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/*

 * THIS FILE IS NOT IDENTICAL TO THE ORIGINAL

 * FROM THE BZIP2 DISTRIBUTION.

 *

 * It has been modified, mainly to break the library

 * into smaller pieces.

 *

 * Russ Cox

 * rsc@plan9.bell-labs.com

 * July 2000

 */

/*-------------------------------------------------------------*/

/*--- Library top-level functions.                          ---*/

/*---                                               bzlib.c ---*/

/*-------------------------------------------------------------*/

/*--

  This file is a part of bzip2 and/or libbzip2, a program and

  library for lossless, block-sorting data compression.

  Copyright (C) 1996-2000 Julian R Seward.  All rights reserved.

  Redistribution and use in source and binary forms, with or without

  modification, are permitted provided that the following conditions

  are met:

  1. Redistributions of source code must retain the above copyright

     notice, this list of conditions and the following disclaimer.

  2. The origin of this software must not be misrepresented; you must 

     not claim that you wrote the original software.  If you use this 

     software in a product, an acknowledgment in the product 

     documentation would be appreciated but is not required.

  3. Altered source versions must be plainly marked as such, and must

     not be misrepresented as being the original software.

  4. The name of the author may not be used to endorse or promote 

     products derived from this software without specific prior written 

     permission.

  THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS

  OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED

  WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

  ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY

  DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL

  DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE

  GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS

  INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,

  WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING

  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS

  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

  Julian Seward, Cambridge, UK.

  jseward@acm.org

  bzip2/libbzip2 version 1.0 of 21 March 2000

  This program is based on (at least) the work of:

     Mike Burrows

     David Wheeler

     Peter Fenwick

     Alistair Moffat

     Radford Neal

     Ian H. Witten

     Robert Sedgewick

     Jon L. Bentley

  For more information on these sources, see the manual.

--*/

/*--

   CHANGES

   ~~~~~~~

   0.9.0 -- original version.

   0.9.0a/b -- no changes in this file.

   0.9.0c

      * made zero-length BZ_FLUSH work correctly in bzCompress().

      * fixed bzWrite/bzRead to ignore zero-length requests.

      * fixed bzread to correctly handle read requests after EOF.

      * wrong parameter order in call to bzDecompressInit in

        bzBuffToBuffDecompress.  Fixed.

--*/

#include "os.h"

#include "bzlib.h"

#include "bzlib_private.h"

/*---------------------------------------------------*/

/*--- Decompression stuff                         ---*/

/*---------------------------------------------------*/

/*---------------------------------------------------*/

int BZ_API(BZ2_bzDecompressInit) 

                     ( bz_stream* strm, 

                       int        verbosity,

                       int        small )

{

   DState* s;

   if (!bz_config_ok()) return BZ_CONFIG_ERROR;

   if (strm == NULL) return BZ_PARAM_ERROR;

   if (small != 0 && small != 1) return BZ_PARAM_ERROR;

   if (verbosity < 0 || verbosity > 4) return BZ_PARAM_ERROR;

   if (strm->bzalloc == NULL) strm->bzalloc = default_bzalloc;

   if (strm->bzfree == NULL) strm->bzfree = default_bzfree;

   s = BZALLOC( sizeof(DState) );

   if (s == NULL) return BZ_MEM_ERROR;

   s->strm                  = strm;

   strm->state              = s;

   s->state                 = BZ_X_MAGIC_1;

   s->bsLive                = 0;

   s->bsBuff                = 0;

   s->calculatedCombinedCRC = 0;

   strm->total_in_lo32      = 0;

   strm->total_in_hi32      = 0;

   strm->total_out_lo32     = 0;

   strm->total_out_hi32     = 0;

   s->smallDecompress       = (Bool)small;

   s->ll4                   = NULL;

   s->ll16                  = NULL;

   s->tt                    = NULL;

   s->currBlockNo           = 0;

   s->verbosity             = verbosity;

   return BZ_OK;

}

/*---------------------------------------------------*/

static

void unRLE_obuf_to_output_FAST ( DState* s )

{

   UChar k1;

   if (s->blockRandomised) {

      while (True) {

         /* try to finish existing run */

         while (True) {

            if (s->strm->avail_out == 0) return;

            if (s->state_out_len == 0) break;

            *( (UChar*)(s->strm->next_out) ) = s->state_out_ch;

            BZ_UPDATE_CRC ( s->calculatedBlockCRC, s->state_out_ch );

            s->state_out_len--;

            s->strm->next_out++;

            s->strm->avail_out--;

            s->strm->total_out_lo32++;

            if (s->strm->total_out_lo32 == 0) s->strm->total_out_hi32++;

         }

         /* can a new run be started? */

         if (s->nblock_used == s->save_nblock+1) return;

         s->state_out_len = 1;

         s->state_out_ch = s->k0;

         BZ_GET_FAST(k1); BZ_RAND_UPD_MASK; 

         k1 ^= BZ_RAND_MASK; s->nblock_used++;

         if (s->nblock_used == s->save_nblock+1) continue;

         if (k1 != s->k0) { s->k0 = k1; continue; };

         s->state_out_len = 2;

         BZ_GET_FAST(k1); BZ_RAND_UPD_MASK; 

         k1 ^= BZ_RAND_MASK; s->nblock_used++;

         if (s->nblock_used == s->save_nblock+1) continue;

         if (k1 != s->k0) { s->k0 = k1; continue; };

         s->state_out_len = 3;

         BZ_GET_FAST(k1); BZ_RAND_UPD_MASK; 

         k1 ^= BZ_RAND_MASK; s->nblock_used++;

         if (s->nblock_used == s->save_nblock+1) continue;

         if (k1 != s->k0) { s->k0 = k1; continue; };

         BZ_GET_FAST(k1); BZ_RAND_UPD_MASK; 

         k1 ^= BZ_RAND_MASK; s->nblock_used++;

         s->state_out_len = ((Int32)k1) + 4;

         BZ_GET_FAST(s->k0); BZ_RAND_UPD_MASK; 

         s->k0 ^= BZ_RAND_MASK; s->nblock_used++;

      }

   } else {

      /* restore */

      UInt32        c_calculatedBlockCRC = s->calculatedBlockCRC;

      UChar         c_state_out_ch       = s->state_out_ch;

      Int32         c_state_out_len      = s->state_out_len;

      Int32         c_nblock_used        = s->nblock_used;

      Int32         c_k0                 = s->k0;

      UInt32*       c_tt                 = s->tt;

      UInt32        c_tPos               = s->tPos;

      char*         cs_next_out          = s->strm->next_out;

      unsigned int  cs_avail_out         = s->strm->avail_out;

      /* end restore */

      UInt32       avail_out_INIT = cs_avail_out;

      Int32        s_save_nblockPP = s->save_nblock+1;

      unsigned int total_out_lo32_old;

      while (True) {

         /* try to finish existing run */

         if (c_state_out_len > 0) {

            while (True) {

               if (cs_avail_out == 0) goto return_notr;

               if (c_state_out_len == 1) break;

               *( (UChar*)(cs_next_out) ) = c_state_out_ch;

               BZ_UPDATE_CRC ( c_calculatedBlockCRC, c_state_out_ch );

               c_state_out_len--;

               cs_next_out++;

               cs_avail_out--;

            }

            s_state_out_len_eq_one:

            {

               if (cs_avail_out == 0) { 

                  c_state_out_len = 1; goto return_notr;

               };

               *( (UChar*)(cs_next_out) ) = c_state_out_ch;

               BZ_UPDATE_CRC ( c_calculatedBlockCRC, c_state_out_ch );

               cs_next_out++;

               cs_avail_out--;

            }

         }   

         /* can a new run be started? */

         if (c_nblock_used == s_save_nblockPP) {

            c_state_out_len = 0; goto return_notr;

         };   

         c_state_out_ch = c_k0;

         BZ_GET_FAST_C(k1); c_nblock_used++;

         if (k1 != c_k0) { 

            c_k0 = k1; goto s_state_out_len_eq_one; 

         };

         if (c_nblock_used == s_save_nblockPP) 

            goto s_state_out_len_eq_one;

         c_state_out_len = 2;

         BZ_GET_FAST_C(k1); c_nblock_used++;

         if (c_nblock_used == s_save_nblockPP) continue;

         if (k1 != c_k0) { c_k0 = k1; continue; };

         c_state_out_len = 3;

         BZ_GET_FAST_C(k1); c_nblock_used++;

         if (c_nblock_used == s_save_nblockPP) continue;

         if (k1 != c_k0) { c_k0 = k1; continue; };

         BZ_GET_FAST_C(k1); c_nblock_used++;

         c_state_out_len = ((Int32)k1) + 4;

         BZ_GET_FAST_C(c_k0); c_nblock_used++;

      }

      return_notr:

      total_out_lo32_old = s->strm->total_out_lo32;

      s->strm->total_out_lo32 += (avail_out_INIT - cs_avail_out);

      if (s->strm->total_out_lo32 < total_out_lo32_old)

         s->strm->total_out_hi32++;

      /* save */

      s->calculatedBlockCRC = c_calculatedBlockCRC;

      s->state_out_ch       = c_state_out_ch;

      s->state_out_len      = c_state_out_len;

      s->nblock_used        = c_nblock_used;

      s->k0                 = c_k0;

      s->tt                 = c_tt;

      s->tPos               = c_tPos;

      s->strm->next_out     = cs_next_out;

      s->strm->avail_out    = cs_avail_out;

      /* end save */

   }

}

/*---------------------------------------------------*/

__inline__ Int32 BZ2_indexIntoF ( Int32 indx, Int32 *cftab )

{

   Int32 nb, na, mid;

   nb = 0;

   na = 256;

   do {

      mid = (nb + na) >> 1;

      if (indx >= cftab[mid]) nb = mid; else na = mid;

   }

   while (na - nb != 1);

   return nb;

}

/*---------------------------------------------------*/

static

void unRLE_obuf_to_output_SMALL ( DState* s )

{

   UChar k1;

   if (s->blockRandomised) {

      while (True) {

         /* try to finish existing run */

         while (True) {

            if (s->strm->avail_out == 0) return;

            if (s->state_out_len == 0) break;

            *( (UChar*)(s->strm->next_out) ) = s->state_out_ch;

            BZ_UPDATE_CRC ( s->calculatedBlockCRC, s->state_out_ch );

            s->state_out_len--;

            s->strm->next_out++;

            s->strm->avail_out--;

            s->strm->total_out_lo32++;

            if (s->strm->total_out_lo32 == 0) s->strm->total_out_hi32++;

         }

         /* can a new run be started? */

         if (s->nblock_used == s->save_nblock+1) return;

         s->state_out_len = 1;

         s->state_out_ch = s->k0;

         BZ_GET_SMALL(k1); BZ_RAND_UPD_MASK; 

         k1 ^= BZ_RAND_MASK; s->nblock_used++;

         if (s->nblock_used == s->save_nblock+1) continue;

         if (k1 != s->k0) { s->k0 = k1; continue; };

         s->state_out_len = 2;

         BZ_GET_SMALL(k1); BZ_RAND_UPD_MASK; 

         k1 ^= BZ_RAND_MASK; s->nblock_used++;

         if (s->nblock_used == s->save_nblock+1) continue;

         if (k1 != s->k0) { s->k0 = k1; continue; };

         s->state_out_len = 3;

         BZ_GET_SMALL(k1); BZ_RAND_UPD_MASK; 

         k1 ^= BZ_RAND_MASK; s->nblock_used++;

         if (s->nblock_used == s->save_nblock+1) continue;

         if (k1 != s->k0) { s->k0 = k1; continue; };

         BZ_GET_SMALL(k1); BZ_RAND_UPD_MASK; 

         k1 ^= BZ_RAND_MASK; s->nblock_used++;

         s->state_out_len = ((Int32)k1) + 4;

         BZ_GET_SMALL(s->k0); BZ_RAND_UPD_MASK; 

         s->k0 ^= BZ_RAND_MASK; s->nblock_used++;

      }

   } else {

      while (True) {

         /* try to finish existing run */

         while (True) {

            if (s->strm->avail_out == 0) return;

            if (s->state_out_len == 0) break;

            *( (UChar*)(s->strm->next_out) ) = s->state_out_ch;

            BZ_UPDATE_CRC ( s->calculatedBlockCRC, s->state_out_ch );

            s->state_out_len--;

            s->strm->next_out++;

            s->strm->avail_out--;

            s->strm->total_out_lo32++;

            if (s->strm->total_out_lo32 == 0) s->strm->total_out_hi32++;

         }

         /* can a new run be started? */

         if (s->nblock_used == s->save_nblock+1) return;

         s->state_out_len = 1;

         s->state_out_ch = s->k0;

         BZ_GET_SMALL(k1); s->nblock_used++;

         if (s->nblock_used == s->save_nblock+1) continue;

         if (k1 != s->k0) { s->k0 = k1; continue; };

         s->state_out_len = 2;

         BZ_GET_SMALL(k1); s->nblock_used++;

         if (s->nblock_used == s->save_nblock+1) continue;

         if (k1 != s->k0) { s->k0 = k1; continue; };

         s->state_out_len = 3;

         BZ_GET_SMALL(k1); s->nblock_used++;

         if (s->nblock_used == s->save_nblock+1) continue;

         if (k1 != s->k0) { s->k0 = k1; continue; };

         BZ_GET_SMALL(k1); s->nblock_used++;

         s->state_out_len = ((Int32)k1) + 4;

         BZ_GET_SMALL(s->k0); s->nblock_used++;

      }

   }

}

/*---------------------------------------------------*/

int BZ_API(BZ2_bzDecompress) ( bz_stream *strm )

{

   DState* s;

   if (strm == NULL) return BZ_PARAM_ERROR;

   s = strm->state;

   if (s == NULL) return BZ_PARAM_ERROR;

   if (s->strm != strm) return BZ_PARAM_ERROR;

   while (True) {

      if (s->state == BZ_X_IDLE) return BZ_SEQUENCE_ERROR;

      if (s->state == BZ_X_OUTPUT) {

         if (s->smallDecompress)

            unRLE_obuf_to_output_SMALL ( s ); else

            unRLE_obuf_to_output_FAST  ( s );

         if (s->nblock_used == s->save_nblock+1 && s->state_out_len == 0) {

            BZ_FINALISE_CRC ( s->calculatedBlockCRC );

            if (s->verbosity >= 3) 

               VPrintf2 ( " {0x%x, 0x%x}", s->storedBlockCRC, 

                          s->calculatedBlockCRC );

            if (s->verbosity >= 2) VPrintf0 ( "]" );

            if (s->calculatedBlockCRC != s->storedBlockCRC)

               return BZ_DATA_ERROR;

            s->calculatedCombinedCRC 

               = (s->calculatedCombinedCRC << 1) | 

                    (s->calculatedCombinedCRC >> 31);

            s->calculatedCombinedCRC ^= s->calculatedBlockCRC;

            s->state = BZ_X_BLKHDR_1;

         } else {

            return BZ_OK;

         }

      }

      if (s->state >= BZ_X_MAGIC_1) {

         Int32 r = BZ2_decompress ( s );

         if (r == BZ_STREAM_END) {

            if (s->verbosity >= 3)

               VPrintf2 ( "\n    combined CRCs: stored = 0x%x, computed = 0x%x", 

                          s->storedCombinedCRC, s->calculatedCombinedCRC );

            if (s->calculatedCombinedCRC != s->storedCombinedCRC)

               return BZ_DATA_ERROR;

            return r;

         }

         if (s->state != BZ_X_OUTPUT) return r;

      }

   }

}

/*---------------------------------------------------*/

int BZ_API(BZ2_bzDecompressEnd)  ( bz_stream *strm )

{

   DState* s;

   if (strm == NULL) return BZ_PARAM_ERROR;

   s = strm->state;

   if (s == NULL) return BZ_PARAM_ERROR;

   if (s->strm != strm) return BZ_PARAM_ERROR;

   if (s->tt   != NULL) BZFREE(s->tt);

   if (s->ll16 != NULL) BZFREE(s->ll16);

   if (s->ll4  != NULL) BZFREE(s->ll4);

   BZFREE(strm->state);

   strm->state = NULL;

   return BZ_OK;

}