1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134

//! Functions to find the difference between to texts (strings).
//! Usage
//! ----------
//!
//! Add the following to your Cargo.toml:
//!
//! ```toml
//! [dependencies.text_diff]
//!
//! git = "https://github.com/johannhof/text-diff.rs.git"
//! ```
//!
//! Now you can use the crate in your code
//!
//! ```ignore
//! extern crate text_diff;
//! ```

#![crate_name = "text_diff"]
#![doc(html_root_url = "https://johannhof.github.io/text-diff.rs/")]

// I can basically feel the karma already
#![deny(missing_docs)]

mod lcs;
mod merge;

use lcs::lcs;
use merge::merge;

/// Defines the contents of a changeset
/// Changesets will be delivered in order of appearance in the original string
/// Sequences of the same kind will be grouped into one Difference
#[derive(PartialEq, Debug)]
pub enum Difference {
    /// Sequences that are the same
    Same(String),
    /// Sequences that are an addition (don't appear in the first string)
    Add(String),
    /// Sequences that are a removal (don't appear in the second string)
    Rem(String)
}

/// Calculates the edit distance and the changeset for two given strings.
/// The first string is assumed to be the "original", the second to be an
/// edited version of the first. The third parameter specifies how to split
/// the input strings, leading to a more or less exact comparison.
///
/// Common splits are `""` for char-level, `" "` for word-level and `"\n"` for line-level.
///
/// Outputs the edit distance (how much the two strings differ) and a "changeset", that is
/// a `Vec` containing `Difference`s.
///
/// # Examples
///
/// ```
/// use text_diff::diff;
/// use text_diff::Difference;
///
/// let (dist, changeset) = diff("test", "tent", "");
///
/// assert_eq!(changeset, vec![
///     Difference::Same("te".to_string()),
///     Difference::Rem("s".to_string()),
///     Difference::Add("n".to_string()),
///     Difference::Same("t".to_string())
/// ]);
/// ```
pub fn diff(orig: &str, edit: &str, split: &str) -> (i32, Vec<Difference>) {
    let (dist, common) = lcs(orig, edit, split);
    (dist, merge(orig, edit, &common, split))
}

/// Prints a colorful visual representation of the diff.
/// This is just a convenience function for those who want quick results.
///
/// I recommend checking out the examples on how to build your
/// own diff output.
/// # Examples
///
/// ```
/// use text_diff::print_diff;
/// print_diff("Diffs are awesome", "Diffs are cool", " ");
/// ```
pub fn print_diff(orig: &str, edit: &str, split: &str) {
    let (_, changeset) = diff(orig, edit, split);
    let mut ret = String::new();

    for seq in changeset {
        match seq {
            Difference::Same(ref x) => {
                ret.push_str(x);
                ret.push_str(split);
            },
            Difference::Add(ref x) => {
                ret.push_str("\x1B[92m");
                ret.push_str(x);
                ret.push_str("\x1B[0m");
                ret.push_str(split);
            },
            Difference::Rem(ref x) => {
                ret.push_str("\x1B[91m");
                ret.push_str(x);
                ret.push_str("\x1B[0m");
                ret.push_str(split);
            }
        }
    }
    println!("{}", ret);
}

#[test]
fn test_diff() {
    let text1 = "Roses are red, violets are blue,\n\
                 I wrote this library,\n\
                 just for you.\n\
                 (It's true).";

    let text2 = "Roses are red, violets are blue,\n\
                 I wrote this documentation,\n\
                 just for you.\n\
                 (It's quite true).";

    let (dist, changeset) = diff(text1, text2, "\n");

    assert_eq!(changeset, vec![
         Difference::Same("Roses are red, violets are blue,".to_string()),
         Difference::Rem("I wrote this library,".to_string()),
         Difference::Add("I wrote this documentation,".to_string()),
         Difference::Same("just for you.".to_string()),
         Difference::Rem("(It's true).".to_string()),
         Difference::Add("(It's quite true).".to_string())
    ]);
}