/* * 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 #include #include #ifdef __cplusplus extern "C" { #endif /* * This library creates QR Code symbols, which is a type of two-dimension barcode. * Invented by Denso Wave and described in the ISO/IEC 18004 standard. * A QR Code structure is an immutable square grid of dark and light cells. * The library provides functions to create a QR Code from text or binary data. * The library 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 qrcodegen_encodeText() or qrcodegen_encodeBinary(). * - Low level: Custom-make the list of segments and call * qrcodegen_encodeSegments() or qrcodegen_encodeSegmentsAdvanced(). * (Note that all ways require supplying the desired error correction level and various byte buffers.) */ /*---- Enum and struct types----*/ /* * The error correction level in a QR Code symbol. */ enum qrcodegen_Ecc { // Must be declared in ascending order of error protection // so that an internal qrcodegen function works properly qrcodegen_Ecc_LOW = 0 , // The QR Code can tolerate about 7% erroneous codewords qrcodegen_Ecc_MEDIUM , // The QR Code can tolerate about 15% erroneous codewords qrcodegen_Ecc_QUARTILE, // The QR Code can tolerate about 25% erroneous codewords qrcodegen_Ecc_HIGH , // The QR Code can tolerate about 30% erroneous codewords }; /* * The mask pattern used in a QR Code symbol. */ enum qrcodegen_Mask { // A special value to tell the QR Code encoder to // automatically select an appropriate mask pattern qrcodegen_Mask_AUTO = -1, // The eight actual mask patterns qrcodegen_Mask_0 = 0, qrcodegen_Mask_1, qrcodegen_Mask_2, qrcodegen_Mask_3, qrcodegen_Mask_4, qrcodegen_Mask_5, qrcodegen_Mask_6, qrcodegen_Mask_7, }; /* * Describes how a segment's data bits are interpreted. */ enum qrcodegen_Mode { qrcodegen_Mode_NUMERIC = 0x1, qrcodegen_Mode_ALPHANUMERIC = 0x2, qrcodegen_Mode_BYTE = 0x4, qrcodegen_Mode_KANJI = 0x8, qrcodegen_Mode_ECI = 0x7, }; /* * A segment of character/binary/control data in a QR Code symbol. * The mid-level way to create a segment is to take the payload data * and call a factory function such as qrcodegen_makeNumeric(). * The low-level way to create a segment is to custom-make the bit buffer * and initialize a qrcodegen_Segment struct with appropriate values. * 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. * Moreover, the maximum allowed bit length is 32767 because * the largest QR Code (version 40) has 31329 modules. */ struct qrcodegen_Segment { // The mode indicator of this segment. enum qrcodegen_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. int numChars; // The data bits of this segment, packed in bitwise big endian. // Can be null if the bit length is zero. uint8_t *data; // The number of valid data bits used in the buffer. Requires // 0 <= bitLength <= 32767, and bitLength <= (capacity of data array) * 8. // The character count (numChars) must agree with the mode and the bit buffer length. int bitLength; }; /*---- Macro constants and functions ----*/ #define qrcodegen_VERSION_MIN 1 // The minimum version number supported in the QR Code Model 2 standard #define qrcodegen_VERSION_MAX 40 // The maximum version number supported in the QR Code Model 2 standard // Calculates the number of bytes needed to store any QR Code up to and including the given version number, // as a compile-time constant. For example, 'uint8_t buffer[qrcodegen_BUFFER_LEN_FOR_VERSION(25)];' // can store any single QR Code from version 1 to 25 (inclusive). The result fits in an int (or int16). // Requires qrcodegen_VERSION_MIN <= n <= qrcodegen_VERSION_MAX. #define qrcodegen_BUFFER_LEN_FOR_VERSION(n) ((((n) * 4 + 17) * ((n) * 4 + 17) + 7) / 8 + 1) // The worst-case number of bytes needed to store one QR Code, up to and including // version 40. This value equals 3918, which is just under 4 kilobytes. // Use this more convenient value to avoid calculating tighter memory bounds for buffers. #define qrcodegen_BUFFER_LEN_MAX qrcodegen_BUFFER_LEN_FOR_VERSION(qrcodegen_VERSION_MAX) /*---- Functions (high level) to generate QR Codes ----*/ /* * Encodes the given text string to a QR Code, returning true if successful. * If the data is too long to fit in any version in the given range * at the given ECC level, then false is returned. * - The input text must be encoded in UTF-8 and contain no NULs. * - The variables ecl and mask must correspond to enum constant values. * - Requires 1 <= minVersion <= maxVersion <= 40. * - About the arrays, letting len = qrcodegen_BUFFER_LEN_FOR_VERSION(maxVersion): * - Before calling the function: * - The array ranges tempBuffer[0 : len] and qrcode[0 : len] must allow * reading and writing; hence each array must have a length of at least len. * - The two ranges must not overlap (aliasing). * - The initial state of both ranges can be uninitialized * because the function always writes before reading. * - After the function returns: * - Both ranges have no guarantee on which elements are initialized and what values are stored. * - tempBuffer contains no useful data and should be treated as entirely uninitialzed. * - If successful, qrcode can be passed into qrcodegen_getSize() and qrcodegen_getModule(). * - If successful, the resulting QR Code may use numeric, * alphanumeric, or byte mode to encode the text. * - In the most optimistic case, a QR Code at version 40 with low ECC * can hold any UTF-8 string up to 2953 bytes, or any alphanumeric string * up to 4296 characters, or any digit string up to 7089 characters. * These numbers represent the hard upper limit of the QR Code standard. * - Please consult the QR Code specification for information on * data capacities per version, ECC level, and text encoding mode. */ bool qrcodegen_encodeText(const char *text, uint8_t tempBuffer[], uint8_t qrcode[], enum qrcodegen_Ecc ecl, int minVersion, int maxVersion, enum qrcodegen_Mask mask, bool boostEcl); /* * Encodes the given binary data to a QR Code, returning true if successful. * If the data is too long to fit in any version in the given range * at the given ECC level, then false is returned. * - The variables ecl and mask must correspond to enum constant values. * - Requires 1 <= minVersion <= maxVersion <= 40. * - About the arrays, letting len = qrcodegen_BUFFER_LEN_FOR_VERSION(maxVersion): * - Before calling the function: * - The array ranges dataAndTemp[0 : len] and qrcode[0 : len] must allow * reading and writing; hence each array must have a length of at least len. * - The two ranges must not overlap (aliasing). * - The input array range dataAndTemp[0 : dataLen] should normally be * valid UTF-8 text, but is not required by the QR Code standard. * - The initial state of dataAndTemp[dataLen : len] and qrcode[0 : len] * can be uninitialized because the function always writes before reading. * - After the function returns: * - Both ranges have no guarantee on which elements are initialized and what values are stored. * - dataAndTemp contains no useful data and should be treated as entirely uninitialzed. * - If successful, qrcode can be passed into qrcodegen_getSize() and qrcodegen_getModule(). * - If successful, the resulting QR Code will use byte mode to encode the data. * - In the most optimistic case, a QR Code at version 40 with low ECC can hold any byte * sequence up to length 2953. This is the hard upper limit of the QR Code standard. * - Please consult the QR Code specification for information on * data capacities per version, ECC level, and text encoding mode. */ bool qrcodegen_encodeBinary(uint8_t dataAndTemp[], size_t dataLen, uint8_t qrcode[], enum qrcodegen_Ecc ecl, int minVersion, int maxVersion, enum qrcodegen_Mask mask, bool boostEcl); /*---- Functions (low level) to generate QR Codes ----*/ /* * Renders a QR Code representing the given segments at the given error correction level. * The smallest possible QR Code version is automatically chosen for the output. Returns true if * QR Code creation succeeded, or false if the data is too long to fit in any version. The ECC level * of the result may be higher than the ecl argument if it can be done without increasing the version. * 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 low-level API; the high-level API is qrcodegen_encodeText() and qrcodegen_encodeBinary(). * To save memory, the segments' data buffers can alias/overlap tempBuffer, and will * result in them being clobbered, but the QR Code output will still be correct. * But the qrcode array must not overlap tempBuffer or any segment's data buffer. */ bool qrcodegen_encodeSegments(const struct qrcodegen_Segment segs[], size_t len, enum qrcodegen_Ecc ecl, uint8_t tempBuffer[], uint8_t qrcode[]); /* * Renders a QR Code representing the given segments with the given encoding parameters. * Returns true if QR Code creation succeeded, or false if the data is too long to fit in the range of versions. * 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 is either between qrcodegen_Mask_0 to 7 to force that mask, or * qrcodegen_Mask_AUTO 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 low-level API; the high-level API is qrcodegen_encodeText() and qrcodegen_encodeBinary(). * To save memory, the segments' data buffers can alias/overlap tempBuffer, and will * result in them being clobbered, but the QR Code output will still be correct. * But the qrcode array must not overlap tempBuffer or any segment's data buffer. */ bool qrcodegen_encodeSegmentsAdvanced(const struct qrcodegen_Segment segs[], size_t len, enum qrcodegen_Ecc ecl, int minVersion, int maxVersion, enum qrcodegen_Mask mask, bool boostEcl, uint8_t tempBuffer[], uint8_t qrcode[]); /* * 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. */ bool qrcodegen_isNumeric(const char *text); /* * 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. */ bool qrcodegen_isAlphanumeric(const char *text); /* * Returns the number of bytes (uint8_t) needed for the data buffer of a segment * containing the given number of characters using the given mode. Notes: * - Returns SIZE_MAX on failure, i.e. numChars > INT16_MAX or the internal * calculation of the number of needed bits exceeds INT16_MAX (i.e. 32767). * - Otherwise, all valid results are in the range [0, ceil(INT16_MAX / 8)], i.e. at most 4096. * - It is okay for the user to allocate more bytes for the buffer than needed. * - For byte mode, numChars measures the number of bytes, not Unicode code points. * - For ECI mode, numChars must be 0, and the worst-case number of bytes is returned. * An actual ECI segment can have shorter data. For non-ECI modes, the result is exact. */ size_t qrcodegen_calcSegmentBufferSize(enum qrcodegen_Mode mode, size_t numChars); /* * Returns a segment representing the given binary data encoded in * byte mode. All input byte arrays are acceptable. Any text string * can be converted to UTF-8 bytes and encoded as a byte mode segment. */ struct qrcodegen_Segment qrcodegen_makeBytes(const uint8_t data[], size_t len, uint8_t buf[]); /* * Returns a segment representing the given string of decimal digits encoded in numeric mode. */ struct qrcodegen_Segment qrcodegen_makeNumeric(const char *digits, uint8_t buf[]); /* * 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. */ struct qrcodegen_Segment qrcodegen_makeAlphanumeric(const char *text, uint8_t buf[]); /* * Returns a segment representing an Extended Channel Interpretation * (ECI) designator with the given assignment value. */ struct qrcodegen_Segment qrcodegen_makeEci(long assignVal, uint8_t buf[]); /*---- Functions to extract raw data from QR Codes ----*/ /* * Returns the side length of the given QR Code, assuming that encoding succeeded. * The result is in the range [21, 177]. Note that the length of the array buffer * is related to the side length - every 'uint8_t qrcode[]' must have length at least * qrcodegen_BUFFER_LEN_FOR_VERSION(version), which equals ceil(size^2 / 8 + 1). */ int qrcodegen_getSize(const uint8_t qrcode[]); /* * Returns the color of the module (pixel) at the given coordinates, which is false * for light or true for dark. The top left corner has the coordinates (x=0, y=0). * If the given coordinates are out of bounds, then false (light) is returned. */ bool qrcodegen_getModule(const uint8_t qrcode[], int x, int y); #ifdef __cplusplus } #endif