From 185465df3d6a7a83f3c0cfa0b8169d37039e9f37 Mon Sep 17 00:00:00 2001
From: Michael Drake <tlsa@netsurf-browser.org>
Date: Sun, 17 Jan 2010 09:57:25 +0000
Subject: [PATCH] Order containing block's list of floats in descending order
 of the y-position of their base. Make find_sides() stop searching, after
 floats are above the range we're interested in. (351s --> 73s on ix for
 haveproblems/really-slow-float-table2.html)

svn path=/trunk/netsurf/; revision=9846
---
 render/layout.c | 40 +++++++++++++++++++++++++++++++++++++---
 1 file changed, 37 insertions(+), 3 deletions(-)

diff --git a/render/layout.c b/render/layout.c
index 45a075750..0cc7b6d68 100644
--- a/render/layout.c
+++ b/render/layout.c
@@ -1673,7 +1673,7 @@ void find_sides(struct box *fl, int y0, int y1,
 	int fy0, fy1, fx0, fx1;
 	LOG(("y0 %i, y1 %i, x0 %i, x1 %i", y0, y1, *x0, *x1));
 	*left = *right = 0;
-	for (; fl; fl = fl->next_float) {
+	for (; fl && fl->y + fl->height >= y0; fl = fl->next_float) {
 		fy0 = fl->y;
 		fy1 = fl->y + fl->height;
 		if (y0 < fy1 && fy0 <= y1) {
@@ -2300,8 +2300,42 @@ bool layout_line(struct box *first, int *width, int *y,
 				box_dump(stderr, cont, 0);
 				assert(0);
 			}
-			b->next_float = cont->float_children;
-			cont->float_children = b;
+			/* Insert float into containing block's list of
+			 * floats. (List sorted by y-position of bottom of
+			 * float, in descending order.) */
+			if (!cont->float_children) {
+				/* First float child */
+				cont->float_children = b;
+				b->next_float = NULL;
+			} else if (b->y + b->height >= cont->float_children->y +
+					cont->float_children->height) {
+				/* Float is positioned lower or at same level
+				 * as first float in list */
+				b->next_float = cont->float_children;
+				cont->float_children = b;
+			} else {
+				/* Find place in list */
+				struct box *t;
+				for (t = cont->float_children;
+						t && t->next_float;
+						t = t->next_float) {
+					if (b->y + b->height >=
+							t->next_float->y +
+							t->next_float->height) {
+						/* Float positioned mid-list */
+						b->next_float = t->next_float;
+						t->next_float = b;
+						break;
+					} else if (!t->next_float->next_float) {
+						/* Float positioned last in
+						 * list */
+						t->next_float->next_float = b;
+						b->next_float = NULL;
+						break;
+					}
+				}
+			}
+
 			split_box = 0;
 		}
 	}