intermediate changes

ref:cde9a383711a11544ce7e107a78147fb96cc4029

1 files changed, 18 insertions, 0 deletions

diff --git a/util/stream/zerocopy_output.cpp b/util/stream/zerocopy_output.cpp
new file mode 100644
index 0000000000..23600ef6e1
--- /dev/null
+++ b/util/stream/zerocopy_output.cpp
@@ -0,0 +1,18 @@
+#include "zerocopy_output.h"
+
+#include <util/generic/utility.h>
+
+void IZeroCopyOutput::DoWrite(const void* buf, size_t len) {
+    void* ptr = nullptr;
+    size_t writtenBytes = 0;
+    while (writtenBytes < len) {
+        size_t bufferSize = DoNext(&ptr);
+        Y_ASSERT(ptr && bufferSize > 0);
+        size_t toWrite = Min(bufferSize, len - writtenBytes);
+        memcpy(ptr, static_cast<const char*>(buf) + writtenBytes, toWrite);
+        writtenBytes += toWrite;
+        if (toWrite < bufferSize) {
+            DoUndo(bufferSize - toWrite);
+        }
+    }
+}