1/* table.h - definitions for tables for keeping track of allocated memory */
2
3/*  Copyright (C) 2001-2003 Free Software Foundation, Inc.
4
5    This program is free software; you can redistribute it and/or modify
6    it under the terms of the GNU General Public License as published by
7    the Free Software Foundation; either version 2, or (at your option)
8    any later version.
9
10    This program is distributed in the hope that it will be useful,
11    but WITHOUT ANY WARRANTY; without even the implied warranty of
12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13    GNU General Public License for more details.
14
15    You should have received a copy of the GNU General Public License
16    along with this program; if not, write to the Free Software
17    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111 USA. */
18
19#ifndef _MTABLE_H
20#define _MTABLE_H
21
22#include "imalloc.h"
23
24#ifdef MALLOC_REGISTER
25
26/* values for flags byte. */
27#define MT_ALLOC	0x01
28#define MT_FREE		0x02
29
30/*
31 * Memory table entry.
32 *
33 * MEM is the address of the allocated pointer.
34 * SIZE is the requested allocation size.
35 * FLAGS includes either MT_ALLOC (MEM is allocated) or MT_FREE (MEM is
36 * not allocated).  Other flags later.
37 * FUNC is set to the name of the function doing the allocation (from the
38 * `tag' argument to register_alloc().
39 * FILE and LINE are the filename and line number of the last allocation
40 * and free (depending on STATUS) of MEM.
41 * NALLOC and NFREE are incremented on each allocation that returns MEM or
42 * each free of MEM, respectively (way to keep track of memory reuse
43 * and how well the free lists are working).
44 *
45 */
46typedef struct mr_table {
47	PTR_T mem;
48	size_t size;
49	char flags;
50	const char *func;
51	const char *file;
52	int line;
53	int nalloc, nfree;
54} mr_table_t;
55
56#define REG_TABLE_SIZE	8192
57
58extern mr_table_t *mr_table_entry __P((PTR_T));
59extern void mregister_alloc __P((const char *, PTR_T, size_t, const char *, int));
60extern void mregister_free __P((PTR_T, int, const char *, int));
61extern void mregister_describe_mem ();
62extern void mregister_dump_table __P((void));
63extern void mregister_table_init __P((void));
64
65/* NOTE:  HASH_MIX taken from dmalloc (http://dmalloc.com) */
66
67/*
68 * void HASH_MIX
69 *
70 * DESCRIPTION:
71 *
72 * Mix 3 32-bit values reversibly.  For every delta with one or two
73 * bits set, and the deltas of all three high bits or all three low
74 * bits, whether the original value of a,b,c is almost all zero or is
75 * uniformly distributed.
76 *
77 * If HASH_MIX() is run forward or backward, at least 32 bits in a,b,c
78 * have at least 1/4 probability of changing.  If mix() is run
79 * forward, every bit of c will change between 1/3 and 2/3 of the
80 * time.  (Well, 22/100 and 78/100 for some 2-bit deltas.)
81 *
82 * HASH_MIX() takes 36 machine instructions, but only 18 cycles on a
83 * superscalar machine (like a Pentium or a Sparc).  No faster mixer
84 * seems to work, that's the result of my brute-force search.  There
85 * were about 2^68 hashes to choose from.  I only tested about a
86 * billion of those.
87 */
88#define HASH_MIX(a, b, c) \
89 do { \
90   a -= b; a -= c; a ^= (c >> 13); \
91   b -= c; b -= a; b ^= (a << 8); \
92   c -= a; c -= b; c ^= (b >> 13); \
93   a -= b; a -= c; a ^= (c >> 12); \
94   b -= c; b -= a; b ^= (a << 16); \
95   c -= a; c -= b; c ^= (b >> 5); \
96   a -= b; a -= c; a ^= (c >> 3); \
97   b -= c; b -= a; b ^= (a << 10); \
98   c -= a; c -= b; c ^= (b >> 15); \
99 } while(0)
100
101#endif /* MALLOC_REGISTER */
102
103#endif /* _MTABLE_H */
104