Gemstone.IO

Represents a file stream that caches recently used blocks in memory.

This class was developed as a wrapper around with the same basic functionality. This stream treats the file as a collection of contiguous blocks which can be loaded into an in-memory lookup table to greatly improve seek times. This class generally performs significantly better than the standard FileStream class when maintaining multiple file pointers and frequently seeking back and forth between them. For an example of a good use-case, consider copying a list of serialized objects from one location in the file to another without loading the whole list into memory. This class likely will not perform significantly better or worse than the standard FileStream when performing strictly sequential reads or writes. For an example of a bad use-case, consider reading a list of objects into memory or simply appending new data to the end of the file. In both of these cases, it may be better to use the standard FileStream for less memory overhead and more predictable flush behavior. Blocks are loaded into memory as they are used (for read/write operations) and will be kept in memory for as long as possible. Blocks can only be flushed from the cache by decreasing the cache size or by accessing a non-cached block when the cache is already full. In these cases, a least recently used algorithm is executed to determine which blocks should be removed from the cache either to decrease the size of the cache or to make room for a new block. Write operations are also cached such that they will not be committed to the file until the block is removed from the cache or a call to has been made. This can have some additional implications as compared to the standard FileStream. For instance, write operations may not be committed to the file in the order in which they were executed. Users of this class will need to be judicious about when and how often they call Flush.

Default value for the property.

Initializes a new instance of the class with the specified path, creation mode, read/write and sharing permission, the access other FileStreams can have to the same file, the buffer size, and additional file options.

A relative or absolute path for the file that the current FileStream object will encapsulate. A constant that determines how to open or create the file. is null. is an empty string (""), contains only white space, or contains one or more invalid characters. -or- refers to a non-file device, such as "con:", "com1:", "lpt1:", etc. in an NTFS environment. refers to a non-file device, such as "con:", "com1:", "lpt1:", etc. in a non-NTFS environment. contains an invalid value. The file cannot be found, such as when is FileMode.Truncate or FileMode.Open, and the file specified by does not exist. The file must already exist in these modes. An I/O error, such as specifying FileMode.CreateNew when the file specified by already exists, occurred.-or-The stream has been closed. The caller does not have the required permission. The specified path is invalid, such as being on an unmapped drive. The specified path, file name, or both exceed the system-defined maximum length. For example, on Windows-based platforms, paths must be less than 248 characters, and file names must be less than 260 characters.

A relative or absolute path for the file that the current FileStream object will encapsulate. A constant that determines how to open or create the file. A constant that determines how the file can be accessed by the FileStream object. This gets the and properties of the FileStream object. is true if specifies a disk file. A constant that determines how the file will be shared by processes. A positive value greater than 0 indicating the block size. For values between one and eight, the actual block size is set to eight bytes. is null. is an empty string (""), contains only white space, or contains one or more invalid characters. -or- refers to a non-file device, such as "con:", "com1:", "lpt1:", etc. in an NTFS environment. refers to a non-file device, such as "con:", "com1:", "lpt1:", etc. in a non-NTFS environment. is negative or zero.-or- , , or contain an invalid value. The file cannot be found, such as when is FileMode.Truncate or FileMode.Open, and the file specified by does not exist. The file must already exist in these modes. An I/O error, such as specifying FileMode.CreateNew when the file specified by already exists, occurred.-or-The stream has been closed. The caller does not have the required permission. The specified path is invalid, such as being on an unmapped drive. The requested is not permitted by the operating system for the specified , such as when is Write or ReadWrite and the file or directory is set for read-only access. The specified path, file name, or both exceed the system-defined maximum length. For example, on Windows-based platforms, paths must be less than 248 characters, and file names must be less than 260 characters.

A relative or absolute path for the file that the current FileStream object will encapsulate. A constant that determines how to open or create the file. A constant that determines how the file can be accessed by the FileStream object. This gets the and properties of the FileStream object. is true if specifies a disk file. A constant that determines how the file will be shared by processes. A positive value greater than 0 indicating the block size. For values between one and eight, the actual block size is set to eight bytes. Specifies whether to use asynchronous I/O or synchronous I/O. However, note that the underlying operating system might not support asynchronous I/O, so when specifying true, the handle might be opened synchronously depending on the platform. When opened asynchronously, the and methods perform better on large reads or writes, but they might be much slower for small reads or writes. If the application is designed to take advantage of asynchronous I/O, set the parameter to true. Using asynchronous I/O correctly can speed up applications by as much as a factor of 10, but using it without redesigning the application for asynchronous I/O can decrease performance by as much as a factor of 10. is null. is an empty string (""), contains only white space, or contains one or more invalid characters. -or- refers to a non-file device, such as "con:", "com1:", "lpt1:", etc. in an NTFS environment. refers to a non-file device, such as "con:", "com1:", "lpt1:", etc. in a non-NTFS environment. is negative or zero.-or- , , or contain an invalid value. The file cannot be found, such as when is FileMode.Truncate or FileMode.Open, and the file specified by does not exist. The file must already exist in these modes. An I/O error, such as specifying FileMode.CreateNew when the file specified by already exists, occurred.-or-The stream has been closed. The caller does not have the required permission. The specified path is invalid, such as being on an unmapped drive. The requested is not permitted by the operating system for the specified , such as when is Write or ReadWrite and the file or directory is set for read-only access. The specified path, file name, or both exceed the system-defined maximum length. For example, on Windows-based platforms, paths must be less than 248 characters, and file names must be less than 260 characters.

A relative or absolute path for the file that the current FileStream object will encapsulate. A constant that determines how to open or create the file. A constant that determines how the file can be accessed by the FileStream object. This gets the and properties of the FileStream object. is true if specifies a disk file. A constant that determines how the file will be shared by processes. A positive value greater than 0 indicating the block size. For values between one and eight, the actual block size is set to eight bytes. A value that specifies additional file options. is null. is an empty string (""), contains only white space, or contains one or more invalid characters. -or- refers to a non-file device, such as "con:", "com1:", "lpt1:", etc. in an NTFS environment. refers to a non-file device, such as "con:", "com1:", "lpt1:", etc. in a non-NTFS environment. is negative or zero.-or- , , or contain an invalid value. The file cannot be found, such as when is FileMode.Truncate or FileMode.Open, and the file specified by does not exist. The file must already exist in these modes. An I/O error, such as specifying FileMode.CreateNew when the file specified by already exists, occurred.-or-The stream has been closed. The caller does not have the required permission. The specified path is invalid, such as being on an unmapped drive. The requested is not permitted by the operating system for the specified , such as when is Write or ReadWrite and the file or directory is set for read-only access. -or- is specified for , but file encryption is not supported on the current platform. The specified path, file name, or both exceed the system-defined maximum length. For example, on Windows-based platforms, paths must be less than 248 characters, and file names must be less than 260 characters.

Gets the size of the cached blocks.

Gets or sets the maximum size of the cache.

Cache size is set to a value less than zero.

When overridden in a derived class, gets a value indicating whether the current stream supports reading.

true if the stream supports reading; otherwise, false. 1

When overridden in a derived class, gets a value indicating whether the current stream supports writing.

true if the stream supports writing; otherwise, false. 1

When overridden in a derived class, gets a value indicating whether the current stream supports seeking.

true if the stream supports seeking; otherwise, false. 1

When overridden in a derived class, gets or sets the position within the current stream.

The current position within the stream. Methods were called after the stream was closed. 1

When overridden in a derived class, gets the length in bytes of the stream.

A long value representing the length of the stream in bytes. Methods were called after the stream was closed. 1

When overridden in a derived class, sets the position within the current stream.

The new position within the current stream. A byte offset relative to the parameter. A value of type indicating the reference point used to obtain the new position. Methods were called after the stream was closed. 1

When overridden in a derived class, reads a sequence of bytes from the current stream and advances the position within the stream by the number of bytes read.

An array of bytes. When this method returns, the buffer contains the specified byte array with the values between and ( + - 1) replaced by the bytes read from the current source. The zero-based byte offset in at which to begin storing the data read from the current stream. The maximum number of bytes to be read from the current stream. The total number of bytes read into the buffer. This can be less than the number of bytes requested if that many bytes are not currently available, or zero (0) if the end of the stream has been reached. and describe an invalid range in . is null. or is negative. An I/O error occurs. The stream does not support reading. Methods were called after the stream was closed. 1

When overridden in a derived class, writes a sequence of bytes to the current stream and advances the current position within this stream by the number of bytes written.

An array of bytes. This method copies bytes from to the current stream. The zero-based byte offset in at which to begin copying bytes to the current stream. The number of bytes to be written to the current stream. and describe an invalid range in . is null. or is negative. An I/O error occurs. The stream does not support writing. Methods were called after the stream was closed. 1

Clears buffers for this stream and causes any buffered data to be written to the file.

An I/O error occurs. 2

Clears buffers for this stream and causes any buffered data to be written to the file, and also clears all intermediate file buffers.

true to flush all intermediate file buffers; otherwise, false. An I/O error occurs. 2

When overridden in a derived class, sets the length of the current stream.

The desired length of the current stream in bytes. Attempted to set the parameter to less than 0. An I/O error occurs. The stream does not support both writing and seeking. Methods were called after the stream was closed. 2

Releases the unmanaged resources used by the and optionally releases the managed resources.

true to release both managed and unmanaged resources; false to release only unmanaged resources.

Generates an Adler-32 checksum calculation.

Creates a new instance of the class.

Returns the Adler-32 data checksum computed so far.

Resets the Adler-32 data checksum as if no update was ever called.

Updates the checksum with the byte value.

The value to use for the update.

Updates the checksum with the bytes taken from the array.

buffer an array of bytes

Adds the byte array to the data checksum.

The buffer which contains the data The offset in the buffer where the data starts The number of data bytes to update the checksum with.

Defines extension functions related to computing checksums.

Calculates the Adler-32 checksum on specified portion of a buffer.

Data buffer to perform checksum on. Starts index in data buffer to begin checksum. Total number of bytes from startIndex to perform checksum over. Computed Adler-32 checksum over the specified portion of the buffer.

Calculates the CRC16 check-sum on specified portion of a buffer.

Data buffer to perform check-sum on. Starts index in data buffer to begin check-sum. Total number of bytes from startIndex to perform check-sum over. Computed CRC16 checksum over the specified portion of the buffer.

Calculates the CRC-CCITT check-sum on specified portion of a buffer.

Data buffer to perform check-sum on. Starts index in data buffer to begin check-sum. Total number of bytes from startIndex to perform check-sum over. Computed CRC-CCITT checksum over the specified portion of the buffer. The CRC-CCITT is a table based 16-bit CRC popular for modem protocols defined for use by the Consultative Committee on International Telegraphy and Telephony (CCITT)

Calculates the CRC-ModBus check-sum on specified portion of a buffer.

Data buffer to perform check-sum on. Starts index in data buffer to begin check-sum. Total number of bytes from startIndex to perform check-sum over. Computed CRC-ModBus checksum over the specified portion of the buffer.

Calculates the CRC32 check-sum on specified portion of a buffer.

Data buffer to perform check-sum on. Starts index in data buffer to begin check-sum. Total number of bytes from startIndex to perform check-sum over. Computed CRC32 checksum over the specified portion of the buffer.

Calculates byte length (8-bit) XOR-based check-sum on specified portion of a buffer.

Data buffer to perform XOR check-sum on. Starts index in data buffer to begin XOR check-sum. Total number of bytes from startIndex to perform XOR check-sum over. Byte length XOR check-sum.

Calculates word length (16-bit) XOR-based check-sum on specified portion of a buffer.

Data buffer to perform XOR check-sum on. Starts index in data buffer to begin XOR check-sum. Total number of bytes from startIndex to perform XOR check-sum overs Word length XOR check-sum.

Calculates double-word length (32-bit) XOR-based check-sum on specified portion of a buffer.

Data buffer to perform XOR check-sum on. Starts index in data buffer to begin XOR check-sum. Total number of bytes from startIndex to perform XOR check-sum over. Double-word length XOR check-sum.

Calculates quad-word length (64-bit) XOR-based check-sum on specified portion of a buffer.

Data buffer to perform XOR check-sum on. Starts index in data buffer to begin XOR check-sum. Total number of bytes from startIndex to perform XOR check-sum over. Quad-word length XOR check-sum.

Indicates type of CRC-16 calculation performed.

Regular CRC-16 calculation.

ModBus CRC-16 calculation.

Generates a byte-wise 16-bit CRC calculation.

2-byte (16-bit) CRC: The generating polynomial is 16 15 2 1 G(X) = X + X + X + X

Creates a new instance of the Crc16 class. The checksum starts off with a value of 0x0000.

Creates a new instance of the Crc16 class.

Type of calculation to perform, CRC-16 or ModBus.

Returns the CRC-16 data checksum computed so far.

Resets the CRC-16 data checksum as if no update was ever called.

Type of CRC calculation. CRC-16 resets to 0x0000, ModBus resets to 0xFFFF

Updates the checksum with the byte value.

The value to use for the update.

Updates the checksum with the bytes taken from the array.

buffer an array of bytes

Adds the byte array to the data checksum.

The buffer which contains the data The offset in the buffer where the data starts The number of data bytes to update the CRC with.

Generates a byte-wise 32-bit CRC calculation.

Returns the CRC-32 data checksum computed so far.

Resets the CRC-32 data checksum as if no update was ever called.

Updates the checksum with the integer value.

The value to use for the update.

Updates the checksum with the bytes taken from the array.

buffer an array of bytes

Adds the byte array to the data checksum.

The buffer which contains the data The offset in the buffer where the data starts The number of data bytes to update the CRC with.

Calculates the CRC32 check-sum on specified portion of a buffer.

Data buffer to perform check-sum on. Starts index in data buffer to begin check-sum. Total number of bytes from offset to perform check-sum over. Computed CRC32 checksum over the specified portion of the buffer.

Generates a 16-bit CRC-CCITT checksum.

This is a table based 16-bit CRC popular for modem protocols defined for use by the Consultative Committee on International Telegraphy and Telephony (CCITT)

Creates a new instance of the CrcCCITT class. The checksum starts off with a value of 0xFFFF.

Returns the CRCCCITT data checksum computed so far.

Resets the CRC-CCITT data checksum as if no update was ever called.

Updates the checksum with the byte value.

The value to use for the update.

Updates the checksum with the bytes taken from the array.

buffer an array of bytes

Adds the byte array to the data checksum.

The buffer which contains the data The offset in the buffer where the data starts The number of data bytes to update the CRC with.

Contains classes and extension functions used to calculate standard checksums and CRC’s.

Calculates word length (16-bit) XOR-based check-sum on specified portion of a buffer.

Creates a new instance of the Xor16Bit class. The checksum starts off with a value of 0.

Returns the Xor 16-bit checksum computed so far.

Resets the checksum to the initial value.

Updates the checksum with a ushort value.

The value to use for the update.

Updates the checksum with an array of bytes.

The source of the data to update with.

Updates the checksum with the bytes taken from the array.

an array of bytes the start of the data used for this update the number of bytes to use for this update

Calculates double-word length (32-bit) XOR-based check-sum on specified portion of a buffer.

Creates a new instance of the Xor32Bit class. The checksum starts off with a value of 0.

Returns the Xor 32-bit checksum computed so far.

Resets the checksum to the initial value.

Updates the checksum with a uint value.

The value to use for the update.

Updates the checksum with an array of bytes.

The source of the data to update with.

Updates the checksum with the bytes taken from the array.

an array of bytes the start of the data used for this update the number of bytes to use for this update

Calculates quad-word length (64-bit) XOR-based check-sum on specified portion of a buffer.

Creates a new instance of the Xor64Bit class. The checksum starts off with a value of 0.

Returns the Xor 64-bit checksum computed so far.

Resets the checksum to the initial value.

Updates the checksum with a ulong value.

The value to use for the update.

Updates the checksum with an array of bytes.

The source of the data to update with.

Updates the checksum with the bytes taken from the array.

an array of bytes the start of the data used for this update the number of bytes to use for this update

Calculates byte length (8-bit) XOR-based check-sum on specified portion of a buffer.

Creates a new instance of the Xor8Bit class. The checksum starts off with a value of 0.

Returns the Xor 8-bit checksum computed so far.

Resets the checksum to the initial value.

Updates the checksum with a byte value.

The value to use for the update.

Updates the checksum with an array of bytes.

The source of the data to update with.

Updates the checksum with the bytes taken from the array.

an array of bytes the start of the data used for this update the number of bytes to use for this update

Represents a lookup table of key/value pairs backed by a file, with very little memory overhead.

The type of the keys in the lookup table. The type of the values in the lookup table.

Represents a lookup table of key/value pairs backed by a file, with very little memory overhead.

The type of the keys in the lookup table. The type of the values in the lookup table. The element type of when it is a type; otherwise, . The element type of when it is a type; otherwise, .

Creates a new instance of the class.

Either or cannot be serialized. This constructor uses the default equality comparer for file backed lookup tables, which is not the same as the default equality comparer for objects. This is because the default implementation of does not provide guarantees about consistency across platforms, or even implementations of the CLR. Instead, the default equality comparer uses a byte-for-byte comparison to determine equality between keys and a CRC-32 for its hash code implementation. This means the performance of the hashing function is dependent on the performance of the serialization function.

Creates a new instance of the class.

The path to the file used to store the lookup table. is a zero-length string, contains only white space, or contains one or more invalid characters as defined by . is null. Either or cannot be serialized. This constructor uses the default equality comparer for file backed lookup tables, which is not the same as the default equality comparer for objects. This is because the default implementation of does not provide guarantees about consistency across platforms, or even implementations of the CLR. Instead, the default equality comparer uses a byte-for-byte comparison to determine equality between keys and a CRC-32 for its hash code implementation. This means the performance of the hashing function is dependent on the performance of the serialization function.

Creates a new instance of the class.

The dictionary whose elements are copied to this dictionary. is null. Either or cannot be serialized. This constructor uses the default equality comparer for file backed lookup tables, which is not the same as the default equality comparer for objects. This is because the default implementation of does not provide guarantees about consistency across platforms, or even implementations of the CLR. Instead, the default equality comparer uses a byte-for-byte comparison to determine equality between keys and a CRC-32 for its hash code implementation. This means the performance of the hashing function is dependent on the performance of the serialization function.

Creates a new instance of the class.

The equality comparer used to compare keys in the dictionary. Either or cannot be serialized.

Creates a new instance of the class.

The path to the file used to store the lookup table. The dictionary whose elements are copied to this dictionary. is a zero-length string, contains only white space, or contains one or more invalid characters as defined by . is null or is null. Either or cannot be serialized. This constructor uses the default equality comparer for file backed lookup tables, which is not the same as the default equality comparer for objects. This is because the default implementation of does not provide guarantees about consistency across platforms, or even implementations of the CLR. Instead, the default equality comparer uses a byte-for-byte comparison to determine equality between keys and a CRC-32 for its hash code implementation. This means the performance of the hashing function is dependent on the performance of the serialization function.

Creates a new instance of the class.

The path to the file used to store the lookup table. The equality comparer used to compare keys in the dictionary. is a zero-length string, contains only white space, or contains one or more invalid characters as defined by . is null. Either or cannot be serialized.

Creates a new instance of the class.

The dictionary whose elements are copied to this dictionary. The equality comparer used to compare keys in the dictionary. is null. Either or cannot be serialized.

Creates a new instance of the class.

The path to the file used to store the lookup table. The dictionary whose elements are copied to this dictionary. The equality comparer used to compare keys in the dictionary. is a zero-length string, contains only white space, or contains one or more invalid characters as defined by . is null or is null. Either or cannot be serialized.

Gets or sets the path to the file backing this dictionary.

FilePath is set and is a zero-length string, contains only white space, or contains one or more invalid characters as defined by . Changes to this property will cause the file to close if the file is already opened. Data will not be automatically written from the old file to the new file.

Gets the number of elements contained in the .

The number of elements contained in the .

Gets a value indicating whether the is read-only.

true if the is read-only; otherwise, false.

Gets the default signature used by the if no user-defined signature is supplied.

Gets or sets the signature of the file backing the lookup table.

Attempt is made to set Signature to a null value. Attempt is made to set Signature to a value larger than the maximum allowed size. Attempt is made to modify Signature of a read-only lookup table.

Gets or sets the element with the specified key.

The element with the specified key. The key of the element to get or set. is null. The property is retrieved and is not found. The property is set and the is read-only.

Gets an containing the keys of the .

An containing the keys of the object that implements .

Gets an containing the values in the .

An containing the values in the object that implements .

Gets or sets the size of the cache used to store data from the file in memory.

Gets the number of operations that fragment the lookup table that have occurred since the last time the lookup table was compacted.

This value is not stored in the file and may therefore be inaccurate if the lookup table has not been compacted since the last time it was opened.

Opens the file backing this dictionary.

File is already open.

Opens the file backing this hash set in read-only mode.

File is already open.

Adds an element with the provided key and value to the .

The object to use as the key of the element to add. The object to use as the value of the element to add. is null. An element with the same key already exists in the . The is read-only.

Adds an item to the .

The object to add to the . The is read-only.

Removes the element with the specified key from the .

true if the element is successfully removed; otherwise, false. This method also returns false if was not found in the original . The key of the element to remove. is null. The is read-only.

Removes the first occurrence of a specific object from the .

true if was successfully removed from the ; otherwise, false. This method also returns false if is not found in the original . The object to remove from the . The is read-only.

Determines whether the contains an element with the specified key.

true if the contains an element with the key; otherwise, false. The key to locate in the . is null.

Determines whether the contains a specific value.

true if is found in the ; otherwise, false. The object to locate in the .

Gets the value associated with the specified key.

true if the object that implements contains an element with the specified key; otherwise, false. The key whose value to get. When this method returns, the value associated with the specified key, if the key is found; otherwise, the default value for the type of the parameter. This parameter is passed uninitialized. is null.

Removes all items from the .

The is read-only.

Copies the elements of the to an , starting at a particular index.

The one-dimensional that is the destination of the elements copied from . The must have zero-based indexing.The zero-based index in at which copying begins. is null. is less than 0. The number of elements in the source is greater than the available space from to the end of the destination .

Returns an enumerator that iterates through the collection.

A that can be used to iterate through the collection. 1

Gets an enumerable used to iterate only the keys in the dictionary.

An enumerable used to iterate only the keys in the dictionary.

Gets an enumerable used to iterate only the values in the dictionary.

An enumerable used to iterate only the values in the dictionary.

Defragments the item section of the dictionary, which gets fragmented after removing keys or updating values.

Closes the file backing this dictionary.

Releases all the resources used by the object.

Returns an enumerator that iterates through a collection.

An object that can be used to iterate through the collection. 2

Represents a lookup table backed by a file, with very little memory overhead.

The type of the items in the lookup table.

Represents a lookup table backed by a file, with very little memory overhead.

The type of the items in the lookup table. The element type of when it is a type; otherwise, .

Creates a new instance of the class.

cannot be serialized. This constructor uses the default equality comparer for file backed lookup tables, which is not the same as the default equality comparer for objects. This is because the default implementation of does not provide guarantees about consistency across platforms, or even implementations of the CLR. Instead, the default equality comparer uses a byte-for-byte comparison to determine equality between keys and a CRC-32 for its hash code implementation. This means the performance of the hashing function is dependent on the performance of the serialization function.

Creates a new instance of the class.

The path to the file used to store the lookup table. is a zero-length string, contains only white space, or contains one or more invalid characters as defined by . is null. cannot be serialized. This constructor uses the default equality comparer for file backed lookup tables, which is not the same as the default equality comparer for objects. This is because the default implementation of does not provide guarantees about consistency across platforms, or even implementations of the CLR. Instead, the default equality comparer uses a byte-for-byte comparison to determine equality between keys and a CRC-32 for its hash code implementation. This means the performance of the hashing function is dependent on the performance of the serialization function.

Creates a new instance of the class.

The equality comparer used to compare items in the hash set. cannot be serialized.

Creates a new instance of the class.

The enumerable whose elements are copied to this hash set. is null. cannot be serialized. This constructor uses the default equality comparer for file backed lookup tables, which is not the same as the default equality comparer for objects. This is because the default implementation of does not provide guarantees about consistency across platforms, or even implementations of the CLR. Instead, the default equality comparer uses a byte-for-byte comparison to determine equality between keys and a CRC-32 for its hash code implementation. This means the performance of the hashing function is dependent on the performance of the serialization function.

Creates a new instance of the class.

The path to the file used to store the lookup table. The equality comparer used to compare items in the hash set. is a zero-length string, contains only white space, or contains one or more invalid characters as defined by . is null. cannot be serialized.

Creates a new instance of the class.

The path to the file used to store the lookup table. The enumerable whose elements are copied to this hash set. is a zero-length string, contains only white space, or contains one or more invalid characters as defined by . is null or is null. cannot be serialized. This constructor uses the default equality comparer for file backed lookup tables, which is not the same as the default equality comparer for objects. This is because the default implementation of does not provide guarantees about consistency across platforms, or even implementations of the CLR. Instead, the default equality comparer uses a byte-for-byte comparison to determine equality between keys and a CRC-32 for its hash code implementation. This means the performance of the hashing function is dependent on the performance of the serialization function.

Creates a new instance of the class.

The enumerable whose elements are copied to this hash set. The equality comparer used to compare items in the hash set. is null. cannot be serialized.

Creates a new instance of the class.

The path to the file used to store the lookup table. The enumerable whose elements are copied to this hash set. The equality comparer used to compare items in the hash set. is a zero-length string, contains only white space, or contains one or more invalid characters as defined by . is null or is null. cannot be serialized.

Gets or sets the path to the file backing this hash set.

Gets the number of elements contained in the .

The number of elements contained in the .

Gets a value indicating whether the is read-only.

true if the is read-only; otherwise, false.

Gets the default signature used by the if no user-defined signature is supplied.

Gets or sets the signature of the file backing the lookup table.

Attempt is made to set Signature to a null value. Attempt is made to set Signature to a value larger than the maximum allowed size. Attempt is made to modify Signature of a read-only lookup table.

Gets or sets the size of the cache used to store data from the file in memory.

Gets the number of operations that fragment the lookup table that have occurred since the last time the lookup table was compacted.

This value is not stored in the file and may therefore be inaccurate if the lookup table has not been compacted since the last time it was opened.

Opens the file backing this hash set.

File is already open.

Opens the file backing this hash set in read-only mode.

File is already open.

Adds an element to the current set and returns a value to indicate if the element was successfully added.

The element to add to the set. true if the element is added to the set; false if the element is already in the set.

Removes the first occurrence of a specific object from the .

The object to remove from the . true if was successfully removed from the ; otherwise, false. This method also returns false if is not found in the original . The is read-only.

Removes all elements that match the conditions defined by the specified predicate from a collection.

The delegate that defines the conditions of the elements to remove. The number of elements that were removed from the collection. match is null The is read-only.

Determines whether the contains a specific value.

The object to locate in the . true if is found in the ; otherwise, false.

Modifies the current set so that it contains all elements that are present in either the current set or the specified collection.

The collection to compare to the current set. is null. The is read-only.

Modifies the current set so that it contains only elements that are also in a specified collection.

The collection to compare to the current set. is null. The is read-only.

Removes all elements in the specified collection from the current set.

The collection of items to remove from the set. is null. The is read-only.

Modifies the current set so that it contains only elements that are present either in the current set or in the specified collection, but not both.

The collection to compare to the current set. is null. The is read-only.

Determines whether a set is a subset of a specified collection.

The collection to compare to the current set. true if the current set is a subset of ; otherwise, false. is null. The is read-only.

Determines whether the current set is a superset of a specified collection.

The collection to compare to the current set. true if the current set is a superset of ; otherwise, false. is null.

Determines whether the current set is a proper (strict) superset of a specified collection.

The collection to compare to the current set. true if the current set is a proper superset of ; otherwise, false. is null. The is read-only.

Determines whether the current set is a proper (strict) subset of a specified collection.

The collection to compare to the current set. true if the current set is a proper subset of ; otherwise, false. is null. The is read-only.

Determines whether the current set overlaps with the specified collection.

The collection to compare to the current set. true if the current set and share at least one common element; otherwise, false. is null.

Determines whether the current set and the specified collection contain the same elements.

The collection to compare to the current set. true if the current set is equal to ; otherwise, false. is null. The is read-only.

Removes all items from the .

The is read-only.

Copies the elements of the to an , starting at a particular index.

The one-dimensional that is the destination of the elements copied from . The must have zero-based indexing. The zero-based index in at which copying begins. is null. is less than 0. The number of elements in the source is greater than the available space from to the end of the destination .

Returns an enumerator that iterates through the collection.

A that can be used to iterate through the collection. 1

Defragments the item section of the hash set, which gets fragmented after removing items.

Closes the file backing this hash set.

Releases all the resources used by the object.

Adds an item to the .

The object to add to the . The is read-only.

Returns an enumerator that iterates through a collection.

An object that can be used to iterate through the collection. 2

Dictionary with keys and values in the item nodes.

HashSet with lookup node markers for set operations.

Defines signature for dictionaries.

Defines signature for hash sets.

Creates a new instance of the class.

Type of the lookup table used to tweak the file format. Either or cannot be serialized.

Creates a new instance of the class.

Type of the lookup table used to tweak the file format. The path to the file used to store the lookup table. is a zero-length string, contains only white space, or contains one or more invalid characters as defined by . is null. Either or cannot be serialized.

Creates a new instance of the class.

Type of the lookup table used to tweak the file format. The equality comparer used to compare keys in the lookup table. Either or cannot be serialized.

Creates a new instance of the class.

Type of the lookup table used to tweak the file format. The path to the file used to store the lookup table. The equality comparer used to compare keys in the lookup table. is a zero-length string, contains only white space, or contains one or more invalid characters as defined by . is null. Either or cannot be serialized.

Gets or sets the path to the file backing this lookup table.

FilePath contains one or more invalid characters as defined by . Changes to this property will cause the file to close if the file is already opened. Data will not be automatically written from the old file to the new file.

Gets the number of elements contained in the .

The number of elements contained in the .

Gets a value indicating whether the is read-only.

true if the is read-only; otherwise, false.

Gets or sets the signature of the file backing the lookup table.

Attempt is made to set Signature to a null value. Attempt is made to set Signature to a value larger than the maximum allowed size. Attempt is made to modify Signature of a read-only lookup table.

Gets or sets the element with the specified key.

The element with the specified key. The key of the element to get or set. is null. The property is retrieved and is not found. The property is set and the is read-only.

Gets or sets the size of the cache used to store data from the file in memory.

Gets the number of operations that fragment the lookup table that have occurred since the last time the lookup table was compacted.

This value is not stored in the file and may therefore be inaccurate if the lookup table has not been compacted since the last time it was opened.

Opens the file backing this lookup table.

File is already open.

Opens the file backing this lookup table in read-only mode.

File is already open or the file has a pending transaction that could not be completed. The format of the file is invalid.

Adds an element with the provided key and value to the .

The object to use as the key of the element to add. The object to use as the value of the element to add. is null. An element with the same key already exists in the . The is read-only.

Adds an element with the provided key and value to the .

The object to use as the key of the element to add. The object to use as the value of the element to add. True if the item was successfully added; false otherwise. is null. An element with the same key already exists in the . The is read-only.

Removes the element with the specified key from the .

true if the element is successfully removed; otherwise, false. This method also returns false if was not found in the original . The key of the element to remove. is null. The is read-only.

Attempts to find the lookup node for the corresponding key and, if found, marks the lookup node.

The key used to find the lookup node to be marked. The is read-only.

Determines whether all occupied lookup nodes are marked.

True if all occupied lookup nodes are marked; false otherwise. The is read-only.

Removes all unmarked nodes from the hash set.

The is read-only.

Removes all unmarked nodes from the hash set.

The is read-only.

Unmarks all lookup nodes in the hash set.

The is read-only.

Determines whether the contains an element with the specified key.

true if the contains an element with the key; otherwise, false. The key to locate in the . is null.

Gets the value associated with the specified key.

Removes all items from the .

The is read-only.

Returns an enumerator that iterates through the collection.

A that can be used to iterate through the collection. 1

Gets an enumerable used to iterate only the keys in the lookup table.

An enumerable used to iterate only the keys in the lookup table.

Defragments the item section of the lookup table, which gets fragmented after removing keys or updating values.

Closes the file backing this lookup table.

Releases all the resources used by the object.

Returns an enumerator that iterates through a collection.

An object that can be used to iterate through the collection. 2

Represents a rolling window of data with FIFO semantics that will automatically truncate the data when the window size is exceeded.

The type of objects to be stored in the rolling window.

Creates a new instance of the class.

The size of the window maintained by the collection.

Gets the number of elements contained in the .

Gets the size of the window maintained by the .

Gets a value indicating whether the is read-only.

Gets or sets the element at the specified index.

The element at the specified index. The zero-based index of the element to get or set. is not a valid index in the .

Adds an item to the .

The object to add to the .

Inserts an item to the at the specified index.

The zero-based index at which should be inserted. The object to insert into the . is not a valid index in the . Rolling window is full ( = .

Removes the first occurrence of a specific object from the .

true if was successfully removed from the ; otherwise, false. This method also returns false if is not found in the original . The object to remove from the .

Removes the item at the specified index.

The zero-based index of the item to remove. is not a valid index in the .

Determines the index of a specific item in the .

The index of if found in the list; otherwise, -1. The object to locate in the .

Determines whether the contains a specific value.

true if is found in the ; otherwise, false. The object to locate in the .

Removes all items from the .

Copies the elements of the to an , starting at a particular index.

The one-dimensional that is the destination of the elements copied from . The must have zero-based indexing. The zero-based index in at which copying begins. is null. is less than 0. The number of elements in the source is greater than the available space from to the end of the destination .

Returns an enumerator that iterates through the collection.

A that can be used to iterate through the collection. 1

Returns an enumerator that iterates through a collection.

An object that can be used to iterate through the collection. 2

Represents a destination location when exporting data using .

Constructs a new .

Constructs a new given the specified parameters.

Path and file name of export destination. Determines whether to attempt network connection to share specified in . Domain used to authenticate network connection if is true. Username used to authenticate network connection if is true. Password used to authenticate network connection if is true.

Path and file name of export destination.

Determines whether to attempt network connection to share specified in .

Domain used to authenticate network connection if is true.

Username used to authenticate network connection if is true.

Password used to authenticate network connection if is true.

Path root of (e.g., E:\ or \\server\share).

Path and filename of without drive or server share prefix.

Returns a that represents the current .

A that represents the current .

Handles the exporting of a file to multiple destinations that are defined in the config file.

This class is useful for updating the same file on multiple servers (e.g., load balanced web server). This example shows the use for exporting data to multiple locations:


             using System;
             using Gemstone.IO;
            
             class Program
             {
                 static MultipleDestinationExporter s_exporter;
            
                 static void Main(string[] args)
                 {
                     s_exporter = new MultipleDestinationExporter();
                     s_exporter.Initialized += s_exporter_Initialized;
                     ExportDestination[] defaultDestinations = new ExportDestination[] 
                     {
                         new ExportDestination(@"\\server1\share\exportFile.txt", false, "domain", "user1", "password1"), 
                         new ExportDestination(@"\\server2\share\exportFile.txt", false, "domain", "user2", "password2")
                     };
                     // Initialize with the destinations where data is to be exported.
                     s_exporter.Initialize(defaultDestinations);
            
                     Console.ReadLine();
                 }
            
                 static void s_exporter_Initialized(object sender, EventArgs e)
                 {
                     // Export data to all defined locations after initialization.
                     s_exporter.ExportData("TEST DATA");
                 }
             }

This example shows the config file entry that can be used to specify the used by the when exporting data:

Defines state information for an export.

Creates a new .

Releases the unmanaged resources before the object is reclaimed by .

Gets or sets the source file name for the .

Gets or sets the destination file name for the .

Gets or sets the event wait handle for the .

Gets or sets a flag that is used to determine if export process has timed out.

Releases all the resources used by the object.

Releases the unmanaged resources used by the object and optionally releases the managed resources.

true to release both managed and unmanaged resources; false to release only unmanaged resources.

Specifies the default value for the property.

Occurs when the object has been initialized.

Occurs when status information for the object is being reported.

is the status message being reported by the .

Event is raised when there is an exception encountered while processing.

is the exception that was thrown.

Initializes a new instance of the class.

The config file settings category under which the export destinations are defined. The total allowed time in milliseconds for each export to execute.

Gets or sets the total allowed time in milliseconds for each export to execute.

Set to Timeout.Infinite (-1) for no timeout.

Gets or sets the maximum number of retries that will be attempted during an export if the export fails.

Total file export attempts = 1 + . Set to zero to only attempt export once.

Gets or sets the interval to wait, in milliseconds, before retrying an export if the export fails.

Gets or sets a boolean value that indicates whether the settings of object are to be saved to the config file.

Gets or sets the category under which the settings of object are to be saved to the config file if the property is set to true.

The value being assigned is null or empty string.

Gets or sets the to be used to encode text data being exported.

Gets or sets a boolean value that indicates whether the object is currently enabled.

Gets the total number exports performed successfully.

Gets a list of currently defined .

Use the method to change the export destination collection.

Gets the unique identifier of the object.

Gets the descriptive status of the object.

Releases all the resources used by the object.

Releases the unmanaged resources used by the object and optionally releases the managed resources.

true to release both managed and unmanaged resources; false to release only unmanaged resources.

Initializes (or re-initializes) from configuration settings.

If not being used as a component (i.e., user creates their own instance of this class), this method must be called in order to initialize exports. Event if used as a component this method can be called at anytime to reinitialize the exports with new configuration information.

Initializes (or re-initializes) from configuration settings.

Provides a default set of export destinations if none exist in configuration settings. If not being used as a component (i.e., user creates their own instance of this class), this method must be called in order to initialize exports. Even if used as a component this method can be called at anytime to reinitialize the exports with new configuration information.

Raises the event.

Status message to report. parameters used for status message.

Raises event.

Processing .

Start multiple file export.

Text based data to export to each destination. This is assumed to be the full content of the file to export. This class does not queue data since the export is not intended to append to an existing file but rather replace an existing one.

Start multiple file export.

Binary data to export to each destination. This is assumed to be the full content of the file to export. This class does not queue data since the export is not intended to append to an existing file but rather replace an existing one.

The namespace organizes all Gemstone library functionality related to Input and Output (IO). The root namespace also includes common IO related classes, e.g., .

Represents the base class for a common binary image header implementation.

Here is an example of a possible derived class constructor that has an integer TypeID as the first 4 bytes in the image:


            public CommonHeader(object state, byte[] binaryImage, int startIndex, int length)
            {
                if (length > 3)
                {
                    TypeID = LittleEndian.ToInt32(binaryImage, startIndex);
                    State = state;
                }
                else
                    throw new InvalidOperationException("Malformed image");
            }

Type of identifier used to distinguish output types.

Gets or sets the identifier used for identifying the to be parsed.

Gets or sets any additional state information that might be needed for parsing.

This class defines a basic implementation of parsing functionality suitable for automating the parsing of a binary data stream represented as frames with common headers and returning the parsed data via an event.

This parser is designed as a write-only stream such that data can come from any source. This class is more specific than the in that it can automate the parsing of a particular protocol that is formatted as a series of frames that have a common method of identification. Automation of type creation occurs by loading implementations of common types that implement the interface. The common method of identification is handled by creating a class derived from the which primarily includes a TypeID property, but also should include any state information needed to parse a particular frame if necessary. Derived classes simply override the function in order to parse the from a provided binary image. Type of identifier used to distinguish output types. Type of the interface or class used to represent outputs.

Occurs when a data image is deserialized successfully to one of the output types that the data image represents.

is the object that was deserialized from the binary image.

Occurs when matching an output type for deserializing the data image could not be found.

is the ID of the output type that could not be found.

Occurs when more than one type has been defined that can deserialize the specified output type.

is the that defines a type ID that has already been defined.
is the ID of the output type that was defined more than once.

Creates a new instance of the class.

Gets the total number of parsed outputs that are currently queued for publication, if any.

Gets or sets a boolean value that indicates whether the frame image parser is currently enabled.

Gets current status of .

Releases the unmanaged resources used by the object and optionally releases the managed resources.

true to release both managed and unmanaged resources; false to release only unmanaged resources.

Start the data parser.

This overload loads public types from assemblies in the application binaries directory that implement the parser's output type.

Starts the data parser given the specified type implementations.

Output type implementations to establish for the parser.

Output type specific frame parsing algorithm.

Buffer containing data to parse. Offset index into buffer that represents where to start parsing. Maximum length of valid data from offset. The length of the data that was parsed.

Parses a common header instance that implements for the output type represented in the binary image.

Buffer containing data to parse. Offset index into buffer that represents where to start parsing. Maximum length of valid data from offset. The which includes a type ID for the to be parsed. Derived classes need to provide a common header instance (i.e., class that implements ) for the output types; this will primarily include an ID of the that the data image represents. This parsing is only for common header information, actual parsing will be handled by output type via its method. This header image should also be used to add needed complex state information about the output type being parsed if needed. If there is not enough buffer available to parse common header (as determined by ), return null. Also, if the protocol allows frame length to be determined at the time common header is being parsed and there is not enough buffer to parse the entire frame, it will be optimal to prevent further parsing by returning null.

Raises the event.

The object that was deserialized from binary image.

handler used to publish queued outputs.

Event args containing new output to publish.

Raises the event.

The ID of the output type that was not found.

Raises the event.

The that defines a type ID that has already been defined. The ID of the output type that was defined more than once.

Defines the common header of a frame image for a set of parsed types, consisting at least of a type ID.

Header implementations can extend this interface as necessary to accommodate protocol specific header images. Type of identifier used to distinguish output types.

Gets or sets the identifier used for identifying the to be parsed.

Gets or sets any additional state information that might be needed for parsing.

This interface represents a basic implementation of parsing functionality suitable for automating the parsing of a binary data stream represented as frames with common headers and returning the parsed data via an event.

Type of identifier used to distinguish output types. Type of the interface or class used to represent outputs.

Occurs when a data image is deserialized successfully to one of the output types that the data image represents.

is the object that was deserialized from the binary image.

Occurs when matching a output type for deserializing the data image could not be found.

is the ID of the output type that could not be found.

Specifies that this can produce or consume a frame of data represented as a binary image.

Related types of protocol data that occur as frames in a stream can implement this interface for automated parsing via the class. Type of the frame identifier.

Gets or sets current .

If used, this will need to be set before call to .

Gets the identifier that can be used for identifying the .

must be unique across all siblings implementing a common or interface. Output types implement this class so they have a consistently addressable identification property.

Gets flag that determines if frame image can queued for publication or should be processed immediately.

Some frames, e.g., a configuration or key frame, may be critical to processing of other frames. In this case, these types of frames should be published immediately so that subsequent frame parsing can have access to needed critical information.

Specifies that this can produce or consume a frame of data represented as a binary image that can be identified by its data source.

Related types of protocol data that occur as frames in a stream can implement this interface for automated parsing via the class. Type of identifier for the data source. Type of the frame identifier.

Gets or sets the data source identifier of the frame image.

Specifies that an object supports serialization via static operations using object-typed and methods.

This interface exists to allow classes to properly define the needed method signatures for using operations. However, as long as the and methods exist on a class with the proper signature, actual implementation of this interface is optional.

Gets flag that determines if type implementing is a list-type and supports its own list serialization handling, i.e., if automated list count and items serialization should be skipped by operations.

More commonly, if a type is assignable from an , it would be its element type that would implement and the list serialization would be handled automatically by operations. However, if a type is assignable from an and implements directly, then setting this property to true allows the list type to override default behavior and handle its own list serialization using the and methods.

Deserializes an object from a .

Source stream. New deserialized instance.

Serializes an object to a .

Target stream. Instance to serialize.

Specifies that an object supports serialization via static operations using strongly-typed and methods.

Type that implements stream serialization. This interface exists to allow classes to properly define the needed method signatures for using operations. However, as long as the and methods exist on a class with the proper signature, actual implementation of this interface is optional.

Deserializes an instance of type from a .

Source stream. New deserialized instance.

Serializes an of type to a .

Target stream. Instance to serialize.

This class defines a basic implementation of parsing functionality suitable for automating the parsing of multiple binary data streams, each represented as frames with common headers and returning the parsed data via an event.

This parser is designed as a write-only stream such that data can come from any source. This class is more specific than the in that it can automate the parsing of a particular protocol that is formatted as a series of frames that have a common method of identification. Automation of type creation occurs by loading implementations of common types that implement the interface. The common method of identification is handled by creating a class derived from the which primarily includes a TypeID property, but also should include any state information needed to parse a particular frame if necessary. Derived classes override the method in order to parse the from a provided binary image. Type of identifier for the data source. Type of identifier used to distinguish output types. Type of the interface or class used to represent outputs.

Represents a source identifiable buffer.

This class implements such that it will support automatic object pool handling, e.g., returning object to pool when disposed.

Defines the source identifier of the .

Defines the buffer which is identifiable by its associated .

Gets or sets enabled state of .

Gets or sets valid number of bytes within the .

This property will automatically initialize buffer. Set to zero to release buffer.

Occurs when a data image is deserialized successfully to one or more of the output types that the data image represents.

is the ID of the source for the data image.
is a list of objects deserialized from the data image.

Creates a new instance of the class.

Gets the total number of buffers that are currently queued for processing, if any.

Start the streaming data parser.

Starts the data parser given the specified type implementations.

Output type implementations to establish for the parser.

Queues a sequence of bytes, from the specified data source, onto the stream for parsing.

Identifier of the data source. An array of bytes to queue for parsing

Queues a sequence of bytes, from the specified data source, onto the stream for parsing.

Identifier of the data source. An array of bytes. This method copies count bytes from buffer to the queue. The zero-based byte offset in buffer at which to begin copying bytes to the current stream. The number of bytes to be written to the current stream. This method associates a buffer with its data source identifier.

Queues the object implementing the interface, from the specified data source, onto the stream for parsing.

Identifier of the data source. Object to be parsed that implements the interface. This method takes the binary image from and writes the buffer to the stream for parsing.

Clears the internal buffer of unparsed data received from the specified .

Identifier of the data source. This method can be used to ensure that partial data received from the is not kept in memory indefinitely.

Not implemented. Consumers should call the method instead to make sure data source ID gets tracked with data buffer.

This method should not be called directly. A .

Not implemented. Consumers should call the method instead to make sure data source ID gets tracked with data buffer.

This method should not be called directly. A array. An for the offset. An for the count.

Raises the event.

The object that was deserialized from binary image.

Raises the event.

Identifier for the data source. The objects that were deserialized from binary images from the data stream.

Raises the event.

Source buffer that contains output that failed to parse.

Contains classes used to simplify, standardize and automate any kind of IO based parsing operation.

Defines stream serialization operations for natives types or classes that expose ReadFrom and WriteTo methods. Instance and static options available. Arrays and lists of types are also supported, so long as base type is a native type or supports required serialization methods.

Target type for stream serialization. Deserialization Method Implementation Options:
ReadFrom Instance signature: void ReadFrom(Stream)
ReadFrom Static object-based signature: static object ReadFrom(Stream)
ReadFrom Static strongly-typed signature: static T ReadFrom(Stream)
Note that deserialization of type also supports a constructor that accepts a standalone parameter. Serialization Method Implementation Options:
WriteTo Instance signature: void WriteTo(Stream)
WriteTo Static object-based signature: static void WriteTo(Stream, object)
WriteTo Static strongly-typed signature: static void WriteTo(Stream, T)
Note that proper static method signatures can be defined for a class by implementing the or interface, implicitly or explicitly.

Gets read deserialization method for type .

Provides a type representing the encompassed elements when type is a list or array type, and element type cannot otherwise be ascertained, e.g., when element type is an . Set to true to skip automatic handling of list types. Read deserialization method.

Gets write serialization method for type .

Represents a template based token substitution parser that supports binary and advanced expressions.

As an example, this parser can use a templated expression of the form:


            {CompanyAcronym}_{DeviceAcronym}[?{SignalType.Source}=Phasor[-{SignalType.Suffix}{SignalIndex}]]:{Signal.Acronym}

then replace the tokens with actual values and properly evaluate the expressions. Example results could look like: GPA_SHELBY-PA1:IPHA and GPA_SHELBY:FREQ Parser also supports more complex C# style expressions using the "eval{}" function, e.g.:


            eval{'{CompanyAcronym}'.Substring(0,3)}_{DeviceAcronym}eval{'[?{SignalType.Source}=Phasor[-{SignalType.Suffix}]]'.Length}

Creates a new .

Creates a new with desired delimiters.

Character that identifies the beginning of a token. Character that identifies the end of a token. Character that identifies the beginning of an expression. Character that identifies the beginning of an expression. All delimiters must be unique -- or -- the symbol 'u' is reserved for encoding and cannot be used as a delimiter.

Gets or sets the templated expression to use.

Gets the reserved symbols - this includes all delimiters and expression operators.

The default reserved symbol list is: '\', '<', '>', '=', '!', '{', '}', '[', ']'.

Gets the character that identifies the beginning of a token.

Gets the character that identifies the end of a token.

Gets the character that identifies the start of an expression.

Gets the character that identifies the end of an expression.

Executes replacements using provided dictionary on the currently defined value and optionally evaluates any expressions.

Dictionary of substitutions. Dictionary keys are tokens to be replaced by the values. Determines if substitutions should be case-insensitive. Defaults to true. Determines if expressions should be evaluated. Defaults to true. Determines if reserved symbols in substitution values should be automatically escaped. Defaults to true. A string that was based on with tokens replaced and expressions evaluated. The default token start and end delimiters are { and } but can be overridden in constructor. All substitution tokens surrounded by and (e.g., {token}) will be immediately replaced with their string equivalents before further expression evaluation. As a result of the expression syntax <, >, =, and ! are reserved expressions symbols; , , and are reserved delimiter symbols. To embed any reserved symbol into the so that it appears in the evaluated result, escape the symbol by prefixing it with a backslash, e.g., \{. The default expression start and end delimiters are [ and ] but can be overridden in constructor. Expressions are represented in the form of [?expression[result]] and can be nested, e.g. ([?expression1[?expression2[result]]]). Expressions should not contain extraneous white space for proper evaluation. Only simple boolean comparison operations are allowed in expressions, e.g., A=B (or A==B), A!=B (or A<>B), A>B, A>=B, A<B and A<=B - nothing more. Any expression that fails to evaluate will be evaluated as FALSE. Note that if both left (A) and right (B) operands can be parsed as a numeric value then the expression will be numerically evaluated otherwise expression will be a culture-invariant string comparison. Nested expressions are evaluated as cumulative AND operators. There is no defined nesting limit. Advanced expressions can be parsed using the eval function, e.g., eval{1 + 2}. Eval function expression is delimited by the currently defined token delimiters, { and } by default. The evaluation engine deals with numbers and strings. The typing of numeric literals follow C# standards, suffixes such as d, f and m may be used to explicitly specify the numeric type. If no numeric suffix is provided, the default type of numeric literal is assumed to be . String literals should be specified using single quotes instead of double quotes, this includes substitution parameters, e.g., eval{'{DeviceAcronym}'.Length + 1}. Advanced evaluation expressions using the eval function are always parsed after common expressions. Eval functions cannot be nested. When is true and values in intentionally contain expressions to be evaluated, then should be set to false so that the reserved symbols in the values are not automatically escaped.

Defines a log message send by the System

The source of the log message. For Adapters this is the Adapter Name. For system messages it is an empty string.

The message content.

The Timestamp associated with the message.

The associates with this .