-/*
- * hbytes raw2h BINARY => hex
- * hbytes h2raw HEX => binary
- *
- * hbytes length VALUE => count
- * hbytes prepend VAR [VALUE ...] = set VAR [concat VALUE ... $VAR]
- * hbytes append VAR [VALUE ...] = set VAR [concat $VAR VALUE ...]
- * hbytes concat VAR [VALUE ...] = set VAR [concat VALUE ...]
- * hbytes unprepend VAR PREFIXLENGTH => prefix (removed from VAR)
- * hbytes unappend VAR SUFFIXLENGTH => suffix (removed from VAR)
- * hbytes chopto VAR NEWVARLENGTH => suffix (removed from VAR)
- * (too short? error)
- *
- * hbytes range VALUE START SIZE => substring (or error)
- * hbytes overwrite VAR START VALUE
- * hbytes trimleft VAR removes any leading 0 octets
- * hbytes repeat VALUE COUNT => COUNT copies of VALUE
- * hbytes zeroes COUNT => COUNT zero bytes
- * hbytes random COUNT => COUNT random bytes
- * hbytes xor VAR VALUE $VAR (+)= VALUE
- *
- * hbytes ushort2h LONG => LONG must be <2^16, returns as hex
- * hbytes h2ushort HEX => |HEX| must be 2 bytes, returns as ulong
- *
- * hbytes compare A B
- * => -2 A is lexically earlier than B and not a prefix of B (A<B)
- * -1 A is prefix of B but not equal (A<B)
- * 0 A == B
- * +1 A is B plus a nonempty suffix (ie, A has B as a prefix)
- * +2 A is lexically later than B and does not have B as a prefix
- *
- * hbytes pad pa|ua VAR ALG METH [METHARGS] => worked? (always 1 for p)
- * hbytes pad pn|un VAR BS METH [METHARGS] => worked? (always 1 for p)
- * hbytes pad pa|pn VAR ALG|BS pkcs5 => 1
- * hbytes pad ua|un VAR ALG|BS pkcs5 => worked?
- * hbytes pad pa|pn VAR ALG|BS rfc2406 NXTHDR => 1
- * hbytes pad ua|un VAR ALG|BS rfc2406 NXTHDRVAR => worked?
- *
- * hbytes blockcipher d|e VAR ALG KEY MODE [IV] => IV
- * hbytes blockcipher mac MSG ALG KEY MODE IV => final block
- * hbytes blockcipher prop PROPERTY ALG => property value
- *
- * hbytes hash ALG MESSAGE => hash
- * hbytes hmac ALG MESSAGE KEY [MACLENGTH] => mac
- * hbytes hash-prop PROPERTY ALG => property value
- *
- * ulong ul2int ULONG => INT can fail if >INT_MAX
- * ulong int2ul INT => ULONG can fail if <0
- * ulong mask A B => A & B
- * ulong add A B => A + B (mod 2^32)
- * ulong subtract A B => A - B (mod 2^32)
- * ulong compare A B => 0 -1 (A<B) +1 (A>B)
- * ulong shift l|r ULONG BITS fails if BITS >32
- *
- * ulong ul2bitfields VALUE [SIZE TYPE [TYPE-ARG...] ...] => 0/1
- * ulong bitfields2ul BASE [SIZE TYPE [TYPE-ARG...] ...] => ULONG
- * goes from left (MSbit) to right (LSbit) where
- * SIZE is size in bits
- * TYPE [TYPE-ARGS...] is as below
- * zero
- * ignore
- * fixed ULONG-VALUE
- * uint VARNAME/VALUE (VARNAME if ul2bitfields;
- * ulong VARNAME/VALUE VALUE if bitfields2ul)
- *
- * hbytes mask-map lookup MAP-VAR ADDRESS [DEFAULT] => DATA
- * error on missing default or if address too short
- * hbytes mask-map amend MAP-VAR PREFIX PREFIX-LENGTH DATA
- * a maskmap MAP is [list [list PREFIX PREFIX-LENGTH DATA]] sorted
- * first by descending PREFIX-LENGTH and then by ascending PREFIX
- * each PREFIX _in the map_ is truncated to the shortest number of
- * pairs of hex digits which can represent it
- *
- * Error codes
- *
- * HBYTES BLOCKCIPHER CRYPTFAIL CRYPT block cipher mode failed somehow (!)
- * HBYTES BLOCKCIPHER CRYPTFAIL MAC HMAC failed somehow (!)
- * HBYTES BLOCKCIPHER LENGTH block cipher input has unsuitable length
- * HBYTES BLOCKCIPHER PARAMS key or iv not suitable
- * HBYTES HMAC PARAMS key, input or output size not suitable
- * HBYTES LENGTH OVERRUN block too long
- * HBYTES LENGTH RANGE input length or offset is -ve or silly
- * HBYTES LENGTH UNDERRUN block too short (or offset too big)
- * HBYTES LENGTH MISMATCH when blocks must be exactly same length
- * HBYTES SYNTAX supposed hex block had wrong syntax
- * HBYTES VALUE OVERFLOW value to be conv'd to hex too big/long
- * HBYTES MASKMAP SYNTAX LLENGTH value for mask-map entry not llength==3
- * HBYTES MASKMAP SYNTAX UNDERRUN value for mask-map entry hex too short
- * HBYTES MASKMAP SYNTAX OVERRUN actual mask-map entry hex too short
- * HBYTES MASKMAP SYNTAX ORDER actual mask-map is disordered
- * HBYTES MASKMAP SYNTAX EXCLBITS mask-map has 1-bits outside prefix len
- * SOCKADDR AFUNIX LENGTH path for AF_UNIX socket too long
- * SOCKADDR SYNTAX IPV4 bad IPv4 socket address &/or port
- * SOCKADDR SYNTAX OTHER bad socket addr, couldn't tell what kind
- * ULONG BITCOUNT NEGATIVE -ve bitcount specified where not allowed
- * ULONG BITCOUNT OVERRUN attempt to use more than 32 bits
- * ULONG BITCOUNT UNDERRUN bitfields add up to less than 32
- * ULONG VALUE NEGATIVE attempt convert -ve integers to ulong
- * ULONG VALUE OVERFLOW converted value does not fit in result
- * TUNTAP IFNAME LENGTH tun/tap interface name too long
- * TUNTAP MTU OVERRUN tun/tap mtu limited to 2^16 bytes
- *
- * Refs: HMAC: RFC2104
- */