diff options
| author | John Hodge (bugs) <tpg@mutabah.net> | 2014-11-22 23:36:20 +0800 |
|---|---|---|
| committer | John Hodge (bugs) <tpg@mutabah.net> | 2014-11-22 23:36:20 +0800 |
| commit | 7ad1a8b4b40784e0a10bd453c75dd0dcf123d5f1 (patch) | |
| tree | 0172ed546bdb00e86297d8d36d7cb0a0a1d111f3 /samples | |
| download | mrust-7ad1a8b4b40784e0a10bd453c75dd0dcf123d5f1.tar.gz | |
Initial commit, lexer structurally complete, parsing hacking up
Diffstat (limited to 'samples')
| -rw-r--r-- | samples/1.rs | 125 |
1 files changed, 125 insertions, 0 deletions
diff --git a/samples/1.rs b/samples/1.rs new file mode 100644 index 00000000..ce53ba54 --- /dev/null +++ b/samples/1.rs @@ -0,0 +1,125 @@ +// UTF8Reader
+// - by John Hodge (thePowersGang)
+//
+//
+// Reads a stream of UTF-8 encoded codepoints from a "Reader"
+use std::io::IoResult;
+
+/// Unicode replacement character
+static BADCHAR: char = '\uFFFD';
+
+/// UTF8 reader structure
+pub struct UTF8Reader<T: Reader>
+{
+ stream: T,
+}
+
+fn tochar(codepoint: u32) -> char
+{
+ match ::std::char::from_u32(codepoint)
+ {
+ Some(c) => c,
+ None => BADCHAR,
+ }
+}
+
+impl<T:Reader> UTF8Reader<T>
+{
+ pub fn new(reader: T) -> UTF8Reader<T>
+ {
+ UTF8Reader {
+ stream: reader,
+ }
+ }
+
+ /// Read a single codepoint from the stream.
+ /// On an encoding error, it returns '\uFFFD' (the unicode replacement character)
+ pub fn getc(&mut self) -> IoResult<char>
+ {
+ let ch1 = try!(self.stream.read_byte()) as u32;
+ if ch1 & 0xC0 == 0x80 {
+ return Ok( BADCHAR )
+ }
+ if ch1 & 0x80 == 0x00
+ {
+ // Single-byte
+ Ok( tochar(ch1) )
+ }
+ else if ch1 & 0xE0 == 0xC0
+ {
+ // Two-byte sequence
+ let ch2 = try!(self.stream.read_byte()) as u32;
+ if ch2 & 0xC0 != 0x80 {
+ return Ok( BADCHAR );
+ }
+
+ let ret = (ch1 & 0x1F << 6) | (ch2 & 0x3F << 0);
+ Ok( tochar(ret) )
+ }
+ else if ch1 & 0xF0 == 0xE0
+ {
+ // Three-byte sequence
+ let ch2 = try!(self.stream.read_byte()) as u32;
+ if ch2 & 0xC0 != 0x80 {
+ return Ok( BADCHAR );
+ }
+ let ch3 = try!(self.stream.read_byte()) as u32;
+ if ch3 & 0xC0 != 0x80 {
+ return Ok( BADCHAR );
+ }
+
+ let ret = (ch1 & 0x0F << 12) | (ch2 & 0x3F << 6) | (ch3 & 0x3F << 0);
+ Ok( tochar(ret) )
+ }
+ else if ch1 & 0xF8 == 0xF0
+ {
+ // Four-byte sequence
+ let ch2 = try!(self.stream.read_byte()) as u32;
+ if ch2 & 0xC0 != 0x80 {
+ return Ok( BADCHAR );
+ }
+ let ch3 = try!(self.stream.read_byte()) as u32;
+ if ch3 & 0xC0 != 0x80 {
+ return Ok( BADCHAR );
+ }
+ let ch4 = try!(self.stream.read_byte()) as u32;
+ if ch4 & 0xC0 != 0x80 {
+ return Ok( BADCHAR );
+ }
+
+ let ret = (ch1 & 0x07 << 18) | (ch2 & 0x3F << 12) | (ch3 & 0x3F << 6) | (ch4 & 0x3F << 0);
+ Ok( tochar(ret) )
+ }
+ else
+ {
+ // More than four bytes is invalid
+ Ok( BADCHAR )
+ }
+ }
+}
+
+/// Implmentation of the same interface as 'Chars' provides, returns None at the end of the stream
+impl<T:Reader> Iterator<IoResult<char>> for UTF8Reader<T>
+{
+ fn next(&mut self) -> Option<IoResult<char>>
+ {
+ // Get result from decoder
+ match self.getc()
+ {
+ // - All good, return a character
+ Ok(c) => Some( Ok(c) ),
+ // - Error, check if it's EOF
+ Err(e) => match e.kind {
+ // Return 'None' on EOF (end of stream)
+ ::std::io::EndOfFile => None,
+ _ => Some( Err( e ) ),
+ }
+ }
+ }
+}
+
+#[test]
+fn it_works() {
+}
+
+// vim: ft=rust
|