/**
 * qrencode - QR Code encoder
 *
 * Copyright (C) 2006-2018, 2020 Kentaro Fukuchi <kentaro@fukuchi.org>
 * Copyright (C) 2026 Project Tick
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 */

/** \mainpage
 * Libqrencode is a library for encoding data in a QR Code symbol, a kind of 2D
 * symbology.
 *
 * \section encoding Encoding
 *
 * There are two methods to encode data: <b>encoding a string/data</b> or
 * <b>encoding a structured data</b>.
 *
 * \subsection encoding-string Encoding a string/data
 * You can encode a string by calling QRcode_encodeString().
 * The given string is parsed automatically and encoded. If you want to encode
 * data that can be represented as a C string style (NUL terminated), you can
 * simply use this way.
 *
 * If the input data contains Kanji (Shift-JIS) characters and you want to
 * encode them as Kanji in QR Code, you should give QR_MODE_KANJI as a hint.
 * Otherwise, all of non-alphanumeric characters are encoded as 8-bit data.
 * If you want to encode a whole string in 8-bit mode, you can use
 * QRcode_encodeString8bit() instead.
 *
 * Please note that a C string can not contain NUL characters. If your data
 * contains NUL, you must use QRcode_encodeData().
 *
 * \subsection encoding-input Encoding a structured data
 * You can construct a structured input data manually. If the structure of the
 * input data is known, you can use this method.
 * At first, create a ::QRinput object by QRinput_new(). Then add input data
 * to the QRinput object by QRinput_append(). Finally call QRcode_encodeInput()
 * to encode the QRinput data.
 * You can reuse the QRinput object again to encode it in other symbols with
 * different parameters.
 *
 * \section result Result
 * The encoded symbol is generated as a ::QRcode object. It will contain its
 * version number, the width of the symbol, and an array represents the symbol.
 * See ::QRcode for the details. You can free the object by QRcode_free().
 *
 * Please note that the version of the result may be larger than specified.
 * In such cases, the input data would be too large to be encoded in a
 * symbol of the specified version.
 *
 * The following code snippet demonstrates how to use the obtained object:
 *
 * \code
 * QRcode *qrcode;
 *
 * qrcode = QRcode_encodeString("TEST", 0, QR_ECLEVEL_M, QR_MODE_8, 1);
 * if(qrcode == NULL) abort();
 *
 * for(int y = 0; y < qrcode->width; y++) {
 *     for(int x = 0; x < qrcode->width; x++) {
 *         if(qrcode->data[y * qrcode->width + x] & 1) {
 *             draw_black_dot(x, y);
 *         } else {
 *             draw_white_dot(x, y);
 *         }
 *     }
 * }
 *
 * QRcode_free(qrcode);
 * \endcode
 *
 * \section structured Structured append
 * Libqrencode can generate "Structured-appended" symbols that enable to split
 * a large data set into multiple QR codes. A QR code reader concatenates
 * multiple QR code symbols into a string.
 * Just like QRcode_encodeString(), you can use QRcode_encodeStringStructured()
 * to generate structured-appended symbols. This function returns an instance
 * of ::QRcode_List. The returned list is a singly-linked list of QRcode: you
 * can retrieve each QR code in this way:
 *
 * \code
 * QRcode_List *qrcodes;
 * QRcode_List *entry;
 * QRcode *qrcode;
 *
 * qrcodes = QRcode_encodeStringStructured(...);
 * entry = qrcodes;
 * while(entry != NULL) {
 *     qrcode = entry->code;
 *     // do something
 *     entry = entry->next;
 * }
 * QRcode_List_free(entry);
 * \endcode
 *
 * Instead of using auto-parsing functions, you can construct your own
 * structured input. At first, instantiate an object of ::QRinput_Struct
 * by calling QRinput_Struct_new(). This object can hold multiple ::QRinput,
 * and one QR code is generated for a ::QRinput.
 * QRinput_Struct_appendInput() appends a ::QRinput to a ::QRinput_Struct
 * object. In order to generate structured-appended symbols, it is required to
 * embed headers to each symbol. You can use
 * QRinput_Struct_insertStructuredAppendHeaders() to insert appropriate
 * headers to each symbol. You should call this function just once before
 * encoding symbols.
 */

#ifndef QRENCODE_H
#define QRENCODE_H

#if defined(__cplusplus)
extern "C" {
#endif

/**
 * Encoding mode.
 */
typedef enum {
	QR_MODE_NUL = -1,   ///< Terminator (NUL character). Internal use only
	QR_MODE_NUM = 0,    ///< Numeric mode
	QR_MODE_AN,         ///< Alphabet-numeric mode
	QR_MODE_8,          ///< 8-bit data mode
	QR_MODE_KANJI,      ///< Kanji (shift-jis) mode
	QR_MODE_STRUCTURE,  ///< Internal use only
	QR_MODE_ECI,        ///< ECI mode
	QR_MODE_FNC1FIRST,  ///< FNC1, first position
	QR_MODE_FNC1SECOND, ///< FNC1, second position
} QRencodeMode;

/**
 * Level of error correction.
 */
typedef enum {
	QR_ECLEVEL_L = 0, ///< lowest
	QR_ECLEVEL_M,
	QR_ECLEVEL_Q,
	QR_ECLEVEL_H      ///< highest
} QRecLevel;

/**
 * Maximum version (size) of QR-code symbol.
 */
#define QRSPEC_VERSION_MAX 40

/**
 * Maximum version (size) of QR-code symbol.
 */
#define MQRSPEC_VERSION_MAX 4


/******************************************************************************
 * Input data (qrinput.c)
 *****************************************************************************/

/**
 * Singly linked list to contain input strings. An instance of this class
 * contains its version and error correction level too. It is required to
 * set them by QRinput_setVersion() and QRinput_setErrorCorrectionLevel(),
 * or use QRinput_new2() to instantiate an object.
 */
typedef struct _QRinput QRinput;

/**
 * Instantiate an input data object. The version is set to 0 (auto-select)
 * and the error correction level is set to QR_ECLEVEL_L.
 * @return an input object (initialized). On error, NULL is returned and errno
 *         is set to indicate the error.
 * @throw ENOMEM unable to allocate memory.
 */
extern QRinput *QRinput_new(void);

/**
 * Instantiate an input data object.
 * @param version version number.
 * @param level Error correction level.
 * @return an input object (initialized). On error, NULL is returned and errno
 *         is set to indicate the error.
 * @throw ENOMEM unable to allocate memory for input objects.
 * @throw EINVAL invalid arguments.
 */
extern QRinput *QRinput_new2(int version, QRecLevel level);

/**
 * Instantiate an input data object. Object's Micro QR Code flag is set.
 * Unlike with full-sized QR Code, version number must be specified (>0).
 * @param version version number (1--4).
 * @param level Error correction level.
 * @return an input object (initialized). On error, NULL is returned and errno
 *         is set to indicate the error.
 * @throw ENOMEM unable to allocate memory for input objects.
 * @throw EINVAL invalid arguments.
 */
extern QRinput *QRinput_newMQR(int version, QRecLevel level);

/**
 * Append data to an input object.
 * The data is copied and appended to the input object.
 * @param input input object.
 * @param mode encoding mode.
 * @param size size of data (byte).
 * @param data a pointer to the memory area of the input data.
 * @retval 0 success.
 * @retval -1 an error occurred and errno is set to indicate the error.
 *            See Execptions for the details.
 * @throw ENOMEM unable to allocate memory.
 * @throw EINVAL input data is invalid.
 *
 */
extern int QRinput_append(QRinput *input, QRencodeMode mode, int size, const unsigned char *data);

/**
 * Append ECI header.
 * @param input input object.
 * @param ecinum ECI indicator number (0 - 999999)
 * @retval 0 success.
 * @retval -1 an error occurred and errno is set to indicate the error.
 *            See Execptions for the details.
 * @throw ENOMEM unable to allocate memory.
 * @throw EINVAL input data is invalid.
 *
 */
extern int QRinput_appendECIheader(QRinput *input, unsigned int ecinum);

/**
 * Get current version.
 * @param input input object.
 * @return current version.
 */
extern int QRinput_getVersion(QRinput *input);

/**
 * Set version of the QR code that is to be encoded.
 * This function cannot be applied to Micro QR Code.
 * @param input input object.
 * @param version version number (0 = auto)
 * @retval 0 success.
 * @retval -1 invalid argument.
 */
extern int QRinput_setVersion(QRinput *input, int version);

/**
 * Get current error correction level.
 * @param input input object.
 * @return Current error correcntion level.
 */
extern QRecLevel QRinput_getErrorCorrectionLevel(QRinput *input);

/**
 * Set error correction level of the QR code that is to be encoded.
 * This function cannot be applied to Micro QR Code.
 * @param input input object.
 * @param level Error correction level.
 * @retval 0 success.
 * @retval -1 invalid argument.
 */
extern int QRinput_setErrorCorrectionLevel(QRinput *input, QRecLevel level);

/**
 * Set version and error correction level of the QR code at once.
 * This function is recommened for Micro QR Code.
 * @param input input object.
 * @param version version number (0 = auto)
 * @param level Error correction level.
 * @retval 0 success.
 * @retval -1 invalid argument.
 */
extern int QRinput_setVersionAndErrorCorrectionLevel(QRinput *input, int version, QRecLevel level);

/**
 * Free the input object.
 * All of data chunks in the input object are freed too.
 * @param input input object.
 */
extern void QRinput_free(QRinput *input);

/**
 * Validate the input data.
 * @param mode encoding mode.
 * @param size size of data (byte).
 * @param data a pointer to the memory area of the input data.
 * @retval 0 success.
 * @retval -1 invalid arguments.
 */
extern int QRinput_check(QRencodeMode mode, int size, const unsigned char *data);

/**
 * Set of QRinput for structured symbols.
 */
typedef struct _QRinput_Struct QRinput_Struct;

/**
 * Instantiate a set of input data object.
 * @return an instance of QRinput_Struct. On error, NULL is returned and errno
 *         is set to indicate the error.
 * @throw ENOMEM unable to allocate memory.
 */
extern QRinput_Struct *QRinput_Struct_new(void);

/**
 * Set parity of structured symbols.
 * @param s structured input object.
 * @param parity parity of s.
 */
extern void QRinput_Struct_setParity(QRinput_Struct *s, unsigned char parity);

/**
 * Append a QRinput object to the set. QRinput created by QRinput_newMQR()
 * will be rejected.
 * @warning never append the same QRinput object twice or more.
 * @param s structured input object.
 * @param input an input object.
 * @retval >0 number of input objects in the structure.
 * @retval -1 an error occurred. See Exceptions for the details.
 * @throw ENOMEM unable to allocate memory.
 * @throw EINVAL invalid arguments.
 */
extern int QRinput_Struct_appendInput(QRinput_Struct *s, QRinput *input);

/**
 * Free all of QRinput in the set.
 * @param s a structured input object.
 */
extern void QRinput_Struct_free(QRinput_Struct *s);

/**
 * Split a QRinput to QRinput_Struct. It calculates a parity, set it, then
 * insert structured-append headers. QRinput created by QRinput_newMQR() will
 * be rejected.
 * @param input input object. Version number and error correction level must be
 *        set.
 * @return a set of input data. On error, NULL is returned, and errno is set
 *         to indicate the error. See Exceptions for the details.
 * @throw ERANGE input data is too large.
 * @throw EINVAL invalid input data.
 * @throw ENOMEM unable to allocate memory.
 */
extern QRinput_Struct *QRinput_splitQRinputToStruct(QRinput *input);

/**
 * Insert structured-append headers to the input structure. It calculates
 * a parity and set it if the parity is not set yet.
 * @param s input structure
 * @retval 0 success.
 * @retval -1 an error occurred and errno is set to indicate the error.
 *            See Execptions for the details.
 * @throw EINVAL invalid input object.
 * @throw ENOMEM unable to allocate memory.
 */
extern int QRinput_Struct_insertStructuredAppendHeaders(QRinput_Struct *s);

/**
 * Set FNC1-1st position flag.
 */
extern int QRinput_setFNC1First(QRinput *input);

/**
 * Set FNC1-2nd position flag and application identifier.
 */
extern int QRinput_setFNC1Second(QRinput *input, unsigned char appid);

/******************************************************************************
 * QRcode output (qrencode.c)
 *****************************************************************************/

/**
 * QRcode class.
 * Symbol data is represented as an array contains width*width uchars.
 * Each uchar represents a module (dot). If the less significant bit of
 * the uchar is 1, the corresponding module is black. The other bits are
 * meaningless for usual applications, but here its specification is described.
 *
 * @verbatim
   MSB 76543210 LSB
       |||||||`- 1=black/0=white
       ||||||`-- 1=ecc/0=data code area
       |||||`--- format information
       ||||`---- version information
       |||`----- timing pattern
       ||`------ alignment pattern
       |`------- finder pattern and separator
       `-------- non-data modules (format, timing, etc.)
   @endverbatim
 *
 * See \ref result section for a sample code snippet that shows how to use the
 * obtained QRcode object.
 */
typedef struct {
	int version;         ///< version of the symbol
	int width;           ///< width of the symbol
	unsigned char *data; ///< symbol data
} QRcode;

/**
 * Singly-linked list of QRcode. Used to represent a structured symbols.
 * A list is terminated with NULL.
 */
typedef struct _QRcode_List {
	QRcode *code;
	struct _QRcode_List *next;
} QRcode_List;

/**
 * Create a symbol from the input data.
 * @warning This function is THREAD UNSAFE when pthread is disabled.
 * @param input input data.
 * @return an instance of QRcode class. The version of the result QRcode may
 *         be larger than the designated version. On error, NULL is returned,
 *         and errno is set to indicate the error. See Exceptions for the
 *         details.
 * @throw EINVAL invalid input object.
 * @throw ENOMEM unable to allocate memory for input objects.
 */
extern QRcode *QRcode_encodeInput(QRinput *input);

/**
 * Create a symbol from the string. The library automatically parses the input
 * string and encodes in a QR Code symbol.
 * @warning This function is THREAD UNSAFE when pthread is disabled.
 * @param string input string. It must be NUL terminated.
 * @param version version of the symbol. If 0, the library chooses the minimum
 *                version for the given input data.
 * @param level error correction level.
 * @param hint tell the library how Japanese Kanji characters should be
 *             encoded. If QR_MODE_KANJI is given, the library assumes that the
 *             given string contains Shift-JIS characters and encodes them in
 *             Kanji-mode. If QR_MODE_8 is given, all non-alphanumerical
 *             characters will be encoded as is. If you want to embed UTF-8
 *             string, choose this. Other mode will cause EINVAL error.
 * @param casesensitive case-sensitive(1) or not(0).
 * @return an instance of QRcode class. The version of the result QRcode may
 *         be larger than the designated version. On error, NULL is returned,
 *         and errno is set to indicate the error. See Exceptions for the
 *         details.
 * @throw EINVAL invalid input object.
 * @throw ENOMEM unable to allocate memory for input objects.
 * @throw ERANGE input data is too large.
 */
extern QRcode *QRcode_encodeString(const char *string, int version, QRecLevel level, QRencodeMode hint, int casesensitive);

/**
 * Same to QRcode_encodeString(), but encode whole data in 8-bit mode.
 * @warning This function is THREAD UNSAFE when pthread is disabled.
 */
extern QRcode *QRcode_encodeString8bit(const char *string, int version, QRecLevel level);

/**
 * Micro QR Code version of QRcode_encodeString().
 * @warning This function is THREAD UNSAFE when pthread is disabled.
 */
extern QRcode *QRcode_encodeStringMQR(const char *string, int version, QRecLevel level, QRencodeMode hint, int casesensitive);

/**
 * Micro QR Code version of QRcode_encodeString8bit().
 * @warning This function is THREAD UNSAFE when pthread is disabled.
 */
extern QRcode *QRcode_encodeString8bitMQR(const char *string, int version, QRecLevel level);

/**
 * Encode byte stream (may include '\0') in 8-bit mode.
 * @warning This function is THREAD UNSAFE when pthread is disabled.
 * @param size size of the input data.
 * @param data input data.
 * @param version version of the symbol. If 0, the library chooses the minimum
 *                version for the given input data.
 * @param level error correction level.
 * @throw EINVAL invalid input object.
 * @throw ENOMEM unable to allocate memory for input objects.
 * @throw ERANGE input data is too large.
 */
extern QRcode *QRcode_encodeData(int size, const unsigned char *data, int version, QRecLevel level);

/**
 * Micro QR Code version of QRcode_encodeData().
 * @warning This function is THREAD UNSAFE when pthread is disabled.
 */
extern QRcode *QRcode_encodeDataMQR(int size, const unsigned char *data, int version, QRecLevel level);

/**
 * Free the instance of QRcode class.
 * @param qrcode an instance of QRcode class.
 */
extern void QRcode_free(QRcode *qrcode);

/**
 * Create structured symbols from the input data.
 * @warning This function is THREAD UNSAFE when pthread is disabled.
 * @param s input data, structured.
 * @return a singly-linked list of QRcode.
 */
extern QRcode_List *QRcode_encodeInputStructured(QRinput_Struct *s);

/**
 * Create structured symbols from the string. The library automatically parses
 * the input string and encodes in a QR Code symbol.
 * @warning This function is THREAD UNSAFE when pthread is disabled.
 * @param string input string. It must be NUL terminated.
 * @param version version of the symbol.
 * @param level error correction level.
 * @param hint tell the library how Japanese Kanji characters should be
 *             encoded. If QR_MODE_KANJI is given, the library assumes that the
 *             given string contains Shift-JIS characters and encodes them in
 *             Kanji-mode. If QR_MODE_8 is given, all of non-alphanumerical
 *             characters will be encoded as is. If you want to embed UTF-8
 *             string, choose this. Other mode will cause EINVAL error.
 * @param casesensitive case-sensitive(1) or not(0).
 * @return a singly-linked list of QRcode. On error, NULL is returned, and
 *         errno is set to indicate the error. See Exceptions for the details.
 * @throw EINVAL invalid input object.
 * @throw ENOMEM unable to allocate memory for input objects.
 */
extern QRcode_List *QRcode_encodeStringStructured(const char *string, int version, QRecLevel level, QRencodeMode hint, int casesensitive);

/**
 * Same to QRcode_encodeStringStructured(), but encode whole data in 8-bit mode.
 * @warning This function is THREAD UNSAFE when pthread is disabled.
 */
extern QRcode_List *QRcode_encodeString8bitStructured(const char *string, int version, QRecLevel level);

/**
 * Create structured symbols from byte stream (may include '\0'). Wholde data
 * are encoded in 8-bit mode.
 * @warning This function is THREAD UNSAFE when pthread is disabled.
 * @param size size of the input data.
 * @param data input dat.
 * @param version version of the symbol.
 * @param level error correction level.
 * @return a singly-linked list of QRcode. On error, NULL is returned, and
 *         errno is set to indicate the error. See Exceptions for the details.
 * @throw EINVAL invalid input object.
 * @throw ENOMEM unable to allocate memory for input objects.
 */
extern QRcode_List *QRcode_encodeDataStructured(int size, const unsigned char *data, int version, QRecLevel level);

/**
 * Return the number of symbols included in a QRcode_List.
 * @param qrlist a head entry of a QRcode_List.
 * @return number of symbols in the list.
 */
extern int QRcode_List_size(QRcode_List *qrlist);

/**
 * Free the QRcode_List.
 * @param qrlist a head entry of a QRcode_List.
 */
extern void QRcode_List_free(QRcode_List *qrlist);


/******************************************************************************
 * System utilities
 *****************************************************************************/

/**
 * Return the major.minor.micro version numbers that identifies the
 * library version.
 * @param major_version a pointer where to store the major version number
 * @param minor_version a pointer where to store the minor version number
 * @param micro_version a pointer where to store the micro version number
 */
extern void QRcode_APIVersion(int *major_version, int *minor_version, int *micro_version);

/**
 * Return a string that identifies the library version.
 * @return a string identifies the library version. The string is held by the
 * library. Do NOT free it.
 */
extern char *QRcode_APIVersionString(void);

/**
 * @deprecated
 */
#ifndef _MSC_VER
extern void QRcode_clearCache(void) __attribute__ ((deprecated));
#else
extern void QRcode_clearCache(void);
#endif

#if defined(__cplusplus)
}
#endif

#endif /* QRENCODE_H */
