ksys: Decompile ByamlUtil

And fix some declarations in Byaml.h

src/KingSystem/Utils/Byaml.h

@@ -33,7 +33,7 @@ enum class ByamlType {
 
 class ByamlIter {
 public:
-    ByamlIter() = default;
+    ByamlIter();
     explicit ByamlIter(const u8* data);
     ByamlIter(const u8* data, const u8* root_node);
     ByamlIter(const ByamlIter& other);

src/KingSystem/Utils/ByamlUtil.cpp

@@ -0,0 +1,43 @@
+#include "KingSystem/Utils/Byaml.h"
+
+namespace al {
+
+bool tryGetByamlS32(s32* value, const ByamlIter& iter, const char* key) {
+    return iter.tryGetIntByKey(value, key);
+}
+
+bool tryGetByamlU32(u32* value, const ByamlIter& iter, const char* key) {
+    s32 v{};
+    bool ret = iter.tryGetIntByKey(&v, key);
+    if (ret)
+        *value = v;
+    return ret;
+}
+
+bool tryGetByamlF32(f32* value, const ByamlIter& iter, const char* key) {
+    f32 v{};
+    bool ret = iter.tryGetFloatByKey(&v, key);
+    if (!ret)
+        return false;
+    *value = v;
+    return true;
+}
+
+bool tryGetByamlV3f(sead::Vector3f* value, const ByamlIter& iter, const char* key) {
+    f32 x, y, z;
+    ByamlIter vec_iter;
+    if (!iter.tryGetIterByKey(&vec_iter, key))
+        return false;
+
+    x = 0;
+    bool ok = vec_iter.tryGetFloatByKey(&x, "X");
+    y = 0;
+    ok |= vec_iter.tryGetFloatByKey(&y, "Y");
+    z = 0;
+    ok |= vec_iter.tryGetFloatByKey(&z, "Z");
+
+    *value = {x, y, z};
+    return ok;
+}
+
+}  // namespace al