| /* |
| * Copyright 2008 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. |
| */ |
| |
| #include "SkMathPriv.h" |
| #include "SkFixed.h" |
| #include "SkFloatBits.h" |
| #include "SkFloatingPoint.h" |
| #include "SkSafeMath.h" |
| #include "SkScalar.h" |
| |
| #define sub_shift(zeros, x, n) \ |
| zeros -= n; \ |
| x >>= n |
| |
| int SkCLZ_portable(uint32_t x) { |
| if (x == 0) { |
| return 32; |
| } |
| |
| int zeros = 31; |
| if (x & 0xFFFF0000) { |
| sub_shift(zeros, x, 16); |
| } |
| if (x & 0xFF00) { |
| sub_shift(zeros, x, 8); |
| } |
| if (x & 0xF0) { |
| sub_shift(zeros, x, 4); |
| } |
| if (x & 0xC) { |
| sub_shift(zeros, x, 2); |
| } |
| if (x & 0x2) { |
| sub_shift(zeros, x, 1); |
| } |
| |
| return zeros; |
| } |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| |
| /* www.worldserver.com/turk/computergraphics/FixedSqrt.pdf |
| */ |
| int32_t SkSqrtBits(int32_t x, int count) { |
| SkASSERT(x >= 0 && count > 0 && (unsigned)count <= 30); |
| |
| uint32_t root = 0; |
| uint32_t remHi = 0; |
| uint32_t remLo = x; |
| |
| do { |
| root <<= 1; |
| |
| remHi = (remHi<<2) | (remLo>>30); |
| remLo <<= 2; |
| |
| uint32_t testDiv = (root << 1) + 1; |
| if (remHi >= testDiv) { |
| remHi -= testDiv; |
| root++; |
| } |
| } while (--count >= 0); |
| |
| return root; |
| } |
| |
| float SkScalarSinCos(float radians, float* cosValue) { |
| float sinValue = sk_float_sin(radians); |
| |
| if (cosValue) { |
| *cosValue = sk_float_cos(radians); |
| if (SkScalarNearlyZero(*cosValue)) { |
| *cosValue = 0; |
| } |
| } |
| |
| if (SkScalarNearlyZero(sinValue)) { |
| sinValue = 0; |
| } |
| return sinValue; |
| } |
| |
| /////////////////////////////////////////////////////////////////////////////////////////////////// |
| |
| size_t SkSafeMath::Add(size_t x, size_t y) { |
| SkSafeMath tmp; |
| size_t sum = tmp.add(x, y); |
| return tmp.ok() ? sum : SK_MaxSizeT; |
| } |
| |
| size_t SkSafeMath::Mul(size_t x, size_t y) { |
| SkSafeMath tmp; |
| size_t prod = tmp.mul(x, y); |
| return tmp.ok() ? prod : SK_MaxSizeT; |
| } |