Caleb Gardner
71 lines
2.1 KiB
Zig
71 lines
2.1 KiB
Zig
const std = @import("std");
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const InodeType = @import("inode.zig").Type;
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const Compression = @import("superblock.zig").Compression;
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const Header = extern struct { //use extern instead of packed, due to bit alignment
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count: u32,
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block: u32,
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num: u32,
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};
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const RawEntry = struct {
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offset: u16,
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num_offset: i16,
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type: InodeType,
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size: u16,
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name: []const u8,
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pub fn init(alloc: std.mem.Allocator, rdr: anytype) !RawEntry {
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var fixed: [8]u8 = undefined;
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_ = try rdr.read(&fixed);
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const size = std.mem.readInt(u16, fixed[6..8], .little);
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const name = try alloc.alloc(u8, size + 1);
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_ = try rdr.read(name);
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return .{
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.offset = std.mem.readInt(u16, fixed[0..2], .little),
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.num_offset = std.mem.readInt(i16, fixed[2..4], .little),
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.type = @enumFromInt(std.mem.readInt(u16, fixed[4..6], .little)),
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.size = size,
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.name = name,
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};
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}
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};
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pub const Entry = struct {
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block: u32,
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offset: u16,
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num: u32,
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type: InodeType,
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name: []const u8,
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pub fn deinit(self: Entry, alloc: std.mem.Allocator) void {
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alloc.free(self.name);
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}
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};
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pub fn readDirectory(alloc: std.mem.Allocator, rdr: anytype, size: u32) ![]Entry {
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var entries: std.ArrayList(Entry) = .init(alloc);
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errdefer entries.deinit();
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var cur_red: u32 = 3; // dir size includes "." & "..", so its actual size is off by 3.
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var hdr: Header = undefined;
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while (cur_red < size) {
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_ = try rdr.read(std.mem.asBytes(&hdr));
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cur_red += 12;
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try entries.ensureUnusedCapacity(hdr.count + 1);
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for (0..hdr.count + 1) |_| {
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const raw_ent: RawEntry = try .init(alloc, rdr);
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cur_red += 9 + raw_ent.size;
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errdefer alloc.free(raw_ent.name);
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entries.appendAssumeCapacity(.{
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.block = hdr.block,
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.offset = raw_ent.offset,
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.num = @truncate(@abs(@as(i64, hdr.num) + raw_ent.num_offset)),
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.type = raw_ent.type,
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.name = raw_ent.name,
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});
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}
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}
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return entries.toOwnedSlice();
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}
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