Permalink
Find file Copy path
7979690 Oct 5, 2018
1 contributor

Users who have contributed to this file

217 lines (153 sloc) 6.96 KB
/*
* QR Code generator library (C++)
*
* Copyright (c) Project Nayuki. (MIT License)
* https://www.nayuki.io/page/qr-code-generator-library
*
* 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>
#include "BitBuffer.hpp"
namespace qrcodegen {
/*
* A segment of character/binary/control data in a QR Code symbol.
* Instances of this class are immutable.
* The mid-level way to create a segment is to take the payload data
* and call a static factory function such as QrSegment::makeNumeric().
* The low-level way to create a segment is to custom-make the bit buffer
* and call the QrSegment() constructor with appropriate values.
* 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 ----*/
/*
* Describes how a segment's data bits are interpreted. Immutable.
*/
public: class Mode final {
/*-- Constants --*/
public: static const Mode NUMERIC;
public: static const Mode ALPHANUMERIC;
public: static const Mode BYTE;
public: static const Mode KANJI;
public: static const Mode ECI;
/*-- Fields --*/
// The mode indicator bits, which is a uint4 value (range 0 to 15).
private: int modeBits;
// Number of character count bits for three different version ranges.
private: int numBitsCharCount[3];
/*-- Constructor --*/
private: Mode(int mode, int cc0, int cc1, int cc2);
/*-- Methods --*/
/*
* (Package-private) Returns the mode indicator bits, which is an unsigned 4-bit value (range 0 to 15).
*/
public: int getModeBits() const;
/*
* (Package-private) Returns the bit width of the character count field for a segment in
* this mode in a QR Code at the given version number. The result is in the range [0, 16].
*/
public: int numCharCountBits(int ver) const;
};
/*---- Static factory functions (mid level) ----*/
/*
* Returns a segment representing the given binary data encoded in
* byte mode. All input byte vectors are acceptable. Any text string
* can be converted to UTF-8 bytes and encoded as a byte mode segment.
*/
public: static QrSegment makeBytes(const std::vector<std::uint8_t> &data);
/*
* Returns a segment representing the given string of decimal digits encoded in numeric mode.
*/
public: 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.
*/
public: 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.
*/
public: static std::vector<QrSegment> makeSegments(const char *text);
/*
* Returns a segment representing an Extended Channel Interpretation
* (ECI) designator with the given assignment value.
*/
public: static QrSegment makeEci(long assignVal);
/*---- Public static helper functions ----*/
/*
* Tests whether the given string can be encoded as a segment in alphanumeric mode.
* A string is encodable iff each character is in the following set: 0 to 9, A to Z
* (uppercase only), space, dollar, percent, asterisk, plus, hyphen, period, slash, colon.
*/
public: static bool isAlphanumeric(const char *text);
/*
* Tests whether the given string can be encoded as a segment in numeric mode.
* A string is encodable iff each character is in the range 0 to 9.
*/
public: static bool isNumeric(const char *text);
/*---- Instance fields ----*/
/* The mode indicator of this segment. Accessed through getMode(). */
private: Mode mode;
/* The length of this segment's unencoded data. Measured in characters for
* numeric/alphanumeric/kanji mode, bytes for byte mode, and 0 for ECI mode.
* Always zero or positive. Not the same as the data's bit length.
* Accessed through getNumChars(). */
private: int numChars;
/* The data bits of this segment. Accessed through getData(). */
private: std::vector<bool> data;
/*---- Constructors (low level) ----*/
/*
* Creates a new QR Code segment with the given attributes and data.
* The character count (numCh) must agree with the mode and the bit buffer length,
* but the constraint isn't checked. The given bit buffer is copied and stored.
*/
public: QrSegment(Mode md, int numCh, const std::vector<bool> &dt);
/*
* Creates a new QR Code segment with the given parameters and data.
* The character count (numCh) must agree with the mode and the bit buffer length,
* but the constraint isn't checked. The given bit buffer is moved and stored.
*/
public: QrSegment(Mode md, int numCh, std::vector<bool> &&dt);
/*---- Methods ----*/
/*
* Returns the mode field of this segment.
*/
public: Mode getMode() const;
/*
* Returns the character count field of this segment.
*/
public: int getNumChars() const;
/*
* Returns the data bits of this segment.
*/
public: const std::vector<bool> &getData() const;
// (Package-private) Calculates the number of bits needed to encode the given segments at
// the given version. Returns a non-negative number if successful. Otherwise returns -1 if a
// segment has too many characters to fit its length field, or the total bits exceeds INT_MAX.
public: static int getTotalBits(const std::vector<QrSegment> &segs, int version);
/*---- Private constant ----*/
/* The set of all legal characters in alphanumeric mode, where
* each character value maps to the index in the string. */
private: static const char *ALPHANUMERIC_CHARSET;
};
}