Rename random_dbtool.c to random_selector.c

[paraslash.git] / random_selector.c

diff --git a/random_selector.c b/random_selector.c
new file mode 100644 (file)
index 0000000..43cddb4
--- /dev/null
+++ b/random_selector.c
@@ -0,0 +1,150 @@
+/*
+ * Copyright (C) 2004-2006 Andre Noll <maan@systemlinux.org>
+ *
+ *     This program is free software; you can redistribute it and/or modify
+ *     it under the terms of the GNU General Public License as published by
+ *     the Free Software Foundation; either version 2 of the License, or
+ *     (at your option) any later version.
+ *
+ *     This program 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 General Public License for more details.
+ *
+ *     You should have received a copy of the GNU General Public License
+ *     along with this program; if not, write to the Free Software
+ *     Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111, USA.
+ */
+
+/** \file random_selector.c An audio file selector which chooses files by random */
+
+#include <sys/time.h> /* gettimeofday */
+#include "server.cmdline.h"
+#include "server.h"
+#include "db.h"
+#include "error.h"
+#include "net.h"
+#include "string.h"
+
+static int com_random_info(int, int, char **);
+extern struct gengetopt_args_info conf;
+extern struct misc_meta_data *mmd;
+
+static unsigned int num_audio_files, audio_file_count;
+static char **audio_file_list;
+
+static int count_audio_files(__unused const char *dir, __unused const char *name)
+{
+       num_audio_files++;
+       return 1;
+}
+
+static int remember_file(const char *dir, const char *name)
+{
+       if (audio_file_count >= num_audio_files)
+               return -E_FILE_COUNT;
+       audio_file_list[audio_file_count] = make_message("%s/%s", dir, name);
+       audio_file_count++;
+       return 1;
+}
+
+/* array of commands that are supported by this selector */
+static struct server_command cmds[] = {
+{
+.name = "random_info",
+.handler = com_random_info,
+.perms = 0,
+.description = "about the random database tool",
+.synopsis = "random_info",
+.help =
+
+"Select a random file under the given directory"
+}, {
+.name = NULL,
+}
+};
+
+static int com_random_info(int fd, __unused int argc, __unused char *argv[])
+{
+       return send_buffer(fd, "Don't use for huge directories as it is "
+               "very inefficient in this case.\n");
+}
+
+/*
+ * Load a list of all audio files into memory and chose num of them randomly.
+ * Called by server to determine next audio file to be streamed.
+ */
+static char **random_get_audio_file_list(unsigned int num)
+{
+       int i, ret;
+       unsigned int len;
+       char **ret_list = NULL; /* what we are going to return */
+
+       audio_file_list = NULL;
+       num_audio_files = 0;
+       /* first run, just count all audio files. dopey */
+       ret = find_audio_files(conf.random_dir_arg, count_audio_files);
+       if (ret < 0)
+               goto out;
+       ret = -E_NOTHING_FOUND;
+       if (!num_audio_files)
+               goto out;
+       /* yeah, that doesn't scale, also dopey */
+       audio_file_list = para_malloc(num_audio_files * sizeof(char *));
+       audio_file_count = 0;
+       /* second run (hot dentry cache, hopefully), fill audio_file_list */
+       ret = find_audio_files(conf.random_dir_arg, remember_file);
+       if (ret < 0)
+               goto out;
+       /* careful, files might got deleted underneath */
+       num_audio_files = audio_file_count; /* can only decrease */
+       len = MIN(num, num_audio_files);
+       ret = -E_NOTHING_FOUND;
+       if (!len) /* nothing found, return NULL */
+               goto out;
+       /* success, return NULL-terminated list */
+       ret_list = para_calloc((len + 1) * sizeof(char *));
+       for (i = 0; i < len; i++) { /* choose randomly */
+               int r = (int) ((num_audio_files + 0.0) * (rand()
+                       / (RAND_MAX + 1.0)));
+               ret_list[i] = para_strdup(audio_file_list[r]);
+       }
+out:
+       if (audio_file_list) {
+               for (i = 0; i < num_audio_files; i++)
+                       free(audio_file_list[i]);
+               free(audio_file_list);
+       }
+//     if (ret < 0)
+//             PARA_ERROR_LOG("%s\n", PARA_STRERROR(-ret));
+       return ret_list;
+}
+
+static void random_shutdown(void)
+{
+}
+
+/** random's (constant) database info text */
+#define DBINFO "dbinfo1:database info? You're kidding. I'm still dopey!\ndbinfo2:\ndbinfo3:\n"
+
+/**
+ *  the init function for the random database tool
+ *
+ * Init all function pointers of \a db, init the dbinfo text and seed the
+ * PRNG.
+ *
+ * \sa struct audio_file_selector, misc_meta_data::dbinfo, mysql.c
+ */
+int random_selector_init(struct audio_file_selector *db)
+{
+       struct timeval now;
+
+       PARA_INFO_LOG("%s", "registering random handlers ;)\n");
+       sprintf(mmd->dbinfo, DBINFO);
+       gettimeofday(&now, NULL);
+       srand(now.tv_usec);
+       db->cmd_list = cmds;
+       db->get_audio_file_list = random_get_audio_file_list;
+       db->shutdown = random_shutdown;
+       return 1;
+}