Add REPL set_offset and search_offset commands

[YSaxon]

Motivation

• Provide REPL primitives to set library offsets directly and to discover offsets by searching a library's readable memory, complementing the existing calculate_offset workflow.
• Make it easier to compute and store offsets for libraries across platforms by searching process memory for a known byte sequence and validating uniqueness before storing the offset.

Description

• Added parseSetOffset to implement set_offset <library> <offset> which stores an offset via the existing storeOffsetForLibLoadedAtAddress mechanism.
• Added parseSearchOffset to implement search_offset [<variable>] <library> <bytestring> <address> which parses bytestring (plain text or 0x.. hex), locates readable memory ranges for the target library, searches for the pattern, hex-dumps context around the first (and second) matches, verifies uniqueness, computes address_in_memory - address_provided, stores the offset and optionally stores it in the given variable.
• Implemented helpers in src/main.c: parseByteString, MemoryRangeList management, collectReadableLibraryRanges with platform-specific memory discovery (/proc/self/maps for Linux, VirtualQuery for Windows, Mach VM region walking for macOS), findSubsequence, and dumpMatchContext.
• Updated REPL help text and the REPL command dispatcher to register set_offset and search_offset commands.

Testing

• Built the project with cmake -S . -B build && cmake --build build -j4, which completed successfully (compile succeeded, warnings only).
• Ran unit and integration tests via ctest --test-dir build --output-on-failure and all tests passed (156/156 tests passed).

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[chatgpt-codex-connector]

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[chatgpt-codex-connector]

Restrict macOS range collection to the requested library

In the __APPLE__ branch, every readable VM region is appended without checking whether it belongs to the requested library, so search_offset can match bytes from unrelated images and either compute a wrong offset or fail as "multiple times" even when the target library has a unique match. This affects macOS runs whenever the pattern exists outside the requested module.

Useful? React with 👍 / 👎.

[chatgpt-codex-connector]

Normalize ARM Thumb addresses before offset subtraction

parseSearchOffset subtracts providedAddress directly, but unlike parseCalculateOffset it never clears the Thumb bit on ARM. When the user supplies a function/symbol pointer in Thumb mode (LSB set), the stored offset becomes off by one byte, which breaks later address reconstruction for relative calls on ARM targets.

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