Reseek when write
MODIFY
mrblib/io.rb
mrblib/io.rb
@@ -123,6 +123,10 @@ class IO
def write(string)
str = string.is_a?(String) ? string : string.to_s
return str.size unless str.size > 0
+ if 0 < @buf.length
+ # reset real pos ignore buf
+ seek(pos, SEEK_SET)
+ end
len = syswrite(str)
@pos += len
len

MODIFY
test/io.rb
test/io.rb
@@ -181,6 +181,16 @@ assert('IO#write', '15.2.20.5.20') do
io = IO.open(IO.sysopen($mrbtest_io_wfname))
assert_equal 0, io.write("")
io.close
+
+ io = IO.open(IO.sysopen($mrbtest_io_wfname, "r+"), "r+")
+ assert_equal 7, io.write("abcdefg")
+ io.rewind
+ assert_equal "ab", io.read(2)
+ assert_equal 3, io.write("123")
+ io.rewind
+ assert_equal "ab123fg", io.read
+ io.close
+
true
end

Reseek when write