Refactor BuildBitArrayFromSegment

QRCoder/QRCodeGenerator.cs

@@ -116,7 +116,7 @@ public static QRCodeData GenerateQrCode(string plainText, ECCLevel eccLevel, boo
         // Determine the appropriate version based on segment bit length
         int version = DetermineVersion(segment, eccLevel, requestedVersion);
         // Build the complete bit array for the determined version
-        var completeBitArray = BuildBitArrayFromSegment(segment, version);
+        var completeBitArray = segment.ToBitArray(version);
         return GenerateQrCode(completeBitArray, eccLevel, version);
     }
 
@@ -163,40 +163,6 @@ static int Throw(ECCLevel eccLevel, EncodingMode encoding, int version)
         }
     }
 
-    /// <summary>
-    /// Builds a complete BitArray from a data segment for a specific QR code version.
-    /// </summary>
-    private static BitArray BuildBitArrayFromSegment(DataSegment segment, int version)
-    {
-        // todo in subsequent PR: eliminate these local variables and directly access the struct
-        var eciMode = segment.EciMode;
-        var encoding = segment.EncodingMode;
-        int dataInputLength = segment.CharacterCount;
-        var codedText = segment.Data;
-        int completeBitArrayLength = segment.GetBitLength(version);
-        int countIndicatorLength = GetCountIndicatorLength(version, segment.EncodingMode);
-
-        var completeBitArray = new BitArray(completeBitArrayLength);
-
-        // write mode indicator
-        var completeBitArrayIndex = 0;
-        if (eciMode != EciMode.Default)
-        {
-            completeBitArrayIndex = DecToBin((int)EncodingMode.ECI, 4, completeBitArray, completeBitArrayIndex);
-            completeBitArrayIndex = DecToBin((int)eciMode, 8, completeBitArray, completeBitArrayIndex);
-        }
-        completeBitArrayIndex = DecToBin((int)encoding, 4, completeBitArray, completeBitArrayIndex);
-        // write count indicator
-        completeBitArrayIndex = DecToBin(dataInputLength, countIndicatorLength, completeBitArray, completeBitArrayIndex);
-        // write data
-        for (int i = 0; i < codedText.Length; i++)
-        {
-            completeBitArray[completeBitArrayIndex++] = codedText[i];
-        }
-
-        return completeBitArray;
-    }
-
     /// <summary>
     /// Calculates the Micro QR code data which then can be used in one of the rendering classes to generate a graphical representation.
     /// </summary>

QRCoder/QRCodeGenerator/DataSegment.cs

@@ -32,6 +32,13 @@ private readonly struct DataSegment
         /// </summary>
         public readonly EciMode EciMode;
 
+        /// <summary>
+        /// Initializes a new instance of the DataSegment struct.
+        /// </summary>
+        /// <param name="encodingMode">The encoding mode for this segment (Numeric, Alphanumeric, Byte, etc.)</param>
+        /// <param name="characterCount">The character count (or byte count for byte mode)</param>
+        /// <param name="data">The encoded data as a BitArray</param>
+        /// <param name="eciMode">The ECI mode value (use EciMode.Default if not using ECI)</param>
         public DataSegment(EncodingMode encodingMode, int characterCount, BitArray data, EciMode eciMode)
         {
             EncodingMode = encodingMode;
@@ -51,5 +58,47 @@ public int GetBitLength(int version)
             int countIndicatorLength = GetCountIndicatorLength(version, EncodingMode);
             return modeIndicatorLength + countIndicatorLength + Data.Length;
         }
+
+        /// <summary>
+        /// Builds a complete BitArray from this data segment for a specific QR code version.
+        /// </summary>
+        /// <param name="version">The QR code version (1-40, or -1 to -4 for Micro QR)</param>
+        /// <returns>A BitArray containing the complete encoded segment including mode indicator, count indicator, and data</returns>
+        public BitArray ToBitArray(int version)
+        {
+            var bitArray = new BitArray(GetBitLength(version));
+            WriteTo(bitArray, 0, version);
+            return bitArray;
+        }
+
+        /// <summary>
+        /// Writes this data segment to an existing BitArray at the specified index for a specific QR code version.
+        /// </summary>
+        /// <param name="bitArray">The target BitArray to write to</param>
+        /// <param name="startIndex">The starting index in the BitArray where writing should begin</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 int WriteTo(BitArray bitArray, int startIndex, int version)
+        {
+            var index = startIndex;
+
+            // write eci mode if present
+            if (HasEciMode)
+            {
+                index = DecToBin((int)EncodingMode.ECI, 4, bitArray, index);
+                index = DecToBin((int)EciMode, 8, bitArray, index);
+            }
+            // write mode indicator
+            index = DecToBin((int)EncodingMode, 4, bitArray, index);
+
+            // write count indicator
+            int countIndicatorLength = GetCountIndicatorLength(version, EncodingMode);
+            index = DecToBin(CharacterCount, countIndicatorLength, bitArray, index);
+
+            // write data
+            Data.CopyTo(bitArray, 0, index, Data.Length);
+
+            return index + Data.Length;
+        }
     }
 }