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author | Adam Carpenter <53hornet@gmail.com> | 2019-03-27 15:32:37 -0400 |
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committer | Adam Carpenter <53hornet@gmail.com> | 2019-03-27 15:32:37 -0400 |
commit | 67cdcc2e12118becb823e20a40cc2687f2b8425a (patch) | |
tree | ed92c3234b89079e6d4cf36f5e80c5ffa79def48 /meap/meap-code/ch3/fileresult/src/main.rs | |
parent | e25482fca375d318a39c3b54db396b0db6e0b263 (diff) | |
download | learning-rust-67cdcc2e12118becb823e20a40cc2687f2b8425a.tar.xz learning-rust-67cdcc2e12118becb823e20a40cc2687f2b8425a.zip |
Started Rust in Action MEAP.
Diffstat (limited to 'meap/meap-code/ch3/fileresult/src/main.rs')
-rw-r--r-- | meap/meap-code/ch3/fileresult/src/main.rs | 65 |
1 files changed, 65 insertions, 0 deletions
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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