From: Jean Privat <jean@pryen.org>
Date: Thu, 14 May 2015 23:35:54 +0000 (-0400)
Subject: Merge: Read char
X-Git-Tag: v0.7.5~53
X-Git-Url: http://nitlanguage.org

Merge: Read char

Semantics have been changed, before this PR, read_char was used to read a single byte and return -1 if EOF or timeout.

Since a Byte can have a value of -1, it is changed here:

* `read_char` now returns a Char (which, for the moment, is a byte, but this will change once UTF-8 is properly supported), and returns null on EOF or timeout
* `read_byte` has more or less the semantics of the old read_char, but returns null on EOF instead of -1 for the reasons mentioned earlier which could induce a wrong assumption about the state of the Stream

Edit: Still related to #1309

Pull-Request: #1334
Reviewed-by: Alexandre Terrasa <alexandre@moz-code.org>
Reviewed-by: Jean Privat <jean@pryen.org>
---

506f4b1efdd9d548becca066036e3cd5c1456a09
diff --cc lib/standard/stream.nit
index 4ad6af1,884368d..6b6d3fe
--- a/lib/standard/stream.nit
+++ b/lib/standard/stream.nit
@@@ -382,44 -383,28 +383,56 @@@ abstract class BufferedReade
  	super Reader
  	redef fun read_char
  	do
- 		if last_error != null then return -1
+ 		if last_error != null then return null
  		if eof then
  			last_error = new IOError("Stream has reached eof")
- 			return -1
+ 			return null
  		end
- 		var c = _buffer.chars[_buffer_pos]
+ 		var c = _buffer[_buffer_pos]
  		_buffer_pos += 1
- 		return c.ascii
+ 		return c
+ 	end
+ 
+ 	redef fun read_byte
+ 	do
+ 		if last_error != null then return null
+ 		if eof then
+ 			last_error = new IOError("Stream has reached eof")
+ 			return null
+ 		end
+ 		var c = _buffer[_buffer_pos].ascii
+ 		_buffer_pos += 1
+ 		return c
  	end
  
 +	# Peeks up to `n` bytes in the buffer, returns an empty string on EOF
 +	#
 +	# The operation does not consume the buffer
 +	#
 +	# ~~~nitish
 +	# 	var x = new FileReader("File.txt")
 +	#	assert x.peek(5) == x.read(5)
 +	# ~~~
 +	fun peek(i: Int): String do
 +		if eof then return ""
 +		var b = new FlatBuffer.with_capacity(i)
 +		while i > 0 and not eof do
 +			b.add _buffer[_buffer_pos]
 +			_buffer_pos += 1
 +			i -= 1
 +		end
 +		var nbuflen = b.length + (_buffer.length - _buffer_pos)
 +		var nbuf = new FlatBuffer.with_capacity(nbuflen)
 +		nbuf.append(b)
 +		while _buffer_pos < _buffer.length do
 +			nbuf.add(_buffer[_buffer_pos])
 +			_buffer_pos += 1
 +		end
 +		_buffer_pos = 0
 +		_buffer = nbuf
 +		return b.to_s
 +	end
 +
  	redef fun read(i)
  	do
  		if last_error != null then return ""