From 0bc4834ae318502ac3575c0f7d073bbd3aedfe98 Mon Sep 17 00:00:00 2001
From: Jesse Luehrs <doy@tozt.net>
Date: Mon, 11 May 2020 18:52:14 -0400
Subject: add contents_between, for things like clipboard selections

---
 src/screen.rs            | 59 ++++++++++++++++++++++++++++++++++++++++++++++++
 tests/window_contents.rs | 34 ++++++++++++++++++++++++++++
 2 files changed, 93 insertions(+)

diff --git a/src/screen.rs b/src/screen.rs
index c50d077..a47bfa1 100644
--- a/src/screen.rs
+++ b/src/screen.rs
@@ -172,6 +172,65 @@ impl Screen {
         })
     }
 
+    /// Returns the text contents of the terminal logically between two cells.
+    /// This will include the remainder of the starting row after `start_col`,
+    /// followed by the entire contents of the rows between `start_row` and
+    /// `end_row`, followed by the beginning of the `end_row` up until
+    /// `end_col`. This is useful for things like determining the contents of
+    /// a clipboard selection.
+    #[must_use]
+    pub fn contents_between(
+        &self,
+        start_row: u16,
+        start_col: u16,
+        end_row: u16,
+        end_col: u16,
+    ) -> String {
+        match start_row.cmp(&end_row) {
+            std::cmp::Ordering::Less => {
+                let (_, cols) = self.size();
+                let mut contents = String::new();
+                for (i, row) in self
+                    .grid()
+                    .visible_rows()
+                    .enumerate()
+                    .skip(start_row as usize)
+                    .take(end_row as usize - start_row as usize + 1)
+                {
+                    if i == start_row as usize {
+                        row.write_contents(
+                            &mut contents,
+                            start_col,
+                            cols - start_col,
+                            false,
+                        );
+                        if !row.wrapped() {
+                            contents.push('\n');
+                        }
+                    } else if i == end_row as usize {
+                        row.write_contents(&mut contents, 0, end_col, false);
+                    } else {
+                        row.write_contents(&mut contents, 0, cols, false);
+                        if !row.wrapped() {
+                            contents.push('\n');
+                        }
+                    }
+                }
+                contents
+            }
+            std::cmp::Ordering::Equal => {
+                if start_col < end_col {
+                    self.rows(start_col, end_col - start_col)
+                        .nth(start_row as usize)
+                        .unwrap_or_else(String::new)
+                } else {
+                    String::new()
+                }
+            }
+            std::cmp::Ordering::Greater => String::new(),
+        }
+    }
+
     /// Returns the formatted visible contents of the terminal.
     ///
     /// Formatting information will be included inline as terminal escape
diff --git a/tests/window_contents.rs b/tests/window_contents.rs
index 39c8ad7..a300438 100644
--- a/tests/window_contents.rs
+++ b/tests/window_contents.rs
@@ -452,6 +452,40 @@ fn rows() {
     );
 }
 
+#[test]
+fn contents_between() {
+    let mut parser = vt100::Parser::default();
+    assert_eq!(parser.screen().contents_between(0, 0, 0, 0), "");
+    assert_eq!(parser.screen().contents_between(0, 0, 5, 0), "\n\n\n\n\n");
+    assert_eq!(parser.screen().contents_between(5, 0, 0, 0), "");
+
+    parser.process(
+        b"Lorem ipsum dolor sit amet, consectetur adipiscing elit, \
+        sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.\n\n\
+        Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris \
+        nisi ut aliquip ex ea commodo consequat.\n\n\
+        Duis aute irure dolor in reprehenderit in voluptate velit esse cillum \
+        dolore eu fugiat nulla pariatur.\n\n\
+        Excepteur sint occaecat cupidatat non proident, sunt in culpa qui \
+        officia deserunt mollit anim id est laborum.",
+    );
+    assert_eq!(parser.screen().contents_between(0, 0, 0, 0), "");
+    assert_eq!(
+        parser.screen().contents_between(0, 0, 0, 26),
+        "Lorem ipsum dolor sit amet"
+    );
+    assert_eq!(parser.screen().contents_between(0, 26, 0, 0), "");
+    assert_eq!(
+        parser.screen().contents_between(0, 57, 1, 43),
+        "sed do eiusmod tempor incididunt ut labore et dolore magna aliqua."
+    );
+    assert_eq!(
+        parser.screen().contents_between(0, 57, 2, 0),
+        "sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.\n"
+    );
+    assert_eq!(parser.screen().contents_between(2, 0, 0, 57), "");
+}
+
 #[test]
 fn diff_basic() {
     let mut parser = vt100::Parser::default();
-- 
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