OpenSystemsDevelopment / qpdf

… `StreamDataProvider` management.

Implement default constructor, copy/move constructors, and assignment operators for `Stream`. Add overloads for initializing `Stream` with `QPDFObjectHandle`.

Replace `getParsedOffset()` with the new `offset()` method across `QPDFObjectHandle` and related classes for consistent offset handling. Simplify logic and remove redundant `getParsedOffset()` implementation.

Relocate `Pipe` functionality to `QPDF::Doc::Streams` for improved encapsulation of stream-related logic. Adjust all references to use the new placement.

…, and `Array` for improved clarity and consistency, and simplify `/Filter` and `/DecodeParms` handling.

… to use subscript operators, and simplify object access logic.

…string`, improving performance, simplifying stream data handling, and reducing dependency on `BufferInputSource`.

qpdf permits replacing standard stream filters with user provided filters.
#1457 incorrectly removed that option.

Introduced explicit checks for empty streams and refined filtering conditions for improved clarity and correctness.

Updated `SF_Crypt` class methods and destructor to use the `final` specifier for clarity and stricter override rules. Refactored `setDecodeParms` logic for better readability and accurate handling of dictionary keys. Other minor adjustments contribute to code maintainability and correctness.

Removed `expand_filter_name` method and integrated its functionality directly into `filter_factory` for improved clarity and maintainability. Consolidated filter handling logic to eliminate redundant operations and streamline code execution.

Replaced individual compression flags with a unified decode-level parameter for stream filtering. Introduced a helper function to handle filtering conditions, reducing redundancy and improving readability. Removed unused code and updated related tests to reflect these changes.

Stream provider logic has been streamlined by removing unnecessary variables and conditional checks. Adjusted handling of mismatched or missing stream lengths to improve code readability and maintainability.

Replaced shared_ptr with unique_ptr for pipeline management, reducing overhead and improving ownership semantics. Simplified conditional checks and modernized code to enhance readability by removing redundant variables and adjusting pointer usages. This refactor ensures better maintainability and minor performance gains in stream processing.

Refactored the handling of /DecodeParms by removing unnecessary vector creation and directly accessing elements in the decode array. This improves code clarity and maintains consistency with filters processing.

Simplified and reorganized logic for handling /DecodeParms in streams. Ensured proper initialization and updated filter checks for lossy and specialized compression, improving code clarity and maintainability.

Moved the conditional check for /DecodeParms inconsistency into the loop to ensure clearer handling when filters are non-empty. This improves code structure and maintains robustness for edge cases encountered in the wild.

Simplified the logic for handling /DecodeParms by using `as_array` and modernized code with `auto` and `emplace_back`. This improves code readability and aligns with modern C++ practices.

Removed the unnecessary `filterable` variable and streamlined the logic for handling stream decoding parameters. These changes eliminate redundant checks, improve readability, and ensure clarity in flow control for filter processing.

Replaced manual array handling with cleaner iteration using `as_array`. This improves code readability and ensures more robust processing of stream filter arrays.

Simplify and reorganize parsing logic to replace explicit filter name collection with direct filter creation. Added validation for unsupported filters, ensuring filters are cleared and errors returned when necessary. This improves code clarity and robustness.

Moved stream filter factory logic into `Members::filter_factory` for better encapsulation and maintainability. Removed redundant static filter factory map and improved error handling for invalid stream filter configurations.

Moved `expand_filter_name` calls to maintain uniformity and avoid redundant processing in filter handling. This ensures cleaner and more structured code without changing functionality.

Moved the filter abbreviation expansion logic from a static map to a new `expand_filter_name` method in `QPDF_Stream::Members`. This simplifies the code, improves maintainability, and consolidates the logic for easier testing and updates.

Only top-level XMP metadata is supposed to be left unencrypted. All
other metadata is not treated specially.

Move all stream-specific methods to new class qpdf::Stream

This improves indentation of long strings. This commit also fixes some
trailing whitespace in ChangeLog.

This reverts commit ff2a78f579ebdd06b417e34260a17dba06e71137, reversing
changes made to 8f54319f7a6514110f4b05cbbf1cb1c9fc8cb6a0.

1. Make class final
2. Pass og parameter by value
3. Properly initialize qpdf and og

Also, tweak QPDF::replaceObject to allow stream replacement without
violating the requirement that streams must always be indirect objects.

Also, remove QPDF::reserveStream as it does not do what the name implies
and having this as a separate methods does not aid code readability.

(Replacing the temporary implementation from the last commit.)

writeStreamJSON is a temporary implementation minimally adapted from
getStreamJSON.