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/*
File: CABitOperations.h
Abstract: Part of CoreAudio Utility Classes
Version: 1.1
Disclaimer: IMPORTANT: This Apple software is supplied to you by Apple
Inc. ("Apple") in consideration of your agreement to the following
terms, and your use, installation, modification or redistribution of
this Apple software constitutes acceptance of these terms. If you do
not agree with these terms, please do not use, install, modify or
redistribute this Apple software.
In consideration of your agreement to abide by the following terms, and
subject to these terms, Apple grants you a personal, non-exclusive
license, under Apple's copyrights in this original Apple software (the
"Apple Software"), to use, reproduce, modify and redistribute the Apple
Software, with or without modifications, in source and/or binary forms;
provided that if you redistribute the Apple Software in its entirety and
without modifications, you must retain this notice and the following
text and disclaimers in all such redistributions of the Apple Software.
Neither the name, trademarks, service marks or logos of Apple Inc. may
be used to endorse or promote products derived from the Apple Software
without specific prior written permission from Apple. Except as
expressly stated in this notice, no other rights or licenses, express or
implied, are granted by Apple herein, including but not limited to any
patent rights that may be infringed by your derivative works or by other
works in which the Apple Software may be incorporated.
The Apple Software is provided by Apple on an "AS IS" basis. APPLE
MAKES NO WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION
THE IMPLIED WARRANTIES OF NON-INFRINGEMENT, MERCHANTABILITY AND FITNESS
FOR A PARTICULAR PURPOSE, REGARDING THE APPLE SOFTWARE OR ITS USE AND
OPERATION ALONE OR IN COMBINATION WITH YOUR PRODUCTS.
IN NO EVENT SHALL APPLE BE LIABLE FOR ANY SPECIAL, INDIRECT, INCIDENTAL
OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
INTERRUPTION) ARISING IN ANY WAY OUT OF THE USE, REPRODUCTION,
MODIFICATION AND/OR DISTRIBUTION OF THE APPLE SOFTWARE, HOWEVER CAUSED
AND WHETHER UNDER THEORY OF CONTRACT, TORT (INCLUDING NEGLIGENCE),
STRICT LIABILITY OR OTHERWISE, EVEN IF APPLE HAS BEEN ADVISED OF THE
POSSIBILITY OF SUCH DAMAGE.
Copyright (C) 2014 Apple Inc. All Rights Reserved.
*/
#ifndef _CABitOperations_h_
#define _CABitOperations_h_
#if !defined(__COREAUDIO_USE_FLAT_INCLUDES__)
//#include <CoreServices/../Frameworks/CarbonCore.framework/Headers/MacTypes.h>
#include <CoreFoundation/CFBase.h>
#else
// #include <MacTypes.h>
#include "CFBase.h"
#endif
#include <TargetConditionals.h>
// return whether a number is a power of two
inline UInt32 IsPowerOfTwo(UInt32 x)
{
return (x & (x-1)) == 0;
}
// count the leading zeros in a word
// Metrowerks Codewarrior. powerpc native count leading zeros instruction:
// I think it's safe to remove this ...
//#define CountLeadingZeroes(x) ((int)__cntlzw((unsigned int)x))
inline UInt32 CountLeadingZeroes(UInt32 arg)
{
// GNUC / LLVM have a builtin
#if defined(__GNUC__) || defined(__llvm___)
#if (TARGET_CPU_X86 || TARGET_CPU_X86_64)
if (arg == 0) return 32;
#endif // TARGET_CPU_X86 || TARGET_CPU_X86_64
return __builtin_clz(arg);
#elif TARGET_OS_WIN32
UInt32 tmp;
__asm{
bsr eax, arg
mov ecx, 63
cmovz eax, ecx
xor eax, 31
mov tmp, eax // this moves the result in tmp to return.
}
return tmp;
#else
#error "Unsupported architecture"
#endif // defined(__GNUC__)
}
// Alias (with different spelling)
#define CountLeadingZeros CountLeadingZeroes
inline UInt32 CountLeadingZeroesLong(UInt64 arg)
{
// GNUC / LLVM have a builtin
#if defined(__GNUC__) || defined(__llvm___)
#if (TARGET_CPU_X86 || TARGET_CPU_X86_64)
if (arg == 0) return 64;
#endif // TARGET_CPU_X86 || TARGET_CPU_X86_64
return __builtin_clzll(arg);
#elif TARGET_OS_WIN32
UInt32 x = CountLeadingZeroes((UInt32)(arg >> 32));
if(x < 32)
return x;
else
return 32+CountLeadingZeroes((UInt32)arg);
#else
#error "Unsupported architecture"
#endif // defined(__GNUC__)
}
#define CountLeadingZerosLong CountLeadingZeroesLong
// count trailing zeroes
inline UInt32 CountTrailingZeroes(UInt32 x)
{
return 32 - CountLeadingZeroes(~x & (x-1));
}
// count leading ones
inline UInt32 CountLeadingOnes(UInt32 x)
{
return CountLeadingZeroes(~x);
}
// count trailing ones
inline UInt32 CountTrailingOnes(UInt32 x)
{
return 32 - CountLeadingZeroes(x & (~x-1));
}
// number of bits required to represent x.
inline UInt32 NumBits(UInt32 x)
{
return 32 - CountLeadingZeroes(x);
}
// base 2 log of next power of two greater or equal to x
inline UInt32 Log2Ceil(UInt32 x)
{
return 32 - CountLeadingZeroes(x - 1);
}
// base 2 log of next power of two less or equal to x
inline UInt32 Log2Floor(UInt32 x)
{
return 32 - CountLeadingZeroes(x) - 1;
}
// next power of two greater or equal to x
inline UInt32 NextPowerOfTwo(UInt32 x)
{
return 1 << Log2Ceil(x);
}
// counting the one bits in a word
inline UInt32 CountOnes(UInt32 x)
{
// secret magic algorithm for counting bits in a word.
x = x - ((x >> 1) & 0x55555555);
x = (x & 0x33333333) + ((x >> 2) & 0x33333333);
return (((x + (x >> 4)) & 0x0F0F0F0F) * 0x01010101) >> 24;
}
// counting the zero bits in a word
inline UInt32 CountZeroes(UInt32 x)
{
return CountOnes(~x);
}
// return the bit position (0..31) of the least significant bit
inline UInt32 LSBitPos(UInt32 x)
{
return CountTrailingZeroes(x & -(SInt32)x);
}
// isolate the least significant bit
inline UInt32 LSBit(UInt32 x)
{
return x & -(SInt32)x;
}
// return the bit position (0..31) of the most significant bit
inline UInt32 MSBitPos(UInt32 x)
{
return 31 - CountLeadingZeroes(x);
}
// isolate the most significant bit
inline UInt32 MSBit(UInt32 x)
{
return 1 << MSBitPos(x);
}
// Division optimized for power of 2 denominators
inline UInt32 DivInt(UInt32 numerator, UInt32 denominator)
{
if(IsPowerOfTwo(denominator))
return numerator >> (31 - CountLeadingZeroes(denominator));
else
return numerator/denominator;
}
#endif
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