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

 * $Id$

 *

 * Project:  MapServer

 * Purpose:  Implement hashTableObj class.

 * Author:   Sean Gillies, sgillies@frii.com

 *

 ******************************************************************************

 * Copyright (c) 1996-2005 Regents of the University of Minnesota.

 *

 * Permission is hereby granted, free of charge, to any person obtaining a

 * copy of this software and associated documentation files (the "Software"),

 * to deal in the Software without restriction, including without limitation

 * the rights to use, copy, modify, merge, publish, distribute, sublicense,

 * and/or sell copies of the Software, and to permit persons to whom the

 * Software is furnished to do so, subject to the following conditions:

 *

 * The above copyright notice and this permission notice shall be included in

 * all copies of this Software or works derived from this Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS

 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL

 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING

 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER

 * DEALINGS IN THE SOFTWARE.

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

#include <ctype.h>

#include "mapserver.h"

#include "maphash.h"

static unsigned hash(const char *key) {

  unsigned hashval;

  for (hashval = 0; *key != '\0'; key++)

    hashval = tolower(*key) + 31 * hashval;

  return (hashval % MS_HASHSIZE);

}

hashTableObj *msCreateHashTable() {

  int i;

  hashTableObj *table;

  table = (hashTableObj *)msSmallMalloc(sizeof(hashTableObj));

  table->items =

      (struct hashObj **)msSmallMalloc(sizeof(struct hashObj *) * MS_HASHSIZE);

  for (i = 0; i < MS_HASHSIZE; i++)

    table->items[i] = NULL;

  table->numitems = 0;

  return table;

}

int initHashTable(hashTableObj *table) {

  int i;

  table->items =

      (struct hashObj **)malloc(sizeof(struct hashObj *) * MS_HASHSIZE);

  MS_CHECK_ALLOC(table->items, sizeof(struct hashObj *) * MS_HASHSIZE,

                 MS_FAILURE);

  for (i = 0; i < MS_HASHSIZE; i++)

    table->items[i] = NULL;

  table->numitems = 0;

  return MS_SUCCESS;

}

void msFreeHashTable(hashTableObj *table) {

  if (table != NULL) {

    msFreeHashItems(table);

    free(table);

  }

}

int msHashIsEmpty(const hashTableObj *table) {

  if (table->numitems == 0)

    return MS_TRUE;

  else

    return MS_FALSE;

}

void msFreeHashItems(hashTableObj *table) {

  int i;

  struct hashObj *tp = NULL;

  struct hashObj *prev_tp = NULL;

  if (table) {

    if (table->items) {

      for (i = 0; i < MS_HASHSIZE; i++) {

        if (table->items[i] != NULL) {

          for (tp = table->items[i]; tp != NULL;

               prev_tp = tp, tp = tp->next, free(prev_tp)) {

            msFree(tp->key);

            msFree(tp->data);

          }

        }

      }

      free(table->items);

      table->items = NULL;

    } else {

      msSetError(MS_HASHERR, "No items allocated.", "msFreeHashItems()");

    }

  } else {

    msSetError(MS_HASHERR, "Can't free NULL table", "msFreeHashItems()");

  }

}

struct hashObj *msInsertHashTable(hashTableObj *table, const char *key,

                                  const char *value) {

  struct hashObj *tp;

  unsigned hashval;

  if (!table || !key || !value) {

    msSetError(MS_HASHERR, "Invalid hash table or key", "msInsertHashTable");

    return NULL;

  }

  for (tp = table->items[hash(key)]; tp != NULL; tp = tp->next)

    if (strcasecmp(key, tp->key) == 0)

      break;

  if (tp == NULL) { /* not found */

    tp = (struct hashObj *)malloc(sizeof(*tp));

    MS_CHECK_ALLOC(tp, sizeof(*tp), NULL);

    tp->key = msStrdup(key);

    hashval = hash(key);

    tp->next = table->items[hashval];

    table->items[hashval] = tp;

    table->numitems++;

  } else {

    free(tp->data);

  }

  if ((tp->data = msStrdup(value)) == NULL)

    return NULL;

  return tp;

}

const char *msLookupHashTable(const hashTableObj *table, const char *key) {

  struct hashObj *tp;

  if (!table || !key) {

    return (NULL);

  }

  for (tp = table->items[hash(key)]; tp != NULL; tp = tp->next)

    if (strcasecmp(key, tp->key) == 0)

      return (tp->data);

  return NULL;

}

int msRemoveHashTable(hashTableObj *table, const char *key) {

  struct hashObj *tp;

  struct hashObj *prev_tp = NULL;

  int status = MS_FAILURE;

  if (!table || !key) {

    msSetError(MS_HASHERR, "No hash table", "msRemoveHashTable");

    return MS_FAILURE;

  }

  tp = table->items[hash(key)];

  if (!tp) {

    msSetError(MS_HASHERR, "No such hash entry", "msRemoveHashTable");

    return MS_FAILURE;

  }

  prev_tp = NULL;

  while (tp != NULL) {

    if (strcasecmp(key, tp->key) == 0) {

      status = MS_SUCCESS;

      if (prev_tp) {

        prev_tp->next = tp->next;

        msFree(tp->key);

        msFree(tp->data);

        free(tp);

        break;

      } else {

        table->items[hash(key)] = tp->next;

        msFree(tp->key);

        msFree(tp->data);

        free(tp);

        break;

      }

    }

    prev_tp = tp;

    tp = tp->next;

  }

  if (status == MS_SUCCESS)

    table->numitems--;

  return status;

}

const char *msFirstKeyFromHashTable(const hashTableObj *table) {

  int hash_index;

  if (!table) {

    msSetError(MS_HASHERR, "No hash table", "msFirstKeyFromHashTable");

    return NULL;

  }

  for (hash_index = 0; hash_index < MS_HASHSIZE; hash_index++) {

    if (table->items[hash_index] != NULL)

      return table->items[hash_index]->key;

  }

  return NULL;

}

const char *msNextKeyFromHashTable(const hashTableObj *table,

                                   const char *lastKey) {

  int hash_index;

  struct hashObj *link;

  if (!table) {

    msSetError(MS_HASHERR, "No hash table", "msNextKeyFromHashTable");

    return NULL;

  }

  if (lastKey == NULL)

    return msFirstKeyFromHashTable(table);

  hash_index = hash(lastKey);

  for (link = table->items[hash_index];

       link != NULL && strcasecmp(lastKey, link->key) != 0; link = link->next) {

  }

  if (link != NULL && link->next != NULL)

    return link->next->key;

  while (++hash_index < MS_HASHSIZE) {

    if (table->items[hash_index] != NULL)

      return table->items[hash_index]->key;

  }

  return NULL;

}