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chacha20stream/src/ffi/cookie.rs

115 lines
2.6 KiB

#![allow(non_camel_case_types)]
use super::*;
use std::{
slice,
};
use libc::{
c_void,
c_char,
c_int,
off64_t,
ssize_t,
size_t,
FILE,
};
//TODO: Remove `wrapper.c`, implement it in Rust here
type cookie_read_function_t = Option<extern "C" fn (cookie: *mut c_void, buf: *mut c_char , size: size_t) -> ssize_t>;
type cookie_write_function_t = Option<extern "C" fn (cookie: *mut c_void, buf: *const c_char, size: size_t) -> ssize_t>;
type cookie_seek_function_t = Option<extern "C" fn (cookie: *mut c_void, offset: *mut off64_t, whence: c_int) -> c_int>;
type cookie_close_function_t = Option<extern "C" fn (cookie: *mut c_void) -> c_int>;
const _: [u8; 8] = [0u8; std::mem::size_of::<cookie_read_function_t>()];
// `fopencookie` API
#[derive(Debug, Clone, Copy, Default)]
#[repr(C)]
struct cookie_io_functions_t
{
read: cookie_read_function_t,
write: cookie_write_function_t,
seek: cookie_seek_function_t,
close: cookie_close_function_t,
}
extern "C" {
fn fopencookie(cookie: *mut c_void, mode: *const c_char, funcs: cookie_io_functions_t) -> *mut FILE;
}
#[inline(always)] unsafe fn ref_cookie<'a>(cookie: *mut c_void) -> Option<&'a mut CSink>
{
if cookie.is_null() {
None
} else {
Some(&mut *(cookie as *mut CSink))
}
}
macro_rules! unwrap {
(? $expr:expr, $or:expr) => {
if let Some(val) = $expr {
val
} else {
return $or;
}
};
}
extern "C" fn read(_cookie: *mut c_void, _buf: *mut c_char, _size: size_t) -> ssize_t
{
-1
}
extern "C" fn write(cookie: *mut c_void, buf: *const c_char, size: size_t) -> ssize_t
{
//Remember: Cannot return -1 here
no_unwind!({
if buf.is_null() {
return 0;
}
let sink = unwrap!(? unsafe { ref_cookie(cookie) }, 0);
let buf = unsafe { slice::from_raw_parts(buf as *const u8, size) };
match sink.sink.write(buf) {
Ok(n) if n < ssize_t::MAX as usize => n as ssize_t,
Err(_er) => {
//sink.last_err_code =
//sink.last_err = Some(
0
},
_ => {
// TODO
// Write succeeded, but wrote more than `isize::MAX`.
0
},
}
}).unwrap_or(0)
}
extern "C" fn seek(_cookie: *mut c_void, _offset: *mut off64_t, _whence: c_int) -> c_int
{
-1
}
extern "C" fn close(cookie: *mut c_void) -> c_int
{
let sink = if cookie.is_null() {
return -1;
} else {
cookie as *mut CSink
};
let sink = unsafe { interop::take(sink) };
drop(sink);
0
}
#[inline(always)] pub unsafe fn create(raw_sink: *mut CSink) -> *mut FILE
{
fopencookie(raw_sink as *mut c_void, b"wb\0" as *const u8 as *const c_char, cookie_io_functions_t {
read: Some(read),
write: Some(write),
seek: Some(seek),
close: Some(close),
})
}