- Steve Earl
FilterStream
FilterStream Methods
| FilterStream() | Constructor for the FilterStream class using an "associated stream" object |
| BytesAvailable() | Virtual method to return the number of bytes available to read before end of buffer |
| Pos() | Virtual method to return the current position within the associated stream |
| SetPos() | Virtual method to set the current position within the associated stream |
| DirectAccess() | Virtual method to return true or false for DirectAccess mode based on associated stream |
| EndOfStream() | Virtual method to return true if currently at end of associated stream |
| Read() | Virtual method to read a single 8 byte integer from the associated stream |
| Read() | Virtual method to read a single "small" integer from the associated stream (1, 2 or 4 bytes) |
| Read() | Virtual method to read a single float from the associated stream (4 or 8 bytes) |
| Read() | Virtual method to read a text string from the associated stream (default length or specific length) |
| Read() | Virtual method to read a boolean from the associated stream |
| Read() | Virtual method to read a binary buffer (stream) from the associated stream |
| Write() | Virtual method to write a single 8 byte integer to the associated stream |
| Write() | Virtual method to write a single "small" integer to the associated stream (1, 2 or 4 bytes) |
| Write() | Virtual method to write a single float to the associated stream (4 or 8 bytes) |
| Write() | Virtual method to write a single text string (default or specific length) |
| Write() | Virtual method to write a single boolean to the associated stream |
| Write() | Virtual method to write a binary buffer (stream) to the associated stream |
Derived Classes
See Also
Class Hierarchy, FileStream, MemoryStream, SocketStream, StreamException
public method FilterStream(StreamIO AssociatedStream)
Parameters
AssociatedStream
Stream object associated with this filter stream
Return Value
None
Description
Constructor for the FilterStream class. The "associated stream" is specified as the only argument. The I/O type (ReadOnly, WriteOnly or ReadWrite) is determined from the associated stream and is passed into the constructor for 'StreamIO'.
All I/O operations performed on a filter stream (any class derived from FilterStream) are actually performed on the associated stream behind the scenes.
FilterStream Class
public virtual method<int> BytesAvailable()
Parameters
None
Return Value
Number of bytes available to read
Description
Returns the number of bytes available to read from the associated stream. It is based on the current pointer position and the total size of the buffer.
FilterStream Class
public virtual method<int> Pos()
Parameters
None
Return Value
Current read/write pointer position
Description
Virtual method to return the current pointer position within the associated stream (one based). The next read or write operation takes place at this position.
FilterStream Class
public virtual method<bool> SetPos(int PointerPosition)
Parameters
PointerPosition
One based position in stream to read/write
Return Value
true if successul
Description
Virtual method to set the current read/write pointer position with the associated stream (one based), if applicable (based on "direct access"). The next read or write operation will take place at this position.
FilterStream Class
public virtual method<bool> DirectAccess()
Parameters
None
Return Value
Returns value of "direct access" flag
Description
Virtual method to return the direct access mode of the associated stream.
FilterStream Class
public virtual method<bool> EndOfStream()
Parameters
None
Return Value
Returns true if at end of stream
Description
Virtual method to return the value of the "end of stream" flag. If there are no bytes available in the associated stream to read, this method returns true and false if there are one or more bytes available to read.
FilterStream Class
public virtual method Read(int ref IntBucket, bool PeekOnly = false)
Parameters
IntBucket
Integer reference to receive the value
PeekOnly
If true, peek without reading/removing
Return Value
None
Description
Virtual method to read a single binary 8 byte integer value from the associated stream and copy the value into the IntBucket..
If the stream is specified as "WriteMode", this method will fire a StreamException.
FilterStream Class
public virtual method Read(int ref IntBucket, SmallInt IntSizeEnum, bool IsSigned = true, bool PeekOnly = false)
Parameters
IntBucket
Integer reference to receive the value
IntSizeEnum
Enumeration to indicate 1, 2 or 4 byte integer
IsSigned
Treat as signed integer If true, and unsigned if false (default is false)
PeekOnly
Peek without reading/removing if true (default is false)
Return Value
None
Description
Virtual method to read a single "small" binary integer value from the associated stream and copy the value into the IntBucket. The size of the integer read operation is specified by IntSizeEnum, and represents 1, 2 or 4 bytes. The "IsSigned" flag is also used to affect how the binary integer buffer is interpreted, signed or unsiged.
If the stream is specified as "WriteMode", this method will fire a StreamException.
FilterStream Class
public virtual method Read(float ref FloatBucket, bool Read32BitFloat = false, bool PeekOnly = false)
Parameters
FloatBucket
Float reference to receive the value
Read32BitFloat
Read 32 bit (4 byte) float if true (default is false)
PeekOnly
If true, read without advancing pointer
Return Value
None
Description
Virtual method to read a single binary floating point value from the associated stream and copy the value into the FloatBucket. The default size of the float read operation is 8 bytes, but can be changed to 4 bytes by setting the "Read32BitFloat" flag. If the "PeekOnly" flag is true, the value is read but the pointer position is not advanced, so the next read operation will read the same data.
If the stream is specified as "WriteMode", this method will fire a StreamException.
FilterStream Class
public virtual method Read(string ref StringBucket, bool ExtractLength = true, int ReadSize = 0, bool PeekOnly = false)
Parameters
StringBucket
String reference to receive the value
ExtractLength
Read the string length from the stream if true
ReadSize
Size of the read operation if ExtractLength is false
PeekOnly
If true, read without advancing pointer
Return Value
None
Description
Virtual method to read a single string from the associated stream and copy the value into the StringBucket. This supports reading a variable length string, and there are two ways of handling this. If the "ExtractLength" flag is true, the size of the string is actually read from the stream (as a 4 byte integer) and then the string read operation is dictacted by that size. If the "ExtractLength" flag is false, the "ReadSize" value is then used to dictate the length of the string to be read.
If the "PeekOnly" flag is true, the value is read but the pointer position is not advanced, so the next read operation will read the same data.
If the stream is specified as "WriteMode", this method will fire a StreamException.
FilterStream Class
public virtual method Read(bool ref BoolBucket, bool PeekOnly = false)
Parameters
BoolBucket
Boolean reference to receive the value
PeekOnly
If true, read without advancing pointer
Return Value
None
Description
Virtual method to read a single binary boolean value from the associated stream and copy the value into the BoolBucket. It is read as a one byte value. If the "PeekOnly" flag is true, the value is read but the pointer position is not advanced, so the next read operation will read the same data.
If the stream is specified as "WriteMode", this method will fire a StreamException.
FilterStream Class
public virtual method Read(StreamIO StreamBucket, int ReadSize = 0, bool PeekOnly = false)
Parameters
StreamBucket
Stream reference to receive the data
ReadSize
Size of the binary read operation
PeekOnly
If true, read without advancing pointer
Return Value
None
Description
Virtual method to read a binary block of data from the associated stream and write it into the target stream (StreamBucket). The size of the read operation is specified. If the target stream supports "random access", the data is written at the current pointer position within that target stream. If the "PeekOnly" flag is true, the value is read but the pointer position is not advanced, so the next read operation will read the same data.
If the ReadSize is specified as zero, the read operation goes all the way to the end of the associated stream.
If the stream is specified as "WriteMode", this method will fire a StreamException.
FilterStream Class
public virtual method Write(int Value)
Parameters
Value
Integer value to be written
Return Value
None
Description
Virtual method to write a single 8 byte binary integer value to the associated stream.
If the stream is specified as "ReadMode", this method will fire a StreamException.
FilterStream Class
public virtual method Write(int Value, SmallInt IntSizeEnum)
Parameters
Value
Integer value to be written
IntSizeEnum
Enumeration to indicate 1, 2 or 4 byte integer
Return Value
None
Description
Virtual method to write a single "small" binary integer value to the associated stream. The size of the integer write operation is specified by IntSizeEnum, and represents 1, 2 or 4 bytes. The integer value must fit within one of the two valid ranges for the integer size that was specified. For each integer size, there is a valid "signed" range and a separate value "unsigned" range. Refer to the 'int' class documention for more details.
If the stream is specified as "ReadMode", this method will fire a StreamException.
FilterStream Class
public virtual method Write(float Value, bool Write32BitFloat = false)
Parameters
Value
Float value to be written
Write32BitFloat
Write 32 bit (4 byte) float if true (default is false)
Return Value
None
Description
Virtual method to write a single binary floating point value to the associated stream. The default size of the float write operation is 8 bytes, but can be changed to 4 bytes by setting the "Write32BitFloat" flag. If the "Write32BitFlag" is set, the floating point value must fit within the valid range for a 4 byte float. Refer to the 'float' class documention for more details.
If the stream is specified as "ReadMode", this method will fire a StreamException.
FilterStream Class
public virtual method Write(string Value, bool EmbedLength = true, int OverrideLength = 0)
Parameters
Value
String value to be written to stream
EmbedLength
If true, embed string length into stream before the string
OverrideLength
Override length for string to be written
Return Value
None
Description
Virtual method to write a single string to the associated stream. If the "EmbedLength" flag is true, the length of the string is embedded in the stream before the text string itself (as a 4 byte integer). By default, the entire string is written to the stream, but if "OverrideLength" is greater than zero, then the override length will be used instead.
If the stream is specified as "ReadMode", this method will fire a StreamException.
FilterStream Class
public virtual method Write(bool Value)
Parameters
Value
Boolean value to be written
Return Value
None
Description
Virtual method to write a single binary boolean value to the associated stream. It is written as a one byte integer value repesenting the enumeration index.
If the stream is specified as "ReadMode", this method will fire a StreamException.
FilterStream Class
public virtual method Write(StreamIO SourceStream, int WriteSize = 0)
Parameters
SourceStream
Source stream reference
WriteSize
Size of the binary write operation
Return Value
None
Description
Virtual method to read a binary block of data from the source stream and write it into this associated stream. The size of the read and write operation is specified by "WriteSize". If the source stream supports "random access", the data is read from the current pointer position within that source stream and then written into this associated stream (at current pointer position). If the WriteSize is specified as zero, the read operation from the source stream goes all the way to the end of that stream.
If the stream is specified as "ReadMode", this method will fire a StreamException.
FilterStream Class