Add a get_bitfield function for byte arrays.

2 files changed, 51 insertions, 9 deletions

diff --git a/src/canutil/read.c b/src/canutil/read.c
index 4864a60f..3931721a 100644
--- a/src/canutil/read.c
+++ b/src/canutil/read.c
@@ -4,7 +4,7 @@
 
 float eightbyte_parse_float(uint64_t data, uint8_t bit_offset, uint8_t bit_size,
         float factor, float offset) {
-    uint64_t raw = eightbyte_get_bit_field(data, bit_offset, bit_size, true);
+    uint64_t raw = eightbyte_get_bitfield(data, bit_offset, bit_size, true);
     return raw * factor + offset;
 }
 
@@ -14,9 +14,19 @@ bool eightbyte_parse_bool(uint64_t data, uint8_t bit_offset, uint8_t bit_size,
     return value == 0.0 ? false : true;
 }
 
-float bitfield_parse_float(const uint8_t data[], const uint16_t size,
+float bitfield_parse_float(const uint8_t source[], const uint16_t source_length,
         const uint8_t bit_offset, const uint8_t bit_size, const float factor,
         const float offset) {
-    //TODO
-    return 0;
+    uint64_t raw = get_bitfield(source, source_length, bit_offset, bit_size);
+    // TODO seems dumb that this is repeated from eightbyte_parse_float - is it
+    // really worth keeping around these two implementations?
+    return raw * factor + offset;
+}
+
+float bitfield_parse_bool(const uint8_t source[], const uint16_t source_length,
+        const uint8_t bit_offset, const uint8_t bit_size, const float factor,
+        const float offset) {
+    float value = bitfield_parse_float(source, source_length, bit_offset,
+            bit_size, factor, offset);
+    return value == 0.0 ? false : true;
 }
diff --git a/src/canutil/read.h b/src/canutil/read.h
index bf6c0ade..733e3509 100644
--- a/src/canutil/read.h
+++ b/src/canutil/read.h
@@ -10,7 +10,7 @@ extern "C" {
 
 /* Public: Parse a CAN signal from a message and apply required transformation.
  *
- * data - the payload containing the signal.
+ * source - the payload containing the signal.
  * bit_offset - the starting bit for the signal.
  * bit_size - the width of the signal.
  * factor - the transformation factor for the signal value, applied after
@@ -20,16 +20,30 @@ extern "C" {
  *
  * Returns the decoded and transformed value of the signal.
  */
-float eightbyte_parse_float(const uint64_t data, const uint8_t bit_offset,
+float eightbyte_parse_float(const uint64_t source, const uint8_t bit_offset,
         const uint8_t bit_size, const float factor, const float offset);
 
-float bitfield_parse_float(const uint8_t data[], const uint16_t size,
+/* Public: Parse a CAN signal from a message storage as a byte array and apply
+ * required transformation.
+ *
+ * source - the payload containing the signal.
+ * source_size - the size of the payload in bytes.
+ * bit_offset - the starting bit for the signal.
+ * bit_size - the width of the signal.
+ * factor - the transformation factor for the signal value, applied after
+ *      pulling out the bit field. Use 1.0 for no factor.
+ * offset - the transformation offset for the signal value, applied after
+ *      pulling out the bit field. Use 0 for no offset.
+ *
+ * Returns the decoded and transformed value of the signal.
+ */
+float bitfield_parse_float(const uint8_t source[], const uint16_t source_size,
         const uint8_t bit_offset, const uint8_t bit_size, const float factor,
         const float offset);
 
 /* Public: Parse a CAN signal from a message and interpret it as a boolean.
  *
- * data - the payload containing the signal.
+ * source - the payload containing the signal.
  * bit_offset - the starting bit for the signal.
  * bit_size - the width of the signal.
  * factor - the transformation factor for the signal value, applied after
@@ -39,9 +53,27 @@ float bitfield_parse_float(const uint8_t data[], const uint16_t size,
  *
  * Returns false if the value was 0, otherwise true.
  */
-bool eightbyte_parse_bool(uint64_t data, uint8_t bit_offset, uint8_t bit_size,
+bool eightbyte_parse_bool(uint64_t source, uint8_t bit_offset, uint8_t bit_size,
         float factor, float offset);
 
+/* Public: Parse a CAN signal from a message storage as a byte array and
+ * interpret it as a boolean.
+ *
+ * source - the payload containing the signal.
+ * source_size - the size of the payload in bytes.
+ * bit_offset - the starting bit for the signal.
+ * bit_size - the width of the signal.
+ * factor - the transformation factor for the signal value, applied after
+ *      pulling out the bit field. Use 1.0 for no factor.
+ * offset - the transformation offset for the signal value, applied after
+ *      pulling out the bit field. Use 0 for no offset.
+ *
+ * Returns false if the value was 0, otherwise true.
+ */
+float bitfield_parse_float(const uint8_t source[], const uint16_t source_size,
+        const uint8_t bit_offset, const uint8_t bit_size, const float factor,
+        const float offset);
+
 #ifdef __cplusplus
 }
 #endif