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v/vlib/os/file.c.v

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module os
pub struct File {
cfile voidptr // Using void* instead of FILE*
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pub:
fd int
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pub mut:
is_opened bool
}
struct FileInfo {
name string
size int
}
fn C.fseeko(&C.FILE, u64, int) int
fn C._fseeki64(&C.FILE, u64, int) int
fn C.getc(&C.FILE) int
// open_file can be used to open or create a file with custom flags and permissions and returns a `File` object.
pub fn open_file(path string, mode string, options ...int) ?File {
mut flags := 0
for m in mode {
match m {
`w` { flags |= o_create | o_trunc }
`a` { flags |= o_create | o_append }
`r` { flags |= o_rdonly }
`b` { flags |= o_binary }
`s` { flags |= o_sync }
`n` { flags |= o_nonblock }
`c` { flags |= o_noctty }
`+` { flags |= o_rdwr }
else {}
}
}
if mode == 'r+' {
flags = o_rdwr
}
if mode == 'w' {
flags = o_wronly | o_create | o_trunc
}
if mode == 'a' {
flags = o_wronly | o_create | o_append
}
mut permission := 0o666
if options.len > 0 {
permission = options[0]
}
$if windows {
if permission < 0o600 {
permission = 0x0100
} else {
permission = 0x0100 | 0x0080
}
}
mut p := path
$if windows {
p = path.replace('/', '\\')
}
fd := C.open(&char(p.str), flags, permission)
if fd == -1 {
return error(posix_get_error_msg(C.errno))
}
cfile := C.fdopen(fd, &char(mode.str))
if isnil(cfile) {
return error('Failed to open or create file "$path"')
}
return File{
cfile: cfile
fd: fd
is_opened: true
}
}
// open tries to open a file for reading and returns back a read-only `File` object.
pub fn open(path string) ?File {
/*
$if linux {
$if !android {
fd := C.syscall(sys_open, path.str, 511)
if fd == -1 {
return error('failed to open file "$path"')
}
return File{
fd: fd
is_opened: true
}
}
}
*/
cfile := vfopen(path, 'rb')?
fd := fileno(cfile)
return File{
cfile: cfile
fd: fd
is_opened: true
}
}
// create creates or opens a file at a specified location and returns a write-only `File` object.
pub fn create(path string) ?File {
/*
// Note: android/termux/bionic is also a kind of linux,
// but linux syscalls there sometimes fail,
// while the libc version should work.
$if linux {
$if !android {
//$if macos {
// fd = C.syscall(398, path.str, 0x601, 0x1b6)
//}
//$if linux {
fd = C.syscall(sys_creat, path.str, 511)
//}
if fd == -1 {
return error('failed to create file "$path"')
}
file = File{
fd: fd
is_opened: true
}
return file
}
}
*/
cfile := vfopen(path, 'wb')?
fd := fileno(cfile)
return File{
cfile: cfile
fd: fd
is_opened: true
}
}
// stdin - return an os.File for stdin, so that you can use .get_line on it too.
pub fn stdin() File {
return File{
fd: 0
cfile: C.stdin
is_opened: true
}
}
// stdout - return an os.File for stdout
pub fn stdout() File {
return File{
fd: 1
cfile: C.stdout
is_opened: true
}
}
// stderr - return an os.File for stderr
pub fn stderr() File {
return File{
fd: 2
cfile: C.stderr
is_opened: true
}
}
// read implements the Reader interface.
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pub fn (f &File) read(mut buf []u8) ?int {
if buf.len == 0 {
return 0
}
nbytes := fread(buf.data, 1, buf.len, f.cfile)?
return nbytes
}
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// **************************** Write ops ***************************
// write implements the Writer interface.
// It returns how many bytes were actually written.
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pub fn (mut f File) write(buf []u8) ?int {
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if !f.is_opened {
return error_file_not_opened()
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}
/*
$if linux {
$if !android {
res := C.syscall(sys_write, f.fd, s.str, s.len)
return res
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}
}
*/
written := int(C.fwrite(buf.data, 1, buf.len, f.cfile))
if written == 0 && buf.len != 0 {
return error('0 bytes written')
}
return written
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}
// writeln writes the string `s` into the file, and appends a \n character.
// It returns how many bytes were written, including the \n character.
pub fn (mut f File) writeln(s string) ?int {
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if !f.is_opened {
return error_file_not_opened()
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}
/*
$if linux {
$if !android {
snl := s + '\n'
C.syscall(sys_write, f.fd, snl.str, snl.len)
return
}
}
*/
// TODO perf
written := int(C.fwrite(s.str, 1, s.len, f.cfile))
if written == 0 && s.len != 0 {
return error('0 bytes written')
}
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x := C.fputs(c'\n', f.cfile)
if x < 0 {
return error('could not add newline')
}
return written + 1
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}
// write_string writes the string `s` into the file
// It returns how many bytes were actually written.
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pub fn (mut f File) write_string(s string) ?int {
unsafe { f.write_full_buffer(s.str, usize(s.len))? }
return s.len
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}
// write_to implements the RandomWriter interface.
// It returns how many bytes were actually written.
// It resets the seek position to the end of the file.
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pub fn (mut f File) write_to(pos u64, buf []u8) ?int {
if !f.is_opened {
return error_file_not_opened()
}
$if x64 {
$if windows {
C._fseeki64(f.cfile, pos, C.SEEK_SET)
res := int(C.fwrite(buf.data, 1, buf.len, f.cfile))
if res == 0 && buf.len != 0 {
return error('0 bytes written')
}
C._fseeki64(f.cfile, 0, C.SEEK_END)
return res
} $else {
C.fseeko(f.cfile, pos, C.SEEK_SET)
res := int(C.fwrite(buf.data, 1, buf.len, f.cfile))
if res == 0 && buf.len != 0 {
return error('0 bytes written')
}
C.fseeko(f.cfile, 0, C.SEEK_END)
return res
}
}
$if x32 {
C.fseek(f.cfile, pos, C.SEEK_SET)
res := int(C.fwrite(buf.data, 1, buf.len, f.cfile))
if res == 0 && buf.len != 0 {
return error('0 bytes written')
}
C.fseek(f.cfile, 0, C.SEEK_END)
return res
}
return error('Could not write to file')
}
// write_ptr writes `size` bytes to the file, starting from the address in `data`.
// Note: write_ptr is unsafe and should be used carefully, since if you pass invalid
// pointers to it, it will cause your programs to segfault.
[unsafe]
pub fn (mut f File) write_ptr(data voidptr, size int) int {
return int(C.fwrite(data, 1, size, f.cfile))
}
// write_full_buffer writes a whole buffer of data to the file, starting from the
// address in `buffer`, no matter how many tries/partial writes it would take.
[unsafe]
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pub fn (mut f File) write_full_buffer(buffer voidptr, buffer_len usize) ? {
if buffer_len <= usize(0) {
return
}
if !f.is_opened {
return error_file_not_opened()
}
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mut ptr := &u8(buffer)
mut remaining_bytes := i64(buffer_len)
for remaining_bytes > 0 {
unsafe {
x := i64(C.fwrite(ptr, 1, remaining_bytes, f.cfile))
ptr += x
remaining_bytes -= x
if x <= 0 {
return error('C.fwrite returned 0')
}
}
}
}
// write_ptr_at writes `size` bytes to the file, starting from the address in `data`,
// at byte offset `pos`, counting from the start of the file (pos 0).
// Note: write_ptr_at is unsafe and should be used carefully, since if you pass invalid
// pointers to it, it will cause your programs to segfault.
[unsafe]
pub fn (mut f File) write_ptr_at(data voidptr, size int, pos u64) int {
$if x64 {
$if windows {
C._fseeki64(f.cfile, pos, C.SEEK_SET)
res := int(C.fwrite(data, 1, size, f.cfile))
C._fseeki64(f.cfile, 0, C.SEEK_END)
return res
} $else {
C.fseeko(f.cfile, pos, C.SEEK_SET)
res := int(C.fwrite(data, 1, size, f.cfile))
C.fseeko(f.cfile, 0, C.SEEK_END)
return res
}
}
$if x32 {
C.fseek(f.cfile, pos, C.SEEK_SET)
res := int(C.fwrite(data, 1, size, f.cfile))
C.fseek(f.cfile, 0, C.SEEK_END)
return res
}
return 0
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}
// **************************** Read ops ***************************
// fread wraps C.fread and handles error and end-of-file detection.
fn fread(ptr voidptr, item_size int, items int, stream &C.FILE) ?int {
nbytes := int(C.fread(ptr, item_size, items, stream))
// If no bytes were read, check for errors and end-of-file.
if nbytes <= 0 {
// If fread encountered end-of-file return the none error. Note that fread
// may read data and encounter the end-of-file, but we shouldn't return none
// in that case which is why we only check for end-of-file if no data was
// read. The caller will get none on their next call because there will be
// no data available and the end-of-file will be encountered again.
if C.feof(stream) != 0 {
return none
}
// If fread encountered an error, return it. Note that fread and ferror do
// not tell us what the error was, so we can't return anything more specific
// than there was an error. This is because fread and ferror do not set
// errno.
if C.ferror(stream) != 0 {
return error('file read error')
}
}
return nbytes
}
// read_bytes reads bytes from the beginning of the file.
// Utility method, same as .read_bytes_at(size, 0).
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pub fn (f &File) read_bytes(size int) []u8 {
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return f.read_bytes_at(size, 0)
}
// read_bytes_at reads `size` bytes at the given position in the file.
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pub fn (f &File) read_bytes_at(size int, pos u64) []u8 {
mut arr := []u8{len: size}
nreadbytes := f.read_bytes_into(pos, mut arr) or {
// return err
return []
}
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return arr[0..nreadbytes]
}
// read_bytes_into_newline reads from the beginning of the file into the provided buffer.
// Each consecutive call on the same file continues reading where it previously ended.
// A read call is either stopped, if the buffer is full, a newline was read or EOF.
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pub fn (f &File) read_bytes_into_newline(mut buf []u8) ?int {
if buf.len == 0 {
return error(@FN + ': `buf.len` == 0')
}
newline := 10
mut c := 0
mut buf_ptr := 0
mut nbytes := 0
stream := &C.FILE(f.cfile)
for (buf_ptr < buf.len) {
c = C.getc(stream)
match c {
C.EOF {
if C.feof(stream) != 0 {
return nbytes
}
if C.ferror(stream) != 0 {
return error('file read error')
}
}
newline {
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buf[buf_ptr] = u8(c)
nbytes++
return nbytes
}
else {
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buf[buf_ptr] = u8(c)
buf_ptr++
nbytes++
}
}
}
return nbytes
}
// read_bytes_into fills `buf` with bytes at the given position in the file.
// `buf` *must* have length greater than zero.
// Returns the number of read bytes, or an error.
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pub fn (f &File) read_bytes_into(pos u64, mut buf []u8) ?int {
if buf.len == 0 {
return error(@FN + ': `buf.len` == 0')
}
$if x64 {
$if windows {
// Note: fseek errors if pos == os.file_size, which we accept
C._fseeki64(f.cfile, pos, C.SEEK_SET)
nbytes := fread(buf.data, 1, buf.len, f.cfile)?
$if debug {
C._fseeki64(f.cfile, 0, C.SEEK_SET)
}
return nbytes
} $else {
C.fseeko(f.cfile, pos, C.SEEK_SET)
nbytes := fread(buf.data, 1, buf.len, f.cfile)?
$if debug {
C.fseeko(f.cfile, 0, C.SEEK_SET)
}
return nbytes
}
}
$if x32 {
C.fseek(f.cfile, pos, C.SEEK_SET)
nbytes := fread(buf.data, 1, buf.len, f.cfile)?
$if debug {
C.fseek(f.cfile, 0, C.SEEK_SET)
}
return nbytes
}
return error('Could not read file')
}
// read_from implements the RandomReader interface.
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pub fn (f &File) read_from(pos u64, mut buf []u8) ?int {
if buf.len == 0 {
return 0
}
$if x64 {
$if windows {
C._fseeki64(f.cfile, pos, C.SEEK_SET)
} $else {
C.fseeko(f.cfile, pos, C.SEEK_SET)
}
nbytes := fread(buf.data, 1, buf.len, f.cfile)?
return nbytes
}
$if x32 {
C.fseek(f.cfile, pos, C.SEEK_SET)
nbytes := fread(buf.data, 1, buf.len, f.cfile)?
return nbytes
}
return error('Could not read file')
}
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// read_into_ptr reads at most max_size bytes from the file and writes it into ptr.
// Returns the amount of bytes read or an error.
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pub fn (f &File) read_into_ptr(ptr &u8, max_size int) ?int {
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return fread(ptr, 1, max_size, f.cfile)
}
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// **************************** Utility ops ***********************
// flush writes any buffered unwritten data left in the file stream.
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pub fn (mut f File) flush() {
if !f.is_opened {
return
}
C.fflush(f.cfile)
}
pub struct FileNotOpenedError {
Error
}
pub fn (err FileNotOpenedError) msg() string {
return 'os: file not opened'
}
pub struct SizeOfTypeIs0Error {
Error
}
pub fn (err SizeOfTypeIs0Error) msg() string {
return 'os: size of type is 0'
}
fn error_file_not_opened() IError {
return IError(&FileNotOpenedError{})
}
fn error_size_of_type_0() IError {
return IError(&SizeOfTypeIs0Error{})
}
// read_struct reads a single struct of type `T`
pub fn (mut f File) read_struct<T>(mut t T) ? {
if !f.is_opened {
return error_file_not_opened()
}
tsize := int(sizeof(*t))
if tsize == 0 {
return error_size_of_type_0()
}
nbytes := fread(t, 1, tsize, f.cfile)?
if nbytes != tsize {
return error_with_code('incomplete struct read', nbytes)
}
}
// read_struct_at reads a single struct of type `T` at position specified in file
pub fn (mut f File) read_struct_at<T>(mut t T, pos u64) ? {
if !f.is_opened {
return error_file_not_opened()
}
tsize := int(sizeof(*t))
if tsize == 0 {
return error_size_of_type_0()
}
mut nbytes := 0
$if x64 {
$if windows {
C._fseeki64(f.cfile, pos, C.SEEK_SET)
nbytes = fread(t, 1, tsize, f.cfile)?
C._fseeki64(f.cfile, 0, C.SEEK_END)
} $else {
C.fseeko(f.cfile, pos, C.SEEK_SET)
nbytes = fread(t, 1, tsize, f.cfile)?
C.fseeko(f.cfile, 0, C.SEEK_END)
}
}
$if x32 {
C.fseek(f.cfile, pos, C.SEEK_SET)
nbytes = fread(t, 1, tsize, f.cfile)?
C.fseek(f.cfile, 0, C.SEEK_END)
}
if nbytes != tsize {
return error_with_code('incomplete struct read', nbytes)
}
}
// read_raw reads and returns a single instance of type `T`
pub fn (mut f File) read_raw<T>() ?T {
if !f.is_opened {
return error_file_not_opened()
}
tsize := int(sizeof(T))
if tsize == 0 {
return error_size_of_type_0()
}
mut t := T{}
nbytes := fread(&t, 1, tsize, f.cfile)?
if nbytes != tsize {
return error_with_code('incomplete struct read', nbytes)
}
return t
}
// read_raw_at reads and returns a single instance of type `T` starting at file byte offset `pos`
pub fn (mut f File) read_raw_at<T>(pos u64) ?T {
if !f.is_opened {
return error_file_not_opened()
}
tsize := int(sizeof(T))
if tsize == 0 {
return error_size_of_type_0()
}
mut nbytes := 0
mut t := T{}
$if x64 {
$if windows {
if C._fseeki64(f.cfile, pos, C.SEEK_SET) != 0 {
return error(posix_get_error_msg(C.errno))
}
nbytes = fread(&t, 1, tsize, f.cfile)?
if C._fseeki64(f.cfile, 0, C.SEEK_END) != 0 {
return error(posix_get_error_msg(C.errno))
}
} $else {
if C.fseeko(f.cfile, pos, C.SEEK_SET) != 0 {
return error(posix_get_error_msg(C.errno))
}
nbytes = fread(&t, 1, tsize, f.cfile)?
if C.fseeko(f.cfile, 0, C.SEEK_END) != 0 {
return error(posix_get_error_msg(C.errno))
}
}
}
$if x32 {
if C.fseek(f.cfile, pos, C.SEEK_SET) != 0 {
return error(posix_get_error_msg(C.errno))
}
nbytes = fread(&t, 1, tsize, f.cfile)?
if C.fseek(f.cfile, 0, C.SEEK_END) != 0 {
return error(posix_get_error_msg(C.errno))
}
}
if nbytes != tsize {
return error_with_code('incomplete struct read', nbytes)
}
return t
}
// write_struct writes a single struct of type `T`
pub fn (mut f File) write_struct<T>(t &T) ? {
if !f.is_opened {
return error_file_not_opened()
}
tsize := int(sizeof(T))
if tsize == 0 {
return error_size_of_type_0()
}
C.errno = 0
nbytes := int(C.fwrite(t, 1, tsize, f.cfile))
if C.errno != 0 {
return error(posix_get_error_msg(C.errno))
}
if nbytes != tsize {
return error_with_code('incomplete struct write', nbytes)
}
}
// write_struct_at writes a single struct of type `T` at position specified in file
pub fn (mut f File) write_struct_at<T>(t &T, pos u64) ? {
if !f.is_opened {
return error_file_not_opened()
}
tsize := int(sizeof(T))
if tsize == 0 {
return error_size_of_type_0()
}
C.errno = 0
mut nbytes := 0
$if x64 {
$if windows {
C._fseeki64(f.cfile, pos, C.SEEK_SET)
nbytes = int(C.fwrite(t, 1, tsize, f.cfile))
C._fseeki64(f.cfile, 0, C.SEEK_END)
} $else {
C.fseeko(f.cfile, pos, C.SEEK_SET)
nbytes = int(C.fwrite(t, 1, tsize, f.cfile))
C.fseeko(f.cfile, 0, C.SEEK_END)
}
}
$if x32 {
C.fseek(f.cfile, pos, C.SEEK_SET)
nbytes = int(C.fwrite(t, 1, tsize, f.cfile))
C.fseek(f.cfile, 0, C.SEEK_END)
}
if C.errno != 0 {
return error(posix_get_error_msg(C.errno))
}
if nbytes != tsize {
return error_with_code('incomplete struct write', nbytes)
}
}
// TODO `write_raw[_at]` implementations are copy-pasted from `write_struct[_at]`
// write_raw writes a single instance of type `T`
pub fn (mut f File) write_raw<T>(t &T) ? {
if !f.is_opened {
return error_file_not_opened()
}
tsize := int(sizeof(T))
if tsize == 0 {
return error_size_of_type_0()
}
C.errno = 0
nbytes := int(C.fwrite(t, 1, tsize, f.cfile))
if C.errno != 0 {
return error(posix_get_error_msg(C.errno))
}
if nbytes != tsize {
return error_with_code('incomplete struct write', nbytes)
}
}
// write_raw_at writes a single instance of type `T` starting at file byte offset `pos`
pub fn (mut f File) write_raw_at<T>(t &T, pos u64) ? {
if !f.is_opened {
return error_file_not_opened()
}
tsize := int(sizeof(T))
if tsize == 0 {
return error_size_of_type_0()
}
mut nbytes := 0
$if x64 {
$if windows {
if C._fseeki64(f.cfile, pos, C.SEEK_SET) != 0 {
return error(posix_get_error_msg(C.errno))
}
nbytes = int(C.fwrite(t, 1, tsize, f.cfile))
if C.errno != 0 {
return error(posix_get_error_msg(C.errno))
}
if C._fseeki64(f.cfile, 0, C.SEEK_END) != 0 {
return error(posix_get_error_msg(C.errno))
}
} $else {
if C.fseeko(f.cfile, pos, C.SEEK_SET) != 0 {
return error(posix_get_error_msg(C.errno))
}
nbytes = int(C.fwrite(t, 1, tsize, f.cfile))
if C.errno != 0 {
return error(posix_get_error_msg(C.errno))
}
if C.fseeko(f.cfile, 0, C.SEEK_END) != 0 {
return error(posix_get_error_msg(C.errno))
}
}
}
$if x32 {
if C.fseek(f.cfile, pos, C.SEEK_SET) != 0 {
return error(posix_get_error_msg(C.errno))
}
nbytes = int(C.fwrite(t, 1, tsize, f.cfile))
if C.errno != 0 {
return error(posix_get_error_msg(C.errno))
}
if C.fseek(f.cfile, 0, C.SEEK_END) != 0 {
return error(posix_get_error_msg(C.errno))
}
}
if nbytes != tsize {
return error_with_code('incomplete struct write', nbytes)
}
}
pub enum SeekMode {
start
current
end
}
// seek moves the file cursor (if any) associated with a file
// to a new location, offset `pos` bytes from the origin. The origin
// is dependent on the `mode` and can be:
// .start -> the origin is the start of the file
// .current -> the current position/cursor in the file
// .end -> the end of the file
// If the file is not seek-able, or an error occures, the error will
// be returned to the caller.
// A successful call to the fseek() function clears the end-of-file
// indicator for the file.
pub fn (mut f File) seek(pos i64, mode SeekMode) ? {
if !f.is_opened {
return error_file_not_opened()
}
whence := int(mode)
mut res := 0
$if x64 {
$if windows {
res = C._fseeki64(f.cfile, pos, whence)
} $else {
res = C.fseeko(f.cfile, pos, whence)
}
}
$if x32 {
res = C.fseek(f.cfile, pos, whence)
}
if res == -1 {
return error(posix_get_error_msg(C.errno))
}
}
// tell will return the current offset of the file cursor measured from
// the start of the file, in bytes. It is complementary to seek, i.e.
// you can use the return value as the `pos` parameter to .seek( pos, .start ),
// so that your next read will happen from the same place.
pub fn (f &File) tell() ?i64 {
if !f.is_opened {
return error_file_not_opened()
}
pos := C.ftell(f.cfile)
if pos == -1 {
return error(posix_get_error_msg(C.errno))
}
return pos
}