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author | The Android Open Source Project <initial-contribution@android.com> | 2009-03-03 18:28:36 -0800 |
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committer | The Android Open Source Project <initial-contribution@android.com> | 2009-03-03 18:28:36 -0800 |
commit | 6eb364108744656fcd23a96a478aa772cd4e85bc (patch) | |
tree | 4b825dc642cb6eb9a060e54bf8d69288fbee4904 /include/core/SkMath.h | |
parent | a23c4e24d873b11674987f97f1946e1c4d97e782 (diff) | |
download | external_skia-6eb364108744656fcd23a96a478aa772cd4e85bc.zip external_skia-6eb364108744656fcd23a96a478aa772cd4e85bc.tar.gz external_skia-6eb364108744656fcd23a96a478aa772cd4e85bc.tar.bz2 |
auto import from //depot/cupcake/@135843
Diffstat (limited to 'include/core/SkMath.h')
-rw-r--r-- | include/core/SkMath.h | 230 |
1 files changed, 0 insertions, 230 deletions
diff --git a/include/core/SkMath.h b/include/core/SkMath.h deleted file mode 100644 index 5c2b475..0000000 --- a/include/core/SkMath.h +++ /dev/null @@ -1,230 +0,0 @@ -/* - * Copyright (C) 2006 The Android Open Source Project - * - * Licensed under the Apache License, Version 2.0 (the "License"); - * you may not use this file except in compliance with the License. - * You may obtain a copy of the License at - * - * http://www.apache.org/licenses/LICENSE-2.0 - * - * Unless required by applicable law or agreed to in writing, software - * distributed under the License is distributed on an "AS IS" BASIS, - * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. - * See the License for the specific language governing permissions and - * limitations under the License. - */ - -#ifndef SkMath_DEFINED -#define SkMath_DEFINED - -#include "SkTypes.h" - -//! Returns the number of leading zero bits (0...32) -int SkCLZ_portable(uint32_t); - -/** Computes the 64bit product of a * b, and then shifts the answer down by - shift bits, returning the low 32bits. shift must be [0..63] - e.g. to perform a fixedmul, call SkMulShift(a, b, 16) -*/ -int32_t SkMulShift(int32_t a, int32_t b, unsigned shift); - -/** 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. -*/ -int32_t SkMulDiv(int32_t numer1, int32_t numer2, int32_t denom); - -/** Computes (numer1 << shift) / 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. -*/ -int32_t SkDivBits(int32_t numer, int32_t denom, int shift); - -/** 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) - -/** Return the integer cube root of value, with a bias of bitBias - */ -int32_t SkCubeRootBits(int32_t value, int bitBias); - -/** Returns -1 if n < 0, else returns 0 -*/ -#define SkExtractSign(n) ((int32_t)(n) >> 31) - -/** If sign == -1, returns -n, else sign must be 0, and returns n. - Typically used in conjunction with SkExtractSign(). -*/ -static inline int32_t SkApplySign(int32_t n, int32_t sign) { - SkASSERT(sign == 0 || sign == -1); - return (n ^ sign) - sign; -} - -/** 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. - Note: only works as long as max - value doesn't wrap around - @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); - // ensure that if value is negative, max - value doesn't wrap around - SkASSERT(value >= 0 || max - value > 0); - -#ifdef SK_CPU_HAS_CONDITIONAL_INSTR - if (value < 0) { - value = 0; - } - if (value > max) { - value = max; - } - return value; -#else - - int diff = max - value; - // clear diff if diff is positive - diff &= diff >> 31; - - // clear the result if value < 0 - return (value + diff) & ~(value >> 31); -#endif -} - -/** Given a positive value and a positive max, return the value - pinned against max. - Note: only works as long as max - value doesn't wrap around - @return max if value >= max, else value -*/ -static inline unsigned SkClampUMax(unsigned value, unsigned max) { -#ifdef SK_CPU_HAS_CONDITIONAL_INSTR - if (value > max) { - value = max; - } - return value; -#else - int diff = max - value; - // clear diff if diff is positive - diff &= diff >> 31; - - return value + diff; -#endif -} - -/////////////////////////////////////////////////////////////////////////////// - -#if defined(__arm__) && !defined(__thumb__) - #define SkCLZ(x) __builtin_clz(x) -#endif - -#ifndef SkCLZ - #define SkCLZ(x) SkCLZ_portable(x) -#endif - -/////////////////////////////////////////////////////////////////////////////// - -/** Returns the smallest power-of-2 that is >= the specified value. If value - is already a power of 2, then it is returned unchanged. It is undefined - if value is <= 0. -*/ -static inline int SkNextPow2(int value) { - SkASSERT(value > 0); - return 1 << (32 - SkCLZ(value - 1)); -} - -/** Returns the log2 of the specified value, were that value to be rounded up - to the next power of 2. It is undefined to pass 0. Examples: - SkNextLog2(1) -> 0 - SkNextLog2(2) -> 1 - SkNextLog2(3) -> 2 - SkNextLog2(4) -> 2 - SkNextLog2(5) -> 3 -*/ -static inline int SkNextLog2(uint32_t value) { - SkASSERT(value != 0); - return 32 - SkCLZ(value - 1); -} - -/////////////////////////////////////////////////////////////////////////////// - -/** SkMulS16(a, b) multiplies a * b, but requires that a and b are both int16_t. - With this requirement, we can generate faster instructions on some - architectures. -*/ -#if defined(__arm__) && !defined(__thumb__) - static inline int32_t SkMulS16(S16CPU x, S16CPU y) { - SkASSERT((int16_t)x == x); - SkASSERT((int16_t)y == y); - int32_t product; - asm("smulbb %0, %1, %2 \n" - : "=r"(product) - : "r"(x), "r"(y) - : - ); - return product; - } -#else - #ifdef SK_DEBUG - static inline int32_t SkMulS16(S16CPU x, S16CPU y) { - SkASSERT((int16_t)x == x); - SkASSERT((int16_t)y == y); - return x * y; - } - #else - #define SkMulS16(x, y) ((x) * (y)) - #endif -#endif - -/** Return a*b/255, truncating away any fractional bits. Only valid if both - a and b are 0..255 -*/ -static inline U8CPU SkMulDiv255Trunc(U8CPU a, U8CPU b) { - SkASSERT((uint8_t)a == a); - SkASSERT((uint8_t)b == b); - unsigned prod = SkMulS16(a, b) + 1; - return (prod + (prod >> 8)) >> 8; -} - -/** Return a*b/255, rounding any fractional bits. Only valid if both - a and b are 0..255 - */ -static inline U8CPU SkMulDiv255Round(U8CPU a, U8CPU b) { - SkASSERT((uint8_t)a == a); - SkASSERT((uint8_t)b == b); - unsigned prod = SkMulS16(a, b) + 128; - return (prod + (prod >> 8)) >> 8; -} - -/** 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(unsigned a, unsigned b, int shift) { - SkASSERT(a <= 32767); - SkASSERT(b <= 32767); - SkASSERT(shift > 0 && shift <= 8); - unsigned prod = SkMulS16(a, b) + (1 << (shift - 1)); - return (prod + (prod >> shift)) >> shift; -} - -/////////////////////////////////////////////////////////////////////////////// - -#ifdef SK_DEBUG - class SkMath { - public: - static void UnitTest(); - }; -#endif - -#endif - |