split_buffer.h

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#pragma once
 
#include <cstdint>
#include <cstdlib>
 
namespace esphome::split_buffer {
class SplitBuffer {
 public:
  SplitBuffer() = default;
  ~SplitBuffer();
 
  // Initialize the buffer with the desired total length; no sub-buffer will be larger than `max_buffer_size`
  bool init(size_t total_length, size_t max_buffer_size = SIZE_MAX);
 
  // Free all allocated buffers
  void free();
 
  // Access operators
  uint8_t &operator[](size_t index);
  const uint8_t &operator[](size_t index) const;
  void fill(uint8_t value) const;
 
  // Pointer to the byte at `index`; `length` is set to how many bytes are contiguous from there.
  // Returns nullptr with `length` 0 if `index` is out of range.
  const uint8_t *get_span(size_t index, size_t &length) const;
  uint8_t *get_span(size_t index, size_t &length);
  // Copy `length` bytes from `data` into the buffer starting at `index`; bytes past the end are dropped.
  void write(size_t index, const uint8_t *data, size_t length);
 
  // Get the total length
  size_t size() const { return this->total_length_; }
 
  // Get buffer information
  size_t get_buffer_count() const { return this->buffer_count_; }
 
  // Check if successfully initialized
  bool is_valid() const { return this->buffers_ != nullptr && this->buffer_count_ > 0; }
 
 private:
  uint8_t **buffers_{nullptr};
  size_t buffer_count_{0};
  size_t buffer_size_{0};
  size_t total_length_{0};
};
 
}  // namespace esphome::split_buffer