Code archives/Algorithms/hex2dec
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| The hexidecimal number can be in the Blitz format "$ffff" or just vanilla "FFFF" format. The function is case-insensitive. |
Function hex2dec%(hex_number$) ; Converts the supplied hex number into a decimal number ; If hex_number isn't a valid hex number, then returns -1 ; written by Matt Burns (Blu_Matt / matt@blis.co.uk) Local the_hex$=Upper(Trim(hex_number$)) ; the hex number Local base_power%=0 ; the current base power Local base%=16 ; the base to convert from Local the_dec%=0 ; the decimal representation Local chars%=0 Local hex_length%=Len(the_hex$) ; current length of the hex If Left(the_hex$,1)="$" Then ; removes any leading "$" the_hex$=Right(the_hex$,hex_length%-1) EndIf hex_length%=Len(the_hex$) ; current length of the hex Local chars_left%=hex_length% ; current number of chars left Local hex_left$=the_hex$ ; current hex left Repeat current_hex$=Right(hex_left$,1) ; gets the current hex char If ((Asc(current_hex$)>=Asc("0")) And (Asc(current_hex$)<=Asc("9"))) Then hex_dec%=current_hex$ ; digit 0-9 ElseIf ((Asc(current_hex$)>=Asc("A")) And (Asc(current_hex$)<=Asc("F"))) Then hex_dec%=Asc(current_hex$)-55 ; char A-F Else Return -1 ; found an illegal character, aborting... EndIf the_dec%=the_dec%+((base%^base_power%)*hex_dec%) ; add the local hex digit to the total base_power%=base_power%+1 ; increase the base power chars_left%=chars_left%-1 ; reduce the number of chars left hex_left$=Left(hex_left$,chars_left%) ; sets the remainder Until chars_left%=0 Return the_dec% ; return the result End Function ; testing, 1, 2, 3... Print hex2dec("$ff") ; = 255 Print hex2dec("100") ; = 256 |