add a separate Buffer class

3 files changed, 76 insertions, 8 deletions

diff --git a/include/winapi/buffer.hpp b/include/winapi/buffer.hpp
new file mode 100644
index 0000000..246822e
--- /dev/null
+++ b/include/winapi/buffer.hpp
@@ -0,0 +1,69 @@
+// Copyright (c) 2020 Egor Tensin <Egor.Tensin@gmail.com>
+// This file is part of the "winapi-common" project.
+// For details, see https://github.com/egor-tensin/winapi-common.
+// Distributed under the MIT License.
+
+#pragma once
+
+#include <cstddef>
+#include <cstring>
+#include <sstream>
+#include <stdexcept>
+#include <string>
+#include <utility>
+#include <vector>
+
+namespace winapi {
+
+class Buffer : public std::vector<unsigned char> {
+public:
+    typedef std::vector<unsigned char> Parent;
+
+    Buffer() = default;
+
+    explicit Buffer(Parent&& src) : Parent(std::move(src)) {}
+
+    template <typename CharT>
+    explicit Buffer(const std::basic_string<CharT>& src) {
+        set(src);
+    }
+
+    explicit Buffer(const void* src, std::size_t nb) { set(src, nb); }
+
+    template <typename CharT>
+    void set(const std::basic_string<CharT>& src) {
+        set(src.c_str(), src.length() * sizeof(std::basic_string<CharT>::char_type));
+    }
+
+    void set(const void* src, std::size_t nb) {
+        resize(nb);
+        std::memcpy(data(), src, nb);
+    }
+
+    std::string as_utf8() const {
+        const auto c_str = reinterpret_cast<const char*>(data());
+        const auto nb = size();
+        const auto nch = nb;
+        return {c_str, nch};
+    }
+
+    std::wstring as_utf16() const {
+        const auto c_str = reinterpret_cast<const wchar_t*>(data());
+        const auto nb = size();
+        if (nb % 2 != 0) {
+            std::ostringstream oss;
+            oss << "Buffer size invalid at " << nb << " bytes";
+            throw std::runtime_error{oss.str()};
+        }
+        const auto nch = nb / 2;
+        return {c_str, nch};
+    }
+
+    void add(const Buffer& src) {
+        const auto nb = size();
+        resize(size() + src.size());
+        std::memcpy(data() + nb, src.data(), src.size());
+    }
+};
+
+} // namespace winapi
diff --git a/include/winapi/handle.hpp b/include/winapi/handle.hpp
index af37424..5f813bc 100644
--- a/include/winapi/handle.hpp
+++ b/include/winapi/handle.hpp
@@ -5,6 +5,8 @@
 
 #pragma once
 
+#include "buffer.hpp"
+
 #include <boost/config.hpp>
 
 #include <windows.h>
@@ -12,7 +14,6 @@
 #include <cstddef>
 #include <memory>
 #include <utility>
-#include <vector>
 
 namespace winapi {
 
@@ -37,8 +38,6 @@ public:
     static Handle std_out();
     static Handle std_err();
 
-    typedef std::vector<unsigned char> Buffer;
-
     Buffer read() const;
 
     BOOST_STATIC_CONSTEXPR std::size_t max_chunk_size = 16 * 1024;
diff --git a/src/handle.cpp b/src/handle.cpp
index a6ab3a5..1147cf6 100644
--- a/src/handle.cpp
+++ b/src/handle.cpp
@@ -3,6 +3,7 @@
 // For details, see https://github.com/egor-tensin/winapi-common.
 // Distributed under the MIT License.
 
+#include <winapi/buffer.hpp>
 #include <winapi/error.hpp>
 #include <winapi/handle.hpp>
 #include <winapi/workarounds.hpp>
@@ -15,6 +16,7 @@
 #include <cstddef>
 #include <sstream>
 #include <stdexcept>
+#include <utility>
 
 namespace winapi {
 namespace {
@@ -100,15 +102,13 @@ bool Handle::read_chunk(Buffer& buffer) const {
     }
 }
 
-Handle::Buffer Handle::read() const {
+Buffer Handle::read() const {
     Buffer buffer;
-    Buffer chunk;
 
     while (true) {
+        Buffer chunk;
         const auto next = read_chunk(chunk);
-
-        buffer.reserve(buffer.size() + chunk.size());
-        buffer.insert(buffer.cend(), chunk.cbegin(), chunk.cend());
+        buffer.add(chunk);
 
         if (!next) {
             break;