mirror of
https://github.com/Zenithsiz/ftmemsim-valgrind.git
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0e70d01bdd
Allow hashtables to dynamically resize (patch from Christoph
Bartoschek). Results in the following interface changes:
* HT_construct: no need to supply an initial table size.
Instead, supply a text string used to "name" the table, so
that debugging messages ("resizing the table") can say which
one they are resizing.
* Remove VG_(HT_get_node). This exposes the chain structure to
callers (via the next_ptr parameter), which is a problem since
callers could get some info about the chain structure which then
changes when the table is resized. Fortunately is not used.
* Remove VG_(HT_first_match) and VG_(HT_apply_to_all_nodes) as
they are unused.
* Make the iteration mechanism more paranoid, so any adding or
deleting of nodes part way through an iteration causes VG_(HT_next)
to assert.
* Fix the comment on VG_(HT_to_array) so it no longer speaks
specifically about MC's leak detector.
git-svn-id: svn://svn.valgrind.org/valgrind/trunk@6778
101 lines
3.9 KiB
C
101 lines
3.9 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) 2005-2007 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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/* 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. */
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extern VgHashTable VG_(HT_construct) ( HChar* name );
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/* Count the number of nodes in a table. */
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extern Int VG_(HT_count_nodes) ( VgHashTable table );
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/* Add a node to the table. */
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extern void VG_(HT_add_node) ( VgHashTable t, void* node );
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/* Looks up a VgHashNode in the table. Returns NULL if not found. */
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extern void* VG_(HT_lookup) ( VgHashTable table, UWord key );
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/* Removes a VgHashNode 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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/* Allocates a suitably-sized array, copies all the hashtable elements
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into it, then returns both the array and the size of it. This is
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used by the memory-leak detector. The array must be freed with
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VG_(free). */
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extern VgHashNode** VG_(HT_to_array) ( VgHashTable t, /*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. */
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extern void VG_(HT_destruct) ( VgHashTable t );
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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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