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+// Copyright (C) 2010 Internet Systems Consortium, Inc. ("ISC")
+//
+// Permission to use, copy, modify, and/or distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice appear in all copies.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
+// REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+// AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
+// INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+// LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
+// OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+// PERFORMANCE OF THIS SOFTWARE.
+
+// $Id$
+
+#ifndef __RRTTL_H
+#define __RRTTL_H 1
+
+#include <stdint.h>
+
+#include <exceptions/exceptions.h>
+
+namespace isc {
+namespace dns {
+
+// forward declarations
+class InputBuffer;
+class OutputBuffer;
+class MessageRenderer;
+
+///
+/// \brief A standard DNS module exception that is thrown if an RRTTL object
+/// is being constructed from an unrecognized string.
+///
+class InvalidRRTTL : public Exception {
+public:
+ InvalidRRTTL(const char* file, size_t line, const char* what) :
+ isc::Exception(file, line, what) {}
+};
+
+///
+/// \brief A standard DNS module exception that is thrown if an RRTTL object
+/// is being constructed from a incomplete (too short) wire-format data.
+///
+class IncompleteRRTTL : public Exception {
+public:
+ IncompleteRRTTL(const char* file, size_t line, const char* what) :
+ isc::Exception(file, line, what) {}
+};
+
+///
+/// The \c RRTTL class encapsulates TTLs used in DNS resource records.
+///
+/// This is a straightforward class; an \c RRTTL object simply maintains a
+/// 32-bit unsigned integer corresponding to the TTL value. The main purpose
+/// of this class is to provide convenient interfaces to convert a textual
+/// representation into the integer TTL value and vice versa, and to handle
+/// wire-format representations.
+class RRTTL {
+public:
+ ///
+ /// \name Constructors and Destructor
+ ///
+ /// Note: We use the default copy constructor and the default copy
+ /// assignment operator intentionally.
+ //@{
+ /// Constructor from an integer TTL value.
+ ///
+ /// This constructor never throws an exception.
+ ///
+ /// \param ttlval An 32-bit integer of the RRTTL.
+ explicit RRTTL(uint32_t ttlval) : ttlval_(ttlval) {}
+ /// Constructor from a string.
+ ///
+ /// This version of the implementation only accepts decimal TTL values in
+ /// seconds.
+ /// In a near future version, we'll extend it so that we can accept more
+ /// convenient ones such as "2H" or "1D".
+ ///
+ /// If the given string is not recognized as a valid representation of
+ /// an RR TTL, an exception of class \c InvalidRRTTL will be thrown.
+ ///
+ /// \param ttlstr A string representation of the \c RRTTL
+ explicit RRTTL(const std::string& ttlstr);
+ /// Constructor from wire-format data.
+ ///
+ /// The \c buffer parameter normally stores a complete DNS message
+ /// containing the RRTTL to be constructed. The current read position of
+ /// the buffer points to the head of the type.
+ ///
+ /// If the given data does not large enough to contain a 16-bit integer,
+ /// an exception of class \c IncompleteRRTTL will be thrown.
+ ///
+ /// \param buffer A buffer storing the wire format data.
+ explicit RRTTL(InputBuffer& buffer);
+ ///
+ //@}
+
+ ///
+ /// \name Converter methods
+ ///
+ //@{
+ /// \brief Convert the \c RRTTL to a string.
+ ///
+ /// This version of implementation simply converts the TTL value into the
+ /// numeric textual representation. We may introduce more human-readable
+ /// format depending on the context in future versions.
+ ///
+ /// If resource allocation in rendering process fails, a corresponding
+ /// standard exception will be thrown.
+ ///
+ /// \return A string representation of the \c RRTTL.
+ const std::string toText() const;
+ /// \brief Render the \c RRTTL in the wire format.
+ ///
+ /// This method renders the TTL value in network byte order via \c renderer,
+ /// which encapsulates output buffer and other rendering contexts.
+ ///
+ /// If resource allocation in rendering process fails, a corresponding
+ /// standard exception will be thrown.
+ ///
+ /// \param buffer An output buffer to store the wire data.
+ void toWire(MessageRenderer& renderer) const;
+ /// \brief Render the \c RRTTL in the wire format.
+ ///
+ /// This method renders the TTL value in network byte order into the
+ /// \c buffer.
+ ///
+ /// If resource allocation in rendering process fails, a corresponding
+ /// standard exception will be thrown.
+ ///
+ /// \param renderer DNS message rendering context that encapsulates the
+ /// output buffer in which the RRTTL is to be stored.
+ void toWire(OutputBuffer& buffer) const;
+ //@}
+
+ ///
+ /// \name Getter Methods
+ ///
+ //@{
+ /// \brief Returns the TTL value as a 32-bit unsigned integer.
+ ///
+ /// This method never throws an exception.
+ ///
+ /// \return An 32-bit integer corresponding to the RRTTL.
+ uint32_t getValue() const { return (ttlval_); }
+ //@}
+
+ ///
+ /// \name Comparison methods
+ ///
+ /// Comparison between two \c RRTTL objects is performed in a
+ /// straightforward way, that is, comparing the corresponding TTL values
+ /// (which is the result of the \c getValue() method) as 32-bit unsigned
+ /// integers.
+ //@{
+ /// \brief Return true iff two RRTTLs are equal.
+ ///
+ /// This method never throws an exception.
+ ///
+ /// \param other the \c RRTTL object to compare against.
+ bool equals(const RRTTL& other) const
+ { return (ttlval_ == other.ttlval_); }
+ /// \brief Same as \c equals().
+ bool operator==(const RRTTL& other) const
+ { return (ttlval_ == other.ttlval_); }
+ /// \brief Return true iff two RRTTLs are not equal.
+ ///
+ /// This method never throws an exception.
+ ///
+ /// \param other the \c RRTTL object to compare against.
+ bool nequals(const RRTTL& other) const
+ { return (ttlval_ != other.ttlval_); }
+ /// \brief Same as \c nequals().
+ bool operator!=(const RRTTL& other) const
+ { return (ttlval_ != other.ttlval_); }
+ /// \brief Less-than or equal comparison for RRTTL against \c other.
+ ///
+ /// This method never throws an exception.
+ ///
+ /// \param other the \c RRTTL object to compare against.
+ /// \return true if \c this RRTTL is less than or equal to the \c other;
+ /// otherwise false.
+ bool leq(const RRTTL& other) const
+ { return (ttlval_ <= other.ttlval_); }
+
+ /// Same as \c leq()
+ bool operator<=(const RRTTL& other) const
+ { return (ttlval_ <= other.ttlval_); }
+
+ /// \brief Greater-than or equal comparison for RRTTL against \c other.
+ ///
+ /// This method never throws an exception.
+ ///
+ /// \param other the \c RRTTL object to compare against.
+ /// \return true if \c this RRTTL is greater than or equal to the \c other;
+ /// otherwise false.
+ bool geq(const RRTTL& other) const
+ { return (ttlval_ >= other.ttlval_); }
+
+ /// Same as \c geq()
+ bool operator>=(const RRTTL& other) const
+ { return (ttlval_ >= other.ttlval_); }
+
+ /// \brief Less-than comparison for RRTTL against \c other.
+ ///
+ /// This method never throws an exception.
+ ///
+ /// \param other the \c RRTTL object to compare against.
+ /// \return true if \c this RRTTL is less than the \c other;
+ /// otherwise false.
+ bool lthan(const RRTTL& other) const
+ { return (ttlval_ < other.ttlval_); }
+
+ /// Same as \c lthan()
+ bool operator<(const RRTTL& other) const
+ { return (ttlval_ < other.ttlval_); }
+
+ /// \brief Greater-than comparison for RRTTL against \c other.
+ ///
+ /// This method never throws an exception.
+ ///
+ /// \param other the \c RRTTL object to compare against.
+ /// \return true if \c this RRTTL is greater than the \c other;
+ /// otherwise false.
+ bool gthan(const RRTTL& other) const
+ { return (ttlval_ > other.ttlval_); }
+
+ /// Same as \c gthan()
+ bool operator>(const RRTTL& other) const
+ { return (ttlval_ > other.ttlval_); }
+ //@}
+
+private:
+ uint32_t ttlval_;
+};
+
+///
+/// \brief Insert the \c RRTTL as a string into stream.
+///
+/// This method convert the \c rrttl into a string and inserts it into the
+/// output stream \c os.
+///
+/// This function overloads the global operator<< to behave as described in
+/// ostream::operator<< but applied to \c RRTTL objects.
+///
+/// \param os A \c std::ostream object on which the insertion operation is
+/// performed.
+/// \param rrttl The \c RRTTL object output by the operation.
+/// \return A reference to the same \c std::ostream object referenced by
+/// parameter \c os after the insertion operation.
+std::ostream&
+operator<<(std::ostream& os, const RRTTL& rrttl);
+}
+}
+#endif // __RRTTL_H
+
+// Local Variables:
+// mode: c++
+// End: