From e5888a1ffdae813d7575f5fb02275c6bb07e5199 Mon Sep 17 00:00:00 2001
From: Taru Karttunen <taruti@taruti.net>
Date: Wed, 30 Mar 2011 15:46:40 +0300
Subject: Import sources from 2011-03-30 iso image

---
 sys/src/ape/lib/ap/plan9/malloc.c | 142 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 142 insertions(+)
 create mode 100755 sys/src/ape/lib/ap/plan9/malloc.c

(limited to 'sys/src/ape/lib/ap/plan9/malloc.c')

diff --git a/sys/src/ape/lib/ap/plan9/malloc.c b/sys/src/ape/lib/ap/plan9/malloc.c
new file mode 100755
index 000000000..09f3c178e
--- /dev/null
+++ b/sys/src/ape/lib/ap/plan9/malloc.c
@@ -0,0 +1,142 @@
+#include <stdlib.h>
+#include <string.h>
+
+typedef unsigned int	uint;
+
+enum
+{
+	MAGIC		= 0xbada110c,
+	MAX2SIZE	= 32,
+	CUTOFF		= 12,
+};
+
+typedef struct Bucket Bucket;
+struct Bucket
+{
+	int	size;
+	int	magic;
+	Bucket	*next;
+	int	pad;
+	char	data[1];
+};
+
+typedef struct Arena Arena;
+struct Arena
+{
+	Bucket	*btab[MAX2SIZE];	
+};
+static Arena arena;
+
+#define datoff		((int)((Bucket*)0)->data)
+#define nil		((void*)0)
+
+extern	void	*sbrk(unsigned long);
+
+void*
+malloc(size_t size)
+{
+	uint next;
+	int pow, n;
+	Bucket *bp, *nbp;
+
+	for(pow = 1; pow < MAX2SIZE; pow++) {
+		if(size <= (1<<pow))
+			goto good;
+	}
+
+	return nil;
+good:
+	/* Allocate off this list */
+	bp = arena.btab[pow];
+	if(bp) {
+		arena.btab[pow] = bp->next;
+
+		if(bp->magic != 0)
+			abort();
+
+		bp->magic = MAGIC;
+		return  bp->data;
+	}
+	size = sizeof(Bucket)+(1<<pow);
+	size += 7;
+	size &= ~7;
+
+	if(pow < CUTOFF) {
+		n = (CUTOFF-pow)+2;
+		bp = sbrk(size*n);
+		if((int)bp < 0)
+			return nil;
+
+		next = (uint)bp+size;
+		nbp = (Bucket*)next;
+		arena.btab[pow] = nbp;
+		for(n -= 2; n; n--) {
+			next = (uint)nbp+size;
+			nbp->next = (Bucket*)next;
+			nbp->size = pow;
+			nbp = nbp->next;
+		}
+		nbp->size = pow;
+	}
+	else {
+		bp = sbrk(size);
+		if((int)bp < 0)
+			return nil;
+	}
+		
+	bp->size = pow;
+	bp->magic = MAGIC;
+
+	return bp->data;
+}
+
+void
+free(void *ptr)
+{
+	Bucket *bp, **l;
+
+	if(ptr == nil)
+		return;
+
+	/* Find the start of the structure */
+	bp = (Bucket*)((uint)ptr - datoff);
+
+	if(bp->magic != MAGIC)
+		abort();
+
+	bp->magic = 0;
+	l = &arena.btab[bp->size];
+	bp->next = *l;
+	*l = bp;
+}
+
+void*
+realloc(void *ptr, size_t n)
+{
+	void *new;
+	uint osize;
+	Bucket *bp;
+
+	if(ptr == nil)
+		return malloc(n);
+
+	/* Find the start of the structure */
+	bp = (Bucket*)((uint)ptr - datoff);
+
+	if(bp->magic != MAGIC)
+		abort();
+
+	/* enough space in this bucket */
+	osize = 1<<bp->size;
+	if(osize >= n)
+		return ptr;
+
+	new = malloc(n);
+	if(new == nil)
+		return nil;
+
+	memmove(new, ptr, osize);
+	free(ptr);
+
+	return new;
+}
-- 
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