GNU Radio C++ API
gri_wavfile.h
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1 /* -*- c++ -*- */
2 /*
3  * Copyright 2008 Free Software Foundation, Inc.
4  *
5  * This file is part of GNU Radio
6  *
7  * GNU Radio is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License as published by
9  * the Free Software Foundation; either version 3, or (at your option)
10  * any later version.
11  *
12  * GNU Radio is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15  * GNU General Public License for more details.
16  *
17  * You should have received a copy of the GNU General Public License
18  * along with GNU Radio; see the file COPYING. If not, write to
19  * the Free Software Foundation, Inc., 51 Franklin Street,
20  * Boston, MA 02110-1301, USA.
21  */
22 
23 // This file stores all the RIFF file type knowledge for the gr_wavfile_*
24 // blocks.
25 
26 #include <gr_core_api.h>
27 #include <cstdio>
28 
29 /*!
30  * \brief Read signal information from a given WAV file.
31  *
32  * \p fp File pointer to an opened, empty file.
33  * \p sample_rate Stores the sample rate [S/s]
34  * \p nchans Number of channels
35  * \p bytes_per_sample Bytes per sample, can either be 1 or 2 (corresponding to
36  * 8 or 16 bit samples, respectively)
37  * \p first_sample_pos Number of the first byte containing a sample. Use this
38  * with fseek() to jump from the end of the file to the first sample
39  * when in repeat mode.
40  * \p samples_per_chan Number of samples per channel
41  * \p normalize_fac The normalization factor with which you need to divide the
42  * integer values of the samples to get them within [-1;1]
43  * \p normalize_shift The value by which the sample values need to be shifted
44  * after normalization (reason being, 8-bit WAV files store samples as
45  * unsigned char and 16-bit as signed short int)
46  * \return True on a successful read, false if the file could not be read or is
47  * not a valid WAV file.
48  */
49 bool
50 gri_wavheader_parse(FILE *fp,
51  unsigned int &sample_rate,
52  int &nchans,
53  int &bytes_per_sample,
54  int &first_sample_pos,
55  unsigned int &samples_per_chan);
56 
57 
58 /*!
59  * \brief Read one sample from an open WAV file at the current position.
60  *
61  * Takes care of endianness.
62  */
63 short int
64 gri_wav_read_sample(FILE *fp, int bytes_per_sample);
65 
66 
67 /*!
68  * \brief Write a valid RIFF file header
69  *
70  * Note: Some header values are kept blank because they're usually not known
71  * a-priori (file and chunk lengths). Use gri_wavheader_complete() to fill
72  * these in.
73  */
74 bool
75 gri_wavheader_write(FILE *fp,
76  unsigned int sample_rate,
77  int nchans,
78  int bytes_per_sample);
79 
80 /*!
81  * \brief Write one sample to an open WAV file at the current position.
82  *
83  * Takes care of endianness.
84  */
85 void
86 gri_wav_write_sample(FILE *fp, short int sample, int bytes_per_sample);
87 
88 
89 /*!
90  * \brief Complete a WAV header
91  *
92  * Note: The stream position is changed during this function. If anything
93  * needs to be written to the WAV file after calling this function (which
94  * shouldn't happen), you need to fseek() to the end of the file (or
95  * whereever).
96  *
97  * \p fp File pointer to an open WAV file with a blank header
98  * \p byte_count Length of all samples written to the file in bytes.
99  */
100 bool
101 gri_wavheader_complete(FILE *fp, unsigned int byte_count);