From 34524a179227d1492229f52b93c61405455c47e8 Mon Sep 17 00:00:00 2001
From: daurnimator <quae@daurnimator.com>
Date: Thu, 2 Apr 2020 21:14:15 +1100
Subject: [PATCH] std: add LinearFifo().inStream

---
 lib/std/fifo.zig | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/lib/std/fifo.zig b/lib/std/fifo.zig
index c97b0542b0..6bbec57072 100644
--- a/lib/std/fifo.zig
+++ b/lib/std/fifo.zig
@@ -215,6 +215,16 @@ pub fn LinearFifo(
             return dst.len - dst_left.len;
         }
 
+        /// Same as `read` except it returns an error union
+        /// The purpose of this function existing is to match `std.io.InStream` API.
+        fn readFn(self: *Self, dest: []u8) error{}!usize {
+            return self.read(dest);
+        }
+
+        pub fn inStream(self: *Self) std.io.InStream(*Self, error{}, readFn) {
+            return .{ .context = self };
+        }
+
         /// Returns number of items available in fifo
         pub fn writableLength(self: Self) usize {
             return self.buf.len - self.count;
@@ -414,6 +424,15 @@ test "LinearFifo(u8, .Dynamic)" {
         testing.expectEqualSlices(u8, "Hello, World!", result[0..fifo.read(&result)]);
         testing.expectEqual(@as(usize, 0), fifo.readableLength());
     }
+
+    {
+        try fifo.outStream().writeAll("This is a test");
+        var result: [30]u8 = undefined;
+        testing.expectEqualSlices(u8, "This", (try fifo.inStream().readUntilDelimiterOrEof(&result, ' ')).?);
+        testing.expectEqualSlices(u8, "is", (try fifo.inStream().readUntilDelimiterOrEof(&result, ' ')).?);
+        testing.expectEqualSlices(u8, "a", (try fifo.inStream().readUntilDelimiterOrEof(&result, ' ')).?);
+        testing.expectEqualSlices(u8, "test", (try fifo.inStream().readUntilDelimiterOrEof(&result, ' ')).?);
+    }
 }
 
 test "LinearFifo" {