patterns: Add Windows animated cursor (#242)

* patterns: Add Windows animated cursor

* Added readme entry

* Added mime type to readme

---------

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

README.md

@@ -26,6 +26,7 @@ Everything will immediately show up in ImHex's Content Store and gets bundled wi
 | 3DS | | [`patterns/3ds.hexpat`](patterns/3ds.hexpat) | Autodesk 3DS Max Model file |
 | 7Z | | [`patterns/7z.hexpat`](patterns/7z.hexpat) | 7z File Format |
 | AFE2 | | [`patterns/afe2.hexpat`](patterns/afe2.hexpat) | Nintendo Switch Atmosphère CFW Fatal Error log |
+| ANI | `application/x-navi-animation` | [`patterns/ani.hexpat`](patterns/ani.hexpat) | Windows Animated Cursor file |
 | AR | `application/x-archive` | [`patterns/ar.hexpat`](patterns/ar.hexpat) | Static library archive files |
 | ARIA2 | | [`patterns/aria2.hexpat`](patterns/aria2.hexpat) | ARIA2 Download Manager Control files |
 | ARM VTOR | | [`patterns/arm_cm_vtor.hexpat`](patterns/arm_cm_vtor.hexpat) | ARM Cortex M Vector Table Layout |

patterns/ani.hexpat

@@ -0,0 +1,66 @@
+#pragma description Windows animated cursor
+#pragma MIME application/x-navi-animation
+#pragma endian little
+
+import std.io;
+import std.mem;
+
+bitfield HeaderFlags {
+    icon : 1;
+    sequence : 1;
+    padding: 30;
+};
+
+struct anih {
+    u32 struct_size;
+    u32 stored_frames;
+    u32 animation_steps;
+    u32 w;
+    u32 h;
+    u32 bits;
+    u32 planes;
+    u32 default_jiffies;
+    HeaderFlags flags;
+};
+
+struct rate {
+    u32 jiffies[parent.size / 4];
+};
+
+struct seq {
+    u32 index[parent.size / 4];
+};
+
+struct RiffChunk {
+    char signature[4];
+    u32 size;
+    if (signature == "RIFF" || signature == "LIST") {
+        char type[4];
+        RiffChunk chunks[while($ - addressof(type) < size)];
+    } else if (signature[0] == 'I' && parent.type == "INFO") {
+        char info[size];
+    } else if (signature == "anih") {
+        anih anih [[inline]];
+    } else if (signature == "rate") {
+        rate rate [[inline]];
+    } else if (signature == "seq ") {
+        seq seq [[inline]];
+    } else {
+        std::mem::Bytes<size> data;
+    }
+    padding[size % 2];
+} [[format_read("read_chunk")]];
+
+fn read_chunk(RiffChunk chunk) {
+    if (chunk.signature == "RIFF" || chunk.signature == "LIST") {
+        return std::format("{}<{}> ({})", chunk.signature, chunk.type, chunk.size);
+    } else {
+        str ret = std::format("{} ({})", chunk.signature, chunk.size);
+        try {
+            ret += std::format(" \"{}\"", chunk.info);
+        } catch {}
+        return ret;
+    }
+};
+
+RiffChunk riff @ 0;