1 /* This program is licensed under the GNU Library General Public License,
2 * version 2, a copy of which is included with this program (LICENCE.LGPL).
4 * (c) 2002 Simon Hosie <gumboot@clear.net.nz>
10 * 'Digital Filters', third edition, by R. W. Hamming ISBN 0-486-65088-X
13 * 2002-05-31 ready for the world (or some small section thereof)
17 * zero-crossing clipping in coefficient table
20 #ifndef _RESAMPLE_H_INCLUDED
21 #define _RESAMPLE_H_INCLUDED
27 unsigned int channels, infreq, outfreq, taps;
39 RES_GAIN, /* (double)1.0 */
40 RES_CUTOFF, /* (double)0.80 */
41 RES_TAPS, /* (int)45 */
42 RES_BETA /* (double)16.0 */
45 int res_init(res_state *state, int channels, int outfreq, int infreq, res_parameter op1, ...);
47 * Configure *state to manage a data stream with the specified parameters. The
48 * string 'params' is currently unspecified, but will configure the parameters
51 * This function allocates memory, and requires that res_clear() be called when
52 * the buffer is no longer needed.
55 * All counts/lengths used in the following functions consider only the data in
56 * a single channel, and in numbers of samples rather than bytes, even though
57 * functionality will be mirrored across as many channels as specified here.
61 int res_push_max_input(res_state const *state, size_t maxoutput);
63 * Returns the maximum number of input elements that may be provided without
64 * risk of flooding an output buffer of size maxoutput. maxoutput is
65 * specified in counts of elements, NOT in bytes.
69 int res_push_check(res_state const *state, size_t srclen);
71 * Returns the number of elements that will be returned if the given srclen
72 * is used in the next call to res_push().
76 int res_push(res_state *state, SAMPLE **dstlist, SAMPLE const **srclist, size_t srclen);
77 int res_push_interleaved(res_state *state, SAMPLE *dest, SAMPLE const *source, size_t srclen);
79 * Pushes srclen samples into the front end of the filter, and returns the
80 * number of resulting samples.
82 * res_push(): srclist and dstlist point to lists of pointers, each of which
83 * indicates the beginning of a list of samples.
85 * res_push_interleaved(): source and dest point to the beginning of a list of
86 * interleaved samples.
90 int res_drain(res_state *state, SAMPLE **dstlist);
91 int res_drain_interleaved(res_state *state, SAMPLE *dest);
93 * Recover the remaining elements by flushing the internal pool with 0 values,
94 * and storing the resulting samples.
96 * After either of these functions are called, *state should only re-used in a
97 * final call to res_clear().
101 void res_clear(res_state *state);
103 * Free allocated buffers, etc.