libexplain  1.4.D001
libexplain/buffer/v4l2_dv_enum_preset.c
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00001 /*
00002  * libexplain - a library of system-call-specific strerror replacements
00003  * Copyright (C) 2011, 2013 Peter Miller
00004  *
00005  * This program is free software; you can redistribute it and/or modify
00006  * it under the terms of the GNU Lesser General Public License as
00007  * published by the Free Software Foundation; either version 3 of the
00008  * License, or (at your option) any later version.
00009  *
00010  * This program is distributed in the hope that it will be useful,
00011  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00012  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00013  * Lesser General Public License for more details.
00014  *
00015  * You should have received a copy of the GNU Lesser General Public License
00016  * along with this program. If not, see <http://www.gnu.org/licenses/>.
00017  */
00018 
00019 #include <libexplain/ac/errno.h>
00020 #include <libexplain/ac/linux/videodev2.h>
00021 #include <libexplain/ac/string.h>
00022 #include <libexplain/ac/sys/ioctl.h>
00023 
00024 #include <libexplain/buffer/int32_t.h>
00025 #include <libexplain/buffer/v4l2_dv_enum_preset.h>
00026 #include <libexplain/buffer/v4l2_dv_preset_value.h>
00027 #include <libexplain/buffer/pointer.h>
00028 #include <libexplain/is_efault.h>
00029 #include <libexplain/sizeof.h>
00030 
00031 
00032 #ifdef HAVE_LINUX_VIDEODEV2_H
00033 #ifdef VIDIOC_ENUM_DV_PRESETS
00034 
00035 void
00036 explain_buffer_v4l2_dv_enum_preset(explain_string_buffer_t *sb,
00037     const struct v4l2_dv_enum_preset *data, int extra)
00038 {
00039     if (explain_is_efault_pointer(data, sizeof(*data)))
00040     {
00041         explain_buffer_pointer(sb, data);
00042         return;
00043     }
00044 
00045     explain_string_buffer_puts(sb, "{ index = ");
00046     explain_buffer_uint32_t(sb, data->index);
00047     if (extra)
00048     {
00049         explain_string_buffer_puts(sb, ", preset = ");
00050         explain_buffer_v4l2_dv_preset_value(sb, data->preset);
00051         explain_string_buffer_puts(sb, ", name = ");
00052         explain_string_buffer_putsu_quoted_n(sb, data->name,
00053             sizeof(data->name));
00054         explain_string_buffer_puts(sb, ", width = ");
00055         explain_buffer_uint32_t(sb, data->width);
00056         explain_string_buffer_puts(sb, ", height = ");
00057         explain_buffer_uint32_t(sb, data->height);
00058         if (!explain_uint32_array_all_zero(data->reserved,
00059             SIZEOF(data->reserved)))
00060         {
00061             explain_string_buffer_puts(sb, ", reserved = ");
00062             explain_buffer_uint32_array(sb, data->reserved,
00063                 SIZEOF(data->reserved));
00064         }
00065     }
00066     explain_string_buffer_puts(sb, " }");
00067 }
00068 
00069 
00070 int
00071 explain_v4l2_dv_enum_preset_get_n(int fildes)
00072 {
00073     int lo = 0;
00074     int hi = 200;
00075     for (;;)
00076     {
00077         struct v4l2_dv_enum_preset qry;
00078         int             mid;
00079 
00080         mid = (lo + hi) / 2;
00081         memset(&qry, 0, sizeof(qry));
00082         qry.index = mid;
00083         if (ioctl(fildes, VIDIOC_ENUM_DV_PRESETS, &qry) >= 0)
00084         {
00085             if (hi <= 0 && lo <= 0)
00086                 return -1;
00087             /* mid < n */
00088             lo = mid + 1;
00089             if (lo > hi)
00090                 return lo;
00091         }
00092         else if (errno != EINVAL)
00093         {
00094             return -1;
00095         }
00096         else
00097         {
00098             if (hi <= 0 && lo <= 0)
00099                 return -1;
00100             /* mid >= n */
00101             hi = mid - 1;
00102             if (lo >= hi)
00103                 return lo;
00104         }
00105     }
00106 }
00107 
00108 #endif
00109 #endif
00110 
00111 /* vim: set ts=8 sw=4 et : */