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// Copyright 2017 Elias Kosunen
//
// 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
//
// https://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.
//
// This file is a part of scnlib:
// https://github.com/eliaskosunen/scnlib
#if defined(SCN_HEADER_ONLY) && SCN_HEADER_ONLY
#define SCN_FILE_CPP
#endif
#include <scn/detail/error.h>
#include <scn/detail/file.h>
#include <scn/util/expected.h>
#include <cstdio>
#if SCN_POSIX
#include <fcntl.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#elif SCN_WINDOWS
#ifdef WIN32_LEAN_AND_MEAN
#define SCN_WIN32_LEAN_DEFINED 1
#else
#define WIN32_LEAN_AND_MEAN
#define SCN_WIN32_LEAN_DEFINED 0
#endif
#ifdef NOMINMAX
#define SCN_NOMINMAX_DEFINED 1
#else
#define NOMINMAX
#define SCN_NOMINMAX_DEFINED 0
#endif
#include <Windows.h>
#if !SCN_NOMINMAX_DEFINED
#undef NOMINMAX
#endif
#if !SCN_WIN32_LEAN_DEFINED
#undef WIN32_LEAN_AND_MEAN
#endif
#endif
namespace scn {
SCN_BEGIN_NAMESPACE
namespace detail {
SCN_FUNC native_file_handle native_file_handle::invalid()
{
#if SCN_WINDOWS
return {INVALID_HANDLE_VALUE};
#else
return {-1};
#endif
}
SCN_FUNC byte_mapped_file::byte_mapped_file(const char* filename)
{
#if SCN_POSIX
int fd = open(filename, O_RDONLY);
if (fd == -1) {
return;
}
struct stat s {
};
int status = fstat(fd, &s);
if (status == -1) {
close(fd);
return;
}
auto size = s.st_size;
auto ptr =
static_cast<char*>(mmap(nullptr, static_cast<size_t>(size),
PROT_READ, MAP_PRIVATE, fd, 0));
if (ptr == MAP_FAILED) {
close(fd);
return;
}
m_file.handle = fd;
m_map = span<char>{ptr, static_cast<size_t>(size)};
#elif SCN_WINDOWS
auto f = ::CreateFileA(
filename, GENERIC_READ, FILE_SHARE_READ | FILE_SHARE_WRITE,
nullptr, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, nullptr);
if (f == INVALID_HANDLE_VALUE) {
return;
}
LARGE_INTEGER _size;
if (::GetFileSizeEx(f, &_size) == 0) {
::CloseHandle(f);
return;
}
auto size = static_cast<size_t>(_size.QuadPart);
auto h = ::CreateFileMappingA(
f, nullptr, PAGE_READONLY,
#ifdef _WIN64
static_cast<DWORD>(size >> 32ull),
#else
DWORD{0},
#endif
static_cast<DWORD>(size & 0xffffffffull), nullptr);
if (h == INVALID_HANDLE_VALUE || h == nullptr) {
::CloseHandle(f);
return;
}
auto start = ::MapViewOfFile(h, FILE_MAP_READ, 0, 0, size);
if (!start) {
::CloseHandle(h);
::CloseHandle(f);
return;
}
m_file.handle = f;
m_map_handle.handle = h;
m_map = span<char>{static_cast<char*>(start), size};
#else
SCN_UNUSED(filename);
#endif
}
SCN_FUNC void byte_mapped_file::_destruct()
{
#if SCN_POSIX
munmap(m_map.data(), m_map.size());
close(m_file.handle);
#elif SCN_WINDOWS
::CloseHandle(m_map_handle.handle);
::CloseHandle(m_file.handle);
m_map_handle = native_file_handle::invalid();
#endif
m_file = native_file_handle::invalid();
m_map = span<char>{};
SCN_ENSURE(!valid());
}
} // namespace detail
namespace detail {
template <typename CharT>
struct basic_file_iterator_access {
using iterator = typename basic_file<CharT>::iterator;
basic_file_iterator_access(const iterator& it) : self(it) {}
SCN_NODISCARD expected<CharT> deref() const
{
SCN_EXPECT(self.m_file);
if (self.m_file->m_buffer.empty()) {
// no chars have been read
return self.m_file->_read_single();
}
if (!self.m_last_error) {
// last read failed
return self.m_last_error;
}
return self.m_file->_get_char_at(self.m_current);
}
SCN_NODISCARD bool eq(const iterator& o) const
{
if (self.m_file && (self.m_file == o.m_file || !o.m_file)) {
if (self.m_file->_is_at_end(self.m_current) &&
self.m_last_error.code() != error::end_of_range &&
!o.m_file) {
self.m_last_error = error{};
auto r = self.m_file->_read_single();
if (!r) {
self.m_last_error = r.error();
return !o.m_file || self.m_current == o.m_current ||
o.m_last_error.code() == error::end_of_range;
}
}
}
// null file == null file
if (!self.m_file && !o.m_file) {
return true;
}
// null file == eof file
if (!self.m_file && o.m_file) {
// lhs null, rhs potentially eof
return o.m_last_error.code() == error::end_of_range;
}
// eof file == null file
if (self.m_file && !o.m_file) {
// rhs null, lhs potentially eof
return self.m_last_error.code() == error::end_of_range;
}
// eof file == eof file
if (self.m_last_error == o.m_last_error &&
self.m_last_error.code() == error::end_of_range) {
return true;
}
return self.m_file == o.m_file && self.m_current == o.m_current;
}
const iterator& self;
};
} // namespace detail
template <>
SCN_FUNC expected<char> basic_file<char>::iterator::operator*() const
{
return detail::basic_file_iterator_access<char>(*this).deref();
}
template <>
SCN_FUNC expected<wchar_t> basic_file<wchar_t>::iterator::operator*() const
{
return detail::basic_file_iterator_access<wchar_t>(*this).deref();
}
template <>
SCN_FUNC bool basic_file<char>::iterator::operator==(
const basic_file<char>::iterator& o) const
{
return detail::basic_file_iterator_access<char>(*this).eq(o);
}
template <>
SCN_FUNC bool basic_file<wchar_t>::iterator::operator==(
const basic_file<wchar_t>::iterator& o) const
{
return detail::basic_file_iterator_access<wchar_t>(*this).eq(o);
}
template <>
SCN_FUNC expected<char> file::_read_single() const
{
SCN_EXPECT(valid());
int tmp = std::fgetc(m_file);
if (tmp == EOF) {
if (std::feof(m_file) != 0) {
return error(error::end_of_range, "EOF");
}
if (std::ferror(m_file) != 0) {
return error(error::source_error, "fgetc error");
}
return error(error::unrecoverable_source_error,
"Unknown fgetc error");
}
auto ch = static_cast<char>(tmp);
m_buffer.push_back(ch);
return ch;
}
template <>
SCN_FUNC expected<wchar_t> wfile::_read_single() const
{
SCN_EXPECT(valid());
wint_t tmp = std::fgetwc(m_file);
if (tmp == WEOF) {
if (std::feof(m_file) != 0) {
return error(error::end_of_range, "EOF");
}
if (std::ferror(m_file) != 0) {
return error(error::source_error, "fgetc error");
}
return error(error::unrecoverable_source_error,
"Unknown fgetc error");
}
auto ch = static_cast<wchar_t>(tmp);
m_buffer.push_back(ch);
return ch;
}
template <>
SCN_FUNC void file::_sync_until(std::size_t pos) noexcept
{
for (auto it = m_buffer.rbegin();
it != m_buffer.rend() - static_cast<std::ptrdiff_t>(pos); ++it) {
std::ungetc(static_cast<unsigned char>(*it), m_file);
}
}
template <>
SCN_FUNC void wfile::_sync_until(std::size_t pos) noexcept
{
for (auto it = m_buffer.rbegin();
it != m_buffer.rend() - static_cast<std::ptrdiff_t>(pos); ++it) {
std::ungetwc(static_cast<wint_t>(*it), m_file);
}
}
SCN_END_NAMESPACE
} // namespace scn
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