shithub: libgraphics

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fix a double-free. add a generic value-swapping macro.

--- a/clip.c

+++ b/clip.c

@@ -34,16 +34,6 @@

 }

 static void

-swappoly(Polygon **a, Polygon **b)

-{

-	Polygon *tmp;

-

-	tmp = *a;

-	*a = *b;

-	*b = tmp;

-}

-

-static void

 cleanpoly(Polygon *p)

 {

 	int i;

@@ -128,7 +118,7 @@

 		}

 		cleanpoly(Vin);

 		if(j < 6-1)

-			swappoly(&Vin, &Vout);

+			SWAP(Polygon*, &Vin, &Vout);

 	}

 	if(Vout->n < 2)

@@ -213,8 +203,6 @@

 	perc = len == 0? 0: hypot(Δp.x, Δp.y)/len;

 	lerpvertex(&v[1], v0, v1, perc);

-	delvattrs(v0);

-	delvattrs(v1);

 	*v0 = dupvertex(&v[0]);

 	*v1 = dupvertex(&v[1]);

 }

@@ -244,9 +232,9 @@

 			return -1;

 		if(ptisinside(code0)){

-			swappt(p0, p1);

-			swapi(&code0, &code1);

-			swapvertex(v0, v1);

+			SWAP(Point, p0, p1);

+			SWAP(int, &code0, &code1);

+			SWAP(Vertex, v0, v1);

 		}

 		if(code0 & CLIPL){

--- a/internal.h

+++ b/internal.h

@@ -45,7 +45,6 @@

 /* vertex */

 Vertex dupvertex(Vertex*);

-void swapvertex(Vertex*, Vertex*);

 void lerpvertex(Vertex*, Vertex*, Vertex*, double);

 void berpvertex(Vertex*, Vertex*, Vertex*, Vertex*, Point3);

 void delvattrs(Vertex*);

@@ -58,8 +57,6 @@

 /* util */

 int min(int, int);

 int max(int, int);

-void swapi(int*, int*);

-void swappt(Point*, Point*);

 void memsetf(void*, float, usize);

 void memsetl(void*, ulong, usize);

@@ -70,3 +67,6 @@

 #define getpixel(fb, p) (((fb)->cb)[Dx((fb)->r)*(p).y + (p).x])

 /* void putpixel(Framebuf *fb, Point p, ulong c) */

 #define putpixel(fb, p, c) (((fb)->cb)[Dx((fb)->r)*(p).y + (p).x] = (c))

+

+/* void SWAP(type t, type *a, type *b) */

+#define SWAP(t, a, b) {t tmp; tmp = *(a); *(a) = *(b); *(b) = tmp;}

--- a/render.c

+++ b/render.c

@@ -135,14 +135,14 @@

 		/* transpose the points */

 		if(abs(p0.x-p1.x) < abs(p0.y-p1.y)){

 			steep = 1;

-			swapi(&p0.x, &p0.y);

-			swapi(&p1.x, &p1.y);

+			SWAP(int, &p0.x, &p0.y);

+			SWAP(int, &p1.x, &p1.y);

 		}

 		/* make them left-to-right */

 		if(p0.x > p1.x){

-			swappt(&p0, &p1);

-			swapvertex(&prim.v[0], &prim.v[1]);

+			SWAP(Point, &p0, &p1);

+			SWAP(Vertex, &prim.v[0], &prim.v[1]);

 		}

 		dp = subpt(p1, p0);

@@ -155,7 +155,7 @@

 			dplen = hypot(dp.x, dp.y);

 			perc = dplen == 0? 0: hypot(Δp.x, Δp.y)/dplen;

-			if(steep) swapi(&p.x, &p.y);

+			if(steep) SWAP(int, &p.x, &p.y);

 			z = flerp(prim.v[0].p.z, prim.v[1].p.z, perc);

 			/* TODO get rid of the bounds check and make sure the clipping doesn't overflow */

@@ -176,7 +176,7 @@

 			pixel(params->fb, p, c);

 			delvattrs(&fsp.v);

 discard:

-			if(steep) swapi(&p.x, &p.y);

+			if(steep) SWAP(int, &p.x, &p.y);

 			e += Δe;

 			if(e > dp.x){

--- a/util.c

+++ b/util.c

@@ -32,26 +32,6 @@

 	return a > b? a: b;

 }

-void

-swapi(int *a, int *b)

-{

-	int t;

-

-	t = *a;

-	*a = *b;

-	*b = t;

-}

-

-void

-swappt(Point *a, Point *b)

-{

-	Point t;

-

-	t = *a;

-	*a = *b;

-	*b = t;

-}

-

 Point2

 modulapt2(Point2 a, Point2 b)

 {

--- a/vertex.c

+++ b/vertex.c

@@ -43,16 +43,6 @@

 	return nv;

 }

-void

-swapvertex(Vertex *a, Vertex *b)

-{

-	Vertex t;

-

-	t = *a;

-	*a = *b;

-	*b = t;

-}

-

 /*

  * linear attribute interpolation

  */