ply_file_buffer.hh

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/* SPDX-FileCopyrightText: 2023 Blender Authors
 *
 * SPDX-License-Identifier: GPL-2.0-or-later */
 
#pragma once
 
#include <type_traits>
 
#include "BLI_string_ref.hh"
#include "BLI_utility_mixins.hh"
#include "BLI_vector.hh"
 
/* SEP macro from BLI path utils clashes with SEP symbol in fmt headers. */
#undef SEP
#include <fmt/format.h>
 
namespace blender::io::ply {
 
class FileBuffer : private NonMovable {
  using VectorChar = Vector<char>;
  Vector<VectorChar> blocks_;
  size_t buffer_chunk_size_;
  const char *filepath_;
  FILE *outfile_;
 
 public:
  FileBuffer(const char *filepath, size_t buffer_chunk_size = 64 * 1024);
 
  virtual ~FileBuffer() = default;
 
  /* Write contents to the buffer(s) into a file, and clear the buffers. */
  void write_to_file();
 
  void close_file();
 
  virtual void write_vertex(float x, float y, float z) = 0;
 
  virtual void write_UV(float u, float v) = 0;
 
  virtual void write_data(float v) = 0;
 
  virtual void write_vertex_normal(float nx, float ny, float nz) = 0;
 
  virtual void write_vertex_color(uchar r, uchar g, uchar b, uchar a) = 0;
 
  virtual void write_vertex_end() = 0;
 
  virtual void write_face(char count, Span<uint32_t> const &vertex_indices) = 0;
 
  virtual void write_edge(int first, int second) = 0;
 
  void write_header_element(StringRef name, int count);
 
  void write_header_scalar_property(StringRef dataType, StringRef name);
 
  void write_header_list_property(StringRef countType, StringRef dataType, StringRef name);
 
  void write_string(StringRef s);
 
  void write_newline();
 
 protected:
  /* Ensure the last block contains at least this amount of free space.
   * If not, add a new block with max of block size & the amount of space needed. */
  void ensure_space(size_t at_least)
  {
    if (blocks_.is_empty() || (blocks_.last().capacity() - blocks_.last().size() < at_least)) {
      blocks_.append(VectorChar());
      blocks_.last().reserve(std::max(at_least, buffer_chunk_size_));
    }
  }
 
  template<typename... T> void write_fstring(const char *fmt, T &&...args)
  {
    /* Format into a local buffer. */
    fmt::memory_buffer buf;
    fmt::format_to(fmt::appender(buf), fmt, std::forward<T>(args)...);
    size_t len = buf.size();
    ensure_space(len);
    VectorChar &bb = blocks_.last();
    bb.insert(bb.end(), buf.begin(), buf.end());
  }
 
  void write_bytes(Span<char> bytes);
};
 
}  // namespace blender::io::ply