[core] Support block-compressed NSZ and XCZ (#4552)

- [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.

-------------------
- Add NCZBLOCK (nsz -B / .xcz) reader: each read decodes only the covered blocks and re-encrypts CTR sections, no disk output.
- Allow installing solid .nsz to NAND via DecompressNCZForInstall (lazy, incremental decode with frontier, O(n) instead of O(n^2)).
- Accept BKTR updates with thousands of sections (MaxSectionCount = 0x10000).
- Wire .nsz/.xcz into loader, registered cache, scanner, and NAND install (content_manager.h), and reject solid NCZ from the game list.
- Bump the pinned zstd to 33618c8 in cpmfile.json, which includes the upstream AArch64 revert ([33618c89](https://github.com/facebook/zstd/commit/33618c89e511637f8a6ef955b3501766d71feb53)) for a ZSTD_decodeSequence branch optimization that could corrupt data on ARM64; without it, solid NCZ decoding on Android fails with "Data corruption detected".

NCZ format and CTR counter semantics follow the reference nsz tool and its
Rust port:
- https://github.com/nicoboss/nsz (Decompressor.py, BlockDecompressorReader.py)
- https://docs.rs/nsz-rs/0.3.0/src/nsz_rs/decompress.rs.html

The last-block edge case (decompressed size is an exact multiple of block
size) is handled as described in https://github.com/nicoboss/nsz/issues/210

Reviewed-on: https://git.eden-emu.dev/eden-emu/eden/pulls/4552
Reviewed-by: CamilleLaVey <camillelavey99@gmail.com>
Reviewed-by: Shinmegumi <shinmegumi@eden-emu.dev>

3 files changed, 52 insertions, 9 deletions

diff --git a/src/core/loader/loader.cpp b/src/core/loader/loader.cpp
index 90e23ccc11..92e2e2f602 100644
--- a/src/core/loader/loader.cpp
+++ b/src/core/loader/loader.cpp
@@ -82,23 +82,27 @@ std::shared_ptr<FileSys::NSP> OpenContainerAsNsp(FileSys::VirtualFile file, File
         return nullptr;
     }
 
-    if (type == FileType::NSP) {
+    if (type == FileType::NSP || type == FileType::NSZ) {
         auto nsp = std::make_shared<FileSys::NSP>(file, program_id, program_index);
         return nsp->GetStatus() == ResultStatus::Success ? nsp : nullptr;
     }
 
-    if (type == FileType::XCI) {
+    if (type == FileType::XCI || type == FileType::XCZ) {
         FileSys::XCI xci{file, program_id, program_index};
-        if (xci.GetStatus() != ResultStatus::Success) {
-            return nullptr;
+        if (xci.GetStatus() == ResultStatus::Success) {
+            auto secure_nsp = xci.GetSecurePartitionNSP();
+            if (secure_nsp != nullptr && secure_nsp->GetStatus() == ResultStatus::Success) {
+                return secure_nsp;
+            }
         }
 
-        auto secure_nsp = xci.GetSecurePartitionNSP();
-        if (secure_nsp == nullptr || secure_nsp->GetStatus() != ResultStatus::Success) {
-            return nullptr;
+        // PFS0-shaped .xcz (NSZ-style container) does not parse as XCI; fall back to NSP.
+        if (type == FileType::XCZ) {
+            auto nsp = std::make_shared<FileSys::NSP>(file, program_id, program_index);
+            return nsp->GetStatus() == ResultStatus::Success ? nsp : nullptr;
         }
 
-        return secure_nsp;
+        return nullptr;
     }
 
     return nullptr;
@@ -144,7 +148,8 @@ FileType IdentifyFile(FileSys::VirtualFile file) {
 }
 
 bool IsContainerType(FileType type) {
-    return type == FileType::NSP || type == FileType::XCI;
+    return type == FileType::NSP || type == FileType::NSZ || type == FileType::XCI ||
+           type == FileType::XCZ;
 }
 
 bool IsBootableGameContainer(FileSys::VirtualFile file, FileType type, u64 program_id,
@@ -180,8 +185,12 @@ FileType GuessFromFilename(const std::string& name) {
         return FileType::NCA;
     else if (extension == "xci")
         return FileType::XCI;
+    else if (extension == "xcz")
+        return FileType::XCZ;
     else if (extension == "nsp")
         return FileType::NSP;
+    else if (extension == "nsz")
+        return FileType::NSZ;
     else if (extension == "kip")
         return FileType::KIP;
     return FileType::Unknown;
@@ -197,10 +206,14 @@ std::string GetFileTypeString(FileType type) {
         return "NCA";
     case FileType::XCI:
         return "XCI";
+    case FileType::XCZ:
+        return "XCZ";
     case FileType::NAX:
         return "NAX";
     case FileType::NSP:
         return "NSP";
+    case FileType::NSZ:
+        return "NSZ";
     case FileType::KIP:
         return "KIP";
     case FileType::DeconstructedRomDirectory:
@@ -326,12 +339,29 @@ static std::unique_ptr<AppLoader> GetFileLoader(Core::System& system, FileSys::V
                                                system.GetContentProvider(), program_id,
                                                program_index);
 
+    // NCZ-compressed XCI container. XCI-shaped .xcz goes to the XCI loader, while
+    // PFS0-shaped (NSZ-style) .xcz containers fall back to the NSP loader.
+    case FileType::XCZ: {
+        FileSys::XCI probe{file, program_id, program_index};
+        if (probe.GetStatus() == ResultStatus::Success &&
+            probe.GetSecurePartitionNSP() != nullptr) {
+            return std::make_unique<AppLoader_XCI>(std::move(file),
+                                                   system.GetFileSystemController(),
+                                                   system.GetContentProvider(), program_id,
+                                                   program_index);
+        }
+        return std::make_unique<AppLoader_NSP>(std::move(file), system.GetFileSystemController(),
+                                               system.GetContentProvider(), program_id,
+                                               program_index);
+    }
+
     // NX NAX (NintendoAesXts) file format.
     case FileType::NAX:
         return std::make_unique<AppLoader_NAX>(std::move(file));
 
     // NX NSP (Nintendo Submission Package) file format
     case FileType::NSP:
+    case FileType::NSZ:
         return std::make_unique<AppLoader_NSP>(std::move(file), system.GetFileSystemController(),
                                                system.GetContentProvider(), program_id,
                                                program_index);
diff --git a/src/core/loader/loader.h b/src/core/loader/loader.h
index 95ce638da0..d3c0230cb0 100644
--- a/src/core/loader/loader.h
+++ b/src/core/loader/loader.h
@@ -42,7 +42,9 @@ enum class FileType {
     NRO,
     NCA,
     NSP,
+    NSZ,
     XCI,
+    XCZ,
     NAX,
     KIP,
     DeconstructedRomDirectory,
diff --git a/src/core/loader/nsp.cpp b/src/core/loader/nsp.cpp
index cfc908b4ef..8b2c79394d 100644
--- a/src/core/loader/nsp.cpp
+++ b/src/core/loader/nsp.cpp
@@ -56,6 +56,17 @@ AppLoader_NSP::AppLoader_NSP(FileSys::VirtualFile file_,
 AppLoader_NSP::~AppLoader_NSP() = default;
 
 FileType AppLoader_NSP::IdentifyType(const FileSys::VirtualFile& nsp_file) {
+    // .nsz is NSP-compatible; return NSZ so the game list shows the right type.
+    if (nsp_file->GetName().ends_with(".nsz")) {
+        return FileType::NSZ;
+    }
+
+    // PFS0-shaped .xcz containers are handled by this loader too; report XCZ so the game
+    // list does not show them as NSP. XCI-shaped .xcz is identified by AppLoader_XCI.
+    if (nsp_file->GetName().ends_with(".xcz")) {
+        return FileType::XCZ;
+    }
+
     const FileSys::NSP nsp(nsp_file);
 
     if (nsp.GetStatus() != ResultStatus::Success) {