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PavelBARABANOV
815325ccec
- [x] I have read and followed the [Contribution Guidelines](https://git.eden-emu.dev/eden-emu/eden/src/branch/master/CONTRIBUTING.md#code-contributions). - [x] I have read and followed the [AI Policy](https://git.eden-emu.dev/eden-emu/eden/src/branch/master/docs/policies/AI.md) - [x] I have read and followed the [Coding Guidelines](https://git.eden-emu.dev/eden-emu/eden/src/branch/master/docs/policies/Coding.md) to the best of my ability. ------------------- A new NSO compression method was introduced in Switch 22.0.0. This is a customized variant of zstd and is used when NSO flags have bit 7 set. Key characteristics: - ZSTD_MAGICNUMBER is set to 0x4349425A (b'ZBIC') instead of 0xFD2FB528 - ZSTD_LEGACY_SUPPORT is set to 0 - ZSTD_TRACE is set to 1, zstd version used is 1.5.7 (10507) - FSE_readNCount is replaced with a BIC (Binary Interpolative Coding) version which improves compression of entropy tables significantly Source: https://switchbrew.org/wiki/22.0.0 Implementation: - Detect ZBIC segments via NSO flag bit 7 (NsoFlags_UseZbicCompression) and/or ZBIC magic scan in nso.cpp - Fall back to LZ4 when ZBIC is not detected or returns unexpected size - Handle segment 0 alternate offset (0x100 vs 0x108) for both ZBIC and LZ4 References: - Atmosphère loader/strat zstd-zbic integration: https://github.com/Atmosphere-NX/Atmosphere/commit/082115187a0509cb6b8a757de639a4e4741b8712 - nxdumptool ZBIC segment compression support: https://github.com/DarkMatterCore/nxdumptool/commit/441e5c0904f29427987433be4eb057a2843d222a - STORM_SWITCH ZBIC implementation: https://github.com/ReiKatari/STORM_SWITCH/commit/1e09eb82b760aaf340b810031400991c0740c091 Tested with firmware 23.0.0 and ZBIC-compressed NSOs. Co-authored-by: xbzk <xbzk@eden-emu.dev> Reviewed-on: https://git.eden-emu.dev/eden-emu/eden/pulls/4482 Reviewed-by: CamilleLaVey <camillelavey99@gmail.com> Reviewed-by: lizzie <lizzie@eden-emu.dev> Reviewed-by: Maufeat <sahyno1996@gmail.com>