tools: add a tool for enumerating/printing AVOptions in texinfo format

(cherry picked from commit e103cb3e9513949858ccf0ec44c5151239d397e9)
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

tools/enum_options.c

+/*
+ * Copyright (c) 2011 Anton Khirnov
+ *
+ * This file is part of Libav.
+ *
+ * Libav is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * Libav is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/*
+ * enumerate avoptions and format them in texinfo format
+ */
+
+#include <string.h>
+
+#include "libavformat/avformat.h"
+#include "libavcodec/avcodec.h"
+#include "libavutil/log.h"
+#include "libavutil/opt.h"
+
+static void print_usage(void)
+{
+    fprintf(stderr, "Usage: enum_options type\n"
+            "type: format codec\n");
+    exit(1);
+}
+
+static void print_option(const AVClass *class, const AVOption *o)
+{
+    printf("@item -%s @var{", o->name);
+    switch (o->type) {
+    case FF_OPT_TYPE_BINARY:   printf("hexadecimal string"); break;
+    case FF_OPT_TYPE_STRING:   printf("string");             break;
+    case FF_OPT_TYPE_INT:
+    case FF_OPT_TYPE_INT64:    printf("integer");            break;
+    case FF_OPT_TYPE_FLOAT:
+    case FF_OPT_TYPE_DOUBLE:   printf("float");              break;
+    case FF_OPT_TYPE_RATIONAL: printf("rational number");    break;
+    case FF_OPT_TYPE_FLAGS:    printf("flags");              break;
+    default:                   printf("value");              break;
+    }
+    printf("} (@emph{");
+
+    if (o->flags & AV_OPT_FLAG_ENCODING_PARAM) {
+        printf("input");
+        if (o->flags & AV_OPT_FLAG_ENCODING_PARAM)
+            printf("/");
+    }
+    if (o->flags & AV_OPT_FLAG_ENCODING_PARAM)
+        printf("output");
+
+    printf("})\n");
+    if (o->help)
+        printf("%s\n", o->help);
+
+    if (o->unit) {
+        const AVOption *u = NULL;
+        printf("\nPossible values:\n@table @samp\n");
+
+        while ((u = av_next_option(&class, u)))
+            if (u->type == FF_OPT_TYPE_CONST && u->unit && !strcmp(u->unit, o->unit))
+                printf("@item %s\n%s\n", u->name, u->help ? u->help : "");
+        printf("@end table\n");
+    }
+}
+
+static void show_opts(const AVClass *class)
+{
+    const AVOption *o = NULL;
+
+    printf("@table @option\n");
+    while ((o = av_next_option(&class, o)))
+        if (o->type != FF_OPT_TYPE_CONST)
+            print_option(class, o);
+    printf("@end table\n");
+}
+
+static void show_format_opts(void)
+{
+    AVInputFormat *iformat = NULL;
+    AVOutputFormat *oformat = NULL;
+
+    printf("@section Generic format AVOptions\n");
+    show_opts(avformat_get_class());
+
+    printf("@section Format-specific AVOptions\n");
+    while ((iformat = av_iformat_next(iformat))) {
+        if (!iformat->priv_class)
+            continue;
+        printf("@subsection %s AVOptions\n", iformat->priv_class->class_name);
+        show_opts(iformat->priv_class);
+    }
+    while ((oformat = av_oformat_next(oformat))) {
+        if (!oformat->priv_class)
+            continue;
+        printf("@subsection %s AVOptions\n", oformat->priv_class->class_name);
+        show_opts(oformat->priv_class);
+    }
+}
+
+static void show_codec_opts(void)
+{
+    AVCodec *c = NULL;
+
+    printf("@section Generic codec AVOptions\n");
+    show_opts(avcodec_get_class());
+
+    printf("@section Codec-specific AVOptions\n");
+    while ((c = av_codec_next(c))) {
+        if (!c->priv_class)
+            continue;
+        printf("@subsection %s AVOptions\n", c->priv_class->class_name);
+        show_opts(c->priv_class);
+    }
+}
+
+int main(int argc, char **argv)
+{
+    if (argc < 2)
+        print_usage();
+
+    av_register_all();
+
+    if (!strcmp(argv[1], "format"))
+        show_format_opts();
+    else if (!strcmp(argv[1], "codec"))
+        show_codec_opts();
+    else
+        print_usage();
+
+    return 0;
+}