Introduce LocalBuffer

include/tscpp/util/LocalBuffer.h

@@ -0,0 +1,72 @@
+/** @file
+
+   LocalBuffer
+
+   @section license License
+
+   Licensed to the Apache Software Foundation (ASF) under one
+   or more contributor license agreements.  See the NOTICE file
+   distributed with this work for additional information
+   regarding copyright ownership.  The ASF licenses this file
+   to you under the Apache License, Version 2.0 (the
+   "License"); you may not use this file except in compliance
+   with the License.  You may obtain a copy of the License at
+
+   http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+ */
+
+#pragma once
+
+namespace ts
+{
+template <class T = uint8_t, std::size_t EstSizeBound = 1024> class LocalBuffer
+{
+public:
+  LocalBuffer(std::size_t size)
+    : _ptr(size == 0 ? nullptr : (size > EstSizeBound ? new T[size] : _buf)),
+      _size((0 < size && size <= EstSizeBound) ? EstSizeBound : size)
+  {
+  }
+  ~LocalBuffer();
+
+  // Don't allocate on heap
+  void *operator new(std::size_t)   = delete;
+  void *operator new[](std::size_t) = delete;
+
+  T *data() const;
+  std::size_t size() const;
+
+private:
+  T _buf[EstSizeBound];
+  T *const _ptr;
+  const std::size_t _size;
+};
+
+template <class T, std::size_t S> LocalBuffer<T, S>::~LocalBuffer()
+{
+  if (_ptr && _ptr != _buf) {
+    delete[] _ptr;
+  }
+}
+
+template <class T, std::size_t S>
+inline T *
+LocalBuffer<T, S>::data() const
+{
+  return _ptr;
+}
+
+template <class T, std::size_t S>
+inline std::size_t
+LocalBuffer<T, S>::size() const
+{
+  return _size;
+}
+
+} // namespace ts

include/tscpp/util/Makefile.am

@@ -20,5 +20,6 @@ library_includedir=$(includedir)/tscpp/util
 
 library_include_HEADERS = \
 	IntrusiveDList.h \
-        PostScript.h \
-        TextView.h
+	LocalBuffer.h \
+	PostScript.h \
+	TextView.h

src/tscpp/util/Makefile.am

@@ -38,6 +38,7 @@ test_tscpputil_CXXFLAGS = -Wno-array-bounds $(AM_CXXFLAGS)
 test_tscpputil_LDADD = libtscpputil.la
 test_tscpputil_SOURCES = \
 	unit_tests/unit_test_main.cc \
+	unit_tests/test_LocalBuffer.cc \
 	unit_tests/test_MemSpan.cc \
 	unit_tests/test_PostScript.cc \
 	unit_tests/test_TextView.cc \

src/tscpp/util/unit_tests/test_LocalBuffer.cc

@@ -0,0 +1,111 @@
+/** @file
+
+    Unit tests for LocalBuffer
+
+    @section license License
+
+    Licensed to the Apache Software Foundation (ASF) under one
+    or more contributor license agreements.  See the NOTICE file
+    distributed with this work for additional information
+    regarding copyright ownership.  The ASF licenses this file
+    to you under the Apache License, Version 2.0 (the
+    "License"); you may not use this file except in compliance
+    with the License.  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+    Unless required by applicable law or agreed to in writing, software
+    distributed under the License is distributed on an "AS IS" BASIS,
+    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+    See the License for the specific language governing permissions and
+    limitations under the License.
+ */
+
+#include "catch.hpp"
+#include "tscpp/util/LocalBuffer.h"
+
+#include <cstring>
+
+TEST_CASE("LocalBuffer", "[libts][LocalBuffer]")
+{
+  SECTION("EstSizeBound = default")
+  {
+    SECTION("size = 0")
+    {
+      const size_t len = 0;
+      ts::LocalBuffer local_buffer(len);
+      uint8_t *buf = local_buffer.data();
+
+      CHECK(buf == nullptr);
+      CHECK(local_buffer.size() == 0);
+    }
+
+    SECTION("size = 1024")
+    {
+      const size_t len = 1024;
+      ts::LocalBuffer local_buffer(len);
+      uint8_t *buf = local_buffer.data();
+
+      memset(buf, 0xAA, len);
+
+      CHECK(buf[0] == 0xAA);
+      CHECK(buf[len - 1] == 0xAA);
+      CHECK(local_buffer.size() == 1024);
+    }
+
+    SECTION("size = 2048")
+    {
+      const size_t len = 2048;
+      ts::LocalBuffer local_buffer(len);
+      uint8_t *buf = local_buffer.data();
+
+      memset(buf, 0xAA, len);
+
+      CHECK(buf[0] == 0xAA);
+      CHECK(buf[len - 1] == 0xAA);
+      CHECK(local_buffer.size() == 2048);
+    }
+  }
+
+  SECTION("EstSizeBound = 2048")
+  {
+    SECTION("size = 1024")
+    {
+      const size_t len = 1024;
+      ts::LocalBuffer<uint8_t, 2048> local_buffer(len);
+      uint8_t *buf = local_buffer.data();
+
+      memset(buf, 0xAA, len);
+
+      CHECK(buf[0] == 0xAA);
+      CHECK(buf[len - 1] == 0xAA);
+      CHECK(local_buffer.size() == 2048);
+    }
+
+    SECTION("size = 2048")
+    {
+      const size_t len = 2048;
+      ts::LocalBuffer<uint8_t, 2048> local_buffer(len);
+      uint8_t *buf = local_buffer.data();
+
+      memset(buf, 0xAA, len);
+
+      CHECK(buf[0] == 0xAA);
+      CHECK(buf[len - 1] == 0xAA);
+      CHECK(local_buffer.size() == 2048);
+    }
+
+    SECTION("size = 4096")
+    {
+      const size_t len = 4096;
+      ts::LocalBuffer<uint8_t, 2048> local_buffer(len);
+      uint8_t *buf = local_buffer.data();
+
+      memset(buf, 0xAA, len);
+
+      CHECK(buf[0] == 0xAA);
+      CHECK(buf[len - 1] == 0xAA);
+      CHECK(local_buffer.size() == 4096);
+    }
+  }
+}