BGD_DECLARE(void) gdImageFillToBorder (gdImagePtr im, int x, int y, int border, int color)
{
	int lastBorder;
	/* Seek left */
	int leftLimit, rightLimit;
	int i;
	int restoreAlphaBleding;

	if (border < 0 || color < 0) {
		/* Refuse to fill to a non-solid border */
		return;
	}

	if (!im->trueColor) {
		if ((color > (im->colorsTotal - 1)) || (border > (im->colorsTotal - 1))) {
			return;
		}
    }

	leftLimit = (-1);

	restoreAlphaBleding = im->alphaBlendingFlag;
	im->alphaBlendingFlag = 0;

	if (x >= im->sx) {
		x = im->sx - 1;
	} else if (x < 0) {
		x = 0;
	}
	if (y >= im->sy) {
		y = im->sy - 1;
	} else if (y < 0) {
		y = 0;
	}
	
	for (i = x; (i >= 0); i--) {
		if (gdImageGetPixel (im, i, y) == border) {
			break;
		}
		gdImageSetPixel (im, i, y, color);
		leftLimit = i;
	}
	if (leftLimit == (-1)) {
		im->alphaBlendingFlag = restoreAlphaBleding;
		return;
	}
	/* Seek right */
	rightLimit = x;
	for (i = (x + 1); (i < im->sx); i++) {
		if (gdImageGetPixel (im, i, y) == border) {
			break;
		}
		gdImageSetPixel (im, i, y, color);
		rightLimit = i;
	}
	/* Look at lines above and below and start paints */
	/* Above */
	if (y > 0) {
		lastBorder = 1;
		for (i = leftLimit; (i <= rightLimit); i++) {
			int c;
			c = gdImageGetPixel (im, i, y - 1);
			if (lastBorder) {
				if ((c != border) && (c != color)) {
					gdImageFillToBorder (im, i, y - 1, border, color);
					lastBorder = 0;
				}
			} else if ((c == border) || (c == color)) {
				lastBorder = 1;
			}
		}
	}
	/* Below */
	if (y < ((im->sy) - 1)) {
		lastBorder = 1;
		for (i = leftLimit; (i <= rightLimit); i++) {
			int c = gdImageGetPixel (im, i, y + 1);
			if (lastBorder) {
				if ((c != border) && (c != color)) {
					gdImageFillToBorder (im, i, y + 1, border, color);
					lastBorder = 0;
				}
			} else if ((c == border) || (c == color)) {
				lastBorder = 1;
			}
		}
	}
	im->alphaBlendingFlag = restoreAlphaBleding;
}
The software performs operations on a memory buffer, but it can read from or write to a memory location that is outside of the intended boundary of the buffer.