Commit de3b5c201ca52e6558c21b09012d9faa1bfd1722
2021-08-20T13:51:40
[smooth] Fortify 64-bit algorithm. * src/smooth/ftgrays.c (FT_UDIVPREP, FT_UDIV): s/long/FT_Int64/ and s/unsigned long/FT_UInt64/. (gray_render_line): Adjust a critical variable type.
diff --git a/src/smooth/ftgrays.c b/src/smooth/ftgrays.c
index 0ae187f..d433e09 100644
--- a/src/smooth/ftgrays.c
+++ b/src/smooth/ftgrays.c
@@ -375,12 +375,12 @@ typedef ptrdiff_t FT_PtrDist;
/* These macros speed up repetitive divisions by replacing them */
/* with multiplications and right shifts. */
-#define FT_UDIVPREP( c, b ) \
- long b ## _r = c ? (long)( FT_ULONG_MAX >> PIXEL_BITS ) / ( b ) \
+#define FT_UDIVPREP( c, b ) \
+ FT_Int64 b ## _r = c ? (FT_Int64)( ~(FT_UInt64)0 >> PIXEL_BITS ) / ( b ) \
: 0
-#define FT_UDIV( a, b ) \
- (TCoord)( ( (unsigned long)( a ) * (unsigned long)( b ## _r ) ) >> \
- ( sizeof( long ) * FT_CHAR_BIT - PIXEL_BITS ) )
+#define FT_UDIV( a, b ) \
+ (TCoord)( ( (FT_UInt64)( a ) * (FT_UInt64)( b ## _r ) ) >> \
+ ( sizeof( FT_UInt64 ) * FT_CHAR_BIT - PIXEL_BITS ) )
/* Scale area and apply fill rule to calculate the coverage byte. */
@@ -921,7 +921,7 @@ typedef ptrdiff_t FT_PtrDist;
}
else /* any other line */
{
- TPos prod = dx * (TPos)fy1 - dy * (TPos)fx1;
+ FT_Int64 prod = dx * (FT_Int64)fy1 - dy * (FT_Int64)fx1;
FT_UDIVPREP( ex1 != ex2, dx );
FT_UDIVPREP( ey1 != ey2, dy );