ksys/res: Implement OffsetReadFileDevice

3 files changed, 137 insertions, 0 deletions

diff --git a/src/KingSystem/Resource/CMakeLists.txt b/src/KingSystem/Resource/CMakeLists.txt
index 0098d6c6..75aaab56 100644
--- a/src/KingSystem/Resource/CMakeLists.txt
+++ b/src/KingSystem/Resource/CMakeLists.txt
@@ -90,6 +90,8 @@ target_sources(uking PRIVATE
   resHandle.h
   resLoadRequest.cpp
   resLoadRequest.h
+  resOffsetReadFileDevice.cpp
+  resOffsetReadFileDevice.h
 
   resResource.cpp
   resResource.h
diff --git a/src/KingSystem/Resource/resOffsetReadFileDevice.cpp b/src/KingSystem/Resource/resOffsetReadFileDevice.cpp
new file mode 100644
index 00000000..5bc3f9ac
--- /dev/null
+++ b/src/KingSystem/Resource/resOffsetReadFileDevice.cpp
@@ -0,0 +1,94 @@
+#include "KingSystem/Resource/resOffsetReadFileDevice.h"
+#include <heap/seadHeapMgr.h>
+#include <math/seadMathCalcCommon.h>
+#include "KingSystem/Resource/resSystem.h"
+
+namespace ksys::res {
+
+OffsetReadFileDevice::OffsetReadFileDevice(sead::Heap* heap) : sead::MainFileDevice(heap) {
+    resetOffsetRead();
+}
+
+void OffsetReadFileDevice::setFileDevice(sead::FileDevice* device) {
+    OffsetRead::setFileDevice(device);
+}
+
+/// This is a modified version of `sead::FileDevice::doLoad_`.
+u8* OffsetReadFileDevice::doLoad_(sead::FileDevice::LoadArg& arg) {
+    if (arg.buffer && arg.buffer_size == 0) {
+        stubbedLogFunction();
+        return nullptr;
+    }
+
+    sead::FileDevice* device = mOffsetReadFileDevice;
+    if (!device)
+        device = this;
+
+    sead::FileHandle handle;
+    if (!device->tryOpen(&handle, arg.path, FileDevice::cFileOpenFlag_ReadOnly, arg.div_size))
+        return nullptr;
+
+    u32 bytesToRead = arg.buffer_size;
+    if (!arg.buffer || arg.check_read_entire_file) {
+        u32 fileSize = 0;
+        if (!device->tryGetFileSize(&fileSize, &handle))
+            return nullptr;
+
+        if (fileSize == 0) {
+            stubbedLogFunction();
+            return nullptr;
+        }
+
+        if (bytesToRead != 0) {
+            if (bytesToRead < fileSize) {
+                stubbedLogFunction();
+                return nullptr;
+            }
+        } else {
+            bytesToRead = mOffsetReadOffset + sead::Mathi::roundUpPow2Positive(
+                                                  fileSize, FileDevice::cBufferMinAlignment);
+        }
+    }
+
+    u8* buf = arg.buffer;
+    bool allocated = false;
+
+    if (buf == nullptr) {
+        const s32 sign = (arg.alignment < 0) ? -1 : 1;
+        s32 alignment = sead::abs(arg.alignment);
+        alignment = sign * ((alignment < cBufferMinAlignment) ? cBufferMinAlignment : alignment);
+
+        sead::Heap* heap = arg.heap;
+        if (!heap)
+            heap = sead::HeapMgr::instance()->getCurrentHeap();
+
+        void* raw_buf = heap->tryAlloc(bytesToRead, alignment);
+        if (!raw_buf)
+            return nullptr;
+
+        buf = new (raw_buf) u8[bytesToRead];
+        allocated = true;
+    }
+
+    u32 bytesRead = 0;
+    if (!device->tryRead(&bytesRead, &handle, buf + mOffsetReadOffset,
+                         bytesToRead - mOffsetReadOffset)) {
+        if (allocated)
+            delete[] buf;
+        return nullptr;
+    }
+
+    if (!device->tryClose(&handle)) {
+        if (allocated)
+            delete[] buf;
+        return nullptr;
+    }
+
+    arg.read_size = bytesRead;
+    arg.roundup_size = bytesToRead;
+    arg.need_unload = allocated;
+
+    return buf;
+}
+
+}  // namespace ksys::res
diff --git a/src/KingSystem/Resource/resOffsetReadFileDevice.h b/src/KingSystem/Resource/resOffsetReadFileDevice.h
new file mode 100644
index 00000000..93c4800f
--- /dev/null
+++ b/src/KingSystem/Resource/resOffsetReadFileDevice.h
@@ -0,0 +1,41 @@
+#pragma once
+
+#include <filedevice/seadMainFileDevice.h>
+#include "KingSystem/Utils/Types.h"
+
+namespace ksys::res {
+
+class OffsetRead {
+public:
+    OffsetRead() { resetOffsetRead(); }
+    virtual ~OffsetRead() = default;
+
+    void setReadOffset(u32 offset) { mOffsetReadOffset = offset; }
+    void setFileDevice(sead::FileDevice* device) { mOffsetReadFileDevice = device; }
+
+    void resetOffsetRead() {
+        mOffsetReadOffset = 0;
+        mOffsetReadFileDevice = nullptr;
+    }
+
+protected:
+    u32 mOffsetReadOffset;
+    sead::FileDevice* mOffsetReadFileDevice;
+};
+KSYS_CHECK_SIZE_NX150(OffsetRead, 0x18);
+
+class OffsetReadFileDevice : public sead::MainFileDevice, public OffsetRead {
+    SEAD_RTTI_OVERRIDE(OffsetReadFileDevice, sead::MainFileDevice)
+public:
+    explicit OffsetReadFileDevice(sead::Heap* heap);
+    ~OffsetReadFileDevice() override = default;
+
+    void setReadOffset(u32 offset) { OffsetRead::setReadOffset(offset); }
+    void setFileDevice(sead::FileDevice* device);
+
+protected:
+    u8* doLoad_(LoadArg& arg) override;
+};
+KSYS_CHECK_SIZE_NX150(OffsetReadFileDevice, 0xa0);
+
+}  // namespace ksys::res