image_framework_ymj/include/open3d/3rdparty/utils/CString.h
2024-12-06 16:25:16 +08:00

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/*
* Copyright (C) 2015 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef TNT_FILAMENT_CSTRING_H
#define TNT_FILAMENT_CSTRING_H
// NOTE: this header should not include STL headers
#include <utils/compiler.h>
#include <assert.h>
#include <stddef.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
namespace utils {
//! \privatesection
struct hashCStrings {
typedef const char* argument_type;
typedef size_t result_type;
result_type operator()(argument_type cstr) const noexcept {
size_t hash = 5381;
while (int c = *cstr++) {
hash = (hash * 33u) ^ size_t(c);
}
return hash;
}
};
//! \privatesection
struct equalCStrings {
typedef const char* first_argument_type;
typedef const char* second_argument_type;
typedef bool result_type;
bool operator()(const char* lhs, const char* rhs) const noexcept {
return !strcmp(lhs, rhs);
}
};
//! \privatesection
struct lessCStrings {
typedef const char* first_argument_type;
typedef const char* second_argument_type;
typedef bool result_type;
result_type operator()(first_argument_type lhs, second_argument_type rhs) const noexcept {
return strcmp(lhs, rhs) < 0;
}
};
// This can be used to creates a string from a string literal -- w/o underlying allocations.
// e.g.:
// StaticString s("Hello World!");
//
template <size_t N>
using StringLiteral = const char[N];
//! \publicsection
class UTILS_PUBLIC StaticString {
public:
using value_type = char;
using size_type = uint32_t;
using difference_type = int32_t;
using const_reference = const value_type&;
using const_pointer = const value_type*;
using const_iterator = const value_type*;
constexpr StaticString() noexcept = default;
// initialization from a string literal
template <size_t N>
StaticString(StringLiteral<N> const& other) noexcept // NOLINT(google-explicit-constructor)
: mString(other),
mLength(size_type(N - 1)),
mHash(computeHash(other)) {
}
// assignment from a string literal
template<size_t N>
StaticString& operator=(StringLiteral<N> const& other) noexcept {
mString = other;
mLength = size_type(N - 1);
mHash = computeHash(other);
return *this;
}
// helper to make a StaticString from a C string that is known to be a string literal
static constexpr StaticString make(const_pointer literal, size_t length) noexcept {
StaticString r;
r.mString = literal;
r.mLength = size_type(length);
size_type hash = 5381;
while (int c = *literal++) {
hash = (hash * 33u) ^ size_type(c);
}
r.mHash = hash;
return r;
}
static StaticString make(const_pointer literal) noexcept {
return make(literal, strlen(literal));
}
const_pointer c_str() const noexcept { return mString; }
const_pointer data() const noexcept { return mString; }
size_type size() const noexcept { return mLength; }
size_type length() const noexcept { return mLength; }
bool empty() const noexcept { return size() == 0; }
void clear() noexcept { mString = nullptr; mLength = 0; }
const_iterator begin() const noexcept { return mString; }
const_iterator end() const noexcept { return mString + mLength; }
const_iterator cbegin() const noexcept { return begin(); }
const_iterator cend() const noexcept { return end(); }
const_reference operator[](size_type pos) const noexcept {
assert(pos < size());
return begin()[pos];
}
const_reference at(size_type pos) const noexcept {
assert(pos < size());
return begin()[pos];
}
const_reference front() const noexcept {
assert(size());
return begin()[0];
}
const_reference back() const noexcept {
assert(size());
return begin()[size() - 1];
}
size_type getHash() const noexcept { return mHash; }
private:
const_pointer mString = nullptr;
size_type mLength = 0;
size_type mHash = 0;
template<size_t N>
static constexpr size_type computeHash(StringLiteral<N> const& s) noexcept {
size_type hash = 5381;
for (size_t i = 0; i < N - 1; i++) {
hash = (hash * 33u) ^ size_type(s[i]);
}
return hash;
}
int compare(const StaticString& rhs) const noexcept;
friend bool operator==(StaticString const& lhs, StaticString const& rhs) noexcept {
return (lhs.data() == rhs.data()) ||
((lhs.size() == rhs.size()) && !strncmp(lhs.data(), rhs.data(), lhs.size()));
}
friend bool operator!=(StaticString const& lhs, StaticString const& rhs) noexcept {
return !(lhs == rhs);
}
friend bool operator<(StaticString const& lhs, StaticString const& rhs) noexcept {
return lhs.compare(rhs) < 0;
}
friend bool operator>(StaticString const& lhs, StaticString const& rhs) noexcept {
return lhs.compare(rhs) > 0;
}
friend bool operator>=(StaticString const& lhs, StaticString const& rhs) noexcept {
return !(lhs < rhs);
}
friend bool operator<=(StaticString const& lhs, StaticString const& rhs) noexcept {
return !(lhs > rhs);
}
};
// ------------------------------------------------------------------------------------------------
class UTILS_PUBLIC CString {
public:
using value_type = char;
using size_type = uint32_t;
using difference_type = int32_t;
using reference = value_type&;
using const_reference = const value_type&;
using pointer = value_type*;
using const_pointer = const value_type*;
using iterator = value_type*;
using const_iterator = const value_type*;
CString() noexcept = default;
// Allocates memory and appends a null. This constructor can be used to hold arbitrary data
// inside the string (i.e. it can contain nulls or non-ASCII encodings).
CString(const char* cstr, size_t length);
// Allocates memory and copies traditional C string content. Unlike the above constructor, this
// does not alllow embedded nulls. This is explicit because this operation is costly.
explicit CString(const char* cstr);
template<size_t N>
explicit CString(StringLiteral<N> const& other) noexcept // NOLINT(google-explicit-constructor)
: CString(other, N - 1) {
}
CString(StaticString const& s) : CString(s.c_str(), s.size()) {}
CString(const CString& rhs);
CString(CString&& rhs) noexcept {
this->swap(rhs);
}
CString& operator=(const CString& rhs);
CString& operator=(CString&& rhs) noexcept {
this->swap(rhs);
return *this;
}
~CString() noexcept {
if (mData) {
free(mData - 1);
}
}
void swap(CString& other) noexcept {
// don't use std::swap(), we don't want an STL dependency in this file
auto *temp = mCStr;
mCStr = other.mCStr;
other.mCStr = temp;
}
const_pointer c_str() const noexcept { return mCStr; }
pointer c_str() noexcept { return mCStr; }
const_pointer c_str_safe() const noexcept { return mData ? c_str() : ""; }
const_pointer data() const noexcept { return c_str(); }
pointer data() noexcept { return c_str(); }
size_type size() const noexcept { return mData ? mData[-1].length : 0; }
size_type length() const noexcept { return size(); }
bool empty() const noexcept { return size() == 0; }
iterator begin() noexcept { return mCStr; }
iterator end() noexcept { return begin() + length(); }
const_iterator begin() const noexcept { return data(); }
const_iterator end() const noexcept { return begin() + length(); }
const_iterator cbegin() const noexcept { return begin(); }
const_iterator cend() const noexcept { return end(); }
CString& replace(size_type pos, size_type len, const CString& str) noexcept;
CString& insert(size_type pos, const CString& str) noexcept { return replace(pos, 0, str); }
const_reference operator[](size_type pos) const noexcept {
assert(pos < size());
return begin()[pos];
}
reference operator[](size_type pos) noexcept {
assert(pos < size());
return begin()[pos];
}
const_reference at(size_type pos) const noexcept {
assert(pos < size());
return begin()[pos];
}
reference at(size_type pos) noexcept {
assert(pos < size());
return begin()[pos];
}
reference front() noexcept {
assert(size());
return begin()[0];
}
const_reference front() const noexcept {
assert(size());
return begin()[0];
}
reference back() noexcept {
assert(size());
return begin()[size() - 1];
}
const_reference back() const noexcept {
assert(size());
return begin()[size() - 1];
}
// placement new declared as "throw" to avoid the compiler's null-check
inline void* operator new(size_t size, void* ptr) {
assert(ptr);
return ptr;
}
private:
struct Data {
size_type length;
};
// mCStr points to the C-string or nullptr. if non-null, mCStr is preceded by the string's size
union {
value_type *mCStr = nullptr;
Data* mData; // Data is stored at mData[-1]
};
int compare(const CString& rhs) const noexcept {
size_type lhs_size = size();
size_type rhs_size = rhs.size();
if (lhs_size < rhs_size) return -1;
if (lhs_size > rhs_size) return 1;
return strncmp(data(), rhs.data(), size());
}
friend bool operator==(CString const& lhs, StaticString const& rhs) noexcept {
return (lhs.data() == rhs.data()) ||
((lhs.size() == rhs.size()) && !strncmp(lhs.data(), rhs.data(), lhs.size()));
}
friend bool operator==(CString const& lhs, CString const& rhs) noexcept {
return (lhs.data() == rhs.data()) ||
((lhs.size() == rhs.size()) && !strncmp(lhs.data(), rhs.data(), lhs.size()));
}
friend bool operator!=(CString const& lhs, CString const& rhs) noexcept {
return !(lhs == rhs);
}
friend bool operator<(CString const& lhs, CString const& rhs) noexcept {
return lhs.compare(rhs) < 0;
}
friend bool operator>(CString const& lhs, CString const& rhs) noexcept {
return lhs.compare(rhs) > 0;
}
friend bool operator>=(CString const& lhs, CString const& rhs) noexcept {
return !(lhs < rhs);
}
friend bool operator<=(CString const& lhs, CString const& rhs) noexcept {
return !(lhs > rhs);
}
};
} // namespace utils
// FIXME: how could we not include this one?
// needed for std::hash, since implementation is inline, this would not cause
// binaries incompatibilities if another STL version was used.
#include <functional>
namespace std {
//! \privatesection
template<>
struct hash<utils::CString> {
typedef utils::CString argument_type;
typedef size_t result_type;
utils::hashCStrings hasher;
size_t operator()(const utils::CString& s) const noexcept {
return hasher(s.c_str());
}
};
//! \privatesection
template<>
struct hash<utils::StaticString> {
typedef utils::StaticString argument_type;
typedef size_t result_type;
size_t operator()(const utils::StaticString& s) const noexcept {
return s.getHash();
}
};
} // namespace std
#endif // TNT_FILAMENT_CSTRING_H