repo: move all source code in crates directory

The top-level listing was just getting a bit too long for my taste. So
put all of the code in one directory and shrink the large top-level mess
to a small top-level mess.

NOTE: This commit only contains renames. The subsequent commit will
actually make ripgrep build again. We do it this way with the naive hope
that this will make it easier for git history to track the renames.
Sigh.

crates/cli/src/human.rs

@@ -0,0 +1,165 @@
+use std::error;
+use std::fmt;
+use std::io;
+use std::num::ParseIntError;
+
+use regex::Regex;
+
+/// An error that occurs when parsing a human readable size description.
+///
+/// This error provides a end user friendly message describing why the
+/// description coudln't be parsed and what the expected format is.
+#[derive(Clone, Debug, Eq, PartialEq)]
+pub struct ParseSizeError {
+    original: String,
+    kind: ParseSizeErrorKind,
+}
+
+#[derive(Clone, Debug, Eq, PartialEq)]
+enum ParseSizeErrorKind {
+    InvalidFormat,
+    InvalidInt(ParseIntError),
+    Overflow,
+}
+
+impl ParseSizeError {
+    fn format(original: &str) -> ParseSizeError {
+        ParseSizeError {
+            original: original.to_string(),
+            kind: ParseSizeErrorKind::InvalidFormat,
+        }
+    }
+
+    fn int(original: &str, err: ParseIntError) -> ParseSizeError {
+        ParseSizeError {
+            original: original.to_string(),
+            kind: ParseSizeErrorKind::InvalidInt(err),
+        }
+    }
+
+    fn overflow(original: &str) -> ParseSizeError {
+        ParseSizeError {
+            original: original.to_string(),
+            kind: ParseSizeErrorKind::Overflow,
+        }
+    }
+}
+
+impl error::Error for ParseSizeError {
+    fn description(&self) -> &str {
+        "invalid size"
+    }
+}
+
+impl fmt::Display for ParseSizeError {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        use self::ParseSizeErrorKind::*;
+
+        match self.kind {
+            InvalidFormat => write!(
+                f,
+                "invalid format for size '{}', which should be a sequence \
+                     of digits followed by an optional 'K', 'M' or 'G' \
+                     suffix",
+                self.original
+            ),
+            InvalidInt(ref err) => write!(
+                f,
+                "invalid integer found in size '{}': {}",
+                self.original, err
+            ),
+            Overflow => write!(f, "size too big in '{}'", self.original),
+        }
+    }
+}
+
+impl From<ParseSizeError> for io::Error {
+    fn from(size_err: ParseSizeError) -> io::Error {
+        io::Error::new(io::ErrorKind::Other, size_err)
+    }
+}
+
+/// Parse a human readable size like `2M` into a corresponding number of bytes.
+///
+/// Supported size suffixes are `K` (for kilobyte), `M` (for megabyte) and `G`
+/// (for gigabyte). If a size suffix is missing, then the size is interpreted
+/// as bytes. If the size is too big to fit into a `u64`, then this returns an
+/// error.
+///
+/// Additional suffixes may be added over time.
+pub fn parse_human_readable_size(size: &str) -> Result<u64, ParseSizeError> {
+    lazy_static! {
+        // Normally I'd just parse something this simple by hand to avoid the
+        // regex dep, but we bring regex in any way for glob matching, so might
+        // as well use it.
+        static ref RE: Regex = Regex::new(r"^([0-9]+)([KMG])?$").unwrap();
+    }
+
+    let caps = match RE.captures(size) {
+        Some(caps) => caps,
+        None => return Err(ParseSizeError::format(size)),
+    };
+    let value: u64 =
+        caps[1].parse().map_err(|err| ParseSizeError::int(size, err))?;
+    let suffix = match caps.get(2) {
+        None => return Ok(value),
+        Some(cap) => cap.as_str(),
+    };
+    let bytes = match suffix {
+        "K" => value.checked_mul(1 << 10),
+        "M" => value.checked_mul(1 << 20),
+        "G" => value.checked_mul(1 << 30),
+        // Because if the regex matches this group, it must be [KMG].
+        _ => unreachable!(),
+    };
+    bytes.ok_or_else(|| ParseSizeError::overflow(size))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn suffix_none() {
+        let x = parse_human_readable_size("123").unwrap();
+        assert_eq!(123, x);
+    }
+
+    #[test]
+    fn suffix_k() {
+        let x = parse_human_readable_size("123K").unwrap();
+        assert_eq!(123 * (1 << 10), x);
+    }
+
+    #[test]
+    fn suffix_m() {
+        let x = parse_human_readable_size("123M").unwrap();
+        assert_eq!(123 * (1 << 20), x);
+    }
+
+    #[test]
+    fn suffix_g() {
+        let x = parse_human_readable_size("123G").unwrap();
+        assert_eq!(123 * (1 << 30), x);
+    }
+
+    #[test]
+    fn invalid_empty() {
+        assert!(parse_human_readable_size("").is_err());
+    }
+
+    #[test]
+    fn invalid_non_digit() {
+        assert!(parse_human_readable_size("a").is_err());
+    }
+
+    #[test]
+    fn invalid_overflow() {
+        assert!(parse_human_readable_size("9999999999999999G").is_err());
+    }
+
+    #[test]
+    fn invalid_suffix() {
+        assert!(parse_human_readable_size("123T").is_err());
+    }
+}