[Git][freetype/freetype][master] * src/base/ftobjs.c (FT_Request_Metrics): Avoid division by zero.

[Alexei Podtelezhnikov (@apodtele)]

Alexei Podtelezhnikov pushed to branch master at FreeType / FreeType

Commits:

• 81a456b2
  by Alexei Podtelezhnikov at 2023-01-04T22:41:34-05:00

  * src/base/ftobjs.c (FT_Request_Metrics): Avoid division by zero.
  
  The division-by-zero might happen in broken fonts (see #1194).
  Instead of returning a huge number from FT_DivFix and failing
  to scale later, we now bail immediately.
  

1 changed file:

• src/base/ftobjs.c

Changes:

src/base/ftobjs.c

---

...	...	@@ -3280,34 +3280,49 @@
3280	3280	scaled_h = FT_REQUEST_HEIGHT( req );
3281	3281
3282	3282	/* determine scales */
3283		- if ( req->width )
	3283	+ if ( req->height || !req->width )
3284	3284	{
3285		- metrics->x_scale = FT_DivFix( scaled_w, w );
3286		-
3287		- if ( req->height )
	3285	+ if ( h == 0 )
3288	3286	{
3289		- metrics->y_scale = FT_DivFix( scaled_h, h );
3290		-
3291		- if ( req->type == FT_SIZE_REQUEST_TYPE_CELL )
3292		- {
3293		- if ( metrics->y_scale > metrics->x_scale )
3294		- metrics->y_scale = metrics->x_scale;
3295		- else
3296		- metrics->x_scale = metrics->y_scale;
3297		- }
	3287	+ FT_ERROR(( "FT_Request_Metrics: Divide by zero\n" ));
	3288	+ error = FT_ERR( Divide_By_Zero );
	3289	+ goto Exit;
3298	3290	}
3299		- else
	3291	+
	3292	+ metrics->y_scale = FT_DivFix( scaled_h, h );
	3293	+ }
	3294	+
	3295	+ if ( req->width )
	3296	+ {
	3297	+ if ( w == 0 )
3300	3298	{
3301		- metrics->y_scale = metrics->x_scale;
3302		- scaled_h = FT_MulDiv( scaled_w, h, w );
	3299	+ FT_ERROR(( "FT_Request_Metrics: Divide by zero\n" ));
	3300	+ error = FT_ERR( Divide_By_Zero );
	3301	+ goto Exit;
3303	3302	}
	3303	+
	3304	+ metrics->x_scale = FT_DivFix( scaled_w, w );
3304	3305	}
3305	3306	else
3306	3307	{
3307		- metrics->x_scale = metrics->y_scale = FT_DivFix( scaled_h, h );
	3308	+ metrics->x_scale = metrics->y_scale;
3308	3309	scaled_w = FT_MulDiv( scaled_h, w, h );
3309	3310	}
3310	3311
	3312	+ if ( !req->height )
	3313	+ {
	3314	+ metrics->y_scale = metrics->x_scale;
	3315	+ scaled_h = FT_MulDiv( scaled_w, h, w );
	3316	+ }
	3317	+
	3318	+ if ( req->type == FT_SIZE_REQUEST_TYPE_CELL )
	3319	+ {
	3320	+ if ( metrics->y_scale > metrics->x_scale )
	3321	+ metrics->y_scale = metrics->x_scale;
	3322	+ else
	3323	+ metrics->x_scale = metrics->y_scale;
	3324	+ }
	3325	+
3311	3326	Calculate_Ppem:
3312	3327	/* calculate the ppems */
3313	3328	if ( req->type != FT_SIZE_REQUEST_TYPE_NOMINAL )

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