Function V_URLEncodeInternal

src/vrcore/strtools_public.cpp:352–411

----------------------------------------------------------------------------- Purpose: Internal implementation of encode, works in the strict RFC manner, or with spaces turned to + like HTML form encoding. -----------------------------------------------------------------------------

//          with spaces turned to + like HTML form encoding.
//-----------------------------------------------------------------------------
void V_URLEncodeInternal( char *pchDest, int nDestLen, const char *pchSource, int nSourceLen, 
	bool bUsePlusForSpace, std::function< bool(const char)> fnNeedsEscape )
{
	//AssertMsg( nDestLen > 3*nSourceLen, "Target buffer for V_URLEncode should be 3x source length, plus one for terminating null\n" );
	
	int iDestPos = 0;
	for ( int i=0; i < nSourceLen; ++i )
	{
		// worst case we need 3 additional chars
		if( (iDestPos+3) > nDestLen  )
		{
			pchDest[0] = '\0';
//			AssertMsg( false, "Target buffer too short\n" );
			return;
		}

		// We allow only a-z, A-Z, 0-9, period, underscore, and hyphen to pass through unescaped.
		// These are the characters allowed by both the original RFC 1738 and the latest RFC 3986.
		// Current specs also allow '~', but that is forbidden under original RFC 1738.
		if ( fnNeedsEscape( pchSource[i] ) )
		{
			if ( bUsePlusForSpace && pchSource[i] == ' ' )
			{
				pchDest[iDestPos++] = '+';
			}
			else
			{
				pchDest[iDestPos++] = '%';
				uint8_t iValue = pchSource[i];
				if ( iValue == 0 )
				{
					pchDest[iDestPos++] = '0';
					pchDest[iDestPos++] = '0';
				}
				else
				{
					char cHexDigit1 = cIntToHexDigit( iValue % 16 );
					iValue /= 16;
					char cHexDigit2 = cIntToHexDigit( iValue );
					pchDest[iDestPos++] = cHexDigit2;
					pchDest[iDestPos++] = cHexDigit1;
				}
			}
		}
		else
		{
			pchDest[iDestPos++] = pchSource[i];
		}
	}

	if( (iDestPos+1) > nDestLen )
	{
		pchDest[0] = '\0';
		//AssertMsg( false, "Target buffer too short to terminate\n" );
		return;
	}

	// Null terminate