Fixed LimitReadBuffer [#CLICKHOUSE-2].

dbms/src/IO/LimitReadBuffer.cpp

@@ -22,7 +22,14 @@ bool LimitReadBuffer::nextImpl()
 
 
 LimitReadBuffer::LimitReadBuffer(ReadBuffer & in_, size_t limit_)
-    : ReadBuffer(nullptr, 0), in(in_), limit(limit_) {}
+    : ReadBuffer(in_.position(), 0), in(in_), limit(limit_)
+{
+    size_t remaining_bytes_in_buffer = in.buffer().end() - in.position();
+    if (remaining_bytes_in_buffer > limit)
+        remaining_bytes_in_buffer = limit;
+
+    working_buffer = Buffer(in.position(), in.position() + remaining_bytes_in_buffer);
+}
 
 
 LimitReadBuffer::~LimitReadBuffer()

dbms/src/IO/tests/limit_read_buffer.cpp

@@ -14,11 +14,20 @@ int main(int argc, char ** argv)
     size_t limit = std::stol(argv[1]);
 
     ReadBufferFromFileDescriptor in(STDIN_FILENO);
-    LimitReadBuffer limit_in(in, limit);
-
     WriteBufferFromFileDescriptor out(STDOUT_FILENO);
 
-    copyData(limit_in, out);
+    writeCString("--- first ---\n", out);
+    {
+        LimitReadBuffer limit_in(in, limit);
+        copyData(limit_in, out);
+    }
+
+    writeCString("\n--- second ---\n", out);
+    {
+        LimitReadBuffer limit_in(in, limit);
+        copyData(limit_in, out);
+    }
+
     writeCString("\n--- the rest ---\n", out);
     copyData(in, out);
 

dbms/src/IO/tests/limit_read_buffer.reference

@@ -1,3 +1,6 @@
+--- first ---
 Hello, wor
+--- second ---
+ld! Abcdef
 --- the rest ---
-ld!
+ghijklmnopqrstuvwxyz.

dbms/src/IO/tests/limit_read_buffer.sh

@@ -1,2 +1,2 @@
 #!/usr/bin/env bash
-./limit_read_buffer 10 <<< "Hello, world!"
+./limit_read_buffer 10 <<< 'Hello, world! Abcdefghijklmnopqrstuvwxyz.'