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