rename pfield preamble constant, add for CUC

src/time/cds.rs

@@ -6,7 +6,8 @@ use super::*;
 use crate::private::Sealed;
 use core::fmt::Debug;
 
-pub const CDS_SHORT_P_FIELD: u8 = (CcsdsTimeCodes::Cds as u8) << 4;
+/// Base value for the preamble field for a time field parser to determine the time field type.
+pub const P_FIELD_BASE: u8 = (CcsdsTimeCodes::Cds as u8) << 4;
 pub const MIN_CDS_FIELD_LEN: usize = 7;
 
 /// Generic trait implemented by token structs to specify the length of day field at type
@@ -391,7 +392,7 @@ impl<ProvidesDaysLen: ProvidesDaysLength> TimeProvider<ProvidesDaysLen> {
         day_seg_len: LengthOfDaySegment,
         submillis_prec: Option<SubmillisPrecision>,
     ) -> u8 {
-        let mut pfield = CDS_SHORT_P_FIELD | ((day_seg_len as u8) << 2);
+        let mut pfield = P_FIELD_BASE | ((day_seg_len as u8) << 2);
         if let Some(submillis_prec) = submillis_prec {
             match submillis_prec {
                 SubmillisPrecision::Microseconds(_) => pfield |= 0b01,

src/time/cuc.rs

@@ -6,6 +6,9 @@ use super::*;
 use core::fmt::Debug;
 
 const MIN_CUC_LEN: usize = 2;
+
+/// Base value for the preamble field for a time field parser to determine the time field type.
+pub const P_FIELD_BASE: u8 = (CcsdsTimeCodes::CucCcsdsEpoch as u8) << 4;
 /// Maximum length if the preamble field is not extended.
 pub const MAX_CUC_LEN_SMALL_PREAMBLE: usize = 8;
 
@@ -310,7 +313,7 @@ impl TimeProviderCcsdsEpoch {
     }
 
     fn build_p_field(counter_width: u8, fractions_width: Option<FractionalResolution>) -> u8 {
-        let mut pfield = (CcsdsTimeCodes::CucCcsdsEpoch as u8) << 4;
+        let mut pfield = P_FIELD_BASE;
         if !(1..=4).contains(&counter_width) {
             // Okay to panic here, this function is private and all input values should
             // have been sanitized