147 lines
4.8 KiB
C++
147 lines
4.8 KiB
C++
/*
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File: CATink.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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#if !defined(__CATink_h__)
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#define __CATink_h__
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//=============================================================================
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// Includes
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//=============================================================================
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// System Includes
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#if !defined(__COREAUDIO_USE_FLAT_INCLUDES__)
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#include <CoreServices/CoreServices.h>
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#else
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#include <CoreServices.h>
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#endif
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//=============================================================================
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// CATink
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//
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// A Tink is a small jump island that can make one function appear as if it
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// has many addresses. Note that Tinks are not supported for 64 bit environments
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// as the APIs that made tinks useful have been replaced by APIs that do away
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// with all the reasons for using a tink.
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//=============================================================================
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template <class F>
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class CATink
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{
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public:
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CATink(F proc) { Set(proc); }
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~CATink() { Set((F)0xDEADDEAD); } // jump to an obviously bad (odd) address if accessed after destruction
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#if TARGET_CPU_PPC
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void Set(F proc)
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{
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/*
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lis r11,0x1234
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00000000: 3D601234 lis r11,4660
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ori r11,r11,0x5678
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00000004: 616B5678 ori r11,r11,$5678
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mtctr r11
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00000008: 7D6903A6 mtctr r11
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bctr
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0000000C: 4E800420 bctr
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*/
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UInt32 p = UInt32(proc);
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mCode[0] = 0x3D600000 | (p >> 16);
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mCode[1] = 0x616B0000 | (p & 0xFFFF);
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mCode[2] = 0x7D6903A6;
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mCode[3] = 0x4E800420;
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MakeDataExecutable(mCode, sizeof(mCode));
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}
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operator F () { return F(mCode); }
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private:
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UInt32 mCode[4];
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#elif TARGET_CPU_X86
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void Set(F proc)
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{
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/*
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<tink>: push $0x12345678
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<tink+5>: ret
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<tink>: 0x34567868
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<tink+4>: 0x00e8c312
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*/
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UInt32 p = UInt32(proc);
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mCode[0] = ((p & 0xFFFFFF) << 8) | 0x00000068;
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mCode[1] = 0xCCCCC300 | (p >> 24);
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MakeDataExecutable(mCode, sizeof(mCode));
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}
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operator F () { return F(&mCode[0]); }
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private:
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UInt32 mCode[2];
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#else
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#warning: CPU not directly supported by CATink
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// For other CPU's, just wrap the function pointer for now.
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// this bypasses what we're trying to accomplish with the Tink
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// (multiple unique "instances" of a function), but it will at
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// least compile and run.
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void Set(F proc) { mProcPtr = proc; }
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operator F () { return mProcPtr; }
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private:
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F mProcPtr;
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#endif
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// Tinks cannot be allocated in STL Containers, so we make a few key methods private
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private:
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CATink(){}
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CATink(const CATink&){}
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CATink& operator=(const CATink&){ return *this;}
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};
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#endif
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