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/* Copyright (c) 1990 Regents of the University of California */ |
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#ifndef lint |
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static char SCCSid[] = "$SunId$ LBL"; |
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static const char RCSid[] = "$Id$"; |
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#endif |
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/* |
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* Simple memory allocation without overhead |
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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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* External symbols declared in standard.h |
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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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#include "copyright.h" |
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#include <stdlib.h> |
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#include "rtmisc.h" |
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#ifndef ALIGNT |
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#define ALIGNT double /* type for alignment */ |
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#endif |
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#ifndef ALIGN |
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#define ALIGN int /* type for alignment */ |
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#define BYTES_WORD sizeof(ALIGNT) |
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#ifndef MBLKSIZ /* size of memory allocation block */ |
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#define MBLKSIZ ((1<<15)-BYTES_WORD) |
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#endif |
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#define BYTES_WORD sizeof(ALIGN) |
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#define WASTEFRAC 12 /* don't waste more than a fraction */ |
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static char *bposition = NULL; |
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static size_t nremain = 0; |
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char * |
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bmalloc(n) /* allocate a block of n bytes, no refunds */ |
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register unsigned n; |
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void * |
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bmalloc( /* quickly allocate a block of n bytes */ |
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size_t n |
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) |
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{ |
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static char *bpos = NULL; |
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static unsigned nrem = 0; |
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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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if (n > MBLKSIZ/2) /* too big for me */ |
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return(malloc(n)); |
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n = (n+(BYTES_WORD-1)) & ~(BYTES_WORD-1); /* word align */ |
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n = (n+(BYTES_WORD-1))&~(BYTES_WORD-1); /* word align */ |
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if (n > nrem) { |
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if ((bpos = malloc((unsigned)MBLKSIZ)) == NULL) { |
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nrem = 0; |
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return(NULL); |
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} |
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nrem = MBLKSIZ; |
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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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bpos += n; |
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nrem -= n; |
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return(bpos - n); |
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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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bfree(p, n) /* free random memory */ |
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char *p; |
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unsigned n; |
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void |
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bfree( /* free some memory; anything in process space */ |
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void *pp, |
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size_t n |
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) |
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{ |
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/* not implemented */ |
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char *p = pp; |
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size_t bsiz; |
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/* check alignment */ |
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bsiz = BYTES_WORD - ((size_t)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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} |
