Mailing List Archive

# HG changeset patch
# User kaf24@firebug.cl.cam.ac.uk
# Node ID 4937d9f496abc4962ac6597dc0bf48b2aef8a0f7
# Parent fe039c5fd1272ccc98dc44a257957718c0519c08
Add a little more internal abstraction to the rangeset
library, avoiding direct interaction with the linked-list
structure.

Signed-off-by: Keir Fraser <keir@xensource.com>

diff -r fe039c5fd127 -r 4937d9f496ab xen/common/rangeset.c
--- a/xen/common/rangeset.c Thu Dec 29 16:53:22 2005
+++ b/xen/common/rangeset.c Thu Dec 29 17:16:01 2005
@@ -28,7 +28,7 @@
/* Pretty-printing name. */
char name[32];

- /* RANGESETF_??? */
+ /* RANGESETF flags. */
unsigned int flags;
};

@@ -46,6 +46,24 @@
}

return x;
+}
+
+/* Return the lowest range in the set r, or NULL if r is empty. */
+static struct range *first_range(
+ struct rangeset *r)
+{
+ if ( list_empty(&r->range_list) )
+ return NULL;
+ return list_entry(r->range_list.next, struct range, list);
+}
+
+/* Return range following x in ascending order, or NULL if x is the highest. */
+static struct range *next_range(
+ struct rangeset *r, struct range *x)
+{
+ if ( x->list.next == &r->range_list )
+ return NULL;
+ return list_entry(x->list.next, struct range, list);
}

/* Remove a range from its list and free it. */
@@ -91,12 +109,12 @@
{
if ( x == NULL )
{
- x = list_entry(r->range_list.next, struct range, list);
+ x = first_range(r);
x->s = s;
}
else if ( (x->e < s) && ((x->e + 1) != s) )
{
- x = list_entry(x->list.next, struct range, list);
+ x = next_range(r, x);
x->s = s;
}

@@ -104,15 +122,15 @@

for ( ; ; )
{
- y = list_entry(x->list.next, struct range, list);
- if ( (x->list.next == &r->range_list) || (y->e > x->e) )
+ y = next_range(r, x);
+ if ( (y == NULL) || (y->e > x->e) )
break;
destroy_range(y);
}
}

- y = list_entry(x->list.next, struct range, list);
- if ( (x->list.next != &r->range_list) && ((x->e + 1) == y->s) )
+ y = next_range(r, x);
+ if ( (y != NULL) && ((x->e + 1) == y->s) )
{
x->e = y->e;
destroy_range(y);
@@ -162,18 +180,18 @@
else
{
if ( x == NULL )
- x = list_entry(r->range_list.next, struct range, list);
+ x = first_range(r);

if ( x->s < s )
{
x->e = s - 1;
- x = list_entry(x->list.next, struct range, list);
+ x = next_range(r, x);
}

while ( x != y )
{
t = x;
- x = list_entry(x->list.next, struct range, list);
+ x = next_range(r, x);
destroy_range(t);
}

@@ -257,6 +275,8 @@
void rangeset_destroy(
struct rangeset *r)
{
+ struct range *x;
+
if ( r == NULL )
return;

@@ -267,11 +287,8 @@
spin_unlock(&r->domain->rangesets_lock);
}

- while ( !list_empty(&r->range_list) )
- {
- struct range *x = list_entry(r->range_list.next, struct range, list);
+ while ( (x = first_range(r)) != NULL )
destroy_range(x);
- }

xfree(r);
}

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