range_bufinbuf - range check for buf in buffer

       range_bufinbuf checks that the buffer buf2[0..len2-1] lies entirely in buf1[0..len1].

       If   the  buffer  is  0-terminated  and  you  don't  know  the  length  beforehand,  use  range_strinbuf,
       range_str2inbuf or range_str4inbuf instead.

       range_bufinbuf - range check for buf in buffer

       If one of the buffers is implausible (buf is NULL or buf+len has an integer overflow), return 0.

       If the buf2[0..len2-1] lies before or after buf1[0..len1-1], return 0.

       Otherwise, return 1.

rangecheck(3)

                                                                                               range_bufinbuf(3)

#include<libowfat/rangecheck.h>

       int range_bufinbuf(const void* buf1,size_t len1,
                          const void* buf2,size_t len2);