spectrum2/3rdparty/cpprestsdk/include/cpprest/rawptrstream.h
2015-11-19 15:19:14 +01:00

642 lines
25 KiB
C++

/***
* ==++==
*
* Copyright (c) Microsoft Corporation. All rights reserved.
* 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
* http://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 defines a stream buffer that is based on a raw pointer and block size. Unlike a vector-based
* stream buffer, the buffer cannot be expanded or contracted, it has a fixed capacity.
*
* For the latest on this and related APIs, please see http://casablanca.codeplex.com.
*
* =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
****/
#pragma once
#ifndef _CASA_RAWPTR_STREAMS_H
#define _CASA_RAWPTR_STREAMS_H
#include <vector>
#include <queue>
#include <algorithm>
#include <iterator>
#include "pplx/pplxtasks.h"
#include "cpprest/astreambuf.h"
#include "cpprest/streams.h"
namespace Concurrency { namespace streams {
// Forward declarations
template <typename _CharType> class rawptr_buffer;
namespace details {
/// <summary>
/// The basic_rawptr_buffer class serves as a memory-based steam buffer that supports both writing and reading
/// sequences of characters to and from a fixed-size block.
/// </summary>
template<typename _CharType>
class basic_rawptr_buffer : public streams::details::streambuf_state_manager<_CharType>
{
public:
typedef _CharType char_type;
typedef typename basic_streambuf<_CharType>::traits traits;
typedef typename basic_streambuf<_CharType>::int_type int_type;
typedef typename basic_streambuf<_CharType>::pos_type pos_type;
typedef typename basic_streambuf<_CharType>::off_type off_type;
/// <summary>
/// Constructor
/// </summary>
basic_rawptr_buffer()
: streambuf_state_manager<_CharType>(std::ios_base::in | std::ios_base::out),
m_data(nullptr),
m_current_position(0),
m_size(0)
{
}
/// <summary>
/// Destructor
/// </summary>
virtual ~basic_rawptr_buffer()
{
this->_close_read();
this->_close_write();
}
protected:
/// <summary>
/// can_seek is used to determine whether a stream buffer supports seeking.
/// </summary>
virtual bool can_seek() const { return this->is_open(); }
/// <summary>
/// <c>has_size<c/> is used to determine whether a stream buffer supports size().
/// </summary>
virtual bool has_size() const { return this->is_open(); }
/// <summary>
/// Gets the size of the stream, if known. Calls to <c>has_size</c> will determine whether
/// the result of <c>size</c> can be relied on.
/// </summary>
virtual utility::size64_t size() const
{
return utility::size64_t(m_size);
}
/// <summary>
/// Get the stream buffer size, if one has been set.
/// </summary>
/// <param name="direction">The direction of buffering (in or out)</param>
/// <remarks>An implementation that does not support buffering will always return '0'.</remarks>
virtual size_t buffer_size(std::ios_base::openmode = std::ios_base::in) const
{
return 0;
}
/// <summary>
/// Set the stream buffer implementation to buffer or not buffer.
/// </summary>
/// <param name="size">The size to use for internal buffering, 0 if no buffering should be done.</param>
/// <param name="direction">The direction of buffering (in or out)</param>
/// <remarks>An implementation that does not support buffering will silently ignore calls to this function and it will not have
/// any effect on what is returned by subsequent calls to buffer_size().</remarks>
virtual void set_buffer_size(size_t , std::ios_base::openmode = std::ios_base::in)
{
return;
}
/// <summary>
/// For any input stream, in_avail returns the number of characters that are immediately available
/// to be consumed without blocking. May be used in conjunction with <cref="::sbumpc method"/> and sgetn() to
/// read data without incurring the overhead of using tasks.
/// </summary>
virtual size_t in_avail() const
{
// See the comment in seek around the restiction that we do not allow read head to
// seek beyond the current size.
_ASSERTE(m_current_position <= m_size);
msl::safeint3::SafeInt<size_t> readhead(m_current_position);
msl::safeint3::SafeInt<size_t> writeend(m_size);
return (size_t)(writeend - readhead);
}
/// <summary>
/// Closes the stream buffer, preventing further read or write operations.
/// </summary>
/// <param name="mode">The I/O mode (in or out) to close for.</param>
virtual pplx::task<void> close(std::ios_base::openmode mode)
{
if (mode & std::ios_base::in)
{
this->_close_read().get(); // Safe to call get() here.
}
if (mode & std::ios_base::out)
{
this->_close_write().get(); // Safe to call get() here.
}
if ( !this->can_read() && !this->can_write() )
{
m_data = nullptr;
}
// Exceptions will be propagated out of _close_read or _close_write
return pplx::task_from_result();
}
virtual pplx::task<bool> _sync()
{
return pplx::task_from_result(true);
}
virtual pplx::task<int_type> _putc(_CharType ch)
{
if (m_current_position >= m_size)
return pplx::task_from_result<int_type>(traits::eof());
int_type retVal = (this->write(&ch, 1) == 1) ? static_cast<int_type>(ch) : traits::eof();
return pplx::task_from_result<int_type>(retVal);
}
virtual pplx::task<size_t> _putn(const _CharType *ptr, size_t count)
{
msl::safeint3::SafeInt<size_t> newSize = msl::safeint3::SafeInt<size_t>(count) + m_current_position;
if ( newSize > m_size )
return pplx::task_from_exception<size_t>(std::make_exception_ptr(std::runtime_error("Writing past the end of the buffer")));
return pplx::task_from_result<size_t>(this->write(ptr, count));
}
/// <summary>
/// Allocates a contiguous memory block and returns it.
/// </summary>
/// <param name="count">The number of characters to allocate.</param>
/// <returns>A pointer to a block to write to, null if the stream buffer implementation does not support alloc/commit.</returns>
_CharType* _alloc(size_t count)
{
if (!this->can_write()) return nullptr;
msl::safeint3::SafeInt<size_t> readhead(m_current_position);
msl::safeint3::SafeInt<size_t> writeend(m_size);
size_t space_left = (size_t)(writeend - readhead);
if (space_left < count) return nullptr;
// Let the caller copy the data
return (_CharType*)(m_data+m_current_position);
}
/// <summary>
/// Submits a block already allocated by the stream buffer.
/// </summary>
/// <param name="count">The number of characters to be committed.</param>
void _commit(size_t actual)
{
// Update the write position and satisfy any pending reads
update_current_position(m_current_position+actual);
}
/// <summary>
/// Gets a pointer to the next already allocated contiguous block of data.
/// </summary>
/// <param name="ptr">A reference to a pointer variable that will hold the address of the block on success.</param>
/// <param name="count">The number of contiguous characters available at the address in 'ptr.'</param>
/// <returns><c>true</c> if the operation succeeded, <c>false</c> otherwise.</returns>
/// <remarks>
/// A return of false does not necessarily indicate that a subsequent read operation would fail, only that
/// there is no block to return immediately or that the stream buffer does not support the operation.
/// The stream buffer may not de-allocate the block until <see cref="::release method" /> is called.
/// If the end of the stream is reached, the function will return <c>true</c>, a null pointer, and a count of zero;
/// a subsequent read will not succeed.
/// </remarks>
virtual bool acquire(_Out_ _CharType*& ptr, _Out_ size_t& count)
{
count = 0;
ptr = nullptr;
if (!this->can_read()) return false;
count = in_avail();
if (count > 0)
{
ptr = (_CharType*)(m_data+m_current_position);
return true;
}
else
{
ptr = nullptr;
// Can only be open for read OR write, not both. If there is no data then
// we have reached the end of the stream so indicate such with true.
return true;
}
}
/// <summary>
/// Releases a block of data acquired using <see cref="::acquire method"/>. This frees the stream buffer to de-allocate the
/// memory, if it so desires. Move the read position ahead by the count.
/// </summary>
/// <param name="ptr">A pointer to the block of data to be released.</param>
/// <param name="count">The number of characters that were read.</param>
virtual void release(_Out_writes_opt_ (count) _CharType *ptr, _In_ size_t count)
{
if (ptr != nullptr)
update_current_position(m_current_position + count);
}
virtual pplx::task<size_t> _getn(_Out_writes_ (count) _CharType *ptr, _In_ size_t count)
{
return pplx::task_from_result(this->read(ptr, count));
}
size_t _sgetn(_Out_writes_ (count) _CharType *ptr, _In_ size_t count)
{
return this->read(ptr, count);
}
virtual size_t _scopy(_Out_writes_ (count) _CharType *ptr, _In_ size_t count)
{
return this->read(ptr, count, false);
}
virtual pplx::task<int_type> _bumpc()
{
return pplx::task_from_result(this->read_byte(true));
}
virtual int_type _sbumpc()
{
return this->read_byte(true);
}
virtual pplx::task<int_type> _getc()
{
return pplx::task_from_result(this->read_byte(false));
}
int_type _sgetc()
{
return this->read_byte(false);
}
virtual pplx::task<int_type> _nextc()
{
if (m_current_position >= m_size-1)
return pplx::task_from_result(basic_streambuf<_CharType>::traits::eof());
this->read_byte(true);
return pplx::task_from_result(this->read_byte(false));
}
virtual pplx::task<int_type> _ungetc()
{
auto pos = seekoff(-1, std::ios_base::cur, std::ios_base::in);
if ( pos == (pos_type)traits::eof())
return pplx::task_from_result(traits::eof());
return this->getc();
}
/// <summary>
/// Gets the current read or write position in the stream.
/// </summary>
/// <param name="direction">The I/O direction to seek (see remarks)</param>
/// <returns>The current position. EOF if the operation fails.</returns>
/// <remarks>Some streams may have separate write and read cursors.
/// For such streams, the direction parameter defines whether to move the read or the write cursor.</remarks>
virtual pos_type getpos(std::ios_base::openmode mode) const
{
if ( ((mode & std::ios_base::in) && !this->can_read()) ||
((mode & std::ios_base::out) && !this->can_write()))
return static_cast<pos_type>(traits::eof());
if (mode == std::ios_base::in)
return (pos_type)m_current_position;
else if (mode == std::ios_base::out)
return (pos_type)m_current_position;
else
return (pos_type)traits::eof();
}
/// <summary>
/// Seeks to the given position.
/// </summary>
/// <param name="pos">The offset from the beginning of the stream.</param>
/// <param name="direction">The I/O direction to seek (see remarks).</param>
/// <returns>The position. EOF if the operation fails.</returns>
/// <remarks>Some streams may have separate write and read cursors. For such streams, the direction parameter defines whether to move the read or the write cursor.</remarks>
virtual pos_type seekpos(pos_type position, std::ios_base::openmode mode)
{
pos_type beg(0);
pos_type end(m_size);
if (position >= beg)
{
auto pos = static_cast<size_t>(position);
// Read head
if ((mode & std::ios_base::in) && this->can_read())
{
if (position <= end)
{
// We do not allow reads to seek beyond the end or before the start position.
update_current_position(pos);
return static_cast<pos_type>(m_current_position);
}
}
// Write head
if ((mode & std::ios_base::out) && this->can_write())
{
// Update write head and satisfy read requests if any
update_current_position(pos);
return static_cast<pos_type>(m_current_position);
}
}
return static_cast<pos_type>(traits::eof());
}
/// <summary>
/// Seeks to a position given by a relative offset.
/// </summary>
/// <param name="offset">The relative position to seek to</param>
/// <param name="way">The starting point (beginning, end, current) for the seek.</param>
/// <param name="mode">The I/O direction to seek (see remarks)</param>
/// <returns>The position. EOF if the operation fails.</returns>
/// <remarks>Some streams may have separate write and read cursors.
/// For such streams, the mode parameter defines whether to move the read or the write cursor.</remarks>
virtual pos_type seekoff(off_type offset, std::ios_base::seekdir way, std::ios_base::openmode mode)
{
pos_type beg = 0;
pos_type cur = static_cast<pos_type>(m_current_position);
pos_type end = static_cast<pos_type>(m_size);
switch ( way )
{
case std::ios_base::beg:
return seekpos(beg + offset, mode);
case std::ios_base::cur:
return seekpos(cur + offset, mode);
case std::ios_base::end:
return seekpos(end + offset, mode);
default:
return static_cast<pos_type>(traits::eof());
}
}
private:
template<typename _CharType1> friend class ::concurrency::streams::rawptr_buffer;
/// <summary>
/// Constructor
/// </summary>
/// <param name="data">The address (pointer to) the memory block.</param>
/// <param name="size">The memory block size, measured in number of characters.</param>
basic_rawptr_buffer(const _CharType* data, size_t size)
: streambuf_state_manager<_CharType>(std::ios_base::in),
m_data(const_cast<_CharType*>(data)),
m_size(size),
m_current_position(0)
{
validate_mode(std::ios_base::in);
}
/// <summary>
/// Constructor
/// </summary>
/// <param name="data">The address (pointer to) the memory block.</param>
/// <param name="size">The memory block size, measured in number of characters.</param>
/// <param name="mode">The stream mode (in, out, etc.).</param>
basic_rawptr_buffer(_CharType* data, size_t size, std::ios_base::openmode mode)
: streambuf_state_manager<_CharType>(mode),
m_data(data),
m_size(size),
m_current_position(0)
{
validate_mode(mode);
}
static void validate_mode(std::ios_base::openmode mode)
{
// Disallow simultaneous use of the stream buffer for writing and reading.
if ((mode & std::ios_base::in) && (mode & std::ios_base::out))
throw std::invalid_argument("this combination of modes on raw pointer stream not supported");
}
/// <summary>
/// Determines if the request can be satisfied.
/// </summary>
bool can_satisfy(size_t) const
{
// We can always satisfy a read, at least partially, unless the
// read position is at the very end of the buffer.
return (in_avail() > 0);
}
/// <summary>
/// Reads a byte from the stream and returns it as int_type.
/// Note: This routine must only be called if can_satisfy() returns true.
/// </summary>
int_type read_byte(bool advance = true)
{
_CharType value;
auto read_size = this->read(&value, 1, advance);
return read_size == 1 ? static_cast<int_type>(value) : traits::eof();
}
/// <summary>
/// Reads up to count characters into ptr and returns the count of characters copied.
/// The return value (actual characters copied) could be <= count.
/// Note: This routine must only be called if can_satisfy() returns true.
/// </summary>
size_t read(_Out_writes_ (count) _CharType *ptr, _In_ size_t count, bool advance = true)
{
if (!can_satisfy(count))
return 0;
msl::safeint3::SafeInt<size_t> request_size(count);
msl::safeint3::SafeInt<size_t> read_size = request_size.Min(in_avail());
size_t newPos = m_current_position + read_size;
auto readBegin = m_data + m_current_position;
auto readEnd = m_data + newPos;
#ifdef _WIN32
// Avoid warning C4996: Use checked iterators under SECURE_SCL
std::copy(readBegin, readEnd, stdext::checked_array_iterator<_CharType *>(ptr, count));
#else
std::copy(readBegin, readEnd, ptr);
#endif // _WIN32
if (advance)
{
update_current_position(newPos);
}
return (size_t) read_size;
}
/// <summary>
/// Write count characters from the ptr into the stream buffer
/// </summary>
size_t write(const _CharType *ptr, size_t count)
{
if (!this->can_write() || (count == 0)) return 0;
msl::safeint3::SafeInt<size_t> newSize = msl::safeint3::SafeInt<size_t>(count) +m_current_position;
if ( newSize > m_size )
throw std::runtime_error("Writing past the end of the buffer");
// Copy the data
#ifdef _WIN32
// Avoid warning C4996: Use checked iterators under SECURE_SCL
std::copy(ptr, ptr + count, stdext::checked_array_iterator<_CharType *>(m_data, m_size, m_current_position));
#else
std::copy(ptr, ptr + count, m_data+m_current_position);
#endif // _WIN32
// Update write head and satisfy pending reads if any
update_current_position(newSize);
return count;
}
/// <summary>
/// Updates the current read or write position
/// </summary>
void update_current_position(size_t newPos)
{
// The new write head
m_current_position = newPos;
_ASSERTE(m_current_position <= m_size);
}
// The actual memory block
_CharType* m_data;
// The size of the memory block
size_t m_size;
// Read/write head
size_t m_current_position;
};
} // namespace details
/// <summary>
/// The <c>rawptr_buffer</c> class serves as a memory-based stream buffer that supports reading
/// sequences of characters to or from a fixed-size block. Note that it cannot be used simultaneously for reading as well as writing.
/// </summary>
/// <typeparam name="_CharType">
/// The data type of the basic element of the <c>rawptr_buffer</c>.
/// </typeparam>
template<typename _CharType>
class rawptr_buffer : public streambuf<_CharType>
{
public:
typedef _CharType char_type;
/// <summary>
/// Create a rawptr_buffer given a pointer to a memory block and the size of the block.
/// </summary>
/// <param name="data">The address (pointer to) the memory block.</param>
/// <param name="size">The memory block size, measured in number of characters.</param>
rawptr_buffer(const char_type* data, size_t size)
: streambuf<char_type>(std::shared_ptr<details::basic_rawptr_buffer<char_type>>(new details::basic_rawptr_buffer<char_type>(data, size)))
{
}
/// <summary>
/// Create a rawptr_buffer given a pointer to a memory block and the size of the block.
/// </summary>
/// <param name="data">The address (pointer to) the memory block.</param>
/// <param name="size">The memory block size, measured in number of characters.</param>
rawptr_buffer(char_type* data, size_t size, std::ios_base::openmode mode = std::ios::out)
: streambuf<char_type>(std::shared_ptr<details::basic_rawptr_buffer<char_type>>(new details::basic_rawptr_buffer<char_type>(data, size, mode)))
{
}
/// <summary>
/// Default constructor.
/// </summary>
rawptr_buffer()
{
}
};
/// <summary>
/// The rawptr_stream class is used to create memory-backed streams that support writing or reading
/// sequences of characters to / from a fixed-size block.
/// </summary>
/// <typeparam name="_CharType">
/// The data type of the basic element of the <c>rawptr_stream</c>.
/// </typeparam>
template<typename _CharType>
class rawptr_stream
{
public:
typedef _CharType char_type;
typedef rawptr_buffer<_CharType> buffer_type;
/// <summary>
/// Create a rawptr-stream given a pointer to a read-only memory block and the size of the block.
/// </summary>
/// <param name="data">The address (pointer to) the memory block.</param>
/// <param name="size">The memory block size, measured in number of characters.</param>
/// <returns>An opened input stream.</returns>
static concurrency::streams::basic_istream<char_type> open_istream(const char_type* data, size_t size)
{
return concurrency::streams::basic_istream<char_type>(buffer_type(data, size));
}
/// <summary>
/// Create a rawptr-stream given a pointer to a writable memory block and the size of the block.
/// </summary>
/// <param name="data">The address (pointer to) the memory block.</param>
/// <param name="size">The memory block size, measured in number of characters.</param>
/// <returns>An opened input stream.</returns>
static concurrency::streams::basic_istream<char_type> open_istream(char_type* data, size_t size)
{
return concurrency::streams::basic_istream<char_type>(buffer_type(data, size, std::ios::in));
}
/// <summary>
/// Create a rawptr-stream given a pointer to a writable memory block and the size of the block.
/// </summary>
/// <param name="data">The address (pointer to) the memory block.</param>
/// <param name="size">The memory block size, measured in number of characters.</param>
/// <returns>An opened output stream.</returns>
static concurrency::streams::basic_ostream<char_type> open_ostream(char_type* data, size_t size)
{
return concurrency::streams::basic_ostream<char_type>(buffer_type(data, size, std::ios::out));
}
};
}} // namespaces
#endif