bufferview.h

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#pragma once
 
 
#include <promeki/config.h>
#if PROMEKI_ENABLE_CORE
#include <cstdint>
#include <initializer_list>
#include <promeki/buffer.h>
#include <promeki/list.h>
 
PROMEKI_NAMESPACE_BEGIN
 
class BufferView {
        public:
                // ---- Per-slice proxy ------------------------------
 
                class Entry {
                                friend class BufferView;
 
                        public:
                                Entry() = default;
 
                                const Buffer &buffer() const;
 
                                size_t bufferIndex() const;
 
                                size_t offset() const;
 
                                size_t size() const;
 
                                uint8_t *data();
 
                                const uint8_t *data() const;
 
                                bool isValid() const;
 
                                bool isNull() const { return !isValid(); }
 
                        private:
                                const BufferView *_list = nullptr;
                                size_t            _idx = 0;
 
                                Entry(const BufferView *list, size_t idx) : _list(list), _idx(idx) {}
                };
 
                // ---- Iteration -----------------------------------
 
                class Iterator {
                                friend class BufferView;
 
                        public:
                                Iterator() = default;
                                Entry     operator*() const { return Entry(_list, _idx); }
                                Iterator &operator++() {
                                        ++_idx;
                                        return *this;
                                }
                                Iterator operator++(int) {
                                        Iterator t(*this);
                                        ++_idx;
                                        return t;
                                }
                                bool operator==(const Iterator &o) const { return _list == o._list && _idx == o._idx; }
                                bool operator!=(const Iterator &o) const { return !(*this == o); }
 
                        private:
                                const BufferView *_list = nullptr;
                                size_t            _idx = 0;
 
                                Iterator(const BufferView *list, size_t idx) : _list(list), _idx(idx) {}
                };
 
                // ---- Construction --------------------------------
 
                BufferView() = default;
 
                BufferView(Buffer buf, size_t offset, size_t size);
 
                BufferView(std::initializer_list<BufferView> init);
 
                // ---- List operations -----------------------------
 
                size_t count() const { return _views.size(); }
 
                bool isEmpty() const { return _views.isEmpty(); }
 
                Entry operator[](size_t i) const { return Entry(this, i); }
 
                Iterator begin() const { return Iterator(this, 0); }
                Iterator end() const { return Iterator(this, _views.size()); }
 
                // ---- Single-slice convenience accessors ----------
                //
                // These treat the list as a single byte blob.  When
                // the list holds exactly one slice they forward to
                // that slice; on an empty list they return empty /
                // zero / nullptr values.  Call sites that manipulate
                // multi-slice lists should use @c operator[] or
                // iteration rather than these helpers.
 
                const Buffer &buffer() const;
 
                size_t offset() const;
 
                uint8_t *data();
 
                const uint8_t *data() const;
 
                bool isValid() const;
 
                bool isNull() const { return !isValid(); }
 
                void pushToBack(Buffer buf, size_t offset, size_t size);
 
                void append(const BufferView &other);
 
                void clear();
 
                // ---- Domain operations ---------------------------
 
                size_t size() const;
 
                size_t totalSize() const { return size(); }
 
                bool isExclusive() const;
 
                void ensureExclusive();
 
                [[nodiscard]] Error seal() const;
 
        private:
                struct View {
                                size_t bufferIdx = 0;
                                size_t offset = 0;
                                size_t size = 0;
                };
 
                Buffer::List _buffers;
                List<View>      _views;
 
                // Returns the index of @p buf in @c _buffers, inserting if not found.
                // When @p buf is null, returns the largest representable size_t
                // (conceptually "no buffer"); no null entry is stored.
                size_t internBuffer(const Buffer &buf);
};
 
PROMEKI_NAMESPACE_END
 
#endif // PROMEKI_ENABLE_CORE