Luna/file_reader
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Made project more solid, made deserialiser do incomplete buffer read, made file_reader non copyable, updated test.cpp

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This commit is contained in:
Luna 2025-07-03 19:12:21 +02:00
parent ceb65deca8
commit 02b593c237
3 changed files with 75 additions and 12 deletions
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10
examples/test.cpp
View file

@ -11,8 +11,18 @@ int main()
t.allocated = 0;
t.size = 10;
auto tup = std::make_tuple(t);
auto tup2 = std::make_tuple(t);
auto tup3 = std::make_tuple(t);
auto res = a.read_from_tuple(tup);
auto re2 = a.read_from_tuple(tup2);
auto re3 = a.read_from_tuple(tup3);
if (res.second == READ_CORRECT)
std::println("{}", std::get<0>(tup).data);
if (re2.second == READ_CORRECT)
std::println("{}", std::get<0>(tup2).data);
if (re3.second == READ_CORRECT)
std::println("{}", std::get<0>(tup3).data);
if (re3.second == READ_INCOMPLETE)
std::println("incomplete read with size {} {}", re3.first, std::get<0>(tup3).data);
}

9
src/file_deserialising.h
View file

@ -92,12 +92,19 @@ struct read_var
static void call(T& val, parsing_buffer* v)
{
int size = 0;
if (typeid(T) == typeid(buffer))
if constexpr (typeid(T) == typeid(buffer))
size = val.size;
else
size = sizeof(T);
if (size + v->consumed_size > v->buf.size)
{
if constexpr (typeid(T) == typeid(buffer))
{
val.size = v->buf.size;
}
else
return ;
}
read_type<T>(val, v->point);
v->point += size;
v->consumed_size += size;

60
src/file_read.h
View file

@ -22,21 +22,51 @@ class file_reader
buf.allocated = 0;
buf.data = nullptr;
file_size = lseek(fd, 0, SEEK_END);
lseek(fd, 0, SEEK_SET);
if (file_size == -1)
{
std::println("lseek failed {}", strerror(errno));
throw std::runtime_error("lseek failed");
}
if (lseek(fd, 0, SEEK_SET) == -1)
{
std::println("lseek failed {}", strerror(errno));
throw std::runtime_error("lseek failed");
}
file_size_remaining = file_size;
}
file_reader(std::string path)
{
fd = open(path.c_str(), O_RDONLY);
if (fd == -1)
{
std::println("Error opening the file {}", strerror(errno));
throw std::runtime_error("Error opening file");
}
buf.size = 0;
buf.allocated = 0;
buf.data = nullptr;
file_size = lseek(fd, 0, SEEK_END);
lseek(fd, 0, SEEK_SET);
if (file_size == -1)
{
std::println("lseek failed {}", strerror(errno));
throw std::runtime_error("lseek failed");
}
if (lseek(fd, 0, SEEK_SET) == -1)
{
std::println("lseek failed {}", strerror(errno));
throw std::runtime_error("lseek failed");
}
file_size_remaining = file_size;
}
file_reader(const file_reader&) = delete;
file_reader & operator=(const file_reader &) = delete;
~file_reader()
{
close(fd);
}
template<typename ...T>
std::pair<size_t, RESULT> read_from_tuple(std::tuple<T...> &in)
{
@ -46,6 +76,7 @@ class file_reader
constexpr std::size_t size_tuple = sizeof...(T);
int size = 0;
int extra_size = 0;
size_t total_read_size = 0;
const_for_<size_tuple>([&](auto i)
{
if constexpr (typeid(std::get<i.value>(in)) == typeid(buffer))
@ -65,15 +96,29 @@ class file_reader
ret = READ_INCOMPLETE;
}
char *new_read = (char *)calloc(size + extra_size, sizeof(char));
size_t res = read(fd, new_read, size + extra_size);
if (res != size + extra_size)
total_read_size = size + extra_size;
size_t read_done = 0;
size_t res = 0;
while (read_done != size + extra_size)
{
res = read(fd, &new_read[read_done], (size + extra_size) - read_done);
if (res == -1)
{
free(new_read);
std::println("Read error {}", strerror(errno));
throw std::runtime_error("Read failed!");
}
buf.write(new_read, size + extra_size);
file_size_remaining -= size + extra_size;
if (res == 0)
{
if (read_done != size + extra_size)
ret = READ_INCOMPLETE;
total_read_size = read_done;
break;
}
read_done += res;
}
buf.write(new_read, total_read_size);
file_size_remaining -= total_read_size;
free(new_read);
}
parsing_buffer par_buf(buf);
@ -81,8 +126,9 @@ class file_reader
par_buf.consumed_size = 0;
read_comp(size_tuple, par_buf, in);
buf.remove(0, size);
return std::make_pair(size + extra_size, ret);
return std::make_pair(total_read_size, ret);
}
private:
buffer buf;
int fd;
off_t file_size;