CMYK separated images

BOOL fipImage::splitCMYK(fipImage& newc, fipImage& newm, fipImage& newy, fipImage& newk){
	if (_dib){

		if(!FreeImage_HasPixels(_dib)) return FALSE;

		// src image should be CMYK
		FREE_IMAGE_COLOR_TYPE color_type = FreeImage_GetColorType(_dib);
		if (color_type !=FIC_CMYK){
			return FALSE;
		}
		
		FREE_IMAGE_TYPE image_type = FreeImage_GetImageType(_dib);
		unsigned bpp = FreeImage_GetBPP(_dib);

		// allocate a 8-bit dib
		unsigned width  = FreeImage_GetWidth(_dib);
		unsigned height = FreeImage_GetHeight(_dib);

		FIBITMAP *dst[4] = {NULL, NULL, NULL, NULL};

		for (int i = 0; i < 4; ++i){
			dst[i] = FreeImage_Allocate(width, height, 8);
			if(!dst) continue;

			// build a greyscale palette
			RGBQUAD *pal = FreeImage_GetPalette(dst[i]);
			for(int i = 0; i < 256; i++) {
				pal[i].rgbBlue = pal[i].rgbGreen = pal[i].rgbRed = (BYTE)i;
			}
		}
		
		// perform extraction

		int bytespp = bpp / 8;	// bytes / pixel

		for(unsigned y = 0; y < height; y++) {
			BYTE *src_bits = FreeImage_GetScanLine(_dib, y);
			BYTE *c_bits = FreeImage_GetScanLine(dst[0], y);
			BYTE *m_bits = FreeImage_GetScanLine(dst[1], y);
			BYTE *y_bits = FreeImage_GetScanLine(dst[2], y);
			BYTE *k_bits = FreeImage_GetScanLine(dst[3], y);

			for(unsigned x = 0; x < width; x++) {
				c_bits[x] = src_bits[0];
				m_bits[x] = src_bits[1];
				y_bits[x] = src_bits[2];
				k_bits[x] = src_bits[3];
				src_bits += bytespp;
			
			}
		}

		//
		newc = dst[0];
		newm = dst[1];
		newy = dst[2];
		newk = dst[3];

		return (newc.isValid() && newm.isValid() && newy.isValid() && newk.isValid());
	}
	return FALSE;
}