1 |
greg |
1.3 |
/* Copyright (c) 1991 Regents of the University of California */ |
2 |
greg |
1.1 |
|
3 |
|
|
#ifndef lint |
4 |
|
|
static char SCCSid[] = "$SunId$ LBL"; |
5 |
|
|
#endif |
6 |
|
|
|
7 |
|
|
/* |
8 |
greg |
1.3 |
* Bmalloc provides basic memory allocation without overhead (no free lists). |
9 |
|
|
* Use only to take the load off of malloc for all those |
10 |
|
|
* piddling little requests that you never expect to free. |
11 |
|
|
* Bmalloc defers to malloc for big requests. |
12 |
|
|
* Bfree should hand memory to bmalloc, but it usually fails here. |
13 |
greg |
1.1 |
*/ |
14 |
|
|
|
15 |
greg |
1.2 |
#define NULL 0 |
16 |
|
|
|
17 |
greg |
1.1 |
#ifndef MBLKSIZ |
18 |
|
|
#define MBLKSIZ 16376 /* size of memory allocation block */ |
19 |
|
|
#endif |
20 |
greg |
1.3 |
#define WASTEFRAC 12 /* don't waste more than a fraction */ |
21 |
greg |
1.1 |
#ifndef ALIGN |
22 |
|
|
#define ALIGN int /* type for alignment */ |
23 |
|
|
#endif |
24 |
|
|
#define BYTES_WORD sizeof(ALIGN) |
25 |
|
|
|
26 |
greg |
1.3 |
extern char *malloc(); |
27 |
greg |
1.1 |
|
28 |
greg |
1.3 |
static char *bposition = NULL; |
29 |
|
|
static unsigned nremain = 0; |
30 |
|
|
|
31 |
|
|
|
32 |
greg |
1.1 |
char * |
33 |
greg |
2.2 |
bmalloc(n) /* allocate a block of n bytes */ |
34 |
greg |
1.1 |
register unsigned n; |
35 |
|
|
{ |
36 |
greg |
1.3 |
if (n > nremain && (n > MBLKSIZ || nremain > MBLKSIZ/WASTEFRAC)) |
37 |
greg |
1.2 |
return(malloc(n)); /* too big */ |
38 |
greg |
1.1 |
|
39 |
|
|
n = (n+(BYTES_WORD-1))&~(BYTES_WORD-1); /* word align */ |
40 |
|
|
|
41 |
greg |
2.2 |
if (n > nremain && (bposition = malloc(nremain = MBLKSIZ)) == NULL) { |
42 |
|
|
nremain = 0; |
43 |
|
|
return(NULL); |
44 |
greg |
1.1 |
} |
45 |
greg |
1.3 |
bposition += n; |
46 |
|
|
nremain -= n; |
47 |
|
|
return(bposition - n); |
48 |
greg |
1.1 |
} |
49 |
|
|
|
50 |
|
|
|
51 |
|
|
bfree(p, n) /* free random memory */ |
52 |
greg |
1.3 |
register char *p; |
53 |
|
|
register unsigned n; |
54 |
greg |
1.1 |
{ |
55 |
greg |
1.3 |
register unsigned bsiz; |
56 |
|
|
/* check alignment */ |
57 |
|
|
bsiz = BYTES_WORD - ((unsigned)p&(BYTES_WORD-1)); |
58 |
|
|
if (bsiz < BYTES_WORD) { |
59 |
|
|
p += bsiz; |
60 |
|
|
n -= bsiz; |
61 |
|
|
} |
62 |
|
|
if (p + n == bposition) { /* just allocated? */ |
63 |
|
|
bposition = p; |
64 |
|
|
nremain += n; |
65 |
|
|
return; |
66 |
|
|
} |
67 |
|
|
if (n > nremain) { /* better than what we've got? */ |
68 |
|
|
bposition = p; |
69 |
|
|
nremain = n; |
70 |
|
|
return; |
71 |
|
|
} |
72 |
|
|
/* just throw it away, then */ |
73 |
greg |
1.1 |
} |