emulate legacy ISO reception API on top of new rawiso API

git-svn-id: svn://svn.linux1394.org/libraw1394/trunk@99 53a565d1-3bb7-0310-b661-cf11e63c67ab

1 files changed, 158 insertions, 0 deletions

diff --git a/src/iso-legacy.c b/src/iso-legacy.c
new file mode 100644
index 0000000..91a6484
--- /dev/null
+++ b/src/iso-legacy.c
@@ -0,0 +1,158 @@
+/*
+ * libraw1394 - library for raw access to the 1394 bus with the Linux subsystem.
+ *
+ * Copyright (C) 1999,2000,2001,2002 Andreas Bombe
+ *        new ISO API by Dan Maas
+ *
+ * This library is licensed under the GNU Lesser General Public License (LGPL),
+ * version 2.1 or later. See the file COPYING.LIB in the distribution for
+ * details.
+ */
+
+#include <config.h>
+#include <errno.h>
+#include <unistd.h>
+#include <byteswap.h>
+
+#include "raw1394.h"
+#include "kernel-raw1394.h"
+#include "raw1394_private.h"
+
+/* legacy ISO API - emulated for backwards compatibility
+ *
+ * (this code emulates the behavior of the old API using
+ * the new "rawiso" API)
+ */
+
+static enum raw1394_iso_disposition legacy_iso_handler(raw1394handle_t handle,
+						       unsigned char *data,
+						       unsigned int len,
+						       unsigned char channel,
+						       unsigned char tag,
+						       unsigned char sy,
+						       unsigned int cycle,
+						       unsigned int dropped);
+
+/**
+ * raw1394_set_iso_handler - set isochronous packet handler
+ * @new_h: pointer to new handler
+ *
+ * Sets the handler to be called when an isochronous packet is received to
+ * @new_h and returns the old handler.  The default handler does nothing.
+ *
+ * In order to actually get iso packet events, receiving on a specific channel
+ * first has to be enabled with raw1394_start_iso_rcv() and can be stopped again
+ * with raw1394_stop_iso_rcv().
+ **/
+iso_handler_t raw1394_set_iso_handler(struct raw1394_handle *handle,
+                                      unsigned int channel, iso_handler_t new)
+{
+        if (channel >= 64)
+		goto err;
+
+	/* is this channel already being used? */
+	if (handle->iso_handler[channel] != NULL)
+		goto err;
+	  
+	/* start up the recv context, if necessary */
+	if (!handle->legacy_iso_active) {
+		/* hmm, is there a good average value for max_packet_size? */
+		if (raw1394_iso_multichannel_recv_init(handle,
+						      legacy_iso_handler,
+						      1024,
+						      500,
+						      -1))
+			goto err;
+
+		if (raw1394_iso_recv_start(handle, -1)) {
+			raw1394_iso_shutdown(handle);
+			goto err;
+		}
+
+		handle->legacy_iso_active = 1;
+	}
+	
+        if (new == NULL) {
+                iso_handler_t old = handle->iso_handler[channel];
+                handle->iso_handler[channel] = NULL;
+                return old;
+        } else {
+		handle->iso_handler[channel] = new;
+		return NULL;
+	}
+
+err:
+	return (iso_handler_t)-1;
+}
+
+/**
+ * raw1394_start_iso_rcv - enable isochronous receiving
+ * @channel: channel number to start receiving on
+ *
+ * Enables the reception of isochronous packets in @channel on @handle.
+ * Isochronous packets are then passed to the callback specified with
+ * raw1394_set_iso_handler().
+ **/
+int raw1394_start_iso_rcv(struct raw1394_handle *handle, unsigned int channel)
+{
+	if (!handle->legacy_iso_active || channel > 63) {
+                errno = EINVAL;
+                return -1;
+        }
+
+	return raw1394_iso_recv_listen_channel(handle, channel);
+}
+
+/**
+ * raw1394_stop_iso_rcv - stop isochronous receiving
+ * @channel: channel to stop receiving on
+ *
+ * Stops the reception of isochronous packets in @channel on @handle.
+ **/
+int raw1394_stop_iso_rcv(struct raw1394_handle *handle, unsigned int channel)
+{
+	if (!handle->legacy_iso_active || channel > 63) {
+                errno = EINVAL;
+                return -1;
+        }
+
+	return raw1394_iso_recv_unlisten_channel(handle, channel);
+}
+
+static enum raw1394_iso_disposition legacy_iso_handler(raw1394handle_t handle,
+						       unsigned char *data,
+						       unsigned int len,
+						       unsigned char channel,
+						       unsigned char tag,
+						       unsigned char sy,
+						       unsigned int cycle,
+						       unsigned int dropped)
+{
+	size_t length;
+	quadlet_t *buf;
+
+	if (!handle->iso_handler[channel])
+		return RAW1394_ISO_OK;
+
+	length = len;
+	buf = (quadlet_t*) data;
+
+	/* back up one quadlet to get the ISO header */
+	/* (note: we assume the card is keeping ISO headers!) */
+	buf -= 1;
+	length += 4;
+
+	/* pad length to quadlet boundary */
+	if (length % 4)
+		length += 4 - (length%4);
+
+	/* make the ISO header big-endian, regardless of host byte order */
+#ifndef WORDS_BIGENDIAN
+	buf[0] = bswap_32(buf[0]);
+#endif
+
+	if (handle->iso_handler[channel](handle, channel, length, buf))
+		return RAW1394_ISO_ERROR;
+
+	return RAW1394_ISO_OK;
+}