94 lines
2.1 KiB
C++
94 lines
2.1 KiB
C++
#pragma once
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#include <solanaceae/file/file2.hpp>
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#include "./mio.hpp"
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#include <filesystem>
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#include <fstream>
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#include <iostream>
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#include <cstring>
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#include <cassert>
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struct File2RWMapped : public File2I {
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mio::ummap_sink _file_map;
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// TODO: add truncate support?
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// TODO: rw always true?
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File2RWMapped(std::string_view file_path, int64_t file_size = -1) : File2I(true, true) {
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std::filesystem::path native_file_path{file_path};
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if (!std::filesystem::exists(native_file_path)) {
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std::ofstream(native_file_path) << '\0'; // force create the file
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}
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_file_size = std::filesystem::file_size(native_file_path);
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if (file_size >= 0 && _file_size != file_size) {
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try {
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std::filesystem::resize_file(native_file_path, file_size); // ensure size, usually sparse
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} catch (...) {
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std::cerr << "FileRWMapped error: resizing file failed\n";
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return;
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}
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_file_size = std::filesystem::file_size(native_file_path);
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if (_file_size != file_size) {
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std::cerr << "FileRWMapped error: resizing file failed (size mismatch)\n";
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return;
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}
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}
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std::error_code err;
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// sink, is also read
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_file_map.map(native_file_path.u8string(), 0, _file_size, err);
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if (err) {
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std::cerr << "FileRWMapped error: mapping file failed " << err << "\n";
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return;
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}
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}
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virtual ~File2RWMapped(void) override {}
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bool isGood(void) override {
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return _file_map.is_mapped();
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}
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bool write(const ByteSpan data, int64_t pos = -1) override {
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// TODO: support streaming write
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if (pos < 0) {
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return false;
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}
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if (data.empty()) {
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return true; // false?
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}
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// file size is fix for mmaped files
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if (pos+data.size > _file_size) {
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return false;
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}
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std::memcpy(_file_map.data()+pos, data.ptr, data.size);
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return true;
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}
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ByteSpanWithOwnership read(uint64_t size, int64_t pos = -1) override {
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// TODO: support streaming read
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if (pos < 0) {
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assert(false && "streaming not implemented");
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return ByteSpan{};
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}
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if (pos+size > _file_size) {
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assert(false && "read past end");
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return ByteSpan{};
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}
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// return non-owning
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return ByteSpan{_file_map.data()+pos, size};
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}
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};
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