Code to convert a string of '0's and '1's to the corresponding hex number, and back. Note that we are _not_ talking about binary strings. Code by Jeff Hobbs, from his bag of utilities.
Tcl, 60 lines
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Copy to clipboard1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 | # bin2hex --
# converts binary to hex number
# Arguments:
# bin number in binary format
# Returns:
# hexadecimal number
#
proc bin2hex bin {
## No sanity checking is done
array set t {
0000 0 0001 1 0010 2 0011 3 0100 4
0101 5 0110 6 0111 7 1000 8 1001 9
1010 a 1011 b 1100 c 1101 d 1110 e 1111 f
}
set diff [expr {4-[string length $bin]%4}]
if {$diff != 4} {
set bin [format %0${diff}d$bin 0]
}
regsub -all .... $bin {$t(&)} hex
return [subst $hex]
}
# hex2bin --
# converts hex number to bin
# Arguments:
# hex number in hex format
# Returns:
# binary number (in chars, not binary format)
#
proc hex2bin hex {
set t [list 0 0000 1 0001 2 0010 3 0011 4 0100 \
5 0101 6 0110 7 0111 8 1000 9 1001 \
a 1010 b 1011 c 1100 d 1101 e 1110 f 1111 \
A 1010 B 1011 C 1100 D 1101 E 1110 F 1111]
regsub {^0[xX]} $hex {} hex
return [string map -nocase $t $hex]
}
# hex2bin-alternate --
# converts hex number to bin
# Arguments:
# hex number in hex format
# Returns:
# binary number (in chars, not binary format)
#
proc bin2hex-alternate bin {
## No sanity checking is done
set t {
0000 0 0001 1 0010 2 0011 3 0100 4
0101 5 0110 6 0111 7 1000 8 1001 9
1010 a 1011 b 1100 c 1101 d 1110 e 1111 f
}
set diff [expr {4-[string length $bin]%4}]
if {$diff != 4} {
set bin [format %0${diff}d$bin 0]
}
return [string map $t $hex]
}
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Bin2Hex is a bit of old-style, with its use of regsub/subst. [string map] can be used for this too. See the alternate implementation.
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bin2hex-alternate has problems. Looks to me like bin2hex-alternate has a couple of problems: