1 files changed, 116 insertions, 0 deletions
diff --git a/packages/svgbob/src/buffer/string_buffer.rs b/packages/svgbob/src/buffer/string_buffer.rs
new file mode 100644
index 0000000..9350a90
--- /dev/null
+++ b/packages/svgbob/src/buffer/string_buffer.rs
@@ -0,0 +1,116 @@
+use std::ops::{Deref, DerefMut};
+use unicode_width::UnicodeWidthChar;
+
+/// A 2D string buffer
+/// where you can insert a character to any cell on the 2D grid
+/// each cell can be assigned with a string
+/// taking into account utf8 code which can not be char
+/// including but not limited to multi-width chars
+pub struct StringBuffer(Vec<Vec<char>>);
+
+impl Deref for StringBuffer {
+    type Target = Vec<Vec<char>>;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+impl DerefMut for StringBuffer {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        &mut self.0
+    }
+}
+
+impl Default for StringBuffer {
+    fn default() -> Self {
+        Self(vec![])
+    }
+}
+
+impl StringBuffer {
+    pub fn new() -> Self {
+        StringBuffer(vec![])
+    }
+
+    /// add rows to this buffer
+    fn add_rows(&mut self, n: i32) {
+        for _i in 0..n {
+            self.push(vec![]);
+        }
+    }
+
+    /// add columns to the specified row of this buffer
+    fn add_column(&mut self, row: usize, n: i32) {
+        for _i in 0..n {
+            self[row].push(' ');
+        }
+    }
+
+    /// put a character in this x and y location, replacing the old character
+    /// if there is already
+    /// x and y can also be negative
+    pub fn add_char(&mut self, x: i32, y: i32, ch: char) {
+        if x >= 0 && y >= 0 {
+            if ch == '\0' {
+                println!("skipping {}", ch);
+            } else {
+                let row_index = y as usize;
+                let column_index = x as usize;
+                let row_diff = y - self.len() as i32;
+                if row_diff >= 0 {
+                    self.add_rows(row_diff + 1);
+                }
+                let column = &self[y as usize];
+                let column_diff = x - column.len() as i32;
+                if column_diff >= 0 {
+                    self.add_column(row_index as usize, column_diff + 1);
+                }
+                self[row_index][column_index] = ch;
+            }
+        }
+    }
+
+    /// replace insert a string on this location
+    pub fn add_str(&mut self, x: i32, y: i32, s: &str) {
+        for (i, ch) in s.chars().enumerate() {
+            self.add_char(x + i as i32, y, ch);
+        }
+    }
+}
+
+impl From<&str> for StringBuffer {
+    fn from(s: &str) -> Self {
+        let mut rows = vec![];
+        for line in s.lines() {
+            let mut row = vec![];
+            for ch in line.chars() {
+                row.push(ch);
+                if let Some(width) = ch.width() {
+                    for _i in 1..width {
+                        row.push('\0');
+                    }
+                }
+            }
+            rows.push(row);
+        }
+
+        StringBuffer(rows)
+    }
+}
+
+impl ToString for StringBuffer {
+    fn to_string(&self) -> String {
+        let mut lines = vec![];
+        for row in self.iter() {
+            let row_contents: Vec<String> = row
+                .iter()
+                .filter(|ch| **ch != '\0')
+                .map(ToString::to_string)
+                .collect();
+            let line = row_contents.join("").trim_end().to_string();
+            lines.push(line);
+        }
+        lines.join("\n")
+    }
+}