The OutOfDataException class provides a specialized exception type for scenarios where an operation attempting to read or consume data from a sequential data source (e.g., a stream, buffer, or parser) has exceeded the available data. It extends System.Exception to include contextual information—the Index at which the shortage occurred—enabling callers to pinpoint the location of the failure and implement recovery or error-reporting logic accordingly.
2. Public Interface
OutOfDataException(string message, long index)
Constructor. Initializes a new instance of the OutOfDataException class with a specified error message and the zero-based index in the data source where the shortage occurred. The index parameter is stored in the Index property and is immutable after construction.
long Index { get; }
Read-only property exposing the zero-based index (e.g., byte offset, element position, or token index) in the underlying data source where the exception was thrown. This value is set at construction and cannot be modified.
3. Invariants
Index is non-negative and represents a position beyond the last valid data element (i.e., Index >= DataLength).
Index is set exactly once during construction and remains constant for the lifetime of the exception instance.
The exception message (Message inherited from Exception) must clearly describe the nature of the data shortage (e.g., “Unexpected end of input at index 42”).
4. Dependencies
Depends on: System.Exception (via System namespace).
Used by: Likely consumed by data-parsing, deserialization, or streaming components within the DTS.Common namespace (e.g., DTS.Common.Core, DTS.Common.IO)—though no direct usages are visible in this file, the exception’s design implies integration with data-reading logic.
No external dependencies beyond the base .NET runtime.
5. Gotchas
The Index property uses a zero-based convention, but callers must verify whether the underlying data source uses byte offsets, character positions, or element indices (e.g., in a token stream) to avoid misinterpretation.
The exception does not include the total data length; callers must track capacity separately if needed for context.
The Index is long, suggesting support for large data sources (e.g., >2GB), but callers should ensure consistency with the data source’s indexing scheme (e.g., int-based APIs may require casting).
No additional context (e.g., source name, buffer snapshot) is stored—only the index and message—limiting diagnostic depth without external correlation.
