Refactor so that all possible matches of y in x are matched at once.

Author: Lethja

xtra/DIFF.LUA

@@ -15,24 +15,23 @@ local function diff_u(fn1,fn2)
 		local function li(fn,o,l)f,e=io.open(fn,"rb")if not f then return nil,e end f:seek(S,o)local g=f:read(l)f:close()return g end
 		b1,e,b2=li(fn1,o1,l1)if not b1 then error(e)end b2,e=li(fn2,o2,l2)if not b2 then error(e)end return b1==b2 end
 	h,w,m=#f1//ps,#f2//ps,{}
+	local ly,n=1
 	for x=1,h do
 		local b={}
 		local function inList(v)for k,p in ipairs(b)do if v==p then return k end end end
-		for y=1,w do if cmp(x,y)then table.insert(b,y)end end
-		if #m>0 and m[#m].x+m[#m].l==x then
-			if inList(m[#m].y+m[#m].l) then
-				m[#m].l=m[#m].l+1
-			else
-				--TODO: Know where to run the next block
-				local n=inList(m[#m].y+m[#m].l)
-				if n then
-					table.insert(m,{y=b[n],x=x,l=1})
+		for y=ly,w do if cmp(x,y)then table.insert(b,y)end end
+		if #b>0 then
+			if #m>0 then
+				if m[#m].x+m[#m].l==x then
+					n=inList(m[#m].y+m[#m].l)
+					if n then m[#m].l=m[#m].l+1 end
+				else
+					--TODO: calculate how far ahead we should be from last and current x and y
+					n=inList(m[#m].y+m[#m].l)
+					if n then table.insert(m,{y=b[n],x=x,l=1}) end
 				end
-			end
-		else
-			if #b>0 then
-				local n=#m>0 and inList(m[#m].y+m[#m].l) or 1
-				table.insert(m,{y=b[n],x=x,l=1})
+			else
+				table.insert(m,{y=b[1],x=x,l=1})
 			end
 		end
 	end