peekNextDigit() returns an int, so it can return -1 in addition to all
256 possible bytes. By putting the result in a signe char, all bytes
over 128 will be interpreted as "no bytes available". Furthermore, it
seems that on SAM "char" is unsigned by default, causing the
"if (c < 0)" line a bit further down to always be false.
Using an int is more appropriate.
A different fix for this issue was suggested in #1399. This fix helps
towards #1728.
This isn't necessarily a particularly efficient implementation (it
allocates memory one character at a time and so may lead to
fragmentation) but it seems to work.
http://code.google.com/p/arduino/issues/detail?id=454
This from Michael's TextFinder library, incorporated into the Stream class: find(), findUntil(), parseInt(), parseFloat(), readChars(), readCharsUntil(), readCharsBetween(), setTimeout().
Matthijs Kooijman
David A. Mellis