Prep DataSegment for multi mode QR codes #683

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Merged

Shane32 merged 7 commits into master from refactordataseg3

Oct 14, 2025

QRCoder/QRCodeGenerator/AlphanumericDataSegment.cs

            
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    @@ -27,10 +27,22 @@ public AlphanumericDataSegment(string alphanumericText)
  
            /// <param name="version">The QR code version (1-40, or -1 to -4 for Micro QR)</param>

            /// <returns>The total number of bits required for this segment</returns>

            public override int GetBitLength(int version)

            {

                return GetBitLength(Text.Length, version);

            }

            /// <summary>

            /// Calculates the total bit length for encoding alphanumeric text of a given length for a specific QR code version.

            /// Includes mode indicator, count indicator, and data bits.

            /// </summary>

            /// <param name="textLength">The length of the alphanumeric text</param>

            /// <param name="version">The QR code version (1-40, or -1 to -4 for Micro QR)</param>

            /// <returns>The total number of bits required</returns>

            public static int GetBitLength(int textLength, int version)

            {

                int modeIndicatorLength = 4;

                int countIndicatorLength = GetCountIndicatorLength(version, EncodingMode.Alphanumeric);

                int dataLength = AlphanumericEncoder.GetBitLength(Text);

                int dataLength = AlphanumericEncoder.GetBitLength(textLength);

                int length = modeIndicatorLength + countIndicatorLength + dataLength;

                return length;

    @@ -45,19 +57,33 @@ public override int GetBitLength(int version)
  
            /// <returns>The next index in the BitArray after the last bit written</returns>

            public override int WriteTo(BitArray bitArray, int startIndex, int version)

            {

                var index = startIndex;

                return WriteTo(Text, 0, Text.Length, bitArray, startIndex, version);

            }

            /// <summary>

            /// Writes a portion of alphanumeric text to a BitArray at the specified index.

            /// Includes mode indicator, count indicator, and data bits.

            /// </summary>

            /// <param name="text">The full alphanumeric text</param>

            /// <param name="offset">The starting index in the text to encode from</param>

            /// <param name="length">The number of characters to encode</param>

            /// <param name="bitArray">The target BitArray to write to</param>

            /// <param name="bitIndex">The starting index in the BitArray</param>

            /// <param name="version">The QR code version (1-40, or -1 to -4 for Micro QR)</param>

            /// <returns>The next index in the BitArray after the last bit written</returns>

            public static int WriteTo(string text, int offset, int length, BitArray bitArray, int bitIndex, int version)

            {

                // write mode indicator

                index = DecToBin((int)EncodingMode.Alphanumeric, 4, bitArray, index);

                bitIndex = DecToBin((int)EncodingMode.Alphanumeric, 4, bitArray, bitIndex);

                // write count indicator

                int countIndicatorLength = GetCountIndicatorLength(version, EncodingMode.Alphanumeric);

                index = DecToBin(Text.Length, countIndicatorLength, bitArray, index);

                bitIndex = DecToBin(length, countIndicatorLength, bitArray, bitIndex);

                // write data - encode alphanumeric text

                index = AlphanumericEncoder.WriteToBitArray(Text, bitArray, index);

                bitIndex = AlphanumericEncoder.WriteToBitArray(text, offset, length, bitArray, bitIndex);

                return index;

                return bitIndex;

            }

        }

    }

QRCoder/QRCodeGenerator/AlphanumericEncoder.cs

            
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    @@ -41,13 +41,13 @@ private static Dictionary<char, int> CreateAlphanumEncDict(char[] alphanumEncTab
  
            public static bool CanEncodeNonDigit(char c) => IsInRange(c, 'A', 'Z') || Array.IndexOf(_alphanumEncTable, c) >= 0;

            /// <summary>

            /// Calculates the bit length required to encode the given alphanumeric text.

            /// Calculates the bit length required to encode alphanumeric text of a given length.

            /// </summary>

            /// <param name="plainText">The alphanumeric text to be encoded.</param>

            /// <param name="textLength">The length of the alphanumeric text to be encoded.</param>

            /// <returns>The number of bits required to encode the text.</returns>

            public static int GetBitLength(string plainText)

            public static int GetBitLength(int textLength)

            {

                return (plainText.Length / 2) * 11 + (plainText.Length & 1) * 6;

                return (textLength / 2) * 11 + (textLength & 1) * 6;

            }

            /// <summary>

    @@ -59,25 +59,24 @@ public static int GetBitLength(string plainText)
  
            /// <returns>A BitArray representing the binary data of the encoded alphanumeric text.</returns>

            public static BitArray GetBitArray(string plainText)

            {

                var codeText = new BitArray(GetBitLength(plainText));

                WriteToBitArray(plainText, codeText, 0);

                var codeText = new BitArray(GetBitLength(plainText.Length));

                WriteToBitArray(plainText, 0, plainText.Length, codeText, 0);

                return codeText;

            }

            /// <summary>

            /// Writes alphanumeric plain text directly into an existing BitArray at the specified index.

            /// Writes a portion of alphanumeric plain text directly into an existing BitArray at the specified index.

            /// Alphanumeric encoding packs characters into 11-bit groups for each pair of characters,

            /// and 6 bits for a single remaining character if the total count is odd.

            /// </summary>

            /// <param name="plainText">The alphanumeric text to be encoded, which should only contain characters valid in QR alphanumeric mode.</param>

            /// <param name="index">The starting index in the text to encode from.</param>

            /// <param name="count">The number of characters to encode.</param>

            /// <param name="codeText">The target BitArray to write to.</param>

            /// <param name="codeIndex">The starting index in the BitArray where writing should begin.</param>

            /// <returns>The next index in the BitArray after the last bit written.</returns>

            public static int WriteToBitArray(string plainText, BitArray codeText, int codeIndex)

            public static int WriteToBitArray(string plainText, int index, int count, BitArray codeText, int codeIndex)

            {

                var index = 0;

                var count = plainText.Length;

                // Process each pair of characters.

                while (count >= 2)

                {

QRCoder/QRCodeGenerator/NumericDataSegment.cs

            
                      Original file line number
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                      Diff line change
                  
    @@ -27,10 +27,22 @@ public NumericDataSegment(string numericText)
  
            /// <param name="version">The QR code version (1-40, or -1 to -4 for Micro QR)</param>

            /// <returns>The total number of bits required for this segment</returns>

            public override int GetBitLength(int version)

            {

                return GetBitLength(Text.Length, version);

            }

            /// <summary>

            /// Calculates the total bit length for encoding numeric text of a given length for a specific QR code version.

            /// Includes mode indicator, count indicator, and data bits.

            /// </summary>

            /// <param name="textLength">The length of the numeric text</param>

            /// <param name="version">The QR code version (1-40, or -1 to -4 for Micro QR)</param>

            /// <returns>The total number of bits required</returns>

            public static int GetBitLength(int textLength, int version)

            {

                int modeIndicatorLength = 4;

                int countIndicatorLength = GetCountIndicatorLength(version, EncodingMode.Numeric);

                int dataLength = Text.Length / 3 * 10 + (Text.Length % 3 == 1 ? 4 : Text.Length % 3 == 2 ? 7 : 0);

                int dataLength = textLength / 3 * 10 + (textLength % 3 == 1 ? 4 : textLength % 3 == 2 ? 7 : 0);

                int length = modeIndicatorLength + countIndicatorLength + dataLength;

                return length;

    @@ -45,19 +57,33 @@ public override int GetBitLength(int version)
  
            /// <returns>The next index in the BitArray after the last bit written</returns>

            public override int WriteTo(BitArray bitArray, int startIndex, int version)

            {

                var index = startIndex;

                return WriteTo(Text, 0, Text.Length, bitArray, startIndex, version);

            }

            /// <summary>

            /// Writes a portion of numeric text to a BitArray at the specified index.

            /// Includes mode indicator, count indicator, and data bits.

            /// </summary>

            /// <param name="text">The full numeric text</param>

            /// <param name="startIndex">The starting index in the text to encode from</param>

            /// <param name="length">The number of characters to encode</param>

            /// <param name="bitArray">The target BitArray to write to</param>

            /// <param name="bitIndex">The starting index in the BitArray</param>

            /// <param name="version">The QR code version (1-40, or -1 to -4 for Micro QR)</param>

            /// <returns>The next index in the BitArray after the last bit written</returns>

            public static int WriteTo(string text, int startIndex, int length, BitArray bitArray, int bitIndex, int version)

            {

                var index = bitIndex;

                // write mode indicator

                index = DecToBin((int)EncodingMode.Numeric, 4, bitArray, index);

                // write count indicator

                int countIndicatorLength = GetCountIndicatorLength(version, EncodingMode.Numeric);

                index = DecToBin(Text.Length, countIndicatorLength, bitArray, index);

                index = DecToBin(length, countIndicatorLength, bitArray, index);

                // write data - encode numeric text

                var data = PlainTextToBinaryNumeric(Text);

                data.CopyTo(bitArray, 0, index, data.Length);

                index += data.Length;

                index = PlainTextToBinaryNumeric(text, startIndex, length, bitArray, index);

                return index;

            }

    @@ -74,10 +100,26 @@ private static BitArray PlainTextToBinaryNumeric(string plainText)
  
            // Calculate the length of the BitArray needed to encode the text.

            // Groups of three digits are encoded in 10 bits, remaining groups of two or one digits take 7 or 4 bits respectively.

            var bitArray = new BitArray(plainText.Length / 3 * 10 + (plainText.Length % 3 == 1 ? 4 : plainText.Length % 3 == 2 ? 7 : 0));

            var index = 0;

            PlainTextToBinaryNumeric(plainText, 0, plainText.Length, bitArray, 0);

            return bitArray;

        }

        /// <summary>

        /// Converts a portion of numeric plain text into a binary format specifically optimized for QR codes, writing directly to an existing BitArray.

        /// Numeric compression groups up to 3 digits into 10 bits, less for remaining digits if they do not complete a group of three.

        /// </summary>

        /// <param name="plainText">The numeric text to be encoded, which should only contain digit characters.</param>

        /// <param name="offset">The starting index in the text to encode from.</param>

        /// <param name="length">The number of characters to encode.</param>

        /// <param name="bitArray">The target BitArray to write to.</param>

        /// <param name="bitIndex">The starting index in the BitArray where bits will be written.</param>

        /// <returns>The next index in the BitArray after the last bit written.</returns>

        private static int PlainTextToBinaryNumeric(string plainText, int offset, int length, BitArray bitArray, int bitIndex)

        {

            var endIndex = offset + length;

            // Process each group of three digits.

            for (int i = 0; i < plainText.Length - 2; i += 3)

            for (int i = offset; i < endIndex - 2; i += 3)

            {

                // Parse the next three characters as a decimal integer.

    #if HAS_SPAN

    @@ -86,29 +128,22 @@ private static BitArray PlainTextToBinaryNumeric(string plainText)
  
                var dec = int.Parse(plainText.Substring(i, 3), NumberStyles.None, CultureInfo.InvariantCulture);

    #endif

                // Convert the decimal to binary and store it in the BitArray.

                index = DecToBin(dec, 10, bitArray, index);

                bitIndex = DecToBin(dec, 10, bitArray, bitIndex);

                offset += 3;

                length -= 3;

            }

            // Handle any remaining digits if the total number is not a multiple of three.

            if (plainText.Length % 3 == 2)  // Two remaining digits are encoded in 7 bits.

            if (length > 0)  // Two remaining digits are encoded in 7 bits; one remaining digit is encoded in 4 bits.

            {

    #if HAS_SPAN

                var dec = int.Parse(plainText.AsSpan(plainText.Length / 3 * 3, 2), NumberStyles.None, CultureInfo.InvariantCulture);

                var dec = int.Parse(plainText.AsSpan(offset, length), NumberStyles.None, CultureInfo.InvariantCulture);

    #else

                var dec = int.Parse(plainText.Substring(plainText.Length / 3 * 3, 2), NumberStyles.None, CultureInfo.InvariantCulture);

                var dec = int.Parse(plainText.Substring(offset, length), NumberStyles.None, CultureInfo.InvariantCulture);

    #endif

                index = DecToBin(dec, 7, bitArray, index);

            }

            else if (plainText.Length % 3 == 1)  // One remaining digit is encoded in 4 bits.

            {

    #if HAS_SPAN

                var dec = int.Parse(plainText.AsSpan(plainText.Length / 3 * 3, 1), NumberStyles.None, CultureInfo.InvariantCulture);

    #else

                var dec = int.Parse(plainText.Substring(plainText.Length / 3 * 3, 1), NumberStyles.None, CultureInfo.InvariantCulture);

    #endif

                index = DecToBin(dec, 4, bitArray, index);

                bitIndex = DecToBin(dec, length == 2 ? 7 : 4, bitArray, bitIndex);

            }

            return bitArray;

            return bitIndex;

        }

    }

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