*
* These functions do not need to know the allocated size nor any such thing,
* it's the caller's job to know that and to build the relevant vector pair.
+ * See the vp_{ring,data,room}_to_{ring,data,room}() functions at the end for
+ * this.
*/
/* vp_isempty(): returns true if both areas are empty */
return vp_get_varint_ofs(&v1, &v2, ofs, vptr);
}
+
+/************************************************************/
+/* ring-buffer API */
+/* This is used to manipulate rings made of (head,tail) */
+/* It creates vectors for reading (data) and writing (room) */
+/************************************************************/
+
+/* build 2 vectors <v1> and <v2> corresponding to the available data in ring
+ * buffer of size <size>, starting at address <area>, with a head <head> and
+ * a tail <tail>. <v2> is non-empty only if the data wraps (i.e. tail<head).
+ */
+static inline void vp_ring_to_data(struct ist *v1, struct ist *v2, char *area, size_t size, size_t head, size_t tail)
+{
+ v1->ptr = area + head;
+ v1->len = ((head <= tail) ? tail : size) - head;
+ v2->ptr = area;
+ v2->len = (tail < head) ? tail : 0;
+}
+
+/* build 2 vectors <v1> and <v2> corresponding to the available room in ring
+ * buffer of size <size>, starting at address <area>, with a head <head> and
+ * a tail <tail>. <v2> is non-empty only if the room wraps (i.e. head>tail).
+ */
+static inline void vp_ring_to_room(struct ist *v1, struct ist *v2, char *area, size_t size, size_t head, size_t tail)
+{
+ v1->ptr = area + tail;
+ v1->len = ((tail <= head) ? head : size) - tail;
+ v2->ptr = area;
+ v2->len = (head < tail) ? head : 0;
+}
+
+/* Set a ring's <head> and <tail> according to the data area represented by the
+ * concatenation of <v1> and <v2> which must point to two adjacent areas within
+ * a ring buffer of <size> bytes starting at <area>. <v1>, if not empty, starts
+ * at the head and <v2>, if not empty, ends at the tail. If both vectors are of
+ * length zero, the ring is considered empty and both its head and tail will be
+ * reset.
+ */
+static inline void vp_data_to_ring(const struct ist v1, const struct ist v2, char *area, size_t size, size_t *head, size_t *tail)
+{
+ size_t ofs;
+
+ if (!v1.len && !v2.len) {
+ *head = *tail = 0;
+ return;
+ }
+
+ ofs = (v1.len ? v1.ptr : v2.ptr) - area;
+ if (ofs >= size)
+ ofs -= size;
+ *head = ofs;
+
+ ofs = (v2.len ? v2.ptr + v2.len : v1.ptr + v1.len) - area;
+ if (ofs >= size)
+ ofs -= size;
+ *tail = ofs;
+}
+
+/* Set a ring's <head> and <tail> according to the room area represented by the
+ * concatenation of <v1> and <v2> which must point to two adjacent areas within
+ * a ring buffer of <size> bytes starting at <area>. <v1>, if not empty, starts
+ * at the tail and <v2>, if not empty, ends at the head. If both vectors are of
+ * length zero, the ring is considered full and both its head and tail will be
+ * reset (which cannot be distinguished from empty). The caller must make sure
+ * not to fill a ring with this API.
+ */
+static inline void vp_room_to_ring(const struct ist v1, const struct ist v2, char *area, size_t size, size_t *head, size_t *tail)
+{
+ size_t ofs;
+
+ if (!v1.len && !v2.len) {
+ *head = *tail = 0;
+ return;
+ }
+
+ ofs = (v1.len ? v1.ptr : v2.ptr) - area;
+ if (ofs >= size)
+ ofs -= size;
+ *tail = ofs;
+
+ ofs = (v2.len ? v2.ptr + v2.len : v1.ptr + v1.len) - area;
+ if (ofs >= size)
+ ofs -= size;
+ *head = ofs;
+}
+
#endif /* _HAPROXY_VECPAIR_H */
/*
projects / thirdparty / haproxy.git / commitdiff
