/*
  * 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.
  */
 
 #include <assert.h>
 #include <limits.h>
 #include <stdlib.h>
 #include <string.h>
 #include "qrcodegen.h"
 
 #ifndef QRCODEGEN_TEST
 	#define testable static  // Keep functions private
 #else
 	#define testable  // Expose private functions
 #endif
 
 
 /*---- 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.
 
 testable void appendBitsToBuffer(unsigned int val, int numBits, uint8_t buffer[], int *bitLen);
 
 testable void addEccAndInterleave(uint8_t data[], int version, enum qrcodegen_Ecc ecl, uint8_t result[]);
 testable int getNumDataCodewords(int version, enum qrcodegen_Ecc ecl);
 testable int getNumRawDataModules(int ver);
 
 testable void calcReedSolomonGenerator(int degree, uint8_t result[]);
 testable void calcReedSolomonRemainder(const uint8_t data[], int dataLen,
 	const uint8_t generator[], int degree, uint8_t result[]);
 testable uint8_t finiteFieldMultiply(uint8_t x, uint8_t y);
 
 testable void initializeFunctionModules(int version, uint8_t qrcode[]);
 static void drawWhiteFunctionModules(uint8_t qrcode[], int version);
 static void drawFormatBits(enum qrcodegen_Ecc ecl, enum qrcodegen_Mask mask, uint8_t qrcode[]);
 testable int getAlignmentPatternPositions(int version, uint8_t result[7]);
 static void fillRectangle(int left, int top, int width, int height, uint8_t qrcode[]);
 
 static void drawCodewords(const uint8_t data[], int dataLen, uint8_t qrcode[]);
 static void applyMask(const uint8_t functionModules[], uint8_t qrcode[], enum qrcodegen_Mask mask);
 static long getPenaltyScore(const uint8_t qrcode[]);
 static void addRunToHistory(unsigned char run, unsigned char history[7]);
 static bool hasFinderLikePattern(const unsigned char runHistory[7]);
 
 testable bool getModule(const uint8_t qrcode[], int x, int y);
 testable void setModule(uint8_t qrcode[], int x, int y, bool isBlack);
 testable void setModuleBounded(uint8_t qrcode[], int x, int y, bool isBlack);
 static bool getBit(int x, int i);
 
 testable int calcSegmentBitLength(enum qrcodegen_Mode mode, size_t numChars);
 testable int getTotalBits(const struct qrcodegen_Segment segs[], size_t len, int version);
 static int numCharCountBits(enum qrcodegen_Mode mode, int version);
 
 
 
 /*---- 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.
 testable const int8_t ECC_CODEWORDS_PER_BLOCK[4][41] = {
 	// 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
 };
 
 #define qrcodegen_REED_SOLOMON_DEGREE_MAX 30  // Based on the table above
 
 // For generating error correction codes.
 testable const int8_t NUM_ERROR_CORRECTION_BLOCKS[4][41] = {
 	// 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[],
 		enum qrcodegen_Ecc ecl, int minVersion, int maxVersion, enum 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);
 	
 	struct 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] = (uint8_t)text[i];
 		seg.mode = qrcodegen_Mode_BYTE;
 		seg.bitLength = calcSegmentBitLength(seg.mode, textLen);
 		if (seg.bitLength == -1)
 			goto fail;
 		seg.numChars = (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[],
 		enum qrcodegen_Ecc ecl, int minVersion, int maxVersion, enum qrcodegen_Mask mask, bool boostEcl) {
 	
 	struct 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 = (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.
 testable void appendBitsToBuffer(unsigned int val, int numBits, uint8_t buffer[], int *bitLen) {
 	assert(0 <= numBits && numBits <= 16 && (unsigned long)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.
 bool qrcodegen_encodeSegments(const struct qrcodegen_Segment segs[], size_t len,
 		enum qrcodegen_Ecc ecl, uint8_t tempBuffer[], uint8_t qrcode[]) {
 	return qrcodegen_encodeSegmentsAdvanced(segs, len, ecl,
 		qrcodegen_VERSION_MIN, qrcodegen_VERSION_MAX, -1, true, tempBuffer, qrcode);
 }
 
 
 // Public function - see documentation comment in header file.
 bool qrcodegen_encodeSegmentsAdvanced(const struct qrcodegen_Segment segs[], size_t len, enum qrcodegen_Ecc ecl,
 		int minVersion, int maxVersion, int mask, bool boostEcl, uint8_t tempBuffer[], uint8_t qrcode[]) {
 	assert(segs != NULL || len == 0);
 	assert(qrcodegen_VERSION_MIN <= minVersion && minVersion <= maxVersion && maxVersion <= qrcodegen_VERSION_MAX);
 	assert(0 <= (int)ecl && (int)ecl <= 3 && -1 <= (int)mask && (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 versions 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 = (int)qrcodegen_Ecc_MEDIUM; i <= (int)qrcodegen_Ecc_HIGH; i++) {  // From low to high
 		if (boostEcl && dataUsedBits <= getNumDataCodewords(version, (enum qrcodegen_Ecc)i) * 8)
 			ecl = (enum qrcodegen_Ecc)i;
 	}
 	
 	// Concatenate all segments to create the data bit string
 	memset(qrcode, 0, qrcodegen_BUFFER_LEN_FOR_VERSION(version) * sizeof(qrcode[0]));
 	int bitLen = 0;
 	for (size_t i = 0; i < len; i++) {
 		const struct qrcodegen_Segment *seg = &segs[i];
 		appendBitsToBuffer((int)seg->mode, 4, qrcode, &bitLen);
 		appendBitsToBuffer(seg->numChars, numCharCountBits(seg->mode, version), qrcode, &bitLen);
 		for (int j = 0; j < seg->bitLength; j++)
 			appendBitsToBuffer((seg->data[j >> 3] >> (7 - (j & 7))) & 1, 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++) {
 			enum qrcodegen_Mask msk = (enum 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 <= (int)mask && (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].
 testable void addEccAndInterleave(uint8_t data[], int version, enum qrcodegen_Ecc ecl, uint8_t result[]) {
 	// Calculate parameter numbers
 	assert(0 <= (int)ecl && (int)ecl < 4 && qrcodegen_VERSION_MIN <= version && version <= qrcodegen_VERSION_MAX);
 	int numBlocks = NUM_ERROR_CORRECTION_BLOCKS[(int)ecl][version];
 	int blockEccLen = ECC_CODEWORDS_PER_BLOCK  [(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 generator[qrcodegen_REED_SOLOMON_DEGREE_MAX];
 	calcReedSolomonGenerator(blockEccLen, generator);
 	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
 		calcReedSolomonRemainder(dat, datLen, generator, 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].
 testable int getNumDataCodewords(int version, enum qrcodegen_Ecc ecl) {
 	int v = version, e = (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.
 testable 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;
 	}
 	return result;
 }
 
 
 
 /*---- Reed-Solomon ECC generator functions ----*/
 
 // Calculates the Reed-Solomon generator polynomial of the given degree, storing in result[0 : degree].
 testable void calcReedSolomonGenerator(int degree, uint8_t result[]) {
 	// Start with the monomial x^0
 	assert(1 <= degree && degree <= qrcodegen_REED_SOLOMON_DEGREE_MAX);
 	memset(result, 0, degree * sizeof(result[0]));
 	result[degree - 1] = 1;
 	
 	// Compute the product polynomial (x - r^0) * (x - r^1) * (x - r^2) * ... * (x - r^{degree-1}),
 	// drop the highest term, and store the rest of the coefficients in order of descending powers.
 	// 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] = finiteFieldMultiply(result[j], root);
 			if (j + 1 < degree)
 				result[j] ^= result[j + 1];
 		}
 		root = finiteFieldMultiply(root, 0x02);
 	}
 }
 
 
 // Calculates the remainder of the polynomial data[0 : dataLen] when divided by the generator[0 : degree], where all
 // polynomials are in big endian and the generator has an implicit leading 1 term, storing the result in result[0 : degree].
 testable void calcReedSolomonRemainder(const uint8_t data[], int dataLen,
 		const uint8_t generator[], int degree, uint8_t result[]) {
 	
 	// Perform polynomial division
 	assert(1 <= degree && degree <= qrcodegen_REED_SOLOMON_DEGREE_MAX);
 	memset(result, 0, degree * sizeof(result[0]));
 	for (int i = 0; i < dataLen; i++) {
 		uint8_t factor = data[i] ^ result[0];
 		memmove(&result[0], &result[1], (degree - 1) * sizeof(result[0]));
 		result[degree - 1] = 0;
 		for (int j = 0; j < degree; j++)
 			result[j] ^= finiteFieldMultiply(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 finiteFieldMultiply(uint8_t x, uint8_t y) {
 	// Russian peasant multiplication
 	uint8_t z = 0;
 	for (int i = 7; i >= 0; i--) {
 		z = (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, ((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] = 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++) {
 		unsigned char runHistory[7] = {0};
 		bool color = false;
 		unsigned char runX = 0;
 		for (int x = 0; x < qrsize; x++) {
 			if (getModule(qrcode, x, y) == color) {
 				runX++;
 				if (runX == 5)
 					result += PENALTY_N1;
 				else if (runX > 5)
 					result++;
 			} else {
 				addRunToHistory(runX, runHistory);
 				if (!color && hasFinderLikePattern(runHistory))
 					result += PENALTY_N3;
 				color = getModule(qrcode, x, y);
 				runX = 1;
 			}
 		}
 		addRunToHistory(runX, runHistory);
 		if (color)
 			addRunToHistory(0, runHistory);  // Dummy run of white
 		if (hasFinderLikePattern(runHistory))
 			result += PENALTY_N3;
 	}
 	// Adjacent modules in column having same color, and finder-like patterns
 	for (int x = 0; x < qrsize; x++) {
 		unsigned char runHistory[7] = {0};
 		bool color = false;
 		unsigned char runY = 0;
 		for (int y = 0; y < qrsize; y++) {
 			if (getModule(qrcode, x, y) == color) {
 				runY++;
 				if (runY == 5)
 					result += PENALTY_N1;
 				else if (runY > 5)
 					result++;
 			} else {
 				addRunToHistory(runY, runHistory);
 				if (!color && hasFinderLikePattern(runHistory))
 					result += PENALTY_N3;
 				color = getModule(qrcode, x, y);
 				runY = 1;
 			}
 		}
 		addRunToHistory(runY, runHistory);
 		if (color)
 			addRunToHistory(0, runHistory);  // Dummy run of white
 		if (hasFinderLikePattern(runHistory))
 			result += 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;
 }
 
 
 // Inserts the given value to the front of the given array, which shifts over the
 // existing values and deletes the last value. A helper function for getPenaltyScore().
 static void addRunToHistory(unsigned char run, unsigned char history[7]) {
 	memmove(&history[1], &history[0], 6 * sizeof(history[0]));
 	history[0] = run;
 }
 
 
 // Tests whether the given run history has the pattern of ratio 1:1:3:1:1 in the middle, and
 // surrounded by at least 4 on either or both ends. A helper function for getPenaltyScore().
 // Must only be called immediately after a run of white modules has ended.
 static bool hasFinderLikePattern(const unsigned char runHistory[7]) {
 	unsigned char n = runHistory[1];
 	// The maximum QR Code size is 177, hence the run length n <= 177.
 	// Arithmetic is promoted to int, so n*4 will not overflow.
 	return n > 0 && runHistory[2] == n && runHistory[4] == n && runHistory[5] == n
 		&& runHistory[3] == n * 3 && (runHistory[0] >= n * 4 || runHistory[6] >= n * 4);
 }
 
 
 
 /*---- 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 ((unsigned int)result > (unsigned int)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(assignVal, 8, buf, &result.bitLength);
 	} else if (assignVal < (1 << 14)) {
 		memset(buf, 0, 2 * sizeof(buf[0]));
 		appendBitsToBuffer(2, 2, buf, &result.bitLength);
 		appendBitsToBuffer(assignVal, 14, buf, &result.bitLength);
 	} else if (assignVal < 1000000L) {
 		memset(buf, 0, 3 * sizeof(buf[0]));
 		appendBitsToBuffer(6, 3, buf, &result.bitLength);
 		appendBitsToBuffer(assignVal >> 10, 11, buf, &result.bitLength);
 		appendBitsToBuffer(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
 	}
 }
 
 int qrcodegen_getMinFitVersion(enum qrcodegen_Ecc ecl, size_t dataLen)
 {
 	struct qrcodegen_Segment seg;
 	seg.mode = qrcodegen_Mode_BYTE;
 	seg.bitLength = calcSegmentBitLength(seg.mode, dataLen);
 	seg.numChars = (int)dataLen;
 
 	for (int version = qrcodegen_VERSION_MIN; version <= qrcodegen_VERSION_MAX; version++) {
 		int dataCapacityBits = getNumDataCodewords(version, ecl) * 8;  // Number of data bits available
 		int dataUsedBits = getTotalBits(&seg, 1, version);
 		if (dataUsedBits != -1 && dataUsedBits <= dataCapacityBits)
 			return version;
 	}
 	return -1;
 }
 
 int qrcodegen_version2size(int version)
 {
 	if (version < qrcodegen_VERSION_MIN || version > qrcodegen_VERSION_MAX) {
 		return -1;
 	}
 
 	return ((version - 1)*4 + 21);
 }

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