Do we have built-in hexadecimal to binary conversion in tcl?

Question

I need help to figure out a built-in hexadecimal to binary conversion in Tcl; I am currently using TCL 8.5. Similar to hex to dec conversion, do we have for hex to bin or any one liner syntax for doing the conversion?

Accepted Answer

I'm not quite sure what you mean by binary; do you mean a sequences of bytes or a sequence of `0` and `1` characters?

Converting from hexadecimal to a byte sequence (which is a string that happens to only have characters in the range `\u0000` to `\u00ff`) is done with the `binary format` command:

```
set hex "61626364"
set bytes [binary format H* $hex]
puts $bytes
# Prints 'abcd'
```

To convert to a sequence of digits that represent bits, you convert to a binary string as above and then use `binary scan` to convert back:

```
set hex "61626364"
# No option to get the value without writing it to a variable
binary scan [binary format H* $hex] B* bits
puts $bits
# Prints '01100001011000100110001101100100'
```

All the above work on Tcl 8.5. Note that you need to use upper case `H*` and `B*` or the code will try to do something which it claims is “little endian” (and might actually be so) and which confuses me a lot.

Do we have built-in hexadecimal to binary conversion in tcl?

Solution

Problem