sr_scpi_free(): Allow NULL as argument.

[libsigrok.git] / src / analog.c

diff --git a/src/analog.c b/src/analog.c
index e2966875c3bbfb8c55212b19cd9ec2a110163347..9bc88b310efd8aeb42333575562ce557d79c1fae 100644 (file)
--- a/src/analog.c
+++ b/src/analog.c
@@ -63,8 +63,8 @@ static struct unit_mq_string unit_strings[] = {
        { SR_UNIT_BOOLEAN, "" },
        { SR_UNIT_SECOND, "s" },
        { SR_UNIT_SIEMENS, "S" },
-       { SR_UNIT_DECIBEL_MW, "dBu" },
-       { SR_UNIT_DECIBEL_VOLT, "dBv" },
+       { SR_UNIT_DECIBEL_MW, "dBm" },
+       { SR_UNIT_DECIBEL_VOLT, "dBV" },
        { SR_UNIT_UNITLESS, "" },
        { SR_UNIT_DECIBEL_SPL, "dB" },
        { SR_UNIT_CONCENTRATION, "ppm" },
@@ -329,6 +329,48 @@ SR_API const char *sr_analog_si_prefix(float *value, int *digits)
        return prefixes[prefix + NEG_PREFIX_COUNT];
 }
 
+/**
+ * Check if a unit "accepts" an SI prefix.
+ *
+ * E.g. SR_UNIT_VOLT is SI prefix friendly while SR_UNIT_DECIBEL_MW or
+ * SR_UNIT_PERCENTAGE are not.
+ *
+ * @param[in] unit The unit to check for SI prefix "friendliness".
+ *
+ * @return TRUE if the unit "accept" an SI prefix.
+ *
+ * @since 0.5.0
+ */
+SR_API gboolean sr_analog_si_prefix_friendly(enum sr_unit unit)
+{
+       static const enum sr_unit prefix_friendly_units[] = {
+               SR_UNIT_VOLT,
+               SR_UNIT_AMPERE,
+               SR_UNIT_OHM,
+               SR_UNIT_FARAD,
+               SR_UNIT_KELVIN,
+               SR_UNIT_HERTZ,
+               SR_UNIT_SECOND,
+               SR_UNIT_SIEMENS,
+               SR_UNIT_VOLT_AMPERE,
+               SR_UNIT_WATT,
+               SR_UNIT_WATT_HOUR,
+               SR_UNIT_METER_SECOND,
+               SR_UNIT_HENRY,
+               SR_UNIT_GRAM
+       };
+       unsigned int i;
+
+       for (i = 0; i < ARRAY_SIZE(prefix_friendly_units); i++)
+               if (unit == prefix_friendly_units[i])
+                       break;
+
+       if (unit != prefix_friendly_units[i])
+               return FALSE;
+
+       return TRUE;
+}
+
 /**
  * Convert the unit/MQ/MQ flags in the analog struct to a string.
  *