/* -*- mode: c; indent-tabs-mode: nil; -*-
 * $Id$
 *
 * util -- Some simple utility routines so we don't need GLib
 * Copyright (c) 2002, Bill Janssen
 * 
 * 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.
 *
 */

#if !defined(WIN32)
#include <unistd.h>     /* for lseek, etc. */
#else
#include <io.h>
#endif
#include <stdlib.h>
#include <sys/types.h>
#include <stdarg.h>     /* for _plkr_message */
#include <stdio.h>      /* for stderr */
#include <sys/stat.h>   /* for fstat() */
#include <string.h>    /* for strndup() */
#include <errno.h>      /* for errno */
#include <fcntl.h>      /* for O_RDONLY */
#include <assert.h>     /* for assert() */

#include <zlib.h>


#include "unpluck.h"
#include "unpluckint.h"

/***********************************************************************/
/***********************************************************************/
/*****                                                             *****/
/*****                       Messages                              *****/
/*****                                                             *****/
/***********************************************************************/
/***********************************************************************/

static int ShowMessages = 0;

void _plkr_message (const char *formatSpec, ...)
{
  va_list ap;
  va_start (ap, formatSpec);

  if (ShowMessages) {
    (void) vfprintf (stderr, formatSpec, ap);
    fprintf(stderr, "\n");
  }

  va_end(ap);
}

int plkr_ShowMessages (int val)
{
  int oldval = ShowMessages;
  ShowMessages = val;
  return oldval;
}

/***********************************************************************/
/***********************************************************************/
/*****                                                             *****/
/*****                   String Utilities                          *****/
/*****                                                             *****/
/***********************************************************************/
/***********************************************************************/

char *_plkr_strndup (char *str, int len)
{
  char *dup;
  dup = (char *) malloc(len + 1);
  strncpy(dup, str, len);
  dup[len] = 0;
  return dup;
}

/***********************************************************************/
/***********************************************************************/
/*****                                                             *****/
/*****  Simple hash table maps string keys to void * values        *****/
/*****                                                             *****/
/***********************************************************************/
/***********************************************************************/

typedef struct {
  char *        he_key;
  void *        he_data;
} HashEntry;

typedef struct {
  int           hs_count;
  int           hs_allocated;
  HashEntry *   hs_entries;
} HashTableSlot;

struct HashTable {
  int           ht_size, ht_nPairs;
  HashTableSlot *ht_slots;
};

#define HASH_INCREMENT_SIZE	5

#define hashtable_slot(ht,index)	      (&((ht)->ht_slots[index]))
#define hashtable_hash_index(ht,key)	      (hash_string((key), (ht)->ht_size))
#define hashtable_compare_keys(ht,key1,key2)  (compare_strings((key1),(key2)))

static int compare_strings (char *key1, char *key2)
{
  return (strcmp(key1, key2) == 0);
}

static int hash_string (char * str, int size)
{
  unsigned long crc;

  crc = crc32(0L, NULL, 0);
  crc = crc32(crc, str, strlen(str));
  return (crc % size);
}

void * _plkr_FindInTable (HashTable *ht, char *key)
{
  HashTableSlot *slot;
  int count;

  if (ht == NULL)
    return (NULL);
  slot = hashtable_slot(ht, hashtable_hash_index(ht, key));
  for (count = slot->hs_count; count > 0; count -= 1)
    if (hashtable_compare_keys(ht, key, slot->hs_entries[count - 1].he_key))
      return (slot->hs_entries[count - 1].he_data);
  return (NULL);
}

void * _plkr_RemoveFromTable (HashTable *ht, char * key)
{
  HashTableSlot *slot;
  int count;

  if (ht == NULL)
    return (NULL);

  slot = hashtable_slot(ht,hashtable_hash_index(ht, key));
  for (count = 0;  count  < slot->hs_count;  count += 1)
    if (hashtable_compare_keys(ht, slot->hs_entries[count].he_key, key)) {
      void * data = slot->hs_entries[count].he_data;
      free(slot->hs_entries[count].he_key);
      if ((1 + (unsigned) count) < (unsigned) slot->hs_count)
        slot->hs_entries[count] = slot->hs_entries[slot->hs_count-1];
      --ht->ht_nPairs;
      if (--slot->hs_count <= 0)
        {
          free(slot->hs_entries);
          slot->hs_entries = NULL;
          slot->hs_allocated = 0;
          slot->hs_count = 0;
        }
      return (data);
    }
  return (NULL);
}

int _plkr_AddToTable(HashTable *ht, char * key, void * obj)
{
  HashTableSlot *slot;
  int count;

  if (ht == NULL)
    return (0);

  slot = hashtable_slot(ht, hashtable_hash_index(ht, key));

  for (count = slot->hs_count; count > 0; count -= 1)
    if (hashtable_compare_keys(ht, key, slot->hs_entries[count - 1].he_key))
      return (0);

  if (slot->hs_allocated == 0) {
    slot->hs_allocated = HASH_INCREMENT_SIZE;
    slot->hs_entries = (HashEntry *) malloc(sizeof(HashEntry) * slot->hs_allocated);
    slot->hs_count = 0;
  } else if (slot->hs_count >= slot->hs_allocated)
    slot->hs_entries = (HashEntry *) realloc(slot->hs_entries,
                                                    (slot->hs_allocated += HASH_INCREMENT_SIZE)
                                                    * sizeof(HashEntry));
  slot->hs_entries[slot->hs_count].he_key = _plkr_strndup(key, strlen(key));
  slot->hs_entries[slot->hs_count].he_data = obj;
  slot->hs_count += 1;
  ht->ht_nPairs += 1;
  return (1);
}

HashTable *_plkr_NewHashTable (int size)
{
  HashTable * new = (HashTable *) malloc(sizeof(HashTable));

  new->ht_size = size;
  new->ht_nPairs = 0;
  new->ht_slots = (HashTableSlot *) malloc(sizeof(HashTableSlot) * size);
  memset((void *) (new->ht_slots), 0, sizeof(HashTableSlot) * size);
  return (new);
}