// Closed hash table

#include "Hash.h"

// creates a table to store up to n values with guaranteed load factor.
// vbits = # of bits per entry, ENTRIES CANNOT HAVE ZERO VALUE

Hash::Hash(ulong n, unsigned vbits, double factor)   
{ 
  //   hash H = malloc (sizeof(struct shash));
  //      int i,N;
  //      if (n == 0) return NULL;
  ulong N = (ulong)(n*factor); 
  if (N <= n) 
    N = n+1;
  this->size = (1lu << Tools::bits(N-1)) - 1;
  this->bits = vbits;
  //H->table = malloc ((((H->size+1)*vbits+W-1)/W)*sizeof(uint));
  table = new ulong[((size+1)*vbits+W-1)/W];
#ifdef INDEXREPORT
  printf ("     Also created hash table of %i bits\n",
	  (((size+1)*vbits+W-1)/W)*W);
#endif
  for (ulong i=0; i < (((size+1)*vbits+W-1)/W); i++) 
    table[i] = 0;
}

// frees the structure

Hash::~Hash ()

{ 
  delete [] table;
}

// inserts an entry, not prepared for overflow

void Hash::insertHash (ulong key, ulong value)
{ 
  ulong pos = (key*PRIME1) & size;
  //     if (bitget(table, pos*bits, bits) != 0)
  if (Tools::GetVariableField(table, bits, pos*bits) != 0)
    { 
      do pos = (pos + PRIME2) & size;
      while (Tools::GetVariableField(table, bits, pos*bits));
    }
  //      bitput(table, pos*bits, bits, value);
  Tools::SetVariableField(table, bits, pos*bits, value);
}

// looks for a key, returns first value (zero => no values)
// writes in pos a handle to get next values

unsigned Hash::searchHash (ulong key, ulong *h)

{ 
  *h = (key*PRIME1) & size;
  //      return bitget(H->table,*h*H->bits,H->bits);
  return Tools::GetVariableField(table, bits, *h*bits);
}

// gets following values using handle *pos, which is rewritten
// returns next value (zero => no more values)

unsigned Hash::nextHash (ulong *h)

{
  *h = (*h +PRIME2) & size;
  //      return bitget(table, *h*bits, bits);
  return Tools::GetVariableField(table, bits, *h*bits);
}