Suppressing UTFException / Squashing Bad Codepoints?

[John Carter]

This frustrated me in Ruby unicode too....

Typically i/o is the ultimate in "untrusted and untrustworthy" sources,
coming usually from systems beyond my control.

Likely to be corrupted, or maliciously crafted, or defective...

Unfortunately not all sequences of bytes are valid UTF8.

Thus inevitably in every collection of inputs there are always going to be
around 1 in a million codepoints resulting in an UTFException thrown.

Alas, I always have to do Regex matches on the other 999999 valid
codepoints.....

Is there a standard recipe in stdio for squashing bad codepoints to some
default?

These days memory is very much larger than most files I want to scan.

So if I was doing this in C I would typically mmap the file PROT_READ |
PROT_WRITE and MAP_PRIVATE then run down the file squashing bad codepoints
and then run down it again matching patterns.

In Ruby I have a horridly inefficient utility....
      def IO.read_utf_8(file)

read(file,:external_encoding=>'ASCII-8BIT').encode('UTF-8',:undef=>:replace)
      end

What is the idiomatic D solution to this conundrum?

-- 
John Carter
Phone : (64)(3) 358 6639
Tait Electronics
PO Box 1645 Christchurch
New Zealand

-- 

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