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/* | |
* 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 <array> | |
#include <cstdint> | |
#include <stdexcept> | |
#include <string> | |
#include <vector> | |
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; | |
}; | |
/* | |
* A QR Code symbol, which is a type of two-dimension barcode. | |
* Invented by Denso Wave and described in the ISO/IEC 18004 standard. | |
* Instances of this class represent an immutable square grid of black and white cells. | |
* The class provides static factory functions to create a QR Code from text or binary data. | |
* The class covers the QR Code Model 2 specification, supporting all versions (sizes) | |
* from 1 to 40, all 4 error correction levels, and 4 character encoding modes. | |
* | |
* Ways to create a QR Code object: | |
* - High level: Take the payload data and call QrCode::encodeText() or QrCode::encodeBinary(). | |
* - Mid level: Custom-make the list of segments and call QrCode::encodeSegments(). | |
* - Low level: Custom-make the array of data codeword bytes (including | |
* segment headers and final padding, excluding error correction codewords), | |
* supply the appropriate version number, and call the QrCode() constructor. | |
* (Note that all ways require supplying the desired error correction level.) | |
*/ | |
class QrCode final { | |
/*---- Public helper enumeration ----*/ | |
/* | |
* The error correction level in a QR Code symbol. | |
*/ | |
public: enum class Ecc { | |
LOW = 0 , // The QR Code can tolerate about 7% erroneous codewords | |
MEDIUM , // The QR Code can tolerate about 15% erroneous codewords | |
QUARTILE, // The QR Code can tolerate about 25% erroneous codewords | |
HIGH , // The QR Code can tolerate about 30% erroneous codewords | |
}; | |
// Returns a value in the range 0 to 3 (unsigned 2-bit integer). | |
private: static int getFormatBits(Ecc ecl); | |
/*---- Static factory functions (high level) ----*/ | |
/* | |
* Returns a QR Code representing the given Unicode text string at the given 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); | |
/* | |
* Returns a QR Code representing the given binary data 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); | |
/*---- Static factory functions (mid level) ----*/ | |
/* | |
* Returns a QR Code representing the given segments with the given encoding parameters. | |
* The smallest possible QR Code version within the given range is automatically | |
* chosen for the output. Iff boostEcl is true, then the ECC level of the result | |
* may be higher than the ecl argument if it can be done without increasing the | |
* version. The mask number is either between 0 to 7 (inclusive) to force that | |
* mask, or -1 to automatically choose an appropriate mask (which may be slow). | |
* This function allows the user to create a custom sequence of segments that switches | |
* between modes (such as alphanumeric and byte) to encode text in less space. | |
* This is a mid-level API; the high-level API is encodeText() and encodeBinary(). | |
*/ | |
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 | |
/*---- Instance fields ----*/ | |
// Immutable scalar parameters: | |
/* The version number of this QR Code, which is between 1 and 40 (inclusive). | |
* This determines the size of this barcode. */ | |
private: int version; | |
/* The width and height of this QR Code, measured in modules, between | |
* 21 and 177 (inclusive). This is equal to version * 4 + 17. */ | |
private: int size; | |
/* The error correction level used in this QR Code. */ | |
private: Ecc errorCorrectionLevel; | |
/* The index of the mask pattern used in this QR Code, which is between 0 and 7 (inclusive). | |
* Even if a QR Code is created with automatic masking requested (mask = -1), | |
* the resulting object still has a mask value between 0 and 7. */ | |
private: int mask; | |
// Private grids of modules/pixels, with dimensions of size*size: | |
// The modules of this QR Code (false = white, true = black). | |
// Immutable after constructor finishes. Accessed through getModule(). | |
private: std::vector<std::vector<bool> > modules; | |
// Indicates function modules that are not subjected to masking. Discarded when constructor finishes. | |
private: std::vector<std::vector<bool> > isFunction; | |
/*---- Constructor (low level) ----*/ | |
/* | |
* Creates a new QR Code with the given version number, | |
* error correction level, data codeword bytes, and mask number. | |
* This is a low-level API that most users should not use directly. | |
* A mid-level API is the encodeSegments() function. | |
*/ | |
public: QrCode(int ver, Ecc ecl, const std::vector<std::uint8_t> &dataCodewords, int msk); | |
/*---- Public instance methods ----*/ | |
/* | |
* Returns this QR Code's version, in the range [1, 40]. | |
*/ | |
public: int getVersion() const; | |
/* | |
* Returns this QR Code's size, in the range [21, 177]. | |
*/ | |
public: int getSize() const; | |
/* | |
* Returns this QR Code's error correction level. | |
*/ | |
public: Ecc getErrorCorrectionLevel() const; | |
/* | |
* Returns this QR Code's mask, in the range [0, 7]. | |
*/ | |
public: int getMask() const; | |
/* | |
* Returns the color of the module (pixel) at the given coordinates, which is 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; | |
/* | |
* Returns a string of SVG code for an image depicting this QR Code, with the given number | |
* of border modules. The string always uses Unix newlines (\n), regardless of the platform. | |
*/ | |
public: std::string toSvgString(int border) const; | |
/*---- Private helper methods for constructor: Drawing function modules ----*/ | |
// Reads this object's version field, and draws and marks all 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 msk); | |
// Draws two copies of the version bits (with its own error correction code), | |
// based on this object's version field, iff 7 <= version <= 40. | |
private: void drawVersion(); | |
// Draws a 9*9 finder pattern including the border separator, | |
// with the center module at (x, y). Modules can be out of bounds. | |
private: void drawFinderPattern(int x, int y); | |
// Draws a 5*5 alignment pattern, with the center module | |
// at (x, y). All modules must be in bounds. | |
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 bounds. | |
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> addEccAndInterleave(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. Function modules need to be marked off before this is called. | |
private: void drawCodewords(const std::vector<std::uint8_t> &data); | |
// XORs the codeword modules in this QR Code with the given mask pattern. | |
// The function modules must be marked and the codeword bits must be drawn | |
// before masking. Due to the arithmetic of XOR, calling applyMask() with | |
// the same mask value a second time will undo the mask. A final well-formed | |
// QR Code needs exactly one (not zero, two, etc.) mask applied. | |
private: void applyMask(int msk); | |
// 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 helper functions ----*/ | |
// Returns an ascending list of positions of alignment patterns for this version number. | |
// Each position is in the range [0,177), and are used on both the x and y axes. | |
// This could be implemented as lookup table of 40 variable-length lists of unsigned bytes. | |
private: std::vector<int> getAlignmentPatternPositions() const; | |
// 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); | |
// Returns a Reed-Solomon ECC generator polynomial for the given degree. This could be | |
// implemented as a lookup table over all possible parameter values, instead of as an algorithm. | |
private: static std::vector<std::uint8_t> reedSolomonComputeDivisor(int degree); | |
// Returns the Reed-Solomon error correction codeword for the given data and divisor polynomials. | |
private: static std::vector<std::uint8_t> reedSolomonComputeRemainder(const std::vector<std::uint8_t> &data, const std::vector<std::uint8_t> &divisor); | |
// 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 reedSolomonMultiply(std::uint8_t x, std::uint8_t y); | |
// Can only be called immediately after a white run is added, and | |
// returns either 0, 1, or 2. A helper function for getPenaltyScore(). | |
private: int finderPenaltyCountPatterns(const std::array<int,7> &runHistory) const; | |
// Must be called at the end of a line (row or column) of modules. A helper function for getPenaltyScore(). | |
private: int finderPenaltyTerminateAndCount(bool currentRunColor, int currentRunLength, std::array<int,7> &runHistory) const; | |
// Pushes the given value to the front and drops the last value. A helper function for getPenaltyScore(). | |
private: void finderPenaltyAddHistory(int currentRunLength, std::array<int,7> &runHistory) const; | |
// Returns true iff the i'th bit of x is set to 1. | |
private: static bool getBit(long x, int i); | |
/*---- Constants and tables ----*/ | |
// The minimum version number supported in the QR Code Model 2 standard. | |
public: static constexpr int MIN_VERSION = 1; | |
// The maximum version number supported in the QR Code Model 2 standard. | |
public: static constexpr int MAX_VERSION = 40; | |
// 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]; | |
}; | |
/*---- Public exception class ----*/ | |
/* | |
* Thrown when the supplied data does not fit any QR Code version. Ways to handle this exception include: | |
* - Decrease the error correction level if it was greater than Ecc::LOW. | |
* - If the encodeSegments() function was called with a maxVersion argument, then increase | |
* it if it was less than QrCode::MAX_VERSION. (This advice does not apply to the other | |
* factory functions because they search all versions up to QrCode::MAX_VERSION.) | |
* - Split the text data into better or optimal segments in order to reduce the number of bits required. | |
* - Change the text or binary data to be shorter. | |
* - Change the text to fit the character set of a particular segment mode (e.g. alphanumeric). | |
* - Propagate the error upward to the caller/user. | |
*/ | |
class data_too_long : public std::length_error { | |
public: explicit data_too_long(const std::string &msg); | |
}; | |
/* | |
* An appendable sequence of bits (0s and 1s). Mainly used by QrSegment. | |
*/ | |
class BitBuffer final : public std::vector<bool> { | |
/*---- Constructor ----*/ | |
// Creates an empty bit buffer (length 0). | |
public: BitBuffer(); | |
/*---- Method ----*/ | |
// Appends the given number of low-order bits of the given value | |
// to this buffer. Requires 0 <= len <= 31 and val < 2^len. | |
public: void appendBits(std::uint32_t val, int len); | |
}; | |
} |