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-rw-r--r--ofborg/tickborg/src/writetoline.rs356
1 files changed, 356 insertions, 0 deletions
diff --git a/ofborg/tickborg/src/writetoline.rs b/ofborg/tickborg/src/writetoline.rs
new file mode 100644
index 0000000000..848464242d
--- /dev/null
+++ b/ofborg/tickborg/src/writetoline.rs
@@ -0,0 +1,356 @@
+use std::fs::File;
+use std::io::{BufRead, BufReader, Seek, SeekFrom, Write};
+
+pub struct LineWriter {
+ file: File,
+ buffer: Vec<String>,
+ last_line: usize,
+}
+
+impl LineWriter {
+ pub fn new(mut rw: File) -> LineWriter {
+ let buf = LineWriter::load_buffer(&mut rw);
+ let len = buf.len();
+
+ LineWriter {
+ file: rw,
+ buffer: buf,
+ last_line: len,
+ }
+ }
+
+ fn load_buffer(file: &mut File) -> Vec<String> {
+ file.seek(SeekFrom::Start(0)).unwrap();
+
+ let reader = BufReader::new(file.try_clone().unwrap());
+ reader
+ .lines()
+ .map(|line| match line {
+ Ok(s) => s,
+ Err(err) => format!("UTF-8 Decode err: {err:?}"),
+ })
+ .collect()
+ }
+
+ pub fn write_to_line(&mut self, line: usize, data: &str) {
+ let original_len = self.buffer.len();
+ while self.buffer.len() <= line {
+ self.buffer.push("".to_owned());
+ }
+
+ self.buffer.remove(line);
+ self.buffer.insert(line, data.to_owned());
+
+ if self.last_line > line {
+ // println!("taking the rewrite option");
+ // We're inserting in to the middle of a file, so just
+ // write the entire buffer again
+ self.file.set_len(0).unwrap();
+ self.file.seek(SeekFrom::Start(0)).unwrap();
+ self.file
+ .write_all(self.buffer.join("\n").as_bytes())
+ .unwrap();
+ self.file.write_all(b"\n").unwrap();
+ } else {
+ // println!("taking the append option");
+ // println!("Writing {:?} to line {}", data, line);
+
+ let buffer_start = original_len;
+ let buffer_end = line + 1;
+ let to_write = self.buffer[buffer_start..buffer_end].join("\n");
+ // println!("Full buffer: {:?}", self.buffer);
+ // println!("buffer[{}..{}] = {:?}", buffer_start, buffer_end, to_write);
+ // Inclusive range syntax (ie: ...) is experimental, so
+ // to include the final newline in to the written buffer
+ // we have to use one more than the range we want for the
+ // end
+ // println!("selected buffer: {:?}", to_write);
+ self.file.write_all(to_write.as_bytes()).unwrap();
+ self.file.write_all(b"\n").unwrap();
+ }
+
+ self.last_line = line;
+ }
+
+ pub fn inner(self) -> File {
+ self.file
+ }
+}
+
+#[cfg(test)]
+mod tests {
+ use super::*;
+ use crate::test_scratch::TestScratch;
+ use std::fs::File;
+ use std::fs::OpenOptions;
+ use std::io::Read;
+ use std::path::Path;
+ use std::time::Instant;
+
+ fn testfile(path: &Path) -> File {
+ OpenOptions::new()
+ .read(true)
+ .write(true)
+ .truncate(true)
+ .create(true)
+ .open(path)
+ .expect("failed to open scratch file")
+ }
+
+ fn assert_file_content<T>(f: &mut T, value: &str)
+ where
+ T: Read + Seek,
+ {
+ let mut mystr: String = String::new();
+ f.seek(SeekFrom::Start(0)).unwrap();
+ f.read_to_string(&mut mystr).unwrap();
+ assert_eq!(mystr, value);
+ }
+
+ #[test]
+ fn test_writer_line_ordered() {
+ let p = TestScratch::new_file("writetoline-ordered");
+ let mut f = testfile(&p.path());
+
+ assert_file_content(&mut f, "");
+
+ let mut writer = LineWriter::new(f);
+ writer.write_to_line(0, "hello");
+ f = writer.inner();
+
+ assert_file_content(&mut f, "hello\n");
+
+ let mut writer = LineWriter::new(f);
+ writer.write_to_line(1, "world");
+ f = writer.inner();
+
+ assert_file_content(&mut f, "hello\nworld\n");
+
+ let mut writer = LineWriter::new(f);
+ writer.write_to_line(2, ":)");
+ f = writer.inner();
+
+ assert_file_content(&mut f, "hello\nworld\n:)\n");
+ }
+
+ #[test]
+ fn test_writer_line_unordered() {
+ let p = TestScratch::new_file("writetoline-unordered");
+ let mut f = testfile(&p.path());
+
+ assert_file_content(&mut f, "");
+
+ {
+ let mut writer = LineWriter::new(f);
+ writer.write_to_line(2, ":)");
+ f = writer.inner();
+ }
+
+ assert_file_content(&mut f, "\n\n:)\n");
+
+ {
+ let mut writer = LineWriter::new(f);
+ writer.write_to_line(1, "world");
+ f = writer.inner();
+ }
+
+ assert_file_content(&mut f, "\nworld\n:)\n");
+
+ {
+ let mut writer = LineWriter::new(f);
+ writer.write_to_line(0, "hello");
+ f = writer.inner();
+ }
+
+ assert_file_content(&mut f, "hello\nworld\n:)\n");
+ }
+
+ #[test]
+ fn test_writer_line_unordered_long() {
+ let p = TestScratch::new_file("writetoline-unordered-long");
+ let mut f = testfile(&p.path());
+
+ assert_file_content(&mut f, "");
+
+ {
+ let mut writer = LineWriter::new(f);
+ writer.write_to_line(
+ 2,
+ "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA",
+ );
+ f = writer.inner();
+ }
+ assert_file_content(
+ &mut f,
+ "\n\nAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA\n",
+ );
+
+ {
+ let mut writer = LineWriter::new(f);
+ writer.write_to_line(
+ 1,
+ "BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB",
+ );
+ f = writer.inner();
+ }
+ assert_file_content(
+ &mut f,
+ "\nBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB\nAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA\n",
+ );
+
+ {
+ let mut writer = LineWriter::new(f);
+ writer.write_to_line(
+ 0,
+ "CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC",
+ );
+ f = writer.inner();
+ }
+ assert_file_content(
+ &mut f,
+ "CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC\nBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB\nAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA\n",
+ );
+ }
+
+ #[test]
+ fn test_writer_line_unordered_longish() {
+ let p = TestScratch::new_file("writetoline-unordered-longish");
+ let mut f = testfile(&p.path());
+
+ assert_file_content(&mut f, "");
+
+ {
+ let mut writer = LineWriter::new(f);
+ writer.write_to_line(2, "hello");
+ f = writer.inner();
+ }
+ assert_file_content(&mut f, "\n\nhello\n");
+
+ {
+ let mut writer = LineWriter::new(f);
+ writer.write_to_line(1, "mynameis");
+ f = writer.inner();
+ }
+ assert_file_content(&mut f, "\nmynameis\nhello\n");
+
+ {
+ let mut writer = LineWriter::new(f);
+ writer.write_to_line(0, "graham");
+ f = writer.inner();
+ }
+ assert_file_content(&mut f, "graham\nmynameis\nhello\n");
+ }
+
+ #[test]
+ fn test_writer_line_ordered_result() {
+ let p = TestScratch::new_file("writetoline-ordered-result");
+ let mut f = testfile(&p.path());
+
+ let mut writer = LineWriter::new(f);
+ writer.write_to_line(0, "hello");
+ writer.write_to_line(1, "world");
+ writer.write_to_line(2, ":)");
+ f = writer.inner();
+
+ assert_file_content(&mut f, "hello\nworld\n:)\n");
+ }
+
+ #[test]
+ fn test_writer_line_unordered_result() {
+ let p = TestScratch::new_file("writetoline-unordered-result");
+ let mut f = testfile(&p.path());
+
+ let mut writer = LineWriter::new(f);
+ writer.write_to_line(2, ":)");
+ writer.write_to_line(1, "world");
+ writer.write_to_line(0, "hello");
+ f = writer.inner();
+
+ assert_file_content(&mut f, "hello\nworld\n:)\n");
+ }
+
+ #[test]
+ fn test_writer_line_unordered_long_result() {
+ let p = TestScratch::new_file("writetoline-unordered-long-result");
+ let mut f = testfile(&p.path());
+
+ let mut writer = LineWriter::new(f);
+ writer.write_to_line(
+ 2,
+ "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA",
+ );
+ writer.write_to_line(
+ 1,
+ "BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB",
+ );
+ writer.write_to_line(
+ 0,
+ "CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC",
+ );
+ f = writer.inner();
+
+ assert_file_content(
+ &mut f,
+ "CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC\nBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB\nAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA\n",
+ );
+ }
+
+ #[test]
+ fn test_writer_line_unordered_longish_result() {
+ let p = TestScratch::new_file("writetoline-unordered-longish-result");
+ let mut f = testfile(&p.path());
+
+ let mut writer = LineWriter::new(f);
+ writer.write_to_line(2, "hello");
+ writer.write_to_line(1, "mynameis");
+ writer.write_to_line(0, "graham");
+ f = writer.inner();
+
+ assert_file_content(&mut f, "graham\nmynameis\nhello\n");
+ }
+
+ #[test]
+ fn test_writer_line_middle() {
+ let p = TestScratch::new_file("writetoline-middle");
+ let mut f = testfile(&p.path());
+
+ assert_file_content(&mut f, "");
+
+ {
+ let mut writer = LineWriter::new(f);
+ writer.write_to_line(5, "hello");
+ f = writer.inner();
+ }
+ assert_file_content(&mut f, "\n\n\n\n\nhello\n");
+ }
+
+ #[test]
+ fn bench_lots_of_ordered_lines() {
+ let p = TestScratch::new_file("bench-ordered-lines");
+ let f = testfile(&p.path());
+ let mut writer = LineWriter::new(f);
+
+ let timer = Instant::now();
+
+ for i in 0..3000 {
+ writer.write_to_line(i, "This is my line!");
+ }
+
+ println!("ordered took: {:?}", timer.elapsed());
+ }
+
+ #[test]
+ fn bench_lots_of_reversed_lines() {
+ let p = TestScratch::new_file("bench-reversed-lines");
+ let f = testfile(&p.path());
+ let mut writer = LineWriter::new(f);
+
+ let timer = Instant::now();
+
+ for i in (0..3000).rev() {
+ writer.write_to_line(i, "This is my line!");
+ }
+
+ println!("reversed took: {:?}", timer.elapsed());
+ }
+}
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