WORKING: implement Buffer.

1 files changed, 124 insertions, 0 deletions

diff --git a/src/common/Buffer.cpp b/src/common/Buffer.cpp
index e69de29b..62904b17 100644
--- a/src/common/Buffer.cpp
+++ b/src/common/Buffer.cpp
@@ -0,0 +1,124 @@
+#include "cru/common/Buffer.h"
+#include <cstring>
+#include "cru/common/Exception.h"
+
+namespace cru {
+namespace {
+void CheckSize(Index size) {
+  if (size < 0) {
+    throw Exception(u"Size of buffer can't be smaller than 0.");
+  }
+}
+}  // namespace
+
+Buffer::Buffer(Index size) {
+  CheckSize(size);
+  if (size == 0) {
+    ptr_ = nullptr;
+    size_ = used_size_ = 0;
+  } else {
+    ptr_ = new std::byte[size];
+    size_ = size;
+    used_size_ = 0;
+  }
+}
+
+Buffer::Buffer(const Buffer& other) { Copy_(other); }
+
+Buffer::Buffer(Buffer&& other) noexcept { Move_(std::move(other)); }
+
+Buffer& Buffer::operator=(const Buffer& other) {
+  if (this != &other) {
+    Delete_();
+    Copy_(other);
+  }
+  return *this;
+}
+
+Buffer& Buffer::operator=(Buffer&& other) noexcept {
+  if (this != &other) {
+    Delete_();
+    Move_(std::move(other));
+  }
+  return *this;
+}
+
+Buffer::~Buffer() { Delete_(); }
+
+void Buffer::AssignBytes(Index dst_offset, std::byte* src, Index src_offset,
+                         Index src_size) {
+  std::memcpy(ptr_ + dst_offset, src + src_offset, src_size);
+}
+
+void Buffer::SetUsedSize(Index new_size) { used_size_ = new_size; }
+
+void Buffer::ResizeBuffer(Index new_size, bool preserve_used) {
+  if (new_size == 0) {
+    Delete_();
+    ptr_ = nullptr;
+    size_ = used_size_ = 0;
+    return;
+  }
+
+  auto old_ptr = ptr_;
+
+  ptr_ = new std::byte[new_size];
+  size_ = new_size;
+
+  if (old_ptr) {
+    if (preserve_used) {
+      auto copy_size = std::min(used_size_, new_size);
+      std::memcpy(ptr_, old_ptr, copy_size);
+      used_size_ = copy_size;
+    }
+    delete[] old_ptr;
+  }
+}
+
+Index Buffer::PushEnd(std::byte* other, Index other_size) {
+  auto copy_size = std::min(GetRestSize(), other_size);
+
+  if (copy_size) {
+    std::memcpy(GetUsedEndPtr(), other, copy_size);
+    used_size_ += copy_size;
+  }
+
+  return copy_size;
+}
+
+Index Buffer::PopEnd(Index size) {
+  if (used_size_ < size) {
+    used_size_ = 0;
+    return used_size_;
+  } else {
+    used_size_ -= size;
+    return size;
+  }
+}
+
+void Buffer::Copy_(const Buffer& other) {
+  if (other.ptr_ == nullptr) {
+    ptr_ = nullptr;
+    size_ = used_size_ = 0;
+  } else {
+    ptr_ = new std::byte[other.size_];
+    size_ = other.size_;
+    used_size_ = other.used_size_;
+    std::memcpy(ptr_, other.ptr_, used_size_);
+  }
+}
+
+void Buffer::Move_(Buffer&& other) noexcept {
+  ptr_ = other.ptr_;
+  size_ = other.size_;
+  used_size_ = other.used_size_;
+  other.ptr_ = nullptr;
+  other.size_ = other.used_size_ = 0;
+}
+
+void Buffer::Delete_() noexcept {
+  if (ptr_) {
+    delete[] ptr_;
+  }
+}
+}  // namespace cru