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85 lines
1.9 KiB
C
85 lines
1.9 KiB
C
/*
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* Copyright 1997, University Corporation for Atmospheric Research
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* See netcdf/COPYRIGHT file for copying and redistribution conditions.
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*/
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/* $Id: onstack.h,v 2.7 2006/09/15 20:40:39 ed Exp $ */
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#ifndef _ONSTACK_H_
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#define _ONSTACK_H_
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/**
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* This file provides definitions which allow us to
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* "allocate" arrays on the stack where possible.
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* (Where not possible, malloc and free are used.)
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*
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* The macro ALLOC_ONSTACK(name, type, nelems) is used to declare
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* an array of 'type' named 'name' which is 'nelems' long.
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* FREE_ONSTACK(name) is placed at the end of the scope of 'name'
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* to call 'free' if necessary.
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*
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* The macro ALLOC_ONSTACK wraps a call to alloca() on most systems.
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*/
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#ifdef _WIN32
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#ifdef HAVE_MALLOC_H
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#undef HAVE_ALLOCA
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#define HAVE_ALLOCA 1
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#include <malloc.h>
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#endif
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#endif
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#ifdef HAVE_ALLOCA
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/*
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* Implementation based on alloca()
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*/
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#if defined(__GNUC__)
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# if !defined(alloca)
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# define alloca __builtin_alloca
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# endif
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#else
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# ifdef HAVE_ALLOCA_H
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# include <alloca.h>
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# elif defined(_AIX)
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# pragma alloca
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# endif /* HAVE_ALLOCA_H */
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#endif /* __GNUC__ */
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# if !defined(ALLOCA_ARG_T)
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# define ALLOCA_ARG_T int /* the usual type of the alloca argument */
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# endif
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# define ALLOC_ONSTACK(name, type, nelems) \
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type *const name = (type *) alloca((ALLOCA_ARG_T)((nelems) * sizeof(type)))
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# define FREE_ONSTACK(name)
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#elif defined(_CRAYC) && !defined(__crayx1) && !__cplusplus && __STDC__ > 1
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/*
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* Cray C allows sizing of arrays with non-constant values.
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*/
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# define ALLOC_ONSTACK(name, type, nelems) \
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type name[nelems]
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# define FREE_ONSTACK(name)
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#elif defined(_WIN32) || defined(_WIN64)
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#include <malloc.h>
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#undef ALLOCA_ARG_T
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# define ALLOCA_ARG_T size_t
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#else
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/*
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* Default implementation. When all else fails, use malloc/free.
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*/
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# define ALLOC_ONSTACK(name, type, nelems) \
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type *const name = (type *) malloc((nelems) * sizeof(type))
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# define FREE_ONSTACK(name) \
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free(name)
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#endif
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#endif /* _ONSTACK_H_ */
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