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Creating-and-Freeing-a-Hash-Table.html 5.2KB

3 年之前
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  68. <a name="Creating-and-freeing-a-hash-table"></a>
  69. <h4 class="subsection">2.18.1 Creating and freeing a hash table</h4>
  70. <a name="index-bfd_005fhash_005ftable_005finit"></a>
  71. <a name="index-bfd_005fhash_005ftable_005finit_005fn"></a>
  72. <p>To create a hash table, create an instance of a <code>struct
  73. bfd_hash_table</code> (defined in <code>bfd.h</code>) and call
  74. <code>bfd_hash_table_init</code> (if you know approximately how many
  75. entries you will need, the function <code>bfd_hash_table_init_n</code>,
  76. which takes a <var>size</var> argument, may be used).
  77. <code>bfd_hash_table_init</code> returns <code>FALSE</code> if some sort of
  78. error occurs.
  79. </p>
  80. <a name="index-bfd_005fhash_005fnewfunc"></a>
  81. <p>The function <code>bfd_hash_table_init</code> take as an argument a
  82. function to use to create new entries. For a basic hash
  83. table, use the function <code>bfd_hash_newfunc</code>. See <a href="Deriving-a-New-Hash-Table-Type.html#Deriving-a-New-Hash-Table-Type">Deriving a New Hash Table Type</a>, for why you would want to use a
  84. different value for this argument.
  85. </p>
  86. <a name="index-bfd_005fhash_005fallocate"></a>
  87. <p><code>bfd_hash_table_init</code> will create an objalloc which will be
  88. used to allocate new entries. You may allocate memory on this
  89. objalloc using <code>bfd_hash_allocate</code>.
  90. </p>
  91. <a name="index-bfd_005fhash_005ftable_005ffree"></a>
  92. <p>Use <code>bfd_hash_table_free</code> to free up all the memory that has
  93. been allocated for a hash table. This will not free up the
  94. <code>struct bfd_hash_table</code> itself, which you must provide.
  95. </p>
  96. <a name="index-bfd_005fhash_005fset_005fdefault_005fsize"></a>
  97. <p>Use <code>bfd_hash_set_default_size</code> to set the default size of
  98. hash table to use.
  99. </p>
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