intermediate changes

ref:cde9a383711a11544ce7e107a78147fb96cc4029

1 files changed, 22 insertions, 0 deletions

diff --git a/util/stream/walk.cpp b/util/stream/walk.cpp
new file mode 100644
index 00000000000..57dc9ab036c
--- /dev/null
+++ b/util/stream/walk.cpp
@@ -0,0 +1,22 @@
+#include "walk.h"
+
+#include <util/generic/string.h>
+
+void IWalkInput::DoUndo(size_t len) {
+    Len_ += len;
+    Buf_ = static_cast<const char*>(Buf_) - len;
+}
+
+size_t IWalkInput::DoNext(const void** ptr, size_t len) {
+    if (!Len_) {
+        Len_ = DoUnboundedNext(&Buf_);
+    }
+
+    len = Min(Len_, len);
+    *ptr = Buf_;
+
+    Buf_ = static_cast<const char*>(Buf_) + len;
+    Len_ -= len;
+
+    return len;
+}