intermediate changes

ref:cde9a383711a11544ce7e107a78147fb96cc4029

1 files changed, 104 insertions, 0 deletions

diff --git a/library/cpp/json/rapidjson_helpers.h b/library/cpp/json/rapidjson_helpers.h
new file mode 100644
index 0000000000..aeb96ff670
--- /dev/null
+++ b/library/cpp/json/rapidjson_helpers.h
@@ -0,0 +1,104 @@
+#pragma once
+
+#include <util/generic/strbuf.h>
+#include <util/stream/input.h>
+
+namespace NJson {
+    struct TReadOnlyStreamBase {
+        using Ch = char;
+
+        Ch* PutBegin() {
+            Y_ASSERT(false);
+            return nullptr;
+        }
+
+        void Put(Ch) {
+            Y_ASSERT(false);
+        }
+
+        void Flush() {
+            Y_ASSERT(false);
+        }
+
+        size_t PutEnd(Ch*) {
+            Y_ASSERT(false);
+            return 0;
+        }
+    };
+
+    struct TInputStreamWrapper : TReadOnlyStreamBase {
+        Ch Peek() const {
+            if (!Eof) {
+                if (Pos >= Sz) {
+                    if (Sz < BUF_SIZE) {
+                        Sz += Helper.Read(Buf + Sz, BUF_SIZE - Sz);
+                    } else {
+                        Sz = Helper.Read(Buf, BUF_SIZE);
+                        Pos = 0;
+                    }
+                }
+
+                if (Pos < Sz) {
+                    return Buf[Pos];
+                }
+            }
+
+            Eof = true;
+            return 0;
+        }
+
+        Ch Take() {
+            auto c = Peek();
+            ++Pos;
+            ++Count;
+            return c;
+        }
+
+        size_t Tell() const {
+            return Count;
+        }
+
+        TInputStreamWrapper(IInputStream& helper)
+            : Helper(helper)
+            , Eof(false)
+            , Sz(0)
+            , Pos(0)
+            , Count(0)
+        {
+        }
+
+        static const size_t BUF_SIZE = 1 << 12;
+
+        IInputStream& Helper;
+        mutable char Buf[BUF_SIZE];
+        mutable bool Eof;
+        mutable size_t Sz;
+        mutable size_t Pos;
+        size_t Count;
+    };
+
+    struct TStringBufStreamWrapper : TReadOnlyStreamBase {
+        Ch Peek() const {
+            return Pos < Data.size() ? Data[Pos] : 0;
+        }
+
+        Ch Take() {
+            auto c = Peek();
+            ++Pos;
+            return c;
+        }
+
+        size_t Tell() const {
+            return Pos;
+        }
+
+        TStringBufStreamWrapper(TStringBuf data)
+            : Data(data)
+            , Pos(0)
+        {
+        }
+
+        TStringBuf Data;
+        size_t Pos;
+    };
+}