[cpp] Copy elements of the correct size in generated array accessors for cpp codec. Issue aeron-io#402.

Author: mjpt777

sbe-tool/src/main/java/uk/co/real_logic/sbe/generation/cpp/CppGenerator.java

@@ -1108,23 +1108,25 @@ private CharSequence generateArrayProperty(
  indent + " throw std::runtime_error(\"length too large for get%1$s [E106]\");\n" +
  indent + " }\n\n" +
  "%3$s" +
- indent + " std::memcpy(dst, m_buffer + m_offset + %4$d, length);\n" +
+ indent + " std::memcpy(dst, m_buffer + m_offset + %4$d, sizeof(%5$s) * length);\n" +
  indent + " return length;\n" +
  indent + " }\n\n",
  toUpperFirstChar(propertyName),
  token.arrayLength(),
  generateArrayFieldNotPresentCondition(token.version(), indent),
- offset));
+ offset,
+ cppTypeName));
 
  sb.append(String.format(
  indent + " %1$s &put%2$s(const char *src)\n" +
  indent + " {\n" +
- indent + " std::memcpy(m_buffer + m_offset + %3$d, src, %4$d);\n" +
+ indent + " std::memcpy(m_buffer + m_offset + %3$d, src, sizeof(%4$s) * %5$d);\n" +
  indent + " return *this;\n" +
  indent + " }\n\n",
  containingClassName,
  toUpperFirstChar(propertyName),
  offset,
+ cppTypeName,
  token.arrayLength()));
 
  if (token.encoding().primitiveType() == PrimitiveType.CHAR)