Use clamp instead of a mix of min and max

Signed-off-by: Abe Wieland <[email protected]>

src/formats/pnm.c

@@ -6,9 +6,10 @@
 
 #include <limits.h>
 
-// Divide a by b, rounding to the nearest integer; evaluates b twice
+// Both assume positive arguments and evaluate b more than once
+// Divide, rounding to nearest (up on ties)
 #define div_near(a, b) (((a) + (b) / 2) / (b))
-// Divide a by b, rounding up; evaluates b twice
+// Divide, rounding up
 #define div_ceil(a, b) (((a) + (b) - 1) / (b))
 
 // PNM file types

src/pixmap.c

@@ -13,6 +13,8 @@
 #include <sys/sysctl.h>
 #endif
 
+#define clamp(a, low, high) (min((high), max((a), (low))))
+
 /** Scale filter parameters. */
 struct scale_param {
     const struct pixmap* src; ///< Source pixmap
@@ -285,11 +287,11 @@ static void scale_bicubic(struct scale_param* sp, size_t start, size_t step)
                     (state[pc][3][0] + state[pc][3][1] * diff_x + state[pc][3][2] * diff_x2 + state[pc][3][3] * diff_x3) * diff_y3;
                 // clang-format on
                 if (pc == 3) {
-                    const uint8_t alpha = max(min(inter, 255), 0);
+                    const uint8_t alpha = clamp(inter, 0, 255);
                     fg |= ARGB_SET_A(alpha);
                 } else {
                     const uint8_t alpha = ARGB_GET_A(fg);
-                    const uint16_t mul = max(min(inter, 255 * alpha), 0);
+                    const uint16_t mul = clamp(inter, 0, 255 * alpha);
                     const uint8_t color = alpha ? mul / alpha : 0;
                     fg |= (color << (pc * 8));
                 }
@@ -523,7 +525,7 @@ void pixmap_scale(enum pixmap_scale scaler, const struct pixmap* src,
 #endif
 
     // background threads
-    const size_t threads_num = min(16, max(cpus, 1)) - 1;
+    const size_t threads_num = clamp(cpus, 1, 16) - 1;
     struct scale_task* tasks = NULL;
 
     // scaling parameters