Luna/file_reader
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Now the design is fully done for errors as values #2

Merged
Luna merged 1 commit from detached into main 2025-07-24 05:08:03 +02:00
Conversation 0 Commits 1 Files changed 1 +60 -20
1 changed files with 60 additions and 20 deletions
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80
src/file_read.h
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@ -13,7 +13,9 @@ namespace file_reader
READ_CORRECT, //read was as expected
READ_INCOMPLETE, //read is incomplete (probably because of the file ending)
READ_FILE_ENDED, //cannot read because there's not more file to read
READ_FAILED
READ_FAILED,
FILE_DOESNT_EXIST,
FILE_LSEEK_FAIL
};
class file_reader
@ -39,29 +41,14 @@ namespace file_reader
file_size_remaining = file_size;
}
file_reader(std::string path)
file_reader()
{
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");
}
fd = 0;
buf.size = 0;
buf.allocated = 0;
buf.data = nullptr;
file_size = lseek(fd, 0, SEEK_END);
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_size_remaining = 0;
file_size = 0;
}
file_reader(const file_reader&) = delete;
@ -71,6 +58,33 @@ namespace file_reader
close(fd);
}
int extra_size = 0;
std::expected<size_t, RESULT> open_file(const std::string &path)
{
fd = open(path.c_str(), O_RDONLY);
if (fd == -1)
{
std::println("Error opening the file {}", strerror(errno));
return std::unexpected(RESULT::FILE_DOESNT_EXIST);
}
buf.size = 0;
buf.allocated = 0;
buf.data = nullptr;
file_size = lseek(fd, 0, SEEK_END);
if (file_size == -1)
{
std::println("lseek failed {}", strerror(errno));
return std::unexpected(RESULT::FILE_LSEEK_FAIL);
}
if (lseek(fd, 0, SEEK_SET) == -1)
{
std::println("lseek failed {}", strerror(errno));
return std::unexpected(RESULT::FILE_LSEEK_FAIL);
}
file_size_remaining = file_size;
return file_size;
}
template<typename ...T>
std::expected<size_t, RESULT> read_from_tuple(std::tuple<T...> &in)
{
@ -198,3 +212,29 @@ namespace file_reader
off_t file_size_remaining;
};
}
template <>
struct std::formatter<file_reader::RESULT>
{
constexpr auto parse(std::format_parse_context& ctx) {
return ctx.begin();
}
auto format(const file_reader::RESULT& id, std::format_context& ctx) const
{
if (id == file_reader::RESULT::FILE_DOESNT_EXIST)
return std::format_to(ctx.out(), "{}", "File doesn't exist");
if (id == file_reader::RESULT::READ_FAILED)
return std::format_to(ctx.out(), "{}", "Read failed");
if (id == file_reader::RESULT::FILE_LSEEK_FAIL)
return std::format_to(ctx.out(), "{}", "File lseek failed");
if (id == file_reader::RESULT::READ_CORRECT)
return std::format_to(ctx.out(), "{}", "Read correct");
if (id == file_reader::RESULT::READ_FILE_ENDED)
return std::format_to(ctx.out(), "{}", "File ended");
if (id == file_reader::RESULT::READ_INCOMPLETE)
return std::format_to(ctx.out(), "{}", "Read incomplete");
return std::format_to(ctx.out(), "{}", "Unknown error");
}
};