// 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"

static int match(fdibuf& in, const mystring& key)

{

  unsigned len = key.length();

  const char* keyptr = key.c_str();

  while (len > 0) {

    char buf[32];

    unsigned n = sizeof buf;

    if(n > len) n = len;

    if(!in.read(buf, n)) return -1;

    for(unsigned i = 0;i < n;++i)

      if(buf[i] != keyptr[i]) return 0;

    keyptr += n;

    len -= n;

  }

  return 1;

}

int cdb_reader::seek(const mystring& key, uint32& dlen)

{

  if(failed)

    return -1;

  uint32 h = hash(key);

  uint32 pos = 8 * (h & 255);

  uint32 poshash = unpack(header+pos); 

  uint32 lenhash = unpack(header+pos+4);

  if(!lenhash) return 0;

  uint32 h2 = (h >> 8) % lenhash;

  for (uint32 loop = 0; loop < lenhash; ++loop) {

    if(!in.seek(poshash+8*h2)) return -1;

    unsigned char packbuf[8];

    if(!in.read(packbuf, 8)) return -1;

    uint32 poskd = unpack(packbuf + 4);

    if(!poskd) return 0;

    if(unpack(packbuf) == h) {

      if(!in.seek(poskd)) return -1;

      if(!in.read(packbuf, 8)) return -1;

      if(unpack(packbuf) == key.length())

	switch(match(in, key)) {

	case -1:

	  return -1;

	case 1:

	  dlen = unpack(packbuf + 4);

	  return 1;

	}

    }

    if(++h2 == lenhash) h2 = 0;

  }

  return 0;

}

datum* cdb_reader::get(const mystring& key)

{

  if(failed)

    return 0;

  uint32 len;

  switch(seek(key, len)) {

  case -1: return 0;

  case 0:  return 0;

  }

  // Big assume: data is relatively small (will fit on stack)

  char buf[len];

  datum* d = !in.read(buf, len) ? 0 : new datum(key, mystring(buf, len));

  return d;

}