Adding upstream version 1.2.0.

Signed-off-by: Daniel Baumann <daniel@debian.org>

list_at.go

@@ -0,0 +1,47 @@
+package buffer
+
+import "math"
+
+// ListAt is a slice of BufferAt's, it's the backing for NewPartitionAt
+type ListAt []BufferAt
+
+// Len is the sum of the Len()'s of the BufferAt's in the list.
+func (l *ListAt) Len() (n int64) {
+	for _, buffer := range *l {
+		if n > math.MaxInt64-buffer.Len() {
+			return math.MaxInt64
+		}
+		n += buffer.Len()
+	}
+	return n
+}
+
+// Cap is the sum of the Cap()'s of the BufferAt's in the list.
+func (l *ListAt) Cap() (n int64) {
+	for _, buffer := range *l {
+		if n > math.MaxInt64-buffer.Cap() {
+			return math.MaxInt64
+		}
+		n += buffer.Cap()
+	}
+	return n
+}
+
+// Reset calls Reset() on each of the BufferAt's in the list.
+func (l *ListAt) Reset() {
+	for _, buffer := range *l {
+		buffer.Reset()
+	}
+}
+
+// Push adds a BufferAt to the end of the list
+func (l *ListAt) Push(b BufferAt) {
+	*l = append(*l, b)
+}
+
+// Pop removes and returns a BufferAt from the front of the list
+func (l *ListAt) Pop() (b BufferAt) {
+	b = (*l)[0]
+	*l = (*l)[1:]
+	return b
+}