Caleb J. Gardner
77 lines
2.8 KiB
Zig
77 lines
2.8 KiB
Zig
const std = @import("std");
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const Reader = std.Io.Reader;
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pub const BlockSize = packed struct {
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size: u24,
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uncompressed: bool,
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_: u7,
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};
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pub const File = struct {
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block_start: u32, // bytes 0-3
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frag_idx: u32, // bytes 4-7
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frag_block_offset: u32, // bytes 8-11
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size: u32, // bytes 12-15
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block_sizes: []BlockSize,
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pub fn read(alloc: std.mem.Allocator, rdr: *Reader, block_size: u32) !File {
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var start: [16]u8 = undefined;
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try rdr.readSliceAll(&start);
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const frag_idx: u32 = std.mem.readInt(u32, start[4..8], .little);
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const size: u32 = std.mem.readInt(u32, start[12..16], .little);
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var num_blocks: u32 = size / block_size;
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if (size % block_size != 0 and frag_idx == 0xFFFFFFFF) num_blocks += 1;
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const sizes = try alloc.alloc(BlockSize, num_blocks);
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errdefer alloc.free(sizes);
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try rdr.readSliceEndian(BlockSize, sizes, .little);
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return .{
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.block_start = std.mem.readInt(u32, start[0..4], .little),
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.frag_idx = frag_idx,
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.frag_block_offset = std.mem.readInt(u32, start[8..12], .little),
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.size = size,
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.block_sizes = sizes,
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};
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}
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pub fn deinit(self: File, alloc: std.mem.Allocator) void {
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alloc.free(self.block_sizes);
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}
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};
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pub const ExtFile = struct {
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block_start: u64, // bytes 0-7
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size: u64, // bytes 8-15
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sparse: u64, // bytes 16-23
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hard_links: u32, // bytes 24-27
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frag_idx: u32, // bytes 28-31
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frag_block_offset: u32, // bytes 32-35
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xattr_idx: u32, // bytes 36-39
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block_sizes: []BlockSize,
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pub fn read(alloc: std.mem.Allocator, rdr: *Reader, block_size: u32) !ExtFile {
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var start: [40]u8 = undefined;
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try rdr.readSliceAll(&start);
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const frag_idx: u32 = std.mem.readInt(u32, start[28..32], .little);
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const size: u64 = std.mem.readInt(u64, start[8..16], .little);
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var num_blocks: u32 = @truncate(size / block_size);
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if (size % block_size != 0 and frag_idx == 0xFFFFFFFF) num_blocks += 1;
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const sizes = try alloc.alloc(BlockSize, num_blocks);
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errdefer alloc.free(sizes);
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try rdr.readSliceEndian(BlockSize, sizes, .little);
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return .{
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.block_start = std.mem.readInt(u64, start[0..8], .little),
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.size = size,
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.sparse = std.mem.readInt(u64, start[16..24], .little),
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.hard_links = std.mem.readInt(u32, start[24..28], .little),
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.frag_idx = frag_idx,
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.frag_block_offset = std.mem.readInt(u32, start[32..36], .little),
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.xattr_idx = std.mem.readInt(u32, start[36..40], .little),
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.block_sizes = sizes,
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};
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}
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pub fn deinit(self: ExtFile, alloc: std.mem.Allocator) void {
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alloc.free(self.block_sizes);
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}
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};
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