Add/use BITFIELD macros for defining/using multi-bit bit-fields

src/smblib/smbdefs.h

@@ -368,18 +368,16 @@ typedef struct {		/* Time with time-zone */
 } when_t;
 
 // We encode Month/Day/Hour/Min/Sec into 26 bits:
-#define SMB_DATE_MK_MASK(width, shift)	(((1 << (width)) - 1) << shift)
-#define SMB_DATE_MON_SHIFT		22
-#define SMB_DATE_MON_MASK		SMB_DATE_MK_MASK(4, SMB_DATE_MON_SHIFT)
-#define SMB_DATE_DAY_SHIFT		17
-#define SMB_DATE_DAY_MASK		SMB_DATE_MK_MASK(5, SMB_DATE_DAY_SHIFT)
-#define SMB_DATE_HR_SHIFT		12
-#define SMB_DATE_HR_MASK		SMB_DATE_MK_MASK(5, SMB_DATE_HR_SHIFT)
-#define SMB_DATE_MIN_SHIFT		6
-#define SMB_DATE_MIN_MASK		SMB_DATE_MK_MASK(6, SMB_DATE_MIN_SHIFT)
-#define SMB_DATE_SEC_SHIFT		0
-#define SMB_DATE_SEC_MASK		SMB_DATE_MK_MASK(6, SMB_DATE_SEC_SHIFT)
-#define SMB_DATE_MASK			(SMB_DATE_MON_MASK | SMB_DATE_DAY_MASK | SMB_DATE_HR_MASK | SMB_DATE_MIN_MASK | SMB_DATE_SEC_MASK)
+#define SMB_DATE_MON_BITWIDTH	4
+#define SMB_DATE_MON_BITPOS		22
+#define SMB_DATE_DAY_BITWIDTH	5
+#define SMB_DATE_DAY_BITPOS		17
+#define SMB_DATE_HR_BITWIDTH	5
+#define SMB_DATE_HR_BITPOS		12
+#define SMB_DATE_MIN_BITWIDTH	6
+#define SMB_DATE_MIN_BITPOS		6
+#define SMB_DATE_SEC_BITWIDTH	6
+#define SMB_DATE_SEC_BITPOS		0
 
 typedef uint16_t smb_msg_attr_t;
 

src/smblib/smblib.c

@@ -2118,6 +2118,13 @@ int smb_tzutc(int16_t zone)
 	return(tz);
 }
 
+#define SMB_DATE_MASK (\
+	BITFIELD_MASK(SMB_DATE_MON_BITWIDTH, SMB_DATE_MON_BITPOS) | \
+	BITFIELD_MASK(SMB_DATE_DAY_BITWIDTH, SMB_DATE_DAY_BITPOS) | \
+	BITFIELD_MASK(SMB_DATE_HR_BITWIDTH, SMB_DATE_HR_BITPOS) | \
+	BITFIELD_MASK(SMB_DATE_MIN_BITWIDTH, SMB_DATE_MIN_BITPOS) | \
+	BITFIELD_MASK(SMB_DATE_SEC_BITWIDTH, SMB_DATE_SEC_BITPOS))
+
 /****************************************************************************/
 /* Decode the 2 possible encoding of when_t (when_written)					*/
 /****************************************************************************/
@@ -2129,11 +2136,11 @@ time_t smb_time(when_t when)
 		return when.time;
 
 	tm.tm_year = when.year;
-	tm.tm_mon = (when.time & SMB_DATE_MON_MASK) >> SMB_DATE_MON_SHIFT;
-	tm.tm_mday = (when.time & SMB_DATE_DAY_MASK) >> SMB_DATE_DAY_SHIFT;
-	tm.tm_hour = (when.time & SMB_DATE_HR_MASK) >> SMB_DATE_HR_SHIFT;
-	tm.tm_min = (when.time & SMB_DATE_MIN_MASK) >> SMB_DATE_MIN_SHIFT;
-	tm.tm_sec = (when.time & SMB_DATE_SEC_MASK) >> SMB_DATE_SEC_SHIFT;
+	tm.tm_mon = BITFIELD_DECODE(when.time, SMB_DATE_MON_BITWIDTH, SMB_DATE_MON_BITPOS);
+	tm.tm_mday = BITFIELD_DECODE(when.time, SMB_DATE_DAY_BITWIDTH, SMB_DATE_DAY_BITPOS);
+	tm.tm_hour = BITFIELD_DECODE(when.time, SMB_DATE_HR_BITWIDTH, SMB_DATE_HR_BITPOS);
+	tm.tm_min = BITFIELD_DECODE(when.time, SMB_DATE_MIN_BITWIDTH, SMB_DATE_MIN_BITPOS);
+	tm.tm_sec = BITFIELD_DECODE(when.time, SMB_DATE_SEC_BITWIDTH, SMB_DATE_SEC_BITPOS);
 
 	return sane_mktime(&tm);
 }
@@ -2148,11 +2155,11 @@ when_t smb_when(time_t t, int16_t zone)
 
 	localtime_r(&t, &tm);
 	when.year = 1900 + tm.tm_year;
-	when.time = (tm.tm_mon + 1) << SMB_DATE_MON_SHIFT;
-	when.time |= tm.tm_mday << SMB_DATE_DAY_SHIFT;
-	when.time |= tm.tm_hour << SMB_DATE_HR_SHIFT;
-	when.time |= tm.tm_min << SMB_DATE_MIN_SHIFT;
-	when.time |= tm.tm_sec << SMB_DATE_SEC_SHIFT;
+	when.time = BITFIELD_ENCODE(tm.tm_mon + 1, SMB_DATE_MON_BITWIDTH, SMB_DATE_MON_BITPOS);
+	when.time |= BITFIELD_ENCODE(tm.tm_mday, SMB_DATE_DAY_BITWIDTH, SMB_DATE_DAY_BITPOS);
+	when.time |= BITFIELD_ENCODE(tm.tm_hour, SMB_DATE_HR_BITWIDTH, SMB_DATE_HR_BITPOS);
+	when.time |= BITFIELD_ENCODE(tm.tm_min, SMB_DATE_MIN_BITWIDTH, SMB_DATE_MIN_BITPOS);
+	when.time |= BITFIELD_ENCODE(tm.tm_sec, SMB_DATE_SEC_BITWIDTH, SMB_DATE_SEC_BITPOS);
 	when.zone = zone;
 
 	return when;

src/xpdev/gen_defs.h

@@ -402,6 +402,12 @@ typedef struct {
 /* Handy Integer Macros */
 /************************/
 
+/* Multi-bit bit-fields with "defined behavior" */
+#define BITFIELD_MAX(width)					((1 << (width)) - 1)
+#define BITFIELD_MASK(width, pos)			(BITFIELD_MAX(width) << (pos))
+#define BITFIELD_ENCODE(val, width, pos)	(((val) & BITFIELD_MAX(width)) << (pos))
+#define BITFIELD_DECODE(val, width, pos)	(((val) & BITFIELD_MASK(width, pos)) >> (pos))
+
 /* Data Block Length Alignment Macro (returns required padding length for proper alignment) */
 #define PAD_LENGTH_FOR_ALIGNMENT(len,blk)       (((len)%(blk))==0 ? 0 : (blk)-((len)%(blk)))