add saturate helper for float2int64

Bug: skia:
Change-Id: I157f8c047145874c4585ae870018163908389b26
Reviewed-on: https://skia-review.googlesource.com/102321
Reviewed-by: Mike Klein <mtklein@google.com>
Reviewed-by: Florin Malita <fmalita@chromium.org>

4 files changed, 40 insertions, 4 deletions

diff --git a/include/core/SkTypes.h b/include/core/SkTypes.h
index 50efbaea0e..afab728666 100644
--- a/include/core/SkTypes.h
+++ b/include/core/SkTypes.h
@@ -212,6 +212,8 @@ template <typename D, typename S> constexpr D SkTo(S s) {
 #define SK_MinU32   0
 #define SK_NaN32    ((int) (1U << 31))
 #define SK_MaxSizeT SIZE_MAX
+static constexpr int64_t SK_MaxS64 = 0x7FFFFFFFFFFFFFFF;
+static constexpr int64_t SK_MinS64 = -SK_MaxS64;
 
 static inline int32_t SkLeftShift(int32_t value, int32_t shift) {
     return (int32_t) ((uint32_t) value << shift);
diff --git a/include/private/SkFixed.h b/include/private/SkFixed.h
index 05e1de49c9..75514d8f1e 100644
--- a/include/private/SkFixed.h
+++ b/include/private/SkFixed.h
@@ -124,14 +124,14 @@ static inline SkFixed SkFixedMul(SkFixed a, SkFixed b) {
 
 typedef int64_t SkFixed3232;   // 32.32
 
-#define SkFixed3232Max            (0x7FFFFFFFFFFFFFFFLL)
+#define SkFixed3232Max            SK_MaxS64
 #define SkFixed3232Min            (-SkFixed3232Max)
 
 #define SkIntToFixed3232(x)       (SkLeftShift((SkFixed3232)(x), 32))
 #define SkFixed3232ToInt(x)       ((int)((x) >> 32))
 #define SkFixedToFixed3232(x)     (SkLeftShift((SkFixed3232)(x), 16))
 #define SkFixed3232ToFixed(x)     ((SkFixed)((x) >> 16))
-#define SkFloatToFixed3232(x)     ((SkFixed3232)((x) * (65536.0f * 65536.0f)))
+#define SkFloatToFixed3232(x)     sk_float_saturate2int64((x) * (65536.0f * 65536.0f))
 #define SkFixed3232ToFloat(x)     (x * (1 / (65536.0f * 65536.0f)))
 
 #define SkScalarToFixed3232(x)    SkFloatToFixed3232(x)
diff --git a/include/private/SkFloatingPoint.h b/include/private/SkFloatingPoint.h
index 05191e651d..bbb117982f 100644
--- a/include/private/SkFloatingPoint.h
+++ b/include/private/SkFloatingPoint.h
@@ -81,6 +81,9 @@ static inline float sk_float_pow(float base, float exp) {
 #define SK_MaxS32FitsInFloat    2147483520
 #define SK_MinS32FitsInFloat    -SK_MaxS32FitsInFloat
 
+#define SK_MaxS64FitsInFloat    (SK_MaxS64 >> (63-24) << (63-24))   // 0x7fffff8000000000
+#define SK_MinS64FitsInFloat    -SK_MaxS64FitsInFloat
+
 /**
  *  Return the closest int for the given float. Returns SK_MaxS32FitsInFloat for NaN.
  */
@@ -99,6 +102,15 @@ static inline int sk_double_saturate2int(double x) {
     return (int)x;
 }
 
+/**
+ *  Return the closest int64_t for the given float. Returns SK_MaxS64FitsInFloat for NaN.
+ */
+static inline int64_t sk_float_saturate2int64(float x) {
+    x = SkTMin<float>(x, SK_MaxS64FitsInFloat);
+    x = SkTMax<float>(x, SK_MinS64FitsInFloat);
+    return (int64_t)x;
+}
+
 #define sk_float_floor2int(x)   sk_float_saturate2int(sk_float_floor(x))
 #define sk_float_round2int(x)   sk_float_saturate2int(sk_float_floor((x) + 0.5f))
 #define sk_float_ceil2int(x)    sk_float_saturate2int(sk_float_ceil(x))
diff --git a/tests/MathTest.cpp b/tests/MathTest.cpp
index 0d0bdce67d..31bb45308c 100644
--- a/tests/MathTest.cpp
+++ b/tests/MathTest.cpp
@@ -672,7 +672,7 @@ DEF_TEST(GrNextSizePow2, reporter) {
     test_nextsizepow2(reporter, SIZE_MAX, SIZE_MAX);
 }
 
-DEF_TEST(FloatSaturate, reporter) {
+DEF_TEST(FloatSaturate32, reporter) {
     const struct {
         float   fFloat;
         int     fExpectedInt;
@@ -694,7 +694,29 @@ DEF_TEST(FloatSaturate, reporter) {
     }
 }
 
-DEF_TEST(DoubleSaturate, reporter) {
+DEF_TEST(FloatSaturate64, reporter) {
+    const struct {
+        float   fFloat;
+        int64_t fExpected64;
+    } recs[] = {
+        { 0, 0 },
+        { 100.5f, 100 },
+        { (float)SK_MaxS64, SK_MaxS64FitsInFloat },
+        { (float)SK_MinS64, SK_MinS64FitsInFloat },
+        { SK_MaxS64 * 100.0f, SK_MaxS64FitsInFloat },
+        { SK_MinS64 * 100.0f, SK_MinS64FitsInFloat },
+        { SK_ScalarInfinity, SK_MaxS64FitsInFloat },
+        { SK_ScalarNegativeInfinity, SK_MinS64FitsInFloat },
+        { SK_ScalarNaN, SK_MaxS64FitsInFloat },
+    };
+
+    for (auto r : recs) {
+        int64_t i = sk_float_saturate2int64(r.fFloat);
+        REPORTER_ASSERT(reporter, r.fExpected64 == i);
+    }
+}
+
+DEF_TEST(DoubleSaturate32, reporter) {
     const struct {
         double  fDouble;
         int     fExpectedInt;