Implement a function to humanize bytes. Remove dependency. (#12)

Cargo.toml

@@ -15,7 +15,6 @@ exclude = ["/.github/"]
 
 [dependencies]
 clap = { version = "4.5.16", features = ["derive"] }
-humanize-bytes = "1.0.6"
 spinoff = { version = "0.8.0", features = ["dots"] }
 
 [dev-dependencies]

src/bytes.rs

@@ -0,0 +1,44 @@
+#![allow(clippy::cast_precision_loss)]
+
+const UNITS: [&str; 6] = ["B", "KB", "MB", "GB", "TB", "PB"];
+
+const BASE: u64 = 1000;
+
+pub fn humanize(bytes: u64) -> String {
+    if bytes < BASE {
+        return format!("{bytes} B");
+    }
+    let exponent = bytes.ilog10() / BASE.ilog10();
+    let unit = UNITS[exponent as usize];
+    let value = bytes as f64 / BASE.pow(exponent) as f64;
+    let precision = match unit {
+        "KB" => 0,
+        "MB" => 1,
+        _ => 2,
+    };
+    format!("{value:.precision$} {unit}")
+}
+
+#[cfg(test)]
+mod test {
+    use super::humanize;
+
+    #[test]
+    fn test_humanize() {
+        assert_eq!(humanize(0), "0 B");
+        assert_eq!(humanize(256), "256 B");
+        assert_eq!(humanize(512), "512 B");
+        assert_eq!(humanize(1_000), "1 KB");
+        assert_eq!(humanize(2_650), "3 KB");
+        assert_eq!(humanize(737_525), "738 KB");
+        assert_eq!(humanize(1_000_000), "1.0 MB");
+        assert_eq!(humanize(1_240_000), "1.2 MB");
+        assert_eq!(humanize(1_250_000), "1.2 MB");
+        assert_eq!(humanize(1_260_000), "1.3 MB");
+        assert_eq!(humanize(10_525_000), "10.5 MB");
+        assert_eq!(humanize(2_886_000_000), "2.89 GB");
+        assert_eq!(humanize(200_500_150_001), "200.50 GB");
+        assert_eq!(humanize(50_000_000_000_000), "50.00 TB");
+        assert_eq!(humanize(1_421_000_000_000_000), "1.42 PB");
+    }
+}

src/files.rs

@@ -3,7 +3,7 @@ use std::fs::ReadDir;
 use std::io;
 use std::path::PathBuf;
 
-use humanize_bytes::humanize_bytes_decimal;
+use crate::bytes;
 
 pub fn from_path(path: &str) -> io::Result<FileIter> {
     let dir = std::fs::read_dir(path)?;
@@ -27,7 +27,7 @@ impl File {
 
 impl Display for File {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        write!(f, "{}: {}", self.size, self.path.display())
+        write!(f, "{} {}", self.size, self.path.display())
     }
 }
 
@@ -36,7 +36,7 @@ pub struct Size(u64);
 
 impl Display for Size {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        write!(f, "{:>8}", humanize_bytes_decimal!(self.0))
+        write!(f, "{}", bytes::humanize(self.0))
     }
 }
 
@@ -84,11 +84,11 @@ mod test {
         let cases = vec![
             Case {
                 file: File::new("/path/to/file.txt", 1000),
-                want: "    1 kB: /path/to/file.txt",
+                want: "1 KB /path/to/file.txt",
             },
             Case {
                 file: File::new("/path/to/file.txt", 34250),
-                want: " 34.2 kB: /path/to/file.txt",
+                want: "34 KB /path/to/file.txt",
             },
         ];
         for case in cases {

src/lib.rs

@@ -1,3 +1,4 @@
+mod bytes;
 mod files;
 
 use std::{collections::BTreeMap, io};

tests/cli.rs

@@ -43,10 +43,10 @@ fn binary_with_no_args_prints_top_5_largest_files_under_working_directory() {
 fn binary_with_path_arg_prints_the_top_5_largest_files_under_the_given_path() {
     let want = [
         "*** Top 5 largest files ***",
-        "     7 B: ./testdata/en/world.txt",
-        "     6 B: ./testdata/es/mundo.txt",
-        "     6 B: ./testdata/en/hello.txt",
-        "     5 B: ./testdata/es/hola.txt",
+        "7 B ./testdata/en/world.txt",
+        "6 B ./testdata/es/mundo.txt",
+        "6 B ./testdata/en/hello.txt",
+        "5 B ./testdata/es/hola.txt",
     ];
     Command::cargo_bin("dstats")
         .unwrap()