initial commit with base feature set

.gitignore

@@ -0,0 +1 @@
+/target

Cargo.lock

@@ -0,0 +1,87 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "argh"
+version = "0.1.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "91792f088f87cdc7a2cfb1d617fa5ea18d7f1dc22ef0e1b5f82f3157cdc522be"
+dependencies = [
+ "argh_derive",
+ "argh_shared",
+]
+
+[[package]]
+name = "argh_derive"
+version = "0.1.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c4eb0c0c120ad477412dc95a4ce31e38f2113e46bd13511253f79196ca68b067"
+dependencies = [
+ "argh_shared",
+ "heck",
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "argh_shared"
+version = "0.1.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "781f336cc9826dbaddb9754cb5db61e64cab4f69668bd19dcc4a0394a86f4cb1"
+
+[[package]]
+name = "chop"
+version = "0.1.0"
+dependencies = [
+ "argh",
+]
+
+[[package]]
+name = "heck"
+version = "0.3.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "87cbf45460356b7deeb5e3415b5563308c0a9b057c85e12b06ad551f98d0a6ac"
+dependencies = [
+ "unicode-segmentation",
+]
+
+[[package]]
+name = "proc-macro2"
+version = "1.0.24"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1e0704ee1a7e00d7bb417d0770ea303c1bccbabf0ef1667dae92b5967f5f8a71"
+dependencies = [
+ "unicode-xid",
+]
+
+[[package]]
+name = "quote"
+version = "1.0.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c3d0b9745dc2debf507c8422de05d7226cc1f0644216dfdfead988f9b1ab32a7"
+dependencies = [
+ "proc-macro2",
+]
+
+[[package]]
+name = "syn"
+version = "1.0.64"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3fd9d1e9976102a03c542daa2eff1b43f9d72306342f3f8b3ed5fb8908195d6f"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "unicode-xid",
+]
+
+[[package]]
+name = "unicode-segmentation"
+version = "1.7.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bb0d2e7be6ae3a5fa87eed5fb451aff96f2573d2694942e40543ae0bbe19c796"
+
+[[package]]
+name = "unicode-xid"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f7fe0bb3479651439c9112f72b6c505038574c9fbb575ed1bf3b797fa39dd564"

Cargo.toml

@@ -0,0 +1,10 @@
+[package]
+name = "chop"
+version = "0.1.0"
+authors = ["Mike Cugini <mike@betamike.com>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+argh = "0.1.4"

src/main.rs

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+use std::error::Error;
+use std::fs::File;
+use std::io::{self, BufReader};
+use std::io::prelude::*;
+
+use argh::FromArgs;
+
+#[derive(FromArgs)]
+#[argh(
+    description = "\
+    chop off bits of file\n\n\
+    chop will take produce --count files of --lines lines from the beginning of a\n\
+    file or stdin. Any remaining lines will be written to a final catchall file.")]
+struct Options {
+
+    /// number of lines in each chunk
+    #[argh(option, short = 'n')]
+    lines: usize,
+
+    /// count of chunks to produce (default 1)
+    #[argh(option, short = 'c', default = "1")]
+    count: usize,
+
+    /// optional prefix to use for generated files (default "")
+    #[argh(option, short = 'p', default = "String::from(\"\")")]
+    prefix: String,
+
+    /// use numeric suffixes starting with 0, not alphabetic 
+    #[argh(switch, short = 'd')]
+    numeric: bool,
+
+    /// use numeric suffixes starting with 0, not alphabetic 
+    #[argh(option, long = "numeric-start", default = "0")]
+    numeric_start: usize,
+
+    /// filename to read from, or "-" for stdin (default "-")
+    #[argh(positional, default = "String::from(\"-\")")]
+    filename: String,
+
+
+}
+
+struct AlphabeticSuffixGenerator {
+    suffix: Vec<u8>,
+    remaining: usize,
+}
+
+impl AlphabeticSuffixGenerator {
+    fn new(count: usize) -> AlphabeticSuffixGenerator {
+        // given 27 letters, minimum number of digits is floor( Log 27 (count) + 1 )
+        let suffix_length =  ((count as f64).log(27f64) + 1.0).floor() as usize;
+
+        let mut suffix = vec![b'a'; suffix_length];
+        suffix[suffix_length-1] -= 1;
+
+        AlphabeticSuffixGenerator{suffix, remaining: count}
+    }
+}
+
+impl Iterator for AlphabeticSuffixGenerator {
+    type Item = String;
+
+    fn next(&mut self) -> Option<String> {
+        if self.remaining == 0 {
+            return None
+        }
+        for idx in (0..self.suffix.len()).rev() {
+            if self.suffix[idx] < b'z' {
+                self.suffix[idx] += 1;
+                break
+            } else {
+                self.suffix[idx] = b'a';
+            }
+        }
+        self.remaining -= 1;
+        Some(String::from_utf8(self.suffix.to_vec()).expect("invalid suffix generated"))
+    }
+}
+
+
+fn try_main() -> Result<(), Box<dyn Error>> {
+    let opts: Options = argh::from_env();
+
+    let input: Box<dyn Read> = match opts.filename.as_str() {
+        "-" => Box::new(io::stdin()),
+         path => { 
+             match File::open(path) {
+                 Err(why) => panic!("failed to open {}: {}", path, why),
+                 Ok(file) => Box::new(file),
+            }
+         },
+    };
+
+    let prefix = match opts.prefix.as_str() {
+        "" => String::from(""),
+        _ => opts.prefix + "_",
+    };
+   
+    let suffix_gen: Box<dyn Iterator<Item = String>> = if opts.numeric {
+        Box::new((opts.numeric_start..(opts.numeric_start + opts.count)).map(|num| format!("{}", num)))
+    } else {
+        Box::new(AlphabeticSuffixGenerator::new(opts.count))
+    };
+
+    let mut eof = false;
+    let mut reader = BufReader::new(input);
+    for suffix in suffix_gen {
+        let mut out_file = File::create(format!("{}{}", prefix, suffix))?;
+        let mut line = String::new();
+        for _ in 0..opts.lines {
+            match reader.read_line(&mut line)? {
+                0 => {
+                    eof = true;
+                    break
+                },
+                _ => {
+                    out_file.write_all(line.as_bytes())?;
+                    line.clear();
+                }
+            };
+        }
+    }
+    // see if there's anything left for the remainder file
+    if !eof {
+        let mut out_file = File::create(format!("{}rest", prefix))?;
+        for result in reader.lines() {
+            // lines() strips newline characters, so add one
+            out_file.write_all((result?+"\n").as_bytes())?;
+        };
+    }
+    
+    Ok(())
+}
+
+fn main() {
+    // display nicer, non-debug representation of the error
+    if let Err(err) = try_main() {
+        eprintln!("{}", err);
+        std::process::exit(1);
+    }
+}