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diff --git a/Source/Utils/Parser/IntervalsParser.H b/Source/Utils/Parser/IntervalsParser.H
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+/* Copyright 2022 Andrew Myers, Burlen Loring, Luca Fedeli
+ * Maxence Thevenet, Remi Lehe, Revathi Jambunathan
+ *
+ * This file is part of WarpX.
+ *
+ * License: BSD-3-Clause-LBNL
+ */
+
+#ifndef WARPX_UTILS_PARSER_INTERVALSPARSER_H_
+#define WARPX_UTILS_PARSER_INTERVALSPARSER_H_
+
+#include <limits>
+#include <string>
+#include <vector>
+
+namespace utils::parser
+{
+
+    /**
+     * \brief This class is a parser for slices of the form i:j:k where i, j and k are integers
+     * representing respectively the starting point, the stopping point and the period.
+     */
+    class SliceParser
+    {
+    public:
+        /**
+        * \brief Constructor of the SliceParser class.
+        *
+        * @param[in] instr an input string of the form "i:j:k", "i:j" or "k" where i, j and k are
+        * integers representing respectively the starting point, the stopping point and the period.
+        * Any of these integers may be omitted in which case it will be equal to their default value
+        * (0 for the starting point, std::numeric_limits<int>::max() for the stopping point and 1 for
+        * the period). For example SliceParser(":1000:") is equivalent to SliceParser("0:1000:1").
+        */
+        SliceParser (const std::string& instr, bool isBTD=false);
+
+        /**
+        * \brief A method that returns true if the input integer is contained in the slice. (e.g. if
+        * the list is initialized with "300:500:100", this method returns true if and only if n is
+        * 300, 400 or 500). If the period is negative or 0, the function always returns false.
+        *
+        * @param[in] n the input integer
+        */
+        bool contains (const int n) const;
+
+        /**
+        * \brief A method that returns the smallest integer strictly greater than n such that
+        * contains(n) is true. Returns std::numeric_limits<int>::max() if there is no such integer.
+        *
+        * @param[in] n the input integer
+        */
+        int nextContains (const int n) const;
+
+        /**
+        * \brief A method that returns the greatest integer strictly smaller than n such that
+        * contains(n) is true. Returns 0 if there is no such integer.
+        *
+        * @param[in] n the input integer
+        */
+        int previousContains (const int n) const;
+
+        /**
+        * \brief A method that returns the slice period.
+        *
+        */
+        int getPeriod () const;
+
+        /**
+        * \brief A method that returns the slice start.
+        *
+        */
+        int getStart () const;
+
+        /**
+        * \brief A method that returns the slice stop.
+        *
+        */
+        int getStop () const;
+
+        /**
+        * @brief A method that returns the number of integers contained by the slice.
+        *
+        */
+        int numContained() const;
+
+    private:
+        bool m_isBTD = false;
+        int m_start = 0;
+        int m_stop = std::numeric_limits<int>::max();
+        int m_period = 1;
+        std::string m_separator = ":";
+
+    };
+
+
+    /**
+     * \brief This class is a parser for multiple slices of the form x,y,z,... where x, y and z are
+     * slices of the form i:j:k, as defined in the SliceParser class. This class contains a vector of
+     * SliceParsers.
+     */
+    class IntervalsParser
+    {
+    public:
+        /**
+        * \brief Default constructor of the IntervalsParser class.
+        */
+        IntervalsParser () = default;
+
+        /**
+        * \brief Constructor of the IntervalsParser class.
+        *
+        * @param[in] instr_vec an input vector string, which when concatenated is of the form
+        * "x,y,z,...". This will call the constructor of SliceParser using x, y and z as input
+        * arguments.
+        */
+        IntervalsParser (const std::vector<std::string>& instr_vec);
+
+        /**
+        * \brief A method that returns true if the input integer is contained in any of the slices
+        * contained by the IntervalsParser.
+        *
+        * @param[in] n the input integer
+        */
+        bool contains (const int n) const;
+
+        /**
+        * \brief A method that returns the smallest integer strictly greater than n such that
+        * contains(n) is true. Returns std::numeric_limits<int>::max() if there is no such integer.
+        *
+        * @param[in] n the input integer
+        */
+        int nextContains (const int n) const;
+
+        /**
+        * \brief A method that returns the greatest integer strictly smaller than n such that
+        * contains(n) is true. Returns 0 if there is no such integer.
+        *
+        * @param[in] n the input integer
+        */
+        int previousContains (const int n) const;
+
+        /**
+        * \brief A method that returns the greatest integer smaller than or equal to n such that
+        * contains(n) is true. Returns 0 if there is no such integer.
+        *
+        * @param[in] n the input integer
+        */
+        int previousContainsInclusive (const int n) const;
+
+        /**
+        * \brief A method the local period (in timesteps) of the IntervalsParser at timestep n.
+        * The period is defined by nextContains(n) - previousContainsInclusive(n)
+        *
+        * @param[in] n the input integer
+        */
+        int localPeriod (const int n) const;
+
+        /**
+        * \brief A method that returns true if any of the slices contained by the IntervalsParser
+        * has a strictly positive period.
+        */
+        bool isActivated () const;
+
+    private:
+        std::vector<SliceParser> m_slices;
+        std::string m_separator = ",";
+        bool m_activated = false;
+    };
+
+    /**
+     * \brief This class is a parser for multiple slices of the form x,y,z,... where x, y and z are
+     * slices of the form i:j:k, as defined in the SliceParser class. This class contains a vector of
+     * SliceParsers. The supported function set differs from the IntervalsParser
+     */
+    class BTDIntervalsParser
+    {
+    public:
+        /**
+        * \brief Default constructor of the BTDIntervalsParser class.
+        */
+        BTDIntervalsParser () = default;
+
+        /**
+        * \brief Constructor of the BTDIntervalsParser class.
+        *
+        * @param[in] instr_vec an input vector string, which when concatenated is of the form
+        * "x,y,z,...". This will call the constructor of SliceParser using x, y and z as input
+        * arguments.
+        */
+        BTDIntervalsParser (const std::vector<std::string>& instr_vec);
+
+        /**
+         * @brief Return the total number of unique labframe snapshots
+         */
+        int NumSnapshots ();
+
+        /**
+         * @brief Return the iteration number stored at index i_buffer
+         *
+         * @param i_buffer buffer or iteration index, between 0 and NumSnapshots
+         */
+        int GetBTDIteration(int i_buffer);
+
+        /**
+        * \brief A method that returns true if any of the slices contained by the IntervalsParser
+        * has a strictly positive period.
+        */
+        bool isActivated () const;
+
+    private:
+        std::vector<int> m_btd_iterations;
+        std::vector<SliceParser> m_slices;
+        std::vector<int> m_slice_starting_i_buffer;
+        int m_n_snapshots;
+        static constexpr char m_separator = ',';
+        bool m_activated = false;
+    };
+}
+
+#endif // WARPX_UTILS_PARSER_INTERVALSPARSER_H_