3 fast inter-user-process single-reader/single-writer channels
4 using a modified version of jack ringbuffers and memory-mapped files.
6 This file is part of a program that implements a Software-Defined Radio.
8 Copyright (C) 2004 by Frank Brickle, AB2KT and Bob McGwier, N4HY
10 This program is free software; you can redistribute it and/or modify
11 it under the terms of the GNU General Public License as published by
12 the Free Software Foundation; either version 2 of the License, or
13 (at your option) any later version.
15 This program is distributed in the hope that it will be useful,
16 but WITHOUT ANY WARRANTY; without even the implied warranty of
17 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 GNU General Public License for more details.
20 You should have received a copy of the GNU General Public License
21 along with this program; if not, write to the Free Software
22 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
24 The authors can be reached by email at
32 The DTTS Microwave Society
40 putChan(Chan c, char *data, size_t size) {
41 return ringb_write(c->rb, data, size);
45 getChan(Chan c, char *data, size_t size) {
46 return ringb_read(c->rb, data, size);
50 putChan_nowait(Chan c, char *data, size_t size) {
51 if (ringb_write_space(c->rb) >= size) {
52 ringb_write(c->rb, data, size);
58 putChan_force(Chan c, char *data, size_t size) {
59 if (ringb_write_space(c->rb) >= size) {
60 ringb_write(c->rb, data, size);
64 return ringb_write(c->rb, data, size);
69 getChan_nowait(Chan c, char *data, size_t size) {
70 if (ringb_read_space(c->rb) >= size) {
71 ringb_read(c->rb, data, size);
77 resetChan(Chan c) { ringb_reset(c->rb); }
80 openChan(char *path, size_t want) {
81 Chan c = (Chan) safealloc(sizeof(ChanDesc), 1, "Chan header");
82 c->size.rib = sizeof(ringb_t);
83 c->size.buf = nblock2(want);
85 if ((c->file.desc = open(c->file.path, O_RDWR)) == -1) {
86 fprintf(stderr, "can't open Chan file %s\n", c->file.path);
89 c->size.tot = c->size.rib + c->size.buf;
90 if ((c->size.tru = fdsize(c->file.desc)) < c->size.tot) {
92 "Chan file %s is too small (%d) for required size (%s)\n",
93 c->file.path, c->size.tru, c->size.tot);
96 if (!(c->map.base = (char *) mmap(0,
98 PROT_READ | PROT_WRITE,
102 fprintf(stderr, "can't memory map %s for Chan\n",
106 if (!(c->rb = ringb_create(c->map.base, c->size.buf))) {
107 fprintf(stderr, "can't map RB for Chan\n");
117 munmap(c->map.base, c->size.tot);
118 safefree((char *) c);