode remaining bits by tree traversal */                       \
     i = 1 << (LZX_BITBUF_WIDTH - LZX_##tbl##_TABLEBITS);                    \
     do {                                                                \
       /* one less bit. error if we run out of bits before decode */     \
       i >>= 1;                                                          \
       if (i == 0) {                                                     \
         cli_dbgmsg("lzx: out of bits in huffman decode\n");             \
         return lzx->error = CL_EFORMAT;					\
       }                                                                 \
       /* double node index and add 0 (left branch) or 1 (right) */      \
       sym <<= 1; sym |= (bit_buffer & i) ? 1 : 0;                       \
       /* hop to next node index / decoded symbol */                     \
240eab63
       if(sym >= (1 << LZX_##tbl##_TABLEBITS) + (LZX_##tbl##_MAXSYMBOLS * 2)) { \
 	cli_dbgmsg("lzx: index out of table\n");			\
 	return lzx->error = CL_EFORMAT;					\
       }									\
       sym = lzx->tbl##_table[sym];                                    \
24fd05e1
       /* while we are still in node indicies, not decoded symbols */    \
     } while (sym >= LZX_##tbl##_MAXSYMBOLS);                            \
   }                                                                     \
   /* result */                                                          \
   (var) = sym;                                                          \
   /* look up the code length of that symbol and discard those bits */   \
   i = lzx->tbl##_len[sym];                                              \
   LZX_REMOVE_BITS(i);                                                       \
 } while (0)
 
 /* LZX_BUILD_TABLE(tbl) builds a huffman lookup table from code lengths */
 #define LZX_BUILD_TABLE(tbl)                                                \
   if (lzx_make_decode_table(LZX_##tbl##_MAXSYMBOLS, LZX_##tbl##_TABLEBITS,  \
 			&lzx->tbl##_len[0], &lzx->tbl##_table[0]))      \
   {                                                                     \
     cli_dbgmsg("lzx: failed to build %s table\n", #tbl);                \
     return lzx->error = CL_EFORMAT;					\
   }
 
 /* lzx_make_decode_table(nsyms, nbits, length[], table[])
  *
  * This function was coded by David Tritscher. It builds a fast huffman
  * decoding table from 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 lzx_make_decode_table(unsigned int nsyms, unsigned int nbits,
 			     unsigned char *length, unsigned short *table)
 {
   register unsigned short sym;
   register unsigned int leaf, fill;
   register unsigned char bit_num;
   unsigned int pos         = 0; /* the current position in the decode table */
   unsigned int table_mask  = 1 << nbits;
   unsigned int bit_mask    = table_mask >> 1; /* don't do 0 length codes */
   unsigned int next_symbol = bit_mask; /* base of allocation for long codes */
 
   /* fill entries for codes short enough for a direct mapping */
   for (bit_num = 1; bit_num <= nbits; bit_num++) {
     for (sym = 0; sym < nsyms; sym++) {
       if (length[sym] != bit_num) continue;
       leaf = pos;
       if((pos += bit_mask) > table_mask) return 1; /* table overrun */
       /* fill all possible lookups of this symbol with the symbol itself */
       for (fill = bit_mask; fill-- > 0;) table[leaf++] = sym;
     }
     bit_mask >>= 1;
   }
 
   /* full table already? */
   if (pos == table_mask) return 0;
 
   /* clear the remainder of the table */
   for (sym = pos; sym < table_mask; sym++) table[sym] = 0xFFFF;
 
   /* allow codes to be up to nbits+16 long, instead of nbits */
   pos <<= 16;
   table_mask <<= 16;
   bit_mask = 1 << 15;
 
   for (bit_num = nbits+1; bit_num <= 16; bit_num++) {
     for (sym = 0; sym < nsyms; sym++) {
       if (length[sym] != bit_num) continue;
 
       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] == 0xFFFF) {
 	  table[(next_symbol << 1)] = 0xFFFF;
 	  table[(next_symbol << 1) + 1] = 0xFFFF;
 	  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;
   }
 
   /* 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;
 }
 
 /* LZX_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 LZX_READ_LENGTHS(tbl, first, last) do {                            \
   LZX_STORE_BITS;                                                          \
   if (lzx_read_lens(lzx, &lzx->tbl##_len[0], (first),                 \
     (unsigned int)(last))) return lzx->error;                          \
   LZX_RESTORE_BITS;                                                        \
 } while (0)
 
 static int lzx_read_lens(struct lzx_stream *lzx, unsigned char *lens,
 			  unsigned int first, unsigned int last)
 {
   /* bit buffer and huffman symbol decode variables */
   register unsigned int bit_buffer;
   register int bits_left, i;
   register unsigned short sym;
   unsigned char *i_ptr, *i_end;
 
   unsigned int x, y;
   int z;
 
   LZX_RESTORE_BITS;
   
   /* read lengths for pretree (20 symbols, lengths stored in fixed 4 bits) */
   for (x = 0; x < 20; x++) {
     LZX_READ_BITS(y, 4);
     lzx->PRETREE_len[x] = y;
   }
   LZX_BUILD_TABLE(PRETREE);
 
   for (x = first; x < last; ) {
     LZX_READ_HUFFSYM(PRETREE, z);
     if (z == 17) {
       /* code = 17, run of ([read 4 bits]+4) zeros */
       LZX_READ_BITS(y, 4); y += 4;
       while (y--) lens[x++] = 0;
     }
     else if (z == 18) {
       /* code = 18, run of ([read 5 bits]+20) zeros */
       LZX_READ_BITS(y, 5); y += 20;
       while (y--) lens[x++] = 0;
     }
     else if (z == 19) {
       /* code = 19, run of ([read 1 bit]+4) [read huffman symbol] */
       LZX_READ_BITS(y, 1); y += 4;
       LZX_READ_HUFFSYM(PRETREE, z);
       z = lens[x] - z; if (z < 0) z += 17;
       while (y--) lens[x++] = z;
     }
     else {
       /* code = 0 to 16, delta current length entry */
       z = lens[x] - z; if (z < 0) z += 17;
       lens[x++] = z;
     }
   }
 
   LZX_STORE_BITS;
 
   return CL_SUCCESS;
 }
 
 static void lzx_reset_state(struct lzx_stream *lzx) {
   int i;
 
   lzx->R0              = 1;
   lzx->R1              = 1;
   lzx->R2              = 1;
   lzx->header_read     = 0;
   lzx->block_remaining = 0;
   lzx->block_type      = LZX_BLOCKTYPE_INVALID;
 
   /* initialise tables to 0 (because deltas will be applied to them) */
   for (i = 0; i < LZX_MAINTREE_MAXSYMBOLS; i++) lzx->MAINTREE_len[i] = 0;
   for (i = 0; i < LZX_LENGTH_MAXSYMBOLS; i++)   lzx->LENGTH_len[i]   = 0;
 }
 
 /*-------- main LZX code --------*/
 
 struct lzx_stream *lzx_init(int fd,
 			      int ofd,
 			      int window_bits,
 			      int reset_interval,
 			      int input_buffer_size,
 			      off_t output_length,
 			      struct cab_file *file,
649387c2
 			      int (*read_cb)(struct cab_file *, unsigned char *, int))
24fd05e1
 {
   unsigned int window_size = 1 << window_bits;
   struct lzx_stream *lzx;
   int i, j;
 
   /* LZX supports window sizes of 2^15 (32Kb) through 2^21 (2Mb) */
   if (window_bits < 15 || window_bits > 21) return NULL;
 
   input_buffer_size = (input_buffer_size + 1) & -2;
   if (!input_buffer_size) return NULL;
 
   /* allocate decompression state */
   if (!(lzx = cli_calloc(1, sizeof(struct lzx_stream)))) {
     return NULL;
   }
 
   for (i = 0, j = 0; i < 51; i += 2) {
     lzx->extra_bits[i]   = j; /* 0,0,0,0,1,1,2,2,3,3,4,4,5,5,6,6,7,7... */
     if(i < 50)
 	lzx->extra_bits[i+1] = j;
     if ((i != 0) && (j < 17)) j++; /* 0,0,1,2,3,4...15,16,17,17,17,17... */
   }
 
   for (i = 0, j = 0; i < 51; i++) {
     lzx->position_base[i] = j; /* 0,1,2,3,4,6,8,12,16,24,32,... */
     j += 1 << lzx->extra_bits[i]; /* 1,1,1,1,2,2,4,4,8,8,16,16,32,32,... */
   }
 
   /* allocate decompression window and input buffer */
   lzx->window = cli_calloc(1, (size_t) window_size);
   if(!lzx->window) {
     free(lzx);
     return NULL;
   }
 
   lzx->inbuf  = cli_calloc(1, (size_t) input_buffer_size);
   if (!lzx->inbuf) {
     free(lzx->window);
     free(lzx);
     return NULL;
   }
 
   /* initialise decompression state */
   lzx->fd              = fd;
   lzx->ofd	       = ofd;
   lzx->wflag	       = 1;
   lzx->offset          = 0;
   lzx->length          = output_length;
   lzx->file	       = file;
649387c2
   lzx->read_cb	       = read_cb;
24fd05e1
 
   lzx->inbuf_size      = input_buffer_size;
   lzx->window_size     = 1 << window_bits;
   lzx->window_posn     = 0;
   lzx->frame_posn      = 0;
   lzx->frame           = 0;
   lzx->reset_interval  = reset_interval;
   lzx->intel_filesize  = 0;
   lzx->intel_curpos    = 0;
 
   /* window bits:    15  16  17  18  19  20  21
    * position slots: 30  32  34  36  38  42  50  */
   lzx->posn_slots      = ((window_bits == 21) ? 50 :
 			  ((window_bits == 20) ? 42 : (window_bits << 1)));
   lzx->intel_started   = 0;
   lzx->input_end       = 0;
 
   lzx->error = CL_SUCCESS;
 
   lzx->i_ptr = lzx->i_end = &lzx->inbuf[0];
   lzx->o_ptr = lzx->o_end = &lzx->e8_buf[0];
   lzx->bit_buffer = lzx->bits_left = 0;
 
   lzx_reset_state(lzx);
   return lzx;
 }
 
 void lzx_set_output_length(struct lzx_stream *lzx, off_t out_bytes) {
   if (lzx) lzx->length = out_bytes;
 }
 
 int lzx_decompress(struct lzx_stream *lzx, off_t out_bytes) {
   /* bitstream reading and huffman variables */
   register unsigned int bit_buffer;
   register int bits_left, i=0;
   register unsigned short sym;
   unsigned char *i_ptr, *i_end;
 
   int match_length, length_footer, extra, verbatim_bits, bytes_todo;
8df99a92
   int this_run, main_element, aligned_bits, j, ret;
24fd05e1
   unsigned char *window, *runsrc, *rundest, buf[12];
   unsigned int frame_size=0, end_frame, match_offset, window_posn;
   unsigned int R0, R1, R2;
 
   /* easy answers */
   if (!lzx || (out_bytes < 0)) return CL_ENULLARG;
   if (lzx->error) return lzx->error;
 
   /* flush out any stored-up bytes before we begin */
   i = lzx->o_end - lzx->o_ptr;
   if ((off_t) i > out_bytes) i = (int) out_bytes;
   if (i) {
8df99a92
     if (lzx->wflag && (ret = mspack_write(lzx->ofd, lzx->o_ptr, i, lzx->file)) != CL_SUCCESS) {
       return lzx->error = ret;
24fd05e1
     }
     lzx->o_ptr  += i;
     lzx->offset += i;
     out_bytes   -= i;
   }
   if (out_bytes == 0) return CL_SUCCESS;
 
   /* restore local state */
   LZX_RESTORE_BITS;
   window = lzx->window;
   window_posn = lzx->window_posn;
   R0 = lzx->R0;
   R1 = lzx->R1;
   R2 = lzx->R2;
 
   end_frame = (unsigned int)((lzx->offset + out_bytes) / LZX_FRAME_SIZE) + 1;
 
   while (lzx->frame < end_frame) {
     /* have we reached the reset interval? (if there is one?) */
     if (lzx->reset_interval && ((lzx->frame % lzx->reset_interval) == 0)) {
       if (lzx->block_remaining) {
 	cli_dbgmsg("lzx_decompress: %d bytes remaining at reset interval\n", lzx->block_remaining);
 	return lzx->error = CL_EFORMAT;
       }
 
       /* re-read the intel header and reset the huffman lengths */
       lzx_reset_state(lzx);
     }
 
     /* read header if necessary */
     if (!lzx->header_read) {
       /* read 1 bit. if bit=0, intel filesize = 0.
        * if bit=1, read intel filesize (32 bits) */
       j = 0; LZX_READ_BITS(i, 1); if (i) { LZX_READ_BITS(i, 16); LZX_READ_BITS(j, 16); }
       lzx->intel_filesize = (i << 16) | j;
       lzx->header_read = 1;
     } 
 
     /* calculate size of frame: all frames are 32k except the final frame
      * which is 32kb or less. this can only be calculated when lzx->length
      * has been filled in. */
     frame_size = LZX_FRAME_SIZE;
     if (lzx->length && (lzx->length - lzx->offset) < (off_t)frame_size) {
       frame_size = lzx->length - lzx->offset;
     }
 
     /* decode until one more frame is available */
     bytes_todo = lzx->frame_posn + frame_size - window_posn;
     while (bytes_todo > 0) {
       /* initialise new block, if one is needed */
       if (lzx->block_remaining == 0) {
 	/* realign if previous block was an odd-sized UNCOMPRESSED block */
 	if ((lzx->block_type == LZX_BLOCKTYPE_UNCOMPRESSED) &&
 	    (lzx->block_length & 1))
 	{
 	  if (i_ptr == i_end) {
 	    if (lzx_read_input(lzx)) return lzx->error;
 	    i_ptr = lzx->i_ptr;
 	    i_end = lzx->i_end;
 	  }
 	  i_ptr++;
 	}
 
 	/* read block type (3 bits) and block length (24 bits) */
 	LZX_READ_BITS(lzx->block_type, 3);
 	LZX_READ_BITS(i, 16); LZX_READ_BITS(j, 8);
 	lzx->block_remaining = lzx->block_length = (i << 8) | j;
 
 	/* read individual block headers */
 	switch (lzx->block_type) {
 	case LZX_BLOCKTYPE_ALIGNED:
 	  /* read lengths of and build aligned huffman decoding tree */
 	  for (i = 0; i < 8; i++) { LZX_READ_BITS(j, 3); lzx->ALIGNED_len[i] = j; }
 	  LZX_BUILD_TABLE(ALIGNED);
 	  /* no break -- rest of aligned header is same as verbatim */
 	case LZX_BLOCKTYPE_VERBATIM:
 	  /* read lengths of and build main huffman decoding tree */
 	  LZX_READ_LENGTHS(MAINTREE, 0, 256);
 	  LZX_READ_LENGTHS(MAINTREE, 256, LZX_NUM_CHARS + (lzx->posn_slots << 3));
 	  LZX_BUILD_TABLE(MAINTREE);
 	  /* if the literal 0xE8 is anywhere in the block... */
 	  if (lzx->MAINTREE_len[0xE8] != 0) lzx->intel_started = 1;
 	  /* read lengths of and build lengths huffman decoding tree */
 	  LZX_READ_LENGTHS(LENGTH, 0, LZX_NUM_SECONDARY_LENGTHS);
 	  LZX_BUILD_TABLE(LENGTH);
 	  break;
 
 	case LZX_BLOCKTYPE_UNCOMPRESSED:
 	  /* because we can't assume otherwise */
 	  lzx->intel_started = 1;
 
 	  /* read 1-16 (not 0-15) bits to align to bytes */
 	  LZX_ENSURE_BITS(16);
 	  if (bits_left > 16) i_ptr -= 2;
 	  bits_left = 0; bit_buffer = 0;
 
 	  /* read 12 bytes of stored R0 / R1 / R2 values */
 	  for (rundest = &buf[0], i = 0; i < 12; i++) {
 	    if (i_ptr == i_end) {
 	      if (lzx_read_input(lzx)) return lzx->error;
 	      i_ptr = lzx->i_ptr;
 	      i_end = lzx->i_end;
 	    }
 	    *rundest++ = *i_ptr++;
 	  }
 	  R0 = buf[0] | (buf[1] << 8) | (buf[2]  << 16) | (buf[3]  << 24);
 	  R1 = buf[4] | (buf[5] << 8) | (buf[6]  << 16) | (buf[7]  << 24);
 	  R2 = buf[8] | (buf[9] << 8) | (buf[10] << 16) | (buf[11] << 24);
 	  break;
 
 	default:
 	  cli_dbgmsg("lzx_decompress: bad block type (0x%x)\n", lzx->block_type);
 	  return lzx->error = CL_EFORMAT;
 	}
       }
 
       /* decode more of the block:
        * run = min(what's available, what's needed) */
       this_run = lzx->block_remaining;
       if (this_run > bytes_todo) this_run = bytes_todo;
 
       /* assume we decode exactly this_run bytes, for now */
       bytes_todo           -= this_run;
       lzx->block_remaining -= this_run;
 
       /* decode at least this_run bytes */
       switch (lzx->block_type) {
       case LZX_BLOCKTYPE_VERBATIM:
 	while (this_run > 0) {
 	  LZX_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;
 
 	    /* get match length */
 	    match_length = main_element & LZX_NUM_PRIMARY_LENGTHS;
 	    if (match_length == LZX_NUM_PRIMARY_LENGTHS) {
 	      LZX_READ_HUFFSYM(LENGTH, length_footer);
 	      match_length += length_footer;
 	    }
 	    match_length += LZX_MIN_MATCH;
 	  
 	    /* get match offset */
 	    switch ((match_offset = (main_element >> 3))) {
 	    case 0: match_offset = R0;                                  break;
 	    case 1: match_offset = R1; R1=R0;        R0 = match_offset; break;
 	    case 2: match_offset = R2; R2=R0;        R0 = match_offset; break;
 	    case 3: match_offset = 1;  R2=R1; R1=R0; R0 = match_offset; break;
 	    default:
 	      extra = lzx->extra_bits[match_offset];
 	      LZX_READ_BITS(verbatim_bits, extra);
 	      match_offset = lzx->position_base[match_offset] - 2 + verbatim_bits;
 	      R2 = R1; R1 = R0; R0 = match_offset;
 	    }
 
 	    if ((window_posn + match_length) > lzx->window_size) {
 	      cli_dbgmsg("lzx_decompress: match ran over window wrap\n");
 	      return lzx->error = CL_EFORMAT;
 	    }
 	    
 	    /* copy match */
 	    rundest = &window[window_posn];
 	    i = match_length;
 	    /* does match offset wrap the window? */
 	    if (match_offset > window_posn) {
 	      /* j = length from match offset to end of window */
 	      j = match_offset - window_posn;
 	      if (j > (int) lzx->window_size) {
 	        cli_dbgmsg("lzx_decompress: match offset beyond window boundaries\n");
 		return lzx->error = CL_EFORMAT;
 	      }
 	      runsrc = &window[lzx->window_size - j];
 	      if (j < i) {
 		/* if match goes over the window edge, do two copy runs */
 		i -= j; while (j-- > 0) *rundest++ = *runsrc++;
 		runsrc = window;
 	      }
 	      while (i-- > 0) *rundest++ = *runsrc++;
 	    }
 	    else {
 	      runsrc = rundest - match_offset;
5a1034b9
 	      if(i > (int) (lzx->window_size - window_posn))
17f74f9f
 	        i = lzx->window_size - window_posn;
24fd05e1
 	      while (i-- > 0) *rundest++ = *runsrc++;
 	    }
 
 	    this_run    -= match_length;
 	    window_posn += match_length;
 	  }
 	} /* while (this_run > 0) */
 	break;
 
       case LZX_BLOCKTYPE_ALIGNED:
 	while (this_run > 0) {
 	  LZX_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;
 
 	    /* get match length */
 	    match_length = main_element & LZX_NUM_PRIMARY_LENGTHS;
 	    if (match_length == LZX_NUM_PRIMARY_LENGTHS) {
 	      LZX_READ_HUFFSYM(LENGTH, length_footer);
 	      match_length += length_footer;
 	    }
 	    match_length += LZX_MIN_MATCH;
 
 	    /* get match offset */
 	    switch ((match_offset = (main_element >> 3))) {
 	    case 0: match_offset = R0;                             break;
 	    case 1: match_offset = R1; R1 = R0; R0 = match_offset; break;
 	    case 2: match_offset = R2; R2 = R0; R0 = match_offset; break;
 	    default:
 	      extra = lzx->extra_bits[match_offset];
 	      match_offset = lzx->position_base[match_offset] - 2;
 	      if (extra > 3) {
 		/* verbatim and aligned bits */
 		extra -= 3;
 		LZX_READ_BITS(verbatim_bits, extra);
 		match_offset += (verbatim_bits << 3);
 		LZX_READ_HUFFSYM(ALIGNED, aligned_bits);
 		match_offset += aligned_bits;
 	      }
 	      else if (extra == 3) {
 		/* aligned bits only */
 		LZX_READ_HUFFSYM(ALIGNED, aligned_bits);
 		match_offset += aligned_bits;
 	      }
 	      else if (extra > 0) { /* extra==1, extra==2 */
 		/* verbatim bits only */
 		LZX_READ_BITS(verbatim_bits, extra);
 		match_offset += verbatim_bits;
 	      }
 	      else /* extra == 0 */ {
 		/* ??? not defined in LZX specification! */
 		match_offset = 1;
 	      }
 	      /* update repeated offset LRU queue */
 	      R2 = R1; R1 = R0; R0 = match_offset;
 	    }
 
 	    if ((window_posn + match_length) > lzx->window_size) {
 	      cli_dbgmsg("lzx_decompress: match ran over window wrap\n");
 	      return lzx->error = CL_EFORMAT;
 	    }
 
 	    /* copy match */
 	    rundest = &window[window_posn];
 	    i = match_length;
 	    /* does match offset wrap the window? */
 	    if (match_offset > window_posn) {
 	      /* j = length from match offset to end of window */
 	      j = match_offset - window_posn;
 	      if (j > (int) lzx->window_size) {
 	        cli_dbgmsg("lzx_decompress: match offset beyond window boundaries\n");
 		return lzx->error = CL_EFORMAT;
 	      }
 	      runsrc = &window[lzx->window_size - j];
 	      if (j < i) {
 		/* if match goes over the window edge, do two copy runs */
 		i -= j; while (j-- > 0) *rundest++ = *runsrc++;
 		runsrc = window;
 	      }
 	      while (i-- > 0) *rundest++ = *runsrc++;
 	    }
 	    else {
 	      runsrc = rundest - match_offset;
 	      while (i-- > 0) *rundest++ = *runsrc++;
 	    }
 
 	    this_run    -= match_length;
 	    window_posn += match_length;
 	  }
 	} /* while (this_run > 0) */
 	break;
 
       case LZX_BLOCKTYPE_UNCOMPRESSED:
 	/* as this_run is limited not to wrap a frame, this also means it
 	 * won't wrap the window (as the window is a multiple of 32k) */
 	rundest = &window[window_posn];
 	window_posn += this_run;
 	while (this_run > 0) {
 	  if ((i = i_end - i_ptr)) {
 	    if (i > this_run) i = this_run;
 	    memcpy(rundest, i_ptr, (size_t) i);
 	    rundest  += i;
 	    i_ptr    += i;
 	    this_run -= i;
 	  }
 	  else {
 	    if (lzx_read_input(lzx)) return lzx->error;
 	    i_ptr = lzx->i_ptr;
 	    i_end = lzx->i_end;
 	  }
 	}
 	break;
 
       default:
 	return lzx->error = CL_EFORMAT; /* might as well */
       }
 
       /* did the final match overrun our desired this_run length? */
       if (this_run < 0) {
 	if ((unsigned int)(-this_run) > lzx->block_remaining) {
 	  cli_dbgmsg("lzx_decompress: overrun went past end of block by %d (%d remaining)\n", -this_run, lzx->block_remaining);
 	  return lzx->error = CL_EFORMAT;
 	}
 	lzx->block_remaining -= -this_run;
       }
     } /* while (bytes_todo > 0) */
 
     /* streams don't extend over frame boundaries */
     if ((window_posn - lzx->frame_posn) != frame_size) {
       cli_dbgmsg("lzx_decompress: decode beyond output frame limits! %d != %d\n", window_posn - lzx->frame_posn, frame_size);
       return lzx->error = CL_EFORMAT;
     }
 
     /* re-align input bitstream */
     if (bits_left > 0) LZX_ENSURE_BITS(16);
     if (bits_left & 15) LZX_REMOVE_BITS(bits_left & 15);
 
     /* check that we've used all of the previous frame first */
     if (lzx->o_ptr != lzx->o_end) {
5cd3f734
       cli_dbgmsg("lzx_decompress: %ld avail bytes, new %d frame\n", lzx->o_end-lzx->o_ptr, frame_size);
24fd05e1
       return lzx->error = CL_EFORMAT;
     }
 
     /* does this intel block _really_ need decoding? */
     if (lzx->intel_started && lzx->intel_filesize &&
 	(lzx->frame <= 32768) && (frame_size > 10))
     {
       unsigned char *data    = &lzx->e8_buf[0];
       unsigned char *dataend = &lzx->e8_buf[frame_size - 10];
       signed int curpos      = lzx->intel_curpos;
       signed int filesize    = lzx->intel_filesize;
       signed int abs_off, rel_off;
 
       /* copy e8 block to the e8 buffer and tweak if needed */
       lzx->o_ptr = data;
       memcpy(data, &lzx->window[lzx->frame_posn], frame_size);
 
       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] = (unsigned char) rel_off;
 	  data[1] = (unsigned char) (rel_off >> 8);
 	  data[2] = (unsigned char) (rel_off >> 16);
 	  data[3] = (unsigned char) (rel_off >> 24);
 	}
 	data += 4;
 	curpos += 5;
       }
       lzx->intel_curpos += frame_size;
     }
     else {
       lzx->o_ptr = &lzx->window[lzx->frame_posn];
       if (lzx->intel_filesize) lzx->intel_curpos += frame_size;
     }
     lzx->o_end = &lzx->o_ptr[frame_size];
 
     /* write a frame */
     i = (out_bytes < (off_t)frame_size) ? (unsigned int)out_bytes : frame_size;
8df99a92
     if (lzx->wflag && (ret = mspack_write(lzx->ofd, lzx->o_ptr, i, lzx->file)) != CL_SUCCESS) {
       return lzx->error = ret;
24fd05e1
     }
     lzx->o_ptr  += i;
     lzx->offset += i;
     out_bytes   -= i;
 
     /* advance frame start position */
     lzx->frame_posn += frame_size;
     lzx->frame++;
 
     /* wrap window / frame position pointers */
     if (window_posn == lzx->window_size)     window_posn = 0;
     if (lzx->frame_posn == lzx->window_size) lzx->frame_posn = 0;
 
   } /* while (lzx->frame < end_frame) */
 
   if (out_bytes) {
     cli_dbgmsg("lzx_decompress: bytes left to output\n");
     return lzx->error = CL_EFORMAT;
   }
 
   /* store local state */
   LZX_STORE_BITS;
   lzx->window_posn = window_posn;
   lzx->R0 = R0;
   lzx->R1 = R1;
   lzx->R2 = R2;
 
   return CL_SUCCESS;
 }
 
 void lzx_free(struct lzx_stream *lzx) {
   if (lzx) {
     free(lzx->inbuf);
     free(lzx->window);
     free(lzx);
   }
 }
 
 /***************************************************************************
  *			 Quantum decompression implementation 
  ***************************************************************************
  * The Quantum method was created by David Stafford, adapted by Microsoft
  * Corporation.
  *
  * This decompressor is based on an implementation by Matthew Russotto, used
  * with permission.
  *
  * This decompressor was researched and implemented by Matthew Russotto. It
  * has since been tidied up by Stuart Caie. More information can be found at
  * http://www.speakeasy.org/~russotto/quantumcomp.html
  */
 
 /* Quantum decompressor bitstream reading macros
  *
  * QTM_STORE_BITS        stores bitstream state in qtm_stream structure
  * QTM_RESTORE_BITS      restores bitstream state from qtm_stream structure
  * QTM_READ_BITS(var,n)  takes N bits from the buffer and puts them in var
  * QTM_FILL_BUFFER       if there is room for another 16 bits, reads another
  *                   16 bits from the input stream.
  * QTM_PEEK_BITS(n)      extracts without removing N bits from the bit buffer
  * QTM_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.
  */
 
 #define QTM_BITBUF_WIDTH (sizeof(unsigned int) * CHAR_BIT)
 
 #define QTM_STORE_BITS do {                                                 \
   qtm->i_ptr      = i_ptr;                                              \
   qtm->i_end      = i_end;                                              \
   qtm->bit_buffer = bit_buffer;                                         \
   qtm->bits_left  = bits_left;                                          \
 } while (0)
 
 #define QTM_RESTORE_BITS do {                                               \
   i_ptr      = qtm->i_ptr;                                              \
   i_end      = qtm->i_end;                                              \
   bit_buffer = qtm->bit_buffer;                                         \
   bits_left  = qtm->bits_left;                                          \
 } while (0)
 
 /* adds 16 bits to bit buffer, if there's space for the new bits */
 #define QTM_FILL_BUFFER do {                                                \
   if (bits_left <= (QTM_BITBUF_WIDTH - 16)) {                               \
     if (i_ptr >= i_end) {                                               \
       if (qtm_read_input(qtm)) return qtm->error;                      \
       i_ptr = qtm->i_ptr;                                               \
       i_end = qtm->i_end;                                               \
     }                                                                   \
     bit_buffer |= ((i_ptr[0] << 8) | i_ptr[1])                          \
                   << (QTM_BITBUF_WIDTH - 16 - bits_left);                   \
     bits_left  += 16;                                                   \
     i_ptr      += 2;                                                    \
   }                                                                     \
 } while (0)
 
 #define QTM_PEEK_BITS(n)   (bit_buffer >> (QTM_BITBUF_WIDTH - (n)))
 #define QTM_REMOVE_BITS(n) ((bit_buffer <<= (n)), (bits_left -= (n)))
 
 #define QTM_READ_BITS(val, bits) do {                                       \
   (val) = 0;                                                            \
   for (bits_needed = (bits); bits_needed > 0; bits_needed -= bit_run) { \
     QTM_FILL_BUFFER;                                                        \
     bit_run = (bits_left < bits_needed) ? bits_left : bits_needed;      \
     (val) = ((val) << bit_run) | QTM_PEEK_BITS(bit_run);                    \
     QTM_REMOVE_BITS(bit_run);                                               \
   }                                                                     \
 } while (0)
 
 static int qtm_read_input(struct qtm_stream *qtm) {
649387c2
   int nread = qtm->read_cb ? qtm->read_cb(qtm->file, &qtm->inbuf[0], (int)qtm->inbuf_size) : cli_readn(qtm->fd, &qtm->inbuf[0], (int)qtm->inbuf_size);
72ce4b70
   if (nread < 0) {
     if (qtm->file->error == CL_BREAK)
       return qtm->error = CL_BREAK;
     else
       return qtm->error = CL_EFORMAT;
   }
24fd05e1
 
   qtm->i_ptr = &qtm->inbuf[0];
649387c2
   qtm->i_end = &qtm->inbuf[nread];
24fd05e1
   return CL_SUCCESS;
 }
 
 /* Arithmetic decoder:
  * 
  * QTM_GET_SYMBOL(model, var) fetches the next symbol from the stated model
  * and puts it in var.
  *
  * If necessary, qtm_update_model() is called.
  */
 #define QTM_GET_SYMBOL(model, var) do {                                     \
   range = ((H - L) & 0xFFFF) + 1;                                       \
   symf = ((((C - L + 1) * model.syms[0].cumfreq)-1) / range) & 0xFFFF;  \
                                                                         \
   for (i = 1; i < model.entries; i++) {                                 \
     if (model.syms[i].cumfreq <= symf) break;                           \
   }                                                                     \
   (var) = model.syms[i-1].sym;                                          \
                                                                         \
   range = (H - L) + 1;                                                  \
   symf = model.syms[0].cumfreq;                                         \
   H = L + ((model.syms[i-1].cumfreq * range) / symf) - 1;               \
   L = L + ((model.syms[i].cumfreq   * range) / symf);                   \
                                                                         \
   do { model.syms[--i].cumfreq += 8; } while (i > 0);                   \
   if (model.syms[0].cumfreq > 3800) qtm_update_model(&model);          \
                                                                         \
   while (1) {                                                           \
     if ((L & 0x8000) != (H & 0x8000)) {                                 \
       if ((L & 0x4000) && !(H & 0x4000)) {                              \
         /* underflow case */                                            \
         C ^= 0x4000; L &= 0x3FFF; H |= 0x4000;                          \
       }                                                                 \
       else break;                                                       \
     }                                                                   \
     L <<= 1; H = (H << 1) | 1;                                          \
     QTM_FILL_BUFFER;                                                        \
     C  = (C << 1) | QTM_PEEK_BITS(1);                                       \
     QTM_REMOVE_BITS(1);                                                     \
   }                                                                     \
 } while (0)
 
 static void qtm_update_model(struct qtm_model *model) {
   struct qtm_modelsym tmp;
   int i, j;
 
   if (--model->shiftsleft) {
     for (i = model->entries - 1; i >= 0; i--) {
       /* -1, not -2; the 0 entry saves this */
       model->syms[i].cumfreq >>= 1;
       if (model->syms[i].cumfreq <= model->syms[i+1].cumfreq) {
 	model->syms[i].cumfreq = model->syms[i+1].cumfreq + 1;
       }
     }
   }
   else {
     model->shiftsleft = 50;
     for (i = 0; i < model->entries; i++) {
       /* no -1, want to include the 0 entry */
       /* this converts cumfreqs into frequencies, then shifts right */
       model->syms[i].cumfreq -= model->syms[i+1].cumfreq;
       model->syms[i].cumfreq++; /* avoid losing things entirely */
       model->syms[i].cumfreq >>= 1;
     }
 
     /* now sort by frequencies, decreasing order -- this must be an
      * inplace selection sort, or a sort with the same (in)stability
      * characteristics */
     for (i = 0; i < model->entries - 1; i++) {
       for (j = i + 1; j < model->entries; j++) {
 	if (model->syms[i].cumfreq < model->syms[j].cumfreq) {
 	  tmp = model->syms[i];
 	  model->syms[i] = model->syms[j];
 	  model->syms[j] = tmp;
 	}
       }
     }
 
     /* then convert frequencies back to cumfreq */
     for (i = model->entries - 1; i >= 0; i--) {
       model->syms[i].cumfreq += model->syms[i+1].cumfreq;
     }
   }
 }
 
 /* Initialises a model to decode symbols from [start] to [start]+[len]-1 */
 static void qtm_init_model(struct qtm_model *model,
 			    struct qtm_modelsym *syms, int start, int len)
 {
   int i;
 
   model->shiftsleft = 4;
   model->entries    = len;
   model->syms       = syms;
 
   for (i = 0; i <= len; i++) {
     syms[i].sym     = start + i; /* actual symbol */
     syms[i].cumfreq = len - i;   /* current frequency of that symbol */
   }
 }
 
 
 /*-------- main Quantum code --------*/
 
 struct qtm_stream *qtm_init(int fd, int ofd,
 			      int window_bits, int input_buffer_size,
 			      struct cab_file *file,
649387c2
 			      int (*read_cb)(struct cab_file *, unsigned char *, int))
24fd05e1
 {
   unsigned int window_size = 1 << window_bits;
   struct qtm_stream *qtm;
   unsigned offset;
   int i;
 
   /* Quantum supports window sizes of 2^10 (1Kb) through 2^21 (2Mb) */
 
   /* tk: temporary fix: only process 32KB+ window sizes */
   if (window_bits < 15 || window_bits > 21) return NULL;
 
   input_buffer_size = (input_buffer_size + 1) & -2;
   if (input_buffer_size < 2) return NULL;
 
   /* allocate decompression state */
e1f64911
   if (!(qtm = cli_calloc(1, sizeof(struct qtm_stream)))) {
24fd05e1
     return NULL;
   }
 
   for (i = 0, offset = 0; i < 42; i++) {
     qtm->position_base[i] = offset;
     qtm->extra_bits[i] = ((i < 2) ? 0 : (i - 2)) >> 1;
     offset += 1 << qtm->extra_bits[i];
   }
 
   for (i = 0, offset = 0; i < 26; i++) {
     qtm->length_base[i] = offset;
     qtm->length_extra[i] = (i < 2 ? 0 : i - 2) >> 2;
     offset += 1 << qtm->length_extra[i];
   }
   qtm->length_base[26] = 254; qtm->length_extra[26] = 0;
 
   /* allocate decompression window and input buffer */
   qtm->window = cli_malloc((size_t) window_size);
   if (!qtm->window) {
     free(qtm);
     return NULL;
   }
 
   qtm->inbuf  = cli_malloc((size_t) input_buffer_size);
   if (!qtm->inbuf) {
     free(qtm->window);
     free(qtm);
     return NULL;
   }
 
   /* initialise decompression state */
   qtm->fd	   = fd;
   qtm->ofd	   = ofd;
   qtm->wflag	   = 1;
   qtm->inbuf_size  = input_buffer_size;
   qtm->window_size = window_size;
   qtm->window_posn = 0;
   qtm->frame_start = 0;
   qtm->header_read = 0;
   qtm->error       = CL_SUCCESS;
 
   qtm->i_ptr = qtm->i_end = &qtm->inbuf[0];
   qtm->o_ptr = qtm->o_end = &qtm->window[0];
   qtm->bits_left = 0;
   qtm->bit_buffer = 0;
 
   /* initialise arithmetic coding models
    * - model 4    depends on window size, ranges from 20 to 24
    * - model 5    depends on window size, ranges from 20 to 36
    * - model 6pos depends on window size, ranges from 20 to 42
    */
   i = window_bits * 2;
   qtm_init_model(&qtm->model0,    &qtm->m0sym[0],   0, 64);
   qtm_init_model(&qtm->model1,    &qtm->m1sym[0],  64, 64);
   qtm_init_model(&qtm->model2,    &qtm->m2sym[0], 128, 64);
   qtm_init_model(&qtm->model3,    &qtm->m3sym[0], 192, 64);
   qtm_init_model(&qtm->model4,    &qtm->m4sym[0],   0, (i > 24) ? 24 : i);
   qtm_init_model(&qtm->model5,    &qtm->m5sym[0],   0, (i > 36) ? 36 : i);
   qtm_init_model(&qtm->model6,    &qtm->m6sym[0],   0, i);
   qtm_init_model(&qtm->model6len, &qtm->m6lsym[0],  0, 27);
   qtm_init_model(&qtm->model7,    &qtm->m7sym[0],   0, 7);
 
   qtm->file = file;
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   qtm->read_cb = read_cb;
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   /* all ok */
   return qtm;
 }
 
 int qtm_decompress(struct qtm_stream *qtm, off_t out_bytes) {
   unsigned int frame_start, frame_end, window_posn, match_offset, range;
   unsigned char *window, *i_ptr, *i_end, *runsrc, *rundest;
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   int i, j, selector, extra, sym, match_length, ret;
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   unsigned short H, L, C, symf;
 
   register unsigned int bit_buffer;
   register unsigned char bits_left;
   unsigned char bits_needed, bit_run;
 
   /* easy answers */
   if (!qtm || (out_bytes < 0)) return CL_ENULLARG;
   if (qtm->error) return qtm->error;
 
   /* flush out any stored-up bytes before we begin */
   i = qtm->o_end - qtm->o_ptr;
   if ((off_t) i > out_bytes) i = (int) out_bytes;
   if (i) {
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     if (qtm->wflag && (ret = mspack_write(qtm->ofd, qtm->o_ptr, i, qtm->file)) != CL_SUCCESS) {
       return qtm->error = ret;
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     }
     qtm->o_ptr  += i;
     out_bytes   -= i;
   }
   if (out_bytes == 0) return CL_SUCCESS;
 
   /* restore local state */
   QTM_RESTORE_BITS;
   window = qtm->window;
   window_posn = qtm->window_posn;
   frame_start = qtm->frame_start;
   H = qtm->H;
   L = qtm->L;
   C = qtm->C;
 
   /* while we do not have enough decoded bytes in reserve: */
   while ((qtm->o_end - qtm->o_ptr) < out_bytes) {
 
     /* read header if necessary. Initialises H, L and C */
     if (!qtm->header_read) {
       H = 0xFFFF; L = 0; QTM_READ_BITS(C, 16);
       qtm->header_read = 1;
     }
 
     /* decode more, at most up to to frame boundary */
     frame_end = window_posn + (out_bytes - (qtm->o_end - qtm->o_ptr));
     if ((frame_start + QTM_FRAME_SIZE) < frame_end) {
       frame_end = frame_start + QTM_FRAME_SIZE;
     }
 
     while (window_posn < frame_end) {
       QTM_GET_SYMBOL(qtm->model7, selector);
       if (selector < 4) {
 	struct qtm_model *mdl = (selector == 0) ? &qtm->model0 :
 	                        ((selector == 1) ? &qtm->model1 :
 				((selector == 2) ? &qtm->model2 :
                                                    &qtm->model3));
 	QTM_GET_SYMBOL((*mdl), sym);
 	window[window_posn++] = sym;
       }
       else {
 	switch (selector) {
 	case 4: /* selector 4 = fixed length match (3 bytes) */
 	  QTM_GET_SYMBOL(qtm->model4, sym);
 	  QTM_READ_BITS(extra, qtm->extra_bits[sym]);
 	  match_offset = qtm->position_base[sym] + extra + 1;
 	  match_length = 3;
 	  break;
 
 	case 5: /* selector 5 = fixed length match (4 bytes) */
 	  QTM_GET_SYMBOL(qtm->model5, sym);
 	  QTM_READ_BITS(extra, qtm->extra_bits[sym]);
 	  match_offset = qtm->position_base[sym] + extra + 1;
 	  match_length = 4;
 	  break;
 
 	case 6: /* selector 6 = variable length match */
 	  QTM_GET_SYMBOL(qtm->model6len, sym);
 	  QTM_READ_BITS(extra, qtm->length_extra[sym]);
 	  match_length = qtm->length_base[sym] + extra + 5;
 
 	  QTM_GET_SYMBOL(qtm->model6, sym);
 	  QTM_READ_BITS(extra, qtm->extra_bits[sym]);
 	  match_offset = qtm->position_base[sym] + extra + 1;
 	  break;
 
 	default:
 	  /* should be impossible, model7 can only return 0-6 */
 	  return qtm->error = CL_EFORMAT;
 	}
 
 	rundest = &window[window_posn];
 	i = match_length;
 	/* does match offset wrap the window? */
 	if (match_offset > window_posn) {
 	  /* j = length from match offset to end of window */
 	  j = match_offset - window_posn;
 	  if (j > (int) qtm->window_size) {
 	    cli_dbgmsg("qtm_decompress: match offset beyond window boundaries\n");
 	    return qtm->error = CL_EFORMAT;
 	  }
 	  runsrc = &window[qtm->window_size - j];
 	  if (j < i) {
 	    /* if match goes over the window edge, do two copy runs */
 	    i -= j; while (j-- > 0) *rundest++ = *runsrc++;
 	    runsrc = window;
 	  }
 	  while (i-- > 0) *rundest++ = *runsrc++;
 	}
 	else {
 	  runsrc = rundest - match_offset;
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 	  if(i > (int) (qtm->window_size - window_posn))
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 	    i = qtm->window_size - window_posn;
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 	  while (i-- > 0) *rundest++ = *runsrc++;
 	}
 	window_posn += match_length;
       }
     } /* while (window_posn < frame_end) */
 
     qtm->o_end = &window[window_posn];
 
     /* another frame completed? */
     if ((window_posn - frame_start) >= QTM_FRAME_SIZE) {
       if ((window_posn - frame_start) != QTM_FRAME_SIZE) {
 	cli_dbgmsg("qtm_decompress: overshot frame alignment\n");
 	return qtm->error = CL_EFORMAT;
       }
 
       /* re-align input */
       if (bits_left & 7) QTM_REMOVE_BITS(bits_left & 7);
       do { QTM_READ_BITS(i, 8); } while (i != 0xFF);
       qtm->header_read = 0;
 
       /* window wrap? */
       if (window_posn == qtm->window_size) {
 	/* flush all currently stored data */
 	i = (qtm->o_end - qtm->o_ptr);
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 	if (qtm->wflag && (ret = mspack_write(qtm->ofd, qtm->o_ptr, i, qtm->file)) != CL_SUCCESS) {
 	  return qtm->error = ret;
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 	}
 	out_bytes -= i;
 	qtm->o_ptr = &window[0];
 	qtm->o_end = &window[0];
 	window_posn = 0;
       }
 
       frame_start = window_posn;
     }
 
   } /* while (more bytes needed) */
 
   if (out_bytes) {
     i = (int) out_bytes;
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     if (qtm->wflag && (ret = mspack_write(qtm->ofd, qtm->o_ptr, i, qtm->file)) != CL_SUCCESS) {
       return qtm->error = ret;
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     }
     qtm->o_ptr += i;
   }
 
   /* store local state */
   QTM_STORE_BITS;
   qtm->window_posn = window_posn;
   qtm->frame_start = frame_start;
   qtm->H = H;
   qtm->L = L;
   qtm->C = C;
 
   return CL_SUCCESS;
 }
 
 void qtm_free(struct qtm_stream *qtm) {
   if (qtm) {
     free(qtm->window);
     free(qtm->inbuf);
     free(qtm);
   }
 }