kingst-la2016: unobfuscate "user specified threshold" reference

Use a symbolic name for the "user specified input threshold" item's
position in the set of choices. Stick with array size for the complete
list of items instead of hiding the size behind an unrelated name. This
improves readability of the config get/set/list routines. Trim a text
line length while we are here.

The single variable for several purposes (user specified value, and
fixed value derived from currently selected choice out of a premade
set) still looks suspicious, and is not addressed in this commit.

diff --git a/src/hardware/kingst-la2016/api.c b/src/hardware/kingst-la2016/api.c
index 53a6bb49d33483ca104b7134d22b4e48a5e8265a..4337bd0a879a4b63e4b1f059744d156762b28016 100644 (file)
--- a/src/hardware/kingst-la2016/api.c
+++ b/src/hardware/kingst-la2016/api.c
@@ -125,7 +125,7 @@ static const char *logic_threshold[] = {
        "USER",
 };
 
-#define MAX_NUM_LOGIC_THRESHOLD_ENTRIES ARRAY_SIZE(logic_threshold)
+#define LOGIC_THRESHOLD_IDX_USER       (ARRAY_SIZE(logic_threshold) - 1)
 
 static GSList *scan(struct sr_dev_driver *di, GSList *options)
 {
@@ -412,6 +412,7 @@ static int config_get(uint32_t key, GVariant **data,
        struct dev_context *devc;
        struct sr_usb_dev_inst *usb;
        double rounded;
+       const char *label;
 
        (void)cg;
 
@@ -447,7 +448,8 @@ static int config_get(uint32_t key, GVariant **data,
                *data = std_gvar_tuple_double(rounded, rounded + 0.1);
                return SR_OK;
        case SR_CONF_LOGIC_THRESHOLD:
-               *data = g_variant_new_string(logic_threshold[devc->threshold_voltage_idx]);
+               label = logic_threshold[devc->threshold_voltage_idx];
+               *data = g_variant_new_string(label);
                break;
        case SR_CONF_LOGIC_THRESHOLD_CUSTOM:
                *data = g_variant_new_double(devc->threshold_voltage);
@@ -484,14 +486,12 @@ static int config_set(uint32_t key, GVariant *data,
        case SR_CONF_VOLTAGE_THRESHOLD:
                g_variant_get(data, "(dd)", &low, &high);
                devc->threshold_voltage = (low + high) / 2.0;
-               devc->threshold_voltage_idx = MAX_NUM_LOGIC_THRESHOLD_ENTRIES - 1; /* USER */
+               devc->threshold_voltage_idx = LOGIC_THRESHOLD_IDX_USER;
                break;
        case SR_CONF_LOGIC_THRESHOLD: {
-               if ((idx = std_str_idx(data, logic_threshold, MAX_NUM_LOGIC_THRESHOLD_ENTRIES)) < 0)
+               if ((idx = std_str_idx(data, ARRAY_AND_SIZE(logic_threshold))) < 0)
                        return SR_ERR_ARG;
-               if (idx == MAX_NUM_LOGIC_THRESHOLD_ENTRIES - 1) {
-                       /* user threshold */
-               } else {
+               if (idx != LOGIC_THRESHOLD_IDX_USER) {
                        devc->threshold_voltage = logic_threshold_value[idx];
                }
                devc->threshold_voltage_idx = idx;
@@ -538,7 +538,7 @@ static int config_list(uint32_t key, GVariant **data,
                *data = std_gvar_array_i32(ARRAY_AND_SIZE(trigger_matches));
                break;
        case SR_CONF_LOGIC_THRESHOLD:
-               *data = g_variant_new_strv(logic_threshold, MAX_NUM_LOGIC_THRESHOLD_ENTRIES);
+               *data = g_variant_new_strv(ARRAY_AND_SIZE(logic_threshold));
                break;
        default:
                return SR_ERR_NA;