Function qrcode_initBytes

Libraries/QRCode/src/qrcode.c:770–844

@TODO: Return error if data is too big.

// @TODO: Return error if data is too big.
int8_t qrcode_initBytes(QRCode *qrcode, uint8_t *modules, uint8_t version, uint8_t ecc, uint8_t *data, uint16_t length) {
    uint8_t size = version * 4 + 17;
    qrcode->version = version;
    qrcode->size = size;
    qrcode->ecc = ecc;
    qrcode->modules = modules;
    
    uint8_t eccFormatBits = (ECC_FORMAT_BITS >> (2 * ecc)) & 0x03;
    
#if LOCK_VERSION == 0
    uint16_t moduleCount = NUM_RAW_DATA_MODULES[version - 1];
    uint16_t dataCapacity = moduleCount / 8 - NUM_ERROR_CORRECTION_CODEWORDS[eccFormatBits][version - 1];
#else
    version = LOCK_VERSION;
    uint16_t moduleCount = NUM_RAW_DATA_MODULES;
    uint16_t dataCapacity = moduleCount / 8 - NUM_ERROR_CORRECTION_CODEWORDS[eccFormatBits];
#endif

    struct BitBucket codewords;
    uint8_t codewordBytes[bb_getBufferSizeBytes(moduleCount)];
    bb_initBuffer(&codewords, codewordBytes, (int32_t)sizeof(codewordBytes));
    
    // Place the data code words into the buffer
    int8_t mode = encodeDataCodewords(&codewords, data, length, version);
    
    if (mode < 0) { return -1; }
    qrcode->mode = mode;
    
    // Add terminator and pad up to a byte if applicable
    uint32_t padding = (dataCapacity * 8) - codewords.bitOffsetOrWidth;
    if (padding > 4) { padding = 4; }
    bb_appendBits(&codewords, 0, padding);
    bb_appendBits(&codewords, 0, (8 - codewords.bitOffsetOrWidth % 8) % 8);

    // Pad with alternate bytes until data capacity is reached
    for (uint8_t padByte = 0xEC; codewords.bitOffsetOrWidth < (dataCapacity * 8); padByte ^= 0xEC ^ 0x11) {
        bb_appendBits(&codewords, padByte, 8);
    }

    BitBucket modulesGrid;
    bb_initGrid(&modulesGrid, modules, size);
    
    BitBucket isFunctionGrid;
    uint8_t isFunctionGridBytes[bb_getGridSizeBytes(size)];
    bb_initGrid(&isFunctionGrid, isFunctionGridBytes, size);
    
    // Draw function patterns, draw all codewords, do masking
    drawFunctionPatterns(&modulesGrid, &isFunctionGrid, version, eccFormatBits);
    performErrorCorrection(version, eccFormatBits, &codewords);
    drawCodewords(&modulesGrid, &isFunctionGrid, &codewords);
    
    // Find the best (lowest penalty) mask
    uint8_t mask = 0;
    int32_t minPenalty = INT32_MAX;
    for (uint8_t i = 0; i < 8; i++) {
        drawFormatBits(&modulesGrid, &isFunctionGrid, eccFormatBits, i);
        applyMask(&modulesGrid, &isFunctionGrid, i);
        int penalty = getPenaltyScore(&modulesGrid);