xisb.c revision 05b261ec 
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 <xf86Version.h>
45#include <xf86_OSproc.h>
46#include <xf86_OSlib.h>
47#include <xf86Xinput.h>
48#include "xisb.h"
49
50/*****************************************************************************
51 *	Local Headers
52 ****************************************************************************/
53
54/*****************************************************************************
55 *	Variables without includable headers
56 ****************************************************************************/
57
58/*****************************************************************************
59 *	Local Variables
60 ****************************************************************************/
61
62/*****************************************************************************
63 *	Function Definitions
64 ****************************************************************************/
65
66_X_EXPORT XISBuffer *
67XisbNew (int fd, ssize_t size)
68{
69	XISBuffer *b;
70
71	b = xalloc (sizeof (XISBuffer));
72	if (!b)
73		return (NULL);
74	b->buf = xalloc ((sizeof (unsigned char) * size));
75	if (!b->buf)
76	{
77		xfree (b);
78		return (NULL);
79	}
80
81	b->fd = fd;
82	b->trace = 0;
83	b->block_duration = 0;
84	b->current = 1;	/* force it to be past the end to trigger initial read */
85	b->end = 0;
86	b->buffer_size = size;
87	return (b);
88}
89
90_X_EXPORT void
91XisbFree (XISBuffer *b)
92{
93	xfree (b->buf);
94	xfree (b);
95}
96
97_X_EXPORT int
98XisbRead (XISBuffer *b)
99{
100	int ret;
101
102	if (b->current >= b->end)
103	{
104		if (b->block_duration >= 0)
105		{
106			if (xf86WaitForInput (b->fd, b->block_duration) < 1)
107				return (-1);
108		}
109		else
110		{
111			/*
112			 * automatically clear it so if XisbRead is called in a loop
113			 * the next call will make sure there is data with select and
114			 * thus prevent a blocking read
115			 */
116			b->block_duration = 0;
117		}
118
119		ret = xf86ReadSerial (b->fd, b->buf, b->buffer_size);
120		switch (ret)
121		{
122			case 0:
123				return (-1); /* timeout */
124			case -1:
125				return (-2); /* error */
126			default:
127				b->end = ret;
128				b->current = 0;
129				break;
130		}
131	}
132	if (b->trace)
133		ErrorF ("read 0x%02x (%c)\n", b->buf[b->current],
134			isprint(b->buf[b->current])?b->buf[b->current]:'.');
135
136	return (b->buf[b->current++]);
137}
138
139/* the only purpose of this function is to provide output tracing */
140_X_EXPORT ssize_t
141XisbWrite (XISBuffer *b, unsigned char *msg, ssize_t len)
142{
143    if (b->trace)
144    {
145        int i = 0;
146        for (i = 0; i < len; i++)
147            ErrorF ("\t\twrote 0x%02x (%c)\n", msg[i], msg[i]);
148    }
149    return (xf86WriteSerial (b->fd, msg, len));
150}
151
152/* turn tracing of this buffer on (1) or off (0) */
153_X_EXPORT void
154XisbTrace (XISBuffer *b, int trace)
155{
156	b->trace = trace;
157}
158
159/*
160 * specify a block_duration of -1 when you know the buffer's fd is ready to
161 * read. After a read, it is automatically set to 0 so that the next read
162 * will use check to select for data and prevent a block.
163 * It is the caller's responsibility to set the block_duration to -1 if it
164 * knows that there is data to read (because the main select loop triggered
165 * the read) and want's to avoid the unnecessary overhead of the select call
166 *
167 * a zero or positive block duration will cause the select to block for the
168 * give duration in usecs.
169 */
170
171_X_EXPORT void
172XisbBlockDuration (XISBuffer *b, int block_duration)
173{
174	b->block_duration = block_duration;
175}
176