patterns: Add .bgcode file (#222)

Support for binary G-code files, used by 3d printers

patterns/bgcode.hexpat

@@ -0,0 +1,80 @@
+#pragma author Shadlock0133 (aka Aurora)
+#pragma description Binary G-Code from Prusa
+
+#include <type/magic.pat>
+#include <std/mem.pat>
+
+enum ChecksumType : u16 {
+    None,
+    CRC32,
+};
+
+enum BlockType : u16 {
+    FileMetadata,
+    GCode,
+    SlicerMetadata,
+    PrinterMetadata,
+    PrintMetadata,
+    Thumbnail,
+};
+
+enum Compression : u16 {
+    None,
+    Deflate,
+    Heatshrink11_4,
+    Heatshrink12_4,
+};
+
+enum Encoding : u16 {
+    Ini,
+};
+
+enum ImageFormat : u16 {
+    Png,
+    Jpg,
+    Qoi,
+};
+
+struct Header {
+    type::Magic<"GCDE"> magic;
+    u32 version;
+    ChecksumType checksum_type;
+};
+
+Header header @ 0;
+std::assert(header.version == 1, "only version 1 supported");
+    
+struct Block {
+    BlockType type;
+    Compression compression;
+    u32 uncompressed_size;
+    auto size = uncompressed_size;
+    if (compression != Compression::None) {
+        u32 compressed_size;
+        size = compressed_size;
+    }
+    match (type) {
+        (BlockType::FileMetadata
+        | BlockType::PrinterMetadata
+        | BlockType::PrintMetadata
+        | BlockType::SlicerMetadata): {
+            Encoding encoding;
+        }
+        (BlockType::Thumbnail): {
+            ImageFormat image_format;
+            u16 width;
+            u16 height;
+        }
+        (BlockType::GCode): {
+            u16;
+        }
+        (_): { std::assert(false, "unknown type"); }
+    }
+    u8 data[size];
+    match (header.checksum_type) {
+        (ChecksumType::None): {}
+        (ChecksumType::CRC32): { u32 checksum; }
+    }
+};
+
+Block blocks[while(!std::mem::eof())] @ $;