1 files changed, 144 insertions, 0 deletions
diff --git a/gfx/skia/skia/include/core/SkMath.h b/gfx/skia/skia/include/core/SkMath.h
new file mode 100644
index 000000000..6e252306d
--- /dev/null
+++ b/gfx/skia/skia/include/core/SkMath.h
@@ -0,0 +1,144 @@
+
+/*
+ * Copyright 2006 The Android Open Source Project
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+
+#ifndef SkMath_DEFINED
+#define SkMath_DEFINED
+
+#include "SkTypes.h"
+
+// 64bit -> 32bit utilities
+
+/**
+ *  Return true iff the 64bit value can exactly be represented in signed 32bits
+ */
+static inline bool sk_64_isS32(int64_t value) {
+    return (int32_t)value == value;
+}
+
+/**
+ *  Return the 64bit argument as signed 32bits, asserting in debug that the arg
+ *  exactly fits in signed 32bits. In the release build, no checks are preformed
+ *  and the return value if the arg does not fit is undefined.
+ */
+static inline int32_t sk_64_asS32(int64_t value) {
+    SkASSERT(sk_64_isS32(value));
+    return (int32_t)value;
+}
+
+// Handy util that can be passed two ints, and will automatically promote to
+// 64bits before the multiply, so the caller doesn't have to remember to cast
+// e.g. (int64_t)a * b;
+static inline int64_t sk_64_mul(int64_t a, int64_t b) {
+    return a * b;
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
+/**
+ *  Computes numer1 * numer2 / denom in full 64 intermediate precision.
+ *  It is an error for denom to be 0. There is no special handling if
+ *  the result overflows 32bits.
+ */
+static inline int32_t SkMulDiv(int32_t numer1, int32_t numer2, int32_t denom) {
+    SkASSERT(denom);
+
+    int64_t tmp = sk_64_mul(numer1, numer2) / denom;
+    return sk_64_asS32(tmp);
+}
+
+/**
+ *  Return the integer square root of value, with a bias of bitBias
+ */
+int32_t SkSqrtBits(int32_t value, int bitBias);
+
+/** Return the integer square root of n, treated as a SkFixed (16.16)
+ */
+#define SkSqrt32(n)         SkSqrtBits(n, 15)
+
+/**
+ *  Returns (value < 0 ? 0 : value) efficiently (i.e. no compares or branches)
+ */
+static inline int SkClampPos(int value) {
+    return value & ~(value >> 31);
+}
+
+/** Given an integer and a positive (max) integer, return the value
+ *  pinned against 0 and max, inclusive.
+ *  @param value    The value we want returned pinned between [0...max]
+ *  @param max      The positive max value
+ *  @return 0 if value < 0, max if value > max, else value
+ */
+static inline int SkClampMax(int value, int max) {
+    // ensure that max is positive
+    SkASSERT(max >= 0);
+    if (value < 0) {
+        value = 0;
+    }
+    if (value > max) {
+        value = max;
+    }
+    return value;
+}
+
+/**
+ *  Returns true if value is a power of 2. Does not explicitly check for
+ *  value <= 0.
+ */
+template <typename T> constexpr inline bool SkIsPow2(T value) {
+    return (value & (value - 1)) == 0;
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
+/**
+ *  Return a*b/((1 << shift) - 1), rounding any fractional bits.
+ *  Only valid if a and b are unsigned and <= 32767 and shift is > 0 and <= 8
+ */
+static inline unsigned SkMul16ShiftRound(U16CPU a, U16CPU b, int shift) {
+    SkASSERT(a <= 32767);
+    SkASSERT(b <= 32767);
+    SkASSERT(shift > 0 && shift <= 8);
+    unsigned prod = a*b + (1 << (shift - 1));
+    return (prod + (prod >> shift)) >> shift;
+}
+
+/**
+ *  Return a*b/255, rounding any fractional bits.
+ *  Only valid if a and b are unsigned and <= 32767.
+ */
+static inline U8CPU SkMulDiv255Round(U16CPU a, U16CPU b) {
+    SkASSERT(a <= 32767);
+    SkASSERT(b <= 32767);
+    unsigned prod = a*b + 128;
+    return (prod + (prod >> 8)) >> 8;
+}
+
+/**
+ * Stores numer/denom and numer%denom into div and mod respectively.
+ */
+template <typename In, typename Out>
+inline void SkTDivMod(In numer, In denom, Out* div, Out* mod) {
+#ifdef SK_CPU_ARM32
+    // If we wrote this as in the else branch, GCC won't fuse the two into one
+    // divmod call, but rather a div call followed by a divmod.  Silly!  This
+    // version is just as fast as calling __aeabi_[u]idivmod manually, but with
+    // prettier code.
+    //
+    // This benches as around 2x faster than the code in the else branch.
+    const In d = numer/denom;
+    *div = static_cast<Out>(d);
+    *mod = static_cast<Out>(numer-d*denom);
+#else
+    // On x86 this will just be a single idiv.
+    *div = static_cast<Out>(numer/denom);
+    *mod = static_cast<Out>(numer%denom);
+#endif
+}
+
+#endif