diff options
Diffstat (limited to 'meap/meap-code/ch3/fileresult')
-rw-r--r-- | meap/meap-code/ch3/fileresult/Cargo.toml | 7 | ||||
-rw-r--r-- | meap/meap-code/ch3/fileresult/src/main.rs | 65 |
2 files changed, 72 insertions, 0 deletions
diff --git a/meap/meap-code/ch3/fileresult/Cargo.toml b/meap/meap-code/ch3/fileresult/Cargo.toml new file mode 100644 index 0000000..d5902d0 --- /dev/null +++ b/meap/meap-code/ch3/fileresult/Cargo.toml @@ -0,0 +1,7 @@ +[package] +name = "fileresult" +version = "0.1.0" +authors = ["Tim McNamara <code@timmcnamara.co.nz>"] + +[dependencies] +rand = "0.3"
\ No newline at end of file diff --git a/meap/meap-code/ch3/fileresult/src/main.rs b/meap/meap-code/ch3/fileresult/src/main.rs new file mode 100644 index 0000000..c02d959 --- /dev/null +++ b/meap/meap-code/ch3/fileresult/src/main.rs @@ -0,0 +1,65 @@ +extern crate rand; // <1> +use rand::Rng; // <2> + +fn one_in(n: u32) -> bool { // <3> + rand::thread_rng().gen_weighted_bool(n) +} + +#[derive(Debug)] +struct File { + name: String, + data: Vec<u8>, +} + +impl File { + fn new(name: &str) -> File { + File { name: String::from(name), data: Vec::new() } // <4> + } + + fn new_with_data(name: &str, data: &Vec<u8>) -> File { + let mut f = File::new(name); + f.data = data.clone(); + f + } + + fn read(self: &File, save_to: &mut Vec<u8>) -> Result<usize, String> { // <5> + let mut tmp = self.data.clone(); + let read_length = tmp.len(); + save_to.reserve(read_length); + save_to.append(&mut tmp); + Ok(read_length) // <6> + } +} + +fn open(f: File) -> Result<File, String> { + if one_in(10_000) { // <7> + let err_msg = String::from("Permission denied"); + return Err(err_msg); + } + Ok(f) +} + +fn close(f: File) -> Result<File, String> { + if one_in(100_000) { // <8> + let err_msg = String::from("Interrupted by signal!"); + return Err(err_msg); + } + Ok(f) +} + +fn main() { + let f4_data: Vec<u8> = vec![114, 117, 115, 116, 33]; + let mut f4 = File::new_with_data("4.txt", &f4_data); + + let mut buffer: Vec<u8> = vec![]; + + f4 = open(f4).unwrap(); // <9> + let f4_length = f4.read(&mut buffer).unwrap(); // <9> + f4 = close(f4).unwrap(); // <9> + + let text = String::from_utf8_lossy(&buffer); + + println!("{:?}", f4); + println!("{} is {} bytes long", &f4.name, f4_length); + println!("{}", text); +}
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