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upx/src/util/xspan.h
2023-01-29 11:39:57 +01:00

216 lines
7.8 KiB
C++

/* xspan -- a minimally invasive checked memory smart pointer
This file is part of the UPX executable compressor.
Copyright (C) 1996-2023 Markus Franz Xaver Johannes Oberhumer
All Rights Reserved.
UPX and the UCL library are free software; you can redistribute them
and/or modify them under the terms of the GNU General Public License as
published by the Free Software Foundation; either version 2 of
the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; see the file COPYING.
If not, write to the Free Software Foundation, Inc.,
59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
Markus F.X.J. Oberhumer
<markus@oberhumer.com>
*/
#pragma once
/*************************************************************************
// config and implementation
**************************************************************************/
#ifndef WITH_XSPAN
#define WITH_XSPAN 2
#endif
#if WITH_XSPAN
// automatic conversion to underlying pointer; do NOT enable this config as this
// defeats the main purpose of a checked pointer => use raw_bytes() as needed;
// and see xspan_fwd.h how to make this more convenient
#ifndef XSPAN_CONFIG_ENABLE_IMPLICIT_CONVERSION
#define XSPAN_CONFIG_ENABLE_IMPLICIT_CONVERSION 0
#endif
// allow automatic conversion PtrOrSpanOrNull => PtrOrSpan => Span (with run-time checks)
// choose between compile-time safety vs. possible run-time errors
#ifndef XSPAN_CONFIG_ENABLE_SPAN_CONVERSION
#define XSPAN_CONFIG_ENABLE_SPAN_CONVERSION 1
#endif
#include "xspan_impl.h"
#ifdef XSPAN_NAMESPACE_NAME
// help constructor to distinguish between number of elements and bytes
using XSPAN_NAMESPACE_NAME::XSpanCount;
using XSPAN_NAMESPACE_NAME::XSpanSizeInBytes;
// actual classes
using XSPAN_NAMESPACE_NAME::Ptr;
using XSPAN_NAMESPACE_NAME::PtrOrSpan;
using XSPAN_NAMESPACE_NAME::PtrOrSpanOrNull;
using XSPAN_NAMESPACE_NAME::Span;
// util
using XSPAN_NAMESPACE_NAME::raw_bytes; // overloaded for all classes
using XSPAN_NAMESPACE_NAME::raw_index_bytes; // overloaded for all classes
#endif
#endif // WITH_XSPAN
/*************************************************************************
// usage
//
// PtrOrSpanOrNull invariants: ptr is checked if ptr != null && base != null
// PtrOrSpan invariants: ptr is checked if base != null; ptr != null
// Span invariants: ptr is checked; ptr != null; base != null
//
// Ptr invariants: none; this is just a no-op pointer wrapper
**************************************************************************/
#if WITH_XSPAN >= 2
// fully checked
#define XSPAN_0(type) PtrOrSpanOrNull<type>
#define XSPAN_P(type) PtrOrSpan<type>
#define XSPAN_S(type) Span<type>
// create a value
#define XSPAN_0_MAKE(type, first, ...) (XSPAN_0(type)(first, ##__VA_ARGS__))
#define XSPAN_P_MAKE(type, first, ...) (XSPAN_P(type)(first, ##__VA_ARGS__))
#define XSPAN_S_MAKE(type, first, ...) (XSPAN_S(type)(first, ##__VA_ARGS__))
// define a variable
#define XSPAN_0_VAR(type, var, first, ...) XSPAN_0(type) var(first, ##__VA_ARGS__)
#define XSPAN_P_VAR(type, var, first, ...) XSPAN_P(type) var(first, ##__VA_ARGS__)
#define XSPAN_S_VAR(type, var, first, ...) XSPAN_S(type) var(first, ##__VA_ARGS__)
#elif WITH_XSPAN >= 1
// unchecked - just a no-op pointer wrapper, no extra functionality
#define XSPAN_0(type) Ptr<type>
#define XSPAN_P(type) Ptr<type>
#define XSPAN_S(type) Ptr<type>
// create a value
#define XSPAN_0_MAKE(type, first, ...) (XSPAN_0(type)(first))
#define XSPAN_P_MAKE(type, first, ...) (XSPAN_P(type)(first))
#define XSPAN_S_MAKE(type, first, ...) (XSPAN_S(type)(first))
// define a variable
#define XSPAN_0_VAR(type, var, first, ...) XSPAN_0(type) var(first)
#define XSPAN_P_VAR(type, var, first, ...) XSPAN_P(type) var(first)
#define XSPAN_S_VAR(type, var, first, ...) XSPAN_S(type) var(first)
#else // WITH_XSPAN
// unchecked regular pointers
// helper for implicit pointer conversions and MemBuffer overloads
template <class R, class T>
inline R *xspan_make_helper__(R * /*dummy*/, T *first) {
return first; // IMPORTANT: no cast here to detect bad usage
}
template <class R>
inline R *xspan_make_helper__(R * /*dummy*/, std::nullptr_t /*first*/) {
return nullptr;
}
template <class R>
inline R *xspan_make_helper__(R * /*dummy*/, MemBuffer &first) {
return (R *) membuffer_get_void_ptr(first);
}
#define XSPAN_0(type) type *
#define XSPAN_P(type) type *
#define XSPAN_S(type) type *
// create a value
#define XSPAN_0_MAKE(type, first, ...) (xspan_make_helper__((type *) nullptr, first))
#define XSPAN_P_MAKE(type, first, ...) (xspan_make_helper__((type *) nullptr, first))
#define XSPAN_S_MAKE(type, first, ...) (xspan_make_helper__((type *) nullptr, first))
// define a variable
#define XSPAN_0_VAR(type, var, first, ...) type *var = XSPAN_0_MAKE(type, first)
#define XSPAN_P_VAR(type, var, first, ...) type *var = XSPAN_P_MAKE(type, first)
#define XSPAN_S_VAR(type, var, first, ...) type *var = XSPAN_S_MAKE(type, first)
#endif // WITH_XSPAN
#if 1
// nicer names
#define SPAN_0 XSPAN_0
#define SPAN_P XSPAN_P
#define SPAN_S XSPAN_S
#define SPAN_0_MAKE XSPAN_0_MAKE
#define SPAN_P_MAKE XSPAN_P_MAKE
#define SPAN_S_MAKE XSPAN_S_MAKE
#define SPAN_0_VAR XSPAN_0_VAR
#define SPAN_P_VAR XSPAN_P_VAR
#define SPAN_S_VAR XSPAN_S_VAR
#endif
/*************************************************************************
// raw_bytes() - get underlying memory from checked buffers/pointers.
// This is overloaded by various utility classes like BoundedPtr,
// MemBuffer and XSpan.
//
// Note that the pointer type is retained, the "_bytes" hints size_in_bytes
**************************************************************************/
// default: for any regular pointer, raw_bytes() is just the pointer itself
template <class T>
inline
typename std::enable_if<std::is_pointer<T>::value && !std_is_bounded_array<T>::value, T>::type
raw_bytes(T ptr, size_t size_in_bytes) {
if (size_in_bytes > 0) {
if very_unlikely (ptr == nullptr)
throwInternalError("raw_bytes unexpected NULL ptr");
if very_unlikely (__acc_cte(VALGRIND_CHECK_MEM_IS_ADDRESSABLE(ptr, size_in_bytes) != 0))
throwInternalError("raw_bytes valgrind-check-mem");
}
return ptr;
}
// default: for any regular pointer, raw_index_bytes() is just "pointer + index"
// NOTE: index == number of elements, *NOT* size in bytes!
template <class T>
inline
typename std::enable_if<std::is_pointer<T>::value && !std_is_bounded_array<T>::value, T>::type
raw_index_bytes(T ptr, size_t index, size_t size_in_bytes) {
typedef typename std::remove_pointer<T>::type element_type;
if very_unlikely (ptr == nullptr)
throwInternalError("raw_index_bytes unexpected NULL ptr");
size_in_bytes = mem_size(sizeof(element_type), index, size_in_bytes); // assert size
if very_unlikely (__acc_cte(VALGRIND_CHECK_MEM_IS_ADDRESSABLE(ptr, size_in_bytes) != 0))
throwInternalError("raw_index_bytes valgrind-check-mem");
UNUSED(size_in_bytes);
return ptr + index;
}
// same for bounded arrays
template <class T, size_t N>
inline T *raw_bytes(T (&a)[N], size_t size_in_bytes) {
typedef T element_type;
if very_unlikely (size_in_bytes > mem_size(sizeof(element_type), N))
throwInternalError("raw_bytes out of range");
return a;
}
template <class T, size_t N>
inline T *raw_index_bytes(T (&a)[N], size_t index, size_t size_in_bytes) {
typedef T element_type;
return raw_bytes(a, mem_size(sizeof(element_type), index, size_in_bytes)) + index;
}
/* vim:set ts=4 sw=4 et: */