void bytestring_reverse(unsigned char *dest, unsigned char *from, unsigned long  len);
void bytestring_intersperse(unsigned char *dest, unsigned char *from, unsigned long  len, unsigned char c);
unsigned char bytestring_maximum(unsigned char *p, unsigned long  len);
unsigned char bytestring_minimum(unsigned char *p, unsigned long  len);
unsigned long bytestring_count(unsigned char *p, unsigned long  len, unsigned char w);