jodd-joy/src/main/java/jodd/joy/page/PageData.java
public static int calcFirstItemIndexOfPage(int page, final int pageSize, final int total) {
		if (total == 0) {
			return 0;
		}
		if (page < 1) {
			page = 1;
		}
		int first = (page - 1) * pageSize;
		if (first >= total) {
			first = ((total - 1) / pageSize) * pageSize;	// first item on the last page
		}
		return first;
	}
public static int calcFirstItemIndexOfPage(int page, final int pageSize, final int total) {
		if (total == 0) {
			return 0;
		}
		if (page < 1) {
			page = 1;
		}
		int first = (page - 1) * pageSize;
		if (first >= total) {
			first = ((total - 1) / pageSize) * pageSize;	// first item on the last page
		}
		return first;
	}
Calculates the first item index of requested page.