From ae0fbaa89fad5cda832d29188bb76130510c8465 Mon Sep 17 00:00:00 2001 From: "Adam D. Ruppe" Date: Wed, 28 Jul 2021 22:23:24 -0400 Subject: [PATCH] initial commit --- qrcode.d | 1337 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 1337 insertions(+) create mode 100644 qrcode.d diff --git a/qrcode.d b/qrcode.d new file mode 100644 index 0000000..704855c --- /dev/null +++ b/qrcode.d @@ -0,0 +1,1337 @@ +/++ + This is a port of the C code from https://www.nayuki.io/page/qr-code-generator-library + + History: + Originally written in C by Project Nayuki. + + Ported to D by me on July 26, 2021 ++/ +/* + * 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. + */ +module arsd.qrcode; + +/// +unittest { + import arsd.qrcode; + + void main() { + import arsd.simpledisplay; + + QrCode code = QrCode("http://arsdnet.net/"); + + enum drawsize = 4; + // you have to have some border around it + auto window = new SimpleWindow(code.size * drawsize + 80, code.size * drawsize + 80); + + { + auto painter = window.draw; + painter.clear(Color.white); + + foreach(y; 0 .. code.size) + foreach(x; 0 .. code.size) { + if(code[x, y]) { + painter.outlineColor = Color.black; + painter.fillColor = Color.black; + } else { + painter.outlineColor = Color.white; + painter.fillColor = Color.white; + } + painter.drawRectangle(Point(x * drawsize + 40, y * drawsize + 40), Size(drawsize, drawsize)); + } + } + + window.eventLoop(0); + } + + main; // exclude from docs +} + +import core.stdc.stddef; +import core.stdc.stdint; +import core.stdc.string; +import core.stdc.config; +import core.stdc.stdlib; +import core.stdc.math; + +/* + * 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. + */ + +alias qrcodegen_Ecc = int; + +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. + */ +alias qrcodegen_Mask = int; +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. + */ +alias qrcodegen_Mode = int; +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. + 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 ----*/ + +enum qrcodegen_VERSION_MIN = 1; // The minimum version number supported in the QR Code Model 2 standard +enum 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. +auto qrcodegen_BUFFER_LEN_FOR_VERSION(int n) { return ((((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. +auto qrcodegen_BUFFER_LEN_MAX() { return 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, + qrcodegen_Ecc ecl, int minVersion, int maxVersion, 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, + qrcodegen_Ecc ecl, int minVersion, int maxVersion, qrcodegen_Mask mask, bool boostEcl); + + + +/*---- Functions to extract raw data from QR Codes ----*/ + + +/* + * 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. + */ + +/*---- Forward declarations for private functions ----*/ + +// Regarding all public and private functions defined in this source file: +// - They require all pointer/array arguments to be not null unless the array length is zero. +// - They only read input scalar/array arguments, write to output pointer/array +// arguments, and return scalar values; they are "pure" functions. +// - They don't read mutable global variables or write to any global variables. +// - They don't perform I/O, read the clock, print to console, etc. +// - They allocate a small and constant amount of stack memory. +// - They don't allocate or free any memory on the heap. +// - They don't recurse or mutually recurse. All the code +// could be inlined into the top-level public functions. +// - They run in at most quadratic time with respect to input arguments. +// Most functions run in linear time, and some in constant time. +// There are no unbounded loops or non-obvious termination conditions. +// - They are completely thread-safe if the caller does not give the +// same writable buffer to concurrent calls to these functions. + +/*---- Private tables of constants ----*/ + +// The set of all legal characters in alphanumeric mode, where each character +// value maps to the index in the string. For checking text and encoding segments. +static const char *ALPHANUMERIC_CHARSET = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ $%*+-./:"; + +// For generating error correction codes. +private const int8_t[41][4] ECC_CODEWORDS_PER_BLOCK = [ + // Version: (note that index 0 is for padding, and is set to an illegal value) + //0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40 Error correction level + [-1, 7, 10, 15, 20, 26, 18, 20, 24, 30, 18, 20, 24, 26, 30, 22, 24, 28, 30, 28, 28, 28, 28, 30, 30, 26, 28, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30], // Low + [-1, 10, 16, 26, 18, 24, 16, 18, 22, 22, 26, 30, 22, 22, 24, 24, 28, 28, 26, 26, 26, 26, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28], // Medium + [-1, 13, 22, 18, 26, 18, 24, 18, 22, 20, 24, 28, 26, 24, 20, 30, 24, 28, 28, 26, 30, 28, 30, 30, 30, 30, 28, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30], // Quartile + [-1, 17, 28, 22, 16, 22, 28, 26, 26, 24, 28, 24, 28, 22, 24, 24, 30, 28, 28, 26, 28, 30, 24, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30], // High +]; + +enum qrcodegen_REED_SOLOMON_DEGREE_MAX = 30; // Based on the table above + +// For generating error correction codes. +private const int8_t[41][4] NUM_ERROR_CORRECTION_BLOCKS = [ + // Version: (note that index 0 is for padding, and is set to an illegal value) + //0, 1, 2, 3, 4, 5, 6, 7, 8, 9,10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40 Error correction level + [-1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 4, 4, 4, 4, 4, 6, 6, 6, 6, 7, 8, 8, 9, 9, 10, 12, 12, 12, 13, 14, 15, 16, 17, 18, 19, 19, 20, 21, 22, 24, 25], // Low + [-1, 1, 1, 1, 2, 2, 4, 4, 4, 5, 5, 5, 8, 9, 9, 10, 10, 11, 13, 14, 16, 17, 17, 18, 20, 21, 23, 25, 26, 28, 29, 31, 33, 35, 37, 38, 40, 43, 45, 47, 49], // Medium + [-1, 1, 1, 2, 2, 4, 4, 6, 6, 8, 8, 8, 10, 12, 16, 12, 17, 16, 18, 21, 20, 23, 23, 25, 27, 29, 34, 34, 35, 38, 40, 43, 45, 48, 51, 53, 56, 59, 62, 65, 68], // Quartile + [-1, 1, 1, 2, 4, 4, 4, 5, 6, 8, 8, 11, 11, 16, 16, 18, 16, 19, 21, 25, 25, 25, 34, 30, 32, 35, 37, 40, 42, 45, 48, 51, 54, 57, 60, 63, 66, 70, 74, 77, 81], // High +]; + +// For automatic mask pattern selection. +static const int PENALTY_N1 = 3; +static const int PENALTY_N2 = 3; +static const int PENALTY_N3 = 40; +static const int PENALTY_N4 = 10; + + + +/*---- High-level QR Code encoding functions ----*/ + +// Public function - see documentation comment in header file. +bool qrcodegen_encodeText(const char *text, uint8_t* tempBuffer, uint8_t* qrcode, + qrcodegen_Ecc ecl, int minVersion, int maxVersion, qrcodegen_Mask mask, bool boostEcl) { + + size_t textLen = strlen(text); + if (textLen == 0) + return qrcodegen_encodeSegmentsAdvanced(null, 0, ecl, minVersion, maxVersion, mask, boostEcl, tempBuffer, qrcode); + size_t bufLen = qrcodegen_BUFFER_LEN_FOR_VERSION(maxVersion); + + qrcodegen_Segment seg; + if (qrcodegen_isNumeric(text)) { + if (qrcodegen_calcSegmentBufferSize(qrcodegen_Mode_NUMERIC, textLen) > bufLen) + goto fail; + seg = qrcodegen_makeNumeric(text, tempBuffer); + } else if (qrcodegen_isAlphanumeric(text)) { + if (qrcodegen_calcSegmentBufferSize(qrcodegen_Mode_ALPHANUMERIC, textLen) > bufLen) + goto fail; + seg = qrcodegen_makeAlphanumeric(text, tempBuffer); + } else { + if (textLen > bufLen) + goto fail; + for (size_t i = 0; i < textLen; i++) + tempBuffer[i] = cast(uint8_t)text[i]; + seg.mode = qrcodegen_Mode_BYTE; + seg.bitLength = calcSegmentBitLength(seg.mode, textLen); + if (seg.bitLength == -1) + goto fail; + seg.numChars = cast(int)textLen; + seg.data = tempBuffer; + } + return qrcodegen_encodeSegmentsAdvanced(&seg, 1, ecl, minVersion, maxVersion, mask, boostEcl, tempBuffer, qrcode); + +fail: + qrcode[0] = 0; // Set size to invalid value for safety + return false; +} + + +// Public function - see documentation comment in header file. +bool qrcodegen_encodeBinary(uint8_t* dataAndTemp, size_t dataLen, uint8_t* qrcode, + qrcodegen_Ecc ecl, int minVersion, int maxVersion, qrcodegen_Mask mask, bool boostEcl) { + + qrcodegen_Segment seg; + seg.mode = qrcodegen_Mode_BYTE; + seg.bitLength = calcSegmentBitLength(seg.mode, dataLen); + if (seg.bitLength == -1) { + qrcode[0] = 0; // Set size to invalid value for safety + return false; + } + seg.numChars = cast(int)dataLen; + seg.data = dataAndTemp; + return qrcodegen_encodeSegmentsAdvanced(&seg, 1, ecl, minVersion, maxVersion, mask, boostEcl, dataAndTemp, qrcode); +} + + +// Appends the given number of low-order bits of the given value to the given byte-based +// bit buffer, increasing the bit length. Requires 0 <= numBits <= 16 and val < 2^numBits. +private void appendBitsToBuffer(uint val, int numBits, uint8_t* buffer, int *bitLen) { + assert(0 <= numBits && numBits <= 16 && cast(c_ulong)val >> numBits == 0); + for (int i = numBits - 1; i >= 0; i--, (*bitLen)++) + buffer[*bitLen >> 3] |= ((val >> i) & 1) << (7 - (*bitLen & 7)); +} + + + +/*---- Low-level QR Code encoding functions ----*/ + +// Public function - see documentation comment in header file. + +/* + * 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 qrcodegen_Segment* segs, size_t len, + qrcodegen_Ecc ecl, uint8_t* tempBuffer, uint8_t* qrcode) { + return qrcodegen_encodeSegmentsAdvanced(segs, len, ecl, + qrcodegen_VERSION_MIN, qrcodegen_VERSION_MAX, qrcodegen_Mask_AUTO, true, tempBuffer, qrcode); +} + + +// Public function - see documentation comment in header file. + + +/* + * 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 qrcodegen_Segment* segs, size_t len, qrcodegen_Ecc ecl, + int minVersion, int maxVersion, qrcodegen_Mask mask, bool boostEcl, uint8_t* tempBuffer, uint8_t* qrcode) { + assert(segs != null || len == 0); + assert(qrcodegen_VERSION_MIN <= minVersion && minVersion <= maxVersion && maxVersion <= qrcodegen_VERSION_MAX); + assert(0 <= cast(int)ecl && cast(int)ecl <= 3 && -1 <= cast(int)mask && cast(int)mask <= 7); + + // Find the minimal version_ number to use + int version_, dataUsedBits; + for (version_ = minVersion; ; version_++) { + int dataCapacityBits = getNumDataCodewords(version_, ecl) * 8; // Number of data bits available + dataUsedBits = getTotalBits(segs, len, version_); + if (dataUsedBits != -1 && dataUsedBits <= dataCapacityBits) + break; // This version_ number is found to be suitable + if (version_ >= maxVersion) { // All version_s in the range could not fit the given data + qrcode[0] = 0; // Set size to invalid value for safety + return false; + } + } + assert(dataUsedBits != -1); + + // Increase the error correction level while the data still fits in the current version_ number + for (int i = cast(int)qrcodegen_Ecc_MEDIUM; i <= cast(int)qrcodegen_Ecc_HIGH; i++) { // From low to high + if (boostEcl && dataUsedBits <= getNumDataCodewords(version_, cast(qrcodegen_Ecc)i) * 8) + ecl = cast(qrcodegen_Ecc)i; + } + + // Concatenate all segments to create the data bit string + memset(qrcode, 0, cast(size_t)qrcodegen_BUFFER_LEN_FOR_VERSION(version_) * (qrcode[0]).sizeof); + int bitLen = 0; + for (size_t i = 0; i < len; i++) { + const qrcodegen_Segment *seg = &segs[i]; + appendBitsToBuffer(cast(uint)seg.mode, 4, qrcode, &bitLen); + appendBitsToBuffer(cast(uint)seg.numChars, numCharCountBits(seg.mode, version_), qrcode, &bitLen); + for (int j = 0; j < seg.bitLength; j++) { + int bit = (seg.data[j >> 3] >> (7 - (j & 7))) & 1; + appendBitsToBuffer(cast(uint)bit, 1, qrcode, &bitLen); + } + } + assert(bitLen == dataUsedBits); + + // Add terminator and pad up to a byte if applicable + int dataCapacityBits = getNumDataCodewords(version_, ecl) * 8; + assert(bitLen <= dataCapacityBits); + int terminatorBits = dataCapacityBits - bitLen; + if (terminatorBits > 4) + terminatorBits = 4; + appendBitsToBuffer(0, terminatorBits, qrcode, &bitLen); + appendBitsToBuffer(0, (8 - bitLen % 8) % 8, qrcode, &bitLen); + assert(bitLen % 8 == 0); + + // Pad with alternating bytes until data capacity is reached + for (uint8_t padByte = 0xEC; bitLen < dataCapacityBits; padByte ^= 0xEC ^ 0x11) + appendBitsToBuffer(padByte, 8, qrcode, &bitLen); + + // Draw function and data codeword modules + addEccAndInterleave(qrcode, version_, ecl, tempBuffer); + initializeFunctionModules(version_, qrcode); + drawCodewords(tempBuffer, getNumRawDataModules(version_) / 8, qrcode); + drawWhiteFunctionModules(qrcode, version_); + initializeFunctionModules(version_, tempBuffer); + + // Handle masking + if (mask == qrcodegen_Mask_AUTO) { // Automatically choose best mask + long minPenalty = long.max; + for (int i = 0; i < 8; i++) { + qrcodegen_Mask msk = cast(qrcodegen_Mask)i; + applyMask(tempBuffer, qrcode, msk); + drawFormatBits(ecl, msk, qrcode); + long penalty = getPenaltyScore(qrcode); + if (penalty < minPenalty) { + mask = msk; + minPenalty = penalty; + } + applyMask(tempBuffer, qrcode, msk); // Undoes the mask due to XOR + } + } + assert(0 <= cast(int)mask && cast(int)mask <= 7); + applyMask(tempBuffer, qrcode, mask); + drawFormatBits(ecl, mask, qrcode); + return true; +} + + + +/*---- Error correction code generation functions ----*/ + +// Appends error correction bytes to each block of the given data array, then interleaves +// bytes from the blocks and stores them in the result array. data[0 : dataLen] contains +// the input data. data[dataLen : rawCodewords] is used as a temporary work area and will +// be clobbered by this function. The final answer is stored in result[0 : rawCodewords]. +private void addEccAndInterleave(uint8_t* data, int version_, qrcodegen_Ecc ecl, uint8_t* result) { + // Calculate parameter numbers + assert(0 <= cast(int)ecl && cast(int)ecl < 4 && qrcodegen_VERSION_MIN <= version_ && version_ <= qrcodegen_VERSION_MAX); + int numBlocks = NUM_ERROR_CORRECTION_BLOCKS[cast(int)ecl][version_]; + int blockEccLen = ECC_CODEWORDS_PER_BLOCK [cast(int)ecl][version_]; + int rawCodewords = getNumRawDataModules(version_) / 8; + int dataLen = getNumDataCodewords(version_, ecl); + int numShortBlocks = numBlocks - rawCodewords % numBlocks; + int shortBlockDataLen = rawCodewords / numBlocks - blockEccLen; + + // Split data into blocks, calculate ECC, and interleave + // (not concatenate) the bytes into a single sequence + uint8_t[qrcodegen_REED_SOLOMON_DEGREE_MAX] rsdiv; + reedSolomonComputeDivisor(blockEccLen, rsdiv.ptr); + const(uint8_t)* dat = data; + for (int i = 0; i < numBlocks; i++) { + int datLen = shortBlockDataLen + (i < numShortBlocks ? 0 : 1); + uint8_t *ecc = &data[dataLen]; // Temporary storage + reedSolomonComputeRemainder(dat, datLen, rsdiv.ptr, blockEccLen, ecc); + for (int j = 0, k = i; j < datLen; j++, k += numBlocks) { // Copy data + if (j == shortBlockDataLen) + k -= numShortBlocks; + result[k] = dat[j]; + } + for (int j = 0, k = dataLen + i; j < blockEccLen; j++, k += numBlocks) // Copy ECC + result[k] = ecc[j]; + dat += datLen; + } +} + + +// Returns the number of 8-bit codewords that can be used for storing data (not ECC), +// for the given version_ number and error correction level. The result is in the range [9, 2956]. +private int getNumDataCodewords(int version_, qrcodegen_Ecc ecl) { + int v = version_, e = cast(int)ecl; + assert(0 <= e && e < 4); + return getNumRawDataModules(v) / 8 + - ECC_CODEWORDS_PER_BLOCK [e][v] + * NUM_ERROR_CORRECTION_BLOCKS[e][v]; +} + + +// 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 int getNumRawDataModules(int ver) { + assert(qrcodegen_VERSION_MIN <= ver && ver <= qrcodegen_VERSION_MAX); + int result = (16 * ver + 128) * ver + 64; + if (ver >= 2) { + int numAlign = ver / 7 + 2; + result -= (25 * numAlign - 10) * numAlign - 55; + if (ver >= 7) + result -= 36; + } + assert(208 <= result && result <= 29648); + return result; +} + + + +/*---- Reed-Solomon ECC generator functions ----*/ + +// Computes a Reed-Solomon ECC generator polynomial for the given degree, storing in result[0 : degree]. +// This could be implemented as a lookup table over all possible parameter values, instead of as an algorithm. +private void reedSolomonComputeDivisor(int degree, uint8_t* result) { + assert(1 <= degree && degree <= qrcodegen_REED_SOLOMON_DEGREE_MAX); + // Polynomial coefficients are stored from highest to lowest power, excluding the leading term which is always 1. + // For example the polynomial x^3 + 255x^2 + 8x + 93 is stored as the uint8 array {255, 8, 93}. + memset(result, 0, cast(size_t)degree * (result[0]).sizeof); + result[degree - 1] = 1; // Start off with the monomial x^0 + + // Compute the product polynomial (x - r^0) * (x - r^1) * (x - r^2) * ... * (x - r^{degree-1}), + // drop the highest monomial term which is always 1x^degree. + // Note that r = 0x02, which is a generator element of this field GF(2^8/0x11D). + uint8_t root = 1; + for (int i = 0; i < degree; i++) { + // Multiply the current product by (x - r^i) + for (int j = 0; j < degree; j++) { + result[j] = reedSolomonMultiply(result[j], root); + if (j + 1 < degree) + result[j] ^= result[j + 1]; + } + root = reedSolomonMultiply(root, 0x02); + } +} + + +// Computes the Reed-Solomon error correction codeword for the given data and divisor polynomials. +// The remainder when data[0 : dataLen] is divided by divisor[0 : degree] is stored in result[0 : degree]. +// All polynomials are in big endian, and the generator has an implicit leading 1 term. +private void reedSolomonComputeRemainder(const uint8_t* data, int dataLen, + const uint8_t* generator, int degree, uint8_t* result) { + assert(1 <= degree && degree <= qrcodegen_REED_SOLOMON_DEGREE_MAX); + memset(result, 0, cast(size_t)degree * (result[0]).sizeof); + for (int i = 0; i < dataLen; i++) { // Polynomial division + uint8_t factor = data[i] ^ result[0]; + memmove(&result[0], &result[1], cast(size_t)(degree - 1) * (result[0]).sizeof); + result[degree - 1] = 0; + for (int j = 0; j < degree; j++) + result[j] ^= reedSolomonMultiply(generator[j], factor); + } +} + +// 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 uint8_t reedSolomonMultiply(uint8_t x, uint8_t y) { + // Russian peasant multiplication + uint8_t z = 0; + for (int i = 7; i >= 0; i--) { + z = cast(uint8_t)((z << 1) ^ ((z >> 7) * 0x11D)); + z ^= ((y >> i) & 1) * x; + } + return z; +} + + + +/*---- Drawing function modules ----*/ + +// Clears the given QR Code grid with white modules for the given +// version_'s size, then marks every function module as black. +private void initializeFunctionModules(int version_, uint8_t* qrcode) { + // Initialize QR Code + int qrsize = version_ * 4 + 17; + memset(qrcode, 0, cast(size_t)((qrsize * qrsize + 7) / 8 + 1) * (qrcode[0]).sizeof); + qrcode[0] = cast(uint8_t)qrsize; + + // Fill horizontal and vertical timing patterns + fillRectangle(6, 0, 1, qrsize, qrcode); + fillRectangle(0, 6, qrsize, 1, qrcode); + + // Fill 3 finder patterns (all corners except bottom right) and format bits + fillRectangle(0, 0, 9, 9, qrcode); + fillRectangle(qrsize - 8, 0, 8, 9, qrcode); + fillRectangle(0, qrsize - 8, 9, 8, qrcode); + + // Fill numerous alignment patterns + uint8_t[7] alignPatPos; + int numAlign = getAlignmentPatternPositions(version_, alignPatPos); + for (int i = 0; i < numAlign; i++) { + for (int j = 0; j < numAlign; j++) { + // Don't draw on the three finder corners + if (!((i == 0 && j == 0) || (i == 0 && j == numAlign - 1) || (i == numAlign - 1 && j == 0))) + fillRectangle(alignPatPos[i] - 2, alignPatPos[j] - 2, 5, 5, qrcode); + } + } + + // Fill version_ blocks + if (version_ >= 7) { + fillRectangle(qrsize - 11, 0, 3, 6, qrcode); + fillRectangle(0, qrsize - 11, 6, 3, qrcode); + } +} + + +// Draws white function modules and possibly some black modules onto the given QR Code, without changing +// non-function modules. This does not draw the format bits. This requires all function modules to be previously +// marked black (namely by initializeFunctionModules()), because this may skip redrawing black function modules. +static void drawWhiteFunctionModules(uint8_t* qrcode, int version_) { + // Draw horizontal and vertical timing patterns + int qrsize = qrcodegen_getSize(qrcode); + for (int i = 7; i < qrsize - 7; i += 2) { + setModule(qrcode, 6, i, false); + setModule(qrcode, i, 6, false); + } + + // Draw 3 finder patterns (all corners except bottom right; overwrites some timing modules) + for (int dy = -4; dy <= 4; dy++) { + for (int dx = -4; dx <= 4; dx++) { + int dist = abs(dx); + if (abs(dy) > dist) + dist = abs(dy); + if (dist == 2 || dist == 4) { + setModuleBounded(qrcode, 3 + dx, 3 + dy, false); + setModuleBounded(qrcode, qrsize - 4 + dx, 3 + dy, false); + setModuleBounded(qrcode, 3 + dx, qrsize - 4 + dy, false); + } + } + } + + // Draw numerous alignment patterns + uint8_t[7] alignPatPos; + int numAlign = getAlignmentPatternPositions(version_, alignPatPos); + for (int i = 0; i < numAlign; i++) { + for (int j = 0; j < numAlign; j++) { + if ((i == 0 && j == 0) || (i == 0 && j == numAlign - 1) || (i == numAlign - 1 && j == 0)) + continue; // Don't draw on the three finder corners + for (int dy = -1; dy <= 1; dy++) { + for (int dx = -1; dx <= 1; dx++) + setModule(qrcode, alignPatPos[i] + dx, alignPatPos[j] + dy, dx == 0 && dy == 0); + } + } + } + + // Draw version_ blocks + if (version_ >= 7) { + // Calculate error correction code and pack bits + int rem = version_; // version_ is uint6, in the range [7, 40] + for (int i = 0; i < 12; i++) + rem = (rem << 1) ^ ((rem >> 11) * 0x1F25); + c_long bits = cast(c_long)version_ << 12 | rem; // uint18 + assert(bits >> 18 == 0); + + // Draw two copies + for (int i = 0; i < 6; i++) { + for (int j = 0; j < 3; j++) { + int k = qrsize - 11 + j; + setModule(qrcode, k, i, (bits & 1) != 0); + setModule(qrcode, i, k, (bits & 1) != 0); + bits >>= 1; + } + } + } +} + + +// Draws two copies of the format bits (with its own error correction code) based +// on the given mask and error correction level. This always draws all modules of +// the format bits, unlike drawWhiteFunctionModules() which might skip black modules. +static void drawFormatBits(qrcodegen_Ecc ecl, qrcodegen_Mask mask, uint8_t* qrcode) { + // Calculate error correction code and pack bits + assert(0 <= cast(int)mask && cast(int)mask <= 7); + static const int[] table = [1, 0, 3, 2]; + int data = table[cast(int)ecl] << 3 | cast(int)mask; // errCorrLvl is uint2, mask is uint3 + int rem = data; + for (int i = 0; i < 10; i++) + rem = (rem << 1) ^ ((rem >> 9) * 0x537); + int bits = (data << 10 | rem) ^ 0x5412; // uint15 + assert(bits >> 15 == 0); + + // Draw first copy + for (int i = 0; i <= 5; i++) + setModule(qrcode, 8, i, getBit(bits, i)); + setModule(qrcode, 8, 7, getBit(bits, 6)); + setModule(qrcode, 8, 8, getBit(bits, 7)); + setModule(qrcode, 7, 8, getBit(bits, 8)); + for (int i = 9; i < 15; i++) + setModule(qrcode, 14 - i, 8, getBit(bits, i)); + + // Draw second copy + int qrsize = qrcodegen_getSize(qrcode); + for (int i = 0; i < 8; i++) + setModule(qrcode, qrsize - 1 - i, 8, getBit(bits, i)); + for (int i = 8; i < 15; i++) + setModule(qrcode, 8, qrsize - 15 + i, getBit(bits, i)); + setModule(qrcode, 8, qrsize - 8, true); // Always black +} + + +// Calculates and stores an ascending list of positions of alignment patterns +// for this version_ number, returning the length of the list (in the range [0,7]). +// 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 int getAlignmentPatternPositions(int version_, ref uint8_t[7] result) { + if (version_ == 1) + return 0; + int numAlign = version_ / 7 + 2; + int step = (version_ == 32) ? 26 : + (version_*4 + numAlign*2 + 1) / (numAlign*2 - 2) * 2; + for (int i = numAlign - 1, pos = version_ * 4 + 10; i >= 1; i--, pos -= step) + result[i] = cast(uint8_t)pos; + result[0] = 6; + return numAlign; +} + + +// Sets every pixel in the range [left : left + width] * [top : top + height] to black. +static void fillRectangle(int left, int top, int width, int height, uint8_t* qrcode) { + for (int dy = 0; dy < height; dy++) { + for (int dx = 0; dx < width; dx++) + setModule(qrcode, left + dx, top + dy, true); + } +} + + + +/*---- Drawing data modules and masking ----*/ + +// Draws the raw codewords (including data and ECC) onto the given QR Code. This requires the initial state of +// the QR Code to be black at function modules and white at codeword modules (including unused remainder bits). +static void drawCodewords(const uint8_t* data, int dataLen, uint8_t* qrcode) { + int qrsize = qrcodegen_getSize(qrcode); + int i = 0; // Bit index into the data + // Do the funny zigzag scan + for (int right = qrsize - 1; right >= 1; right -= 2) { // Index of right column in each column pair + if (right == 6) + right = 5; + for (int vert = 0; vert < qrsize; vert++) { // Vertical counter + for (int j = 0; j < 2; j++) { + int x = right - j; // Actual x coordinate + bool upward = ((right + 1) & 2) == 0; + int y = upward ? qrsize - 1 - vert : vert; // Actual y coordinate + if (!getModule(qrcode, x, y) && i < dataLen * 8) { + bool black = getBit(data[i >> 3], 7 - (i & 7)); + setModule(qrcode, x, y, black); + i++; + } + // If this QR Code has any remainder bits (0 to 7), they were assigned as + // 0/false/white by the constructor and are left unchanged by this method + } + } + } + assert(i == dataLen * 8); +} + + +// 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. +static void applyMask(const uint8_t* functionModules, uint8_t* qrcode, qrcodegen_Mask mask) { + assert(0 <= cast(int)mask && cast(int)mask <= 7); // Disallows qrcodegen_Mask_AUTO + int qrsize = qrcodegen_getSize(qrcode); + for (int y = 0; y < qrsize; y++) { + for (int x = 0; x < qrsize; x++) { + if (getModule(functionModules, x, y)) + continue; + bool invert; + switch (cast(int)mask) { + case 0: invert = (x + y) % 2 == 0; break; + case 1: invert = y % 2 == 0; break; + case 2: invert = x % 3 == 0; break; + case 3: invert = (x + y) % 3 == 0; break; + case 4: invert = (x / 3 + y / 2) % 2 == 0; break; + case 5: invert = x * y % 2 + x * y % 3 == 0; break; + case 6: invert = (x * y % 2 + x * y % 3) % 2 == 0; break; + case 7: invert = ((x + y) % 2 + x * y % 3) % 2 == 0; break; + default: assert(false); + } + bool val = getModule(qrcode, x, y); + setModule(qrcode, x, y, val ^ invert); + } + } +} + + +// Calculates and returns the penalty score based on state of the given QR Code's current modules. +// This is used by the automatic mask choice algorithm to find the mask pattern that yields the lowest score. +static long getPenaltyScore(const uint8_t* qrcode) { + int qrsize = qrcodegen_getSize(qrcode); + long result = 0; + + // Adjacent modules in row having same color, and finder-like patterns + for (int y = 0; y < qrsize; y++) { + bool runColor = false; + int runX = 0; + int[7] runHistory = 0; + for (int x = 0; x < qrsize; x++) { + if (getModule(qrcode, x, y) == runColor) { + runX++; + if (runX == 5) + result += PENALTY_N1; + else if (runX > 5) + result++; + } else { + finderPenaltyAddHistory(runX, runHistory, qrsize); + if (!runColor) + result += finderPenaltyCountPatterns(runHistory, qrsize) * PENALTY_N3; + runColor = getModule(qrcode, x, y); + runX = 1; + } + } + result += finderPenaltyTerminateAndCount(runColor, runX, runHistory, qrsize) * PENALTY_N3; + } + // Adjacent modules in column having same color, and finder-like patterns + for (int x = 0; x < qrsize; x++) { + bool runColor = false; + int runY = 0; + int[7] runHistory = 0; + for (int y = 0; y < qrsize; y++) { + if (getModule(qrcode, x, y) == runColor) { + runY++; + if (runY == 5) + result += PENALTY_N1; + else if (runY > 5) + result++; + } else { + finderPenaltyAddHistory(runY, runHistory, qrsize); + if (!runColor) + result += finderPenaltyCountPatterns(runHistory, qrsize) * PENALTY_N3; + runColor = getModule(qrcode, x, y); + runY = 1; + } + } + result += finderPenaltyTerminateAndCount(runColor, runY, runHistory, qrsize) * PENALTY_N3; + } + + // 2*2 blocks of modules having same color + for (int y = 0; y < qrsize - 1; y++) { + for (int x = 0; x < qrsize - 1; x++) { + bool color = getModule(qrcode, x, y); + if ( color == getModule(qrcode, x + 1, y) && + color == getModule(qrcode, x, y + 1) && + color == getModule(qrcode, x + 1, y + 1)) + result += PENALTY_N2; + } + } + + // Balance of black and white modules + int black = 0; + for (int y = 0; y < qrsize; y++) { + for (int x = 0; x < qrsize; x++) { + if (getModule(qrcode, x, y)) + black++; + } + } + int total = qrsize * qrsize; // Note that size is odd, so black/total != 1/2 + // Compute the smallest integer k >= 0 such that (45-5k)% <= black/total <= (55+5k)% + int k = cast(int)((labs(black * 20 - total * 10) + total - 1) / total) - 1; + result += k * PENALTY_N4; + return result; +} + + +// Can only be called immediately after a white run is added, and +// returns either 0, 1, or 2. A helper function for getPenaltyScore(). +static int finderPenaltyCountPatterns(const int[7] runHistory, int qrsize) { + int n = runHistory[1]; + assert(n <= qrsize * 3); + bool core = n > 0 && runHistory[2] == n && runHistory[3] == n * 3 && runHistory[4] == n && runHistory[5] == n; + // The maximum QR Code size is 177, hence the black run length n <= 177. + // Arithmetic is promoted to int, so n*4 will not overflow. + return (core && runHistory[0] >= n * 4 && runHistory[6] >= n ? 1 : 0) + + (core && runHistory[6] >= n * 4 && runHistory[0] >= n ? 1 : 0); +} + + +// Must be called at the end of a line (row or column) of modules. A helper function for getPenaltyScore(). +static int finderPenaltyTerminateAndCount(bool currentRunColor, int currentRunLength, ref int[7] runHistory, int qrsize) { + if (currentRunColor) { // Terminate black run + finderPenaltyAddHistory(currentRunLength, runHistory, qrsize); + currentRunLength = 0; + } + currentRunLength += qrsize; // Add white border to final run + finderPenaltyAddHistory(currentRunLength, runHistory, qrsize); + return finderPenaltyCountPatterns(runHistory, qrsize); +} + + +// Pushes the given value to the front and drops the last value. A helper function for getPenaltyScore(). +static void finderPenaltyAddHistory(int currentRunLength, ref int[7] runHistory, int qrsize) { + if (runHistory[0] == 0) + currentRunLength += qrsize; // Add white border to initial run + memmove(&runHistory[1], &runHistory[0], 6 * (runHistory[0]).sizeof); + runHistory[0] = currentRunLength; +} + + + +/*---- Basic QR Code information ----*/ + +// Public function - see documentation comment in header file. + +/* + * 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) { + assert(qrcode != null); + int result = qrcode[0]; + assert((qrcodegen_VERSION_MIN * 4 + 17) <= result + && result <= (qrcodegen_VERSION_MAX * 4 + 17)); + return result; +} + + +// Public function - see documentation comment in header file. + +/* + * 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) { + assert(qrcode != null); + int qrsize = qrcode[0]; + return (0 <= x && x < qrsize && 0 <= y && y < qrsize) && getModule(qrcode, x, y); +} + + +// Gets the module at the given coordinates, which must be in bounds. +private bool getModule(const uint8_t* qrcode, int x, int y) { + int qrsize = qrcode[0]; + assert(21 <= qrsize && qrsize <= 177 && 0 <= x && x < qrsize && 0 <= y && y < qrsize); + int index = y * qrsize + x; + return getBit(qrcode[(index >> 3) + 1], index & 7); +} + + +// Sets the module at the given coordinates, which must be in bounds. +private void setModule(uint8_t* qrcode, int x, int y, bool isBlack) { + int qrsize = qrcode[0]; + assert(21 <= qrsize && qrsize <= 177 && 0 <= x && x < qrsize && 0 <= y && y < qrsize); + int index = y * qrsize + x; + int bitIndex = index & 7; + int byteIndex = (index >> 3) + 1; + if (isBlack) + qrcode[byteIndex] |= 1 << bitIndex; + else + qrcode[byteIndex] &= (1 << bitIndex) ^ 0xFF; +} + + +// Sets the module at the given coordinates, doing nothing if out of bounds. +private void setModuleBounded(uint8_t* qrcode, int x, int y, bool isBlack) { + int qrsize = qrcode[0]; + if (0 <= x && x < qrsize && 0 <= y && y < qrsize) + setModule(qrcode, x, y, isBlack); +} + + +// Returns true iff the i'th bit of x is set to 1. Requires x >= 0 and 0 <= i <= 14. +static bool getBit(int x, int i) { + return ((x >> i) & 1) != 0; +} + + + +/*---- Segment handling ----*/ + +// Public function - see documentation comment in header file. + +/* + * 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) { + assert(text != null); + for (; *text != '\0'; text++) { + if (strchr(ALPHANUMERIC_CHARSET, *text) == null) + return false; + } + return true; +} + + +// Public function - see documentation comment in header file. + +/* + * 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) { + assert(text != null); + for (; *text != '\0'; text++) { + if (*text < '0' || *text > '9') + return false; + } + return true; +} + + +// Public function - see documentation comment in header file. + +/* + * 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(qrcodegen_Mode mode, size_t numChars) { + int temp = calcSegmentBitLength(mode, numChars); + if (temp == -1) + return SIZE_MAX; + assert(0 <= temp && temp <= INT16_MAX); + return (cast(size_t)temp + 7) / 8; +} + + +// Returns the number of data bits needed to represent a segment +// containing the given number of characters using the given mode. Notes: +// - Returns -1 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, INT16_MAX]. +// - 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 bits is returned. +// An actual ECI segment can have shorter data. For non-ECI modes, the result is exact. +private int calcSegmentBitLength(qrcodegen_Mode mode, size_t numChars) { + // All calculations are designed to avoid overflow on all platforms + if (numChars > cast(uint)INT16_MAX) + return -1; + c_long result = cast(c_long)numChars; + if (mode == qrcodegen_Mode_NUMERIC) + result = (result * 10 + 2) / 3; // ceil(10/3 * n) + else if (mode == qrcodegen_Mode_ALPHANUMERIC) + result = (result * 11 + 1) / 2; // ceil(11/2 * n) + else if (mode == qrcodegen_Mode_BYTE) + result *= 8; + else if (mode == qrcodegen_Mode_KANJI) + result *= 13; + else if (mode == qrcodegen_Mode_ECI && numChars == 0) + result = 3 * 8; + else { // Invalid argument + assert(false); + } + assert(result >= 0); + if (result > INT16_MAX) + return -1; + return cast(int)result; +} + + +// Public function - see documentation comment in header file. + +/* + * 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. + */ + +qrcodegen_Segment qrcodegen_makeBytes(const uint8_t* data, size_t len, uint8_t* buf) { + assert(data != null || len == 0); + qrcodegen_Segment result; + result.mode = qrcodegen_Mode_BYTE; + result.bitLength = calcSegmentBitLength(result.mode, len); + assert(result.bitLength != -1); + result.numChars = cast(int)len; + if (len > 0) + memcpy(buf, data, len * (buf[0]).sizeof); + result.data = buf; + return result; +} + + +// Public function - see documentation comment in header file. + +/* + * Returns a segment representing the given string of decimal digits encoded in numeric mode. + */ + +qrcodegen_Segment qrcodegen_makeNumeric(const(char)* digits, uint8_t* buf) { + assert(digits != null); + qrcodegen_Segment result; + size_t len = strlen(digits); + result.mode = qrcodegen_Mode_NUMERIC; + int bitLen = calcSegmentBitLength(result.mode, len); + assert(bitLen != -1); + result.numChars = cast(int)len; + if (bitLen > 0) + memset(buf, 0, (cast(size_t)bitLen + 7) / 8 * (buf[0]).sizeof); + result.bitLength = 0; + + uint accumData = 0; + int accumCount = 0; + for (; *digits != '\0'; digits++) { + char c = *digits; + assert('0' <= c && c <= '9'); + accumData = accumData * 10 + cast(uint)(c - '0'); + accumCount++; + if (accumCount == 3) { + appendBitsToBuffer(accumData, 10, buf, &result.bitLength); + accumData = 0; + accumCount = 0; + } + } + if (accumCount > 0) // 1 or 2 digits remaining + appendBitsToBuffer(accumData, accumCount * 3 + 1, buf, &result.bitLength); + assert(result.bitLength == bitLen); + result.data = buf; + return result; +} + + +// Public function - see documentation comment in header file. + +/* + * 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. + */ + +qrcodegen_Segment qrcodegen_makeAlphanumeric(const(char)* text, uint8_t* buf) { + assert(text != null); + qrcodegen_Segment result; + size_t len = strlen(text); + result.mode = qrcodegen_Mode_ALPHANUMERIC; + int bitLen = calcSegmentBitLength(result.mode, len); + assert(bitLen != -1); + result.numChars = cast(int)len; + if (bitLen > 0) + memset(buf, 0, (cast(size_t)bitLen + 7) / 8 * (buf[0]).sizeof); + result.bitLength = 0; + + uint accumData = 0; + int accumCount = 0; + for (; *text != '\0'; text++) { + const char *temp = strchr(ALPHANUMERIC_CHARSET, *text); + assert(temp != null); + accumData = accumData * 45 + cast(uint)(temp - ALPHANUMERIC_CHARSET); + accumCount++; + if (accumCount == 2) { + appendBitsToBuffer(accumData, 11, buf, &result.bitLength); + accumData = 0; + accumCount = 0; + } + } + if (accumCount > 0) // 1 character remaining + appendBitsToBuffer(accumData, 6, buf, &result.bitLength); + assert(result.bitLength == bitLen); + result.data = buf; + return result; +} + + +// Public function - see documentation comment in header file. + +/* + * Returns a segment representing an Extended Channel Interpretation + * (ECI) designator with the given assignment value. + */ + +qrcodegen_Segment qrcodegen_makeEci(c_long assignVal, uint8_t* buf) { + qrcodegen_Segment result; + result.mode = qrcodegen_Mode_ECI; + result.numChars = 0; + result.bitLength = 0; + if (assignVal < 0) + assert(false); + else if (assignVal < (1 << 7)) { + memset(buf, 0, 1 * (buf[0]).sizeof); + appendBitsToBuffer(cast(uint)assignVal, 8, buf, &result.bitLength); + } else if (assignVal < (1 << 14)) { + memset(buf, 0, 2 * (buf[0]).sizeof); + appendBitsToBuffer(2, 2, buf, &result.bitLength); + appendBitsToBuffer(cast(uint)assignVal, 14, buf, &result.bitLength); + } else if (assignVal < 1000000L) { + memset(buf, 0, 3 * (buf[0]).sizeof); + appendBitsToBuffer(6, 3, buf, &result.bitLength); + appendBitsToBuffer(cast(uint)(assignVal >> 10), 11, buf, &result.bitLength); + appendBitsToBuffer(cast(uint)(assignVal & 0x3FF), 10, buf, &result.bitLength); + } else + assert(false); + result.data = buf; + return result; +} + + +// 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 INT16_MAX. +private int getTotalBits(const qrcodegen_Segment* segs, size_t len, int version_) { + assert(segs != null || len == 0); + long result = 0; + for (size_t i = 0; i < len; i++) { + int numChars = segs[i].numChars; + int bitLength = segs[i].bitLength; + assert(0 <= numChars && numChars <= INT16_MAX); + assert(0 <= bitLength && bitLength <= INT16_MAX); + int ccbits = numCharCountBits(segs[i].mode, version_); + assert(0 <= ccbits && ccbits <= 16); + if (numChars >= (1L << ccbits)) + return -1; // The segment's length doesn't fit the field's bit width + result += 4L + ccbits + bitLength; + if (result > INT16_MAX) + return -1; // The sum might overflow an int type + } + assert(0 <= result && result <= INT16_MAX); + return cast(int)result; +} + + +// Returns the bit width of the character count field for a segment in the given mode +// in a QR Code at the given version_ number. The result is in the range [0, 16]. +static int numCharCountBits(qrcodegen_Mode mode, int version_) { + assert(qrcodegen_VERSION_MIN <= version_ && version_ <= qrcodegen_VERSION_MAX); + int i = (version_ + 7) / 17; + switch (mode) { + case qrcodegen_Mode_NUMERIC : { static immutable int[] temp1 = [10, 12, 14]; return temp1[i]; } + case qrcodegen_Mode_ALPHANUMERIC: { static immutable int[] temp2 = [ 9, 11, 13]; return temp2[i]; } + case qrcodegen_Mode_BYTE : { static immutable int[] temp3 = [ 8, 16, 16]; return temp3[i]; } + case qrcodegen_Mode_KANJI : { static immutable int[] temp4 = [ 8, 10, 12]; return temp4[i]; } + case qrcodegen_Mode_ECI : return 0; + default: assert(false); // Dummy value + } +} + +/++ + ++/ +struct QrCode { + ubyte[qrcodegen_BUFFER_LEN_MAX] qrcode; + + this(string text) { + ubyte[qrcodegen_BUFFER_LEN_MAX] tempBuffer; + bool ok = qrcodegen_encodeText((text ~ "\0").ptr, tempBuffer.ptr, qrcode.ptr, + qrcodegen_Ecc_MEDIUM, qrcodegen_VERSION_MIN, qrcodegen_VERSION_MAX, qrcodegen_Mask_AUTO, true); + if(!ok) + throw new Exception("qr code generation failed"); + } + + /++ + The size of the square of the code. It is size x size. + +/ + int size() { + return qrcodegen_getSize(qrcode.ptr); + } + + /++ + Returns true if it is a dark square, false if it is a light one. + +/ + bool opIndex(int x, int y) { + return qrcodegen_getModule(qrcode.ptr, x, y); + } +} +