ceb327789b
As per the const correctness rules, top-level const-ness of data in automatic scopes does not propagate outside of these scopes (unlike const-ness at lower levels, such as pointers to const data). Previously, const was used liberally, but inconsistently across the libpng codebase. Using const wherever applicable is not incorrect. However, _consistent_ use of const is difficult to maintain in such conditions. In conclusion, we shall continue to use const only where doing so is strictly necessary: 1. If a function guarantees that it will not modify an argument passed by pointer, the corresponding function parameter should be a pointer-to-const (const T *). 2. Static data should not be modified, therefore it should be const. Reference: Google C++ Style Guide https://google.github.io/styleguide/cppguide.html#Use_of_const
35 lines
880 B
C
35 lines
880 B
C
/* contrib/powerpc-vsx/linux_aux.c
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*
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* Copyright (c) 2017 Glenn Randers-Pehrson
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* Written by Vadim Barkov, 2017.
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* Last changed in libpng 1.6.29 [March 16, 2017]
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*
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* This code is released under the libpng license.
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* For conditions of distribution and use, see the disclaimer
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* and license in png.h
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*
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* STATUS: TESTED
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* BUG REPORTS: png-mng-implement@sourceforge.net
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*
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* png_have_vsx implemented for Linux by using the auxiliary vector mechanism.
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*
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* This code is strict ANSI-C and is probably moderately portable; it does
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* however use <stdio.h> and it assumes that /proc/cpuinfo is never localized.
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*/
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#include "sys/auxv.h"
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#include "png.h"
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static int
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png_have_vsx(png_structp png_ptr)
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{
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unsigned long auxv = getauxval(AT_HWCAP);
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PNG_UNUSED(png_ptr)
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if(auxv & (PPC_FEATURE_HAS_ALTIVEC|PPC_FEATURE_HAS_VSX))
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return 1;
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else
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return 0;
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}
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