libexplain  1.4.D001
libexplain/iocontrol/vidioc_g_ctrl.c
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00001 /*
00002  * libexplain - a library of system-call-specific strerror replacements
00003  * Copyright (C) 2011, 2013 Peter Miller
00004  * Written by Peter Miller <pmiller@opensource.org.au>
00005  *
00006  * This program is free software; you can redistribute it and/or modify it
00007  * under the terms of the GNU Lesser General Public License as published by
00008  * the Free Software Foundation; either version 3 of the License, or (at your
00009  * option) any later version.
00010  *
00011  * This program is distributed in the hope that it will be useful, but WITHOUT
00012  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
00013  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
00014  * License for more details.
00015  *
00016  * You should have received a copy of the GNU Lesser General Public License
00017  * along with this program. If not, see <http://www.gnu.org/licenses/>.
00018  */
00019 
00020 #include <libexplain/ac/errno.h>
00021 #include <libexplain/ac/linux/videodev2.h>
00022 #include <libexplain/ac/sys/ioctl.h>
00023 
00024 #include <libexplain/buffer/einval.h>
00025 #include <libexplain/buffer/enotsup.h>
00026 #include <libexplain/buffer/is_the_null_pointer.h>
00027 #include <libexplain/buffer/v4l2_control.h>
00028 #include <libexplain/iocontrol/generic.h>
00029 #include <libexplain/iocontrol/vidioc_g_ctrl.h>
00030 
00031 #ifdef VIDIOC_G_CTRL
00032 
00033 
00034 static void
00035 print_data(const explain_iocontrol_t *p, explain_string_buffer_t *sb,
00036     int errnum, int fildes, int request, const void *data)
00037 {
00038     (void)p;
00039     (void)errnum;
00040     (void)request;
00041     explain_buffer_v4l2_control(sb, data, 0, fildes);
00042 }
00043 
00044 
00045 static void
00046 print_explanation(const explain_iocontrol_t *p, explain_string_buffer_t *sb,
00047     int errnum, int fildes, int request, const void *data)
00048 {
00049     switch (errnum)
00050     {
00051     case EIO:
00052         explain_string_buffer_puts
00053         (
00054             sb,
00055             /* FIXME: i18n */
00056             "reading a device register failed"
00057         );
00058         return;
00059 
00060     case EINVAL:
00061         if (!data)
00062         {
00063             explain_buffer_is_the_null_pointer(sb, "data");
00064             return;
00065         }
00066 
00067         switch (explain_v4l2_control_check_id(fildes, data))
00068         {
00069         case explain_v4l2_control_check_id_no_idea:
00070         default:
00071             goto best_guess;
00072 
00073         case explain_v4l2_control_check_id_notsup:
00074             explain_buffer_enotsup_device(sb, "data->id");
00075             break;
00076 
00077         case explain_v4l2_control_check_id_nosuch:
00078             best_guess:
00079             explain_buffer_einval_vague(sb, "data->id");
00080             break;
00081 
00082         case explain_v4l2_control_check_id_ok:
00083             goto generic;
00084         }
00085         break;
00086 
00087     default:
00088         generic:
00089         explain_iocontrol_generic_print_explanation
00090         (
00091             p,
00092             sb,
00093             errnum,
00094             fildes,
00095             request,
00096             data
00097         );
00098         break;
00099     }
00100 }
00101 
00102 
00103 static void
00104 print_data_returned(const explain_iocontrol_t *p, explain_string_buffer_t *sb,
00105     int errnum, int fildes, int request, const void *data)
00106 {
00107     (void)p;
00108     (void)errnum;
00109     (void)request;
00110     explain_buffer_v4l2_control(sb, data, 1, fildes);
00111 }
00112 
00113 
00114 const explain_iocontrol_t explain_iocontrol_vidioc_g_ctrl =
00115 {
00116     "VIDIOC_G_CTRL", /* name */
00117     VIDIOC_G_CTRL, /* value */
00118     0, /* disambiguate */
00119     0, /* print_name */
00120     print_data,
00121     print_explanation,
00122     print_data_returned,
00123     sizeof(struct v4l2_control), /* data_size */
00124     "struct v4l2_control *", /* data_type */
00125     0, /* flags */
00126     __FILE__,
00127     __LINE__,
00128 };
00129 
00130 #else /* ndef VIDIOC_G_CTRL */
00131 
00132 const explain_iocontrol_t explain_iocontrol_vidioc_g_ctrl =
00133 {
00134     0, /* name */
00135     0, /* value */
00136     0, /* disambiguate */
00137     0, /* print_name */
00138     0, /* print_data */
00139     0, /* print_explanation */
00140     0, /* print_data_returned */
00141     0, /* data_size */
00142     0, /* data_type */
00143     0, /* flags */
00144     __FILE__,
00145     __LINE__,
00146 };
00147 
00148 #endif /* VIDIOC_G_CTRL */
00149 
00150 
00151 /* vim: set ts=8 sw=4 et : */