fixed doc error, improved comments

bk: 4cdae497djbP-KTOl8dbSl3y7uWWcA

diff --git a/html/drivers/driver20.html b/html/drivers/driver20.html
index b30f06e0572b94825a5f73dbf3f432497a5300c2..3626fa30f3f4ea46a1daa6a04883793ef84a8fc2 100644 (file)
--- a/html/drivers/driver20.html
+++ b/html/drivers/driver20.html
@@ -210,7 +210,7 @@
        <td align="center">4</td>
        <td>process <tt>$GPGLL</tt></td>
       </tr><tr>
-       <td align="center">4</td>
+       <td align="center">3</td>
        <td align="center">8</td>
        <td>process <tt>$GPZDA</tt> or <tt>$GPZDG</tt></td>
       </tr><tr>

diff --git a/ntpd/refclock_nmea.c b/ntpd/refclock_nmea.c
index 094c3fb001a72134d110a7bedc7fa86599b89dd7..0b1a3da955f967b1d0a90b825cd5d6c39500fcbb 100644 (file)
--- a/ntpd/refclock_nmea.c
+++ b/ntpd/refclock_nmea.c
@@ -1132,9 +1132,11 @@ field_init(
 
        /* syntax check follows here. check allowed character
         * sequences, updating the local computed checksum as we go.
+        *
+        * regex equiv: '^\$[A-Z][A-Z0-9]{4,}[^*]*(\*[0-9A-F]{2})?$'
         */
 
-       /* -*- start character: [$] */
+       /* -*- start character: '^\$' */
        if (*cptr == '\0')
                return CHECK_EMPTY;
        if (*cptr++ != '$')
@@ -1145,7 +1147,7 @@ field_init(
        data->cptr++;
        data->blen--;
        
-       /* -*- field name: [A-Z][A-Z0-9]{4+}[,] */
+       /* -*- field name: '[A-Z][A-Z0-9]{4,},' */
        if (*cptr < 'A' || *cptr > 'Z')
                return CHECK_INVALID;
        cs_l ^= *cptr++;
@@ -1156,16 +1158,17 @@ field_init(
                return CHECK_INVALID;
        cs_l ^= *cptr++;
 
-       /* -*- data: [^*]* */
+       /* -*- data: '[^*]*' */
        while (*cptr && *cptr != '*')
                cs_l ^= *cptr++;
+       
+       /* -*- checksum field: (\*[0-9A-F]{2})?$ */
        if (*cptr == '\0')
                return CHECK_VALID;
        if (*cptr != '*' || cptr != eptr - 3 ||
            (cptr - data->base) >= NMEA_PROTO_MAXLEN)
                return CHECK_INVALID;
 
-       /* -*- checksum field: [*][0-9A-F]{2}$ */
        for (cptr++; (tmp = *cptr) != '\0'; cptr++)
                if (tmp >= '0' && tmp <= '9')
                        cs_r = (cs_r << 4) + (tmp - '0');