On 04/10/2012 05:16 AM, Alexander Stavonin wrote:
Hi all, it's again me.
I have a C function returns array of null terminated strings. And I need to
convert it to an Rust string type.
C function declaration:
const char** func();
Rust code:
native mod c {
fn func() -> **libc::c_char;
}
#[test]
fn test_func() {
let results = c::func();
// how to print all string in results???
}
I've tried next idea without success:
let v: [str] = methods; // mismatched types: expected `[str]` but found
`**core::libc::types::os::arch::c95::c_char` (vector vs *-ptr)
What is the best way to do it?
Something like:
let buf = func();
let buflen = buf_len(buf);
let strs = unsafe {
let cstrs: [*c_char] = vec::unsafe::from_buf(buf, buflen);
vec::map(cstrs) {|cstr| str::unsafe::from_c_str(cstr) }
};
The problem is that `buf_len` doesn't exist. We could probably use some
iterators over unsafe pointers in core. Assuming that your array of
string pointers is null terminated, buf_len might look like:
unsafe fn buf_len(buf: **c_char) -> uint {
position(buf) {|i| i == ptr::null() }
}
// This should probably be in core::ptr
unsafe fn position<T>(buf: *T, f: (T) -> bool) -> uint {
let mut offset = 0u;
loop {
if f(*ptr::offset(ptr::addr_of(buf), offset) { ret offset; }
else { offset += 1u; }
}
}
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