analog.c: sr_analog_to_float(): Support for receiving double values.

[libsigrok.git] / src / analog.c

diff --git a/src/analog.c b/src/analog.c
index 9bc88b310efd8aeb42333575562ce557d79c1fae..4ec724cfde488a0ae4a37a5c2ab0f0b414264da8 100644 (file)
--- a/src/analog.c
+++ b/src/analog.c
@@ -88,6 +88,9 @@ static struct unit_mq_string unit_strings[] = {
        { SR_UNIT_MOMME, "momme" },
        { SR_UNIT_TOLA, "tola" },
        { SR_UNIT_PIECE, "pcs" },
+       { SR_UNIT_JOULE, "J" },
+       { SR_UNIT_COULOMB, "C" },
+       { SR_UNIT_AMPERE_HOUR, "Ah" },
        ALL_ZERO
 };
 
@@ -119,6 +122,7 @@ static struct unit_mq_string mq_strings[] = {
        ALL_ZERO
 };
 
+/** @private */
 SR_PRIV int sr_analog_init(struct sr_datafeed_analog *analog,
                struct sr_analog_encoding *encoding,
                struct sr_analog_meaning *meaning,
@@ -173,9 +177,11 @@ SR_PRIV int sr_analog_init(struct sr_datafeed_analog *analog,
 SR_API int sr_analog_to_float(const struct sr_datafeed_analog *analog,
                float *outbuf)
 {
-       float offset;
-       unsigned int b, i, count;
+       unsigned int b, count;
        gboolean bigendian;
+       uint8_t conv_buf[sizeof(double)];
+       float *conv_f = (float*)conv_buf;
+       double *conv_d = (double*)conv_buf;
 
        if (!analog || !(analog->data) || !(analog->meaning)
                        || !(analog->encoding) || !outbuf)
@@ -274,20 +280,39 @@ SR_API int sr_analog_to_float(const struct sr_datafeed_analog *analog,
                /* The data is already in the right format. */
                memcpy(outbuf, analog->data, count * sizeof(float));
        } else {
-               for (i = 0; i < count; i += analog->encoding->unitsize) {
+               for (unsigned int i = 0; i < count; i++) {
                        for (b = 0; b < analog->encoding->unitsize; b++) {
                                if (analog->encoding->is_bigendian == bigendian)
-                                       ((uint8_t *)outbuf)[i + b] =
+                                       conv_buf[b] =
                                                ((uint8_t *)analog->data)[i * analog->encoding->unitsize + b];
                                else
-                                       ((uint8_t *)outbuf)[i + (analog->encoding->unitsize - b)] =
+                                       conv_buf[analog->encoding->unitsize - b - 1] =
                                                ((uint8_t *)analog->data)[i * analog->encoding->unitsize + b];
                        }
-                       if (analog->encoding->scale.p != 1
-                                       || analog->encoding->scale.q != 1)
-                               outbuf[i] = (outbuf[i] * analog->encoding->scale.p) / analog->encoding->scale.q;
-                       offset = ((float)analog->encoding->offset.p / (float)analog->encoding->offset.q);
-                       outbuf[i] += offset;
+
+                       if (analog->encoding->unitsize == sizeof(float)) {
+                               if (analog->encoding->scale.p != 1
+                                   || analog->encoding->scale.q != 1)
+                                       *conv_f = (*conv_f * analog->encoding->scale.p) / analog->encoding->scale.q;
+                               float offset = ((float)analog->encoding->offset.p / (float)analog->encoding->offset.q);
+                               *conv_f += offset;
+
+                               outbuf[i] = *conv_f;
+                       }
+                       else if (analog->encoding->unitsize == sizeof(double)) {
+                               if (analog->encoding->scale.p != 1
+                                   || analog->encoding->scale.q != 1)
+                                       *conv_d = (*conv_d * analog->encoding->scale.p) / analog->encoding->scale.q;
+                               double offset = ((double)analog->encoding->offset.p / (double)analog->encoding->offset.q);
+                               *conv_d += offset;
+
+                               outbuf[i] = *conv_d;
+                       }
+                       else {
+                               sr_err("Unsupported floating-point unit size '%d' for analog-to-float"
+                                      " conversion.", analog->encoding->unitsize);
+                               return SR_ERR;
+                       }
                }
        }
 
@@ -306,8 +331,10 @@ SR_API int sr_analog_to_float(const struct sr_datafeed_analog *analog,
  */
 SR_API const char *sr_analog_si_prefix(float *value, int *digits)
 {
-#define NEG_PREFIX_COUNT 5  /* number of prefixes below unity */
+/** @cond PRIVATE */
+#define NEG_PREFIX_COUNT 5 /* number of prefixes below unity */
 #define POS_PREFIX_COUNT (int)(ARRAY_SIZE(prefixes) - NEG_PREFIX_COUNT - 1)
+/** @endcond */
        static const char *prefixes[] = { "f", "p", "n", "µ", "m", "", "k", "M", "G", "T" };
 
        if (!value || !digits || isnan(*value))
@@ -363,12 +390,9 @@ SR_API gboolean sr_analog_si_prefix_friendly(enum sr_unit unit)
 
        for (i = 0; i < ARRAY_SIZE(prefix_friendly_units); i++)
                if (unit == prefix_friendly_units[i])
-                       break;
+                       return TRUE;
 
-       if (unit != prefix_friendly_units[i])
-               return FALSE;
-
-       return TRUE;
+       return FALSE;
 }
 
 /**
@@ -552,8 +576,8 @@ SR_API int sr_rational_mult(struct sr_rational *res, const struct sr_rational *a
                return SR_ERR_ARG;
        }
 
-       res->p = (int64_t)(p);
-       res->q = (uint64_t)(q);
+       res->p = (int64_t)p;
+       res->q = (uint64_t)q;
 
        return SR_OK;
 
@@ -603,9 +627,8 @@ SR_API int sr_rational_mult(struct sr_rational *res, const struct sr_rational *a
  * @param[out] res Result.
  *
  * @retval SR_OK Success.
- * @retval SR_ERR_ARG Division by zero.
- * @retval SR_ERR_ARG Denominator of divisor too large.
- * @retval SR_ERR_ARG Resulting value too large.
+ * @retval SR_ERR_ARG Division by zero, denominator of divisor too large,
+ *                    or resulting value too large.
  *
  * @since 0.5.0
  */