// license that can be found in the LICENSE file.

package runtime

import "unsafe"

const (
	// Plan 9 environment device
	envDir = "/env/"
	// size of buffer to read from a directory
	dirBufSize = 4096
	// size of buffer to read an environment variable (may grow)
	envBufSize = 128
	// offset of the name field in a 9P directory entry - see syscall.UnmarshalDir()
	nameOffset = 39
)

	}
	for {
		n, err := ignoringEINTRIO(syscall.Read, fd.Sysfd, p)
		if err != nil {
			n = 0
			if err == syscall.EAGAIN && fd.pd.pollable() {
				if err = fd.pd.waitRead(fd.isFile); err == nil {
					continue
				}
			}
		}
		err = fd.eofError(n, err)
		return n, err
	}
}

// Pread wraps the pread system call.
func (fd *FD) Pread(p []byte, off int64) (int, error) {

	}
	defer Close(fd)

	n, e := Pread(fd, b[:], 0)

	if e != nil {
		return 0, e
	}

	m := 0
	for ; m < n && b[m] == ' '; m++ {
	}

	return atoi(b[m : n-1]), nil
}

func Getpid() (pid int) {
	n, _ := readnum("#c/pid")
	return int(n)
}

func Getppid() (ppid int) {
	n, _ := readnum("#c/ppid")
	return int(n)
}

func Read(fd int, p []byte) (n int, err error) {

	}
	return f.file.close()
}

// read reads up to len(b) bytes from the File.
// It returns the number of bytes read and an error, if any.
func (f *File) read(b []byte) (n int, err error) {
	n, err = f.pfd.Read(b)
	runtime.KeepAlive(f)
	return n, err
}

// pread reads len(b) bytes from the File starting at byte offset off.
// It returns the number of bytes read and the error, if any.

	return int(n)
}

func Getppid() (ppid int) {
	n, _ := readnum("#c/ppid")
	return int(n)
}

func Read(fd int, p []byte) (n int, err error) {
	return Pread(fd, p, -1)
}

func Write(fd int, p []byte) (n int, err error) {
	if faketime && (fd == 1 || fd == 2) {
		n = faketimeWrite(fd, p)
		if n < 0 {
			return 0, ErrorString("error")
		}
		return n, nil
	}

	return Pwrite(fd, p, -1)

  delete posix_file;
}

static int64_t Read(const TF_RandomAccessFile* file, uint64_t offset, size_t n,
                    char* buffer, TF_Status* status) {
  auto posix_file = static_cast<PosixFile*>(file->plugin_file);
  char* dst = buffer;
  int64_t read = 0;

  while (n > 0) {
    // Some platforms, notably macs, throw `EINVAL` if `pread` is asked to read
    // more than fits in a 32-bit integer.

}

// pread reads len(b) bytes from the File starting at byte offset off.
// It returns the number of bytes read and the error, if any.
// EOF is signaled by a zero count with err set to nil.
func (f *File) pread(b []byte, off int64) (n int, err error) {
	if err := f.readLock(); err != nil {
		return 0, err
	}
	defer f.readUnlock()
	n, e := fixCount(syscall.Pread(f.fd, b, off))
	if n == 0 && len(b) > 0 && e == nil {

			break
		}
		b[i] = x
	}
	fd.readbyteOffset += i
	return i, nil
}

// Pread emulates the Unix pread system call.
func (fd *FD) Pread(b []byte, off int64) (int, error) {
	if fd.kind == kindPipe {
		// Pread does not work with pipes
		return 0, syscall.ESPIPE
	}
	// Call incref, not readLock, because since pread specifies the
	// offset it is independent from other reads.
	if err := fd.incref(); err != nil {

	}
	return 0 // success
}

//go:nosplit
func semawakeup(mp *m) {
	plan9_semrelease(&mp.waitsemacount, 1)
}

//go:nosplit
func read(fd int32, buf unsafe.Pointer, n int32) int32 {
	return pread(fd, buf, n, -1)
}

//go:nosplit
func write1(fd uintptr, buf unsafe.Pointer, n int32) int32 {
	return pwrite(int32(fd), buf, n, -1)
}

//sys	Iopl(level int) (err error)
//sys	Lchown(path string, uid int, gid int) (err error)
//sys	Listen(s int, n int) (err error)
//sys	Lstat(path string, stat *Stat_t) (err error)
//sys	Pause() (err error)
//sys	pread(fd int, p []byte, offset int64) (n int, err error) = SYS_PREAD64
//sys	pwrite(fd int, p []byte, offset int64) (n int, err error) = SYS_PWRITE64
//sys	Renameat(olddirfd int, oldpath string, newdirfd int, newpath string) (err error)