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 /* * 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. */ #ifndef SkFloatBits_DEFINED #define SkFloatBits_DEFINED #include "SkTypes.h" /** Convert a sign-bit int (i.e. float interpreted as int) into a 2s compliement int. This also converts -0 (0x80000000) to 0. Doing this to a float allows it to be compared using normal C operators (<, <=, etc.) */ static inline int32_t SkSignBitTo2sCompliment(int32_t x) { if (x < 0) { x &= 0x7FFFFFFF; x = -x; } return x; } /** Convert a 2s compliment int to a sign-bit (i.e. int interpreted as float). This undoes the result of SkSignBitTo2sCompliment(). */ static inline int32_t Sk2sComplimentToSignBit(int32_t x) { int sign = x >> 31; // make x positive x = (x ^ sign) - sign; // set the sign bit as needed x |= sign << 31; return x; } /** Given the bit representation of a float, return its value cast to an int. If the value is out of range, or NaN, return return +/- SK_MaxS32 */ int32_t SkFloatBits_toIntCast(int32_t floatBits); /** Given the bit representation of a float, return its floor as an int. If the value is out of range, or NaN, return return +/- SK_MaxS32 */ SK_API int32_t SkFloatBits_toIntFloor(int32_t floatBits); /** Given the bit representation of a float, return it rounded to an int. If the value is out of range, or NaN, return return +/- SK_MaxS32 */ SK_API int32_t SkFloatBits_toIntRound(int32_t floatBits); /** Given the bit representation of a float, return its ceiling as an int. If the value is out of range, or NaN, return return +/- SK_MaxS32 */ SK_API int32_t SkFloatBits_toIntCeil(int32_t floatBits); union SkFloatIntUnion { float fFloat; int32_t fSignBitInt; }; // Helper to see a float as its bit pattern (w/o aliasing warnings) static inline int32_t SkFloat2Bits(float x) { SkFloatIntUnion data; data.fFloat = x; return data.fSignBitInt; } // Helper to see a bit pattern as a float (w/o aliasing warnings) static inline float SkBits2Float(int32_t floatAsBits) { SkFloatIntUnion data; data.fSignBitInt = floatAsBits; return data.fFloat; } /** Return the float as a 2s compliment int. Just to be used to compare floats to each other or against positive float-bit-constants (like 0). This does not return the int equivalent of the float, just something cheaper for compares-only. */ static inline int32_t SkFloatAs2sCompliment(float x) { return SkSignBitTo2sCompliment(SkFloat2Bits(x)); } /** Return the 2s compliment int as a float. This undos the result of SkFloatAs2sCompliment */ static inline float Sk2sComplimentAsFloat(int32_t x) { return SkBits2Float(Sk2sComplimentToSignBit(x)); } /** Return x cast to a float (i.e. (float)x) */ float SkIntToFloatCast(int x); float SkIntToFloatCast_NoOverflowCheck(int x); /** Return the float cast to an int. If the value is out of range, or NaN, return +/- SK_MaxS32 */ static inline int32_t SkFloatToIntCast(float x) { return SkFloatBits_toIntCast(SkFloat2Bits(x)); } /** Return the floor of the float as an int. If the value is out of range, or NaN, return +/- SK_MaxS32 */ static inline int32_t SkFloatToIntFloor(float x) { return SkFloatBits_toIntFloor(SkFloat2Bits(x)); } /** Return the float rounded to an int. If the value is out of range, or NaN, return +/- SK_MaxS32 */ static inline int32_t SkFloatToIntRound(float x) { return SkFloatBits_toIntRound(SkFloat2Bits(x)); } /** Return the ceiling of the float as an int. If the value is out of range, or NaN, return +/- SK_MaxS32 */ static inline int32_t SkFloatToIntCeil(float x) { return SkFloatBits_toIntCeil(SkFloat2Bits(x)); } // Scalar wrappers for float-bit routines #define SkScalarAs2sCompliment(x) SkFloatAs2sCompliment(x) #define Sk2sComplimentAsScalar(x) Sk2sComplimentAsFloat(x) #endif