/********************************************************************************
*                                                                               *
*                      B Z F i l e S t r e a m   C l a s s e s                  *
*                                                                               *
*********************************************************************************
* Copyright (C) 1999,2025 by Lyle Johnson. All Rights Reserved.                 *
*********************************************************************************
* This library is free software; you can redistribute it and/or modify          *
* it under the terms of the GNU Lesser General Public License as published by   *
* the Free Software Foundation; either version 3 of the License, or             *
* (at your option) any later version.                                           *
*                                                                               *
* This library is distributed in the hope that it will be useful,               *
* but WITHOUT ANY WARRANTY; without even the implied warranty of                *
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the                 *
* GNU Lesser General Public License for more details.                           *
*                                                                               *
* You should have received a copy of the GNU Lesser General Public License      *
* along with this program.  If not, see <http://www.gnu.org/licenses/>          *
********************************************************************************/
#include "xincs.h"
#include "fxver.h"
#include "fxdefs.h"
#include "fxmath.h"
#include "FXElement.h"
#include "FXHash.h"
#include "FXStream.h"
#include "FXString.h"
#include "FXFile.h"
#include "FXBZFileStream.h"

#ifdef HAVE_BZ2LIB_H
#include <bzlib.h>

/*
  Notes:
  - Very basic compressed file I/O only.
  - Updated for new stream classes 2003/07/08.
  - Updated for use with FXFile 2005/09/03.
*/


#define BLOCKSIZE100K 1         // Block size x 100,000 bytes
#define VERBOSITY     0         // For tracing in bzip library
#define WORKFACTOR    0         // See bzip2 documentation
#define BUFFERSIZE    8192      // Size of the buffer

using namespace FX;

/*******************************************************************************/

namespace FX {


// Used during compression
struct BZBlock {
  bz_stream stream;
  char      buffer[BUFFERSIZE];
  };


// Create BZIP2 file stream
FXBZFileStream::FXBZFileStream(const FXObject* cont):FXFileStream(cont),bz(nullptr),ac(0){
  }


// Create and open BZIP2 file stream
FXBZFileStream::FXBZFileStream(const FXString& filename,FXStreamDirection save_or_load,FXuval size):bz(nullptr),ac(0){
  open(filename,save_or_load,size);
  }


// Save to a file
FXuval FXBZFileStream::writeBuffer(FXuval){
  FXival m,n; int bzerror;
  if(dir!=FXStreamSave){fxerror("FXBZFileStream::writeBuffer: wrong stream direction.\n");}
  FXASSERT(begptr<=rdptr);
  FXASSERT(rdptr<=wrptr);
  FXASSERT(wrptr<=endptr);
  while(rdptr<wrptr || ac==BZ_FINISH || ac==BZ_FLUSH){
    bz->stream.next_in=(char*)rdptr;
    bz->stream.avail_in=wrptr-rdptr;
    bz->stream.next_out=bz->buffer;
    bz->stream.avail_out=BUFFERSIZE;
    bzerror=BZ2_bzCompress(&bz->stream,ac);
    if(bzerror<BZ_OK) break;                            // Error occurred
    m=bz->stream.next_out-bz->buffer;
    n=file.writeBlock(bz->buffer,m);
    if(n<m) break;                                      // Failed to write data
    rdptr=(FXuchar*)bz->stream.next_in;
    if(bzerror==BZ_STREAM_END) break;                   // Finished all data
    if(bzerror==BZ_RUN_OK && ac==BZ_FLUSH) break;       // Flushed all data
    }
  if(rdptr<wrptr){memmove(begptr,rdptr,wrptr-rdptr);}
  wrptr=begptr+(wrptr-rdptr);
  rdptr=begptr;
  return endptr-wrptr;
  }


// Load from file
FXuval FXBZFileStream::readBuffer(FXuval){
  FXival n; int bzerror;
  if(dir!=FXStreamLoad){fxerror("FXBZFileStream::readBuffer: wrong stream direction.\n");}
  FXASSERT(begptr<=rdptr);
  FXASSERT(rdptr<=wrptr);
  FXASSERT(wrptr<=endptr);
  if(rdptr<wrptr){memmove(begptr,rdptr,wrptr-rdptr);}
  wrptr=begptr+(wrptr-rdptr);
  rdptr=begptr;
  while(wrptr<endptr){
    if(bz->stream.avail_in<=0){                         // Read more input
      n=file.readBlock(bz->buffer,BUFFERSIZE);
      if(n<=0) break;
      bz->stream.next_in=bz->buffer;
      bz->stream.avail_in=n;
      }
    bz->stream.next_out=(char*)wrptr;
    bz->stream.avail_out=endptr-wrptr;
    bzerror=BZ2_bzDecompress(&bz->stream);
    if(bzerror<BZ_OK) break;                            // Error occurred
    wrptr=(FXuchar*)bz->stream.next_out;
    if(bzerror==BZ_STREAM_END) break;                   // Hit end of file
    }
  return wrptr-rdptr;
  }


// Try open file stream
FXbool FXBZFileStream::open(const FXString& filename,FXStreamDirection save_or_load,FXuval size){
  if(FXFileStream::open(filename,save_or_load,size)){
    if(callocElms(bz,1)){
      int bzerror;
      bz->stream.next_in=nullptr;
      bz->stream.avail_in=0;
      bz->stream.next_out=nullptr;
      bz->stream.avail_out=0;
      ac=BZ_RUN;
      if(save_or_load==FXStreamLoad){
        bzerror=BZ2_bzDecompressInit(&bz->stream,VERBOSITY,0);
        if(bzerror==BZ_OK) return true;
        code=FXStreamNoRead;
        }
      else{
        bzerror=BZ2_bzCompressInit(&bz->stream,BLOCKSIZE100K,VERBOSITY,WORKFACTOR);
        if(bzerror==BZ_OK) return true;
        code=FXStreamNoWrite;
        }
      freeElms(bz);
      }
    FXFileStream::close();
    }
  return false;
  }


// Flush buffer
FXbool FXBZFileStream::flush(){
  FXbool result;
  int action=ac;
  if(ac!=BZ_FINISH) ac=BZ_FLUSH;
  result=FXStream::flush();
  ac=action;
  return result;
  }


// Close file stream
FXbool FXBZFileStream::close(){
  if(dir){
    if(dir==FXStreamLoad){
      FXFileStream::close();
      BZ2_bzDecompressEnd(&bz->stream);
      }
    else{
      ac=BZ_FINISH;
      FXFileStream::close();
      BZ2_bzCompressEnd(&bz->stream);
      }
    freeElms(bz);
    return true;
    }
  return false;
  }


// Destructor
FXBZFileStream::~FXBZFileStream(){
  close();
  }

}

#endif
