sr: add voltage parser and prettyprinter

diff --git a/sigrok-proto.h b/sigrok-proto.h
index d5a9adb9373067aa9b7028ce123bc5d14379ba42..ed6dd8d87ecdef69703e54ecbf61ccac0055d9c7 100644 (file)
--- a/sigrok-proto.h
+++ b/sigrok-proto.h
@@ -114,12 +114,14 @@ SR_API struct sr_output_format **sr_output_list(void);
 
 SR_API char *sr_samplerate_string(uint64_t samplerate);
 SR_API char *sr_period_string(uint64_t frequency);
+SR_API char *sr_voltage_string(struct sr_rational *voltage);
 SR_API char **sr_parse_triggerstring(struct sr_dev *dev,
                                     const char *triggerstring);
 SR_API int sr_parse_sizestring(const char *sizestring, uint64_t *size);
 SR_API uint64_t sr_parse_timestring(const char *timestring);
 SR_API gboolean sr_parse_boolstring(const char *boolstring);
 SR_API int sr_parse_period(const char *periodstr, struct sr_rational *r);
+SR_API int sr_parse_voltage(const char *voltstr, struct sr_rational *r);
 
 /*--- version.c -------------------------------------------------------------*/
 

diff --git a/strutil.c b/strutil.c
index ea69a2af628b43a6be95c7977863336fbe5da3c1..26296cea21419aee00f784e18fbefcf02b2a55be 100644 (file)
--- a/strutil.c
+++ b/strutil.c
@@ -110,6 +110,45 @@ SR_API char *sr_period_string(uint64_t frequency)
        return o;
 }
 
+/**
+ * Convert a numeric frequency value to the "natural" string representation
+ * of its voltage value.
+ *
+ * E.g. a value of 300000 would be converted to "300mV", 2 to "2V".
+ *
+ * @param voltage The voltage represented as a rational number, with the
+ *                denominator a divisor of 1V.
+ *
+ * @return A g_try_malloc()ed string representation of the voltage value,
+ *         or NULL upon errors. The caller is responsible to g_free() the
+ *         memory.
+ */
+SR_API char *sr_voltage_string(struct sr_rational *voltage)
+{
+       char *o;
+       int r;
+
+       if (!(o = g_try_malloc0(30 + 1))) {
+               sr_err("strutil: %s: o malloc failed", __func__);
+               return NULL;
+       }
+
+       if (voltage->q == 1000)
+               r = snprintf(o, 30, "%" PRIu64 "mV", voltage->p);
+       else if (voltage->q == 1)
+               r = snprintf(o, 30, "%" PRIu64 "V", voltage->p);
+       else
+               r = -1;
+
+       if (r < 0) {
+               /* Something went wrong... */
+               g_free(o);
+               return NULL;
+       }
+
+       return o;
+}
+
 /**
  * Parse a trigger specification string.
  *
@@ -344,3 +383,28 @@ SR_API int sr_parse_period(const char *periodstr, struct sr_rational *r)
 }
 
 
+SR_API int sr_parse_voltage(const char *voltstr, struct sr_rational *r)
+{
+       char *s;
+
+       r->p = strtoull(voltstr, &s, 10);
+       if (r->p == 0 && s == voltstr)
+               /* No digits found. */
+               return SR_ERR_ARG;
+
+       if (s && *s) {
+               while (*s == ' ')
+                       s++;
+               if (!strcasecmp(s, "mv"))
+                       r->q = 1000L;
+               else if (!strcasecmp(s, "v"))
+                       r->q = 1;
+               else
+                       /* Must have a base suffix. */
+                       return SR_ERR_ARG;
+       }
+
+       return SR_OK;
+}
+
+