sr_scpi_free(): Allow NULL as argument.

[libsigrok.git] / src / strutil.c

diff --git a/src/strutil.c b/src/strutil.c
index fc6c7580553555a8b76c7e1126e719ea38aa4220..72378d4a2942d5dd7f411e35d41ffb7a01b9a183 100644 (file)
--- a/src/strutil.c
+++ b/src/strutil.c
@@ -347,35 +347,53 @@ SR_API char *sr_samplerate_string(uint64_t samplerate)
 }
 
 /**
- * Convert a numeric frequency value to the "natural" string representation
- * of its period.
+ * Convert a numeric period value to the "natural" string representation
+ * of its period value.
  *
- * E.g. a value of 3000000 would be converted to "3 us", 20000 to "50 ms".
+ * The period is specified as a rational number's numerator and denominator.
  *
- * @param frequency The frequency in Hz.
+ * E.g. a pair of (1, 5) would be converted to "200 ms", (10, 100) to "100 ms".
  *
- * @return A newly allocated string representation of the frequency value,
+ * @param v_p The period numerator.
+ * @param v_q The period denominator.
+ *
+ * @return A newly allocated string representation of the period value,
  *         or NULL upon errors. The caller is responsible to g_free() the
  *         memory.
  *
- * @since 0.1.0
+ * @since 0.5.0
  */
-SR_API char *sr_period_string(uint64_t frequency)
+SR_API char *sr_period_string(uint64_t v_p, uint64_t v_q)
 {
+       double freq, v;
        char *o;
-       int r;
+       int prec, r;
+
+       freq = 1 / ((double)v_p / v_q);
 
-       /* Allocate enough for a uint64_t as string + " ms". */
        o = g_malloc0(30 + 1);
 
-       if (frequency >= SR_GHZ(1))
-               r = snprintf(o, 30, "%" PRIu64 " ns", frequency / 1000000000);
-       else if (frequency >= SR_MHZ(1))
-               r = snprintf(o, 30, "%" PRIu64 " us", frequency / 1000000);
-       else if (frequency >= SR_KHZ(1))
-               r = snprintf(o, 30, "%" PRIu64 " ms", frequency / 1000);
-       else
-               r = snprintf(o, 30, "%" PRIu64 " s", frequency);
+       if (freq > SR_GHZ(1)) {
+               v = (double)v_p / v_q * 1000000000000.0;
+               prec = ((v - (uint64_t)v) < FLT_MIN) ? 0 : 3;
+               r = snprintf(o, 30, "%.*f ps", prec, v);
+       } else if (freq > SR_MHZ(1)) {
+               v = (double)v_p / v_q * 1000000000.0;
+               prec = ((v - (uint64_t)v) < FLT_MIN) ? 0 : 3;
+               r = snprintf(o, 30, "%.*f ns", prec, v);
+       } else if (freq > SR_KHZ(1)) {
+               v = (double)v_p / v_q * 1000000.0;
+               prec = ((v - (uint64_t)v) < FLT_MIN) ? 0 : 3;
+               r = snprintf(o, 30, "%.*f us", prec, v);
+       } else if (freq > 1) {
+               v = (double)v_p / v_q * 1000.0;
+               prec = ((v - (uint64_t)v) < FLT_MIN) ? 0 : 3;
+               r = snprintf(o, 30, "%.*f ms", prec, v);
+       } else {
+               v = (double)v_p / v_q;
+               prec = ((v - (uint64_t)v) < FLT_MIN) ? 0 : 3;
+               r = snprintf(o, 30, "%.*f s", prec, v);
+       }
 
        if (r < 0) {
                /* Something went wrong... */