Caleb Gardner
75 lines
2.1 KiB
Zig
75 lines
2.1 KiB
Zig
const std = @import("std");
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const Io = std.Io;
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const Reader = std.Io.Reader;
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const zstd = std.compress.zstd;
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const Node = std.SinglyLinkedList.Node;
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const Decompressor = @import("../util/decompressor.zig");
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const Error = Decompressor.Error;
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const Queue = std.Io.Queue([]u8);
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const Self = @This();
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interface: Decompressor = .{ .decomp_fn = decomp },
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alloc: std.mem.Allocator,
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io: Io,
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block_size: u32,
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buf: [][]u8,
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buf_queue: Queue,
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pub fn init(alloc: std.mem.Allocator, io: Io, block_size: u32) !Self {
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const buf = try alloc.alloc([]u8, 20); // TODO: Choose a better number instead of a random one.
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var queue: Queue = .init(buf);
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for (0..20) |_|
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try queue.putOne(io, try alloc.alloc(u8, block_size + zstd.block_size_max));
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return .{
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.alloc = alloc,
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.io = io,
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.block_size = block_size,
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.buf = buf,
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.buf_queue = queue,
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};
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}
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pub fn deinit(self: *Self) void {
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self.buf_queue.close(self.io);
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for (self.buf) |buf|
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self.alloc.free(buf);
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self.alloc.free(self.buf);
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}
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fn decomp(d: ?*const Decompressor, alloc: std.mem.Allocator, in: []u8, out: []u8) Error!usize {
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if (d == null) {
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const buf = try alloc.alloc(u8, in.len * 2);
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defer alloc.free(buf);
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return zstdDecomp(buf, in, out);
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}
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var self: *Self = @fieldParentPtr("interface", @constCast(d.?));
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const buf = self.buf_queue.getOne(self.io) catch return Error.ReadFailed;
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defer self.buf_queue.putOne(self.io, buf) catch {};
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return zstdDecomp(buf, in, out);
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}
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inline fn zstdDecomp(buffer: []u8, in: []u8, out: []u8) !usize {
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var rdr: Reader = .fixed(in);
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var d = zstd.Decompress.init(&rdr, buffer, .{ .window_len = @truncate(out.len) });
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return d.reader.readSliceShort(out);
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}
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// Stateless
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pub const stateless_decompressor: Decompressor = .{ .decomp_fn = statelessDecomp };
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fn statelessDecomp(_: ?*const Decompressor, alloc: std.mem.Allocator, in: []u8, out: []u8) Error!usize {
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const buf = try alloc.alloc(u8, out.len + zstd.block_size_max);
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defer alloc.free(buf);
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return zstdDecomp(buf, in, out);
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}
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