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Atmosphere/libraries/libstratosphere/source/ncm/ncm_file_mapper_file.hpp

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4.3 KiB
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/*
* Copyright (c) Atmosphère-NX
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope 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. If not, see <http://www.gnu.org/licenses/>.
*/
#pragma once
#include <stratosphere.hpp>
namespace ams::ncm {
class FileMapperFile {
public:
enum class OpenMode {
Read,
ReadWrite,
ReadWriteAppend,
};
private:
const char *m_path;
OpenMode m_mode;
util::optional<fs::FileHandle> m_file;
size_t m_file_size;
size_t m_max_size;
public:
FileMapperFile() : m_file(util::nullopt) { /* ... */ }
~FileMapperFile() {
this->Finalize();
}
Result Initialize(const char *path, OpenMode mode) {
/* Set our path/mode. */
m_path = path;
m_mode = mode;
/* Ensure we're open. */
R_TRY(this->EnsureOpen());
/* Get the file size. */
s64 size;
R_TRY(fs::GetFileSize(std::addressof(size), m_file.value()));
/* Set our file size/loaded size. */
m_file_size = static_cast<size_t>(size);
m_max_size = static_cast<size_t>(size);
R_SUCCEED();
}
void Finalize() {
/* If we have a file, close (and flush) it. */
if (m_file.has_value()) {
if (m_mode != OpenMode::Read) {
R_ABORT_UNLESS(fs::FlushFile(m_file.value()));
}
fs::CloseFile(m_file.value());
m_file = util::nullopt;
}
}
size_t GetFileSize() const { return m_file_size; }
size_t GetMaxSize() const { return m_max_size; }
Result Read(size_t offset, void *dst, size_t size) {
/* Determine the end offset. */
const size_t end_offset = offset + size;
/* Unless we're allowed to append, we need to have a big enough file. */
if (m_mode != OpenMode::ReadWriteAppend) {
R_UNLESS(end_offset <= m_file_size, ncm::ResultMapperInvalidArgument());
}
/* Clear the output. */
std::memset(dst, 0, size);
/* Check that our offset is valid. */
R_UNLESS(offset <= m_file_size, ncm::ResultMapperInvalidArgument());
/* Ensure we're open. */
R_TRY(this->EnsureOpen());
/* Read what we can. */
const size_t read_size = (offset + size >= m_file_size) ? (m_file_size - offset) : size;
AMS_ASSERT(read_size >= size);
R_TRY(fs::ReadFile(m_file.value(), offset, dst, read_size));
/* Update our max size. */
m_max_size = std::max<size_t>(m_max_size, offset + read_size);
R_SUCCEED();
}
private:
Result EnsureOpen() {
/* If we've opened, we're done. */
R_SUCCEED_IF(m_file.has_value());
/* Open based on our mode. */
fs::FileHandle file;
switch (m_mode) {
case OpenMode::Read: R_TRY(fs::OpenFile(std::addressof(file), m_path, fs::OpenMode_Read)); break;
case OpenMode::ReadWrite: R_TRY(fs::OpenFile(std::addressof(file), m_path, fs::OpenMode_ReadWrite)); break;
case OpenMode::ReadWriteAppend: R_TRY(fs::OpenFile(std::addressof(file), m_path, fs::OpenMode_All)); break;
AMS_UNREACHABLE_DEFAULT_CASE();
}
/* Set our file. */
m_file = file;
R_SUCCEED();
}
};
}