analog: add conversion from various integer formats to float

diff --git a/src/analog.c b/src/analog.c
index f26f7a5c2b931e0afa855cd0b106fa401ca7c3cf..892cc6ec15fe144229742bf1fc31ec786e7cbe59 100644 (file)
--- a/src/analog.c
+++ b/src/analog.c
@@ -187,9 +187,80 @@ SR_API int sr_analog_to_float(const struct sr_datafeed_analog *analog,
        bigendian = FALSE;
 #endif
        if (!analog->encoding->is_float) {
-               /* TODO */
-               sr_err("Only floating-point encoding supported so far.");
-               return SR_ERR;
+               float offset = analog->encoding->offset.p / (float)analog->encoding->offset.q;
+               float scale = analog->encoding->scale.p / (float)analog->encoding->scale.q;
+               gboolean is_signed = analog->encoding->is_signed;
+               gboolean is_bigendian = analog->encoding->is_bigendian;
+               int8_t *data8 = (int8_t *)(analog->data);
+               int16_t *data16 = (int16_t *)(analog->data);
+               int32_t *data32 = (int32_t *)(analog->data);
+
+               switch (analog->encoding->unitsize) {
+               case 1:
+                       if (is_signed) {
+                               for (unsigned int i = 0; i < count; i++) {
+                                       outbuf[i] = scale * data8[i];
+                                       outbuf[i] += offset;
+                               }
+                       } else {
+                               for (unsigned int i = 0; i < count; i++) {
+                                       outbuf[i] = scale * R8(data8 + i);
+                                       outbuf[i] += offset;
+                               }
+                       }
+                       break;
+               case 2:
+                       if (is_signed && is_bigendian) {
+                               for (unsigned int i = 0; i < count; i++) {
+                                       outbuf[i] = scale * RB16S(&data16[i]);
+                                       outbuf[i] += offset;
+                               }
+                       } else if (is_bigendian) {
+                               for (unsigned int i = 0; i < count; i++) {
+                                       outbuf[i] = scale * RB16(&data16[i]);
+                                       outbuf[i] += offset;
+                               }
+                       } else if (is_signed) {
+                               for (unsigned int i = 0; i < count; i++) {
+                                       outbuf[i] = scale * RL16S(&data16[i]);
+                                       outbuf[i] += offset;
+                               }
+                       } else {
+                               for (unsigned int i = 0; i < count; i++) {
+                                       outbuf[i] = scale * RL16(&data16[i]);
+                                       outbuf[i] += offset;
+                               }
+                       }
+                       break;
+               case 4:
+                       if (is_signed && is_bigendian) {
+                               for (unsigned int i = 0; i < count; i++) {
+                                       outbuf[i] = scale * RB32S(&data32[i]);
+                                       outbuf[i] += offset;
+                               }
+                       } else if (is_bigendian) {
+                               for (unsigned int i = 0; i < count; i++) {
+                                       outbuf[i] = scale * RB32(&data32[i]);
+                                       outbuf[i] += offset;
+                               }
+                       } else if (is_signed) {
+                               for (unsigned int i = 0; i < count; i++) {
+                                       outbuf[i] = scale * RL32S(&data32[i]);
+                                       outbuf[i] += offset;
+                               }
+                       } else {
+                               for (unsigned int i = 0; i < count; i++) {
+                                       outbuf[i] = scale * RL32(&data32[i]);
+                                       outbuf[i] += offset;
+                               }
+                       }
+                       break;
+               default:
+                       sr_err("Unsupported unit size '%d' for analog-to-float conversion.",
+                               analog->encoding->unitsize);
+                       return SR_ERR;
+               }
+               return SR_OK;
        }
 
        if (analog->encoding->unitsize == sizeof(float)

diff --git a/src/libsigrok-internal.h b/src/libsigrok-internal.h
index 41754b288ac9a7126953f323c18922c9209d981f..3413f9208fae0377e3633ef2c329bc9239394cdf 100644 (file)
--- a/src/libsigrok-internal.h
+++ b/src/libsigrok-internal.h
@@ -76,6 +76,15 @@ struct zip_stat;
 #define RL16(x)  (((unsigned)((const uint8_t*)(x))[1] <<  8) | \
                    (unsigned)((const uint8_t*)(x))[0])
 
+/**
+ * Read a 16 bits big endian signed integer out of memory.
+ * @param x a pointer to the input memory
+ * @return the corresponding signed integer
+ */
+#define RB16S(x)  ((int16_t) \
+                  (((unsigned)((const uint8_t*)(x))[0] <<  8) | \
+                    (unsigned)((const uint8_t*)(x))[1]))
+
 /**
  * Read a 16 bits little endian signed integer out of memory.
  * @param x a pointer to the input memory
@@ -105,6 +114,17 @@ struct zip_stat;
                   ((unsigned)((const uint8_t*)(x))[1] <<  8) |  \
                    (unsigned)((const uint8_t*)(x))[0])
 
+/**
+ * Read a 32 bits big endian signed integer out of memory.
+ * @param x a pointer to the input memory
+ * @return the corresponding signed integer
+ */
+#define RB32S(x)  ((int32_t) \
+                 (((unsigned)((const uint8_t*)(x))[0] << 24) | \
+                  ((unsigned)((const uint8_t*)(x))[1] << 16) | \
+                  ((unsigned)((const uint8_t*)(x))[2] <<  8) | \
+                   (unsigned)((const uint8_t*)(x))[3]))
+
 /**
  * Read a 32 bits little endian signed integer out of memory.
  * @param x a pointer to the input memory