Add and use std_session_send_df_header().

[libsigrok.git] / std.c

diff --git a/std.c b/std.c
index a9cbec0eaa367134b85b56572e7ba0b755a711cf..d436436cf6b77e03be31b4c0a5f8dc0298e2731c 100644 (file)
--- a/std.c
+++ b/std.c
@@ -57,3 +57,45 @@ SR_PRIV int std_hw_init(struct sr_context *sr_ctx, struct sr_dev_driver *di,
 
        return SR_OK;
 }
+
+/**
+ * Standard API helper for sending an SR_DF_HEADER packet.
+ *
+ * This function can be used to simplify most driver's
+ * hw_dev_acquisition_start() API callback.
+ *
+ * @param sdi The device instance to use.
+ * @param prefix A driver-specific prefix string used for log messages.
+ *              Must not be NULL. An empty string is allowed.
+ *
+ * @return SR_OK upon success, SR_ERR_ARG upon invalid arguments, or
+ *         SR_ERR upon other errors.
+ */
+SR_PRIV int std_session_send_df_header(const struct sr_dev_inst *sdi,
+                                      const char *prefix)
+{
+       int ret;
+       struct sr_datafeed_packet packet;
+       struct sr_datafeed_header header;
+
+       if (!prefix) {
+               sr_err("Invalid prefix.");
+               return SR_ERR_ARG;
+       }
+
+       sr_dbg("%sStarting acquisition.", prefix);
+
+       /* Send header packet to the session bus. */
+       sr_dbg("%sSending SR_DF_HEADER packet.", prefix);
+       packet.type = SR_DF_HEADER;
+       packet.payload = (uint8_t *)&header;
+       header.feed_version = 1;
+       gettimeofday(&header.starttime, NULL);
+
+       if ((ret = sr_session_send(sdi, &packet)) < 0) {
+               sr_err("%sFailed to send header packet: %d.", prefix, ret);
+               return ret;
+       }
+
+       return SR_OK;
+}