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/* table.h - definitions for tables for keeping track of allocated memory */
/* Copyright (C) 2001-2003 Free Software Foundation, Inc.
This file is part of GNU Bash, the Bourne-Again SHell.
Bash 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 3 of the License, or
(at your option) any later version.
Bash 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 Bash. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef _MTABLE_H
#define _MTABLE_H
#include "imalloc.h"
#ifdef MALLOC_REGISTER
/* values for flags byte. */
#define MT_ALLOC 0x01
#define MT_FREE 0x02
/*
* Memory table entry.
*
* MEM is the address of the allocated pointer.
* SIZE is the requested allocation size.
* FLAGS includes either MT_ALLOC (MEM is allocated) or MT_FREE (MEM is
* not allocated). Other flags later.
* FUNC is set to the name of the function doing the allocation (from the
* `tag' argument to register_alloc().
* FILE and LINE are the filename and line number of the last allocation
* and free (depending on STATUS) of MEM.
* NALLOC and NFREE are incremented on each allocation that returns MEM or
* each free of MEM, respectively (way to keep track of memory reuse
* and how well the free lists are working).
*
*/
typedef struct mr_table {
PTR_T mem;
size_t size;
char flags;
const char *func;
const char *file;
int line;
int nalloc, nfree;
} mr_table_t;
#define REG_TABLE_SIZE 8192
extern mr_table_t *mr_table_entry __P((PTR_T));
extern void mregister_alloc __P((const char *, PTR_T, size_t, const char *, int));
extern void mregister_free __P((PTR_T, int, const char *, int));
extern void mregister_describe_mem ();
extern void mregister_dump_table __P((void));
extern void mregister_table_init __P((void));
/* NOTE: HASH_MIX taken from dmalloc (http://dmalloc.com) */
/*
* void HASH_MIX
*
* DESCRIPTION:
*
* Mix 3 32-bit values reversibly. For every delta with one or two
* bits set, and the deltas of all three high bits or all three low
* bits, whether the original value of a,b,c is almost all zero or is
* uniformly distributed.
*
* If HASH_MIX() is run forward or backward, at least 32 bits in a,b,c
* have at least 1/4 probability of changing. If mix() is run
* forward, every bit of c will change between 1/3 and 2/3 of the
* time. (Well, 22/100 and 78/100 for some 2-bit deltas.)
*
* HASH_MIX() takes 36 machine instructions, but only 18 cycles on a
* superscalar machine (like a Pentium or a Sparc). No faster mixer
* seems to work, that's the result of my brute-force search. There
* were about 2^68 hashes to choose from. I only tested about a
* billion of those.
*/
#define HASH_MIX(a, b, c) \
do { \
a -= b; a -= c; a ^= (c >> 13); \
b -= c; b -= a; b ^= (a << 8); \
c -= a; c -= b; c ^= (b >> 13); \
a -= b; a -= c; a ^= (c >> 12); \
b -= c; b -= a; b ^= (a << 16); \
c -= a; c -= b; c ^= (b >> 5); \
a -= b; a -= c; a ^= (c >> 3); \
b -= c; b -= a; b ^= (a << 10); \
c -= a; c -= b; c ^= (b >> 15); \
} while(0)
#endif /* MALLOC_REGISTER */
#endif /* _MTABLE_H */
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