2540. [func] Add a nibble mode to $GENERATE. [RT #1887]

CHANGES

@@ -1,3 +1,5 @@
+2540.	[func]		Add a nibble mode to $GENERATE. [RT #18872]
+
 2539.	[security]	Update the interaction between recursion, allow-query,
 			allow-query-cache and allow-recursion.  [RT #19198]
 

doc/arm/Bv9ARM-book.xml

@@ -18,7 +18,7 @@
  - PERFORMANCE OF THIS SOFTWARE.
 -->
 
-<!-- File: $Id: Bv9ARM-book.xml,v 1.390 2009/01/30 03:48:54 marka Exp $ -->
+<!-- File: $Id: Bv9ARM-book.xml,v 1.391 2009/01/30 04:35:44 marka Exp $ -->
 <book xmlns:xi="http://www.w3.org/2001/XInclude">
   <title>BIND 9 Administrator Reference Manual</title>
 
@@ -11476,20 +11476,30 @@ HOST-127.EXAMPLE. MX 0 .
 
 		      Available output forms are decimal
                       (<command>d</command>), octal
-                      (<command>o</command>) and hexadecimal
+                      (<command>o</command>), hexadecimal
                       (<command>x</command> or <command>X</command>
-                      for uppercase).  The default modifier is
+                      for uppercase) and nibble
+		      (<command>n</command> or <command>N</command>\
+		      for uppercase).  The default modifier is
                       <command>${0,0,d}</command>.  If the
                       <command>lhs</command> is not absolute, the
                       current <command>$ORIGIN</command> is appended
                       to the name.
                     </para>
-                    <para>
-                      For compatibility with earlier versions, <command>$$</command> is still
-                      recognized as indicating a literal $ in the output.
-                    </para>
-                  </entry>
-                </row>
+		    <para>
+		      In nibble mode the value will be treated as
+		      a if it was a reversed hexadecimal string
+		      with each hexadecimal digit as a seperate
+		      label.  The width field includes the label
+		      seperator.
+		    </para>
+		    <para>
+		      For compatibility with earlier versions,
+		      <command>$$</command> is still recognized as
+		      indicating a literal $ in the output.
+		    </para>
+		  </entry>
+		</row>
                 <row rowsep="0">
                   <entry colname="1">
                     <para><command>ttl</command></para>

lib/dns/master.c

@@ -15,7 +15,7 @@
  * PERFORMANCE OF THIS SOFTWARE.
  */
 
-/* $Id: master.c,v 1.174 2009/01/17 23:47:42 tbox Exp $ */
+/* $Id: master.c,v 1.175 2009/01/30 04:35:44 marka Exp $ */
 
 /*! \file */
 
@@ -618,6 +618,57 @@ loadctx_create(dns_masterformat_t format, isc_mem_t *mctx,
 	return (result);
 }
 
+static const char *hex = "0123456789abcdef0123456789ABCDEF";
+
+/*%
+ * Convert value into a nibble sequence from least significant to most
+ * significant nibble.  Zero fill upper most significant nibbles if
+ * required to make the width.
+ *
+ * Returns the number of characters that should have been written without
+ * counting the terminating NUL.
+ */
+static unsigned int
+nibbles(char *numbuf, size_t length, unsigned int width, char mode, int value) {
+	unsigned int count = 0;
+
+	/*
+	 * This reserve space for the NUL string terminator.
+	 */
+	if (length > 0) {
+		*numbuf = '\0';
+		length--;
+	}
+	do {
+		char val = hex[(value & 0x0f) + ((mode == 'n') ? 0 : 16)];
+		value >>= 4;
+		if (length > 0) {
+			*numbuf++ = val;
+			*numbuf = '\0';
+			length--;
+		}
+		if (width > 0)
+			width--;
+		count++;
+		/*
+		 * If width is non zero then we need to add a label seperator.
+		 * If value is non zero then we need to add another label and
+		 * that requires a label seperator.
+		 */
+		if (width > 0 || value != 0) {
+			if (length > 0) {
+				*numbuf++ = '.';
+				*numbuf = '\0';
+				length--;
+			}
+			if (width > 0)
+				width--;
+			count++;
+		}
+	} while (value != 0 || width > 0);
+	return (count);
+}
+
 static isc_result_t
 genname(char *name, int it, char *buffer, size_t length) {
 	char fmt[sizeof("%04000000000d")];
@@ -628,6 +679,7 @@ genname(char *name, int it, char *buffer, size_t length) {
 	isc_textregion_t r;
 	unsigned int n;
 	unsigned int width;
+	isc_boolean_t nibblemode;
 
 	r.base = buffer;
 	r.length = length;
@@ -642,10 +694,11 @@ genname(char *name, int it, char *buffer, size_t length) {
 				isc_textregion_consume(&r, 1);
 				continue;
 			}
+			nibblemode = ISC_FALSE;
 			strcpy(fmt, "%d");
 			/* Get format specifier. */
 			if (*name == '{' ) {
-				n = sscanf(name, "{%d,%u,%1[doxX]}",
+				n = sscanf(name, "{%d,%u,%1[doxXnN]}",
 					   &delta, &width, mode);
 				switch (n) {
 				case 1:
@@ -655,6 +708,8 @@ genname(char *name, int it, char *buffer, size_t length) {
 						     "%%0%ud", width);
 					break;
 				case 3:
+					if (mode[0] == 'n' || mode[0] == 'N')
+						nibblemode = ISC_TRUE;
 					n = snprintf(fmt, sizeof(fmt),
 						     "%%0%u%c", width, mode[0]);
 					break;
@@ -667,7 +722,12 @@ genname(char *name, int it, char *buffer, size_t length) {
 				while (*name != '\0' && *name++ != '}')
 					continue;
 			}
-			n = snprintf(numbuf, sizeof(numbuf), fmt, it + delta);
+			if (nibblemode)
+				n = nibbles(numbuf, sizeof(numbuf), width,
+					    mode[0], it + delta);
+			else
+				n = snprintf(numbuf, sizeof(numbuf), fmt,
+					     it + delta);
 			if (n >= sizeof(numbuf))
 				return (ISC_R_NOSPACE);
 			cp = numbuf;