xisb.c revision 6747b715 
1/*
2 * Copyright (c) 1997  Metro Link Incorporated
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining a
5 * copy of this software and associated documentation files (the "Software"),
6 * to deal in the Software without restriction, including without limitation
7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8 * and/or sell copies of the Software, and to permit persons to whom the
9 * Software is furnished to do so, subject to the following conditions:
10 *
11 * The above copyright notice and this permission notice shall be included in
12 * all copies or substantial portions of the Software.
13 *
14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
15 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
16 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
17 * THE X CONSORTIUM BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
18 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF
19 * OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
20 * SOFTWARE.
21 *
22 * Except as contained in this notice, the name of the Metro Link shall not be
23 * used in advertising or otherwise to promote the sale, use or other dealings
24 * in this Software without prior written authorization from Metro Link.
25 *
26 */
27
28/*
29	X Input Serial Buffer routines for use in any XInput driver that accesses
30	a serial device.
31*/
32
33
34/*****************************************************************************
35 *	Standard Headers
36 ****************************************************************************/
37
38#ifdef HAVE_XORG_CONFIG_H
39#include <xorg-config.h>
40#endif
41
42#include <misc.h>
43#include <xf86.h>
44#include <xf86_OSproc.h>
45#include <xf86_OSlib.h>
46#include <xf86Xinput.h>
47#include "xisb.h"
48
49/*****************************************************************************
50 *	Local Headers
51 ****************************************************************************/
52
53/*****************************************************************************
54 *	Variables without includable headers
55 ****************************************************************************/
56
57/*****************************************************************************
58 *	Local Variables
59 ****************************************************************************/
60
61/*****************************************************************************
62 *	Function Definitions
63 ****************************************************************************/
64
65XISBuffer *
66XisbNew (int fd, ssize_t size)
67{
68	XISBuffer *b;
69
70	b = malloc(sizeof (XISBuffer));
71	if (!b)
72		return NULL;
73	b->buf = malloc((sizeof (unsigned char) * size));
74	if (!b->buf)
75	{
76		free(b);
77		return NULL;
78	}
79
80	b->fd = fd;
81	b->trace = 0;
82	b->block_duration = 0;
83	b->current = 1;	/* force it to be past the end to trigger initial read */
84	b->end = 0;
85	b->buffer_size = size;
86	return b;
87}
88
89void
90XisbFree (XISBuffer *b)
91{
92	free(b->buf);
93	free(b);
94}
95
96int
97XisbRead (XISBuffer *b)
98{
99	int ret;
100
101	if (b->current >= b->end)
102	{
103		if (b->block_duration >= 0)
104		{
105			if (xf86WaitForInput (b->fd, b->block_duration) < 1)
106				return -1;
107		}
108		else
109		{
110			/*
111			 * automatically clear it so if XisbRead is called in a loop
112			 * the next call will make sure there is data with select and
113			 * thus prevent a blocking read
114			 */
115			b->block_duration = 0;
116		}
117
118		ret = xf86ReadSerial (b->fd, b->buf, b->buffer_size);
119		switch (ret)
120		{
121			case 0:
122				return -1; /* timeout */
123			case -1:
124				return -2; /* error */
125			default:
126				b->end = ret;
127				b->current = 0;
128				break;
129		}
130	}
131	if (b->trace)
132		ErrorF ("read 0x%02x (%c)\n", b->buf[b->current],
133			isprint(b->buf[b->current])?b->buf[b->current]:'.');
134
135	return b->buf[b->current++];
136}
137
138/* the only purpose of this function is to provide output tracing */
139ssize_t
140XisbWrite (XISBuffer *b, unsigned char *msg, ssize_t len)
141{
142    if (b->trace)
143    {
144        int i = 0;
145        for (i = 0; i < len; i++)
146            ErrorF ("\t\twrote 0x%02x (%c)\n", msg[i], msg[i]);
147    }
148    return (xf86WriteSerial (b->fd, msg, len));
149}
150
151/* turn tracing of this buffer on (1) or off (0) */
152void
153XisbTrace (XISBuffer *b, int trace)
154{
155	b->trace = trace;
156}
157
158/*
159 * specify a block_duration of -1 when you know the buffer's fd is ready to
160 * read. After a read, it is automatically set to 0 so that the next read
161 * will use check to select for data and prevent a block.
162 * It is the caller's responsibility to set the block_duration to -1 if it
163 * knows that there is data to read (because the main select loop triggered
164 * the read) and want's to avoid the unnecessary overhead of the select call
165 *
166 * a zero or positive block duration will cause the select to block for the
167 * give duration in usecs.
168 */
169
170void
171XisbBlockDuration (XISBuffer *b, int block_duration)
172{
173	b->block_duration = block_duration;
174}
175