patterns/fbx: Fixed the fbx hexpat (#276)

* patterns: FBX - revised hexpat for fbx files but still broken

* patterns: FBX - implemented a workaround for the previously broken hexpat

* Disable ImHex-specific functions outside of ImHex

---------

Co-authored-by: Nik <werwolv98@gmail.com>

patterns/fbx.hexpat

@@ -4,18 +4,22 @@
 
 #pragma endian little
 
-import hex.dec;
+#ifdef __IMHEX__
+    import hex.dec;
+#endif
+
 import std.mem;
 import std.string;
 import std.sys;
+import type.magic;
 
 struct Array<E> {
     u32 arrayLength;
     u32 encoding;
     u32 compressedLength;
-
+    
     std::assert(encoding < 2, "Invalid array encoding!");
-
+    
     if (encoding == 0) {
         // Uncompressed
         E contents[arrayLength];
@@ -23,9 +27,12 @@ struct Array<E> {
         // Compressed (zlib)
         u128 pos = $;
         u8 compressedContents[compressedLength];
-        std::mem::Section contentsSection = std::mem::create_section(std::format("contentsSection @ {:#x}", pos));
+
-        hex::dec::zlib_decompress(compressedContents, contentsSection, 15);
+        #ifdef __IMHEX__
-        E contents[] @ 0x00 in contentsSection;
+            std::mem::Section contentsSection = std::mem::create_section(std::format("contentsSection @ {:#x}", pos));
+            hex::dec::zlib_decompress(compressedContents, contentsSection, 15);
+            E contents[] @ 0x00 in contentsSection;
+        #endif
     }
 };
 
@@ -50,7 +57,7 @@ enum PropertyTypeCode : char {
 
 struct PropertyRecord {
     PropertyTypeCode typeCode;
-
+    
     match (typeCode) {
         (PropertyTypeCode::BYTE): s8 data;
         (PropertyTypeCode::SHORT): s16 data;
@@ -78,78 +85,148 @@ struct PropertyRecord {
     }
 };
 
-struct NodeRecord<T> {
+using NodeRecord32B;
-    T endOffset;
-    T numProperties;
-    T propertyListLen;
-    u8 nameLen;
 
+struct NodeRecord32A {
+    u32 endOffset;
+    u32 numProperties;
+    u32 propertyListLen;
+    u8 nameLen;
+    
     // Detect sentinel record which marks the end of a list of node records
-    if (endOffset == 0
+    if (endOffset == 0 
-        && numProperties == 0
+        && numProperties == 0 
-        && propertyListLen == 0
+        && propertyListLen == 0 
         && nameLen == 0) {
         break;
     }
-
+    
     char name[nameLen];
     auto posBeforePropertyRecords = $;
     auto posAfterPropertyRecords = posBeforePropertyRecords + propertyListLen;
     PropertyRecord propertyRecords[numProperties];
-    $ = posAfterPropertyRecords;
+    std::assert($ == posAfterPropertyRecords, std::format("Invalid size of propertyRecords @ {:#x} !", posBeforePropertyRecords));
-    NodeRecord<T> nestedList[while(true)];
+    NodeRecord32B nestedList[while($ < endOffset)];
-    $ = endOffset;
+    std::assert($ == endOffset, std::format("Invalid size of nestedList @ {:#x} !", posAfterPropertyRecords));
+};
+
+struct NodeRecord32B {
+    u32 endOffset;
+    u32 numProperties;
+    u32 propertyListLen;
+    u8 nameLen;
+    
+    // Detect sentinel record which marks the end of a list of node records
+    if (endOffset == 0 
+        && numProperties == 0 
+        && propertyListLen == 0 
+        && nameLen == 0) {
+        break;
+    }
+    
+    char name[nameLen];
+    auto posBeforePropertyRecords = $;
+    auto posAfterPropertyRecords = posBeforePropertyRecords + propertyListLen;
+    PropertyRecord propertyRecords[numProperties];
+    std::assert($ == posAfterPropertyRecords, std::format("Invalid size of propertyRecords @ {:#x} !", posBeforePropertyRecords));
+    NodeRecord32A nestedList[while($ < endOffset)];
+    std::assert($ == endOffset, std::format("Invalid size of nestedList @ {:#x} !", posAfterPropertyRecords));
+};
+
+using NodeRecord64B;
+
+struct NodeRecord64A {
+    u64 endOffset;
+    u64 numProperties;
+    u64 propertyListLen;
+    u8 nameLen;
+    
+    // Detect sentinel record which marks the end of a list of node records
+    if (endOffset == 0 
+        && numProperties == 0 
+        && propertyListLen == 0 
+        && nameLen == 0) {
+        break;
+    }
+    
+    char name[nameLen];
+    auto posBeforePropertyRecords = $;
+    auto posAfterPropertyRecords = posBeforePropertyRecords + propertyListLen;
+    PropertyRecord propertyRecords[numProperties];
+    std::assert($ == posAfterPropertyRecords, std::format("Invalid size of propertyRecords @ {:#x} !", posBeforePropertyRecords));
+    NodeRecord64B nestedList[while($ < endOffset)];
+    std::assert($ == endOffset, std::format("Invalid size of nestedList @ {:#x} !", posAfterPropertyRecords));
+};
+
+struct NodeRecord64B {
+    u64 endOffset;
+    u64 numProperties;
+    u64 propertyListLen;
+    u8 nameLen;
+    
+    // Detect sentinel record which marks the end of a list of node records
+    if (endOffset == 0 
+        && numProperties == 0 
+        && propertyListLen == 0 
+        && nameLen == 0) {
+        break;
+    }
+    
+    char name[nameLen];
+    auto posBeforePropertyRecords = $;
+    auto posAfterPropertyRecords = posBeforePropertyRecords + propertyListLen;
+    PropertyRecord propertyRecords[numProperties];
+    std::assert($ == posAfterPropertyRecords, std::format("Invalid size of propertyRecords @ {:#x} !", posBeforePropertyRecords));
+    NodeRecord64A nestedList[while($ < endOffset)];
+    std::assert($ == endOffset, std::format("Invalid size of nestedList @ {:#x} !", posAfterPropertyRecords));
 };
 
 fn assertZero (auto array, u128 size, auto message) {
     bool nonzeroPadding = false;
-
+    
     for (u8 i = 0, i < size, i = i + 1) {
         if (array[i] != 0) {
             nonzeroPadding = true;
         }
     }
-
+    
     std::assert_warn(!nonzeroPadding, message);
 };
 
 struct Footer{
-    char footerId[16];
+    type::Magic<"\xFA\xBC\xAB\x09\xD0\xC8\xD4\x66\xB1\x76\xFB\x83\x1C\xF7\x26\x7E"> footerId;
-    std::assert_warn(footerId == "\xFA\xBC\xAB\x09\xD0\xC8\xD4\x66\xB1\x76\xFB\x83\x1C\xF7\x26\x7E", "Invalid footerId!");
     char zeroes[4];
     assertZero(zeroes, 4, "Found non-zero values in footer after footerId!");
     u128 ofs = $;
     u8 alignmentPaddingSize = ((ofs + 15) & ~15) - ofs;
-
+    
     if (alignmentPaddingSize == 0) {
         alignmentPaddingSize = 16;
     }
-
+    
     char alignmentPadding[alignmentPaddingSize];
     assertZero(alignmentPadding, alignmentPaddingSize, "Found non-zero bytes in alignmentPadding!");
     u32 version;
     char staticPadding[120];
     assertZero(staticPadding, 120, "Found non-zero bytes in staticPadding!");
-    char footerMagic[16];
+    type::Magic<"\xF8\x5A\x8C\x6A\xDE\xF5\xD9\x7E\xEC\xE9\x0C\xE3\x75\x8F\x29\x0B"> footerMagic;
-    std::assert_warn(footerMagic == "\xF8\x5A\x8C\x6A\xDE\xF5\xD9\x7E\xEC\xE9\x0C\xE3\x75\x8F\x29\x0B", "Invalid footerMagic!");
 };
 
 
 struct Header {
-    char magic[23];
+    type::Magic<"Kaydara FBX Binary  \x00\x1A\x00"> magic;
-    std::assert(magic == "Kaydara FBX Binary  \x00\x1A\x00", "File is not a valid FBX!");
     u32 version;
 };
 
 struct FBX {
     Header header;
-
+    
     if  (header.version < 7500) {
-        NodeRecord<u32> rootRecords[while(true)];
+        NodeRecord32A rootRecords[while(true)];
     } else {
-        NodeRecord<u64> rootRecords[while(true)];
+        NodeRecord64A rootRecords[while(true)];
     }
-
+    
     Footer footer;
     std::assert_warn(header.version == footer.version, "Version numbers in header and footer do not match!");
 };