Holds a single byte. More...

#include <Byte.h>

Inheritance diagram for libdap::Byte:

Collaboration diagram for libdap::Byte:

Public Types
typedef stack< BaseType * >	btp_stack

Public Member Functions
virtual void	add_var (BaseType *bt, Part part=nil)
	Add a variable.
virtual unsigned int	buf2val (void **val)
	Reads the class data.
	Byte (const string &n)
	The Byte constructor.
	Byte (const string &n, const string &d)
	The Byte server-side constructor.
	Byte (const Byte &copy_from)
virtual bool	check_semantics (string &msg, bool all=false)
	Compare an object's current state with the semantics of its type.
string	dataset () const
	Returns the name of the dataset used to create this instance.
bool	deserialize (UnMarshaller &um, DDS *, bool)
	Deserialize the char on stdin and put the result in `_BUF`.
virtual void	dump (ostream &strm) const
	dumps information about this object
virtual int	element_count (bool leaves=false)
	Count the members of constructor types.
virtual AttrTable &	get_attr_table ()
virtual BaseType *	get_parent ()
virtual bool	is_constructor_type ()
	Returns true if the instance is a constructor (i.e., Structure, Sequence or Grid) type variable.
virtual bool	is_in_selection ()
	Is this variable part of the current selection?
virtual bool	is_simple_type ()
	Returns true if the instance is a numeric, string or URL type variable.
virtual bool	is_vector_type ()
	Returns true if the instance is a vector (i.e., array) type variable.
string	name () const
	Returns the name of the class instance.
Byte &	operator= (const Byte &rhs)
virtual bool	ops (BaseType *b, int op)
	Evaluate relational operators.
virtual void	print_decl (FILE *out, string space=" ", bool print_semi=true, bool constraint_info=false, bool constrained=false)
	Print an ASCII representation of the variable structure.
virtual void	print_decl (ostream &out, string space=" ", bool print_semi=true, bool constraint_info=false, bool constrained=false)
	Print an ASCII representation of the variable structure.
virtual void	print_val (FILE *out, string space="", bool print_decl_p=true)
	Prints the value of the variable.
virtual void	print_val (ostream &out, string space="", bool print_decl_p=true)
	Prints the value of the variable.
virtual void	print_xml (FILE *out, string space=" ", bool constrained=false)
virtual void	print_xml (ostream &out, string space=" ", bool constrained=false)
virtual BaseType *	ptr_duplicate ()
virtual bool	read ()
	Read data into a local buffer.
virtual bool	read_p ()
	Has this variable been read?
virtual bool	send_p ()
	Should this variable be sent?
bool	serialize (ConstraintEvaluator &eval, DDS &dds, Marshaller &m, bool ce_eval)
virtual void	set_attr_table (const AttrTable &at)
virtual void	set_in_selection (bool state)
virtual void	set_name (const string &n)
	Sets the name of the class instance.
virtual void	set_parent (BaseType *parent)
virtual void	set_read_p (bool state)
	Sets the value of the read_p property.
virtual void	set_send_p (bool state)
virtual void	set_synthesized_p (bool state)
void	set_type (const Type &t)
	Sets the type of the class instance.
virtual bool	set_value (const dods_byte value)
virtual bool	synthesized_p ()
virtual string	toString ()
virtual void	transfer_attributes (AttrTable *at)
Type	type () const
	Returns the type of the class instance.
string	type_name () const
	Returns the type of the class instance as a string.
virtual unsigned int	val2buf (void *val, bool reuse=false)
virtual dods_byte	value () const
virtual BaseType *	var (const string &name="", bool exact_match=true, btp_stack *s=0)
	Returns a pointer to a member of a constructor class.
virtual BaseType *	var (const string &name, btp_stack &s)
virtual unsigned int	width ()
	Returns the size of the class instance data.
virtual	~Byte ()
Abstract Methods
virtual void	intern_data (ConstraintEvaluator &eval, DDS &dds)

Protected Member Functions
void	_duplicate (const BaseType &bt)
	Perform a deep copy.

Protected Attributes
dods_byte	_buf

Friends
class	Float32
class	Float64
class	Int16
class	Int32
class	UInt16
class	UInt32

Detailed Description

This class is used to hold eight bits of information. No sign information is implied in its value.

See Also: BaseType

Definition at line 63 of file Byte.h.

Member Typedef Documentation

typedef stack<BaseType *> libdap::BaseType::btp_stack

inherited

Definition at line 214 of file BaseType.h.

Constructor & Destructor Documentation

libdap::Byte::Byte ( const string & n )

The Byte constructor requires only the name of the variable to be created. The name may be omitted, which will create a nameless variable. This may be adequate for some applications.

Parameters

n	A string containing the name of the variable to be created.

Definition at line 79 of file Byte.cc.

Referenced by ptr_duplicate().

libdap::Byte::Byte	(	const string &	n,
		const string &	d
	)

This Byte constructor requires the name of the variable to be created and the name of the dataset from which this variable is being created. This constructor is used in server-side processing, loading structure in from a dataset.

Parameters

n	A string containing the name of the variable to be created.
d	A string containing the name of the dataset from which the variable is being created.

Definition at line 92 of file Byte.cc.

virtual libdap::Byte::~Byte ( )

inlinevirtual

Definition at line 84 of file Byte.h.

libdap::Byte::Byte ( const Byte & copy_from )

Definition at line 95 of file Byte.cc.

References _buf.

Member Function Documentation

void libdap::BaseType::_duplicate ( const BaseType & bt )

protectedinherited

Perform a deep copy. Copies the values of bt into *this. Pointers are dereferenced and their values are copied into a newly allocated instance.

Parameters

bt	The source object.

Definition at line 80 of file BaseType.cc.

References DBG.

Referenced by libdap::BaseType::BaseType(), and libdap::BaseType::operator=().

void libdap::BaseType::add_var	(	BaseType *	bt,
		Part	part = `nil`
	)

virtualinherited

Adds a variable to an instance of a constructor class, such as Array, Structure et cetera. This function is only used by those classes. For constructors with more than one variable, the variables appear in the same order in which they were added (i.e., the order in which add_var() was called). Since this method is only for use by Vectors and Constructors, the BaseType implementation throws InternalErr.

Note: For the implementation of this method in Structure, Sequence, et c., first copy bt and then insert the copy. If bt is itself a constructor type you must either use the var() method to get a pointer to the actual instance added to *this or you must first add all of bt's children to it before adding it to *this. The implementations should use _duplicate() to perform a deep copy of bt.

Todo:: We should get rid of the Part parameter and adopt the convention that the first variable is the Array and all subsequent ones are Maps (when dealing with a Grid, the only time Part matters). This would enable several methods to migrate from Structure, Sequence and Grid to Constructor.

Parameters

bt	The variable to be added to this instance. The caller of this method must free memory it allocates for `v`. This method will make a deep copy of the object pointed to by `v`.
part	The part of the constructor data to be modified. Only meaningful for Grid variables.

See Also: Part

Reimplemented in libdap::Sequence, libdap::Vector, libdap::Array, libdap::Grid, and libdap::Structure.

Definition at line 719 of file BaseType.cc.

Referenced by libdap::DDXParser::ddx_sax2_end_element().

unsigned int libdap::Byte::buf2val ( void ** val )

virtual

Reads the class data into the memory referenced by <i>val</i>.
The caller should either allocate enough storage to <i>val</i>
to hold the class data or set \c *val to null. If <i>*val</i>
is NULL, memory will be allocated by this function with
<tt>new()</tt>. If the memory is allocated this way, the
caller is responsible for deallocating that memory. Array and
values for simple types are stored as C would store an array.

Deprecated:: Use value() in the leaf classes.

@param val A pointer to a pointer to the memory into which the
class data will be copied. If the value pointed to is NULL,
memory will be allocated to hold the data, and the pointer
value modified accordingly. The calling program is responsible
for deallocating the memory references by this pointer.

@return The size (in bytes) of the information copied to <i>val</i>.

Implements libdap::BaseType.

Definition at line 181 of file Byte.cc.

References _buf, and width().

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bool libdap::BaseType::check_semantics	(	string &	msg,
		bool	all = `false`
	)

virtualinherited

This function checks the class instance for internal consistency. This is important to check for complex constructor classes. For BaseType, an object is semantically correct if it has both a non-null name and type.

For example, an Int32 instance would return FALSE if it had no name or no type defined. A Grid instance might return FALSE for more complex reasons, such as having Map arrays of the wrong size or shape.

This function is used by the DDS class, and will rarely, if ever, be explicitly called by a DODS application program. A variable must pass this test before it is sent, but there may be many other stages in a retrieve operation where it would fail.

Returns: Returns FALSE when the current state violates some aspect of the type semantics, TRUE otherwise.

Parameters

msg	A returned string, containing a message indicating the source of any problem.
all	For complex constructor types (Grid, Sequence, Structure), this flag indicates whether to check the semantics of the member variables, too.

See Also: DDS::check_semantics

Reimplemented in libdap::Sequence, libdap::Array, libdap::Grid, libdap::Vector, and libdap::Structure.

Definition at line 1036 of file BaseType.cc.

References libdap::dods_null_c.

Referenced by libdap::Structure::check_semantics(), libdap::Grid::check_semantics(), and libdap::Sequence::check_semantics().

string libdap::BaseType::dataset ( ) const

inherited

A dataset from which the data is to be read. The meaning of this string will vary among different types of data sources. It may be the name of a data file or an identifier used to read data from a relational database.

Definition at line 231 of file BaseType.cc.

Referenced by libdap::Sequence::read_row(), libdap::Str::serialize(), libdap::UInt16::serialize(), libdap::Int16::serialize(), libdap::Float32::serialize(), libdap::UInt32::serialize(), libdap::Float64::serialize(), libdap::Int32::serialize(), serialize(), libdap::Vector::serialize(), libdap::Structure::serialize(), and libdap::Grid::serialize().

bool libdap::Byte::deserialize	(	UnMarshaller &	um,
		DDS *	,
		bool
	)

virtual

Implements libdap::BaseType.

Definition at line 155 of file Byte.cc.

References _buf, and libdap::UnMarshaller::get_byte().

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void libdap::Byte::dump ( ostream & strm ) const

virtual

Displays the pointer value of this instance and information about this instance.

Parameters

strm	C++ i/o stream to dump the information to

Returns: void

Reimplemented from libdap::BaseType.

Definition at line 296 of file Byte.cc.

References _buf, libdap::DapIndent::Indent(), libdap::DapIndent::LMarg(), and libdap::DapIndent::UnIndent().

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int libdap::BaseType::element_count ( bool leaves = false )

virtualinherited

Return a count of the total number of variables in this variable. This is used to count the number of variables held by a constructor variable - for simple type and vector variables it always returns 1.

For compound data types, there are two ways to count members. You can count the members, or you can count the simple members and add that to the count of the compound members. For example, if a Structure contains an Int32 and another Structure that itself contains two Int32 members, the element count of the top-level structure could be two (one Int32 and one Structure) or three (one Int32 by itself and two Int32's in the subsidiary Structure). Use the leaves parameter to control which kind of counting you desire.

Returns: Returns 1 for simple types. For compound members, the count depends on the leaves argument.

Parameters

leaves This parameter is only relevant if the object contains other compound data types. If FALSE, the function counts only the data variables mentioned in the object's declaration. If TRUE, it counts the simple members, and adds that to the sum of the counts for the compound members. This parameter has no effect for simple type variables.

Reimplemented in libdap::Sequence, libdap::Grid, libdap::Structure, and libdap::Vector.

Definition at line 407 of file BaseType.cc.

Referenced by libdap::Vector::element_count().

AttrTable & libdap::BaseType::get_attr_table ( )

virtualinherited

Get this variable's AttrTable. It's generally a bad idea to return a reference to a contained object, but in this case it seems that building an interface inside BaseType is overkill.

Use the AttrTable methods to manipulate the table.

Definition at line 531 of file BaseType.cc.

Referenced by libdap::Constructor::print_xml(), libdap::Grid::print_xml(), libdap::BaseType::print_xml(), libdap::Array::print_xml_core(), libdap::Constructor::transfer_attributes(), libdap::Grid::transfer_attributes(), and libdap::BaseType::transfer_attributes().

BaseType * libdap::BaseType::get_parent ( )

virtualinherited

Return a pointer to the Constructor or Vector which holds (contains) this variable. If this variable is at the top level, this method returns null.

Returns: A BaseType pointer to the variable's parent.

Definition at line 655 of file BaseType.cc.

Referenced by libdap::function_linear_scale(), libdap::Sequence::intern_data_for_leaf(), libdap::Sequence::intern_data_parent_part_two(), libdap::Sequence::serialize_leaf(), and libdap::Sequence::serialize_parent_part_two().

void libdap::BaseType::intern_data	(	ConstraintEvaluator &	eval,
		DDS &	dds
	)

virtualinherited

Similar to using serialize() and deserialize() together in one object. Data are read as for serialize and those values are stored in the objects as deserialize() does but does not write and then read data to/from a stream.

This method is defined by the various data type classes. It calls the read() abstract method.

Parameters

eval	Use this as the constraint expression evaluator.
dds	The Data Descriptor Structure object corresponding to this dataset. See The DODS User Manual for information about this structure.

Reimplemented in libdap::Sequence, libdap::Grid, libdap::Structure, and libdap::Vector.

Definition at line 799 of file BaseType.cc.

References DBG, libdap::BaseType::name(), libdap::BaseType::read(), libdap::BaseType::read_p(), libdap::DDS::timeout_off(), and libdap::DDS::timeout_on().

Referenced by libdap::Grid::intern_data().

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bool libdap::BaseType::is_constructor_type ( )

virtualinherited

Returns: True if the instance is a Structure, Sequence or Grid, False otherwise.

Definition at line 356 of file BaseType.cc.

References libdap::dods_array_c, libdap::dods_byte_c, libdap::dods_float32_c, libdap::dods_float64_c, libdap::dods_grid_c, libdap::dods_int16_c, libdap::dods_int32_c, libdap::dods_null_c, libdap::dods_sequence_c, libdap::dods_str_c, libdap::dods_structure_c, libdap::dods_uint16_c, libdap::dods_uint32_c, libdap::dods_url_c, and libdap::BaseType::type().

Referenced by libdap::DDXParser::ddx_sax2_end_element(), libdap::DDS::leaf_match(), and libdap::Vector::var().

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bool libdap::BaseType::is_in_selection ( )

virtualinherited

Does this variable appear in either the selection part or as a function argument in the current constrain expression. If this property is set (true) then implementations of the read() method should read this variable.

Note: This method does not check, nor does it know about the semantics of, string arguments passed to functions. Those functions might include variable names in strings; they are responsible for reading those variables. See the grid (func_grid_select()) for an example.

See Also: BaseType::read()

Definition at line 610 of file BaseType.cc.

bool libdap::BaseType::is_simple_type ( )

virtualinherited

Returns: True if the instance is a scalar numeric, String or URL variable, False otherwise. Arrays (even of simple types) return False.

See Also: is_vector_type()

Definition at line 295 of file BaseType.cc.

References libdap::dods_array_c, libdap::dods_byte_c, libdap::dods_float32_c, libdap::dods_float64_c, libdap::dods_grid_c, libdap::dods_int16_c, libdap::dods_int32_c, libdap::dods_null_c, libdap::dods_sequence_c, libdap::dods_str_c, libdap::dods_structure_c, libdap::dods_uint16_c, libdap::dods_uint32_c, libdap::dods_url_c, and libdap::BaseType::type().

Referenced by libdap::Grid::check_semantics(), libdap::extract_double_array(), libdap::extract_double_value(), and libdap::set_array_using_double().

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bool libdap::BaseType::is_vector_type ( )

virtualinherited

Returns: True if the instance is an Array, False otherwise.

Definition at line 324 of file BaseType.cc.

References libdap::dods_array_c, libdap::dods_byte_c, libdap::dods_float32_c, libdap::dods_float64_c, libdap::dods_grid_c, libdap::dods_int16_c, libdap::dods_int32_c, libdap::dods_null_c, libdap::dods_sequence_c, libdap::dods_str_c, libdap::dods_structure_c, libdap::dods_uint16_c, libdap::dods_uint32_c, libdap::dods_url_c, and libdap::BaseType::type().

Referenced by libdap::DDXParser::ddx_sax2_end_element(), and libdap::DDS::leaf_match().

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string libdap::BaseType::name ( ) const

inherited

Definition at line 210 of file BaseType.cc.

Byte & libdap::Byte::operator= ( const Byte & rhs )

Definition at line 105 of file Byte.cc.

References _buf.

bool libdap::Byte::ops	(	BaseType *	b,
		int	op
	)

virtual

This method contains the relational operators used by the constraint expression evaluator in the DDS class. Each class that wants to be able to evaluate relational expressions must overload this function. The implementation in BaseType throws an InternalErr exception. The DAP library classes Byte, ..., Url provide specializations of this method. It is not meaningful for classes such as Array because relational expressions using Array are not supported.

The op argument refers to a table generated by bison from the constraint expression parser. Use statements like the following to correctly interpret its value:

switch (op) {
    case EQUAL: return i1 == i2;
    case NOT_EQUAL: return i1 != i2;
    case GREATER: return i1 > i2;
    case GREATER_EQL: return i1 >= i2;
    case LESS: return i1 < i2;
    case LESS_EQL: return i1 <= i2;
    case REGEXP: throw Error("Regular expressions are not supported for integer values");
    default: throw Error("Unknown operator");
}

This function is used by the constraint expression evaluator.

Parameters

b	Compare the value of this instance with b.
op	An integer index indicating which relational operator is implied. Choose one from the following: `EQUAL`, `NOT_EQUAL`, `GREATER`, `GREATER_EQL`, `LESS`, `LESS_EQL`, and `REGEXP`.

Returns: The boolean value of the comparison.

Reimplemented from libdap::BaseType.

Definition at line 237 of file Byte.cc.

References _buf, libdap::dods_byte_c, libdap::dods_float32_c, libdap::dods_float64_c, libdap::dods_int16_c, libdap::dods_int32_c, libdap::dods_uint16_c, libdap::dods_uint32_c, libdap::BaseType::read(), libdap::BaseType::read_p(), libdap::rops(), and libdap::BaseType::type().

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void libdap::BaseType::print_decl	(	FILE *	out,
		string	space = `" "`,
		bool	print_semi = `true`,
		bool	constraint_info = `false`,
		bool	constrained = `false`
	)

virtualinherited

Write the variable's declaration in a C-style syntax. This function is used to create textual representation of the Data Descriptor Structure (DDS). See The DODS User Manual for information about this structure.

A simple array declaration might look like this:

Float64 lat[lat = 180];

While a more complex declaration (for a Grid, in this case), would look like this:

Grid {
ARRAY:
Int32 sst[time = 404][lat = 180][lon = 360];
MAPS:
Float64 time[time = 404];
Float64 lat[lat = 180];
Float64 lon[lon = 360];
} sst;

Parameters

out	The output stream on which to print the declaration.
space	Each line of the declaration will begin with the characters in this string. Usually used for leading spaces.
print_semi	A boolean value indicating whether to print a semicolon at the end of the declaration.
constraint_info	A boolean value indicating whether constraint information is to be printed with the declaration. If the value of this parameter is TRUE, `print_decl()` prints the value of the variable's `send_p()` flag after the declaration.
constrained	If this boolean value is TRUE, the variable's declaration is only printed if is the `send_p()` flag is TRUE. If a constraint expression is in place, and this variable is not requested, the `send_p()` flag is FALSE.

See Also: DDS; DDS::CE

Reimplemented in libdap::Array, libdap::Grid, and libdap::Constructor.

Definition at line 853 of file BaseType.cc.

References libdap::id2www(), libdap::BaseType::send_p(), and libdap::BaseType::type_name().

Referenced by libdap::DODSFilter::functional_constraint(), libdap::Grid::print_decl(), libdap::Array::print_decl(), libdap::Str::print_val(), libdap::UInt16::print_val(), libdap::Int16::print_val(), libdap::Float32::print_val(), libdap::UInt32::print_val(), libdap::Float64::print_val(), libdap::Int32::print_val(), and print_val().

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void libdap::BaseType::print_decl	(	ostream &	out,
		string	space = `" "`,
		bool	print_semi = `true`,
		bool	constraint_info = `false`,
		bool	constrained = `false`
	)

virtualinherited

Write the variable's declaration in a C-style syntax. This function is used to create textual representation of the Data Descriptor Structure (DDS). See The DODS User Manual for information about this structure.

A simple array declaration might look like this:

Float64 lat[lat = 180];

While a more complex declaration (for a Grid, in this case), would look like this:

Grid {
ARRAY:
Int32 sst[time = 404][lat = 180][lon = 360];
MAPS:
Float64 time[time = 404];
Float64 lat[lat = 180];
Float64 lon[lon = 360];
} sst;

Parameters

out	The output stream on which to print the declaration.
space	Each line of the declaration will begin with the characters in this string. Usually used for leading spaces.
print_semi	A boolean value indicating whether to print a semicolon at the end of the declaration.
constraint_info	A boolean value indicating whether constraint information is to be printed with the declaration. If the value of this parameter is TRUE, `print_decl()` prints the value of the variable's `send_p()` flag after the declaration.
constrained	If this boolean value is TRUE, the variable's declaration is only printed if is the `send_p()` flag is TRUE. If a constraint expression is in place, and this variable is not requested, the `send_p()` flag is FALSE.

See Also: DDS; DDS::CE

Reimplemented in libdap::Array, libdap::Grid, and libdap::Constructor.

Definition at line 919 of file BaseType.cc.

References libdap::id2www(), libdap::BaseType::send_p(), and libdap::BaseType::type_name().

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void libdap::Byte::print_val	(	FILE *	out,
		string	space = `""`,
		bool	print_decl_p = `true`
	)

virtual

Prints the value of the variable, with its declaration. This function is primarily intended for debugging DODS applications. However, it can be overloaded and used to do some useful things. Take a look at the asciival and writeval clients, both of which overload this to output the values of variables in different ways.

Parameters

out	The output stream on which to print the value.
space	This value is passed to the print_decl() function, and controls the leading spaces of the output.
print_decl_p	A boolean value controlling whether the variable declaration is printed as well as the value.

Implements libdap::BaseType.

Definition at line 216 of file Byte.cc.

References _buf, and libdap::BaseType::print_decl().

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void libdap::Byte::print_val	(	ostream &	out,
		string	space = `""`,
		bool	print_decl_p = `true`
	)

virtual

Prints the value of the variable, with its declaration. This function is primarily intended for debugging DODS applications. However, it can be overloaded and used to do some useful things. Take a look at the asciival and writeval clients, both of which overload this to output the values of variables in different ways.

Parameters

out	The output ostream on which to print the value.
space	This value is passed to the print_decl() function, and controls the leading spaces of the output.
print_decl_p	A boolean value controlling whether the variable declaration is printed as well as the value.

Implements libdap::BaseType.

Definition at line 227 of file Byte.cc.

References _buf, and libdap::BaseType::print_decl().

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void libdap::BaseType::print_xml	(	FILE *	out,
		string	space = `" "`,
		bool	constrained = `false`
	)

virtualinherited

Write the XML representation of this variable. This method is used to build the DDX XML response.

Parameters

out	Destination.
space	Use this to indent child declarations. Default is "".
constrained	If true, only print this if it's part part of the current projection. Default is False.

Reimplemented in libdap::Array, libdap::Grid, and libdap::Constructor.

Definition at line 948 of file BaseType.cc.

References libdap::BaseType::get_attr_table(), libdap::AttrTable::get_size(), libdap::id2xml(), libdap::AttrTable::print_xml(), libdap::BaseType::send_p(), and libdap::BaseType::type_name().

Referenced by libdap::Array::print_xml_core().

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void libdap::BaseType::print_xml	(	ostream &	out,
		string	space = `" "`,
		bool	constrained = `false`
	)

virtualinherited

Write the XML representation of this variable. This method is used to build the DDX XML response.

Parameters

out	Destination output stream
space	Use this to indent child declarations. Default is "".
constrained	If true, only print this if it's part part of the current projection. Default is False.

Reimplemented in libdap::Array, libdap::Grid, and libdap::Constructor.

Definition at line 976 of file BaseType.cc.

References libdap::BaseType::get_attr_table(), libdap::AttrTable::get_size(), libdap::id2xml(), libdap::AttrTable::print_xml(), libdap::BaseType::send_p(), and libdap::BaseType::type_name().

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BaseType * libdap::Byte::ptr_duplicate ( )

virtual

Clone this instance. Allocate a new instance and copy *this into it. This method must perform a deep copy.

Note: This method should not copy data values, but must copy all other fields in the object.

Returns: A newly allocated copy of this.

Implements libdap::BaseType.

Definition at line 100 of file Byte.cc.

References Byte().

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bool libdap::BaseType::read ( )

virtualinherited

This method should be implemented for each of the data type classes (Byte, ..., Grid) when using the DAP class library to build a server. This method is only for DAP servers. The library provides a default definition here which throws an InternalErr exception unless the read_p property has been set. In that case it returns false, indicating that all the data have been read. The latter case can happen when building a constant value that needs to be passed to a function. The variable/constant is loaded with a value when it is created.

When implementing a new DAP server, the Byte, ..., Grid data type classes are usually specialized. In each of those specializations read() should be defined to read values from the data source and store them in the object's local buffer. The read() method is called by other methods in this library. When writing read(), follow these rules:

read() should throw Error if it encounters an error. The message should be verbose enough to be understood by someone running a client on a different machine.
The value(s) should be read if and only if either send_p() or is_in_selection() return true. If neither of these return true, the value(s) should not be read. This is important when writing read() for a Constructor type such as Grid where a client may ask for only the map vectors (and thus reading the much larger Array part is not needed).
For each specialization of read(), the method should first test the value of the read_p property (using the read_p() method) and read values only if the value of read_p() is false. Once the read() method reads data and stores it in the instance, it must set the value of the read_p property to true using set_read_p(). If your read() methods fail to do this data may not serialize correctly.
The Array::read() and Grid::read() methods should take into account any restrictions on Array sizes.
If you are writing Sequence::read(), be sure to check the documentation for Sequence::read_row() and Sequence::serialize() so you understand how Sequence::read() is being called.
For Sequence::read(), your specialization must correctly manage the unsent_data property and row count in addition to the read_p property (handle the read_p property as describe above). For a Sequence to serialize correctly, once all data from the Sequence has been read, unsent_data property must be set to false (use Sequence::set_unsent_data()). Also, at that time the row number counter must be reset (use Sequence::reset_row_counter()). Typically the correct time to set unsent_data to false and reset the row counter is the time when Sequence::read() return false indicating that all the data for the Sequence have been read. Failure to handle these tasks will break serialization of nested Sequences. Note that when Sequence::read() returns with a result of true (indicating there is more data to send, the value of the unsent_data property should be true.

Also, if you server must handle nested sequences, be sure to read about subclassing set_read_p().

Returns: The return value of this method for all types except Sequence should always be false. Sequences should return true to indicate more values remain in the Sequence, false to indicate no more values remain. (see Sequence::serialize() and Sequence::read_row()).

See Also: BaseType; Sequence

Reimplemented in libdap::Structure.

Definition at line 790 of file BaseType.cc.

Referenced by libdap::GridGeoConstraint::apply_constraint_to_data(), libdap::ArrayGeoConstraint::apply_constraint_to_data(), libdap::GeoConstraint::flip_latitude_within_array(), libdap::function_geogrid(), libdap::function_grid(), libdap::function_linear_scale(), libdap::Vector::intern_data(), libdap::Grid::intern_data(), libdap::BaseType::intern_data(), libdap::Str::ops(), libdap::Int16::ops(), libdap::UInt16::ops(), libdap::Float32::ops(), libdap::UInt32::ops(), libdap::Int32::ops(), libdap::Float64::ops(), ops(), libdap::Sequence::read_row(), libdap::GeoConstraint::reorder_data_longitude_axis(), libdap::Str::serialize(), libdap::UInt16::serialize(), libdap::Int16::serialize(), libdap::Float32::serialize(), libdap::UInt32::serialize(), libdap::Int32::serialize(), libdap::Float64::serialize(), serialize(), libdap::Vector::serialize(), and libdap::Grid::serialize().

bool libdap::BaseType::read_p ( )

virtualinherited

Returns true if the value(s) for this variable have been read from the data source, otherwise returns false. This method is used to determine when values need to be read using the read() method. When read_p() returns true, this library assumes that buf2val() (and other methods such as get_vec()) can be used to access the value(s) of a variable.

Returns: True if the variable's value(s) have been read, false otherwise.

Definition at line 444 of file BaseType.cc.

Referenced by libdap::extract_double_array(), libdap::extract_double_value(), libdap::extract_string_argument(), libdap::Vector::intern_data(), libdap::Structure::intern_data(), libdap::Grid::intern_data(), libdap::BaseType::intern_data(), libdap::Str::ops(), libdap::UInt16::ops(), libdap::Int16::ops(), libdap::Float32::ops(), libdap::UInt32::ops(), libdap::Int32::ops(), libdap::Float64::ops(), ops(), libdap::Structure::read(), libdap::Sequence::read_row(), libdap::Str::serialize(), libdap::UInt16::serialize(), libdap::Int16::serialize(), libdap::Float32::serialize(), libdap::UInt32::serialize(), libdap::Int32::serialize(), libdap::Float64::serialize(), serialize(), libdap::Vector::serialize(), libdap::Structure::serialize(), libdap::Grid::serialize(), and libdap::Vector::set_value_slice_from_row_major_vector().

bool libdap::BaseType::send_p ( )

virtualinherited

Returns the state of the send_p property. If true, this variable should be sent to the client, if false, it should not. If no constraint expression (CE) has been evaluated, this property is true for all variables in a data source (i.e., for all the variables listed in a DDS). If a CE has been evaluated, this property is true only for those variables listed in the projection part of the CE.

Returns: True if the variable should be sent to the client, false otherwise.

Definition at line 503 of file BaseType.cc.

Referenced by libdap::Grid::components(), libdap::Grid::intern_data(), libdap::Constructor::print_decl(), libdap::Grid::print_decl(), libdap::Array::print_decl(), libdap::BaseType::print_decl(), libdap::Grid::print_val(), libdap::Constructor::print_xml(), libdap::Grid::print_xml(), libdap::BaseType::print_xml(), libdap::Array::print_xml_core(), libdap::Grid::projection_yields_grid(), and libdap::Grid::serialize().

bool libdap::Byte::serialize	(	ConstraintEvaluator &	eval,
		DDS &	dds,
		Marshaller &	m,
		bool	ce_eval
	)

virtual

Serialize the contents of member _BUF (the object's internal buffer, used to hold data) and write the result to stdout. If FLUSH is true, write the contents of the output buffer to the kernel. FLUSH is false by default. If CE_EVAL is true, evaluate the current constraint expression; only send data if the CE evaluates to true.

Returns: False if a failure to read, send or flush is detected, true otherwise.

Implements libdap::BaseType.

Definition at line 132 of file Byte.cc.

References _buf, libdap::BaseType::dataset(), libdap::ConstraintEvaluator::eval_selection(), libdap::Marshaller::put_byte(), libdap::BaseType::read(), libdap::BaseType::read_p(), libdap::DDS::timeout_off(), and libdap::DDS::timeout_on().

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void libdap::BaseType::set_attr_table ( const AttrTable & at )

virtualinherited

Set this variable's attribute table.

Parameters

at	Source of the attributes.

Definition at line 539 of file BaseType.cc.

void libdap::BaseType::set_in_selection ( bool state )

virtualinherited

Set the in_selection property to state. This property indicates that the variable is used as a parameter to a constraint expression function or that it appears as an argument in a selection sub-expression. If set (true), implementations of the BaseType::read() method should read this variable.

Parameters

state Set the in_selection property to this state.

See Also: BaseType::read(); BaseType::is_in_selection() for more information.

Reimplemented in libdap::Sequence, libdap::Grid, and libdap::Structure.

Definition at line 625 of file BaseType.cc.

Referenced by libdap::Grid::set_in_selection().

void libdap::BaseType::set_name ( const string & n )

virtualinherited

Definition at line 217 of file BaseType.cc.

References libdap::BaseType::name(), and libdap::www2id().

Referenced by libdap::Vector::add_var(), libdap::Array::print_xml_core(), and libdap::Vector::set_name().

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void libdap::BaseType::set_parent ( BaseType * parent )

virtualinherited

Set the parent property for this variable. Only instances of Constructor or Vector should call this method.

Parameters

parent Pointer to the Constructor of Vector parent variable.

Exceptions

InternalErr thrown if called with anything other than a Constructor or Vector.

Definition at line 638 of file BaseType.cc.

Referenced by libdap::Vector::_duplicate(), libdap::Structure::_duplicate(), libdap::Grid::_duplicate(), libdap::Grid::add_map(), libdap::Structure::add_var(), libdap::Grid::add_var(), libdap::Vector::add_var(), libdap::Sequence::add_var(), libdap::Grid::prepend_map(), libdap::Grid::set_array(), and libdap::Vector::Vector().

void libdap::BaseType::set_read_p ( bool state )

virtualinherited

Sets the value of the read_p property. This indicates that the value(s) of this variable has/have been read. An implementation of the read() method would typically use this to set the read_p property to true.

Note: For most of the types the default implementation of this method is fine. However, if you're building a server which must handle data represented using nested sequences, then you may need to provide a specialization of Sequence::set_read_p(). By default Sequence::set_read_() recursively sets the read_p property for all child variables to state. For servers where one Sequence reads an outer set of values and another reads an inner set, this is cumbersome. In such a case, it is easier to specialize Sequence::set_read_p() so that it does not recursively set the read_p property for the inner Sequence. Be sure to see the documentation for the read() method!; For synthesized variables, this method does nothing. Thus, if a synthesized variable is added to a Sequence, the Sequence can iteratively reset the read_p property without affecting the value of that property for the synthesized variable. That's important since a synthesized variable's value is calculated, not read.

Todo:: Look at making synthesized variables easier to implement and at making them more integrated into the overall CE evaluation process. Maybe the code that computes the synthesized var's value should be in the that variable's read() method? This might provide a way to get rid of the awkward 'projection functions' by replacing them with real children of BaseType. It would also provide a way to clean up the way the synthesized_p prop intrudes on the read_p prop.

See Also: BaseType::read()

Parameters

state Set the read_p property to this state.

Reimplemented in libdap::Sequence, libdap::Grid, libdap::Structure, and libdap::Vector.

Definition at line 483 of file BaseType.cc.

References DBG, and libdap::BaseType::name().

Referenced by libdap::Vector::set_read_p(), libdap::Grid::set_read_p(), libdap::Str::set_value(), libdap::UInt16::set_value(), libdap::Int16::set_value(), libdap::Float32::set_value(), libdap::Int32::set_value(), libdap::UInt32::set_value(), libdap::Float64::set_value(), and set_value().

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void libdap::BaseType::set_send_p ( bool state )

virtualinherited

Sets the value of the send_p flag. This function is meant to be called from within the constraint evaluator of other code which determines that this variable should be returned to the client. Data are ready to be sent when both the _send_p and _read_p flags are set to TRUE.

Parameters

state The logical state to set the send_p flag.

Reimplemented in libdap::Sequence, libdap::Grid, libdap::Structure, and libdap::Vector.

Definition at line 517 of file BaseType.cc.

References DBG, and libdap::BaseType::name().

Referenced by libdap::ConstraintEvaluator::eval_function_clauses(), libdap::DDS::mark(), libdap::DODSFilter::send_data_ddx(), libdap::Vector::set_send_p(), and libdap::Grid::set_send_p().

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void libdap::BaseType::set_synthesized_p ( bool state )

virtualinherited

Set the synthesized flag. Before setting this flag be sure to set the read_p() state. Once this flag is set you cannot alter the state of the read_p flag!

See Also: synthesized_p()

Definition at line 427 of file BaseType.cc.

void libdap::BaseType::set_type ( const Type & t )

inherited

Definition at line 245 of file BaseType.cc.

Referenced by libdap::Url::Url().

bool libdap::Byte::set_value ( const dods_byte value )

virtual

Set the value of this instance.

Parameters

value The value

Returns: Always returns true; the return type of bool is for compatibility with the Passive* subclasses written by HAO.

Definition at line 200 of file Byte.cc.

References _buf, libdap::BaseType::set_read_p(), and value().

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bool libdap::BaseType::synthesized_p ( )

virtualinherited

Returns true if the variable is a synthesized variable. A synthesized variable is one that is added to the dataset by the server (usually with a `projection function'.

Definition at line 416 of file BaseType.cc.

string libdap::BaseType::toString ( )

virtualinherited

Write out the object's internal fields in a string. To be used for debugging when regular inspection w/ddd or gdb isn't enough.

Returns: A string which shows the object's internal stuff.

Reimplemented in libdap::Sequence.

Definition at line 161 of file BaseType.cc.

References libdap::BaseType::type_name().

Referenced by libdap::GSEClause::GSEClause().

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void libdap::BaseType::transfer_attributes ( AttrTable * at_container )

virtualinherited

Transfer attributes from a DAS object into this variable. Because of the rough history of the DAS object and the way that various server code built the DAS, this is necessarily a heuristic process. The intent is that this method will be overridden by handlers that need to look for certain patterns in the DAS (e.g., hdf4's odd variable_dim_n; where n = 0, 1, 2, ...) attribute containers.

There should be a one-to-one mapping between variables and attribute containers. However, in some cases one variable has attributes spread across several top level containers and in some cases one container is used by several variables

Note: This method is technically unnecessary because a server (or client) can easily add attributes directly using the DDS::get_attr_table or BaseType::get_attr_table methods and then poke values in using any of the methods AttrTable provides. This method exists to ease the transition to DDS objects which contain attribute information for the existing servers (Since they all make DAS objects separately from the DDS). They could be modified to use the same AttrTable methods but operate on the AttrTable instances in a DDS/BaseType instead of those in a DAS.

Parameters

at_container Transfer attributes from this container.

Returns: void

Reimplemented in libdap::Grid, and libdap::Constructor.

Definition at line 571 of file BaseType.cc.

References libdap::AttrTable::append_attr(), libdap::AttrTable::append_container(), libdap::AttrTable::attr_begin(), libdap::Attr_container, libdap::AttrTable::attr_end(), DBG, libdap::BaseType::get_attr_table(), libdap::AttrTable::get_attr_table(), libdap::AttrTable::get_attr_type(), libdap::AttrTable::get_attr_vector(), libdap::AttrTable::get_name(), libdap::AttrTable::get_type(), libdap::BaseType::name(), and libdap::AttrTable::set_is_global_attribute().

Referenced by libdap::Grid::transfer_attributes().

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Type libdap::BaseType::type ( ) const

inherited

Definition at line 238 of file BaseType.cc.

Referenced by libdap::Array::add_var(), libdap::Vector::buf2val(), libdap::Grid::check_semantics(), libdap::Vector::deserialize(), libdap::Vector::dump(), libdap::extract_double_array(), libdap::extract_double_value(), libdap::extract_string_argument(), libdap::function_linear_scale(), libdap::XDRFileUnMarshaller::get_vector(), libdap::XDRStreamUnMarshaller::get_vector(), libdap::Vector::intern_data(), libdap::Sequence::intern_data_for_leaf(), libdap::Sequence::intern_data_parent_part_two(), libdap::Vector::is_cardinal_type(), libdap::BaseType::is_constructor_type(), libdap::BaseType::is_simple_type(), libdap::BaseType::is_vector_type(), libdap::Str::ops(), libdap::UInt16::ops(), libdap::Int16::ops(), libdap::Float32::ops(), libdap::UInt32::ops(), libdap::Float64::ops(), libdap::Int32::ops(), ops(), libdap::Sequence::print_one_row(), libdap::XDRFileMarshaller::put_vector(), libdap::XDRStreamMarshaller::put_vector(), libdap::Vector::reserve_value_capacity(), libdap::Vector::serialize(), libdap::Sequence::serialize_leaf(), libdap::Sequence::serialize_parent_part_two(), libdap::set_array_using_double(), libdap::Vector::set_value(), libdap::Vector::set_value_slice_from_row_major_vector(), libdap::Vector::set_vec(), libdap::Vector::val2buf(), libdap::Vector::value(), and libdap::Vector::var().

string libdap::BaseType::type_name ( ) const

inherited

unsigned int libdap::Byte::val2buf	(	void *	val,
		bool	reuse = `false`
	)

virtual

Store the value referenced by val in the object's internal buffer. reuse has no effect because this class does not dynamically allocate storage for the internal buffer.

Returns: The size (in bytes) of the value's representation.

Implements libdap::BaseType.

Definition at line 167 of file Byte.cc.

References _buf, and width().

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dods_byte libdap::Byte::value ( ) const

virtual

Get the value of this instance.

Returns: The value.

Definition at line 210 of file Byte.cc.

References _buf.

Referenced by libdap::extract_double_value(), and set_value().

BaseType * libdap::BaseType::var	(	const string &	name = `""`,
		bool	exact_match = `true`,
		btp_stack *	s = `0`
	)

virtualinherited

Returns a pointer to the contained variable in a composite class. The composite classes are those made up of aggregated simple data types. Array, Grid, and Structure are composite types, while Int and Float are simple types. This function is only used by composite classes. The BaseType implementation always returns null.

Several of the subclasses provide alternate access methods that make sense for that particular data type. For example, the Array class defines a *var(int i) method that returns the ith entry in the Array data, and the Structure provides a *var(Vars_iter) function using a pseudo-index to access the different members of the structure.

Parameters

name	The name of the class member. Defaults to ""
exact_match	True if only interested in variables whose full names match n exactly. If false, returns the first variable whose name matches name. For example, if name is `x` and `point.x` is a variable, then var("x", false) would return a BaseType pointer to `point.x`. If exact_match was `true` then name would need to be `"point.x"` for var to return that pointer. This feature simplifies constraint expressions for datasets which have complex, nested, constructor variables. Defaults to true.
s	Record the path to name. Defaults to null, in which case it is not used.

Returns: A pointer to the member named in the n argument. If no name is given, the function returns the first (only) variable. For example, an Array has only one variable, while a Structure can have many.

Reimplemented in libdap::Sequence, libdap::Vector, libdap::Grid, and libdap::Structure.

Definition at line 662 of file BaseType.cc.

Referenced by libdap::DDS::exact_match(), libdap::DDS::leaf_match(), libdap::Constructor::transfer_attributes(), and libdap::Vector::var().

BaseType * libdap::BaseType::var	(	const string &	name,
		btp_stack &	s
	)

virtualinherited

This version of var(...) searches for name and returns a pointer to the BaseType object if found. It uses the same search algorithm as BaseType::var(const string &, bool, btp_stack *) when exact_match is false. In addition to returning a pointer to the variable, it pushes onto s a BaseType pointer to each constructor type that ultimately contains name.

Note: The BaseType implementation always returns null. There are no default values for the parameters. If var() is called w/o any params, the three parameter version will be used.

Deprecated:: This method is deprecated because it tries first to use exact_match and, if that fails, then tries leaf_match. It's better to use the alternate form of var(...) and specify exactly what you'd like to do.

Returns: A pointer to the named variable.

Reimplemented in libdap::Sequence, libdap::Vector, libdap::Grid, and libdap::Structure.

Definition at line 684 of file BaseType.cc.

unsigned int libdap::Byte::width ( )

virtual

Return the number of bytes that are required to hold the instance's value. In the case of simple types such as Int32, this is the size of one Int32 (four bytes). For a String or Url type, width() returns the number of bytes needed for a String * variable, not the bytes needed for all the characters, since that value cannot be determined from type information alone. For Structure, and other constructor types size() returns the number of bytes needed to store pointers to the C++ objects.

Implements libdap::BaseType.

Definition at line 117 of file Byte.cc.

Referenced by buf2val(), and val2buf().

Friends And Related Function Documentation

friend class Float32

friend

Definition at line 74 of file Byte.h.

friend class Float64

friend

Definition at line 75 of file Byte.h.

friend class Int16

friend

This class allows Int16, ..., Float64 access to <tt>_buf</tt> to

simplify and speed up the relational operators.

NB: According to Stroustrup it does not matter where (public, private or protected) friend classes are declared.

Definition at line 70 of file Byte.h.

friend class Int32

friend

Definition at line 72 of file Byte.h.

friend class UInt16

friend

Definition at line 71 of file Byte.h.

friend class UInt32

friend

Definition at line 73 of file Byte.h.

Member Data Documentation

dods_byte libdap::Byte::_buf

protected

Definition at line 78 of file Byte.h.

Referenced by buf2val(), Byte(), deserialize(), dump(), operator=(), ops(), print_val(), serialize(), set_value(), val2buf(), and value().

The documentation for this class was generated from the following files:

Public Types

Public Member Functions

Protected Member Functions

Protected Attributes

Friends

Detailed Description

Member Typedef Documentation

Constructor & Destructor Documentation

Member Function Documentation

Friends And Related Function Documentation

Member Data Documentation