Add QR code display on the receive page

This embeds MIT licenced code from Project Nayuki:
https://www.nayuki.io/page/qr-code-generator-library
The C++ part of the code is embedded in src/QR-Code-generator.
See src/QR-Code-generator/Readme.markdown for more info.

1 files changed, 170 insertions, 0 deletions

diff --git a/src/QR-Code-generator/QrSegment.hpp b/src/QR-Code-generator/QrSegment.hpp
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+/* 
+ * QR Code generator library (C++)
+ * 
+ * Copyright (c) 2016 Project Nayuki
+ * https://www.nayuki.io/page/qr-code-generator-library
+ * 
+ * (MIT License)
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to
+ * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+ * the Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ * - The above copyright notice and this permission notice shall be included in
+ *   all copies or substantial portions of the Software.
+ * - The Software is provided "as is", without warranty of any kind, express or
+ *   implied, including but not limited to the warranties of merchantability,
+ *   fitness for a particular purpose and noninfringement. In no event shall the
+ *   authors or copyright holders be liable for any claim, damages or other
+ *   liability, whether in an action of contract, tort or otherwise, arising from,
+ *   out of or in connection with the Software or the use or other dealings in the
+ *   Software.
+ */
+
+#pragma once
+
+#include <cstdint>
+#include <vector>
+
+
+namespace qrcodegen {
+
+/* 
+ * Represents a character string to be encoded in a QR Code symbol. Each segment has
+ * a mode, and a sequence of characters that is already encoded as a sequence of bits.
+ * Instances of this class are immutable.
+ * This segment class imposes no length restrictions, but QR Codes have restrictions.
+ * Even in the most favorable conditions, a QR Code can only hold 7089 characters of data.
+ * Any segment longer than this is meaningless for the purpose of generating QR Codes.
+ */
+class QrSegment final {
+	
+	/*---- Public helper enumeration ----*/
+	
+	/* 
+	 * The mode field of a segment. Immutable. Provides methods to retrieve closely related values.
+	 */
+public:
+	class Mode final {
+		
+		/*-- Constants --*/
+	public:
+		
+		static const Mode NUMERIC;
+		static const Mode ALPHANUMERIC;
+		static const Mode BYTE;
+		static const Mode KANJI;
+		
+		
+		/*-- Fields --*/
+		
+		/* (Package-private) An unsigned 4-bit integer value (range 0 to 15) representing the mode indicator bits for this mode object. */
+	public:
+		const int modeBits;
+		
+	private:
+		int numBitsCharCount[3];
+		
+		
+		/*-- Constructor --*/
+		
+	private:
+		Mode(int mode, int cc0, int cc1, int cc2);
+		
+		
+		/*-- Method --*/
+		
+		/* 
+		 * (Package-private) Returns the bit width of the segment character count field for this mode object at the given version number.
+		 */
+	public:
+		int numCharCountBits(int ver) const;
+		
+	};
+	
+	
+	
+	/*---- Public static factory functions ----*/
+public:
+	
+	/* 
+	 * Returns a segment representing the given binary data encoded in byte mode.
+	 */
+	static QrSegment makeBytes(const std::vector<uint8_t> &data);
+	
+	
+	/* 
+	 * Returns a segment representing the given string of decimal digits encoded in numeric mode.
+	 */
+	static QrSegment makeNumeric(const char *digits);
+	
+	
+	/* 
+	 * Returns a segment representing the given text string encoded in alphanumeric mode. The characters allowed are:
+	 * 0 to 9, A to Z (uppercase only), space, dollar, percent, asterisk, plus, hyphen, period, slash, colon.
+	 */
+	static QrSegment makeAlphanumeric(const char *text);
+	
+	
+	/* 
+	 * Returns a list of zero or more segments to represent the given text string.
+	 * The result may use various segment modes and switch modes to optimize the length of the bit stream.
+	 */
+	static std::vector<QrSegment> makeSegments(const char *text);
+	
+	
+	/*---- Public static helper functions ----*/
+public:
+	
+	/* 
+	 * Tests whether the given string can be encoded as a segment in alphanumeric mode.
+	 */
+	static bool isAlphanumeric(const char *text);
+	
+	
+	/* 
+	 * Tests whether the given string can be encoded as a segment in numeric mode.
+	 */
+	static bool isNumeric(const char *text);
+	
+	
+	
+	/*---- Instance fields ----*/
+public:
+	
+	/* The mode indicator for this segment. */
+	const Mode mode;
+	
+	/* The length of this segment's unencoded data, measured in characters. Always zero or positive. */
+	const int numChars;
+	
+	/* The bits of this segment packed into a byte array in big endian. */
+	const std::vector<uint8_t> data;
+	
+	/* The length of this segment's encoded data, measured in bits. Satisfies ceil(bitLength / 8) = data.size(). */
+	const int bitLength;
+	
+	
+	/*---- Constructor ----*/
+public:
+	
+	/* 
+	 * Creates a new QR Code data segment with the given parameters and data.
+	 */
+	QrSegment(const Mode &md, int numCh, const std::vector<uint8_t> &b, int bitLen);
+	
+	
+	// Package-private helper function.
+	static int getTotalBits(const std::vector<QrSegment> &segs, int version);
+	
+	
+	/*---- Private constant ----*/
+private:
+	
+	/* Maps shifted ASCII codes to alphanumeric mode character codes. */
+	static const int8_t ALPHANUMERIC_ENCODING_TABLE[59];
+	
+};
+
+}