AutoHotkey - limiting the number and type of characters taken from the string - autohotkey

Question

I have an ahk script for an IRC client which after entering nick!ident#host into the text field and pressing F4 decrypts the ident which is the encrypted form of the IP address:
F4::
Clipboard =
Send ^a^x
ClipWait, 0
If ErrorLevel
MsgBox, 48, Error, An error occurred while waiting for the clipboard. Aborting.
Else Clipboard := decode(SubStr(Clipboard, -15, -8))
Return
decode(str) {
Static code := " " "
( LTrim Join`s
00 0x 02 03 04 0z 06 01 08 09 0B 0b 0c 0d 0e 0H x0 xx x2 x3 x4 xz x6 x1 x8 x9 xB xb xc xd xe xH 20 2x
22 23 24 2z 26 21 28 29 2B 2b 2c 2d 2e 2H 30 3x 32 33 34 3z 36 31 38 39 3B 3b 3c 3d 3e 3H 40 4x 42 43
44 4z 46 41 48 49 4B 4b 4c 4d 4e 4H z0 zx z2 z3 z4 zz z6 z1 z8 z9 zB zb zc zd ze zH 60 6x 62 63 64 6z
66 61 68 69 6B 6b 6c 6d 6e 6H 10 1x 12 13 14 1z 16 11 18 19 1B 1b 1c 1d 1e 1H 80 8x 82 83 84 8z 86 81
88 89 8B 8b 8c 8d 8e 8H 90 9x 92 93 94 9z 96 91 98 99 9B 9b 9c 9d 9e 9H B0 Bx B2 B3 B4 Bz B6 B1 B8 B9
BB Bb Bc Bd Be BH b0 bx b2 b3 b4 bz b6 b1 b8 b9 bB bb bc bd be bH c0 cx c2 c3 c4 cz c6 c1 c8 c9 cB cb
cc cd ce cH d0 dx d2 d3 d4 dz d6 d1 d8 d9 dB db dc dd de dH e0 ex e2 e3 e4 ez e6 e1 e8 e9 eB eb ec ed
ee eH H0 Hx H2 H3 H4 Hz H6 H1 H8 H9 HB Hb Hc Hd He HH
)"
Loop, % StrLen(str) / 2
new .= "." Round((Instr(code, " " SubStr(str, 2 * A_Index - 1, 2), True) - 1) / 3)
Return SubStr(new, 2)
}
Decryption is performed according to the following key:
https://pastebin.com/raw/P8cQtH2v
For example, for user data asdf!~z3040d4B#webchat will decrypt the ident from z3040d4B as 83.4.13.75 and copies this value to the clipboard.
But there are cases when the encoded form of the IP (ident) is longer or shorter than 8 characters or contains characters that aren't in the decryption key. Then it's impossible to decode the IP correctly. So I would like the script to copy the decryption result to the clipboard only if the retrieved string (between ! and #, omitting the ~ sign if present) is 8 characters long and contains the characters contained in the key I entered. Otherwise, the script should clear the clipboard. How to do it?

Answer 1

A regex match approach with e.g the regex !~?[A-z\d]{8}# is surely most convenient:
F4::
Clipboard := ""
SendInput, ^a^x
ClipWait, 0
if (ErrorLevel)
MsgBox, 48, Error, An error occurred while waiting for the clipboard. Aborting.
else if (Clipboard ~= "!~?[A-z\d]{8}#")
Clipboard := decode(SubStr(Clipboard, -15, -8))
else
Clipboard := ""
Return
decode(str)
{
static code := " " "
( LTrim Join`s
00 0x 02 03 04 0z 06 01 08 09 0B 0b 0c 0d 0e 0H x0 xx x2 x3 x4 xz x6 x1 x8 x9 xB xb xc xd xe xH 20 2x
22 23 24 2z 26 21 28 29 2B 2b 2c 2d 2e 2H 30 3x 32 33 34 3z 36 31 38 39 3B 3b 3c 3d 3e 3H 40 4x 42 43
44 4z 46 41 48 49 4B 4b 4c 4d 4e 4H z0 zx z2 z3 z4 zz z6 z1 z8 z9 zB zb zc zd ze zH 60 6x 62 63 64 6z
66 61 68 69 6B 6b 6c 6d 6e 6H 10 1x 12 13 14 1z 16 11 18 19 1B 1b 1c 1d 1e 1H 80 8x 82 83 84 8z 86 81
88 89 8B 8b 8c 8d 8e 8H 90 9x 92 93 94 9z 96 91 98 99 9B 9b 9c 9d 9e 9H B0 Bx B2 B3 B4 Bz B6 B1 B8 B9
BB Bb Bc Bd Be BH b0 bx b2 b3 b4 bz b6 b1 b8 b9 bB bb bc bd be bH c0 cx c2 c3 c4 cz c6 c1 c8 c9 cB cb
cc cd ce cH d0 dx d2 d3 d4 dz d6 d1 d8 d9 dB db dc dd de dH e0 ex e2 e3 e4 ez e6 e1 e8 e9 eB eb ec ed
ee eH H0 Hx H2 H3 H4 Hz H6 H1 H8 H9 HB Hb Hc Hd He HH
)"
Loop, % StrLen(str) / 2
{
if (!InStr(code, block := " " SubStr(str, 2 * A_Index - 1, 2), true))
return ""
new .= "." Round((InStr(code, block, true) - 1) / 3)
}
return SubStr(new, 2)
}
~=(docs) is the RegExMatch()(docs) shorthand.