1992/0618/port/malloc.c (diff list | history)

1992/0618/sys/src/9/port/malloc.c:1,85 – 1992/0619/sys/src/9/port/malloc.c:0 (short | long | prev)
Deleted. rsc Mon Mar 7 10:31:31 2005
1992/0612		#include <u.h> #include <libc.h>
1990/1210
1992/0612		enum { MAGIC = 0xDEADBABE,
1992/0618		MAXPOW = 20
1992/0612		};
1990/1210
1992/0612		typedef struct Bucket Bucket; struct Bucket
1990/1210		{
1992/0612		int size; int magic; Bucket *next; char data[1]; };
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1992/0612		typedef struct Arena Arena; struct Arena
1990/1210		{
1992/0612		Lock;
1992/0618		Bucket *btab[MAXPOW];
1992/0612		}; static Arena arena; #define datoff ((int)&((Bucket*)0)->data)
1990/1210		void*
1992/0612		malloc(uint size)
1990/1210		{
1992/0612		int pow; Bucket *bp;
1990/1210
1992/0618		size += sizeof(Bucket);                  for(pow = 1; pow < MAXPOW; pow++)
1992/0612		if(size <= (1<<pow)) goto good;
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1992/0618		return 0;
1992/0612		good: lock(&arena); bp = arena.btab[pow]; if(bp) { arena.btab[pow] = bp->next; arena.unlock();
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1992/0612		if(bp->magic != 0)
1992/0618		panic("malloc");
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1992/0612		bp->magic = MAGIC;
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1992/0612		memset(bp->data, 0, size); return bp->data;
1990/1210		}
1992/0612		unlock(&arena);
1992/0618
1992/0612		size = sizeof(Bucket)+(1<<pow);
1992/0618		bp = xbrk(size);
1992/0612		if((int)bp < 0) return nil;
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1992/0618		memset(bp->data, 0, size);
1992/0612		return bp->data;
1990/1210		}                  void
1992/0612		free(void *ptr)
1990/1210		{
1992/0612		Bucket *bp, **l;
1990/1210
1992/0612		/* Find the start of the structure */ bp = (Bucket*)((uint)ptr - datoff);
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1992/0612		if(bp->magic != MAGIC) panic("free");
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1992/0612		bp->magic = 0; lock(&arena); l = &arena.btab[bp->size]; bp->next = *l; *l = bp; unlock(&arena);
1990/1210		}