libexplain  1.4.D001
libexplain/buffer/v4l2_fmtdesc.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_buf_type.h>
00026 #include <libexplain/buffer/v4l2_fmtdesc.h>
00027 #include <libexplain/buffer/v4l2_fmtdesc_flags.h>
00028 #include <libexplain/buffer/v4l2_pixel_format.h>
00029 #include <libexplain/buffer/pointer.h>
00030 #include <libexplain/is_efault.h>
00031 #include <libexplain/sizeof.h>
00032 
00033 
00034 #ifdef HAVE_LINUX_VIDEODEV2_H
00035 
00036 void
00037 explain_buffer_v4l2_fmtdesc(explain_string_buffer_t *sb,
00038     const struct v4l2_fmtdesc *data, int extra)
00039 {
00040     if (explain_is_efault_pointer(data, sizeof(*data)))
00041     {
00042         explain_buffer_pointer(sb, data);
00043         return;
00044     }
00045 
00046     explain_string_buffer_puts(sb, "{ index = ");
00047     explain_buffer_uint32_t(sb, data->index);
00048     explain_string_buffer_puts(sb, ", type = ");
00049     explain_buffer_v4l2_buf_type(sb, data->type);
00050     if (extra)
00051     {
00052         explain_string_buffer_puts(sb, ", flags = ");
00053         explain_buffer_v4l2_fmtdesc_flags(sb, data->flags);
00054         explain_string_buffer_puts(sb, ", description = ");
00055         explain_string_buffer_putsu_quoted_n(sb, data->description,
00056             sizeof(data->description));
00057         explain_string_buffer_puts(sb, ", pixelformat = ");
00058         explain_buffer_v4l2_pixel_format(sb, data->pixelformat);
00059         if (!explain_uint32_array_all_zero(data->reserved,
00060             SIZEOF(data->reserved)))
00061         {
00062             explain_string_buffer_puts(sb, ", reserved = ");
00063             explain_buffer_uint32_array(sb, data->reserved,
00064                 SIZEOF(data->reserved));
00065         }
00066     }
00067     explain_string_buffer_puts(sb, " }");
00068 }
00069 
00070 
00071 int
00072 explain_v4l2_fmtdesc_get_nformats(int fildes, int type)
00073 {
00074     int lo = 0;
00075     int hi = 200;
00076     for (;;)
00077     {
00078         int mid = (lo + hi) / 2;
00079         struct v4l2_fmtdesc fmtdesc;
00080         memset(&fmtdesc, 0, sizeof(fmtdesc));
00081         fmtdesc.index = mid;
00082         fmtdesc.type = type; /* NOT optional */
00083         if (ioctl(fildes, VIDIOC_ENUM_FMT, &fmtdesc) >= 0)
00084         {
00085             if (hi <= 0 && lo <= 0)
00086                 return -1;
00087             /* mid < nframes */
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 >= nframes */
00101             hi = mid - 1;
00102             if (lo >= hi)
00103                 return lo;
00104         }
00105     }
00106 }
00107 
00108 #endif
00109 
00110 /* vim: set ts=8 sw=4 et : */