Starting work on inode decoding

inode_types/dir.zig

@@ -0,0 +1,65 @@
+const std = @import("std");
+const io = std.io;
+
+pub const DirInode = packed struct {
+    dir_block_start: u32,
+    hard_links: u32,
+    dir_table_size: u16,
+    dir_block_offset: u16,
+    parent_inode_num: u32,
+};
+
+pub fn readDirInode(rdr: io.AnyReader) !DirInode {
+    return try rdr.readStruct(DirInode);
+}
+
+pub const DirIndex = struct {
+    dir_header_offset: u32,
+    dir_table_offset: u32,
+    name_size: u32,
+    name: []const u8,
+};
+
+fn readDirIndex(rdr: io.AnyReader) !DirIndex {
+    const out = DirIndex{
+        .dir_header_offset = try rdr.readInt(u32, std.builtin.Endian.little),
+        .dir_table_offset = try rdr.readInt(u32, std.builtin.Endian.little),
+        .name_size = try rdr.readInt(u32, std.builtin.Endian.little),
+        .name = undefined,
+    };
+    const buf = try std.heap.page_allocator.alloc(u8, out.name_size);
+    defer std.heap.page_allocator.free(buf);
+    try rdr.read(buf);
+    out.name = buf[0..];
+    return out;
+}
+
+pub const ExtDirInode = struct {
+    hard_links: u32,
+    dir_table_size: u32,
+    dir_block_start: u32,
+    parent_inode_num: u32,
+    dir_index_count: u16,
+    dir_block_offset: u16,
+    xattr_index: u32,
+    indexes: []const DirIndex,
+};
+
+pub fn readExtDirInode(rdr: io.AnyReader) !ExtDirInode {
+    const out = ExtDirInode{
+        .hard_links = rdr.readInt(u32, std.builtin.Endian.little),
+        .dir_table_size = rdr.readInt(u32, std.builtin.Endian.little),
+        .dir_block_start = rdr.readInt(u32, std.builtin.Endian.little),
+        .parent_inode_num = rdr.readInt(u32, std.builtin.Endian.little),
+        .dir_index_count = rdr.readInt(u16, std.builtin.Endian.little),
+        .dir_block_offset = rdr.readInt(u16, std.builtin.Endian.little),
+        .xattr_index = rdr.readInt(u32, std.builtin.Endian.little),
+        .indexes = undefined,
+    };
+    out.indexes = []const DirIndex{undefined} ** out.dir_index_count;
+    const i: u16 = 0;
+    while (i < out.dir_index_count) : (i += 1) {
+        out.indexes[i] = try readDirIndex(rdr);
+    }
+    return out;
+}