1 files changed, 90 insertions, 0 deletions
diff --git a/lib/std/compress/lzma.zig b/lib/std/compress/lzma.zig
new file mode 100644
index 0000000000..8bb8c19da1
--- /dev/null
+++ b/lib/std/compress/lzma.zig
@@ -0,0 +1,90 @@
+const std = @import("../std.zig");
+const math = std.math;
+const mem = std.mem;
+const Allocator = std.mem.Allocator;
+
+pub const decode = @import("lzma/decode.zig");
+
+pub fn decompress(
+    allocator: Allocator,
+    reader: anytype,
+) !Decompress(@TypeOf(reader)) {
+    return decompressWithOptions(allocator, reader, .{});
+}
+
+pub fn decompressWithOptions(
+    allocator: Allocator,
+    reader: anytype,
+    options: decode.Options,
+) !Decompress(@TypeOf(reader)) {
+    const params = try decode.Params.readHeader(reader, options);
+    return Decompress(@TypeOf(reader)).init(allocator, reader, params, options.memlimit);
+}
+
+pub fn Decompress(comptime ReaderType: type) type {
+    return struct {
+        const Self = @This();
+
+        pub const Error =
+            ReaderType.Error ||
+            Allocator.Error ||
+            error{ CorruptInput, EndOfStream, Overflow };
+
+        pub const Reader = std.io.Reader(*Self, Error, read);
+
+        allocator: Allocator,
+        in_reader: ReaderType,
+        to_read: std.ArrayListUnmanaged(u8),
+
+        buffer: decode.lzbuffer.LzCircularBuffer,
+        decoder: decode.rangecoder.RangeDecoder,
+        state: decode.DecoderState,
+
+        pub fn init(allocator: Allocator, source: ReaderType, params: decode.Params, memlimit: ?usize) !Self {
+            return Self{
+                .allocator = allocator,
+                .in_reader = source,
+                .to_read = .{},
+
+                .buffer = decode.lzbuffer.LzCircularBuffer.init(params.dict_size, memlimit orelse math.maxInt(usize)),
+                .decoder = try decode.rangecoder.RangeDecoder.init(source),
+                .state = try decode.DecoderState.init(allocator, params.properties, params.unpacked_size),
+            };
+        }
+
+        pub fn reader(self: *Self) Reader {
+            return .{ .context = self };
+        }
+
+        pub fn deinit(self: *Self) void {
+            self.to_read.deinit(self.allocator);
+            self.buffer.deinit(self.allocator);
+            self.state.deinit(self.allocator);
+            self.* = undefined;
+        }
+
+        pub fn read(self: *Self, output: []u8) Error!usize {
+            const writer = self.to_read.writer(self.allocator);
+            while (self.to_read.items.len < output.len) {
+                switch (try self.state.process(self.allocator, self.in_reader, writer, &self.buffer, &self.decoder)) {
+                    .continue_ => {},
+                    .finished => {
+                        try self.buffer.finish(writer);
+                        break;
+                    },
+                }
+            }
+            const input = self.to_read.items;
+            const n = math.min(input.len, output.len);
+            mem.copy(u8, output[0..n], input[0..n]);
+            mem.copy(u8, input, input[n..]);
+            self.to_read.shrinkRetainingCapacity(input.len - n);
+            return n;
+        }
+    };
+}
+
+test {
+    _ = @import("lzma/test.zig");
+    _ = @import("lzma/vec2d.zig");
+}