From 622e0a56a6bbcf664552c03d86cd7eeab6e1de29 Mon Sep 17 00:00:00 2001
From: Jason Volk <jason@zemos.net>
Date: Mon, 19 Feb 2018 14:01:00 -0800
Subject: [PATCH] ircd::buffer: Add operator+ to compute a new buffer at
 offset.

---
 include/ircd/buffer.h | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/include/ircd/buffer.h b/include/ircd/buffer.h
index e352911f8..b952ef5b2 100644
--- a/include/ircd/buffer.h
+++ b/include/ircd/buffer.h
@@ -61,6 +61,7 @@ namespace ircd::buffer
 	template<class it> size_t size(const buffer<it> &buffer);
 	template<class it> const it &data(const buffer<it> &buffer);
 	template<class it> size_t consume(buffer<it> &buffer, const size_t &bytes);
+	template<class it> buffer<it> operator+(const buffer<it> &buffer, const size_t &bytes);
 	template<class it> it copy(it &dest, const it &stop, const const_buffer &);
 	size_t copy(const mutable_buffer &dst, const const_buffer &src);
 	size_t reverse(const mutable_buffer &dst, const const_buffer &src);
@@ -564,6 +565,22 @@ ircd::buffer::copy(it &dest,
 	return ret;
 }
 
+template<class it>
+ircd::buffer::buffer<it>
+ircd::buffer::operator+(const buffer<it> &buffer,
+                        const size_t &bytes)
+{
+	const size_t advance
+	{
+		std::min(bytes, size(buffer))
+	};
+
+	return
+	{
+		begin(buffer) + advance, size(buffer) - advance
+	};
+}
+
 template<class it>
 size_t
 ircd::buffer::consume(buffer<it> &buffer,