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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 <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 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 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, int 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