Caleb J. Gardner
61 lines
1.9 KiB
Zig
61 lines
1.9 KiB
Zig
//! Directory entry from the directory table.
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const std = @import("std");
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const Reader = std.Io.Reader;
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const InodeType = @import("inode.zig").InodeType;
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const Entry = @This();
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const Header = extern struct { // use extern due to bad alignment with packed.
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count: u32,
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block_start: u32,
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num: u32,
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};
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const RawEntry = packed struct {
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offset: u16,
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inode_offset: i16,
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inode_type: InodeType,
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name_size: u16,
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};
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block_start: u32,
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block_offset: u16,
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num: u32,
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inode_type: InodeType,
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name: []const u8,
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pub fn readDir(alloc: std.mem.Allocator, rdr: *Reader, size: u32) ![]Entry {
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var cur_red: u32 = 3; // start at 3 due to "." & ".." being counted in the dir size.
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var hdr: Header = undefined;
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var raw: RawEntry = undefined;
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var out: std.ArrayList(Entry) = try .initCapacity(alloc, 100); // Start out with a decent capacity instead of needing to allocate per header.
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errdefer out.deinit(alloc);
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while (cur_red < size) {
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try rdr.readSliceEndian(Header, @ptrCast(&hdr), .little);
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cur_red += @sizeOf(Header);
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try out.ensureUnusedCapacity(alloc, hdr.count + 1);
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for (0..hdr.count + 1) |_| {
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try rdr.readSliceEndian(RawEntry, @ptrCast(&raw), .little);
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const name = try alloc.alloc(u8, raw.name_size + 1);
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errdefer alloc.free(name);
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try rdr.readSliceEndian(u8, name, .little);
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const val = out.addOneAssumeCapacity();
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val.* = .{
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.block_start = hdr.block_start,
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.block_offset = raw.offset,
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.num = @abs(hdr.num + raw.offset),
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.inode_type = raw.inode_type,
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.name = name,
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};
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cur_red += @sizeOf(RawEntry) + raw.name_size + 1;
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}
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}
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return out.toOwnedSlice(alloc);
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}
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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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