msgpack EXT issue

main.cpp

#include <iostream>
#include <msgpack.hpp>
#include <unistd.h>

static const std::size_t MSGPACK_CHUNK_SIZE = 8 * 1024; // 64KB works fine!

void assert_key_exists(const msgpack::object &object, const char string[6]);
bool equal_to_symbol_p(const msgpack::object &object, const std::string &string);
void dump_map(const msgpack::object &object);

static const int SYMBOL_EXT_CODE = 0x00;

int main() {

//  auto src = "simple_no_ext.mp";
  auto src = "simple.mp";
  auto file = fopen(src, "r");
  if (file == NULL) {
    perror(src);
    exit(1);
  }
  auto fd = fileno(file);

  msgpack::unpacker unpacker;
  msgpack::object_handle result;

  size_t in = 0;
  for (;;) {
    unpacker.reserve_buffer(MSGPACK_CHUNK_SIZE);
    auto input_size = read(fd, unpacker.buffer(), unpacker.buffer_capacity());
    if (input_size < 0) {
      exit(1);
    }
    in += input_size;
    unpacker.buffer_consumed(static_cast<std::size_t>(input_size));

    if (unpacker.next(result)) {
      assert_key_exists(result.get(), "input");
      assert_key_exists(result.get(), "sources");
      break;
    }
  }
  fprintf(stdout, "Read %zu bytes\n", in);
  dump_map(result.get());
}

void dump_map(const msgpack::object &object) {
  fprintf(stdout, "\n\nThe map has %d elements: \n", object.via.map.size);
  for (int i = 0; i < object.via.map.size; i++) {
    auto ext = object.via.map.ptr[i].key.via.ext;
    fprintf(stdout, " + key '%s'\n", std::string(ext.data(), ext.size).c_str());
  }
}

void assert_key_exists(const msgpack::object &object, const char *key) {
  if (object.type == msgpack::type::MAP) {

    for (auto &element : object.via.map) {
      if (equal_to_symbol_p(element.key, key)) {
        fprintf(stdout, "Did find key '%s'\n", key);
        return;
      }
    }
  }
  fprintf(stderr, "Did NOT find key '%s'\n", key);
}

bool equal_to_symbol_p(const msgpack::object &object, const std::string &string) {
//  if (object.type != msgpack::type::STR) {
  if (object.type != msgpack::type::EXT) {
    return false;
  }

//  auto ext = object.via.str;
  msgpack::object_ext ext = object.via.ext;
  if (ext.type() != SYMBOL_EXT_CODE) {
    return false;
  }

//  return ext.size == string.length() && std::equal(ext.ptr, ext.ptr + ext.size, string.begin());
  return ext.size == string.length() && std::equal(ext.data(), ext.data() + ext.size, string.begin());
}

simple.mp

simple_no_ext.mp