133 lines
2.8 KiB
C++
133 lines
2.8 KiB
C++
// Copyright ⓒ 2018-2021 ThePhD.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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//
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// See https://github.com/ThePhD/out_ptr/blob/master/docs/out_ptr.adoc for documentation.
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#include <ztd/out_ptr/out_ptr.hpp>
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#include <assert.hpp>
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#include <iostream>
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#include <array>
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#include <cstdio>
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#include <cstddef>
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#ifdef _WIN32
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#include <io.h>
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#include <fcntl.h>
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#else
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// Some functions to achieve cross-platform parity
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#include <unistd.h>
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int fopen_s(FILE** f, const char* name, const char* mode) {
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int ret = 0;
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OUT_PTR_C_ASSERT(f);
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*f = fopen(name, mode);
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/* Can't be sure about 1-to-1 mapping of errno and MS' errno_t */
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if (!*f)
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ret = errno;
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return ret;
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}
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#endif // Windows
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struct fd {
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int handle;
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fd()
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: fd(nullptr) {
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}
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fd(std::nullptr_t)
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: handle(static_cast<intptr_t>(-1)) {
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}
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fd(FILE* f)
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#ifdef _WIN32
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: handle(f ? _fileno(f) : static_cast<intptr_t>(-1)){
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#else
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: handle(f ? fileno(f) : static_cast<intptr_t>(-1)) {
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#endif // Windows
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}
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operator FILE*() const {
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if (!*this)
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return nullptr;
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#ifdef _WIN32
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return _fdopen(handle, "rb");
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#else
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return fdopen(handle, "rb");
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#endif // Windows
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}
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explicit operator bool() const {
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return *this != nullptr;
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}
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bool operator==(std::nullptr_t) const {
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return handle == -1;
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}
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bool operator!=(std::nullptr_t) const {
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return handle != -1;
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}
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bool operator==(const fd& fd) const {
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return handle == fd.handle;
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}
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bool operator!=(const fd& fd) const {
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return handle != fd.handle;
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}
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bool operator==(int fdhandle) const {
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return handle == fdhandle;
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}
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bool operator!=(int fdhandle) const {
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return handle != fdhandle;
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}
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};
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struct fd_deleter {
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using pointer = fd;
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void operator()(fd des) const {
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if (des.handle != -1) {
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#ifdef _WIN32
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_close(des.handle);
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#else
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close(des.handle);
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#endif // Windows
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}
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}
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};
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int main() {
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std::unique_ptr<int, fd_deleter> my_unique_fd;
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auto err = fopen_s(ztd::out_ptr::out_ptr<FILE*>(my_unique_fd), "prod.csv", "r+b");
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// check err, then work with fd
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if (err != 0) {
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// something horrible happened, handle etc. etc.
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std::cout << "Error is non-zero, could not open prod.csv with a raw handle." << std::endl;
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}
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else {
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std::cout << "Opened prod.csv with a raw handle!" << std::endl;
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}
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return 0;
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}
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