Caleb Gardner
72 lines
2.0 KiB
Zig
72 lines
2.0 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 c = @import("c");
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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(?*c.ZSTD_DCtx);
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const Self = @This();
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interface: Decompressor = .{ .decomp_fn = decomp },
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io: Io,
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ctx: []?*c.ZSTD_DCtx,
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ctx_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(?*c.ZSTD_DCtx, 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, c.ZSTD_createDCtx());
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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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.ctx = buf,
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.ctx_queue = queue,
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};
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}
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pub fn deinit(self: *Self, alloc: std.mem.Allocator) void {
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self.ctx_queue.close(self.io);
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for (self.ctx) |ctx|
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c.ZSTD_freeDCtx(ctx);
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alloc.free(self.ctx);
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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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return statelessDecomp(d, alloc, in, out);
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}
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var self: *Self = @fieldParentPtr("interface", @constCast(d.?));
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const ctx = self.ctx_queue.getOne(self.io) catch return Error.ReadFailed;
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defer self.ctx_queue.putOne(self.io, ctx) catch {};
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_ = c.ZSTD_DCtx_reset(ctx, c.ZSTD_reset_session_only);
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const res = c.ZSTD_decompressDCtx(ctx, out.ptr, out.len, in.ptr, in.len);
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if (c.ZSTD_isError(res) != 0)
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return Error.ReadFailed;
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return res;
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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, _: std.mem.Allocator, in: []u8, out: []u8) Error!usize {
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const res = c.ZSTD_decompress(out.ptr, out.len, in.ptr, in.len);
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if (c.ZSTD_isError(res) != 0)
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return Error.ReadFailed;
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return res;
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}
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