Luna/libs/libc/src/file.cpp

#include <errno.h>
#include <fcntl.h>
#include <luna.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

extern "C"
{
    int fclose(FILE* stream)
    {
        int status = close(stream->fd);
        if (status < 0)
        {
            int savederr = errno;
            free(stream); // We do not want to leak memory. man fclose(3) says that whether fclose() fails or not, any
                          // further operation on the stream results in undefined behavior. So we are free to free the
                          // stream.
            errno = savederr; // free might reset errno. We don't want that.
        }
        else { free(stream); }
        return status;
    }

    int fflush(FILE*)
    {
        return 0; // FIXME: Implement buffered IO.
    }

    FILE* fopen(const char* pathname, const char*)
    {
        int fd = open(pathname, O_RDONLY); // FIXME: Use the mode string.
        if (fd < 0) { return 0; }
        FILE* stream = (FILE*)malloc(sizeof(FILE));
        stream->fd = fd;
        return stream;
    }

    size_t fread(void* buf, size_t size, size_t nmemb, FILE* stream)
    {
        ssize_t status = read(stream->fd, buf, size * nmemb);
        if (status < 0)
            return 0; // FIXME: The manual says that fread() does not differentiate between EOF and error, and that
                      // ferror() and feof() should be called to determine such. So right now, we just mask the error,
                      // until that is implemented.
        return (size_t)status;
    }

    int fseek(FILE*, long, int)
    {
        NOT_IMPLEMENTED("fseek");
    }

    long ftell(FILE*)
    {
        NOT_IMPLEMENTED("ftell");
    }

    size_t fwrite(const void*, size_t, size_t, FILE*)
    {
        NOT_IMPLEMENTED("fwrite");
    }

    void setbuf(FILE*, char*)
    {
        NOT_IMPLEMENTED("setbuf");
    }
}