+/* non-copying interface: provide pointer to available data in buffer
+ * bio_nread0: return number of available bytes
+ * bio_nread: also advance index
+ * (example usage: bio_nread0(), read from buffer, bio_nread()
+ * or just bio_nread(), read from buffer)
+ */
+/* WARNING: The non-copying interface is largely untested as of yet
+ * and may contain bugs. */
+static ssize_t bio_nread0(BIO *bio, char **buf)
+ {
+ struct bio_bio_st *b, *peer_b;
+ ssize_t num;
+
+ BIO_clear_retry_flags(bio);
+
+ if (!bio->init)
+ return 0;
+
+ b = bio->ptr;
+ assert(b != NULL);
+ assert(b->peer != NULL);
+ peer_b = b->peer->ptr;
+ assert(peer_b != NULL);
+ assert(peer_b->buf != NULL);
+
+ peer_b->request = 0;
+
+ if (peer_b->len == 0)
+ {
+ char dummy;
+
+ /* avoid code duplication -- nothing available for reading */
+ return bio_read(bio, &dummy, 1); /* returns 0 or -1 */
+ }
+
+ num = peer_b->len;
+ if (peer_b->size < peer_b->offset + num)
+ /* no ring buffer wrap-around for non-copying interface */
+ num = peer_b->size - peer_b->offset;
+ assert(num > 0);
+
+ if (buf != NULL)
+ *buf = peer_b->buf + peer_b->offset;
+ return num;
+ }
+
+static ssize_t bio_nread(BIO *bio, char **buf, size_t num_)
+ {
+ struct bio_bio_st *b, *peer_b;
+ ssize_t num, available;
+
+ if (num_ > SSIZE_MAX)
+ num = SSIZE_MAX;
+ else
+ num = (ssize_t)num_;
+
+ available = bio_nread0(bio, buf);
+ if (num > available)
+ num = available;
+ if (num <= 0)
+ return num;
+
+ b = bio->ptr;
+ peer_b = b->peer->ptr;
+
+ peer_b->len -= num;
+ if (peer_b->len)
+ {
+ peer_b->offset += num;
+ assert(peer_b->offset <= peer_b->size);
+ if (peer_b->offset == peer_b->size)
+ peer_b->offset = 0;
+ }
+ else
+ peer_b->offset = 0;
+
+ return num;
+ }
+
+
+static int bio_write(BIO *bio, const char *buf, int num_)