src/plugins/mailmbox/chash.h

   1
   2 /*
   3  * libEtPan! -- a mail stuff library
   4  *
   5  * chash - Implements generic hash tables.
   6  *
   7  * Copyright (c) 1999-2000, Gaël Roualland <gael.roualland@iname.com>
   8  * interface changes - 2002 - DINH Viet Hoa
   9  * All rights reserved.
  10  *
  11  * Redistribution and use in source and binary forms, with or without
  12  * modification, are permitted provided that the following conditions
  13  * are met:
  14  * 1. Redistributions of source code must retain the above copyright
  15  *    notice, this list of conditions and the following disclaimer.
  16  * 2. Redistributions in binary form must reproduce the above copyright
  17  *    notice, this list of conditions and the following disclaimer in the
  18  *    documentation and/or other materials provided with the distribution.
  19  * 3. Neither the name of the libEtPan! project nor the names of its
  20  *    contributors may be used to endorse or promote products derived
  21  *    from this software without specific prior written permission.
  22  *
  23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  33  * SUCH DAMAGE.
  34  */
  35
  36 /*
  37  * $Id$
  38  */
  39
  40 #ifndef CHASH_H
  41 #define CHASH_H
  42
  43 #ifdef __cplusplus
  44 extern "C" {
  45 #endif
  46
  47 typedef struct {
  48   void * data;
  49   unsigned int len;
  50 } chashdatum;
  51
  52 struct chash {
  53   unsigned int size;
  54   unsigned int count;
  55   int copyvalue;
  56   int copykey;
  57   struct chashcell ** cells;
  58 };
  59
  60 typedef struct chash chash;
  61
  62 struct chashcell {
  63   unsigned int func;
  64   chashdatum key;
  65   chashdatum value;
  66   struct chashcell * next;
  67 };
  68
  69 typedef struct chashcell chashiter;
  70
  71 #define CHASH_COPYNONE    0
  72 #define CHASH_COPYKEY     1
  73 #define CHASH_COPYVALUE   2
  74 #define CHASH_COPYALL     (CHASH_COPYKEY | CHASH_COPYVALUE)
  75
  76 #define CHASH_DEFAULTSIZE 13
  77
  78 /* Allocates a new (empty) hash using this initial size and the given flags,
  79    specifying which data should be copied in the hash.
  80     CHASH_COPYNONE  : Keys/Values are not copied.
  81     CHASH_COPYKEY   : Keys are dupped and freed as needed in the hash.
  82     CHASH_COPYVALUE : Values are dupped and freed as needed in the hash.
  83     CHASH_COPYALL   : Both keys and values are dupped in the hash.
  84  */
  85 chash * chash_new(unsigned int size, int flags);
  86
  87 /* Frees a hash */
  88 void chash_free(chash * hash);
  89
  90 /* Removes all elements from a hash */
  91 void chash_clear(chash * hash);
  92
  93 /* Adds an entry in the hash table.
  94    Length can be 0 if key/value are strings.
  95    If an entry already exists for this key, it is replaced, and its value
  96    is returned. Otherwise, the data pointer will be NULL and the length
  97    field be set to TRUE or FALSe to indicate success or failure. */
  98 int chash_set(chash * hash,
  99               chashdatum * key,
 100               chashdatum * value,
 101               chashdatum * oldvalue);
 102
 103 /* Retrieves the data associated to the key if it is found in the hash table.
 104    The data pointer and the length will be NULL if not found*/
 105 int chash_get(chash * hash,
 106               chashdatum * key, chashdatum * result);
 107
 108 /* Removes the entry associated to this key if it is found in the hash table,
 109    and returns its contents if not dupped (otherwise, pointer will be NULL
 110    and len TRUE). If entry is not found both pointer and len will be NULL. */
 111 int chash_delete(chash * hash,
 112                  chashdatum * key,
 113                  chashdatum * oldvalue);
 114
 115 /* Resizes the hash table to the passed size. */
 116 int chash_resize(chash * hash, unsigned int size);
 117
 118 /* Returns an iterator to the first non-empty entry of the hash table */
 119 chashiter * chash_begin(chash * hash);
 120
 121 /* Returns the next non-empty entry of the hash table */
 122 chashiter * chash_next(chash * hash, chashiter * iter);
 123
 124 /* Some of the following routines can be implemented as macros to
 125    be faster. If you don't want it, define NO_MACROS */
 126 #ifdef NO_MACROS
 127 /* Returns the size of the hash table */
 128 unsigned int          chash_size(chash * hash);
 129
 130 /* Returns the number of entries in the hash table */
 131 unsigned int          chash_count(chash * hash);
 132
 133 /* Returns the key part of the entry pointed by the iterator */
 134 void chash_key(chashiter * iter, chashdatum * result);
 135
 136 /* Returns the value part of the entry pointed by the iterator */
 137 void chash_value(chashiter * iter, chashdatum * result);
 138
 139 #else
 140 static inline unsigned int chash_size(chash * hash)
 141 {
 142   return hash->size;
 143 }
 144
 145 static inline unsigned int chash_count(chash * hash)
 146 {
 147   return hash->count;
 148 }
 149
 150 static inline void chash_key(chashiter * iter, chashdatum * result)
 151 {
 152   * result = iter->key;
 153 }
 154
 155 static inline void chash_value(chashiter * iter, chashdatum * result)
 156 {
 157   * result = iter->value;
 158 }
 159
 160 #endif
 161
 162 #ifdef __cplusplus
 163 }
 164 #endif
 165
 166 #endif