Hex To Decimal and Decimal to Hex

[MrTAToad]

No checking is done with the conversion from hex to decimal to make sure the passed string is a valid hex character.

Code (glbasic) Select Expand


// --------------------------------- //
// Project: HexADecimal
// Start: Tuesday, March 03, 2009
// IDE Version: 6.174

DEBUG "Hex : "+decToHex$(255,4)+"\n"
DEBUG "Dec : "+hexToDec("FFFF")+"\n"
END

FUNCTION decToHex$:value%,length%=4
LOCAL digit%
LOCAL temp%
LOCAL result$

IF length%<=0
RETURN "0"
ENDIF

result$=""
FOR digit%=length% TO 1 STEP -1
temp%=MOD(value%,16)
IF temp%<10
result$=CHR$(temp%+48)+result$
ELSE
result$=CHR$((temp%-10)+65)+result$
ENDIF

value%=value%/16
NEXT

RETURN result$
ENDFUNCTION

FUNCTION hexToDec%:hex$
LOCAL i%
LOCAL j%
LOCAL loop%

i%=0
j%=0
FOR loop%=0 TO LEN(hex$)-1
i%=ASC(MID$(hex$,loop%,1))-48
IF 9<i%
DEC i%,7
ENDIF

j%=j%*16
j%=bOR(j%,bAND(i,15))
NEXT

RETURN j
ENDFUNCTION


[Kitty Hello]

Very nice!

[MrTAToad]

Thanks!

[ketil]

It's cool, but why not just go inline C and sprintf or something ?

[Moru]

Because that would exclude all GLBasic users that doesn't have the full package.

[ketil]

Ahhh ... didn't think about that.

[Qedo]

the old 2009 hexToDec function fails with value xFFFFFFFF because it returns value -1 instead of 4294967295.
This instead is the one that returns the correct value. For those who had used the old one please check
ad maiora

FUNCTION hexToDec#:_HEX$
LOCAL i%=0
LOCAL j#=0
LOCAL loop%
   _HEX$=UCASE$(_HEX$)
   LOCAL start%=LEN(_HEX$)-1
   FOR loop%=start TO 0 STEP-1
      i=ASC(MID$(_HEX$,loop,1))-48   //0=48 A=65
      IF i>9
         DEC i,7
      ENDIF
      j=j+i*POW(16,start-loop)
   NEXT
RETURN j
ENDFUNCTION

[Kitty Hello]

There is a builtins HEX$(), are you aware of that?

[Qedo]

HEX$() ? I thought it only transforms from decimal to hexadecimal.
Or am I wrong?
I need the opposite. HEX2DEC

[Kitty Hello]

Ah. Try this:

Code (glbasic) Select Expand


IMPORT "C" int strtol(const char* str, int endptr, int base)
LOCAL str$ = "ff"
LOCAL n% = strtol(str$, 0, 16)


[Qedo]

Thanks Gernot for the great help  , However for high hex, like 0xFFFFFFFF the strtol function overflows. It seems to be better strtoul.
ad maiora

a#=hex2dec("F234FFF0")
PRINT a,0,0
SHOWSCREEN
MOUSEWAIT
END

IMPORT "C" unsigned long strtoul(const char* str, int endptr, int base)
FUNCTION hex2dec#: str$
   LOCAL n# = strtoul(str$, 0, 16)
   RETURN n
ENDFUNCTION