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#ifndef lint |
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static const char RCSid[] = "$Id: palloc.c,v 1.2 2003/06/08 12:03:10 schorsch Exp $"; |
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#endif |
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/* |
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* Limited dynamic storage allocator for primitives |
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*/ |
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|
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|
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#define FBSIZE 72 /* size of malloc call */ |
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|
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|
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#include "meta.h" |
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|
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|
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extern int maxalloc; /* number of prims to allocate */ |
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int nalloc = 0; /* number allocated so far */ |
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|
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static PLIST freelist = {NULL, NULL}; |
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|
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|
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static int morefree(void); |
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|
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|
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PRIMITIVE * |
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palloc(void) /* allocate a primitive */ |
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|
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{ |
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register PRIMITIVE *p; |
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|
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if (maxalloc > 0 && nalloc >= maxalloc) |
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return(NULL); |
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|
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if ((p = pop(&freelist)) == NULL) { |
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if (morefree()) |
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p = pop(&freelist); |
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else { |
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sprintf(errmsg, "out of memory in palloc (nalloc = %d)", nalloc); |
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error(SYSTEM, errmsg); |
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} |
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} |
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|
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nalloc++; |
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return(p); |
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} |
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|
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|
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|
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void |
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pfree( /* free a primitive */ |
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register PRIMITIVE *p |
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) |
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{ |
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|
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if (p->args != NULL) { |
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freestr(p->args); |
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p->args = NULL; |
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} |
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push(p, &freelist); |
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nalloc--; |
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|
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} |
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|
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|
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|
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void |
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plfree( /* free a primitive list */ |
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register PLIST *pl |
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) |
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{ |
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register PRIMITIVE *p; |
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|
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for (p = pl->ptop; p != NULL; p = p->pnext) { |
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if (p->args != NULL) { |
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freestr(p->args); |
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p->args = NULL; |
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} |
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nalloc--; |
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} |
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|
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append(pl, &freelist); |
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pl->ptop = pl->pbot = NULL; |
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|
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} |
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|
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|
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|
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static int |
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morefree(void) /* get more free space */ |
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|
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{ |
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register PRIMITIVE *p; |
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register int i; |
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int rnu; |
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|
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if (maxalloc > 0 && (i = maxalloc-nalloc) < FBSIZE) |
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rnu = i; |
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else |
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rnu = i = FBSIZE; |
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|
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p = (PRIMITIVE *)malloc((unsigned)i * sizeof(PRIMITIVE)); |
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|
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if (p == NULL) |
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return(0); |
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|
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while (i--) { |
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p->args = NULL; |
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push(p, &freelist); |
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p++; |
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} |
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|
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return(rnu); |
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} |
