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Diffstat (limited to 'main/qrcodegen.h')
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diff --git a/main/qrcodegen.h b/main/qrcodegen.h new file mode 100644 index 0000000..f76be20 --- /dev/null +++ b/main/qrcodegen.h @@ -0,0 +1,311 @@ +/* + * 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 <stdbool.h> +#include <stddef.h> +#include <stdint.h> + + +#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 black and white 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 encoding succeeded. + * 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. + * - The arrays tempBuffer and qrcode must each have a length + * of at least qrcodegen_BUFFER_LEN_FOR_VERSION(maxVersion). + * - After the function returns, tempBuffer contains no useful data. + * - 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 encoding succeeded. + * 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 array range dataAndTemp[0 : dataLen] should normally be + * valid UTF-8 text, but is not required by the QR Code standard. + * - The variables ecl and mask must correspond to enum constant values. + * - Requires 1 <= minVersion <= maxVersion <= 40. + * - The arrays dataAndTemp and qrcode must each have a length + * of at least qrcodegen_BUFFER_LEN_FOR_VERSION(maxVersion). + * - After the function returns, the contents of dataAndTemp may have changed, + * and does not represent useful data anymore. + * - 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 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); + + +/* + * 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); + + +/* + * 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 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 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. + */ +bool qrcodegen_getModule(const uint8_t qrcode[], int x, int y); + + +#ifdef __cplusplus +} +#endif |