danicoin/src/Common/ArrayView.h
2015-07-30 16:22:07 +01:00

422 lines
13 KiB
C++
Executable file

// Copyright (c) 2012-2015, The CryptoNote developers, The Bytecoin developers
//
// This file is part of Bytecoin.
//
// Bytecoin is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Bytecoin 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 Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with Bytecoin. If not, see <http://www.gnu.org/licenses/>.
#pragma once
#include <cassert>
#include <cstddef>
#include <cstdint>
#include <limits>
namespace Common {
// 'ArrayView' is a pair of pointer to constant object of parametrized type and size.
// It is recommended to pass 'ArrayView' to procedures by value.
// 'ArrayView' supports 'EMPTY' and 'NIL' representations as follows:
// 'data' == 'nullptr' && 'size' == 0 - EMPTY NIL
// 'data' != 'nullptr' && 'size' == 0 - EMPTY NOTNIL
// 'data' == 'nullptr' && 'size' > 0 - Undefined
// 'data' != 'nullptr' && 'size' > 0 - NOTEMPTY NOTNIL
// For signed integer 'Size', 'ArrayView' with 'size' < 0 is undefined.
template<class Object = uint8_t, class Size = size_t> class ArrayView {
public:
typedef Object ObjectType;
typedef Size SizeType;
const static Size INVALID;
const static ArrayView EMPTY;
const static ArrayView NIL;
// Default constructor.
// Leaves object uninitialized. Any usage before initializing it is undefined.
ArrayView()
#ifndef NDEBUG
: data(nullptr), size(INVALID) // In debug mode, fill in object with invalid state (undefined).
#endif
{
}
// Direct constructor.
// The behavior is undefined unless 'arrayData' != 'nullptr' || 'arraySize' == 0
ArrayView(const Object* arrayData, Size arraySize) : data(arrayData), size(arraySize) {
assert(data != nullptr || size == 0);
}
// Constructor from C array.
// The behavior is undefined unless 'arrayData' != 'nullptr' || 'arraySize' == 0. Input state can be malformed using poiner conversions.
template<Size arraySize> ArrayView(const Object(&arrayData)[arraySize]) : data(arrayData), size(arraySize) {
assert(data != nullptr || size == 0);
}
// Copy constructor.
// Performs default action - bitwise copying of source object.
// The behavior is undefined unless 'other' 'ArrayView' is in defined state, that is 'data' != 'nullptr' || 'size' == 0
ArrayView(const ArrayView& other) : data(other.data), size(other.size) {
assert(data != nullptr || size == 0);
}
// Destructor.
// No special action is performed.
~ArrayView() {
}
// Copy assignment operator.
// The behavior is undefined unless 'other' 'ArrayView' is in defined state, that is 'data' != 'nullptr' || 'size' == 0
ArrayView& operator=(const ArrayView& other) {
assert(other.data != nullptr || other.size == 0);
data = other.data;
size = other.size;
return *this;
}
const Object* getData() const {
assert(data != nullptr || size == 0);
return data;
}
Size getSize() const {
assert(data != nullptr || size == 0);
return size;
}
// Return false if 'ArrayView' is not EMPTY.
// The behavior is undefined unless 'ArrayView' was initialized.
bool isEmpty() const {
assert(data != nullptr || size == 0);
return size == 0;
}
// Return false if 'ArrayView' is not NIL.
// The behavior is undefined unless 'ArrayView' was initialized.
bool isNil() const {
assert(data != nullptr || size == 0);
return data == nullptr;
}
// Get 'ArrayView' element by index.
// The behavior is undefined unless 'ArrayView' was initialized and 'index' < 'size'.
const Object& operator[](Size index) const {
assert(data != nullptr || size == 0);
assert(index < size);
return *(data + index);
}
// Get first element.
// The behavior is undefined unless 'ArrayView' was initialized and 'size' > 0
const Object& first() const {
assert(data != nullptr || size == 0);
assert(size > 0);
return *data;
}
// Get last element.
// The behavior is undefined unless 'ArrayView' was initialized and 'size' > 0
const Object& last() const {
assert(data != nullptr || size == 0);
assert(size > 0);
return *(data + (size - 1));
}
// Return a pointer to the first element.
// The behavior is undefined unless 'ArrayView' was initialized.
const Object* begin() const {
assert(data != nullptr || size == 0);
return data;
}
// Return a pointer after the last element.
// The behavior is undefined unless 'ArrayView' was initialized.
const Object* end() const {
assert(data != nullptr || size == 0);
return data + size;
}
// Compare elements of two arrays, return false if there is a difference.
// EMPTY and NIL arrays are considered equal.
// The behavior is undefined unless both arrays were initialized.
bool operator==(ArrayView other) const {
assert(data != nullptr || size == 0);
assert(other.data != nullptr || other.size == 0);
if (size == other.size) {
for (Size i = 0;; ++i) {
if (i == size) {
return true;
}
if (!(*(data + i) == *(other.data + i))) {
break;
}
}
}
return false;
}
// Compare elements two arrays, return false if there is no difference.
// EMPTY and NIL arrays are considered equal.
// The behavior is undefined unless both arrays were initialized.
bool operator!=(ArrayView other) const {
assert(data != nullptr || size == 0);
assert(other.data != nullptr || other.size == 0);
if (size == other.size) {
for (Size i = 0;; ++i) {
if (i == size) {
return false;
}
if (*(data + i) != *(other.data + i)) {
break;
}
}
}
return true;
}
// Return false if 'ArrayView' does not contain 'object' at the beginning.
// The behavior is undefined unless 'ArrayView' was initialized.
bool beginsWith(const Object& object) const {
assert(data != nullptr || size == 0);
if (size == 0) {
return false;
}
return *data == object;
}
// Return false if 'ArrayView' does not contain 'other' at the beginning.
// The behavior is undefined unless both arrays were initialized.
bool beginsWith(ArrayView other) const {
assert(data != nullptr || size == 0);
assert(other.data != nullptr || other.size == 0);
if (size >= other.size) {
for (Size i = 0;; ++i) {
if (i == other.size) {
return true;
}
if (!(*(data + i) == *(other.data + i))) {
break;
}
}
}
return false;
}
// Return false if 'ArrayView' does not contain 'object'.
// The behavior is undefined unless 'ArrayView' was initialized.
bool contains(const Object& object) const {
assert(data != nullptr || size == 0);
for (Size i = 0; i < size; ++i) {
if (*(data + i) == object) {
return true;
}
}
return false;
}
// Return false if 'ArrayView' does not contain 'other'.
// The behavior is undefined unless both arrays were initialized.
bool contains(ArrayView other) const {
assert(data != nullptr || size == 0);
assert(other.data != nullptr || other.size == 0);
if (size >= other.size) {
Size i = size - other.size;
for (Size j = 0; !(i < j); ++j) {
for (Size k = 0;; ++k) {
if (k == other.size) {
return true;
}
if (!(*(data + j + k) == *(other.data + k))) {
break;
}
}
}
}
return false;
}
// Return false if 'ArrayView' does not contain 'object' at the end.
// The behavior is undefined unless 'ArrayView' was initialized.
bool endsWith(const Object& object) const {
assert(data != nullptr || size == 0);
if (size == 0) {
return false;
}
return *(data + (size - 1)) == object;
}
// Return false if 'ArrayView' does not contain 'other' at the end.
// The behavior is undefined unless both arrays were initialized.
bool endsWith(ArrayView other) const {
assert(data != nullptr || size == 0);
assert(other.data != nullptr || other.size == 0);
if (size >= other.size) {
Size i = size - other.size;
for (Size j = 0;; ++j) {
if (j == other.size) {
return true;
}
if (!(*(data + i + j) == *(other.data + j))) {
break;
}
}
}
return false;
}
// Looks for the first occurence of 'object' in 'ArrayView',
// returns index or INVALID if there are no occurences.
// The behavior is undefined unless 'ArrayView' was initialized.
Size find(const Object& object) const {
assert(data != nullptr || size == 0);
for (Size i = 0; i < size; ++i) {
if (*(data + i) == object) {
return i;
}
}
return INVALID;
}
// Looks for the first occurence of 'other' in 'ArrayView',
// returns index or INVALID if there are no occurences.
// The behavior is undefined unless both arrays were initialized.
Size find(ArrayView other) const {
assert(data != nullptr || size == 0);
assert(other.data != nullptr || other.size == 0);
if (size >= other.size) {
Size i = size - other.size;
for (Size j = 0; !(i < j); ++j) {
for (Size k = 0;; ++k) {
if (k == other.size) {
return j;
}
if (!(*(data + j + k) == *(other.data + k))) {
break;
}
}
}
}
return INVALID;
}
// Looks for the last occurence of 'object' in 'ArrayView',
// returns index or INVALID if there are no occurences.
// The behavior is undefined unless 'ArrayView' was initialized.
Size findLast(const Object& object) const {
assert(data != nullptr || size == 0);
for (Size i = 0; i < size; ++i) {
if (*(data + (size - 1 - i)) == object) {
return size - 1 - i;
}
}
return INVALID;
}
// Looks for the first occurence of 'other' in 'ArrayView',
// returns index or INVALID if there are no occurences.
// The behavior is undefined unless both arrays were initialized.
Size findLast(ArrayView other) const {
assert(data != nullptr || size == 0);
assert(other.data != nullptr || other.size == 0);
if (size >= other.size) {
Size i = size - other.size;
for (Size j = 0; !(i < j); ++j) {
for (Size k = 0;; ++k) {
if (k == other.size) {
return i - j;
}
if (!(*(data + (i - j + k)) == *(other.data + k))) {
break;
}
}
}
}
return INVALID;
}
// Returns subarray of 'headSize' first elements.
// The behavior is undefined unless 'ArrayView' was initialized and 'headSize' <= 'size'.
ArrayView head(Size headSize) const {
assert(data != nullptr || size == 0);
assert(headSize <= size);
return ArrayView(data, headSize);
}
// Returns subarray of 'tailSize' last elements.
// The behavior is undefined unless 'ArrayView' was initialized and 'tailSize' <= 'size'.
ArrayView tail(Size tailSize) const {
assert(data != nullptr || size == 0);
assert(tailSize <= size);
return ArrayView(data + (size - tailSize), tailSize);
}
// Returns 'ArrayView' without 'headSize' first elements.
// The behavior is undefined unless 'ArrayView' was initialized and 'headSize' <= 'size'.
ArrayView unhead(Size headSize) const {
assert(data != nullptr || size == 0);
assert(headSize <= size);
return ArrayView(data + headSize, size - headSize);
}
// Returns 'ArrayView' without 'tailSize' last elements.
// The behavior is undefined unless 'ArrayView' was initialized and 'tailSize' <= 'size'.
ArrayView untail(Size tailSize) const {
assert(data != nullptr || size == 0);
assert(tailSize <= size);
return ArrayView(data, size - tailSize);
}
// Returns subarray starting at 'startIndex' and contaning 'endIndex' - 'startIndex' elements.
// The behavior is undefined unless 'ArrayView' was initialized and 'startIndex' <= 'endIndex' and 'endIndex' <= 'size'.
ArrayView range(Size startIndex, Size endIndex) const {
assert(data != nullptr || size == 0);
assert(startIndex <= endIndex && endIndex <= size);
return ArrayView(data + startIndex, endIndex - startIndex);
}
// Returns subarray starting at 'startIndex' and contaning 'sliceSize' elements.
// The behavior is undefined unless 'ArrayView' was initialized and 'startIndex' <= 'size' and 'startIndex' + 'sliceSize' <= 'size'.
ArrayView slice(Size startIndex, Size sliceSize) const {
assert(data != nullptr || size == 0);
assert(startIndex <= size && startIndex + sliceSize <= size);
return ArrayView(data + startIndex, sliceSize);
}
protected:
const Object* data;
Size size;
};
template<class Object, class Size> const Size ArrayView<Object, Size>::INVALID = std::numeric_limits<Size>::max();
template<class Object, class Size> const ArrayView<Object, Size> ArrayView<Object, Size>::EMPTY(reinterpret_cast<Object*>(1), 0);
template<class Object, class Size> const ArrayView<Object, Size> ArrayView<Object, Size>::NIL(nullptr, 0);
}