fix: cdma send length | also some refactoring & added comments

1 files changed, 13 insertions, 8 deletions

diff --git a/src/pdu.h b/src/pdu.h
index 0143f1f..35c43a6 100644
--- a/src/pdu.h
+++ b/src/pdu.h
@@ -49,12 +49,13 @@ enum {
 	PDU_VPF_ABSOUTE = 3,
 };
 
+//PDU data formats (how the data was represented before encoding)
 enum {
-	PDU_ALPHABET_DEFAULT = 0,  //7-bit
-	PDU_ALPHABET_CDMA_DEFAULT = 2, //7-bit
-	PDU_ALPHABET_EIGHT = 4,
-	PDU_ALPHABET_CDMA_EIGHT = 8,
-	PDU_ALPHABET_DEFAULT_MULTI = 9,
+	PDU_ALPHABET_DEFAULT = 0,      //GSM 7-bit,  (supposedly CDMA 8-bit but haven't seen it)
+	PDU_ALPHABET_CDMA_DEFAULT = 2, //no GSM,     CDMA 7-bit
+	PDU_ALPHABET_EIGHT = 4,        //GSM 8-bit,  CDMA 16-bit unicode
+	PDU_ALPHABET_CDMA_EIGHT = 8,   //GSM 16-bit, CDMA 8-bit (what CDMA radios are actually using)
+	PDU_ALPHABET_DEFAULT_MULTI = 9,//no GSM,     LVW2 7-bit, multi-part
 };
 
 struct pdu_info {
@@ -117,10 +118,14 @@ int pdu_user_data_read(int fd, struct pdu_info *pdu);
 #define cycleup(n, mod)		((n) % (mod))
 #define cycledown(n, mod)	((mod - 1) - ((n) % (mod)))
 
-#define octet_align(n)		((((n) * 7) + ((-(n) * 7) & 7)) / 8)
+//Returns the number of octets the given septets (normal ascii) can be encoded to
+#define octets_from_septets(n)		((((n) * 7) + ((-(n) * 7) & 7)) / 8)
 
-#define septet_idx(n)		     ((n) * 8 / 7)
-#define octet_align_cdma(n)  septet_idx(n)
+//Returns the number of septets the given octets will decode to
+#define septets_from_octets(n)		   ((n) * 8 / 7)
+
+#define octet_idx(n)		     octets_from_septets(n)
+#define septet_idx(n)		     septets_from_octets(n)
 
 
 #define STRLEN_CHECK(str, len, ret) \