Re: Convert HTML to String

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billyard wrote:
Giovanni Dicanio wrote:
"billyard" <dmetcalf@xxxxxxxxxxxxxxx> ha scritto nel messaggio news:47688467$0$16093$4c368faf@xxxxxxxxxxxxxxxxx

// Get the next two characters
CString nextTwo = strBody.Mid( startPos + 1, 2 );

// Translate this into the ASCII equivalent?
????

So, is your problem to translate a string of kind "XX" where XX is an hex integer (e.g. "2D") into the corresponding ASCII character?

If so, I would use a code like this (may have errors... not tested on a compiler, I just wrote this on the keyboard and read it again):

The main function is this:

TCHAR AsciiHexToChar(LPCTSTR asciiHexCode)

it converts from the given hex ASCII code string to corresponding ASCII character, e.g.:

AsciiHexToChar( _T("2E") ) returns _T('.')

...if you find the _T() confusing, imagine like this:

AsciiHexToChar( "2E" ) returns '.'

So, in your loop, you could write:

TCHAR ch = AsciiHexToChar( nextTwo );

and ch stores the desidered character.

<code>
// Converts a character storing an hex nibble
// ('0'-'9','a'-'f','A'-'F')
// into its decimal value.
int HexNibbleToInt( TCHAR hexNibble )
{
if ( hexNibble >= _T('0') && hexNibble <= _T('9') )
return (hexNibble - _T('0'));
else if ( hexNibble >= _T('A') && hexNibble <= _T('F') )
return (hexNibble - _T('A')) + 10;
else if ( hexNibble >= _T('a') && hexNibble <= _T('f') )
return (hexNibble - _T('a')) + 10;
else
{
// *** ERROR - invalid character
ASSERT( FALSE );
return -1;
}
}


// Converts ASCII 2-characters hex codes to a single character,
// e.g. "2E" --> '.'
// On bad characters, returns '\0'
TCHAR AsciiHexToChar(LPCTSTR asciiHexCode)
{
int lowNibble;
int highNibble;
int asciiCode;

// Check pointer
ASSERT( asciiHexCode != NULL );

// Check that the strings has two characters
ASSERT( asciiHexCode[0] != _T('\0') );
ASSERT( asciiHexCode[1] != _T('\0') );
ASSERT( asciiHexCode[2] == _T('\0') );


// High nibble
highNibble = HexNibbleToInt( asciiHexCode[0] ) * 16;
if ( highNibble < 0 )
return '\0'; // bad nibble

// Low nibble
lowNibble = HexNibbleToInt( asciiHexCode[1] );
if ( lowNibble < 0 )
return '\0'; // bad nibble

// Convert to character using ASCII
asciiCode = highNibble * 16 + lowNibble;

return (TCHAR)asciiCode;
}

</code>


Giovanni


Giovanni - Nicely done code that works great for me. Only one minor problem. In the code above, you multiply highNibble by 16 two times. Other than that, it works exactly as you said it would.

This line:

// Convert to character using ASCII
asciiCode = highNibble * 16 + lowNibble;

Should read:
asciiCode = highNibble + lowNibble;

btw - I'm looking forward to the day I could write code like that and
actually have it compile the first go around!
.

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