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/* IBM_PROLOG_BEGIN_TAG */
/* This is an automatically generated prolog. */
/* */
/* $Source: import/hwpf/fapi2/include/buffer_stream.H $ */
/* */
/* OpenPOWER HCODE Project */
/* */
/* COPYRIGHT 2016,2017 */
/* [+] International Business Machines Corp. */
/* */
/* */
/* 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. */
/* */
/* IBM_PROLOG_END_TAG */
/**
* @file buffer_stream.H
* @brief Utility classes for streaming data into or out of fapi2::variable_buffer
*/
#ifndef BUFFER_STREAM_H_
#define BUFFER_STREAM_H_
#include <fapi2.H>
namespace fapi2
{
/** @name Utility classes for streaming data into or out of fapi2::variable_buffer */
//@{
/**
* @brief Wrapper class for variable_buffer to write OT-sized chunks into the buffer;
* keeps track of write offset and advances it with each put operation.
*/
template<typename OT>
class fixed_buffer_ostream
{
public:
typedef fapi2::variable_buffer::bits_type bits_type;
typedef fapi2::variable_buffer::unit_type unit_type;
/**
* @brief Constructor. Initializes write position to zero.
* @param[in,out] io_buffer The buffer to wrap
* @param[in] i_start_offset Offset (in OTs, not bits) in the buffer to start writing from.
* Defaults to the beginning of the buffer.
*/
fixed_buffer_ostream(fapi2::variable_buffer& io_buffer, unit_type i_start_offset = 0) :
iv_buffer(io_buffer), iv_offset(i_start_offset) {}
/**
* @brief Write a value into the buffer and advance the write pointer.
* The buffer must be appropriately sized to accept the value at the current write pointer.
* @param[in] i_value The value to write
* @return the buffer's return code
*/
fapi2::ReturnCode append(OT i_value)
{
return iv_buffer.set<OT>(i_value, iv_offset++);
}
/**
* @brief Return the amount of bits (not OTs) written to the buffer so far
* @return the amount of bits (not OTs) written to the buffer so far
*/
bits_type size()
{
return iv_offset * sizeof(OT) * 8;
}
private:
fapi2::variable_buffer& iv_buffer;
fapi2::variable_buffer::unit_type iv_offset;
};
/**
* @brief Similar to buffer_ostream, but not restricted to fixed chunks.
* Slower because it uses insert() instead of set().
*/
class buffer_ostream
{
public:
typedef fapi2::variable_buffer::bits_type bits_type;
/**
* @brief Constructor. Initializes write position to zero.
* @param[in,out] io_buffer The buffer to wrap
* @param[in] i_start_offset Offset inside the buffer to start writing from.
* Defaults to the beginning of the buffer.
*/
buffer_ostream(fapi2::variable_buffer& io_buffer, bits_type i_start_offset = 0) :
iv_buffer(io_buffer), iv_offset(i_start_offset) {}
/**
* @brief Write a left-aligned value into the buffer and advance the write pointer.
* The buffer must be appropriately sized to accept the value at the current write pointer.
* @param[in] i_data The data to write
* @param[in] i_len Amount of bits to write; defaults to ALL OF THEM
* @param[in] i_sourceStart Start offset at which to start reading from i_data; defaults to zero
* @return the buffer's return code
*/
template<typename OT>
fapi2::ReturnCode append(const OT& i_data, bits_type i_len = ~0, bits_type i_sourceStart = 0)
{
if (i_len == static_cast<bits_type>(~0))
{
i_len = parameterTraits<OT>::bit_length();
}
fapi2::ReturnCode rc = iv_buffer.insert(i_data, iv_offset, i_len, i_sourceStart);
if (rc == fapi2::FAPI2_RC_SUCCESS)
{
iv_offset += i_len;
}
return rc;
}
/**
* @brief Write a right-aligned value into the buffer and advance the write pointer.
* The buffer must be appropriately sized to accept the value at the current write pointer.
* @param[in] i_data The data to write
* @param[in] i_len Amount of bits to write; defaults to ALL OF THEM
* @return the buffer's return code
*/
template<typename OT>
fapi2::ReturnCode appendFromRight(const OT& i_data, bits_type i_len = ~0)
{
if (i_len == static_cast<bits_type>(~0))
{
i_len = parameterTraits<OT>::bit_length();
}
fapi2::ReturnCode rc = iv_buffer.insertFromRight(i_data, iv_offset, i_len);
if (rc == fapi2::FAPI2_RC_SUCCESS)
{
iv_offset += i_len;
}
return rc;
}
/**
* @brief Return the amount of bits written into the buffer so far
* @return the amount of bits written into the buffer so far
*/
bits_type size()
{
return iv_offset;
}
private:
fapi2::variable_buffer& iv_buffer;
bits_type iv_offset;
};
/**
* @brief Wrapper class for variable_buffer to to read OT-sized chunks out of the buffer;
* keeps track of read offset and advances it with each read operation.
*/
template<typename OT>
class fixed_buffer_istream
{
public:
typedef fapi2::variable_buffer::bits_type bits_type;
typedef fapi2::variable_buffer::unit_type unit_type;
/**
* @brief Constructor.
* @param[in,out] io_buffer The buffer to wrap
* @param[in] i_start_offset Offset (in OTs, not bits) in the buffer to start reading from.
* Defaults to the beginning of the buffer.
*/
fixed_buffer_istream(fapi2::variable_buffer& io_buffer, unit_type i_start_offset = 0) :
iv_buffer(io_buffer), iv_offset(i_start_offset) {}
/**
* @brief Pull the next OT out of the buffer.
*
* If there is no more data in the buffer, this will throw an assertion, so
* you're advised to check for existence of data using hasNext().
*
* @return the next value from the buffer
*/
OT next()
{
/* get<OT>() will assert if the offset points beyond the end of the buffer */
return iv_buffer.get<OT>(iv_offset++);
}
/**
* @brief Return true if there's more data to read
* @return true if there's more data to read
*/
bool hasNext()
{
return iv_offset < iv_buffer.getLength<OT>();
}
private:
fapi2::variable_buffer& iv_buffer;
uint32_t iv_offset;
};
//@}
} // namespace fapi2
#endif /* BUFFER_STREAM_H_ */
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