--- /dev/null
+#ifndef BIT_VECTOR_CLASS
+#define BIT_VECTOR_CLASS
+
+/*****************************************************************************\
+* *
+* Name : bit_vector *
+* Author : Chris Koeritz *
+* *
+*******************************************************************************
+* Copyright (c) 1990-$now By Author. This program is free software; you can *
+* redistribute it and/or modify it under the terms of the GNU General Public *
+* License as published by the Free Software Foundation; either version 2 of *
+* the License or (at your option) any later version. This is online at: *
+* http://www.fsf.org/copyleft/gpl.html *
+* Please send any updates to: fred@gruntose.com *
+\*****************************************************************************/
+
+#include <basis/astring.h>
+#include <basis/definitions.h>
+
+namespace structures {
+
+//! An array of bits with operations for manipulating and querying individual bits.
+
+class bit_vector
+{
+public:
+ bit_vector();
+ //!< creates a zero length bit_vector.
+
+ bit_vector(int size, const basis::abyte *initial = NIL);
+ //!< creates a bit_vector able to store "size" bits.
+ /*!< if initial is NIL, the vector is initialized to zero. otherwise, the
+ bits are copied from "initial". "initial" must be large enough for the
+ copying to succeed. */
+
+ bit_vector(const bit_vector &to_copy);
+
+ ~bit_vector();
+
+ bit_vector &operator =(const bit_vector &to_copy);
+
+ int bits() const;
+ //!< returns the number of bits in the vector.
+
+ bool operator [] (int position) const;
+ //!< returns the value of the bit at the position specified.
+
+ bool on(int position) const;
+ //!< returns true if the bit at "position" is set.
+
+ bool off(int position) const;
+ //!< returns true if the bit at "position" is clear.
+
+ void set_bit(int position, bool value);
+ //!< sets the bit at "position" to a particular "value".
+
+ bool whole() const;
+ //!< returns true if entire vector is set.
+
+ bool empty() const;
+ //!< returns true if entire vector is unset.
+
+ int find_first(bool to_find) const;
+ //!< Seeks the first occurrence of "to_find".
+ /*!< locates the position at which a bit equal to to_find is located or it
+ returns common::NOT_FOUND if no bit of that value is in the vector. */
+
+ void light(int position);
+ //!< sets the value of the bit at "position".
+
+ void clear(int position);
+ //!< clears the value of the bit at "position".
+
+ void resize(int size);
+ //!< Changes the size of the bit_vector to "size" bits.
+ /*!< This keeps any bits that still fit. Any new bits are set to zero. */
+
+ void reset(int size);
+ //!< resizes the bit_vector and clears all bits in it.
+
+ bool compare(const bit_vector &that, int start, int stop) const;
+ //!< true if "this" is the same as "that" between "start" and "stop".
+
+ bool operator == (const bit_vector &that) const;
+ //!< returns true if "this" is equal to "that".
+ /*!< neither vector is changed. if the vectors do not have the same size,
+ false is returned. */
+
+ basis::astring text_form() const;
+ //!< prints a nicely formatted list of bits to a string.
+
+ bit_vector subvector(int start, int end) const;
+ //!< Extracts a chunk of the vector between "start" and "end".
+ /*!< Returns a bit_vector that is copied from this one starting at "start"
+ and running until "end". An empty bit vector is returned if the indices
+ are out of range. */
+
+ bool overwrite(int start, const bit_vector &to_write);
+ //!< Stores bits from "to_write" into "this" at "start".
+ /*!< overwrites the contents of this bit_vector with the contents of
+ "to_write", beginning at "start" in this bit_vector. true is returned
+ for a successful write. false will be returned if the "start" is out of
+ range or if "to_write" is too large. */
+
+ basis::un_int get(int start, int size) const;
+ //!< gets a portion of the vector as an unsigned integer.
+ /*!< returns an integer (as interpreted by the operating system) where the
+ pattern of bits in that integer is identical to the bits in this
+ bit_vector, beginning at "start" and including enough bits for an
+ integer of "size" bits. */
+
+ bool set(int start, int size, basis::un_int source);
+ //!< puts the "source" value into the vector at "start".
+ /*!< sets the pattern of bits in this bit_vector beginning at "start"
+ identically to how they are stored in the integer "source", where the
+ integer is expected to be using "size" of its bits. the bits are copied
+ starting from the low end of "source", where the operating system
+ defines what the low end is. true is returned for a successful copying. */
+
+ operator const basis::byte_array &() const;
+ //!< returns a copy of the low-level implementation of the bit vector.
+ /*!< the first bit is stored at the bit in first byte, and so forth. */
+
+private:
+ basis::byte_array *_implementation; //!< holds the real state of the bits.
+ int _number_of_bits; //!< the total number of bits possible in this vector.
+
+ struct two_dim_location { int c_byte; int c_offset; };
+ //!< a two-dimensional position given by byte number and offset within byte.
+
+ two_dim_location into_two_dim(int position) const;
+ /*!< turns a bit position in the vector into a two dimensional position
+ of the byte number and a bit offset within that byte. */
+ bool get_bit(const two_dim_location &pos_in2) const;
+ //!< returns the value of the bit given its two dimensional location.
+ void set_bit(const two_dim_location &pos_in2, bool value);
+ //!< sets the value of the bit if "value", and clears it if not.
+};
+
+//////////////
+
+// NOTE: these are operations on numbers, NOT on bit_vectors.
+
+//! returns a number based on "to_modify" but with "bits" turned on.
+template <class type>
+void SET(type &to_modify, type bits) { to_modify |= bits; }
+
+//! returns a number based on "to_modify" but with "bits" turned off.
+template <class type>
+void CLEAR(type &to_modify, type bits) { to_modify &= (type)~bits; }
+
+//! returns non-zero if the "bits" bit pattern is turned on in "to_test".
+template <class type>
+bool TEST(type to_test, type bits) { return bool(!(!(to_test & bits))); }
+
+//////////////
+
+} //namespace.
+
+#endif
+
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