implement printing heatmap as hexdump

src/heatmap.rs

@@ -71,4 +71,93 @@ impl Heatmap {
     pub fn byte(&self, index: usize) -> u8 {
         self.data[index]
     }
+
+    pub fn print_as_hex(&self) -> std::io::Result<()> {
+        use crossterm::{
+            style::{Attribute, Color, Print, SetAttribute, SetBackgroundColor},
+            QueueableCommand,
+        };
+        use std::io::{stdout, Write};
+
+        fn set_color(
+            mut out: impl QueueableCommand,
+            heatmap: &Heatmap,
+            index: usize,
+            num_colors: u16,
+        ) -> std::io::Result<()> {
+            let cost = heatmap.cost(index);
+            if num_colors < 256 {
+                let colors = [
+                    Color::Red,
+                    Color::Yellow,
+                    Color::Green,
+                    Color::Cyan,
+                    Color::Blue,
+                    Color::DarkBlue,
+                    Color::Black,
+                ];
+                let color_index = (3. - cost.log2())
+                    .round()
+                    .max(0.)
+                    .min((colors.len() - 1) as f32) as usize;
+                out.queue(SetBackgroundColor(colors[color_index]))?;
+            } else {
+                let colors = [
+                    196, 166, 136, 106, 76, 46, 41, 36, 31, 26, 21, 20, 19, 18, 17, 16,
+                ];
+                let color_index = ((3. - cost.log2()) * 2.5)
+                    .round()
+                    .max(0.)
+                    .min((colors.len() - 1) as f32) as usize;
+                out.queue(SetBackgroundColor(Color::AnsiValue(colors[color_index])))?;
+            }
+            out.queue(SetAttribute(if heatmap.is_literal(index) {
+                Attribute::Underlined
+            } else {
+                Attribute::NoUnderline
+            }))?;
+            Ok(())
+        }
+
+        let num_colors = crossterm::style::available_color_count();
+
+        let term_width = crossterm::terminal::size()?.0.min(120) as usize;
+        let bytes_per_row = (term_width - 8) / 4;
+
+        for row_start in (0..self.data.len()).step_by(bytes_per_row) {
+            let row_range = row_start..self.data.len().min(row_start + bytes_per_row);
+            let mut stdout = stdout();
+
+            stdout.queue(Print(&format!("{:04x}  ", row_start)))?;
+
+            for i in row_range.clone() {
+                set_color(&mut stdout, self, i, num_colors)?;
+                stdout.queue(Print(&format!("{:02x} ", self.data[i])))?;
+            }
+
+            let num_spaces = 1 + (bytes_per_row - (row_range.end - row_range.start)) * 3;
+            let gap: String = std::iter::repeat(' ').take(num_spaces).collect();
+            stdout
+                .queue(SetAttribute(Attribute::Reset))?
+                .queue(Print(&gap))?;
+
+            for i in row_range.clone() {
+                set_color(&mut stdout, self, i, num_colors)?;
+                let byte = self.data[i];
+                if byte >= 32 && byte < 127 {
+                    stdout.queue(Print(format!("{}", byte as char)))?;
+                } else {
+                    stdout.queue(Print("."))?;
+                }
+            }
+
+            stdout
+                .queue(SetAttribute(Attribute::Reset))?
+                .queue(Print("\n"))?;
+
+            stdout.flush()?;
+        }
+
+        Ok(())
+    }
 }