demo: Properly handle low samplerates

[libsigrok.git] / src / hardware / demo / protocol.c

diff --git a/src/hardware/demo/protocol.c b/src/hardware/demo/protocol.c
index 8b89d3548f8ce0fd3fb88ccb25c38733fc6deb1d..46808fd6cf5622b4cd2ad333906ab9159059ac3d 100644 (file)
--- a/src/hardware/demo/protocol.c
+++ b/src/hardware/demo/protocol.c
@@ -273,9 +273,8 @@ static void logic_generator(struct sr_dev_inst *sdi, uint64_t size)
                break;
        case PATTERN_INC:
                for (i = 0; i < size; i++) {
-                       for (j = 0; j < devc->logic_unitsize; j++) {
+                       for (j = 0; j < devc->logic_unitsize; j++)
                                devc->logic_data[i + j] = devc->step;
-                       }
                        devc->step++;
                }
                break;
@@ -460,12 +459,24 @@ SR_PRIV int demo_prepare_data(int fd, int revents, void *cb_data)
        /* How many samples are outstanding since the last round? */
        samples_todo = (todo_us * devc->cur_samplerate + G_USEC_PER_SEC - 1)
                        / G_USEC_PER_SEC;
+
        if (devc->limit_samples > 0) {
                if (devc->limit_samples < devc->sent_samples)
                        samples_todo = 0;
                else if (devc->limit_samples - devc->sent_samples < samples_todo)
                        samples_todo = devc->limit_samples - devc->sent_samples;
        }
+
+       if (samples_todo == 0)
+               return G_SOURCE_CONTINUE;
+
+#if (SAMPLES_PER_FRAME > 0) /* Avoid "comparison < 0 always false" warning. */
+       /* Never send more samples than a frame can fit... */
+       samples_todo = MIN(samples_todo, SAMPLES_PER_FRAME);
+       /* ...or than we need to finish the current frame. */
+       samples_todo = MIN(samples_todo, SAMPLES_PER_FRAME - devc->sent_frame_samples);
+#endif
+
        /* Calculate the actual time covered by this run back from the sample
         * count, rounded towards zero. This avoids getting stuck on a too-low
         * time delta with no samples being sent due to round-off.
@@ -516,8 +527,16 @@ SR_PRIV int demo_prepare_data(int fd, int revents, void *cb_data)
                return G_SOURCE_REMOVE;
        }
        devc->sent_samples += samples_todo;
+       devc->sent_frame_samples += samples_todo;
        devc->spent_us += todo_us;
 
+#if (SAMPLES_PER_FRAME > 0) /* Avoid "comparison >= 0 always true" warning. */
+       if (devc->sent_frame_samples >= SAMPLES_PER_FRAME) {
+               std_session_send_frame_end(sdi);
+               devc->sent_frame_samples = 0;
+       }
+#endif
+
        if ((devc->limit_samples > 0 && devc->sent_samples >= devc->limit_samples)
                        || (limit_us > 0 && devc->spent_us >= limit_us)) {
 
@@ -535,6 +554,11 @@ SR_PRIV int demo_prepare_data(int fd, int revents, void *cb_data)
                }
                sr_dbg("Requested number of samples reached.");
                sr_dev_acquisition_stop(sdi);
+       } else {
+#if (SAMPLES_PER_FRAME > 0)
+               if (devc->sent_frame_samples == 0)
+                       std_session_send_frame_begin(sdi);
+#endif
        }
 
        return G_SOURCE_CONTINUE;