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1 
2 /*--------------------------------------------------------------------*/
3 /*--- An expandable array implementation.        pub_tool_xarray.h ---*/
4 /*--------------------------------------------------------------------*/
5 
6 /*
7    This file is part of Valgrind, a dynamic binary instrumentation
8    framework.
9 
10    Copyright (C) 2007-2013 OpenWorks LLP
11       info@open-works.co.uk
12 
13    This program is free software; you can redistribute it and/or
14    modify it under the terms of the GNU General Public License as
15    published by the Free Software Foundation; either version 2 of the
16    License, or (at your option) any later version.
17 
18    This program is distributed in the hope that it will be useful, but
19    WITHOUT ANY WARRANTY; without even the implied warranty of
20    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
21    General Public License for more details.
22 
23    You should have received a copy of the GNU General Public License
24    along with this program; if not, write to the Free Software
25    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
26    02111-1307, USA.
27 
28    The GNU General Public License is contained in the file COPYING.
29 */
30 
31 #ifndef __PUB_TOOL_XARRAY_H
32 #define __PUB_TOOL_XARRAY_H
33 
34 #include "pub_tool_basics.h"    // Word
35 
36 //--------------------------------------------------------------------
37 // PURPOSE: Provides a simple but useful structure, which is an array
38 // in which elements can be added at the end.  The array is expanded
39 // as needed by multiplying its size by a constant factor (usually 2).
40 // This gives amortised O(1) insertion cost, and, following sorting,
41 // the usual O(log N) binary search cost.  Arbitrary element sizes
42 // are allowed; the comparison function for sort/lookup can be changed
43 // at any time, and duplicates (modulo the comparison function) are
44 // allowed.
45 //--------------------------------------------------------------------
46 
47 
48 /* It's an abstract type.  Bwaha. */
49 typedef  struct _XArray  XArray;
50 
51 typedef Int (*XACmpFn_t)(const void *, const void *);
52 
53 /* Create new XArray, using given allocation and free function, and
54    for elements of the specified size.  Alloc fn must not fail (that
55    is, if it returns it must have succeeded.) */
56 extern XArray* VG_(newXA) ( void*(*alloc_fn)(const HChar*,SizeT),
57                             const HChar* cc,
58                             void(*free_fn)(void*),
59                             Word elemSzB );
60 
61 /* Free all memory associated with an XArray. */
62 extern void VG_(deleteXA) ( XArray* );
63 
64 /* Set the comparison function for this XArray.  This clears an
65    internal 'array is sorted' flag, which means you must call sortXA
66    before making further queries with lookupXA. */
67 extern void VG_(setCmpFnXA) ( XArray*, XACmpFn_t);
68 
69 /* Add an element to an XArray.  Element is copied into the XArray.
70    Index at which it was added is returned.  Note this will be
71    invalidated if the array is later sortXA'd. */
72 extern Word VG_(addToXA) ( XArray*, const void* elem );
73 
74 /* Add a sequence of bytes to an XArray of bytes.  Asserts if nbytes
75    is negative or the array's element size is not 1.  Returns the
76    index at which the first byte was added. */
77 extern Word VG_(addBytesToXA) ( XArray* xao, const void* bytesV, Word nbytes );
78 
79 /* Sort an XArray using its comparison function, if set; else bomb.
80    Probably not a stable sort w.r.t. equal elements module cmpFn. */
81 extern void VG_(sortXA) ( XArray* );
82 
83 /* Lookup (by binary search) 'key' in the array.  Set *first to be the
84    index of the first, and *last to be the index of the last matching
85    value found.  If any values are found, return True, else return
86    False, and don't change *first or *last.  first and/or last may be
87    NULL.  Bomb if the array is not sorted. */
88 extern Bool VG_(lookupXA) ( XArray*, const void* key,
89                             /*OUT*/Word* first, /*OUT*/Word* last );
90 
91 /* A version of VG_(lookupXA) in which you can specify your own
92    comparison function.  This is unsafe in the sense that if the array
93    is not totally ordered as defined by your comparison function, then
94    this function may loop indefinitely, so it is up to you to ensure
95    that the array is suitably ordered.  This is in comparison to
96    VG_(lookupXA), which refuses to do anything (asserts) unless the
97    array has first been sorted using the same comparison function as
98    is being used for the lookup. */
99 extern Bool VG_(lookupXA_UNSAFE) ( XArray* xao, const void* key,
100                                    /*OUT*/Word* first, /*OUT*/Word* last,
101                                    XACmpFn_t cmpFn );
102 
103 /* How elements are there in this XArray now? */
104 extern Word VG_(sizeXA) ( XArray* );
105 
106 /* Index into the XArray.  Checks bounds and bombs if the index is
107    invalid.  What this returns is the address of the specified element
108    in the array, not (of course) the element itself.  Note that the
109    element may get moved by subsequent calls to addToXA / sortXA /
110    insertIndexXA, so you should copy it out immediately and not regard
111    its address as unchanging.  Note also that indexXA will of course
112    not return NULL if it succeeds. */
113 extern void* VG_(indexXA) ( XArray*, Word );
114 
115 /* Drop the last n elements of an XArray.  Bombs if there are less
116    than n elements in the array.  This is an O(1) operation. */
117 extern void VG_(dropTailXA) ( XArray*, Word );
118 
119 /* Drop the first n elements of an XArray.  Bombs if there are less
120    than n elements in the array.  This is an O(N) operation, where N
121    is the number of elements remaining in the XArray. */
122 extern void VG_(dropHeadXA) ( XArray*, Word );
123 
124 /* Remove the specified element of an XArray, and slide all elements
125    beyond it back one place.  This is an O(N) operation, where N is
126    the number of elements after the specified element, in the
127    array. */
128 extern void VG_(removeIndexXA)( XArray*, Word );
129 
130 /* Insert an element into an XArray at the given index.  The existing
131    element at the index and all above it are slid upwards one slot so
132    as to make space.  Element is copied into the XArray.  This is an
133    O(N) operation, when N is the number of elements after the
134    specified element, in the array. */
135 extern void VG_(insertIndexXA)( XArray*, Word, const void* elem );
136 
137 /* Make a new, completely independent copy of the given XArray, using
138    the existing allocation function to allocate the new space.
139    Returns NULL if the allocation function didn't manage to allocate
140    space (but did return NULL rather than merely abort.)  Space for
141    the clone (and all additions to it) is billed to 'cc' unless that
142    is NULL, in which case the parent's cost-center is used. */
143 extern XArray* VG_(cloneXA)( const HChar* cc, XArray* xa );
144 
145 /* Get the raw array and size so callers can index it really fast.
146    This is dangerous in the sense that there's no range or
147    anything-else checking.  It's also dangerous in that if
148    VG_(addToXA) is used, the contents may be re-located without
149    warning, hence making the contents address returned here
150    invalid. */
151 extern void VG_(getContentsXA_UNSAFE)( XArray* sr,
152                                        /*OUT*/void** ctsP,
153                                        /*OUT*/Word*  usedP );
154 
155 /* Convenience function: printf into an XArray of HChar, adding stuff
156    at the end.  This is very convenient for concocting arbitrary
157    length printf output in an XArray.  Note that the resulting string
158    is NOT zero-terminated. */
159 extern void VG_(xaprintf)( XArray* dst, const HChar* format, ... )
160                          PRINTF_CHECK(2, 3);
161 
162 #endif   // __PUB_TOOL_XARRAY_H
163 
164 /*--------------------------------------------------------------------*/
165 /*--- end                                        pub_tool_xarray.h ---*/
166 /*--------------------------------------------------------------------*/
167