49 lines
1.3 KiB
Zig
49 lines
1.3 KiB
Zig
const std = @import("std");
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const sys = @import("./sys.zig");
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///
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/// An entry block of an Oar archive file.
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///
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/// Typically, following this block in memory is the file data it holds the meta-information for.
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///
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pub const Entry = extern struct {
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signature: [3]u8,
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revision: u8,
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name_length: u8,
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name_buffer: [255]u8 = std.mem.zeroes([255]u8),
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file_size: u64,
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padding: [244]u8,
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///
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/// Returns `true` if `entry` correctly identifies itself as a valid Oar entry, otherwise
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/// `false`.
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///
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pub fn isValid(entry: Entry) bool {
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return std.mem.eql(u8, &entry.signature, "oar");
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}
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///
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/// Attempts to read an [Entry] from `file_access` at its current cursor position.
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///
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/// Returns the read [Entry] value or `null` if the end of file is reached before completing the
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/// read.
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///
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pub fn read(file_access: *sys.FileAccess) sys.FileAccess.Error!?Entry {
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var entry = std.mem.zeroes(Entry);
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const origin = try file_access.queryCursor();
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if ((try file_access.read(std.mem.asBytes(&entry))) != @sizeOf(Entry)) {
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try file_access.seek(origin);
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return null;
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}
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return entry;
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}
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///
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/// Magic identifier used to validate [Entry] data.
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///
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const signature_magic = "oar";
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};
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