/*       +------------------------------------+
 *       | Inspire Internet Relay Chat Daemon |
 *       +------------------------------------+
 *
 *  InspIRCd: (C) 2002-2007 InspIRCd Development Team
 * See: http://www.inspircd.org/wiki/index.php/Credits
 *
 * This program is free but copyrighted software; see
 *            the file COPYING for details.
 *
 * ---------------------------------------------------
 */

#ifndef _HASHCOMP_H_
#define _HASHCOMP_H_

#include "inspircd_config.h"
#include "socket.h"
#include "hash_map.h"

/*******************************************************
 * This file contains classes and templates that deal
 * with the comparison and hashing of 'irc strings'.
 * An 'irc string' is a string which compares in a
 * case insensitive manner, and as per RFC 1459 will
 * treat [ identical to {, ] identical to }, and \
 * as identical to |.
 *
 * Our hashing functions are designed  to accept
 * std::string and compare/hash them as type irc::string
 * by converting them internally. This makes them
 * backwards compatible with other code which is not
 * aware of irc::string.
 *******************************************************/
 
using namespace std;
using irc::sockets::insp_aton;
using irc::sockets::insp_ntoa;

#ifndef LOWERMAP
#define LOWERMAP
/** A mapping of uppercase to lowercase, including scandinavian
 * 'oddities' as specified by RFC1459, e.g. { -> [, and | -> \
 */
unsigned const char lowermap[256] = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19,				/* 0-19 */
				20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39,				/* 20-39 */
				40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59,				/* 40-59 */
				60, 61, 62, 63, 64, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111,		/* 60-79 */
				112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 94, 95, 96, 97, 98, 99,		/* 80-99 */
				100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119,	/* 100-119 */
				120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133, 134, 135, 136, 137, 138, 139,	/* 120-139 */
				140, 141, 142, 143, 144, 145, 146, 147, 148, 149, 150, 151, 152, 153, 154, 155, 156, 157, 158, 159,	/* 140-159 */
				160, 161, 162, 163, 164, 165, 166, 167, 168, 169, 170, 171, 172, 173, 174, 175, 176, 177, 178, 179,	/* 160-179 */
				180, 181, 182, 183, 184, 185, 186, 187, 188, 189, 190, 191, 192, 193, 194, 195, 196, 197, 198, 199,	/* 180-199 */
				200, 201, 202, 203, 204, 205, 206, 207, 208, 209, 210, 211, 212, 213, 214, 215, 216, 217, 218, 219,	/* 200-219 */
				220, 221, 222, 223, 224, 225, 226, 227, 228, 229, 230, 231, 232, 233, 234, 235, 236, 237, 238, 239,	/* 220-239 */
				240, 241, 242, 243, 244, 245, 246, 247, 248, 249, 250, 251, 252, 253, 254, 255				/* 240-255 */
};
#endif

/** Because of weirdness in g++, before 3.x this was namespace std. It's now __gnu_cxx.
 * This is a #define'd alias.
 */
namespace nspace
{
	/** Convert a string to lower case respecting RFC1459
	 * @param n A string to lowercase
	 */
	void strlower(char *n);

	/** Hashing function to hash std::string without respect to case
	 */
        template<> struct hash<std::string>
        {
		/** Hash a std::string using RFC1459 case sensitivity rules
		 * @param s A string to hash
		 * @return The hash value
		 */
                size_t operator()(const string &s) const;
        };
}

/** The irc namespace contains a number of helper classes.
 */
namespace irc
{

	/** This class returns true if two strings match.
	 * Case sensitivity is ignored, and the RFC 'character set'
	 * is adhered to
	 */
	struct StrHashComp
	{
		/** The operator () does the actual comparison in hash_map
		 */
	        bool operator()(const std::string& s1, const std::string& s2) const;
	};


	/** irc::stringjoiner joins string lists into a string, using
	 * the given seperator string.
	 * This class can join a vector of std::string, a deque of
	 * std::string, or a const char** array, using overloaded
	 * constructors.
	 */
	class stringjoiner
	{
	 private:
		/** Output string
		 */
		std::string joined;
	 public:
		/** Join elements of a vector, between (and including) begin and end
		 * @param seperator The string to seperate values with
		 * @param sequence One or more items to seperate
		 * @param begin The starting element in the sequence to be joined
		 * @param end The ending element in the sequence to be joined
		 */
		stringjoiner(const std::string &seperator, const std::vector<std::string> &sequence, int begin, int end);
		/** Join elements of a deque, between (and including) begin and end
		 * @param seperator The string to seperate values with
		 * @param sequence One or more items to seperate
		 * @param begin The starting element in the sequence to be joined
		 * @param end The ending element in the sequence to be joined
		 */
		stringjoiner(const std::string &seperator, const std::deque<std::string> &sequence, int begin, int end);
		/** Join elements of an array of char arrays, between (and including) begin and end
		 * @param seperator The string to seperate values with
		 * @param sequence One or more items to seperate
		 * @param begin The starting element in the sequence to be joined
		 * @param end The ending element in the sequence to be joined
		 */
		stringjoiner(const std::string &seperator, const char** sequence, int begin, int end);

		/** Get the joined sequence
		 * @return A reference to the joined string
		 */
		std::string& GetJoined();
	};

	/** irc::modestacker stacks mode sequences into a list.
	 * It can then reproduce this list, clamped to a maximum of MAXMODES
	 * values per line.
	 */
	class modestacker
	{
	 private:
		/** The mode sequence and its parameters
		 */
		std::deque<std::string> sequence;
		/** True if the mode sequence is initially adding
		 * characters, false if it is initially removing
		 * them
		 */
		bool adding;
	 public:
		/** Construct a new modestacker.
		 * @param add True if the stack is adding modes,
		 * false if it is removing them
		 */
		modestacker(bool add);
		/** Push a modeletter and its parameter onto the stack.
		 * No checking is performed as to if this mode actually
		 * requires a parameter. If you stack invalid mode
		 * sequences, they will be tidied if and when they are
		 * passed to a mode parser.
		 * @param modeletter The mode letter to insert
		 * @param parameter The parameter for the mode
		 */
		void Push(char modeletter, const std::string &parameter);
		/** Push a modeletter without parameter onto the stack.
		 * No checking is performed as to if this mode actually
		 * requires a parameter. If you stack invalid mode
		 * sequences, they will be tidied if and when they are
		 * passed to a mode parser.
		 * @param modeletter The mode letter to insert
		 */
		void Push(char modeletter);
		/** Push a '+' symbol onto the stack.
		 */
		void PushPlus();
		/** Push a '-' symbol onto the stack.
		 */
		void PushMinus();
		/** Return zero or more elements which form the
		 * mode line. This will be clamped to a max of
		 * MAXMODES+1 items (MAXMODES mode parameters and
		 * one mode sequence string), and max_line_size
		 * characters. As specified below, this function
		 * should be called in a loop until it returns zero,
		 * indicating there are no more modes to return.
		 * @param result The deque to populate. This will
		 * be cleared before it is used.
		 * @param max_line_size The maximum size of the line
		 * to build, in characters, seperate to MAXMODES.
		 * @return The number of elements in the deque.
		 * The function should be called repeatedly until it
		 * returns 0, in case there are multiple lines of
		 * mode changes to be obtained.
		 */
		int GetStackedLine(std::deque<std::string> &result, int max_line_size = 360);
	};

	/** irc::tokenstream reads a string formatted as per RFC1459 and RFC2812.
	 * It will split the string into 'tokens' each containing one parameter
	 * from the string.
	 * For instance, if it is instantiated with the string:
	 * "PRIVMSG #test :foo bar baz qux"
	 * then each successive call to tokenstream::GetToken() will return
	 * "PRIVMSG", "#test", "foo bar baz qux", "".
	 * Note that if the whole string starts with a colon this is not taken
	 * to mean the string is all one parameter, and the first item in the
	 * list will be ":item". This is to allow for parsing 'source' fields
	 * from data.
	 */
	class tokenstream
	{
	 private:
		/** Original string
		 */
		std::string tokens;
		/** Last position of a seperator token
		 */
		std::string::iterator last_starting_position;
		/** Current string position
		 */
		std::string::iterator n;
		/** True if the last value was an ending value
		 */
		bool last_pushed;
	 public:
		/** Create a tokenstream and fill it with the provided data
		 */
		tokenstream(const std::string &source);
		~tokenstream();

		/** Fetch the next token from the stream
		 * @return The next token is returned, or an empty string if none remain
		 */
		const std::string GetToken();
	};

	/** irc::sepstream allows for splitting token seperated lists.
	 * Each successive call to sepstream::GetToken() returns
	 * the next token, until none remain, at which point the method returns
	 * an empty string.
	 */
	class sepstream : public classbase
	{
	 private:
		/** Original string
		 */
		std::string tokens;
		/** Last position of a seperator token
		 */
		std::string::iterator last_starting_position;
		/** Current string position
		 */
		std::string::iterator n;
		/** Seperator value
		 */
		char sep;
	 public:
		/** Create a sepstream and fill it with the provided data
		 */
		sepstream(const std::string &source, char seperator);
		virtual ~sepstream();

		/** Fetch the next token from the stream
		 * @return The next token is returned, or an empty string if none remain
		 */
		virtual const std::string GetToken();
		
		/** Fetch the entire remaining stream, without tokenizing
		 * @return The remaining part of the stream
		 */
		virtual const std::string GetRemaining();
		
		/** Returns true if the end of the stream has been reached
		 * @return True if the end of the stream has been reached, otherwise false
		 */
		virtual bool StreamEnd();
	};

	/** A derived form of sepstream, which seperates on commas
	 */
	class commasepstream : public sepstream
	{
	 public:
		commasepstream(const std::string &source) : sepstream(source, ',')
		{
		}
	};

	/** A derived form of sepstream, which seperates on spaces
	 */
	class spacesepstream : public sepstream
	{
	 public:
		spacesepstream(const std::string &source) : sepstream(source, ' ')
		{
		}
	};

	/** The portparser class seperates out a port range into integers.
	 * A port range may be specified in the input string in the form
	 * "6660,6661,6662-6669,7020". The end of the stream is indicated by
	 * a return value of 0 from portparser::GetToken(). If you attempt
	 * to specify an illegal range (e.g. one where start >= end, or
	 * start or end < 0) then GetToken() will return the first element
	 * of the pair of numbers.
	 */
	class portparser : public classbase
	{
	 private:
		/** Used to split on commas
		 */
		commasepstream* sep;
		/** Current position in a range of ports
		 */
		long in_range;
		/** Starting port in a range of ports
		 */
		long range_begin;
		/** Ending port in a range of ports
		 */
		long range_end;
		/** Allow overlapped port ranges
		 */
		bool overlapped;
		/** Used to determine overlapping of ports
		 * without O(n) algorithm being used
		 */
		std::map<long, bool> overlap_set;
		/** Returns true if val overlaps an existing range
		 */
		bool Overlaps(long val);
	 public:
		/** Create a portparser and fill it with the provided data
		 * @param source The source text to parse from
		 * @param allow_overlapped Allow overlapped ranges
		 */
		portparser(const std::string &source, bool allow_overlapped = true);
		/** Frees the internal commasepstream object
		 */
		~portparser();
		/** Fetch the next token from the stream
		 * @return The next port number is returned, or 0 if none remain
		 */
		long GetToken();
	};

	/** Used to hold a bitfield definition in dynamicbitmask.
	 * You must be allocated one of these by dynamicbitmask::Allocate(),
	 * you should not fill the values yourself!
	 */
	typedef std::pair<size_t, unsigned char> bitfield;

	/** The irc::dynamicbitmask class is used to maintain a bitmap of
	 * boolean values, which can grow to any reasonable size no matter
	 * how many bitfields are in it.
	 *
	 * It starts off at 32 bits in size, large enough to hold 32 boolean
	 * values, with a memory allocation of 8 bytes. If you allocate more
	 * than 32 bits, the class will grow the bitmap by 8 bytes at a time
	 * for each set of 8 bitfields you allocate with the Allocate()
	 * method.
	 *
	 * This method is designed so that multiple modules can be allocated
	 * bit values in a bitmap dynamically, rather than having to define
	 * costs in a fixed size unsigned integer and having the possibility
	 * of collisions of values in different third party modules.
	 *
	 * IMPORTANT NOTE:
	 *
	 * To use this class, you must derive from it.
	 * This is because each derived instance has its own freebits array
	 * which can determine what bitfields are allocated on a TYPE BY TYPE
	 * basis, e.g. an irc::dynamicbitmask type for userrecs, and one for
	 * chanrecs, etc. You should inheret it in a very simple way as follows.
	 * The base class will resize and maintain freebits as required, you are
	 * just required to make the pointer static and specific to this class
	 * type.
	 *
	 * \code
	 * class mydbitmask : public irc::dynamicbitmask
	 * {
	 *  private:
	 *
	 *      static unsigned char* freebits;
	 *
	 *  public:
	 *
	 *      mydbitmask() : irc::dynamicbitmask()
	 *      {
	 *          freebits = new unsigned char[this->bits_size];
	 *          memset(freebits, 0, this->bits_size);
	 *      }
	 *
	 *      ~mydbitmask()
	 *      {
	 *          delete[] freebits;
	 *      }
	 *
	 *      unsigned char* GetFreeBits()
	 *      {
	 *          return freebits;
	 *      }
	 *
	 *      void SetFreeBits(unsigned char* freebt)
	 *      {
	 *          freebits = freebt;
	 *      }
	 * };
	 * \endcode
	 */
	class dynamicbitmask : public classbase
	{
	 private:
		/** Data bits. We start with four of these,
		 * and we grow the bitfield as we allocate
		 * more than 32 entries with Allocate().
		 */
		unsigned char* bits;
	 protected:
		/** Current set size (size of freebits and bits).
		 * Both freebits and bits will ALWAYS be the
		 * same length.
		 */
		unsigned char bits_size;
	 public:
		/** Allocate the initial memory for bits and
		 * freebits and zero the memory.
		 */
		dynamicbitmask();

		/** Free the memory used by bits and freebits
		 */
		virtual ~dynamicbitmask();

		/** Allocate an irc::bitfield.
		 * @return An irc::bitfield which can be used
		 * with Get, Deallocate and Toggle methods.
		 * @throw Can throw std::bad_alloc if there is
		 * no ram left to grow the bitmask.
		 */
		bitfield Allocate();

		/** Deallocate an irc::bitfield.
		 * @param An irc::bitfield to deallocate.
		 * @return True if the bitfield could be
		 * deallocated, false if it could not.
		 */
		bool Deallocate(bitfield &pos);

		/** Toggle the value of a bitfield.
		 * @param pos A bitfield to allocate, previously
		 * allocated by dyamicbitmask::Allocate().
		 * @param state The state to set the field to.
		 */
		void Toggle(bitfield &pos, bool state);

		/** Get the value of a bitfield.
		 * @param pos A bitfield to retrieve, previously
		 * allocated by dyamicbitmask::Allocate().
		 * @return The value of the bitfield.
		 * @throw Will throw ModuleException if the bitfield
		 * you provide is outside of the range
		 * 0 >= bitfield.first < size_bits.
		 */
		bool Get(bitfield &pos);

		/** Return the size in bytes allocated to the bits
		 * array.
		 * Note that the actual allocation is twice this,
		 * as there are an equal number of bytes allocated
		 * for the freebits array.
		 */
		unsigned char GetSize();

		virtual unsigned char* GetFreeBits() { return NULL; }

		virtual void SetFreeBits(unsigned char* freebits) { }
	};

	/** The irc_char_traits class is used for RFC-style comparison of strings.
	 * This class is used to implement irc::string, a case-insensitive, RFC-
	 * comparing string class.
	 */
	struct irc_char_traits : std::char_traits<char> {

		/** Check if two chars match
		 */
		static bool eq(char c1st, char c2nd);

		/** Check if two chars do NOT match
		 */
		static bool ne(char c1st, char c2nd);

		/** Check if one char is less than another
		 */
		static bool lt(char c1st, char c2nd);

		/** Compare two strings of size n
		 */
		static int compare(const char* str1, const char* str2, size_t n);

		/** Find a char within a string up to position n
 		 */
		static const char* find(const char* s1, int  n, char c);
	};

	std::string hex(const unsigned char *raw, size_t rawsz);

	/** This typedef declares irc::string based upon irc_char_traits
	 */
	typedef basic_string<char, irc_char_traits, allocator<char> > string;

	const char* Spacify(const char* n);
}

/* Define operators for using >> and << with irc::string to an ostream on an istream. */
/* This was endless fun. No. Really. */
/* It was also the first core change Ommeh made, if anyone cares */
std::ostream& operator<<(std::ostream &os, const irc::string &str);
std::istream& operator>>(std::istream &is, irc::string &str);

/* Define operators for + and == with irc::string to std::string for easy assignment
 * and comparison - Brain
 */
std::string operator+ (std::string& leftval, irc::string& rightval);
irc::string operator+ (irc::string& leftval, std::string& rightval);
bool operator== (const std::string& leftval, const irc::string& rightval);
bool operator== (const irc::string& leftval, const std::string& rightval);

std::string assign(const irc::string &other);
irc::string assign(const std::string &other);

namespace nspace
{
	/** Hashing function to hash irc::string
	 */
	template<> struct hash<irc::string>
	{
		size_t operator()(const irc::string &s) const;
	};
}

#endif