diff --git a/src/util/hei_bit_string.cpp b/src/util/hei_bit_string.cpp
index 53a4d4c..bf1dfdd 100644
--- a/src/util/hei_bit_string.cpp
+++ b/src/util/hei_bit_string.cpp
@@ -2,7 +2,7 @@
  *  @brief BitString and BitStringBuffer class definitions
  */
 
-#include <hei_bit_string.hpp>
+#include <util/hei_bit_string.hpp>
 #include <util/hei_includes.hpp>
 
 #include <algorithm>
diff --git a/src/util/hei_bit_string.hpp b/src/util/hei_bit_string.hpp
new file mode 100644
index 0000000..59369b7
--- /dev/null
+++ b/src/util/hei_bit_string.hpp
@@ -0,0 +1,461 @@
+#pragma once
+
+#include <stdint.h>
+
+namespace libhei
+{
+
+class BitStringBuffer;
+
+//##############################################################################
+//                             BitString class
+//##############################################################################
+
+/**
+ * A BitString is general purpose class providing the ability to manipulate
+ * individual bits within an allocated section of contiguous memory.
+ *
+ * A BitString does not "own" the memory, it only accesses and manipulates the
+ * bits in the range specified. Users will need to ensure memory is allocated
+ * and deallocated appropriately. As an alternative, a BitStringBuffer is a
+ * BitString that will allocate and maintain its own memory.
+ *
+ * The length of a BitString is only limited by the amount of memory that
+ * contains the data buffer.
+ *
+ * !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! IMPORTANT !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
+ *
+ *  - The bit positions are ordered 0 to n (left to right), where n is the bit
+ *    length minus one.
+ *  - The data stored in memory is assumed to be in big-endian byte format.
+ *
+ * So, for example:
+ *
+ *    uint8_t a[2];                       // 16 bits of memory
+ *    BitString bs { 16, a };             // init BitString for a
+ *    bs.setFieldRight(0, 16, 0x1122);  // set all 16 bits to 0x1122
+ *
+ * Results in:
+ *
+ *    a[0] == bs.getFieldRight(0, 8) (i.e. 0x11)
+ *    a[1] == bs.getFieldRight(8, 8) (i.e. 0x22)
+ *
+ * It is very important you do NOT do this:
+ *
+ *    uint16_t x = 0x1122;      // 16 bits of memory
+ *    BitString bs { 16, &x };  // init BitString for x
+ *
+ * The results are undefined, or at least not portable. For example:
+ *
+ *   Big-endian:
+ *      x is stored in memory as |0x11|0x22|.
+ *      Therefore, bs.getFieldRight(0, 8) returns 0x11.
+ *
+ *   Little-endian:
+ *      x is stored in memory as |0x22|0x11|.
+ *      Therefore, bs.getFieldRight(0, 8) returns 0x22.
+ *
+ */
+class BitString
+{
+  private: // constants
+    static const uint64_t UINT64_BIT_LEN;
+    static const uint64_t UINT8_BIT_LEN;
+
+  public: // functions
+    /**
+     * @brief Constructor
+     * @param i_bitLen  The number of bits in the bit string.
+     * @param i_bufAddr The starting address of the memory buffer.
+     * @param i_offset  By default, position 0 will be the first bit of the
+     *                  buffer's start address. However, this parameter can be
+     *                  used to indicate that position 0 actually starts
+     *                  somewhere in the middle of the buffer.
+     * @pre   Use getMinBytes() to calulate the minimum number of bytes needed
+     *        to allocate sufficient memory space for this bit string.
+     */
+    BitString(uint64_t i_bitLen, void* i_bufAddr, uint64_t i_offset = 0) :
+        iv_bitLen(i_bitLen), iv_bufAddr(i_bufAddr), iv_offset(i_offset)
+    {}
+
+    /** @brief Destructor */
+    virtual ~BitString() {}
+
+    /** @return The number of bits in the bit string buffer. */
+    uint64_t getBitLen() const
+    {
+        return iv_bitLen;
+    }
+
+    /** @return The address of the bit string buffer. Note that this may
+     *          return nullptr. */
+    void* getBufAddr() const
+    {
+        return iv_bufAddr;
+    }
+
+    /**
+     * @param i_bitLen The number of bits for a bit string.
+     * @param i_offset Optional starting position of the bit string within the
+     *                 memory buffer.
+     * @return The minimum number of bytes required to allocate sufficient
+     *         memory space for a bit string.
+     */
+    static uint64_t getMinBytes(uint64_t i_bitLen, uint64_t i_offset = 0)
+    {
+        return (i_bitLen + i_offset + UINT8_BIT_LEN - 1) / UINT8_BIT_LEN;
+    }
+
+    /**
+     * @brief  Returns a left-justified value of the given length from the bit
+     *         string starting at the given position.
+     * @param  i_pos The starting position of the target range.
+     * @param  i_len The number of bits of the target range.
+     * @return The value of the field range specified (left-justified).
+     * @pre    nullptr != getBufAddr()
+     * @pre    0 < i_len
+     * @pre    i_len <= UINT64_BIT_LEN
+     * @pre    i_pos + i_len <= getBitLen()
+     */
+    uint64_t getFieldLeft(uint64_t i_pos, uint64_t i_len) const
+    {
+        return getFieldRight(i_pos, i_len) << (UINT64_BIT_LEN - i_len);
+    }
+
+    /**
+     * @brief  Returns a right-justified value of the given length from the bit
+     *         string starting at the given position.
+     * @param  i_pos The starting position of the target range.
+     * @param  i_len The number of bits of the target range.
+     * @return The value of the field range specified (right-justified).
+     * @pre    nullptr != getBufAddr()
+     * @pre    0 < i_len
+     * @pre    i_len <= UINT64_BIT_LEN
+     * @pre    i_pos + i_len <= getBitLen()
+     */
+    uint64_t getFieldRight(uint64_t i_pos, uint64_t i_len) const;
+
+    /**
+     * @brief  Sets a left-justified value of the given length into the bit
+     *         string starting at the given position.
+     * @param i_pos The starting position of the target range.
+     * @param i_len The number of bits of the target range.
+     * @param i_val The left-justified value to set.
+     * @pre   nullptr != getBufAddr()
+     * @pre   0 < i_len
+     * @pre   i_len <= UINT64_BIT_LEN
+     * @pre   i_pos + i_len <= getBitLen()
+     */
+    void setFieldLeft(uint64_t i_pos, uint64_t i_len, uint64_t i_val);
+
+    /**
+     * @brief  Sets a right-justified value of the given length into the bit
+     *         string starting at the given position.
+     * @param i_pos The starting position of the target range.
+     * @param i_len The number of bits of the target range.
+     * @param i_val The right-justified value to set.
+     * @pre   nullptr != getBufAddr()
+     * @pre   0 < i_len
+     * @pre   i_len <= UINT64_BIT_LEN
+     * @pre   i_pos + i_len <= getBitLen()
+     */
+    void setFieldRight(uint64_t i_pos, uint64_t i_len, uint64_t i_val)
+    {
+        setFieldLeft(i_pos, i_len, i_val << (UINT64_BIT_LEN - i_len));
+    }
+
+    /**
+     * @param  i_pos The target position.
+     * @return True if the bit at the given position is set(1), false otherwise.
+     * @pre    i_pos < getBitLen().
+     */
+    bool isBitSet(uint64_t i_pos) const
+    {
+        return 0 != getFieldRight(i_pos, 1);
+    }
+
+    /**
+     * @brief Sets the target position to 1.
+     * @param i_pos The target position.
+     * @pre   i_pos < getBitLen().
+     */
+    void setBit(uint64_t i_pos)
+    {
+        setFieldRight(i_pos, 1, 1);
+    }
+
+    /** @brief Sets the entire bit string to 1's. */
+    void setAll()
+    {
+        setPattern(UINT64_MAX);
+    }
+
+    /**
+     * @brief Sets the target position to 0.
+     * @param i_pos The target position.
+     * @pre   i_pos < getBitLen().
+     */
+    void clearBit(uint64_t i_pos)
+    {
+        setFieldRight(i_pos, 1, 0);
+    }
+
+    /** @brief Sets the entire bit string to 0's. */
+    void clearAll()
+    {
+        setPattern(0);
+    }
+
+    /**
+     * @brief Sets a range within the string based on the pattern and length
+     *        provided.
+     * @param i_sPos    Starting position of this string.
+     * @param i_sLen    The length of the target range.
+     * @param i_pattern The pattern to set (right justified).
+     * @param i_pLen    The length of the pattern.
+     * @pre   nullptr != getBufAddr()
+     * @pre   0 < i_sLen
+     * @pre   i_sPos + i_sLen <= getBitLen()
+     * @pre   0 < i_pLen <= UINT64_BIT_LEN
+     * @post  The pattern is repeated/truncated as needed.
+     *
+     * Examples:  i_sPos(0), i_sLen(10), i_pattern(0xA), i_pLen(4)
+     *            Old String: 0000000000
+     *            New String: 1010101010
+     *
+     *            i_sPos(3), i_sLen(4), i_pattern(0x3), i_pLen(3)
+     *            Old String: 0001001000
+     *            New String: 0000110000
+     */
+    void setPattern(uint64_t i_sPos, uint64_t i_sLen, uint64_t i_pattern,
+                    uint64_t i_pLen);
+
+    /**
+     * @brief Sets entire string based on the pattern and length provided.
+     * @param i_pattern The pattern to set (right justified).
+     * @param i_pLen    The length of the pattern.
+     * @note  See definition above for prerequisites.
+     * @post  The entire string is filled with the pattern.
+     * @post  The pattern is repeated/truncated as needed.
+     */
+    void setPattern(uint64_t i_pattern, uint64_t i_pLen)
+    {
+        setPattern(0, getBitLen(), i_pattern, i_pLen);
+    }
+
+    /**
+     * @brief Sets entire string based on the pattern provided.
+     * @param i_pattern The pattern to set (right justified).
+     * @note  See definition above for prerequisites.
+     * @post  The entire string is filled with the pattern.
+     * @post  The pattern is repeated/truncated as needed.
+     */
+    void setPattern(uint64_t i_pattern)
+    {
+        setPattern(i_pattern, sizeof(i_pattern) * 8);
+    }
+
+    /**
+     * @brief Set bits in this string based on the given string.
+     * @param i_sStr The source string.
+     * @param i_sPos The starting position of the source string.
+     * @param i_sLen The number of bits to copy from the source string.
+     * @param i_dPos The starting position of the this string.
+     * @pre   nullptr != getBufAddr()
+     * @pre   nullptr != i_sStr.getBufAddr()
+     * @pre   0 < i_sLen
+     * @pre   i_sPos + i_sLen <= i_sStr.getBitLen()
+     * @pre   i_dPos < getBitLen()
+     * @post  Source bits in given range are copied to this starting at i_dPos.
+     * @note  If the length of the given string is greater than the length of
+     *        this string, then the extra bits are ignored.
+     * @note  If the length of the given string is less than the length of this
+     *        string, then the extra bits in this string are not modified.
+     * @note  This string and the source string may specify overlapping memory.
+     */
+    void setString(const BitString& i_sStr, uint64_t i_sPos, uint64_t i_sLen,
+                   uint64_t i_dPos = 0);
+
+    /**
+     * @brief Set bits in this string based on the provided string.
+     * @param i_sStr The source string.
+     * @note  This will try to copy as much of the source as possible to this
+     *        string, starting with the first bit in each string.
+     * @note  See the other definition of this function for details and
+     *        restrictions.
+     */
+    void setString(const BitString& i_sStr)
+    {
+        setString(i_sStr, 0, i_sStr.getBitLen());
+    }
+
+    /**
+     * @brief Masks (clears) any bits set in this string that correspond to bits
+     *        set in the given string (this & ~mask).
+     * @param i_mask The mask string (right justified).
+     * @note  If the length of the given string is greater than the length of
+     *        this string, then the extra bits are ignored.
+     * @note  If the length of the given string is less than the length of this
+     *        string, then the extra bits in this string are not modified.
+     */
+    void maskString(const BitString& i_mask);
+
+    /**
+     * @param  i_str The string to compare.
+     * @return True if the strings are equivalent, false otherwise.
+     * @pre    Both strings must be of equal length and have same values to be
+     *         equal.
+     */
+    bool isEqual(const BitString& i_str) const;
+
+    /** @return True if there are no bit set(1) in this bit string, false
+     *          otherwise. */
+    bool isZero() const;
+
+    /**
+     * @param  i_pos The starting position of the target range.
+     * @param  i_len The length of the target range.
+     * @return The number of bits that are set(1) in given range of this string.
+     * @pre    nullptr != getBufAddr()
+     * @pre    i_pos + i_len <= getBitLen()
+     */
+    uint64_t getSetCount(uint64_t i_pos, uint64_t i_len) const;
+
+    /** @return The number of bits that are set(1) in this string. */
+    uint64_t getSetCount() const
+    {
+        return getSetCount(0, getBitLen());
+    }
+
+    /** @brief Comparison operator. */
+    bool operator==(const BitString& i_str) const
+    {
+        return isEqual(i_str);
+    }
+
+    /**
+     * @brief Less-than operator.
+     *
+     * IMPORTANT:
+     * The purpose of this function is primarily for sorting these objects in
+     * data structures like map and vector. It does not guarantee a less than
+     * comparison of the bit strings because bit strings can vary in length and
+     * it is difficult to define that kind of comparison.
+     */
+    bool operator<(const BitString& i_str) const;
+
+    /** @brief Bitwise NOT operator. */
+    BitStringBuffer operator~() const;
+
+    /** @brief Bitwise AND operator. */
+    BitStringBuffer operator&(const BitString& i_bs) const;
+
+    /** @brief Bitwise OR operator. */
+    BitStringBuffer operator|(const BitString& i_bs) const;
+
+    /** @brief Right shift operator. */
+    BitStringBuffer operator>>(uint64_t i_shift) const;
+
+    /** @brief Left shift operator. */
+    BitStringBuffer operator<<(uint64_t i_shift) const;
+
+    /**
+     * @brief Explicitly disables copy from BitString.
+     *
+     * Prevents assigning a BitString& to a BitString, which would strip
+     * polymorphism.
+     */
+    BitString(const BitString& i_bs) = delete;
+
+    /**
+     * @brief Explicitly disables assignment from BitStringBuffer.
+     *
+     * Allowing this would be dangerous if the BitStringBuffer goes out of scope
+     * because the BitString would point to memory that is no longer in context.
+     */
+    BitString& operator=(const BitStringBuffer& i_bsb) = delete;
+
+    /**
+     * @brief Explicitly disables copy from BitStringBuffer.
+     *
+     * Allowing this would be dangerous if the BitStringBuffer goes out of scope
+     * because the BitString would point to memory that is no longer in context.
+     */
+    BitString(const BitStringBuffer& i_bsb) = delete;
+
+  protected: // functions
+    /**
+     * @param i_newBufAddr The starting address of the new bit string buffer.
+     * @pre   Before calling this function, make sure you deallocate the old
+     *        buffer to avoid memory leaks.
+     */
+    void setBufAddr(void* i_newBufAddr)
+    {
+        iv_bufAddr = i_newBufAddr;
+    }
+
+    /** @param i_newBitLen The new bit length of this bit string buffer. */
+    void setBitLen(uint64_t i_newBitLen)
+    {
+        iv_bitLen = i_newBitLen;
+    }
+
+  private: // functions
+    /**
+     * @brief  Given a bit position within the bit string, this function returns
+     *         the address that contains the bit position and the bit position
+     *         relative to that address.
+     * @param  o_relPos The returned relative position.
+     * @param  i_absPos The inputted absolute position.
+     * @return The relative address.
+     * @pre    nullptr != getBufAddr()
+     * @pre    i_absPos < getBitLen()
+     */
+    uint8_t* getRelativePosition(uint64_t& o_relPos, uint64_t i_absPos) const;
+
+  private:
+    uint64_t iv_bitLen; ///< The bit length of this buffer.
+    void* iv_bufAddr;   ///< The beginning address of this buffer.
+    uint64_t iv_offset; ///< Start position offset
+};
+
+//##############################################################################
+//                          BitStringBuffer class
+//##############################################################################
+
+/** A BitStringBuffer is a BitString that maintains its own buffer in memory. It
+ *  guarantees that sufficient memory is allocated and deallocated in the
+ *  constructor and destructor, respectively. In addition, the assignment
+ *  operator will adjust the amount of memory needed, as necessary, for the
+ *  assignment. */
+class BitStringBuffer : public BitString
+{
+  public: // functions
+    /**
+     * @brief Constructor
+     * @param i_bitLen Number of bits in the string.
+     */
+    explicit BitStringBuffer(uint64_t i_bitLen);
+
+    /** @brief Destructor */
+    ~BitStringBuffer();
+
+    /** @brief Copy constructor from BitString */
+    explicit BitStringBuffer(const BitString& i_bs);
+
+    /** @brief Copy constructor from BitStringBuffer */
+    BitStringBuffer(const BitStringBuffer& i_bsb);
+
+    /** @brief Assignment from BitString */
+    BitStringBuffer& operator=(const BitString& i_bs);
+
+    /** @brief Assignment from BitStringBuffer */
+    BitStringBuffer& operator=(const BitStringBuffer& i_bsb);
+
+  private: // functions
+    /** @brief Deallocates the old buffer, if needed, and initializes the new
+     *         buffer. */
+    void initBuffer();
+};
+
+} // end namespace libhei