Fixed page down support, added page up support

editor.c

@@ -87,9 +87,10 @@ void buffer_left(Buffer* buffer) {
 
 
 void scroll_page_down_handler(Buffer* buffer) {
-	while (*(buffer->start + index_to_start) != '\n') {
+	while (*(buffer->text + index_to_start) != '\n') {
 		index_to_start++;
 	}
+	index_to_start++;
 }
 
 void page_down_handler(Buffer* buffer) {
@@ -115,6 +116,36 @@ void page_down_handler(Buffer* buffer) {
 
 }
 
+
+void scroll_page_up_handler(Buffer* buffer) {
+	for (int i=0;i<2;i++) { /* we need to encounter two 'newlines' before we stop */
+		while((*(buffer->text + index_to_start) != '\n') && (index_to_start >= 0)) {
+			index_to_start--;
+		}
+	}
+
+	index_to_start++;
+}
+
+void page_up_handler(Buffer* buffer) {
+	while((*(buffer->start - 1) != '\n') && (buffer->text != buffer->start)) { 
+			buffer_left(buffer);
+	}
+
+
+	buffer_left(buffer);
+
+	while((*(buffer->start - 1) != '\n') && (buffer->text != buffer->start)) {
+			buffer_left(buffer);
+	}
+
+
+	if ((getcury(stdscr) == 0) && (index_to_start > 0)) {
+		scroll_page_up_handler(buffer);
+	}
+
+}
+
 void init_curses() {
 	initscr();
 	noecho();
@@ -218,6 +249,10 @@ int main(int argc, char** argv) {
 				page_down_handler(buffer);			
 				break;
 
+			case KEY_PPAGE:
+				page_up_handler(buffer);
+				break;
+
 			default:
 				buffer_insert(ch,buffer);