The Tor Browser: gfx/skia/trunk/include/core/SkMath.h@129ffea94266 (annotated)

gfx/skia/trunk/include/core/SkMath.h@129ffea94266 (annotated)

gfx/skia/trunk/include/core/SkMath.h

Sat, 03 Jan 2015 20:18:00 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Sat, 03 Jan 2015 20:18:00 +0100
branch: TOR_BUG_3246
changeset 7: 129ffea94266
permissions: -rw-r--r--

Conditionally enable double key logic according to:
private browsing mode or privacy.thirdparty.isolate preference and
implement in GetCookieStringCommon and FindCookie where it counts...
With some reservations of how to convince FindCookie users to test
condition and pass a nullptr when disabling double key logic.

 /*
  * 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"
 /**
  *  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)
 // 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;
 }
 ///////////////////////////////////////////////////////////////////////////////
 //! Returns the number of leading zero bits (0...32)
 int SkCLZ_portable(uint32_t);
 #ifndef SkCLZ
     #if defined(_MSC_VER) && _MSC_VER >= 1400
         #include <intrin.h>
         static inline int SkCLZ(uint32_t mask) {
             if (mask) {
                 DWORD index;
                 _BitScanReverse(&index, mask);
                 return index ^ 0x1F;
             } else {
                 return 32;
             }
         }
     #elif defined(SK_CPU_ARM) || defined(__GNUC__) || defined(__clang__)
         static inline int SkCLZ(uint32_t mask) {
             // __builtin_clz(0) is undefined, so we have to detect that case.
             return mask ? __builtin_clz(mask) : 32;
         }
     #else
         #define SkCLZ(x)    SkCLZ_portable(x)
     #endif
 #endif
 /**
  *  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 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);
 }
 /**
  *  Returns true if value is a power of 2. Does not explicitly check for
  *  value <= 0.
  */
 static inline bool SkIsPow2(int value) {
     return (value & (value - 1)) == 0;
 }
 ///////////////////////////////////////////////////////////////////////////////
 /**
  *  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.
  */
 #ifdef SK_ARM_HAS_EDSP
     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/((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 = SkMulS16(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 = SkMulS16(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_ARM
     // 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  // SK_CPU_ARM
 }
 #endif

The Tor Browser / annotate

gfx/skia/trunk/include/core/SkMath.h@129ffea94266 (annotated)

gfx/skia/trunk/include/core/SkMath.h