Value.h

00001 /*
00002  * Value.h
00003  *
00004  * Created on: Nov 1, 2013
00005  * * Authors: Vincent Wochnik <v.wochnik@gmail.com>
00006  *
00007  * Copyright (c) 2013 Cumulocity GmbH
00008  *
00009  * Permission is hereby granted, free of charge, to any person obtaining
00010  * a copy of this software and associated documentation files (the
00011  * "Software"), to deal in the Software without restriction, including
00012  * without limitation the rights to use, copy, modify, merge, publish,
00013  * distribute, sublicense, and/or sell copies of the Software, and to
00014  * permit persons to whom the Software is furnished to do so, subject to
00015  * the following conditions:
00016  *
00017  * The above copyright notice and this permission notice shall be
00018  * included in all copies or substantial portions of the Software.
00019  *
00020  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
00021  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
00022  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
00023  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
00024  * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
00025  * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
00026  * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
00027  */
00028 
00029 /**
00030  * @file Value.h
00031  * Represents a generic data value.
00032  */
00033 
00034 #ifndef VALUE_H
00035 #define VALUE_H
00036 
00037 #include "config.h"
00038 #include <stddef.h>
00039 #include <stdint.h>
00040 #include "AbstractDataSink.h"
00041 
00042 /** Return value indicating a null value. */
00043 #define VALUE_NULL 0
00044 /** Return value indicating an integer value. */
00045 #define VALUE_INTEGER 1
00046 /** Return value indicating a floating-point number. */
00047 #define VALUE_FLOAT 2
00048 /** Return value indicating a character string. */
00049 #define VALUE_CHARACTER 3
00050 
00051 /**
00052  * A generic value offering means to obtain the value type and contents
00053  * as well as writing the value to a sink.
00054  */
00055 class Value
00056 {
00057     public:
00058         virtual ~Value() { };
00059 
00060         /**
00061          * Returns the value type which can be VALUE_NULL, VALUE_INTEGER,
00062          * VALUE_FLOAT or VALUE_CHARACTER.
00063          * @return the value type
00064          */
00065         virtual uint8_t valueType() const = 0;
00066 
00067         /**
00068          * Returns the integer value if an integer type, otherwise zero.
00069          * @return integer value
00070          */
00071         virtual long integerValue() const = 0;
00072 
00073         /**
00074          * Returns the float value if a float type, otherwise zero.
00075          * @return float value
00076          */
00077         virtual double floatValue() const = 0;
00078 
00079         /**
00080          * Returns the character value if a character type, otherwise zero.
00081          * @return character value
00082          */
00083         virtual const char * characterValue() const = 0;
00084 
00085         /**
00086          * Writes the value to a sink.
00087          * If necessary, quotes and escape characters may be added.
00088          * @param sink the sink to write the value to
00089          * @return the number of bytes written
00090          */
00091         virtual size_t write(AbstractDataSink&) const = 0;
00092 
00093         /**
00094          * Returns the number of bytes required to write this value to a sink.
00095          * @return number of bytes required to write this value
00096          */
00097         virtual size_t length() const = 0;
00098 
00099         /**
00100          * Copies this value to the heap. Referenced contents must also be
00101          * copied.
00102          * @return a new value instance allocated on the heap
00103          */
00104         virtual Value* copy() const = 0;
00105 };
00106 
00107 #endif