Add a number of printHex helper functions

These allow easily printing integers and XBeeAddress64 values with
leading zeroes (which Arduino's print doesn't have any easy way to do).
Also, a version is available that can print a buffer of bytes with
configurable separators.

These functions aren't used yet, but will be used in examples that will
be added next.

Author: matthijskooijman

Printers.cpp

@@ -0,0 +1,23 @@
+#include "Printers.h"
+
+void printHex(Print& p, const uint8_t* buf, size_t len, const __FlashStringHelper* byte_sep, const __FlashStringHelper* group_sep, size_t group_by) {
+	size_t cur_group = 0;
+	while (len--) {
+		// Print the group separator whenever starting a new
+		// group
+		if (group_by && group_sep && cur_group == group_by) {
+			p.print(group_sep);
+			cur_group = 0;
+		}
+
+		// Print the byte separator, except when at the start of
+		// a new group (this also excludes the first byte)
+		if (cur_group != 0 && byte_sep)
+			p.print(byte_sep);
+
+		printHex(p, *buf);
+
+		buf++;
+		cur_group++;
+	}
+}

Printers.h

@@ -0,0 +1,88 @@
+/**
+ * Copyright (c) 2009 Andrew Rapp. All rights reserved.
+ *
+ * This file is part of XBee-Arduino.
+ *
+ * XBee-Arduino is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * XBee-Arduino is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with XBee-Arduino.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef XBee_Printers_h
+#define XBee_Printers_h
+
+#if defined(ARDUINO) && ARDUINO >= 100
+	#include "Arduino.h"
+#else
+	#include "WProgram.h"
+#endif
+
+#include "XBee.h"
+
+// Need to define global variables to allow PROGMEM pointers as default
+// arguments below. Since these variables are const, there won't be any
+// linker conflicts from defining these in a header file.
+const char default_byte_sep_arr[] PROGMEM = " ";
+const char default_group_sep_arr[] PROGMEM = "\r\n";
+const __FlashStringHelper * const default_byte_sep = (const __FlashStringHelper*)default_byte_sep_arr;
+const __FlashStringHelper * const default_group_sep = (const __FlashStringHelper*)default_group_sep_arr;
+
+/**
+ * Print a buffer byte-by-byte. Each byte is separated by byte_sep and
+ * every group_by bytes are separated by group_sep instead.
+ *
+ * For example, to print 8 bytes per line, each byte separated by a
+ * newline, to Serial:
+ *
+ * printHex(Serial, buf, len, F(" "), F("\r\n"), 8);
+ *
+ * Values shown are also the defaults.
+ *
+ * Pass NULL as group_by or byte_sep to not have that separator.
+ */
+void printHex(Print& p, const uint8_t* buf, size_t len, const __FlashStringHelper* byte_sep = default_byte_sep, const __FlashStringHelper* group_sep = default_group_sep, size_t group_by = 8);
+
+/**
+ * Print a single byte, in hex, using a leading zero if needed.
+ */
+inline void printHex(Print& p, uint8_t v) {
+	// Add leading zero if needed
+	if (v < 0x10)
+		p.write('0');
+	p.print(v, HEX);
+}
+
+/**
+ * Print a 16 bit integer, in hex, using leading zeroes if needed.
+ */
+inline void printHex(Print& p, uint16_t v) {
+	printHex(p, (uint8_t)(v >> 8));
+	printHex(p, (uint8_t)v);
+}
+
+/**
+ * Print a 32 bit integer, in hex, using leading zeroes if needed.
+ */
+inline void printHex(Print& p, uint32_t v) {
+	printHex(p, (uint16_t)(v >> 16));
+	printHex(p, (uint16_t)v);
+}
+
+/**
+ * Print a 64-bit address, in hex, using leading zeroes if needed.
+ */
+inline void printHex(Print& p, XBeeAddress64 v) {
+	printHex(p, v.getMsb());
+	printHex(p, v.getLsb());
+}
+
+#endif // XBee_Printers_h