289 lines
8.5 KiB
Plaintext
289 lines
8.5 KiB
Plaintext
/*
|
|
SPDX-License-Identifier: MIT
|
|
Copyright © 2016-2022 Amebis
|
|
*/
|
|
|
|
#pragma once
|
|
|
|
#include <ios>
|
|
#include <istream>
|
|
#include <ostream>
|
|
|
|
|
|
namespace stdex {
|
|
namespace idrec {
|
|
///
|
|
/// Reads record ID
|
|
///
|
|
/// \param[in] stream Input stream
|
|
/// \param[out] id Record ID
|
|
/// \param[in] end Position limit. Default is -1 (no limit).
|
|
///
|
|
/// \returns
|
|
/// - \c true when succeeded
|
|
/// - \c false otherwise
|
|
///
|
|
template <class T_ID>
|
|
_Success_(return) bool read_id(_In_ std::istream& stream, _Out_ T_ID &id, _In_opt_ std::streamoff end = (std::streamoff)-1)
|
|
{
|
|
if (end == (std::streamoff)-1 || stream.tellg() < end) {
|
|
stream.read((char*)&id, sizeof(id));
|
|
return stream.good();
|
|
} else
|
|
return false;
|
|
}
|
|
|
|
|
|
///
|
|
/// Skips current record data
|
|
///
|
|
/// \param[in] stream Input stream
|
|
///
|
|
/// \returns
|
|
/// - \c true when successful
|
|
/// - \c false otherwise
|
|
///
|
|
template <class T_SIZE, unsigned int ALIGN>
|
|
bool ignore(_In_ std::istream& stream)
|
|
{
|
|
// Read record size.
|
|
T_SIZE size;
|
|
stream.read((char*)&size, sizeof(size));
|
|
if (!stream.good()) return false;
|
|
|
|
// Skip the record data.
|
|
size += (T_SIZE)(ALIGN - size) % ALIGN;
|
|
stream.ignore(size);
|
|
if (!stream.good()) return false;
|
|
|
|
return true;
|
|
}
|
|
|
|
|
|
///
|
|
/// Finds record data
|
|
///
|
|
/// \param[in] stream Input stream
|
|
/// \param[in] id Record ID
|
|
/// \param[in] end Position limit. Default is -1 (no limit).
|
|
///
|
|
/// \returns
|
|
/// - \c true when found
|
|
/// - \c false otherwise
|
|
///
|
|
template <class T_ID, class T_SIZE, unsigned int ALIGN>
|
|
bool find(_In_ std::istream& stream, _In_ T_ID id, _In_opt_ std::streamoff end = (std::streamoff)-1)
|
|
{
|
|
T_ID _id;
|
|
|
|
while (end == (std::streamoff)-1 || stream.tellg() < end) {
|
|
stream.read((char*)&_id, sizeof(_id));
|
|
if (!stream.good()) return false;
|
|
|
|
if (_id == id) {
|
|
// The record was found.
|
|
return true;
|
|
} else
|
|
ignore<T_SIZE, ALIGN>(stream);
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
|
|
///
|
|
/// Writes record header
|
|
///
|
|
/// \param[in] stream Output stream
|
|
/// \param[in] id Record ID
|
|
///
|
|
/// \returns Position of the record header start in \p stream. Save for later \c close call.
|
|
///
|
|
template <class T_ID, class T_SIZE>
|
|
std::streamoff open(_In_ std::ostream& stream, _In_ T_ID id)
|
|
{
|
|
std::streamoff start = stream.tellp();
|
|
|
|
// Write ID.
|
|
if (stream.fail()) return (std::streamoff)-1;
|
|
stream.write((const char*)&id, sizeof(id));
|
|
|
|
// Write 0 as a placeholder for data size.
|
|
if (stream.fail()) return (std::streamoff)-1;
|
|
T_SIZE size = 0;
|
|
stream.write((const char*)&size, sizeof(size));
|
|
|
|
return start;
|
|
}
|
|
|
|
|
|
///
|
|
/// Updates record header
|
|
///
|
|
/// \param[in] stream Output stream
|
|
/// \param[in] start Start position of the record in \p stream
|
|
///
|
|
/// \returns Position of the record end in \p stream
|
|
///
|
|
template <class T_ID, class T_SIZE, unsigned int ALIGN>
|
|
std::streamoff close(_In_ std::ostream& stream, _In_ std::streamoff start)
|
|
{
|
|
std::streamoff end = stream.tellp();
|
|
T_SIZE
|
|
size = (T_SIZE)(end - start - sizeof(T_ID) - sizeof(T_SIZE)),
|
|
remainder = (T_SIZE)(ALIGN - size) % ALIGN; // Number of bytes we need to add, to keep the data integral number of ALIGN blocks long
|
|
|
|
if (remainder) {
|
|
// Append padding.
|
|
static const char padding[ALIGN] = {};
|
|
stream.write(padding, remainder);
|
|
end += remainder;
|
|
}
|
|
|
|
// Update the data size.
|
|
if (stream.fail()) return (std::streamoff)-1;
|
|
stream.seekp(start + sizeof(T_ID));
|
|
stream.write((const char*)&size, sizeof(size));
|
|
stream.seekp(end);
|
|
|
|
return end;
|
|
}
|
|
|
|
|
|
///
|
|
/// Helper class for read/write of records to/from memory
|
|
///
|
|
template <class T, class T_ID, class T_SIZE, unsigned int ALIGN>
|
|
class record
|
|
{
|
|
public:
|
|
///
|
|
/// Constructs the class
|
|
///
|
|
/// \param[in] d Reference to record data
|
|
///
|
|
record(_In_ T &d) : data(d) {}
|
|
|
|
|
|
///
|
|
/// Constructs the class
|
|
///
|
|
/// \param[in] d Reference to record data
|
|
///
|
|
record(_In_ const T &d) : data((T&)d) {}
|
|
|
|
|
|
///
|
|
/// Assignment operator
|
|
///
|
|
/// \param[in] r Source record
|
|
///
|
|
/// \returns A const reference to this struct
|
|
///
|
|
const record<T, T_ID, T_SIZE, ALIGN>& operator =(_In_ const record<T, T_ID, T_SIZE, ALIGN> &r)
|
|
{
|
|
data = r.data;
|
|
return *this;
|
|
}
|
|
|
|
|
|
///
|
|
/// Writes record header
|
|
///
|
|
/// \param[in] stream Output stream
|
|
///
|
|
/// \returns Position of the record header start in \p stream. Save for later \c close call.
|
|
///
|
|
static std::streamoff open(_In_ std::ostream& stream)
|
|
{
|
|
return stdex::idrec::open<T_ID, T_SIZE>(stream, id);
|
|
}
|
|
|
|
|
|
///
|
|
/// Updates record header
|
|
///
|
|
/// \param[in] stream Output stream
|
|
/// \param[in] start Start position of the record in \p stream
|
|
///
|
|
/// \returns Position of the record end in \p stream
|
|
///
|
|
static std::streamoff close(_In_ std::ostream& stream, _In_ std::streamoff start)
|
|
{
|
|
return stdex::idrec::close<T_ID, T_SIZE, ALIGN>(stream, start);
|
|
}
|
|
|
|
|
|
///
|
|
/// Finds record data
|
|
///
|
|
/// \param[in] stream Input stream
|
|
/// \param[in] end Position limit. Default is -1 (no limit).
|
|
///
|
|
/// \returns
|
|
/// - \c true when found
|
|
/// - \c false otherwise
|
|
///
|
|
static bool find(_In_ std::istream& stream, _In_opt_ std::streamoff end = (std::streamoff)-1)
|
|
{
|
|
return stdex::idrec::find<T_ID, T_SIZE, ALIGN>(stream, id, end);
|
|
}
|
|
|
|
|
|
static const T_ID id; ///< Record id
|
|
T &data; ///< Record data reference
|
|
};
|
|
};
|
|
};
|
|
|
|
|
|
///
|
|
/// Writes record to a stream
|
|
///
|
|
/// \param[in] stream Output stream
|
|
/// \param[in] r Record
|
|
///
|
|
/// \returns The stream \p stream
|
|
///
|
|
template <class T, class T_ID, class T_SIZE, unsigned int ALIGN>
|
|
std::ostream& operator <<(_In_ std::ostream& stream, _In_ const stdex::idrec::record<T, T_ID, T_SIZE, ALIGN> r)
|
|
{
|
|
// Parameter r does not need to be passed by reference. It has only one field (data), which is a reference itself already. The id field is static anyway.
|
|
|
|
std::streamoff start = r.open(stream);
|
|
if (stream.fail()) return stream;
|
|
stream << r.data;
|
|
r.close(stream, start);
|
|
|
|
return stream;
|
|
}
|
|
|
|
|
|
///
|
|
/// Reads record from a stream
|
|
///
|
|
/// \param[in] stream Input stream
|
|
/// \param[out] r Record
|
|
///
|
|
/// \returns The stream \p stream
|
|
///
|
|
template <class T, class T_ID, class T_SIZE, unsigned int ALIGN>
|
|
std::istream& operator >>(_In_ std::istream& stream, _In_ stdex::idrec::record<T, T_ID, T_SIZE, ALIGN> r)
|
|
{
|
|
// Parameter r does not need to be passed by reference. It has only one field (data), which is a reference itself already. The id field is static anyway.
|
|
|
|
// Read data size.
|
|
T_SIZE size;
|
|
stream.read((char*)&size, sizeof(size));
|
|
if (!stream.good()) return stream;
|
|
|
|
// Read data.
|
|
std::streamoff start = stream.tellg();
|
|
stream >> r.data; // TODO: operator >> should not read past the record data! Make a size limited stream and read from it instead.
|
|
|
|
size += (T_SIZE)(ALIGN - size) % ALIGN;
|
|
stream.seekg(start + size);
|
|
|
|
return stream;
|
|
}
|