Initial commit

.gitignore

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+/target
+Cargo.lock

Cargo.toml

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+[package]
+name = "unified-diff"
+version = "0.1.0"
+authors = [
+    "Michael Howell <michael@notriddle.com>",
+    "The Rust Project Developers"
+]
+edition = "2018"
+
+[[bin]]
+name = "unified-diff"
+
+[dependencies]
+diff = "0.1.10"

README.md

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+A GNU unified diff generator. Oracle tested against GNU patch 2.7.6
+
+Based on the incomplete diff generator in https://github.com/rust-lang/rust/blob/master/src/tools/compiletest/src/runtest.rs,
+but it implements a different format.
+
+```
+~/unified-diff$ cargo run Cargo.lock Cargo.toml 
+    Finished dev [unoptimized + debuginfo] target(s) in 0.00s
+     Running `target/debug/unified-diff Cargo.lock Cargo.toml`
+--- Cargo.lock	
++++ Cargo.toml	
+@@ -1,14 +1,14 @@
+-# This file is automatically @generated by Cargo.
+-# It is not intended for manual editing.
+-[[package]]
+-name = "diff"
+-version = "0.1.12"
+-source = "registry+https://github.com/rust-lang/crates.io-index"
+-checksum = "0e25ea47919b1560c4e3b7fe0aaab9becf5b84a10325ddf7db0f0ba5e1026499"
+-
+-[[package]]
++[package]
+ name = "unified-diff"
+ version = "0.1.0"
+-dependencies = [
+- "diff",
++authors = [
++    "Michael Howell <michael@notriddle.com>",
++    "The Rust Project Developers"
+ ]
++edition = "2018"
++
++[[bin]]
++name = "unified-diff"
++
++[dependencies]
++diff = "0.1.10"
+```
+

src/main.rs

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+// Sample program. Do not use.
+use std::env;
+use std::fs;
+use std::io::{self, Write};
+use std::process;
+fn main() {
+    let mut o = env::args_os();
+    // parse CLI
+    let exe = match o.next() {
+        Some(from) => from,
+        None => {
+            eprintln!("Usage: [exe] [from] [to]");
+            process::exit(1);
+        }
+    };
+    let from = match o.next() {
+        Some(from) => from,
+        None => {
+            eprintln!("Usage: {} [from] [to]", exe.to_string_lossy());
+            process::exit(1);
+        }
+    };
+    let to = match o.next() {
+        Some(from) => from,
+        None => {
+            eprintln!("Usage: {} [from] [to]", exe.to_string_lossy());
+            process::exit(1);
+        }
+    };
+    // read files
+    let from_content = match fs::read(&from) {
+        Ok(from_content) => from_content,
+        Err(e) => {
+            eprintln!("Failed to read from-file: {}", e);
+            process::exit(2);
+        }
+    };
+    let to_content = match fs::read(&to) {
+        Ok(to_content) => to_content,
+        Err(e) => {
+            eprintln!("Failed to read to-file: {}", e);
+            process::exit(2);
+        }
+    };
+    // run diff
+    io::stdout()
+        .write_all(&unified_diff::diff(
+            &from_content,
+            &from.to_string_lossy(),
+            &to_content,
+            &to.to_string_lossy(),
+            3,
+        ))
+        .unwrap();
+}