gri_wavfile.h

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/* -*- c++ -*- */
/*
 * Copyright 2008 Free Software Foundation, Inc.
 *
 * This file is part of GNU Radio
 *
 * GNU Radio is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3, or (at your option)
 * any later version.
 *
 * GNU Radio is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with GNU Radio; see the file COPYING.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street,
 * Boston, MA 02110-1301, USA.
 */

// This file stores all the RIFF file type knowledge for the gr_wavfile_*
// blocks.

#include <cstdio>

/*!
 * \brief Read signal information from a given WAV file.
 *
 * \p fp File pointer to an opened, empty file.
 * \p sample_rate Stores the sample rate [S/s]
 * \p nchans      Number of channels
 * \p bytes_per_sample Bytes per sample, can either be 1 or 2 (corresponding to
 *         8 or 16 bit samples, respectively)
 * \p first_sample_pos Number of the first byte containing a sample. Use this
 *         with fseek() to jump from the end of the file to the first sample
 *         when in repeat mode.
 * \p samples_per_chan Number of samples per channel
 * \p normalize_fac The normalization factor with which you need to divide the
 *         integer values of the samples to get them within [-1;1]
 * \p normalize_shift The value by which the sample values need to be shifted
 *         after normalization (reason being, 8-bit WAV files store samples as
 *         unsigned char and 16-bit as signed short int)
 * \return True on a successful read, false if the file could not be read or is
 *         not a valid WAV file.
 */
bool
gri_wavheader_parse(FILE *fp,
                    unsigned int &sample_rate,
                    int &nchans,
                    int &bytes_per_sample,
                    int &first_sample_pos,
                    unsigned int &samples_per_chan);


/*!
 * \brief Read one sample from an open WAV file at the current position.
 *
 * Takes care of endianness.
 */
short int
gri_wav_read_sample(FILE *fp, int bytes_per_sample);


/*!
 * \brief Write a valid RIFF file header
 *
 * Note: Some header values are kept blank because they're usually not known
 * a-priori (file and chunk lengths). Use gri_wavheader_complete() to fill
 * these in.
 */
bool
gri_wavheader_write(FILE *fp,
                 unsigned int sample_rate,
                 int nchans,
                 int bytes_per_sample);

/*!
 * \brief Write one sample to an open WAV file at the current position.
 *
 * Takes care of endianness.
 */
void
gri_wav_write_sample(FILE *fp, short int sample, int bytes_per_sample);


/*!
 * \brief Complete a WAV header
 *
 * Note: The stream position is changed during this function. If anything
 * needs to be written to the WAV file after calling this function (which
 * shouldn't happen), you  need to fseek() to the end of the file (or 
 * whereever).
 *
 * \p fp File pointer to an open WAV file with a blank header
 * \p byte_count Length of all samples written to the file in bytes.
 */
bool
gri_wavheader_complete(FILE *fp, unsigned int byte_count);