Non-copying interface to BIO pairs.
It's still totally untested ...
diff --git a/crypto/bio/bss_bio.c b/crypto/bio/bss_bio.c
index 562e9d8..ad80794 100644
--- a/crypto/bio/bss_bio.c
+++ b/crypto/bio/bss_bio.c
@@ -13,6 +13,7 @@
#endif
#include <assert.h>
+#include <limits.h>
#include <stdlib.h>
#include <string.h>
@@ -195,6 +196,82 @@
return size;
}
+/* 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 totally untested as of yet --
+ * I wrote it, but have not yet read it; and surely it still is full
+ * of bugs. */
+static size_t bio_nread0(BIO *bio, char **buf)
+ {
+ struct bio_bio_st *b, *peer_b;
+ size_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, num); /* 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 size_t bio_nread(BIO *bio, char **buf, size_t num)
+ {
+ struct bio_bio_st *b, *peer_b;
+ size_t available;
+
+ 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, char *buf, int num_)
{
size_t num = num_;
@@ -268,6 +345,76 @@
return num;
}
+/* non-copying interface: provide pointer to region to write to
+ * bio_nwrite0: check how much space is available
+ * bio_nwrite: also increase length
+ * (example usage: bio_nwrite0(), write to buffer, bio_nwrite()
+ * or just bio_nwrite(), write to buffer)
+ */
+static size_t bio_nwrite0(BIO *bio, char **buf)
+ {
+ struct bio_bio_st *b;
+ size_t num;
+ size_t write_offset;
+
+ BIO_clear_retry_flags(bio);
+
+ if (!bio->init)
+ return 0;
+
+ b = bio->ptr;
+ assert(b != NULL);
+ assert(b->peer != NULL);
+ assert(b->buf != NULL);
+
+ b->request = 0;
+ if (b->closed)
+ {
+ BIOerr(BIO_F_BIO_NWRITE0, BIO_R_BROKEN_PIPE);
+ return -1;
+ }
+
+ assert(b->len <= b->size);
+
+ if (b->len == b->size)
+ {
+ BIO_set_retry_write(bio);
+ return -1;
+ }
+
+ num = b->size - b->len;
+ write_offset = b->offset + b->len;
+ if (write_offset >= b->size)
+ write_offset -= b->size;
+ if (write_offset + num > b->size)
+ /* no ring buffer wrap-around for non-copying interface
+ * (to fulfil the promise by BIO_ctrl_get_write_guarantee,
+ * BIO_nwrite may have to be called twice) */
+ num = b->size - write_offset;
+
+ if (buf != NULL)
+ *buf = b->buf + write_offset;
+ assert(write_offset + num <= b->size);
+
+ return num;
+ }
+
+static size_t bio_nwrite(BIO *bio, char **buf, size_t num)
+ {
+ struct bio_bio_st *b;
+ size_t space;
+
+ space = bio_nwrite0(bio, buf);
+ if (num > space)
+ num = space;
+ if (num <= 0)
+ return num;
+ b->len += num;
+ assert(b->len <= b->size);
+
+ return num;
+ }
+
static long bio_ctrl(BIO *bio, int cmd, long num, void *ptr)
{
@@ -351,6 +498,21 @@
ret = 1;
break;
+ case BIO_C_NREAD:
+ /* non-copying read */
+ ret = (long) bio_nread(bio, ptr, (size_t) num);
+ break;
+
+ case BIO_C_NWRITE0:
+ /* prepare for non-copying write */
+ ret = (long) bio_nwrite0(bio, ptr);
+ break;
+
+ case BIO_C_NWRITE:
+ /* non-copying write */
+ ret = (long) bio_nwrite(bio, ptr, (size_t) num);
+ break;
+
/* standard CTRL codes follow */
@@ -586,3 +748,73 @@
{
return BIO_ctrl(bio, BIO_C_GET_READ_REQUEST, 0, NULL);
}
+
+
+/* BIO_nread0/nread/nwrite0/nwrite are availabe only for BIO pairs for now
+ * (conceivably some other BIOs could allow non-copying reads and writes too.)
+ */
+int BIO_nread0(BIO *bio, char **buf)
+ {
+ long ret;
+
+ if (!bio->init)
+ {
+ BIOerr(BIO_F_BIO_NREAD0, BIO_R_UNINITIALIZED);
+ return -2;
+ }
+
+ ret = BIO_ctrl(bio, BIO_C_NREAD0, 0, buf);
+ if (ret > INT_MAX)
+ return INT_MAX;
+ else
+ return (int) ret;
+ }
+
+int BIO_nread(BIO *bio, char **buf, int num)
+ {
+ int ret;
+
+ if (!bio->init)
+ {
+ BIOerr(BIO_F_BIO_NREAD, BIO_R_UNINITIALIZED);
+ return -2;
+ }
+
+ ret = (int) BIO_ctrl(bio, BIO_C_NREAD, num, buf);
+ if (ret > 0)
+ bio->num_read += ret;
+ return ret;
+ }
+
+int BIO_nwrite0(BIO *bio, char **buf)
+ {
+ long ret;
+
+ if (!bio->init)
+ {
+ BIOerr(BIO_F_BIO_NWRITE0, BIO_R_UNINITIALIZED);
+ return -2;
+ }
+
+ ret = BIO_ctrl(bio, BIO_C_NWRITE0, 0, buf);
+ if (ret > INT_MAX)
+ return INT_MAX;
+ else
+ return (int) ret;
+ }
+
+int BIO_nwrite(BIO *bio, char **buf, int num)
+ {
+ int ret;
+
+ if (!bio->init)
+ {
+ BIOerr(BIO_F_BIO_NWRITE, BIO_R_UNINITIALIZED);
+ return -2;
+ }
+
+ ret = BIO_ctrl(bio, BIO_C_NWRITE, num, buf);
+ if (ret > 0)
+ bio->num_read += ret;
+ return ret;
+ }
