pack_k_bits.h

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/* -*- c++ -*- */
/*
 * Copyright 2014 Free Software Foundation, Inc.
 *
 * This file is part of GNU Radio
 *
 * SPDX-License-Identifier: GPL-3.0-or-later
 *
 */
 
#ifndef INCLUDED_GR_BLOCKS_PACK_K_BITS_H
#define INCLUDED_GR_BLOCKS_PACK_K_BITS_H
 
#include <gnuradio/blocks/api.h>
 
namespace gr {
namespace blocks {
namespace kernel {
 
/*!
 * \brief Converts a vector of bytes with 1 bit in the LSB to a
 * byte with k relevant bits.
 *
 * Example:
 * k = 4
 * in = [0,1,0,1, 0x81,0x00,0x00,0x00]
 * out = [0x05, 0x08]
 *
 * k = 8
 * in = [1,1,1,1, 0,1,0,1, 0,0,0,0, 1,0,0,0]
 * out = [0xf5, 0x08]
 * \ingroup byte_operators_blk
 */
class BLOCKS_API pack_k_bits
{
public:
    /*!
     * \brief Make a pack_k_bits object.
     * \param k number of bits to be packed.
     */
    pack_k_bits(unsigned k);
    ~pack_k_bits();
 
    /*!
     * \brief Perform the packing.
     *
     * This block performs no bounds checking. It assumes that the
     * input, \p in, has of length k*nbytes and that the output
     * vector, \p out, has \p nbytes available for writing.
     *
     * \param bytes output vector (k-bits per byte) of the unpacked data
     * \param bits The input vector of bits to pack
     * \param nbytes The number of output bytes
     */
    void pack(unsigned char* bytes, const unsigned char* bits, int nbytes) const;
 
    /*!
     * Same as pack() but reverses the bits.
     */
    void pack_rev(unsigned char* bytes, const unsigned char* bits, int nbytes) const;
 
    int k() const;
 
private:
    unsigned d_k;
};
 
} /* namespace kernel */
} /* namespace blocks */
} /* namespace gr */
 
#endif /* INCLUDED_GR_BLOCKS_PACK_K_BITS_H */