rc4: Round up output buffer size.
[paraslash.git] / random_selector.c
1 /*
2 * Copyright (C) 2004-2007 Andre Noll <maan@systemlinux.org>
3 *
4 * Licensed under the GPL v2. For licencing details see COPYING.
5 */
6
7 /** \file random_selector.c An audio file selector which chooses files by random */
8
9 #include <sys/time.h> /* gettimeofday */
10 #include "server.cmdline.h"
11 #include "server.h"
12 #include "afs_common.h"
13 #include "error.h"
14 #include "net.h"
15 #include "string.h"
16 #include "random_selector_command_list.h"
17
18 extern struct misc_meta_data *mmd;
19
20 static unsigned int num_audio_files, audio_file_count;
21 static char **audio_file_list;
22
23 static int count_audio_files(__a_unused const char *dir, __a_unused const char *name)
24 {
25 num_audio_files++;
26 return 1;
27 }
28
29 static int remember_file(const char *dir, const char *name)
30 {
31 if (audio_file_count < num_audio_files) {
32 audio_file_list[audio_file_count] =
33 make_message("%s/%s", dir, name);
34 audio_file_count++;
35 }
36 return 1;
37 }
38
39 int com_random_info(int fd, __a_unused int argc, __a_unused char *argv[])
40 {
41 return send_buffer(fd, "Don't use for huge directories as it is "
42 "very inefficient in this case.\n");
43 }
44
45 /*
46 * Load a list of all audio files into memory and chose num of them randomly.
47 * Called by server to determine next audio file to be streamed.
48 */
49 static char **random_get_audio_file_list(unsigned int num)
50 {
51 int i, ret;
52 unsigned int len;
53 char **ret_list = NULL; /* what we are going to return */
54
55 audio_file_list = NULL;
56 num_audio_files = 0;
57 /* first run, just count all audio files. dopey */
58 ret = find_audio_files(conf.random_dir_arg, count_audio_files);
59 if (ret < 0)
60 goto out;
61 ret = -E_NOTHING_FOUND;
62 if (!num_audio_files)
63 goto out;
64 /* yeah, that doesn't scale, also dopey */
65 audio_file_list = para_malloc(num_audio_files * sizeof(char *));
66 audio_file_count = 0;
67 /* second run (hot dentry cache, hopefully), fill audio_file_list */
68 ret = find_audio_files(conf.random_dir_arg, remember_file);
69 if (ret < 0)
70 goto out;
71 /* careful, files might got deleted underneath */
72 num_audio_files = audio_file_count; /* can only decrease */
73 len = PARA_MIN(num, num_audio_files);
74 ret = -E_NOTHING_FOUND;
75 if (!len) /* nothing found, return NULL */
76 goto out;
77 /* success, return NULL-terminated list */
78 ret_list = para_calloc((len + 1) * sizeof(char *));
79 for (i = 0; i < len; i++) { /* choose randomly */
80 int r = (int) ((num_audio_files + 0.0) * (rand()
81 / (RAND_MAX + 1.0)));
82 ret_list[i] = para_strdup(audio_file_list[r]);
83 }
84 ret = 1;
85 out:
86 if (audio_file_list) {
87 for (i = 0; i < num_audio_files; i++)
88 free(audio_file_list[i]);
89 free(audio_file_list);
90 }
91 if (ret > 0) {
92 } else
93 sprintf(mmd->selector_info, "dbinfo1:%s\n", PARA_STRERROR(-ret));
94 return ret_list;
95 }
96
97 static void random_update_audio_file(char *audio_file)
98 {
99 char *dn = para_dirname(audio_file);
100 snprintf(mmd->selector_info, MMD_INFO_SIZE - 1,
101 "dbinfo1:current dir: %s\n"
102 "dbinfo2:random_dir: %s\n"
103 "dbinfo3:%d files available\n",
104 dn, conf.random_dir_arg, num_audio_files);
105 free(dn);
106 mmd->selector_info[MMD_INFO_SIZE - 1] = '\0';
107 }
108 static void random_shutdown(void)
109 {
110 }
111
112 /**
113 * the init function for the random audio file selector
114 *
115 * \param s pointer ro the struct to iniitalize
116 *
117 * Init all function pointers of \a s, init the info text and seed the PRNG.
118 *
119 * \sa struct audio_file_selector, misc_meta_data::selector_info, mysql.c
120 */
121 int random_selector_init(struct audio_file_selector *s)
122 {
123 struct timeval now;
124 unsigned int seed;
125
126 PARA_INFO_LOG("%s", "registering random handlers ;)\n");
127 gettimeofday(&now, NULL);
128 seed = now.tv_usec;
129 srand(seed);
130 s->cmd_list = random_selector_cmds;
131 s->get_audio_file_list = random_get_audio_file_list;
132 s->shutdown = random_shutdown;
133 s->update_audio_file = random_update_audio_file;
134 snprintf(mmd->selector_info, MMD_INFO_SIZE - 1,
135 "dbinfo1: Welcome to the random selector\n"
136 "dbinfo2: random_dir: %s\n", conf.random_dir_arg);
137 mmd->selector_info[MMD_INFO_SIZE - 1] = '\0';
138 return 1;
139 }