
/*--------------------------------------------------------------------*/
/*--- An expandable array implementation.        pub_tool_xarray.h ---*/
/*--------------------------------------------------------------------*/

/*
   This file is part of Valgrind, a dynamic binary instrumentation
   framework.

   Copyright (C) 2007-2009 OpenWorks LLP
      info@open-works.co.uk

   This program is free software; you can redistribute it and/or
   modify it under the terms of the GNU General Public License as
   published by the Free Software Foundation; either version 2 of the
   License, or (at your option) any later version.

   This program is distributed in the hope that it will be useful, but
   WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   02111-1307, USA.

   The GNU General Public License is contained in the file COPYING.
*/

#ifndef __PUB_TOOL_XARRAY_H
#define __PUB_TOOL_XARRAY_H

//--------------------------------------------------------------------
// PURPOSE: Provides a simple but useful structure, which is an array
// in which elements can be added at the end.  The array is expanded
// as needed by multiplying its size by a constant factor (usually 2).
// This gives amortised O(1) insertion cost, and, following sorting,
// the usual O(log N) binary search cost.  Arbitrary element sizes
// are allowed; the comparison function for sort/lookup can be changed
// at any time, and duplicates (modulo the comparison function) are
// allowed.
//--------------------------------------------------------------------


/* It's an abstract type.  Bwaha. */
typedef  struct _XArray  XArray;

/* Create new XArray, using given allocation and free function, and
   for elements of the specified size.  Alloc fn must not fail (that
   is, if it returns it must have succeeded.) */
extern XArray* VG_(newXA) ( void*(*alloc_fn)(HChar*,SizeT), 
                            HChar* cc,
                            void(*free_fn)(void*),
                            Word elemSzB );

/* Free all memory associated with an XArray. */
extern void VG_(deleteXA) ( XArray* );

/* Set the comparison function for this XArray.  This clears an
   internal 'array is sorted' flag, which means you must call sortXA
   before making further queries with lookupXA. */
extern void VG_(setCmpFnXA) ( XArray*, Int (*compar)(void*,void*) );

/* Add an element to an XArray.  Element is copied into the XArray.
   Index at which it was added is returned.  Note this will be
   invalidated if the array is later sortXA'd. */
extern Word VG_(addToXA) ( XArray*, void* elem );

/* Add a sequence of bytes to an XArray of bytes.  Asserts if nbytes
   is negative or the array's element size is not 1.  Returns the
   index at which the first byte was added. */
extern Word VG_(addBytesToXA) ( XArray* xao, void* bytesV, Word nbytes );

/* Sort an XArray using its comparison function, if set; else bomb.
   Probably not a stable sort w.r.t. equal elements module cmpFn. */
extern void VG_(sortXA) ( XArray* );

/* Lookup (by binary search) 'key' in the array.  Set *first to be the
   index of the first, and *last to be the index of the last matching
   value found.  If any values are found, return True, else return
   False, and don't change *first or *last.  Bomb if the array is not
   sorted. */
extern Bool VG_(lookupXA) ( XArray*, void* key, 
                            /*OUT*/Word* first, /*OUT*/Word* last );

/* A version of VG_(lookupXA) in which you can specify your own
   comparison function.  This is unsafe in the sense that if the array
   is not totally ordered as defined by your comparison function, then
   this function may loop indefinitely, so it is up to you to ensure
   that the array is suitably ordered.  This is in comparison to
   VG_(lookupXA), which refuses to do anything (asserts) unless the
   array has first been sorted using the same comparison function as
   is being used for the lookup. */
extern Bool VG_(lookupXA_UNSAFE) ( XArray* xao, void* key,
                                   /*OUT*/Word* first, /*OUT*/Word* last,
                                   Int(*cmpFn)(void*,void*) );

/* How elements are there in this XArray now? */
extern Word VG_(sizeXA) ( XArray* );

/* Index into the XArray.  Checks bounds and bombs if the index is
   invalid.  What this returns is the address of the specified element
   in the array, not (of course) the element itself.  Note that the
   element may get moved by subsequent addToXAs/sortXAs, so you should
   copy it out immediately and not regard its address as unchanging.
   Note also that indexXA will of course not return NULL if it
   succeeds. */
extern void* VG_(indexXA) ( XArray*, Word );

/* Drop the last n elements of an XArray.  Bombs if there are less
   than n elements in the array.  This is an O(1) operation. */
extern void VG_(dropTailXA) ( XArray*, Word );

/* Drop the first n elements of an XArray.  Bombs if there are less
   than n elements in the array.  This is an O(N) operation, where N
   is the number of elements remaining in the XArray. */
extern void VG_(dropHeadXA) ( XArray*, Word );

/* Make a new, completely independent copy of the given XArray, using
   the existing allocation function to allocate the new space.
   Returns NULL if the allocation function didn't manage to allocate
   space (but did return NULL rather than merely abort.)  Space for
   the clone (and all additions to it) is billed to 'cc' unless that
   is NULL, in which case the parent's cost-center is used. */
extern XArray* VG_(cloneXA)( HChar* cc, XArray* xa );

#endif   // __PUB_TOOL_XARRAY_H

/*--------------------------------------------------------------------*/
/*--- end                                        pub_tool_xarray.h ---*/
/*--------------------------------------------------------------------*/
