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idrec: add support for stdex::stream

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Signed-off-by: Simon Rozman <simon@rozman.si>
This commit is contained in:
Simon Rozman 2023-09-08 11:41:23 +02:00
parent b8cb07f456
commit 753da36672
1 changed files with 228 additions and 22 deletions
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250
include/stdex/idrec.hpp
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@ -6,11 +6,11 @@
#pragma once
#include "sal.hpp"
#include "stream.hpp"
#include <ios>
#include <istream>
#include <ostream>
namespace stdex {
namespace idrec {
///
@ -34,6 +34,26 @@ namespace stdex {
return false;
}
///
/// 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_ stdex::stream::basic_file& stream, _Out_ T_ID &id, _In_opt_ stdex::stream::fpos_t end = stdex::stream::fpos_max)
{
if (end == stdex::stream::fpos_max || stream.tell() < end) {
stream >> id;
return stream.ok();
} else
return false;
}
///
/// Skips current record data
@ -50,16 +70,40 @@ namespace stdex {
// Read record size.
T_SIZE size;
stream.read((char*)&size, sizeof(size));
if (!stream.good()) return false;
if (!stream.good()) _Unlikely_ return false;
// Skip the record data.
size += (T_SIZE)(ALIGN - size) % ALIGN;
stream.ignore(size);
if (!stream.good()) return false;
if (!stream.good()) _Unlikely_ return false;
return true;
}
///
/// 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_ stdex::stream::basic_file& stream)
{
// Read record size.
T_SIZE size;
stream >> size;
if (!stream.ok()) _Unlikely_ return false;
// Skip the record data.
size += (T_SIZE)(ALIGN - size) % ALIGN;
stream.skip(size);
if (!stream.ok()) _Unlikely_ return false;
return true;
}
///
/// Finds record data
@ -76,21 +120,44 @@ namespace stdex {
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 (!stream.good()) _Unlikely_ return false;
if (_id == id) {
// The record was found.
return true;
} else
ignore<T_SIZE, ALIGN>(stream);
}
return false;
}
///
/// 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_ stdex::stream::basic_file& stream, _In_ T_ID id, _In_opt_ stdex::stream::fpos_t end = stdex::stream::fpos_max)
{
T_ID _id;
while (end == stdex::stream::fpos_max || stream.tell() < end) {
stream >> _id;
if (!stream.ok()) _Unlikely_ return false;
if (_id == id) {
// The record was found.
return true;
} else
ignore<T_SIZE, ALIGN>(stream);
}
return false;
}
///
/// Writes record header
@ -106,17 +173,40 @@ namespace stdex {
std::streamoff start = stream.tellp();
// Write ID.
if (stream.fail()) return (std::streamoff)-1;
if (stream.fail()) _Unlikely_ 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;
if (stream.fail()) _Unlikely_ return (std::streamoff)-1;
T_SIZE size = 0;
stream.write((const char*)&size, sizeof(size));
return start;
}
///
/// 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>
stdex::stream::fpos_t open(_In_ stdex::stream::basic_file& stream, _In_ T_ID id)
{
auto start = stream.tell();
// Write ID.
if (!stream.ok()) _Unlikely_ return stdex::stream::fpos_max;
stream << id;
// Write 0 as a placeholder for data size.
if (!stream.ok()) _Unlikely_ return stdex::stream::fpos_max;
stream << (T_SIZE)0;
return start;
}
///
/// Updates record header
@ -131,8 +221,8 @@ namespace stdex {
{
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
size = static_cast<T_SIZE>(end - start - sizeof(T_ID) - sizeof(T_SIZE)),
remainder = static_cast<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.
@ -142,7 +232,7 @@ namespace stdex {
}
// Update the data size.
if (stream.fail()) return (std::streamoff)-1;
if (stream.fail()) _Unlikely_ return (std::streamoff)-1;
stream.seekp(start + sizeof(T_ID));
stream.write((const char*)&size, sizeof(size));
stream.seekp(end);
@ -150,6 +240,37 @@ namespace stdex {
return end;
}
///
/// 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>
stdex::stream::fpos_t close(_In_ stdex::stream::basic_file& stream, _In_ stdex::stream::fpos_t start)
{
auto end = stream.tell();
T_SIZE
size = static_cast<T_SIZE>(end - start - sizeof(T_ID) - sizeof(T_SIZE)),
remainder = static_cast<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_array(padding, sizeof(char), remainder);
end += remainder;
}
// Update the data size.
if (!stream.ok()) _Unlikely_ return stdex::stream::fpos_max;
stream.seek(start + sizeof(T_ID));
stream << size;
stream.seek(end);
return end;
}
///
/// Helper class for read/write of records to/from memory
@ -165,7 +286,6 @@ namespace stdex {
///
record(_In_ T &d) : data(d) {}
///
/// Constructs the class
///
@ -173,7 +293,6 @@ namespace stdex {
///
record(_In_ const T &d) : data((T&)d) {}
///
/// Returns record id
///
@ -182,7 +301,6 @@ namespace stdex {
return ID;
}
///
/// Assignment operator
///
@ -196,7 +314,6 @@ namespace stdex {
return *this;
}
///
/// Writes record header
///
@ -209,6 +326,17 @@ namespace stdex {
return stdex::idrec::open<T_ID, T_SIZE>(stream, ID);
}
///
/// 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 stdex::stream::foff_t open(_In_ stdex::stream::basic_file& stream)
{
return stdex::idrec::open<T_ID, T_SIZE>(stream, ID);
}
///
/// Updates record header
@ -223,6 +351,18 @@ namespace stdex {
return stdex::idrec::close<T_ID, T_SIZE, ALIGN>(stream, 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
///
static stdex::stream::foff_t close(_In_ stdex::stream::basic_file& stream, _In_ stdex::stream::foff_t start)
{
return stdex::idrec::close<T_ID, T_SIZE, ALIGN>(stream, start);
}
///
/// Finds record data
@ -239,13 +379,26 @@ namespace stdex {
return stdex::idrec::find<T_ID, T_SIZE, ALIGN>(stream, ID, end);
}
///
/// 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_ stdex::stream::basic_file& stream, _In_opt_ stdex::stream::foff_t end = stdex::stream::foff_max)
{
return stdex::idrec::find<T_ID, T_SIZE, ALIGN>(stream, ID, end);
}
T &data; ///< Record data reference
T &data; ///< Record data reference
};
};
};
///
/// Writes record to a stream
///
@ -259,14 +412,34 @@ std::ostream& operator <<(_In_ std::ostream& stream, _In_ const stdex::idrec::re
{
// Parameter r does not need to be passed by reference. It has only one field (data), which is a reference itself already.
std::streamoff start = r.open(stream);
if (stream.fail()) return stream;
auto start = r.open(stream);
if (stream.fail()) _Unlikely_ return stream;
stream << r.data;
r.close(stream, start);
return stream;
}
///
/// 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, T_ID ID, class T_SIZE, unsigned int ALIGN>
stdex::stream::basic_file& operator <<(_In_ stdex::stream::basic_file& stream, _In_ const stdex::idrec::record<T, T_ID, 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.
auto start = r.open(stream);
if (!stream.ok()) _Unlikely_ return stream;
stream << r.data;
r.close(stream, start);
return stream;
}
///
/// Reads record from a stream
@ -284,14 +457,47 @@ std::istream& operator >>(_In_ std::istream& stream, _In_ stdex::idrec::record<T
// Read data size.
T_SIZE size;
stream.read((char*)&size, sizeof(size));
if (!stream.good()) return stream;
if (!stream.good()) _Unlikely_ 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.
if (!stream.good()) _Unlikely_ return stream;
size += (T_SIZE)(ALIGN - size) % ALIGN;
size += static_cast<T_SIZE>((ALIGN - size) % ALIGN);
stream.seekg(start + size);
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, T_ID ID, class T_SIZE, unsigned int ALIGN>
stdex::stream::basic_file& operator >>(_In_ stdex::stream::basic_file& stream, _In_ stdex::idrec::record<T, T_ID, 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.
// Read data size.
T_SIZE size;
stream >> size;
if (!stream.ok()) _Unlikely_ return stream;
// Read data.
auto start = stream.tell();
{
stdex::stream::limiter limiter(stream, size, size);
limiter >> r.data;
if (!limiter.ok()) _Unlikely_ return stream;
}
size += static_cast<T_SIZE>((ALIGN - size) % ALIGN);
stream.seek(start + size);
return stream;
}