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https://github.com/ioacademy-jikim/debugging
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134 lines
5.8 KiB
C
134 lines
5.8 KiB
C
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/*--------------------------------------------------------------------*/
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/*--- A hash table implementation. pub_tool_hashtable.h ---*/
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/*--------------------------------------------------------------------*/
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/*
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This file is part of Valgrind, a dynamic binary instrumentation
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framework.
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Copyright (C) 2005-2015 Nicholas Nethercote
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njn@valgrind.org
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307, USA.
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The GNU General Public License is contained in the file COPYING.
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*/
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#ifndef __PUB_TOOL_HASHTABLE_H
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#define __PUB_TOOL_HASHTABLE_H
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#include "pub_tool_basics.h" // VG_ macro
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/* Generic type for a separately-chained hash table. Via a kind of dodgy
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C-as-C++ style inheritance, tools can extend the VgHashNode type, so long
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as the first two fields match the sizes of these two fields. Requires
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a bit of casting by the tool. */
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// Problems with this data structure:
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// - Separate chaining gives bad cache behaviour. Hash tables with linear
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// probing give better cache behaviour.
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typedef
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struct _VgHashNode {
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struct _VgHashNode * next;
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UWord key;
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}
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VgHashNode;
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typedef struct _VgHashTable VgHashTable;
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/* Make a new table. Allocates the memory with VG_(calloc)(), so can
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be freed with VG_(free)(). The table starts small but will
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periodically be expanded. This is transparent to the users of this
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module. The function never returns NULL. */
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extern VgHashTable *VG_(HT_construct) ( const HChar* name );
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/* Count the number of nodes in a table. */
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extern UInt VG_(HT_count_nodes) ( const VgHashTable *table );
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/* Add a node to the table. Duplicate keys are permitted. */
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extern void VG_(HT_add_node) ( VgHashTable *t, void* node );
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/* Looks up a VgHashNode by key in the table.
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* Returns NULL if not found. If entries
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* with duplicate keys are present, the most recently-added of the dups will
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* be returned, but it's probably better to avoid dups altogether. */
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extern void* VG_(HT_lookup) ( const VgHashTable *table, UWord key );
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/* Removes a VgHashNode by key from the table. Returns NULL if not found. */
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extern void* VG_(HT_remove) ( VgHashTable *table, UWord key );
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typedef Word (*HT_Cmp_t) ( const void* node1, const void* node2 );
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/* Same as VG_(HT_lookup) and VG_(HT_remove), but allowing a part of or
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the full element to be compared for equality, not only the key.
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The typical use for the below function is to store a hash value of the
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element in the key, and have the comparison function checking for equality
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of the full element data.
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Attention about the comparison function:
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* It must *not* compare the 'next' pointer.
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* when comparing the rest of the node, if the node data contains holes
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between components, either the node memory should be fully initialised
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(e.g. allocated using VG_(calloc)) or each component should be compared
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individually.
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Note that the cmp function is only called for elements that already
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have keys that are equal. So, it is not needed for cmp to check for
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key equality. */
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extern void* VG_(HT_gen_lookup) ( const VgHashTable *table, const void* node,
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HT_Cmp_t cmp );
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extern void* VG_(HT_gen_remove) ( VgHashTable *table, const void* node,
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HT_Cmp_t cmp );
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/* Output detailed usage/collision statistics.
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cmp will be used to verify if 2 elements with the same key are equal.
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Use NULL cmp if the hash table elements are only to be compared by key. */
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extern void VG_(HT_print_stats) ( const VgHashTable *table, HT_Cmp_t cmp );
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/* Allocates a suitably-sized array, copies pointers to all the hashtable
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elements into it, then returns both the array and the size of it. The
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array must be freed with VG_(free). If the hashtable is empty, the
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function returns NULL and assigns *nelems = 0. */
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extern VgHashNode** VG_(HT_to_array) ( const VgHashTable *table,
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/*OUT*/ UInt* n_elems );
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/* Reset the table's iterator to point to the first element. */
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extern void VG_(HT_ResetIter) ( VgHashTable *table );
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/* Return the element pointed to by the iterator and move on to the
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next one. Returns NULL if the last one has been passed, or if
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HT_ResetIter() has not been called previously. Asserts if the
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table has been modified (HT_add_node, HT_remove) since
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HT_ResetIter. This guarantees that callers cannot screw up by
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modifying the table whilst iterating over it (and is necessary to
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make the implementation safe; specifically we must guarantee that
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the table will not get resized whilst iteration is happening.
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Since resizing only happens as a result of calling HT_add_node,
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disallowing HT_add_node during iteration should give the required
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assurance. */
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extern void* VG_(HT_Next) ( VgHashTable *table );
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/* Destroy a table and deallocates the memory used by the nodes using
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freenode_fn.*/
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extern void VG_(HT_destruct) ( VgHashTable *table, void(*freenode_fn)(void*) );
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#endif // __PUB_TOOL_HASHTABLE_H
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/*--------------------------------------------------------------------*/
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/*--- end ---*/
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/*--------------------------------------------------------------------*/
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