Merge: Performance improvement in read_all_bytes

As @privat notified me of yesterday, a lot of time is wasted in read_all by boxing and unboxing bytes when doing the infamous `_buffer.add` operation in `read_all_bytes`.

This PR removes the boxing operations by bulk-writing a NativeString to a Bytes.
The buffer on files is also tenfold-bigger, which cuts I/O times while still retaining a reasonable size.

# Performances

On the Batmobile™

## Valgrind

Before:
standard___standard__BufferedReader___Reader__read_all_bytes: 90.816 MIr
After:
standard___standard__BufferedReader___Reader__read_all_bytes: 7.596 MIr

## ./ncall-best

Before
user	0m4.316s
After
user	0m4.182s

Close #1298

Pull-Request: #1636
Reviewed-by: Jean Privat <jean@pryen.org>
Reviewed-by: Alexandre Terrasa <alexandre@moz-code.org>

diff --git a/lib/standard/file.nit b/lib/standard/file.nit
index e5fc85b..aba34e8 100644 (file)
--- a/lib/standard/file.nit
+++ b/lib/standard/file.nit
@@ -156,7 +156,7 @@ class FileReader
        init open(path: String)
        do
                self.path = path
-               prepare_buffer(10)
+               prepare_buffer(100)
                _file = new NativeFile.io_open_read(path.to_cstring)
                if _file.address_is_null then
                        last_error = new IOError("Cannot open `{path}`: {sys.errno.strerror}")

diff --git a/lib/standard/stream.nit b/lib/standard/stream.nit
index ce6e9b3..0eabcba 100644 (file)
--- a/lib/standard/stream.nit
+++ b/lib/standard/stream.nit
@@ -518,14 +518,13 @@ abstract class BufferedReader
        do
                if last_error != null then return new Bytes.empty
                var s = new Bytes.with_capacity(10)
+               var b = _buffer
                while not eof do
                        var j = _buffer_pos
                        var k = _buffer_length
-                       while j < k do
-                               s.add(_buffer[j])
-                               j += 1
-                       end
-                       _buffer_pos = j
+                       var rd_sz = k - j
+                       s.append_ns_from(b, rd_sz, j)
+                       _buffer_pos = k
                        fill_buffer
                end
                return s