1 files changed, 92 insertions, 0 deletions
diff --git a/src/str_buffer.cc b/src/str_buffer.cc
new file mode 100644
index 0000000..6771cad
--- /dev/null
+++ b/src/str_buffer.cc
@@ -0,0 +1,92 @@
+#include "common.hh"
+
+#include "str_buffer.hh"
+
+#include <utility>
+
+namespace {
+
+template<typename T>
+class StringBuffer : public RoBuffer {
+public:
+  explicit StringBuffer(T str)
+    : str_(std::move(str)), offset_(0) {}
+
+  bool empty() const override {
+    return offset_ >= str_.size();
+  }
+
+  char const* rbuf(size_t /* want */, size_t& avail) override {
+    avail = str_.size() - offset_;
+    return str_.data() + offset_;
+  }
+
+  void rcommit(size_t bytes) override {
+    assert(str_.size() - offset_ >= bytes);
+    offset_ += bytes;
+  }
+
+private:
+  T str_;
+  size_t offset_;
+};
+
+class SharedStringBuffer : public Buffer {
+public:
+  explicit SharedStringBuffer(std::shared_ptr<std::string> content)
+    : content_(std::move(content)), read_ptr_(0), write_ptr_(content_->size()) {
+  }
+
+  bool empty() const override {
+    return read_ptr_ >= content_->size();
+  }
+
+  char const* rbuf(size_t /* want */, size_t& avail) override {
+    avail = content_->size() - read_ptr_;
+    return content_->data() + read_ptr_;
+  }
+
+  void rcommit(size_t bytes) override {
+    assert(content_->size() - read_ptr_ >= bytes);
+    read_ptr_ += bytes;
+  }
+
+  bool full() const override {
+    return false;
+  }
+
+  void clear() override {
+    content_->clear();
+    read_ptr_ = write_ptr_ = 0;
+  }
+
+  char* wbuf(size_t request, size_t& avail) override {
+    avail = request;
+    content_->resize(write_ptr_ + request);
+    return content_->data() + write_ptr_;
+  }
+
+  void wcommit(size_t bytes) override {
+    assert(content_->size() - write_ptr_ >= bytes);
+    write_ptr_ += bytes;
+  }
+
+private:
+  std::shared_ptr<std::string> content_;
+  size_t read_ptr_;
+  size_t write_ptr_;
+};
+
+}  // namespace
+
+std::unique_ptr<RoBuffer> make_strbuffer(std::string content) {
+  return std::make_unique<StringBuffer<std::string>>(std::move(content));
+}
+
+std::unique_ptr<RoBuffer> make_strbuffer(std::string_view content) {
+  return std::make_unique<StringBuffer<std::string_view>>(content);
+}
+
+std::unique_ptr<Buffer> make_strbuffer(std::shared_ptr<std::string> content) {
+  return std::make_unique<SharedStringBuffer>(std::move(content));
+}