move iso.c to transfer.c, as it's used for all transfers.

move transfer callback to transfer.go.

usb/transfer.c

@@ -0,0 +1,107 @@
+// Copyright 2013 Google Inc.  All rights reserved.
+// Copyright 2016 the gousb Authors.  All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <libusb-1.0/libusb.h>
+#include <stdio.h>
+#include <string.h>
+
+void print_xfer(struct libusb_transfer *xfer);
+void xfer_callback(void *);
+
+void callback(struct libusb_transfer *xfer) {
+	xfer_callback(xfer->user_data);
+}
+
+int submit(struct libusb_transfer *xfer) {
+	xfer->callback = &callback;
+	xfer->status = -1;
+	return libusb_submit_transfer(xfer);
+}
+
+void print_xfer(struct libusb_transfer *xfer) {
+	int i;
+
+	printf("Transfer:\n");
+	printf("  dev_handle:   %p\n", xfer->dev_handle);
+	printf("  flags:        %08x\n", xfer->flags);
+	printf("  endpoint:     %x\n", xfer->endpoint);
+	printf("  type:         %x\n", xfer->type);
+	printf("  timeout:      %dms\n", xfer->timeout);
+	printf("  status:       %x\n", xfer->status);
+	printf("  length:       %d (act: %d)\n", xfer->length, xfer->actual_length);
+	printf("  callback:     %p\n", xfer->callback);
+	printf("  user_data:    %p\n", xfer->user_data);
+	printf("  buffer:       %p\n", xfer->buffer);
+	printf("  num_iso_pkts: %d\n", xfer->num_iso_packets);
+	printf("  packets:\n");
+	for (i = 0; i < xfer->num_iso_packets; i++) {
+		printf("    [%04d] %d (act: %d) %x\n", i,
+			xfer->iso_packet_desc[i].length,
+			xfer->iso_packet_desc[i].actual_length,
+			xfer->iso_packet_desc[i].status);
+	}
+}
+
+// extract data from a non-isochronous transfer.
+int extract_data(struct libusb_transfer *xfer, void *raw, int max, unsigned char *status) {
+	int i;
+	unsigned char *in = xfer->buffer;
+	unsigned char *out = raw;
+
+    int len = xfer->actual_length;
+    if (len > max) {
+            len = max;
+    }
+    memcpy(out, in, len);
+   	if (xfer->status != 0 && *status == 0) {
+            *status = xfer->status;
+   	}
+    return len;
+}
+
+// extract data from an isochronous transfer. Very similar to extract_data, but
+// acquires data from xfer->iso_packet_desc array instead of xfer attributes.
+int extract_iso_data(struct libusb_transfer *xfer, void *raw, int max, unsigned char *status) {
+	int i;
+	int copied = 0;
+	unsigned char *in = xfer->buffer;
+	unsigned char *out = raw;
+	for (i = 0; i < xfer->num_iso_packets; i++) {
+		struct libusb_iso_packet_descriptor pkt = xfer->iso_packet_desc[i];
+
+		// Copy the data
+		int len = pkt.actual_length;
+		if (copied + len > max) {
+			len = max - copied;
+		}
+		memcpy(out, in, len);
+		copied += len;
+
+		// Increment offsets
+		in += pkt.length;
+		out += len;
+
+        if (copied == max) {
+                break;
+        }
+
+		// Extract first error
+		if (pkt.status == 0 || *status != 0) {
+			continue;
+		}
+		*status = pkt.status;
+	}
+	return copied;
+}