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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"

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

/*--- Compression stuff                           ---*/

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

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

static

void prepare_new_block ( EState* s )

{

   Int32 i;

   s->nblock = 0;

   s->numZ = 0;

   s->state_out_pos = 0;

   BZ_INITIALISE_CRC ( s->blockCRC );

   for (i = 0; i < 256; i++) s->inUse[i] = False;

   s->blockNo++;

}

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

static

void init_RL ( EState* s )

{

   s->state_in_ch  = 256;

   s->state_in_len = 0;

}

static

Bool isempty_RL ( EState* s )

{

   if (s->state_in_ch < 256 && s->state_in_len > 0)

      return False; else

      return True;

}

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

int BZ_API(BZ2_bzCompressInit) 

                    ( bz_stream* strm, 

                     int        blockSize100k,

                     int        verbosity,

                     int        workFactor )

{

   Int32   n;

   EState* s;

   if (!bz_config_ok()) return BZ_CONFIG_ERROR;

   if (strm == NULL || 

       blockSize100k < 1 || blockSize100k > 9 ||

       workFactor < 0 || workFactor > 250)

     return BZ_PARAM_ERROR;

   if (workFactor == 0) workFactor = 30;

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

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

   s = BZALLOC( sizeof(EState) );

   if (s == NULL) return BZ_MEM_ERROR;

   s->strm = strm;

   s->arr1 = NULL;

   s->arr2 = NULL;

   s->ftab = NULL;

   n       = 100000 * blockSize100k;

   s->arr1 = BZALLOC( n                  * sizeof(UInt32) );

   s->arr2 = BZALLOC( (n+BZ_N_OVERSHOOT) * sizeof(UInt32) );

   s->ftab = BZALLOC( 65537              * sizeof(UInt32) );

   if (s->arr1 == NULL || s->arr2 == NULL || s->ftab == NULL) {

      if (s->arr1 != NULL) BZFREE(s->arr1);

      if (s->arr2 != NULL) BZFREE(s->arr2);

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

      if (s       != NULL) BZFREE(s);

      return BZ_MEM_ERROR;

   }

   s->blockNo           = 0;

   s->state             = BZ_S_INPUT;

   s->mode              = BZ_M_RUNNING;

   s->combinedCRC       = 0;

   s->blockSize100k     = blockSize100k;

   s->nblockMAX         = 100000 * blockSize100k - 19;

   s->verbosity         = verbosity;

   s->workFactor        = workFactor;

   s->block             = (UChar*)s->arr2;

   s->mtfv              = (UInt16*)s->arr1;

   s->zbits             = NULL;

   s->ptr               = (UInt32*)s->arr1;

   strm->state          = s;

   strm->total_in_lo32  = 0;

   strm->total_in_hi32  = 0;

   strm->total_out_lo32 = 0;

   strm->total_out_hi32 = 0;

   init_RL ( s );

   prepare_new_block ( s );

   return BZ_OK;

}

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

static

void add_pair_to_block ( EState* s )

{

   Int32 i;

   UChar ch = (UChar)(s->state_in_ch);

   for (i = 0; i < s->state_in_len; i++) {

      BZ_UPDATE_CRC( s->blockCRC, ch );

   }

   s->inUse[s->state_in_ch] = True;

   switch (s->state_in_len) {

      case 1:

         s->block[s->nblock] = (UChar)ch; s->nblock++;

         break;

      case 2:

         s->block[s->nblock] = (UChar)ch; s->nblock++;

         s->block[s->nblock] = (UChar)ch; s->nblock++;

         break;

      case 3:

         s->block[s->nblock] = (UChar)ch; s->nblock++;

         s->block[s->nblock] = (UChar)ch; s->nblock++;

         s->block[s->nblock] = (UChar)ch; s->nblock++;

         break;

      default:

         s->inUse[s->state_in_len-4] = True;

         s->block[s->nblock] = (UChar)ch; s->nblock++;

         s->block[s->nblock] = (UChar)ch; s->nblock++;

         s->block[s->nblock] = (UChar)ch; s->nblock++;

         s->block[s->nblock] = (UChar)ch; s->nblock++;

         s->block[s->nblock] = ((UChar)(s->state_in_len-4));

         s->nblock++;

         break;

   }

}

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

static

void flush_RL ( EState* s )

{

   if (s->state_in_ch < 256) add_pair_to_block ( s );

   init_RL ( s );

}

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

#define ADD_CHAR_TO_BLOCK(zs,zchh0)               \

{                                                 \

   UInt32 zchh = (UInt32)(zchh0);                 \

   /*-- fast track the common case --*/           \

   if (zchh != zs->state_in_ch &&                 \

       zs->state_in_len == 1) {                   \

      UChar ch = (UChar)(zs->state_in_ch);        \

      BZ_UPDATE_CRC( zs->blockCRC, ch );          \

      zs->inUse[zs->state_in_ch] = True;          \

      zs->block[zs->nblock] = (UChar)ch;          \

      zs->nblock++;                               \

      zs->state_in_ch = zchh;                     \

   }                                              \

   else                                           \

   /*-- general, uncommon cases --*/              \

   if (zchh != zs->state_in_ch ||                 \

      zs->state_in_len == 255) {                  \

      if (zs->state_in_ch < 256)                  \

         add_pair_to_block ( zs );                \

      zs->state_in_ch = zchh;                     \

      zs->state_in_len = 1;                       \

   } else {                                       \

      zs->state_in_len++;                         \

   }                                              \

}

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

static

Bool copy_input_until_stop ( EState* s )

{

   Bool progress_in = False;

   if (s->mode == BZ_M_RUNNING) {

      /*-- fast track the common case --*/

      while (True) {

         /*-- block full? --*/

         if (s->nblock >= s->nblockMAX) break;

         /*-- no input? --*/

         if (s->strm->avail_in == 0) break;

         progress_in = True;

         ADD_CHAR_TO_BLOCK ( s, (UInt32)(*((UChar*)(s->strm->next_in))) ); 

         s->strm->next_in++;

         s->strm->avail_in--;

         s->strm->total_in_lo32++;

         if (s->strm->total_in_lo32 == 0) s->strm->total_in_hi32++;

      }

   } else {

      /*-- general, uncommon case --*/

      while (True) {

         /*-- block full? --*/

         if (s->nblock >= s->nblockMAX) break;

         /*-- no input? --*/

         if (s->strm->avail_in == 0) break;

         /*-- flush/finish end? --*/

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

         progress_in = True;

         ADD_CHAR_TO_BLOCK ( s, (UInt32)(*((UChar*)(s->strm->next_in))) ); 

         s->strm->next_in++;

         s->strm->avail_in--;

         s->strm->total_in_lo32++;

         if (s->strm->total_in_lo32 == 0) s->strm->total_in_hi32++;

         s->avail_in_expect--;

      }

   }

   return progress_in;

}

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

static

Bool copy_output_until_stop ( EState* s )

{

   Bool progress_out = False;

   while (True) {

      /*-- no output space? --*/

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

      /*-- block done? --*/

      if (s->state_out_pos >= s->numZ) break;

      progress_out = True;

      *(s->strm->next_out) = s->zbits[s->state_out_pos];

      s->state_out_pos++;

      s->strm->avail_out--;

      s->strm->next_out++;

      s->strm->total_out_lo32++;

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

   }

   return progress_out;

}

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

static

Bool handle_compress ( bz_stream* strm )

{

   Bool progress_in  = False;

   Bool progress_out = False;

   EState* s = strm->state;

   while (True) {

      if (s->state == BZ_S_OUTPUT) {

         progress_out |= copy_output_until_stop ( s );

         if (s->state_out_pos < s->numZ) break;

         if (s->mode == BZ_M_FINISHING && 

             s->avail_in_expect == 0 &&

             isempty_RL(s)) break;

         prepare_new_block ( s );

         s->state = BZ_S_INPUT;

         if (s->mode == BZ_M_FLUSHING && 

             s->avail_in_expect == 0 &&

             isempty_RL(s)) break;

      }

      if (s->state == BZ_S_INPUT) {

         progress_in |= copy_input_until_stop ( s );

         if (s->mode != BZ_M_RUNNING && s->avail_in_expect == 0) {

            flush_RL ( s );

            BZ2_compressBlock ( s, (Bool)(s->mode == BZ_M_FINISHING) );

            s->state = BZ_S_OUTPUT;

         }

         else

         if (s->nblock >= s->nblockMAX) {

            BZ2_compressBlock ( s, False );

            s->state = BZ_S_OUTPUT;

         }

         else

         if (s->strm->avail_in == 0) {

            break;

         }

      }

   }

   return progress_in || progress_out;

}

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

int BZ_API(BZ2_bzCompress) ( bz_stream *strm, int action )

{

   Bool progress;

   EState* 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;

   preswitch:

   switch (s->mode) {

      case BZ_M_IDLE:

         return BZ_SEQUENCE_ERROR;

      case BZ_M_RUNNING:

         if (action == BZ_RUN) {

            progress = handle_compress ( strm );

            return progress ? BZ_RUN_OK : BZ_PARAM_ERROR;

         } 

         else

	 if (action == BZ_FLUSH) {

            s->avail_in_expect = strm->avail_in;

            s->mode = BZ_M_FLUSHING;

            goto preswitch;

         }

         else

         if (action == BZ_FINISH) {

            s->avail_in_expect = strm->avail_in;

            s->mode = BZ_M_FINISHING;

            goto preswitch;

         }

         else 

            return BZ_PARAM_ERROR;

      case BZ_M_FLUSHING:

         if (action != BZ_FLUSH) return BZ_SEQUENCE_ERROR;

         if (s->avail_in_expect != s->strm->avail_in) 

            return BZ_SEQUENCE_ERROR;

         progress = handle_compress ( strm );

         if (!progress) return BZ_SEQUENCE_ERROR;	//rsc added

         if (s->avail_in_expect > 0 || !isempty_RL(s) ||

             s->state_out_pos < s->numZ) return BZ_FLUSH_OK;

         s->mode = BZ_M_RUNNING;

         return BZ_RUN_OK;

      case BZ_M_FINISHING:

         if (action != BZ_FINISH) return BZ_SEQUENCE_ERROR;

         if (s->avail_in_expect != s->strm->avail_in) 

            return BZ_SEQUENCE_ERROR;

         progress = handle_compress ( strm );

         if (!progress) return BZ_SEQUENCE_ERROR;

         if (s->avail_in_expect > 0 || !isempty_RL(s) ||

             s->state_out_pos < s->numZ) return BZ_FINISH_OK;

         s->mode = BZ_M_IDLE;

         return BZ_STREAM_END;

   }

   return BZ_OK; /*--not reached--*/

}

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

int BZ_API(BZ2_bzCompressEnd)  ( bz_stream *strm )

{

   EState* 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->arr1 != NULL) BZFREE(s->arr1);

   if (s->arr2 != NULL) BZFREE(s->arr2);

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

   BZFREE(strm->state);

   strm->state = NULL;   

   return BZ_OK;

}