| 1 |
greg |
1.1 |
#ifndef lint |
| 2 |
schorsch |
2.6 |
static const char RCSid[] = "$Id: bmalloc.c,v 2.5 2003/07/17 09:21:29 schorsch Exp $"; |
| 3 |
greg |
1.1 |
#endif |
| 4 |
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/* |
| 5 |
greg |
1.3 |
* Bmalloc provides basic memory allocation without overhead (no free lists). |
| 6 |
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* Use only to take the load off of malloc for all those |
| 7 |
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* piddling little requests that you never expect to free. |
| 8 |
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* Bmalloc defers to malloc for big requests. |
| 9 |
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* Bfree should hand memory to bmalloc, but it usually fails here. |
| 10 |
greg |
2.3 |
* |
| 11 |
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* External symbols declared in standard.h |
| 12 |
greg |
1.1 |
*/ |
| 13 |
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| 14 |
greg |
2.4 |
#include "copyright.h" |
| 15 |
greg |
2.3 |
|
| 16 |
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#include <stdlib.h> |
| 17 |
schorsch |
2.5 |
|
| 18 |
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#include "rtmisc.h" |
| 19 |
greg |
1.2 |
|
| 20 |
greg |
1.1 |
#ifndef MBLKSIZ |
| 21 |
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#define MBLKSIZ 16376 /* size of memory allocation block */ |
| 22 |
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#endif |
| 23 |
greg |
1.3 |
#define WASTEFRAC 12 /* don't waste more than a fraction */ |
| 24 |
greg |
2.3 |
#ifndef ALIGNT |
| 25 |
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#define ALIGNT double /* type for alignment */ |
| 26 |
greg |
1.1 |
#endif |
| 27 |
greg |
2.3 |
#define BYTES_WORD sizeof(ALIGNT) |
| 28 |
greg |
1.1 |
|
| 29 |
greg |
1.3 |
static char *bposition = NULL; |
| 30 |
greg |
2.3 |
static unsigned int nremain = 0; |
| 31 |
greg |
1.3 |
|
| 32 |
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| 33 |
greg |
1.1 |
char * |
| 34 |
schorsch |
2.6 |
bmalloc( /* allocate a block of n bytes */ |
| 35 |
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register unsigned int n |
| 36 |
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) |
| 37 |
greg |
1.1 |
{ |
| 38 |
greg |
1.3 |
if (n > nremain && (n > MBLKSIZ || nremain > MBLKSIZ/WASTEFRAC)) |
| 39 |
greg |
1.2 |
return(malloc(n)); /* too big */ |
| 40 |
greg |
1.1 |
|
| 41 |
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n = (n+(BYTES_WORD-1))&~(BYTES_WORD-1); /* word align */ |
| 42 |
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| 43 |
greg |
2.3 |
if (n > nremain && (bposition = (char *)malloc(nremain = MBLKSIZ)) == NULL) { |
| 44 |
greg |
2.2 |
nremain = 0; |
| 45 |
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return(NULL); |
| 46 |
greg |
1.1 |
} |
| 47 |
greg |
1.3 |
bposition += n; |
| 48 |
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nremain -= n; |
| 49 |
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return(bposition - n); |
| 50 |
greg |
1.1 |
} |
| 51 |
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| 52 |
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| 53 |
greg |
2.3 |
void |
| 54 |
schorsch |
2.6 |
bfree( /* free random memory */ |
| 55 |
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register char *p, |
| 56 |
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register unsigned int n |
| 57 |
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) |
| 58 |
greg |
1.1 |
{ |
| 59 |
greg |
2.3 |
register unsigned int bsiz; |
| 60 |
greg |
1.3 |
/* check alignment */ |
| 61 |
greg |
2.3 |
bsiz = BYTES_WORD - ((unsigned int)p&(BYTES_WORD-1)); |
| 62 |
greg |
1.3 |
if (bsiz < BYTES_WORD) { |
| 63 |
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p += bsiz; |
| 64 |
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n -= bsiz; |
| 65 |
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} |
| 66 |
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if (p + n == bposition) { /* just allocated? */ |
| 67 |
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bposition = p; |
| 68 |
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nremain += n; |
| 69 |
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return; |
| 70 |
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} |
| 71 |
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if (n > nremain) { /* better than what we've got? */ |
| 72 |
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bposition = p; |
| 73 |
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nremain = n; |
| 74 |
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return; |
| 75 |
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} |
| 76 |
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/* just throw it away, then */ |
| 77 |
greg |
1.1 |
} |
