more shuffling

1 files changed, 29 insertions, 0 deletions

diff --git a/include/fitz/base_math.h b/include/fitz/base_math.h
new file mode 100644
index 00000000..4dee81fc
--- /dev/null
+++ b/include/fitz/base_math.h
@@ -0,0 +1,29 @@
+/* multiply 8-bit fixpoint (0..1) so that 0*0==0 and 255*255==255 */
+#define fz_mul255(a,b) (((a) * ((b) + 1)) >> 8)
+#define fz_floor(x) floor(x)
+#define fz_ceil(x) ceil(x)
+
+/* divide and floor towards -inf */
+static inline int fz_idiv(int a, int b)
+{
+	return a < 0 ? (a - b + 1) / b : a / b;
+}
+
+/* from python */
+static inline void fz_idivmod(int x, int y, int *d, int *m)
+{
+	int xdivy = x / y;
+	int xmody = x - xdivy * y;
+	/* If the signs of x and y differ, and the remainder is non-0,
+	 * C89 doesn't define whether xdivy is now the floor or the
+	 * ceiling of the infinitely precise quotient.  We want the floor,
+	 * and we have it iff the remainder's sign matches y's.
+	 */
+	if (xmody && ((y ^ xmody) < 0)) {
+		xmody += y;
+		xdivy --;
+	}
+	*d = xdivy;
+	*m = xmody;
+}
+