Add bufio.Writer and bufio.Read_Writer

2 files changed, 323 insertions, 0 deletions

diff --git a/core/bufio/read_writer.odin b/core/bufio/read_writer.odin
new file mode 100644
index 000000000..f60e17d2d
--- /dev/null
+++ b/core/bufio/read_writer.odin
@@ -0,0 +1,68 @@
+package bufio
+
+import "core:io"
+
+// Read_Writer stores pointers to a Reader and a Writer
+Read_Writer :: struct {
+	r: ^Reader,
+	w: ^Writer,
+}
+
+
+read_writer_init :: proc(rw: ^Read_Writer, r: ^Reader, w: ^Writer) {
+	rw.r, rw.w = r, w;
+}
+
+read_writer_to_stream :: proc(rw: ^Read_Writer) -> (s: io.Stream) {
+	s.stream_data = rw;
+	s.stream_vtable = _read_writer_vtable;
+	return;
+}
+
+@(private)
+_read_writer_vtable := &io.Stream_VTable{
+	impl_read = proc(s: io.Stream, p: []byte) -> (n: int, err: io.Error) {
+		b := (^Read_Writer)(s.stream_data).r;
+		return reader_read(b, p);
+	},
+	impl_read_byte = proc(s: io.Stream) -> (c: byte, err: io.Error) {
+		b := (^Read_Writer)(s.stream_data).r;
+		return reader_read_byte(b);
+	},
+	impl_unread_byte = proc(s: io.Stream) -> io.Error {
+		b := (^Read_Writer)(s.stream_data).r;
+		return reader_unread_byte(b);
+	},
+	impl_read_rune = proc(s: io.Stream) -> (r: rune, size: int, err: io.Error) {
+		b := (^Read_Writer)(s.stream_data).r;
+		return reader_read_rune(b);
+	},
+	impl_unread_rune = proc(s: io.Stream) -> io.Error {
+		b := (^Read_Writer)(s.stream_data).r;
+		return reader_unread_rune(b);
+	},
+	impl_write_to = proc(s: io.Stream, w: io.Writer) -> (n: i64, err: io.Error) {
+		b := (^Read_Writer)(s.stream_data).r;
+		return reader_write_to(b, w);
+	},
+	impl_flush = proc(s: io.Stream)  -> io.Error {
+		b := (^Read_Writer)(s.stream_data).w;
+		return writer_flush(b);
+	},
+	impl_write = proc(s: io.Stream, p: []byte) -> (n: int, err: io.Error) {
+		b := (^Read_Writer)(s.stream_data).w;
+		return writer_write(b, p);
+	},
+	impl_write_byte = proc(s: io.Stream, c: byte) -> io.Error {
+		b := (^Read_Writer)(s.stream_data).w;
+		return writer_write_byte(b, c);
+	},
+	impl_write_rune = proc(s: io.Stream, r: rune) -> (int, io.Error) {
+		b := (^Read_Writer)(s.stream_data).w;
+		return writer_write_rune(b, r);
+	},
+	impl_read_from = proc(s: io.Stream, r: io.Reader) -> (n: i64, err: io.Error) {
+		b := (^Read_Writer)(s.stream_data).w;
+		return writer_read_from(b, r);
+	},
+};
diff --git a/core/bufio/writer.odin b/core/bufio/writer.odin
new file mode 100644
index 000000000..97f24a224
--- /dev/null
+++ b/core/bufio/writer.odin
@@ -0,0 +1,255 @@
+package bufio
+
+import "core:io"
+import "core:mem"
+import "core:unicode/utf8"
+// import "core:bytes"
+
+// Writer is a buffered wrapper for an io.Writer
+Writer :: struct {
+	buf:            []byte,
+	buf_allocator:  mem.Allocator,
+
+	wr: io.Writer,
+	n: int,
+
+	err: io.Error,
+
+}
+
+writer_init :: proc(b: ^Writer, wr: io.Writer, size: int = DEFAULT_BUF_SIZE, allocator := context.allocator) {
+	size := size;
+	size = max(size, MIN_READ_BUFFER_SIZE);
+	writer_reset(b, wr);
+	b.buf_allocator = allocator;
+	b.buf = make([]byte, size, allocator);
+}
+
+writer_init_with_buf :: proc(b: ^Writer, wr: io.Writer, buf: []byte) {
+	writer_reset(b, wr);
+	b.buf_allocator = {};
+	b.buf = buf;
+}
+
+// writer_destroy destroys the underlying buffer with its associated allocator IFF that allocator has been set
+writer_destroy :: proc(b: ^Writer) {
+	delete(b.buf, b.buf_allocator);
+	b^ = {};
+}
+
+// writer_size returns the size of underlying buffer in bytes
+writer_size :: proc(b: ^Writer) -> int {
+	return len(b.buf);
+}
+
+writer_reset :: proc(b: ^Writer, w: io.Writer) {
+	b.wr = w;
+	b.n = 0;
+	b.err = nil;
+}
+
+
+// writer_flush writes any buffered data into the underlying io.Writer
+writer_flush :: proc(b: ^Writer) -> io.Error {
+	if b.err != nil {
+		return b.err;
+	}
+	if b.n == 0 {
+		return nil;
+	}
+
+	n, err := io.write(b.wr, b.buf[0:b.n]);
+	if n < b.n && err == nil {
+		err = .Short_Write;
+	}
+	if err != nil {
+		if n > 0 && n < b.n {
+			copy(b.buf[:b.n-n], b.buf[n : b.n]);
+		}
+		b.n -= n;
+		b.err = err;
+		return err;
+	}
+	b.n = 0;
+	return nil;
+}
+
+// writer_available returns how many bytes are unused in the buffer
+writer_available :: proc(b: ^Writer) -> int {
+	return len(b.buf) - b.n;
+}
+
+// writer_buffered returns the number of bytes that have been writted into the current buffer
+writer_buffered :: proc(b: ^Writer) -> int {
+	return b.n;
+}
+
+// writer_write writes the contents of p into the buffer
+// It returns the number of bytes written
+// If n < len(p), it will return an error explaining why the write is short
+writer_write :: proc(b: ^Writer, p: []byte) -> (n: int, err: io.Error) {
+	p := p;
+	for len(p) > writer_available(b) && b.err == nil {
+		m: int;
+		if writer_buffered(b) == 0 {
+			m, b.err = io.write(b.wr, p);
+		} else {
+			m = copy(b.buf[b.n:], p);
+			b.n += m;
+			writer_flush(b);
+		}
+		n += m;
+		p = p[m:];
+	}
+	if b.err != nil {
+		return n, b.err;
+	}
+	m := copy(b.buf[b.n:], p);
+	b.n += m;
+	m += n;
+	return m, nil;
+}
+
+// writer_write_byte writes a single byte
+writer_write_byte :: proc(b: ^Writer, c: byte) -> io.Error {
+	if b.err != nil {
+		return b.err;
+	}
+	if writer_available(b) <= 0 && writer_flush(b) != nil {
+		return b.err;
+	}
+	b.buf[b.n] = c;
+	b.n += 1;
+	return nil;
+}
+
+// writer_write_rune writes a single unicode code point, and returns the number of bytes written with any error
+writer_write_rune :: proc(b: ^Writer, r: rune) -> (size: int, err: io.Error) {
+	if r < utf8.RUNE_SELF {
+		err = writer_write_byte(b, byte(r));
+		size = 0 if err != nil else 1;
+		return;
+	}
+	if b.err != nil {
+		return 0, b.err;
+	}
+
+	buf: [4]u8;
+
+	n := writer_available(b);
+	if n < utf8.UTF_MAX {
+		writer_flush(b);
+		if b.err != nil {
+			return 0, b.err;
+		}
+		n = writer_available(b);
+		if n < utf8.UTF_MAX {
+			// this only happens if the buffer is very small
+			w: int;
+			buf, w = utf8.encode_rune(r);
+			return writer_write(b, buf[:w]);
+		}
+	}
+
+	buf, size = utf8.encode_rune(r);
+	copy(b.buf[b.n:], buf[:size]);
+	b.n += size;
+	return;
+}
+
+// writer_write writes a string into the buffer
+// It returns the number of bytes written
+// If n < len(p), it will return an error explaining why the write is short
+writer_write_string :: proc(b: ^Writer, s: string) -> (int, io.Error) {
+	return writer_write(b, transmute([]byte)s);
+}
+
+// writer_read_from is to support io.Reader_From types
+// If the underlying writer supports the io,read_from, and b has no buffered data yet,
+// this procedure calls the underlying read_from implementation without buffering
+writer_read_from :: proc(b: ^Writer, r: io.Reader) -> (n: i64, err: io.Error) {
+	if b.err != nil {
+		return 0, b.err;
+	}
+	if writer_buffered(b) == 0 {
+		if w, cerr := io.to_reader_from(b.wr); cerr != nil {
+			n, err = io.read_from(w, r);
+			b.err = err;
+			return;
+		}
+	}
+
+	for {
+		if writer_available(b) == 0 {
+			if ferr := writer_flush(b); ferr != nil {
+				return n, ferr;
+			}
+		}
+		m: int;
+		nr := 0;
+		for nr < MAX_CONSECUTIVE_EMPTY_READS {
+			m, err = io.read(r, b.buf[b.n:]);
+			if m != 0 || err != nil {
+				break;
+			}
+			nr += 1;
+		}
+		if nr == MAX_CONSECUTIVE_EMPTY_READS {
+			return n, .No_Progress;
+		}
+		b.n += m;
+		n += i64(m);
+		if err != nil {
+			break;
+		}
+	}
+
+	if err == .EOF {
+		if writer_available(b) == 0 {
+			err = writer_flush(b);
+		} else {
+			err = nil;
+		}
+	}
+	return;
+}
+
+
+
+// writer_to_stream converts a Writer into an io.Stream
+writer_to_stream :: proc(b: ^Writer) -> (s: io.Stream) {
+	s.stream_data = b;
+	s.stream_vtable = _writer_vtable;
+	return;
+}
+
+
+
+@(private)
+_writer_vtable := &io.Stream_VTable{
+	impl_destroy = proc(s: io.Stream) -> io.Error {
+		b := (^Writer)(s.stream_data);
+		writer_destroy(b);
+		return nil;
+	},
+	impl_flush = proc(s: io.Stream)  -> io.Error {
+		b := (^Writer)(s.stream_data);
+		return writer_flush(b);
+	},
+	impl_write = proc(s: io.Stream, p: []byte) -> (n: int, err: io.Error) {
+		b := (^Writer)(s.stream_data);
+		return writer_write(b, p);
+	},
+	impl_write_byte = proc(s: io.Stream, c: byte) -> io.Error {
+		b := (^Writer)(s.stream_data);
+		return writer_write_byte(b, c);
+	},
+	impl_write_rune = proc(s: io.Stream, r: rune) -> (int, io.Error) {
+		b := (^Writer)(s.stream_data);
+		return writer_write_rune(b, r);
+	},
+	impl_read_from = proc(s: io.Stream, r: io.Reader) -> (n: i64, err: io.Error) {
+		b := (^Writer)(s.stream_data);
+		return writer_read_from(b, r);
+	},
+};