// Copyright (C) 1999,2000 Bruce Guenter <bruceg@em.ca>

//

// This program is free software; you can redistribute it and/or modify

// it under the terms of the GNU General Public License as published by

// the Free Software Foundation; either version 2 of the License, or

// (at your option) any later version.

//

// This program 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 General Public License for more details.

//

// You should have received a copy of the GNU General Public License

// along with this program; if not, write to the Free Software

// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

#include "cdb++.h"

#include "internal.h"

#define FAIL do{ abort(); return 0; }while(0)

inline uint32 max(uint32 a, uint32 b)

{

  return a > b ? a : b;

}

cdb_reader::cdb_reader(const mystring& filename)

  : in(filename.c_str()),

    failed(!in),

    eof(false)

{

  firstrec();

}

cdb_reader::~cdb_reader()

{

}

void cdb_reader::abort()

{

  failed = true;

  in.close();

}

bool cdb_reader::firstrec()

{

  if(failed) return false;

  if(!in.seek(0) || !in.read(header, 2048)) {

    abort();

    return false;

  }

  eof = false;

  eod = unpack(header);

  pos = 2048;

  return true;

}

datum* cdb_reader::nextrec()

{

  if(eof) return 0;

  if(pos >= eod) {

    eof = true;

    return 0;

  }

  if(failed || eod-pos < 8 || !in.seek(pos)) FAIL;

  pos += 8;

  unsigned char buf[8];

  if(!in.read(buf, 8)) FAIL;

  uint32 klen = unpack(buf);

  uint32 dlen = unpack(buf+4);

  if (eod - pos < klen) FAIL;

  pos += klen;

  if (eod - pos < dlen) FAIL;

  pos += dlen;

  char tmp[max(klen, dlen)];

  if(!in.read(tmp, klen)) FAIL;

  mystring key(tmp, klen);

  if(!in.read(tmp, dlen)) FAIL;

  mystring data(tmp, dlen);

  return new datum(key, data);

}