Merge branch 'master' into crc

1 files changed, 30 insertions, 0 deletions

diff --git a/lib/std/compress.zig b/lib/std/compress.zig
index 7fa25175d5..3c52002cfc 100644
--- a/lib/std/compress.zig
+++ b/lib/std/compress.zig
@@ -4,6 +4,36 @@ pub const deflate = @import("compress/deflate.zig");
 pub const gzip = @import("compress/gzip.zig");
 pub const zlib = @import("compress/zlib.zig");
 
+pub fn HashedReader(
+    comptime ReaderType: anytype,
+    comptime HasherType: anytype,
+) type {
+    return struct {
+        child_reader: ReaderType,
+        hasher: HasherType,
+
+        pub const Error = ReaderType.Error;
+        pub const Reader = std.io.Reader(*@This(), Error, read);
+
+        pub fn read(self: *@This(), buf: []u8) Error!usize {
+            const amt = try self.child_reader.read(buf);
+            self.hasher.update(buf);
+            return amt;
+        }
+
+        pub fn reader(self: *@This()) Reader {
+            return .{ .context = self };
+        }
+    };
+}
+
+pub fn hashedReader(
+    reader: anytype,
+    hasher: anytype,
+) HashedReader(@TypeOf(reader), @TypeOf(hasher)) {
+    return .{ .child_reader = reader, .hasher = hasher };
+}
+
 test {
     _ = deflate;
     _ = gzip;