Privatization:

move SkFDot.h to private
move parts of SkMath.h into SkMathPriv.h
Review URL: https://codereview.appspot.com/6461045

git-svn-id: http://skia.googlecode.com/svn/trunk@4997 2bbb7eff-a529-9590-31e7-b0007b416f81

2 files changed, 63 insertions, 191 deletions

diff --git a/include/core/SkFDot6.h b/include/core/SkFDot6.h
deleted file mode 100644
index aa588572f8..0000000000
--- a/include/core/SkFDot6.h
+++ /dev/null
@@ -1,58 +0,0 @@
-
-/*
- * 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 SkFDot6_DEFINED
-#define SkFDot6_DEFINED
-
-#include "SkMath.h"
-
-typedef int32_t SkFDot6;
-
-#define SK_FDot6One         (64)
-#define SK_FDot6Half        (32)
-
-#ifdef SK_DEBUG
-    inline SkFDot6 SkIntToFDot6(S16CPU x) {
-        SkASSERT(SkToS16(x) == x);
-        return x << 6;
-    }
-#else
-    #define SkIntToFDot6(x) ((x) << 6)
-#endif
-
-#define SkFDot6Floor(x)     ((x) >> 6)
-#define SkFDot6Ceil(x)      (((x) + 63) >> 6)
-#define SkFDot6Round(x)     (((x) + 32) >> 6)
-
-#define SkFixedToFDot6(x)   ((x) >> 10)
-
-inline SkFixed SkFDot6ToFixed(SkFDot6 x) {
-    SkASSERT((x << 10 >> 10) == x);
-
-    return x << 10;
-}
-
-#ifdef SK_SCALAR_IS_FLOAT
-    #define SkScalarToFDot6(x)  (SkFDot6)((x) * 64)
-#else
-    #define SkScalarToFDot6(x)  ((x) >> 10)
-#endif
-
-inline SkFixed SkFDot6Div(SkFDot6 a, SkFDot6 b) {
-    SkASSERT(b != 0);
-
-    if (a == (int16_t)a) {
-        return (a << 16) / b;
-    } else {
-        return SkFixedDiv(a, b);
-    }
-}
-
-#endif
-
diff --git a/include/core/SkMath.h b/include/core/SkMath.h
index 7a4b707ce7..42f830cf2f 100644
--- a/include/core/SkMath.h
+++ b/include/core/SkMath.h
@@ -12,68 +12,51 @@
 
 #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.
-*/
+/**
+ *  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.
-*/
+/**
+ *  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
-*/
+/**
+ *  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 the number of leading zero bits (0...32)
+int SkCLZ_portable(uint32_t);
 
-/** Return x with the sign of y */
-static inline int32_t SkCopySign32(int32_t x, int32_t y) {
-    return SkApplySign(x, SkExtractSign(x ^ y));
-}
+#if defined(__arm__)
+    #define SkCLZ(x)    __builtin_clz(x)
+#endif
+
+#ifndef SkCLZ
+    #define SkCLZ(x)    SkCLZ_portable(x)
+#endif
 
-/** Returns (value < 0 ? 0 : value) efficiently (i.e. no compares or branches)
-*/
+/**
+ *  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
-*/
+ *  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);
@@ -86,62 +69,33 @@ static inline int SkClampMax(int value, int max) {
     return value;
 }
 
-/** 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__)
-    #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.
-*/
+/**
+ *  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
-*/
+/**
+ *  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.
+/**
+ *  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;
@@ -149,10 +103,11 @@ static inline bool SkIsPow2(int value) {
 
 ///////////////////////////////////////////////////////////////////////////////
 
-/** 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.
-*/
+/**
+ *  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);
@@ -176,39 +131,10 @@ static inline bool SkIsPow2(int value) {
     #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
+/**
+ *  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 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)/255, taking the ceiling of any fractional bits. Only valid if
-    both a and b are 0..255. The expected result equals (a * b + 254) / 255.
- */
-static inline U8CPU SkMulDiv255Ceiling(U8CPU a, U8CPU b) {
-    SkASSERT((uint8_t)a == a);
-    SkASSERT((uint8_t)b == b);
-    unsigned prod = SkMulS16(a, b) + 255;
-    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);
@@ -217,10 +143,14 @@ static inline unsigned SkMul16ShiftRound(unsigned a, unsigned b, int shift) {
     return (prod + (prod >> shift)) >> shift;
 }
 
-/** Just the rounding step in SkDiv255Round: round(value / 255)
+/**
+ *  Return a*b/255, rounding any fractional bits. Only valid if both
+ *  a and b are 0..255
  */
-static inline unsigned SkDiv255Round(unsigned prod) {
-    prod += 128;
+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;
 }