From: Tilman Sauerbeck <tilman@code-monkey.de>
Date: Sun, 5 Jan 2020 14:49:55 +0000 (+0100)
Subject: common: Add the yencode module.
X-Git-Url: http://git.code-monkey.de/?p=gps-watch.git;a=commitdiff_plain;h=0a39b1668c8437a34187fbb6166c7d56986cbb3d

common: Add the yencode module.
---

diff --git a/SConscript.libcommon b/SConscript.libcommon
index a7c5aff..3687908 100644
--- a/SConscript.libcommon
+++ b/SConscript.libcommon
@@ -25,6 +25,7 @@ source_files_rs = [
     'src/common/storage.rs',
     'src/common/mx25l.rs',
     'src/common/shell.rs',
+    'src/common/yencode.rs',
 ]
 
 source_files_c = [
diff --git a/src/common/lib.rs b/src/common/lib.rs
index dd33c68..384543e 100644
--- a/src/common/lib.rs
+++ b/src/common/lib.rs
@@ -47,3 +47,4 @@ pub mod time;
 pub mod storage;
 pub mod mx25l;
 pub mod shell;
+pub mod yencode;
diff --git a/src/common/yencode.rs b/src/common/yencode.rs
new file mode 100644
index 0000000..51ef756
--- /dev/null
+++ b/src/common/yencode.rs
@@ -0,0 +1,100 @@
+/*
+ * Copyright (c) 2017 Tilman Sauerbeck (tilman at code-monkey de)
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+use buffer::Buffer;
+use crc32::Crc32;
+use fmt::fmt_x32;
+
+pub struct Yencode<'a> {
+    buffer: &'a mut Buffer,
+    crc: Crc32,
+}
+
+impl<'a> Yencode<'a> {
+    pub fn new(buffer: &mut Buffer) -> Yencode {
+        Yencode {
+            buffer: buffer,
+            crc: Crc32::new(),
+        }
+    }
+
+    pub fn start(&mut self, filename: &[u8]) {
+        self.buffer.write(b"=ybegin name=");
+        self.buffer.write(filename);
+        self.buffer.write(b"\n");
+    }
+
+    fn encode_line(&mut self, input_buf: &[u8], output_buf: &mut [u8]) {
+        let mut output_buf_offset = 0;
+
+        for input in input_buf {
+            let mut c : u8 = *input;
+            c += 42;
+
+            match c {
+                b'\0' | b'\n' | b'\r' | b'=' => {
+                    output_buf[output_buf_offset] = b'=';
+                    output_buf_offset += 1;
+
+                    c += 64;
+                },
+                _ => {
+                }
+            }
+
+            output_buf[output_buf_offset] = c;
+            output_buf_offset += 1;
+        }
+
+        output_buf[output_buf_offset] = b'\n';
+        output_buf_offset += 1;
+
+        if output_buf[0] == b'.' {
+            self.buffer.write(b".");
+        }
+
+        self.buffer.write(&output_buf[0..output_buf_offset]);
+    }
+
+    pub fn data(&mut self, buf: &[u8]) {
+        self.crc.update(buf);
+
+        const INPUT_BYTES_PER_LINE : usize = 128;
+
+        for chunk in buf.chunks(INPUT_BYTES_PER_LINE) {
+            let mut linebuf = [0u8; INPUT_BYTES_PER_LINE << 1];
+
+            self.encode_line(chunk, &mut linebuf);
+        }
+    }
+
+    pub fn finish(&mut self) {
+        let mut yend = [b' '; 23];
+
+        yend[0..].copy_from_slice(b"=yend crc32=xxxxxxxx\n.\n");
+
+        fmt_x32(&mut yend[12..], self.crc.finish());
+
+        self.buffer.write(&yend);
+    }
+}