kingst-la2016: rephrase sample data to session feed logic

Comment on the layout of the incoming captured data for awareness during
maintenance. Rephrase the send_chunk() routine for improved readability.
Eliminate too short i, j, k variables. Comment on the non-obvious flush
condition for the conversion buffer. Prefer "sample" in variable names
to not confuse captures with the device's run state. Eliminate another
literal 2 which slipped through in an earlier commit. Adjust data types.

diff --git a/src/hardware/kingst-la2016/protocol.c b/src/hardware/kingst-la2016/protocol.c
index d42ea8ab51b1de4941c7950247cdb76afbd58611..fb7703f73e88e94aad6fb1ad0988dbfcc0ac33d6 100644 (file)
--- a/src/hardware/kingst-la2016/protocol.c
+++ b/src/hardware/kingst-la2016/protocol.c
@@ -970,20 +970,25 @@ static int la2016_start_download(const struct sr_dev_inst *sdi,
        return SR_OK;
 }
 
+/*
+ * A chunk (received via USB) contains a number of transfers (USB length
+ * divided by 16) which contain a number of packets (5 per transfer) which
+ * contain a number of samples (8bit repeat count per 16bit sample data).
+ */
 static void send_chunk(struct sr_dev_inst *sdi,
-       const uint8_t *packets, unsigned int num_tfers)
+       const uint8_t *packets, size_t num_xfers)
 {
        struct dev_context *devc;
        struct sr_datafeed_logic logic;
        struct sr_datafeed_packet sr_packet;
        unsigned int max_samples, n_samples, total_samples, free_n_samples;
-       unsigned int i, j, k;
+       size_t num_pkts;
        gboolean do_signal_trigger;
        uint8_t *wp;
        const uint8_t *rp;
-       uint16_t state;
-       uint8_t repetitions;
-       uint8_t sample_buff[sizeof(state)];
+       uint16_t sample_value;
+       size_t repetitions;
+       uint8_t sample_buff[sizeof(sample_value)];
 
        devc = sdi->priv;
 
@@ -1005,11 +1010,18 @@ static void send_chunk(struct sr_dev_inst *sdi,
        }
 
        rp = packets;
-       for (i = 0; i < num_tfers; i++) {
-               for (k = 0; k < NUM_PACKETS_IN_CHUNK; k++) {
+       while (num_xfers--) {
+               num_pkts = NUM_PACKETS_IN_CHUNK;
+               while (num_pkts--) {
+                       /*
+                        * Flush the conversion buffer when a trigger
+                        * location needs to get communicated, or when
+                        * an to-get-expected sample repetition count
+                        * would no longer fit into the buffer.
+                        */
                        free_n_samples = max_samples - n_samples;
                        if (free_n_samples < 256 || do_signal_trigger) {
-                               logic.length = n_samples * 2;
+                               logic.length = n_samples * sizeof(sample_buff);;
                                sr_session_send(sdi, &sr_packet);
                                n_samples = 0;
                                wp = devc->convbuffer;
@@ -1019,17 +1031,19 @@ static void send_chunk(struct sr_dev_inst *sdi,
                                }
                        }
 
-                       state = read_u16le_inc(&rp);
+                       sample_value = read_u16le_inc(&rp);
                        repetitions = read_u8_inc(&rp);
-                       write_u16le((void *)&sample_buff, state);
-                       for (j = 0; j < repetitions; j++) {
-                               memcpy(wp, sample_buff, logic.unitsize);
-                               wp += logic.unitsize;
-                       }
 
                        n_samples += repetitions;
                        total_samples += repetitions;
                        devc->total_samples += repetitions;
+
+                       write_u16le(sample_buff, sample_value);
+                       while (repetitions--) {
+                               memcpy(wp, sample_buff, logic.unitsize);
+                               wp += logic.unitsize;
+                       }
+
                        if (devc->trigger_involved && !devc->trigger_marked) {
                                if (!--devc->n_reps_until_trigger) {
                                        devc->trigger_marked = TRUE;

diff --git a/src/hardware/kingst-la2016/protocol.h b/src/hardware/kingst-la2016/protocol.h
index 353176d3751fd18006a6a1fa382452e026601ea0..b0dc3d04845912d2f28535dd88cfb4fb218bb7a6 100644 (file)
--- a/src/hardware/kingst-la2016/protocol.h
+++ b/src/hardware/kingst-la2016/protocol.h
@@ -122,14 +122,14 @@ struct dev_context {
        gboolean completion_seen;
        gboolean download_finished;
        struct capture_info info;
-       unsigned int n_transfer_packets_to_read; /* each with 5 acq packets */
-       unsigned int n_bytes_to_read;
-       unsigned int n_reps_until_trigger;
+       uint32_t n_transfer_packets_to_read; /* each with 5 acq packets */
+       uint32_t n_bytes_to_read;
+       uint32_t n_reps_until_trigger;
        gboolean trigger_marked;
        uint64_t total_samples;
        uint32_t read_pos;
 
-       unsigned int convbuffer_size;
+       size_t convbuffer_size;
        uint8_t *convbuffer;
        struct libusb_transfer *transfer;
 };