shader: Initial recompiler work

src/shader_recompiler/file_environment.cpp

@@ -0,0 +1,42 @@
+#include <cstdio>
+
+#include "exception.h"
+#include "file_environment.h"
+
+namespace Shader {
+
+FileEnvironment::FileEnvironment(const char* path) {
+    std::FILE* const file{std::fopen(path, "rb")};
+    if (!file) {
+        throw RuntimeError("Failed to open file='{}'", path);
+    }
+    std::fseek(file, 0, SEEK_END);
+    const long size{std::ftell(file)};
+    std::rewind(file);
+    if (size % 8 != 0) {
+        std::fclose(file);
+        throw RuntimeError("File size={} is not aligned to 8", size);
+    }
+    // TODO: Use a unique_ptr to avoid zero-initializing this
+    const size_t num_inst{static_cast<size_t>(size) / 8};
+    data.resize(num_inst);
+    if (std::fread(data.data(), 8, num_inst, file) != num_inst) {
+        std::fclose(file);
+        throw RuntimeError("Failed to read instructions={} from file='{}'", num_inst, path);
+    }
+    std::fclose(file);
+}
+
+FileEnvironment::~FileEnvironment() = default;
+
+u64 FileEnvironment::ReadInstruction(u32 offset) const {
+    if (offset % 8 != 0) {
+        throw InvalidArgument("offset={} is not aligned to 8", offset);
+    }
+    if (offset / 8 >= static_cast<u32>(data.size())) {
+        throw InvalidArgument("offset={} is out of bounds", offset);
+    }
+    return data[offset / 8];
+}
+
+} // namespace Shader