Hash_i_dh.c

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//       Ifpack: Object-Oriented Algebraic Preconditioner Package
//                 Copyright (2002) Sandia Corporation
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#include "Hash_i_dh.h"
#include "Parser_dh.h"
#include "Mem_dh.h"

#define DEFAULT_TABLE_SIZE 16

static void rehash_private (Hash_i_dh h);


/*--------------------------------------------------------------
 * hash functions (double hashing is used)
 *--------------------------------------------------------------*/
#define HASH_1(k,size,idxOut)    \
         {  *idxOut = k % size;  }

#define HASH_2(k,size,idxOut)      \
          {  \
            int r = k % (size-13); \
            r = (r % 2) ? r : r+1; \
            *idxOut = r;           \
          }


/*--------------------------------------------------------------
 * class structure
 *--------------------------------------------------------------*/
typedef struct _hash_i_node_private Hash_i_Record;

struct _hash_i_node_private
{
  int key;
  int mark;
  int data;
};


struct _hash_i_dh
{
  int size;         /* total slots in table */
  int count;            /* number of items inserted in table */
  int curMark;          /* used by Reset */
  Hash_i_Record *data;
};


/*--------------------------------------------------------------
 * class methods follow
 *--------------------------------------------------------------*/

#undef __FUNC__
#define __FUNC__ "Hash_i_dhCreate"
void
Hash_i_dhCreate (Hash_i_dh * h, int sizeIN)
{
  START_FUNC_DH int i, size;
  Hash_i_Record *tmp2;
  struct _hash_i_dh *tmp;

  size = DEFAULT_TABLE_SIZE;
  if (sizeIN == -1)
    {
      sizeIN = size = DEFAULT_TABLE_SIZE;
    }
  tmp = (struct _hash_i_dh *) MALLOC_DH (sizeof (struct _hash_i_dh));
  CHECK_V_ERROR;
  *h = tmp;
  tmp->size = 0;
  tmp->count = 0;
  tmp->curMark = 0;
  tmp->data = NULL;

  /*
     determine initial hash table size.  If this is too small,
     it will be dynamically enlarged as needed by Hash_i_dhInsert()
     See "double hashing," p. 255, "Algorithms," Cormen, et. al.
   */
  while (size < sizeIN)
    size *= 2;          /* want table size to be a power of 2: */
  /* rule-of-thumb: ensure there's at least 10% padding */
  if ((size - sizeIN) < (.1 * size))
    {
      size *= 2.0;
    }
  tmp->size = size;


  /* allocate and zero the hash table */
  tmp2 = tmp->data =
    (Hash_i_Record *) MALLOC_DH (size * sizeof (Hash_i_Record));
  CHECK_V_ERROR;
  for (i = 0; i < size; ++i)
    {
      tmp2[i].key = -1;
      tmp2[i].mark = -1;
      /* "tmp2[i].data" needn't be initialized */
    }

END_FUNC_DH}


#undef __FUNC__
#define __FUNC__ "Hash_i_dhDestroy"
void
Hash_i_dhDestroy (Hash_i_dh h)
{
  START_FUNC_DH if (h->data != NULL)
    {
      FREE_DH (h->data);
      CHECK_V_ERROR;
    }
  FREE_DH (h);
  CHECK_V_ERROR;
END_FUNC_DH}

#undef __FUNC__
#define __FUNC__ "Hash_i_dhReset"
void
Hash_i_dhReset (Hash_i_dh h)
{
  START_FUNC_DH h->count = 0;
  h->curMark += 1;
END_FUNC_DH}


#undef __FUNC__
#define __FUNC__ "Hash_i_dhLookup"
int
Hash_i_dhLookup (Hash_i_dh h, int key)
{
  START_FUNC_DH int idx, inc, i, start;
  int curMark = h->curMark;
  int size = h->size;
  int retval = -1;
  Hash_i_Record *data = h->data;

  HASH_1 (key, size, &start) HASH_2 (key, size, &inc)
/*printf("Hash_i_dhLookup:: key: %i  tableSize: %i start: %i  inc: %i\n", key, size, start, inc);
*/
    for (i = 0; i < size; ++i)
    {
      idx = (start + i * inc) % size;

/* printf("   idx= %i\n", idx); */

      if (data[idx].mark != curMark)
    {
      break;        /* key wasn't found */
    }
      else
    {
      if (data[idx].key == key)
        {
          retval = data[idx].data;
          break;
        }
    }
    }
END_FUNC_VAL (retval)}


#undef __FUNC__
#define __FUNC__ "Hash_i_dhInsert"
void
Hash_i_dhInsert (Hash_i_dh h, int key, int dataIN)
{
  START_FUNC_DH int i, idx, inc, start, size;
  int curMark = h->curMark;
  Hash_i_Record *data;
  bool success = false;

  if (dataIN < 0)
    {
      sprintf (msgBuf_dh, "data = %i must be >= 0", dataIN);
      SET_V_ERROR (msgBuf_dh);
    }

  /* enlarge table if necessary */
  if (h->count >= 0.9 * h->size)
    {
      rehash_private (h);
      CHECK_V_ERROR;
    }

  size = h->size;
  data = h->data;
  h->count += 1;        /* for this insertion */

  HASH_1 (key, size, &start) HASH_2 (key, size, &inc)
/*printf("Hash_i_dhInsert::  tableSize= %i  start= %i  inc= %i\n", size, start, inc);
*/
    for (i = 0; i < size; ++i)
    {
      idx = (start + i * inc) % size;

/* printf("   idx= %i\n", idx);
*/

      /* check for previous insertion */
      if (data[idx].mark == curMark && data[idx].key == key)
    {
      sprintf (msgBuf_dh, "key,data= <%i, %i> already inserted", key,
           dataIN);
      SET_V_ERROR (msgBuf_dh);
    }

      if (data[idx].mark < curMark)
    {
      data[idx].key = key;
      data[idx].mark = curMark;
      data[idx].data = dataIN;
      success = true;
      break;
    }
    }

  if (!success)
    {               /* should be impossible to be here, I think . . . */
      sprintf (msgBuf_dh, "Failed to insert key= %i, data= %i", key, dataIN);
    }
END_FUNC_DH}


#undef __FUNC__
#define __FUNC__ "rehash_private"
void
rehash_private (Hash_i_dh h)
{
  START_FUNC_DH
    int i,
    old_size = h->size, new_size = old_size * 2, oldCurMark = h->curMark;
  Hash_i_Record *oldData = h->data, *newData;

  sprintf (msgBuf_dh, "rehashing; old_size= %i, new_size= %i", old_size,
       new_size);
  SET_INFO (msgBuf_dh);

  /* allocate new data table, and install it in the Hash_i_dh object;
     essentially, we reinitialize the hash object.
   */
  newData = (Hash_i_Record *) MALLOC_DH (new_size * sizeof (Hash_i_Record));
  CHECK_V_ERROR;
  for (i = 0; i < new_size; ++i)
    {
      newData[i].key = -1;
      newData[i].mark = -1;
    }
  h->size = new_size;
  h->data = newData;
  h->count = 0;
  h->curMark = 0;

  for (i = h->count; i < new_size; ++i)
    {
      newData[i].key = -1;
      newData[i].mark = -1;
    }

  /* insert <key, data> pairs from old table to new table;
     wouldn't have been called) it's simplest to sweep through
     the old table.
   */
  for (i = 0; i < old_size; ++i)
    {
      if (oldData[i].mark == oldCurMark)
    {
      Hash_i_dhInsert (h, oldData[i].key, oldData[i].data);
      CHECK_V_ERROR;
    }
    }

  FREE_DH (oldData);
  CHECK_V_ERROR;
END_FUNC_DH}