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/* Copyright (c) 1991 Regents of the University of California */ |
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|
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#ifndef lint |
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static char SCCSid[] = "$SunId$ LBL"; |
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#endif |
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|
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/* |
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* Bmalloc provides basic memory allocation without overhead (no free lists). |
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* Use only to take the load off of malloc for all those |
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* piddling little requests that you never expect to free. |
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* Bmalloc defers to malloc for big requests. |
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* Bfree should hand memory to bmalloc, but it usually fails here. |
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*/ |
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|
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#define NULL 0 |
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|
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#ifndef MBLKSIZ |
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#define MBLKSIZ 16376 /* size of memory allocation block */ |
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#endif |
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#define WASTEFRAC 12 /* don't waste more than a fraction */ |
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#ifndef ALIGN |
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#define ALIGN int /* type for alignment */ |
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#endif |
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#define BYTES_WORD sizeof(ALIGN) |
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|
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extern char *malloc(); |
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|
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static char *bposition = NULL; |
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static unsigned nremain = 0; |
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|
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|
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char * |
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bmalloc(n) /* allocate a block of n bytes */ |
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register unsigned n; |
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{ |
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if (n > nremain && (n > MBLKSIZ || nremain > MBLKSIZ/WASTEFRAC)) |
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return(malloc(n)); /* too big */ |
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|
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n = (n+(BYTES_WORD-1))&~(BYTES_WORD-1); /* word align */ |
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|
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if (n > nremain && (bposition = malloc(nremain = MBLKSIZ)) == NULL) { |
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nremain = 0; |
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return(NULL); |
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} |
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bposition += n; |
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nremain -= n; |
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return(bposition - n); |
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} |
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|
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|
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bfree(p, n) /* free random memory */ |
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register char *p; |
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register unsigned n; |
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{ |
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register unsigned bsiz; |
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/* check alignment */ |
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bsiz = BYTES_WORD - ((unsigned)p&(BYTES_WORD-1)); |
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if (bsiz < BYTES_WORD) { |
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p += bsiz; |
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n -= bsiz; |
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} |
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if (p + n == bposition) { /* just allocated? */ |
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bposition = p; |
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nremain += n; |
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return; |
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} |
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if (n > nremain) { /* better than what we've got? */ |
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bposition = p; |
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nremain = n; |
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return; |
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} |
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/* just throw it away, then */ |
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} |
