cobalt / cobalt / a7b1cfadc52288d71702934fd93743a24aea060a / . / src / third_party / QR-Code-generator / cpp / QrCode.hpp

/* | |

* 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 <string> | |

#include <vector> | |

#include "QrSegment.hpp" | |

namespace qrcodegen { | |

/* | |

* Represents an immutable square grid of black and white cells for a QR Code symbol, and | |

* provides static functions to create a QR Code from user-supplied textual or binary data. | |

* This class covers the QR Code model 2 specification, supporting all versions (sizes) | |

* from 1 to 40, all 4 error correction levels, and only 3 character encoding modes. | |

*/ | |

class QrCode final { | |

/*---- Public helper enumeration ----*/ | |

/* | |

* Represents the error correction level used in a QR Code symbol. | |

*/ | |

public: enum class Ecc { | |

// Constants declared in ascending order of error protection. | |

LOW = 0, MEDIUM = 1, QUARTILE = 2, HIGH = 3 | |

}; | |

// Returns a value in the range 0 to 3 (unsigned 2-bit integer). | |

private: static int getFormatBits(Ecc ecl); | |

/*---- Public static factory functions ----*/ | |

/* | |

* Returns a QR Code symbol representing the specified Unicode text string at the specified error correction level. | |

* As a conservative upper bound, this function is guaranteed to succeed for strings that have 2953 or fewer | |

* UTF-8 code units (not Unicode code points) if the low error correction level is used. The smallest possible | |

* QR Code version is automatically chosen for the output. The ECC level of the result may be higher than | |

* the ecl argument if it can be done without increasing the version. | |

*/ | |

public: static QrCode encodeText(const char *text, Ecc ecl, int minVersion); | |

/* | |

* Returns a QR Code symbol representing the given binary data string at the given error correction level. | |

* This function always encodes using the binary segment mode, not any text mode. The maximum number of | |

* bytes allowed is 2953. The smallest possible QR Code version is automatically chosen for the output. | |

* The ECC level of the result may be higher than the ecl argument if it can be done without increasing the version. | |

*/ | |

public: static QrCode encodeBinary(const std::vector<std::uint8_t> &data, Ecc ecl); | |

/* | |

* Returns a QR Code symbol representing the given data segments with the given encoding parameters. | |

* The smallest possible QR Code version within the given range is automatically chosen for the output. | |

* This function allows the user to create a custom sequence of segments that switches | |

* between modes (such as alphanumeric and binary) to encode text more efficiently. | |

* This function is considered to be lower level than simply encoding text or binary data. | |

*/ | |

public: static QrCode encodeSegments(const std::vector<QrSegment> &segs, Ecc ecl, | |

int minVersion=1, int maxVersion=40, int mask=-1, bool boostEcl=true); // All optional parameters | |

/*---- Public constants ----*/ | |

public: static constexpr int MIN_VERSION = 1; | |

public: static constexpr int MAX_VERSION = 40; | |

/*---- Instance fields ----*/ | |

// Immutable scalar parameters | |

/* This QR Code symbol's version number, which is always between 1 and 40 (inclusive). */ | |

private: int version; | |

/* The width and height of this QR Code symbol, measured in modules. | |

* Always equal to version × 4 + 17, in the range 21 to 177. */ | |

private: int size; | |

/* The error correction level used in this QR Code symbol. */ | |

private: Ecc errorCorrectionLevel; | |

/* The mask pattern used in this QR Code symbol, in the range 0 to 7 (i.e. unsigned 3-bit integer). | |

* Note that even if a constructor was called with automatic masking requested | |

* (mask = -1), the resulting object will still have a mask value between 0 and 7. */ | |

private: int mask; | |

// Private grids of modules/pixels (conceptually immutable) | |

private: std::vector<std::vector<bool> > modules; // The modules of this QR Code symbol (false = white, true = black) | |

private: std::vector<std::vector<bool> > isFunction; // Indicates function modules that are not subjected to masking | |

/*---- Constructors ----*/ | |

/* | |

* Creates a new QR Code symbol with the given version number, error correction level, binary data array, | |

* and mask number. This is a cumbersome low-level constructor that should not be invoked directly by the user. | |

* To go one level up, see the encodeSegments() function. | |

*/ | |

public: QrCode(int ver, Ecc ecl, const std::vector<std::uint8_t> &dataCodewords, int mask); | |

/*---- Public instance methods ----*/ | |

public: int getVersion() const; | |

public: int getSize() const; | |

public: Ecc getErrorCorrectionLevel() const; | |

public: int getMask() const; | |

/* | |

* Returns the color of the module (pixel) at the given coordinates, which is either | |

* false for white or true for black. The top left corner has the coordinates (x=0, y=0). | |

* If the given coordinates are out of bounds, then false (white) is returned. | |

*/ | |

public: bool getModule(int x, int y) const; | |

/* | |

* Based on the given number of border modules to add as padding, this returns a | |

* string whose contents represents an SVG XML file that depicts this QR Code symbol. | |

* Note that Unix newlines (\n) are always used, regardless of the platform. | |

*/ | |

public: std::string toSvgString(int border) const; | |

/*---- Private helper methods for constructor: Drawing function modules ----*/ | |

private: void drawFunctionPatterns(); | |

// Draws two copies of the format bits (with its own error correction code) | |

// based on the given mask and this object's error correction level field. | |

private: void drawFormatBits(int mask); | |

// Draws two copies of the version bits (with its own error correction code), | |

// based on this object's version field (which only has an effect for 7 <= version <= 40). | |

private: void drawVersion(); | |

// Draws a 9*9 finder pattern including the border separator, with the center module at (x, y). | |

private: void drawFinderPattern(int x, int y); | |

// Draws a 5*5 alignment pattern, with the center module at (x, y). | |

private: void drawAlignmentPattern(int x, int y); | |

// Sets the color of a module and marks it as a function module. | |

// Only used by the constructor. Coordinates must be in range. | |

private: void setFunctionModule(int x, int y, bool isBlack); | |

// Returns the color of the module at the given coordinates, which must be in range. | |

private: bool module(int x, int y) const; | |

/*---- Private helper methods for constructor: Codewords and masking ----*/ | |

// Returns a new byte string representing the given data with the appropriate error correction | |

// codewords appended to it, based on this object's version and error correction level. | |

private: std::vector<std::uint8_t> appendErrorCorrection(const std::vector<std::uint8_t> &data) const; | |

// Draws the given sequence of 8-bit codewords (data and error correction) onto the entire | |

// data area of this QR Code symbol. Function modules need to be marked off before this is called. | |

private: void drawCodewords(const std::vector<std::uint8_t> &data); | |

// XORs the data modules in this QR Code with the given mask pattern. Due to XOR's mathematical | |

// properties, calling applyMask(m) twice with the same value is equivalent to no change at all. | |

// This means it is possible to apply a mask, undo it, and try another mask. Note that a final | |

// well-formed QR Code symbol needs exactly one mask applied (not zero, not two, etc.). | |

private: void applyMask(int mask); | |

// A messy helper function for the constructors. This QR Code must be in an unmasked state when this | |

// method is called. The given argument is the requested mask, which is -1 for auto or 0 to 7 for fixed. | |

// This method applies and returns the actual mask chosen, from 0 to 7. | |

private: int handleConstructorMasking(int mask); | |

// Calculates and returns the penalty score based on state of this QR Code's current modules. | |

// This is used by the automatic mask choice algorithm to find the mask pattern that yields the lowest score. | |

private: long getPenaltyScore() const; | |

/*---- Private static helper functions ----*/ | |

// Returns a set of positions of the alignment patterns in ascending order. These positions are | |

// used on both the x and y axes. Each value in the resulting array is in the range [0, 177). | |

// This stateless pure function could be implemented as table of 40 variable-length lists of unsigned bytes. | |

private: static std::vector<int> getAlignmentPatternPositions(int ver); | |

// Returns the number of data bits that can be stored in a QR Code of the given version number, after | |

// all function modules are excluded. This includes remainder bits, so it might not be a multiple of 8. | |

// The result is in the range [208, 29648]. This could be implemented as a 40-entry lookup table. | |

private: static int getNumRawDataModules(int ver); | |

// Returns the number of 8-bit data (i.e. not error correction) codewords contained in any | |

// QR Code of the given version number and error correction level, with remainder bits discarded. | |

// This stateless pure function could be implemented as a (40*4)-cell lookup table. | |

private: static int getNumDataCodewords(int ver, Ecc ecl); | |

/*---- Private tables of constants ----*/ | |

// For use in getPenaltyScore(), when evaluating which mask is best. | |

private: static const int PENALTY_N1; | |

private: static const int PENALTY_N2; | |

private: static const int PENALTY_N3; | |

private: static const int PENALTY_N4; | |

private: static const std::int8_t ECC_CODEWORDS_PER_BLOCK[4][41]; | |

private: static const std::int8_t NUM_ERROR_CORRECTION_BLOCKS[4][41]; | |

/*---- Private helper class ----*/ | |

/* | |

* Computes the Reed-Solomon error correction codewords for a sequence of data codewords | |

* at a given degree. Objects are immutable, and the state only depends on the degree. | |

* This class exists because each data block in a QR Code shares the same the divisor polynomial. | |

*/ | |

private: class ReedSolomonGenerator final { | |

/*-- Immutable field --*/ | |

// Coefficients of the divisor polynomial, stored from highest to lowest power, excluding the leading term which | |

// is always 1. For example the polynomial x^3 + 255x^2 + 8x + 93 is stored as the uint8 array {255, 8, 93}. | |

private: std::vector<std::uint8_t> coefficients; | |

/*-- Constructor --*/ | |

/* | |

* Creates a Reed-Solomon ECC generator for the given degree. This could be implemented | |

* as a lookup table over all possible parameter values, instead of as an algorithm. | |

*/ | |

public: explicit ReedSolomonGenerator(int degree); | |

/*-- Method --*/ | |

/* | |

* Computes and returns the Reed-Solomon error correction codewords for the given | |

* sequence of data codewords. The returned object is always a new byte array. | |

* This method does not alter this object's state (because it is immutable). | |

*/ | |

public: std::vector<std::uint8_t> getRemainder(const std::vector<std::uint8_t> &data) const; | |

/*-- Static function --*/ | |

// Returns the product of the two given field elements modulo GF(2^8/0x11D). | |

// All inputs are valid. This could be implemented as a 256*256 lookup table. | |

private: static std::uint8_t multiply(std::uint8_t x, std::uint8_t y); | |

}; | |

}; | |

} |