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1023 lines
40 KiB
C
1023 lines
40 KiB
C
/*
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* QR Code generator library (C)
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*
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* Copyright (c) Project Nayuki. (MIT License)
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* https://www.nayuki.io/page/qr-code-generator-library
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy of
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* this software and associated documentation files (the "Software"), to deal in
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* the Software without restriction, including without limitation the rights to
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* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
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* the Software, and to permit persons to whom the Software is furnished to do so,
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* subject to the following conditions:
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* - The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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* - The Software is provided "as is", without warranty of any kind, express or
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* implied, including but not limited to the warranties of merchantability,
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* fitness for a particular purpose and noninfringement. In no event shall the
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* authors or copyright holders be liable for any claim, damages or other
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* liability, whether in an action of contract, tort or otherwise, arising from,
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* out of or in connection with the Software or the use or other dealings in the
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* Software.
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*/
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#include <assert.h>
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#include <limits.h>
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#include <stdlib.h>
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#include <string.h>
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#include "qrcodegen.h"
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#ifndef QRCODEGEN_TEST
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#define testable static // Keep functions private
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#else
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#define testable // Expose private functions
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#endif
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/*---- Forward declarations for private functions ----*/
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// Regarding all public and private functions defined in this source file:
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// - They require all pointer/array arguments to be not null unless the array length is zero.
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// - They only read input scalar/array arguments, write to output pointer/array
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// arguments, and return scalar values; they are "pure" functions.
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// - They don't read mutable global variables or write to any global variables.
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// - They don't perform I/O, read the clock, print to console, etc.
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// - They allocate a small and constant amount of stack memory.
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// - They don't allocate or free any memory on the heap.
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// - They don't recurse or mutually recurse. All the code
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// could be inlined into the top-level public functions.
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// - They run in at most quadratic time with respect to input arguments.
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// Most functions run in linear time, and some in constant time.
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// There are no unbounded loops or non-obvious termination conditions.
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// - They are completely thread-safe if the caller does not give the
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// same writable buffer to concurrent calls to these functions.
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testable void appendBitsToBuffer(unsigned int val, int numBits, uint8_t buffer[], int *bitLen);
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testable void addEccAndInterleave(uint8_t data[], int version, enum qrcodegen_Ecc ecl, uint8_t result[]);
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testable int getNumDataCodewords(int version, enum qrcodegen_Ecc ecl);
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testable int getNumRawDataModules(int ver);
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testable void reedSolomonComputeDivisor(int degree, uint8_t result[]);
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testable void reedSolomonComputeRemainder(const uint8_t data[], int dataLen,
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const uint8_t generator[], int degree, uint8_t result[]);
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testable uint8_t reedSolomonMultiply(uint8_t x, uint8_t y);
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testable void initializeFunctionModules(int version, uint8_t qrcode[]);
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static void drawWhiteFunctionModules(uint8_t qrcode[], int version);
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static void drawFormatBits(enum qrcodegen_Ecc ecl, enum qrcodegen_Mask mask, uint8_t qrcode[]);
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testable int getAlignmentPatternPositions(int version, uint8_t result[7]);
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static void fillRectangle(int left, int top, int width, int height, uint8_t qrcode[]);
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static void drawCodewords(const uint8_t data[], int dataLen, uint8_t qrcode[]);
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static void applyMask(const uint8_t functionModules[], uint8_t qrcode[], enum qrcodegen_Mask mask);
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static long getPenaltyScore(const uint8_t qrcode[]);
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static int finderPenaltyCountPatterns(const int runHistory[7], int qrsize);
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static int finderPenaltyTerminateAndCount(bool currentRunColor, int currentRunLength, int runHistory[7], int qrsize);
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static void finderPenaltyAddHistory(int currentRunLength, int runHistory[7]);
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testable bool getModule(const uint8_t qrcode[], int x, int y);
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testable void setModule(uint8_t qrcode[], int x, int y, bool isBlack);
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testable void setModuleBounded(uint8_t qrcode[], int x, int y, bool isBlack);
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static bool getBit(int x, int i);
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testable int calcSegmentBitLength(enum qrcodegen_Mode mode, size_t numChars);
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testable int getTotalBits(const struct qrcodegen_Segment segs[], size_t len, int version);
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static int numCharCountBits(enum qrcodegen_Mode mode, int version);
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/*---- Private tables of constants ----*/
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// The set of all legal characters in alphanumeric mode, where each character
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// value maps to the index in the string. For checking text and encoding segments.
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static const char *ALPHANUMERIC_CHARSET = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ $%*+-./:";
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// For generating error correction codes.
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testable const int8_t ECC_CODEWORDS_PER_BLOCK[4][41] = {
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// Version: (note that index 0 is for padding, and is set to an illegal value)
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//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
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{-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
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{-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
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{-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
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{-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
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};
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#define qrcodegen_REED_SOLOMON_DEGREE_MAX 30 // Based on the table above
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// For generating error correction codes.
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testable const int8_t NUM_ERROR_CORRECTION_BLOCKS[4][41] = {
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// Version: (note that index 0 is for padding, and is set to an illegal value)
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//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
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{-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
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{-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
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{-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
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{-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
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};
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// For automatic mask pattern selection.
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static const int PENALTY_N1 = 3;
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static const int PENALTY_N2 = 3;
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static const int PENALTY_N3 = 40;
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static const int PENALTY_N4 = 10;
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/*---- High-level QR Code encoding functions ----*/
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// Public function - see documentation comment in header file.
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bool qrcodegen_encodeText(const char *text, uint8_t tempBuffer[], uint8_t qrcode[],
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enum qrcodegen_Ecc ecl, int minVersion, int maxVersion, enum qrcodegen_Mask mask, bool boostEcl) {
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size_t textLen = strlen(text);
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if (textLen == 0)
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return qrcodegen_encodeSegmentsAdvanced(NULL, 0, ecl, minVersion, maxVersion, mask, boostEcl, tempBuffer, qrcode);
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size_t bufLen = (size_t)qrcodegen_BUFFER_LEN_FOR_VERSION(maxVersion);
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struct qrcodegen_Segment seg;
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if (qrcodegen_isNumeric(text)) {
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if (qrcodegen_calcSegmentBufferSize(qrcodegen_Mode_NUMERIC, textLen) > bufLen)
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goto fail;
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seg = qrcodegen_makeNumeric(text, tempBuffer);
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} else if (qrcodegen_isAlphanumeric(text)) {
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if (qrcodegen_calcSegmentBufferSize(qrcodegen_Mode_ALPHANUMERIC, textLen) > bufLen)
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goto fail;
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seg = qrcodegen_makeAlphanumeric(text, tempBuffer);
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} else {
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if (textLen > bufLen)
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goto fail;
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for (size_t i = 0; i < textLen; i++)
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tempBuffer[i] = (uint8_t)text[i];
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seg.mode = qrcodegen_Mode_BYTE;
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seg.bitLength = calcSegmentBitLength(seg.mode, textLen);
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if (seg.bitLength == -1)
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goto fail;
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seg.numChars = (int)textLen;
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seg.data = tempBuffer;
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}
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return qrcodegen_encodeSegmentsAdvanced(&seg, 1, ecl, minVersion, maxVersion, mask, boostEcl, tempBuffer, qrcode);
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fail:
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qrcode[0] = 0; // Set size to invalid value for safety
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return false;
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}
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// Public function - see documentation comment in header file.
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bool qrcodegen_encodeBinary(uint8_t dataAndTemp[], size_t dataLen, uint8_t qrcode[],
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enum qrcodegen_Ecc ecl, int minVersion, int maxVersion, enum qrcodegen_Mask mask, bool boostEcl) {
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struct qrcodegen_Segment seg;
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seg.mode = qrcodegen_Mode_BYTE;
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seg.bitLength = calcSegmentBitLength(seg.mode, dataLen);
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if (seg.bitLength == -1) {
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qrcode[0] = 0; // Set size to invalid value for safety
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return false;
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}
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seg.numChars = (int)dataLen;
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seg.data = dataAndTemp;
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return qrcodegen_encodeSegmentsAdvanced(&seg, 1, ecl, minVersion, maxVersion, mask, boostEcl, dataAndTemp, qrcode);
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}
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// Appends the given number of low-order bits of the given value to the given byte-based
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// bit buffer, increasing the bit length. Requires 0 <= numBits <= 16 and val < 2^numBits.
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testable void appendBitsToBuffer(unsigned int val, int numBits, uint8_t buffer[], int *bitLen) {
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assert(0 <= numBits && numBits <= 16 && (unsigned long)val >> numBits == 0);
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for (int i = numBits - 1; i >= 0; i--, (*bitLen)++)
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buffer[*bitLen >> 3] |= ((val >> i) & 1) << (7 - (*bitLen & 7));
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}
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/*---- Low-level QR Code encoding functions ----*/
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// Public function - see documentation comment in header file.
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bool qrcodegen_encodeSegments(const struct qrcodegen_Segment segs[], size_t len,
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enum qrcodegen_Ecc ecl, uint8_t tempBuffer[], uint8_t qrcode[]) {
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return qrcodegen_encodeSegmentsAdvanced(segs, len, ecl,
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qrcodegen_VERSION_MIN, qrcodegen_VERSION_MAX, qrcodegen_Mask_AUTO, true, tempBuffer, qrcode);
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}
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// Public function - see documentation comment in header file.
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bool qrcodegen_encodeSegmentsAdvanced(const struct qrcodegen_Segment segs[], size_t len, enum qrcodegen_Ecc ecl,
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int minVersion, int maxVersion, enum qrcodegen_Mask mask, bool boostEcl, uint8_t tempBuffer[], uint8_t qrcode[]) {
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assert(segs != NULL || len == 0);
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assert(qrcodegen_VERSION_MIN <= minVersion && minVersion <= maxVersion && maxVersion <= qrcodegen_VERSION_MAX);
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assert(0 <= (int)ecl && (int)ecl <= 3 && -1 <= (int)mask && (int)mask <= 7);
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// Find the minimal version number to use
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int version, dataUsedBits;
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for (version = minVersion; ; version++) {
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int dataCapacityBits = getNumDataCodewords(version, ecl) * 8; // Number of data bits available
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dataUsedBits = getTotalBits(segs, len, version);
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if (dataUsedBits != -1 && dataUsedBits <= dataCapacityBits)
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break; // This version number is found to be suitable
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if (version >= maxVersion) { // All versions in the range could not fit the given data
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qrcode[0] = 0; // Set size to invalid value for safety
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return false;
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}
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}
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assert(dataUsedBits != -1);
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// Increase the error correction level while the data still fits in the current version number
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for (int i = (int)qrcodegen_Ecc_MEDIUM; i <= (int)qrcodegen_Ecc_HIGH; i++) { // From low to high
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if (boostEcl && dataUsedBits <= getNumDataCodewords(version, (enum qrcodegen_Ecc)i) * 8)
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ecl = (enum qrcodegen_Ecc)i;
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}
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// Concatenate all segments to create the data bit string
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memset(qrcode, 0, (size_t)qrcodegen_BUFFER_LEN_FOR_VERSION(version) * sizeof(qrcode[0]));
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int bitLen = 0;
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for (size_t i = 0; i < len; i++) {
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const struct qrcodegen_Segment *seg = &segs[i];
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appendBitsToBuffer((unsigned int)seg->mode, 4, qrcode, &bitLen);
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appendBitsToBuffer((unsigned int)seg->numChars, numCharCountBits(seg->mode, version), qrcode, &bitLen);
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for (int j = 0; j < seg->bitLength; j++) {
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int bit = (seg->data[j >> 3] >> (7 - (j & 7))) & 1;
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appendBitsToBuffer((unsigned int)bit, 1, qrcode, &bitLen);
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}
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}
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assert(bitLen == dataUsedBits);
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// Add terminator and pad up to a byte if applicable
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int dataCapacityBits = getNumDataCodewords(version, ecl) * 8;
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assert(bitLen <= dataCapacityBits);
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int terminatorBits = dataCapacityBits - bitLen;
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if (terminatorBits > 4)
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terminatorBits = 4;
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appendBitsToBuffer(0, terminatorBits, qrcode, &bitLen);
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appendBitsToBuffer(0, (8 - bitLen % 8) % 8, qrcode, &bitLen);
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assert(bitLen % 8 == 0);
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// Pad with alternating bytes until data capacity is reached
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for (uint8_t padByte = 0xEC; bitLen < dataCapacityBits; padByte ^= 0xEC ^ 0x11)
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appendBitsToBuffer(padByte, 8, qrcode, &bitLen);
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// Draw function and data codeword modules
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addEccAndInterleave(qrcode, version, ecl, tempBuffer);
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initializeFunctionModules(version, qrcode);
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drawCodewords(tempBuffer, getNumRawDataModules(version) / 8, qrcode);
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drawWhiteFunctionModules(qrcode, version);
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initializeFunctionModules(version, tempBuffer);
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// Handle masking
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if (mask == qrcodegen_Mask_AUTO) { // Automatically choose best mask
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long minPenalty = LONG_MAX;
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for (int i = 0; i < 8; i++) {
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enum qrcodegen_Mask msk = (enum qrcodegen_Mask)i;
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applyMask(tempBuffer, qrcode, msk);
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drawFormatBits(ecl, msk, qrcode);
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long penalty = getPenaltyScore(qrcode);
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if (penalty < minPenalty) {
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mask = msk;
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minPenalty = penalty;
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}
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applyMask(tempBuffer, qrcode, msk); // Undoes the mask due to XOR
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}
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}
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assert(0 <= (int)mask && (int)mask <= 7);
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applyMask(tempBuffer, qrcode, mask);
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drawFormatBits(ecl, mask, qrcode);
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return true;
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}
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/*---- Error correction code generation functions ----*/
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// Appends error correction bytes to each block of the given data array, then interleaves
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// bytes from the blocks and stores them in the result array. data[0 : dataLen] contains
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// the input data. data[dataLen : rawCodewords] is used as a temporary work area and will
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// be clobbered by this function. The final answer is stored in result[0 : rawCodewords].
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testable void addEccAndInterleave(uint8_t data[], int version, enum qrcodegen_Ecc ecl, uint8_t result[]) {
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// Calculate parameter numbers
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assert(0 <= (int)ecl && (int)ecl < 4 && qrcodegen_VERSION_MIN <= version && version <= qrcodegen_VERSION_MAX);
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int numBlocks = NUM_ERROR_CORRECTION_BLOCKS[(int)ecl][version];
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int blockEccLen = ECC_CODEWORDS_PER_BLOCK [(int)ecl][version];
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int rawCodewords = getNumRawDataModules(version) / 8;
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int dataLen = getNumDataCodewords(version, ecl);
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int numShortBlocks = numBlocks - rawCodewords % numBlocks;
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int shortBlockDataLen = rawCodewords / numBlocks - blockEccLen;
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// Split data into blocks, calculate ECC, and interleave
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// (not concatenate) the bytes into a single sequence
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uint8_t rsdiv[qrcodegen_REED_SOLOMON_DEGREE_MAX];
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reedSolomonComputeDivisor(blockEccLen, rsdiv);
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const uint8_t *dat = data;
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for (int i = 0; i < numBlocks; i++) {
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int datLen = shortBlockDataLen + (i < numShortBlocks ? 0 : 1);
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uint8_t *ecc = &data[dataLen]; // Temporary storage
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reedSolomonComputeRemainder(dat, datLen, rsdiv, blockEccLen, ecc);
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for (int j = 0, k = i; j < datLen; j++, k += numBlocks) { // Copy data
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if (j == shortBlockDataLen)
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k -= numShortBlocks;
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result[k] = dat[j];
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}
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for (int j = 0, k = dataLen + i; j < blockEccLen; j++, k += numBlocks) // Copy ECC
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result[k] = ecc[j];
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dat += datLen;
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}
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}
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// Returns the number of 8-bit codewords that can be used for storing data (not ECC),
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// for the given version number and error correction level. The result is in the range [9, 2956].
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testable int getNumDataCodewords(int version, enum qrcodegen_Ecc ecl) {
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int v = version, e = (int)ecl;
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assert(0 <= e && e < 4);
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return getNumRawDataModules(v) / 8
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- ECC_CODEWORDS_PER_BLOCK [e][v]
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* NUM_ERROR_CORRECTION_BLOCKS[e][v];
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}
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// Returns the number of data bits that can be stored in a QR Code of the given version number, after
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// all function modules are excluded. This includes remainder bits, so it might not be a multiple of 8.
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// The result is in the range [208, 29648]. This could be implemented as a 40-entry lookup table.
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testable int getNumRawDataModules(int ver) {
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assert(qrcodegen_VERSION_MIN <= ver && ver <= qrcodegen_VERSION_MAX);
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int result = (16 * ver + 128) * ver + 64;
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if (ver >= 2) {
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int numAlign = ver / 7 + 2;
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result -= (25 * numAlign - 10) * numAlign - 55;
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if (ver >= 7)
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result -= 36;
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}
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assert(208 <= result && result <= 29648);
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return result;
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}
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/*---- Reed-Solomon ECC generator functions ----*/
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// Computes a Reed-Solomon ECC generator polynomial for the given degree, storing in result[0 : degree].
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// This could be implemented as a lookup table over all possible parameter values, instead of as an algorithm.
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testable void reedSolomonComputeDivisor(int degree, uint8_t result[]) {
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assert(1 <= degree && degree <= qrcodegen_REED_SOLOMON_DEGREE_MAX);
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// Polynomial coefficients are stored from highest to lowest power, excluding the leading term which is always 1.
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// For example the polynomial x^3 + 255x^2 + 8x + 93 is stored as the uint8 array {255, 8, 93}.
|
|
memset(result, 0, (size_t)degree * sizeof(result[0]));
|
|
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.
|
|
testable 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, (size_t)degree * sizeof(result[0]));
|
|
for (int i = 0; i < dataLen; i++) { // Polynomial division
|
|
uint8_t factor = data[i] ^ result[0];
|
|
memmove(&result[0], &result[1], (size_t)(degree - 1) * sizeof(result[0]));
|
|
result[degree - 1] = 0;
|
|
for (int j = 0; j < degree; j++)
|
|
result[j] ^= reedSolomonMultiply(generator[j], factor);
|
|
}
|
|
}
|
|
|
|
#undef qrcodegen_REED_SOLOMON_DEGREE_MAX
|
|
|
|
|
|
// 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.
|
|
testable uint8_t reedSolomonMultiply(uint8_t x, uint8_t y) {
|
|
// Russian peasant multiplication
|
|
uint8_t z = 0;
|
|
for (int i = 7; i >= 0; i--) {
|
|
z = (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.
|
|
testable void initializeFunctionModules(int version, uint8_t qrcode[]) {
|
|
// Initialize QR Code
|
|
int qrsize = version * 4 + 17;
|
|
memset(qrcode, 0, (size_t)((qrsize * qrsize + 7) / 8 + 1) * sizeof(qrcode[0]));
|
|
qrcode[0] = (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 alignPatPos[7];
|
|
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 alignPatPos[7];
|
|
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);
|
|
long bits = (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(enum qrcodegen_Ecc ecl, enum qrcodegen_Mask mask, uint8_t qrcode[]) {
|
|
// Calculate error correction code and pack bits
|
|
assert(0 <= (int)mask && (int)mask <= 7);
|
|
static const int table[] = {1, 0, 3, 2};
|
|
int data = table[(int)ecl] << 3 | (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.
|
|
testable int getAlignmentPatternPositions(int version, uint8_t result[7]) {
|
|
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] = (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[], enum qrcodegen_Mask mask) {
|
|
assert(0 <= (int)mask && (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 ((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); return;
|
|
}
|
|
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 runHistory[7] = {0};
|
|
int padRun = qrsize; // Add white border to initial run
|
|
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 + padRun, runHistory);
|
|
padRun = 0;
|
|
if (!runColor)
|
|
result += finderPenaltyCountPatterns(runHistory, qrsize) * PENALTY_N3;
|
|
runColor = getModule(qrcode, x, y);
|
|
runX = 1;
|
|
}
|
|
}
|
|
result += finderPenaltyTerminateAndCount(runColor, runX + padRun, 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 runHistory[7] = {0};
|
|
int padRun = qrsize; // Add white border to initial run
|
|
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 + padRun, runHistory);
|
|
padRun = 0;
|
|
if (!runColor)
|
|
result += finderPenaltyCountPatterns(runHistory, qrsize) * PENALTY_N3;
|
|
runColor = getModule(qrcode, x, y);
|
|
runY = 1;
|
|
}
|
|
}
|
|
result += finderPenaltyTerminateAndCount(runColor, runY + padRun, 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 = (int)((labs(black * 20L - total * 10L) + 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 runHistory[7], 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, int runHistory[7], int qrsize) {
|
|
if (currentRunColor) { // Terminate black run
|
|
finderPenaltyAddHistory(currentRunLength, runHistory);
|
|
currentRunLength = 0;
|
|
}
|
|
currentRunLength += qrsize; // Add white border to final run
|
|
finderPenaltyAddHistory(currentRunLength, runHistory);
|
|
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, int runHistory[7]) {
|
|
memmove(&runHistory[1], &runHistory[0], 6 * sizeof(runHistory[0]));
|
|
runHistory[0] = currentRunLength;
|
|
}
|
|
|
|
|
|
|
|
/*---- Basic QR Code information ----*/
|
|
|
|
// Public function - see documentation comment in header file.
|
|
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.
|
|
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.
|
|
testable 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.
|
|
testable 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.
|
|
testable 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.
|
|
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.
|
|
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.
|
|
size_t qrcodegen_calcSegmentBufferSize(enum qrcodegen_Mode mode, size_t numChars) {
|
|
int temp = calcSegmentBitLength(mode, numChars);
|
|
if (temp == -1)
|
|
return SIZE_MAX;
|
|
assert(0 <= temp && temp <= INT16_MAX);
|
|
return ((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.
|
|
testable int calcSegmentBitLength(enum qrcodegen_Mode mode, size_t numChars) {
|
|
// All calculations are designed to avoid overflow on all platforms
|
|
if (numChars > (unsigned int)INT16_MAX)
|
|
return -1;
|
|
long result = (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);
|
|
return -1;
|
|
}
|
|
assert(result >= 0);
|
|
if (result > INT16_MAX)
|
|
return -1;
|
|
return (int)result;
|
|
}
|
|
|
|
|
|
// Public function - see documentation comment in header file.
|
|
struct qrcodegen_Segment qrcodegen_makeBytes(const uint8_t data[], size_t len, uint8_t buf[]) {
|
|
assert(data != NULL || len == 0);
|
|
struct qrcodegen_Segment result;
|
|
result.mode = qrcodegen_Mode_BYTE;
|
|
result.bitLength = calcSegmentBitLength(result.mode, len);
|
|
assert(result.bitLength != -1);
|
|
result.numChars = (int)len;
|
|
if (len > 0)
|
|
memcpy(buf, data, len * sizeof(buf[0]));
|
|
result.data = buf;
|
|
return result;
|
|
}
|
|
|
|
|
|
// Public function - see documentation comment in header file.
|
|
struct qrcodegen_Segment qrcodegen_makeNumeric(const char *digits, uint8_t buf[]) {
|
|
assert(digits != NULL);
|
|
struct qrcodegen_Segment result;
|
|
size_t len = strlen(digits);
|
|
result.mode = qrcodegen_Mode_NUMERIC;
|
|
int bitLen = calcSegmentBitLength(result.mode, len);
|
|
assert(bitLen != -1);
|
|
result.numChars = (int)len;
|
|
if (bitLen > 0)
|
|
memset(buf, 0, ((size_t)bitLen + 7) / 8 * sizeof(buf[0]));
|
|
result.bitLength = 0;
|
|
|
|
unsigned int accumData = 0;
|
|
int accumCount = 0;
|
|
for (; *digits != '\0'; digits++) {
|
|
char c = *digits;
|
|
assert('0' <= c && c <= '9');
|
|
accumData = accumData * 10 + (unsigned int)(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.
|
|
struct qrcodegen_Segment qrcodegen_makeAlphanumeric(const char *text, uint8_t buf[]) {
|
|
assert(text != NULL);
|
|
struct qrcodegen_Segment result;
|
|
size_t len = strlen(text);
|
|
result.mode = qrcodegen_Mode_ALPHANUMERIC;
|
|
int bitLen = calcSegmentBitLength(result.mode, len);
|
|
assert(bitLen != -1);
|
|
result.numChars = (int)len;
|
|
if (bitLen > 0)
|
|
memset(buf, 0, ((size_t)bitLen + 7) / 8 * sizeof(buf[0]));
|
|
result.bitLength = 0;
|
|
|
|
unsigned int accumData = 0;
|
|
int accumCount = 0;
|
|
for (; *text != '\0'; text++) {
|
|
const char *temp = strchr(ALPHANUMERIC_CHARSET, *text);
|
|
assert(temp != NULL);
|
|
accumData = accumData * 45 + (unsigned int)(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.
|
|
struct qrcodegen_Segment qrcodegen_makeEci(long assignVal, uint8_t buf[]) {
|
|
struct 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 * sizeof(buf[0]));
|
|
appendBitsToBuffer((unsigned int)assignVal, 8, buf, &result.bitLength);
|
|
} else if (assignVal < (1 << 14)) {
|
|
memset(buf, 0, 2 * sizeof(buf[0]));
|
|
appendBitsToBuffer(2, 2, buf, &result.bitLength);
|
|
appendBitsToBuffer((unsigned int)assignVal, 14, buf, &result.bitLength);
|
|
} else if (assignVal < 1000000L) {
|
|
memset(buf, 0, 3 * sizeof(buf[0]));
|
|
appendBitsToBuffer(6, 3, buf, &result.bitLength);
|
|
appendBitsToBuffer((unsigned int)(assignVal >> 10), 11, buf, &result.bitLength);
|
|
appendBitsToBuffer((unsigned int)(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.
|
|
testable int getTotalBits(const struct 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 (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(enum 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 const int temp[] = {10, 12, 14}; return temp[i]; }
|
|
case qrcodegen_Mode_ALPHANUMERIC: { static const int temp[] = { 9, 11, 13}; return temp[i]; }
|
|
case qrcodegen_Mode_BYTE : { static const int temp[] = { 8, 16, 16}; return temp[i]; }
|
|
case qrcodegen_Mode_KANJI : { static const int temp[] = { 8, 10, 12}; return temp[i]; }
|
|
case qrcodegen_Mode_ECI : return 0;
|
|
default: assert(false); return -1; // Dummy value
|
|
}
|
|
}
|