patterns/dsstore: Added .DS_Store pattern (#90)

* Initial format for Buddy Allocator structures in `.DS_Store` files

* Add list of entries for files in `.DS_Store`

* Add root block, offsets, toc and free lists structures

* Add parsing of block data

* Document `.DS_Store` pattern and add test file

patterns/dsstore.hexpat

@@ -0,0 +1,113 @@
+// Apple macOS .DS_Store format
+#pragma endian big
+#include <std/io.pat>
+
+struct RecordEntry {
+  u32 length;
+  char16 filename[length];
+  
+  char id[4];
+  // either blob or length
+  char type[4];
+  
+  if (type == "blob") {
+    u32 blobCount;
+    u8 blobData[blobCount];
+  }
+  else if (type == "long") {
+    u32 value;
+  }
+  else if (type == "shor") {
+    u32 value;
+  }
+  else if (type == "bool") {
+    u8 value;
+  }
+};
+
+struct TreeBlock {
+  u32 mode;
+  u32 count;
+  RecordEntry entries[count];
+};
+
+struct BuddyRootBlockOffsets {
+  u32 count;
+  u8 reserved[4];
+  u32 addresses[count];
+  padding[(1024 - (count * 4))];
+};
+
+struct BuddyTableOfContentEntry {
+  u8 count;
+  char name[count];
+  u32 value;
+};
+
+struct BuddyTableOfContents {
+  u32 count;
+  BuddyTableOfContentEntry toc[count];
+};
+
+struct BuddyFreeList {
+  u32 count;
+  u32 offsets[count];
+};
+
+struct BuddyRootBlock {
+  BuddyRootBlockOffsets offsets;
+  BuddyTableOfContents toc;
+  BuddyFreeList freelists[32];
+};
+
+struct BuddyBlock {
+  u32 blockCount;
+  u8 reserved[4];
+  // padding for next multiple of 256 entries (1024 bytes)
+  u32 addresses[blockCount];
+  
+  // u8 padding[paddingCount];
+  u32 directoryCount;
+  
+  // directory entries
+  u8 count;
+  u8 name[count];
+  u32 blockNumber;
+  
+  // free lists
+  // 32 free lists
+  BuddyRootBlockOffsets off[32];
+};
+
+struct BlocksList {
+  u32 blockId [[color("E57373")]];
+  u32 internalBlocks [[color("80CBC4")]];
+  u32 countRecords [[color("ffeb3b")]];
+  u32 countBlocks [[color("64b5f6")]];
+  u32 reserved [[color("a1887f")]];
+};
+
+struct BuddyAllocator {
+  char header[4];
+  u32 offsetBookkeeping;
+  u32 sizeBookkeeping;
+  u32 offsetBookkeeping2;
+  u32 offsetData;
+  u8 reserved[12];
+  
+  BuddyRootBlock root @ offsetBookkeeping + 4;
+
+  std::print("TOC {} address 0x{:08x}",
+    root.toc.toc[0].value,
+    root.offsets.addresses[root.toc.toc[0].value] >> 0x5 << 0x5);
+
+  BlocksList blocks @ (root.offsets.addresses[root.toc.toc[0].value] >> 0x5 << 0x5) + 4;
+  
+  std::print("Blocks start at address 0x{:08x}, size 0x{:04x}",
+    root.offsets.addresses[blocks.blockId] >> 0x5 << 0x5,
+    1 << (root.offsets.addresses[blocks.blockId] & 0x1f));
+
+  TreeBlock entries @ (root.offsets.addresses[blocks.blockId] >> 0x5 << 0x5) + 4;
+};
+
+BuddyAllocator buddy @0x04;