cpbuffer extract(): use integer arithmetic instead of char pointer.
cpbuffer extract(): use integer arithmetic instead of char pointer.

The method is designed to extract data to an arbitrary type, and while
char * should probably be safe to do that with, conversion to char * is
not specified in C++ as it is in C, and compilers are becoming more
aggressive.

davmac314/dinit,davmac314/dinit,davmac314/dinit