crypt.c: Combine load_key() and get_private_key().
[paraslash.git] / filter_common.c
1 /*
2 * Copyright (C) 2005 Andre Noll <maan@tuebingen.mpg.de>
3 *
4 * Licensed under the GPL v2. For licencing details see COPYING.
5 */
6
7 /** \file filter_common.c Common helper functions for filter input/output. */
8
9 #include <regex.h>
10 #include <sys/types.h>
11
12 #include "para.h"
13 #include "list.h"
14 #include "sched.h"
15 #include "fd.h"
16 #include "ggo.h"
17 #include "buffer_tree.h"
18 #include "filter.h"
19 #include "error.h"
20 #include "string.h"
21
22 /** Iterate over the array of supported filters. */
23 #define FOR_EACH_SUPPORTED_FILTER(j) for (j = 0; j < NUM_SUPPORTED_FILTERS; j++)
24
25 /** The array of supported filters. */
26 static struct filter filters[NUM_SUPPORTED_FILTERS] = {FILTER_ARRAY};
27
28 /**
29 * Obtain a reference to a filter structure.
30 *
31 * \param filter_num Between zero and NUM_SUPPORTED_FILTERS, inclusively.
32 *
33 * \return Pointer to the filter identified by the given filter number.
34 *
35 * It is a fatal error if the given number is out of range. In this case
36 * the function aborts.
37 */
38 const struct filter *filter_get(int filter_num)
39 {
40 assert(filter_num >= 0);
41 assert(filter_num < NUM_SUPPORTED_FILTERS);
42 return filters + filter_num;
43 }
44
45 /**
46 * Call the init function of each supported filter.
47 * \sa filter::init
48 */
49 void filter_init(void)
50 {
51 int i;
52
53 FOR_EACH_SUPPORTED_FILTER(i)
54 filter_get(i)->init((struct filter *)filter_get(i));
55 }
56
57 /*
58 * If the filter has a command line parser and options is not NULL, run it.
59 * Returns filter_num on success, negative on errors
60 */
61 static int parse_filter_args(int filter_num, const char *options, void **conf)
62 {
63 const struct filter *f = filter_get(filter_num);
64 int ret, argc;
65 char **argv;
66
67 if (!f->parse_config)
68 return strlen(options)? -E_BAD_FILTER_OPTIONS : filter_num;
69 argc = create_shifted_argv(options, " \t", &argv);
70 if (argc < 0)
71 return -E_BAD_FILTER_OPTIONS;
72 argv[0] = para_strdup(f->name);
73 ret = f->parse_config(argc, argv, conf);
74 free_argv(argv);
75 return ret < 0? ret : filter_num;
76 }
77
78 /**
79 * Check the filter command line options.
80 *
81 * \param fa The filter argument.
82 * \param conf Points to the filter configuration upon successful return.
83 *
84 * Check if the given filter argument starts with the name of a supported
85 * filter, optionally followed by options for this filter. If yes, call the
86 * command line parser of that filter.
87 *
88 * \return On success, the number of the filter is returned and \a conf
89 * is initialized to point to the filter configuration determined by \a fa.
90 * On errors, a negative value is returned.
91 *
92 * Note: If \a fa specifies a filter that has no command line parser success is
93 * returned, and \a conf is initialized to \p NULL.
94 *
95 * \sa filter::parse_config
96 */
97 int check_filter_arg(const char *fa, void **conf)
98 {
99 int j;
100
101 *conf = NULL;
102 // PARA_DEBUG_LOG("arg: %s\n", fa);
103 FOR_EACH_SUPPORTED_FILTER(j) {
104 const char *name = filter_get(j)->name;
105 size_t len = strlen(name);
106 char c;
107 if (strlen(fa) < len)
108 continue;
109 if (strncmp(name, fa, len))
110 continue;
111 c = fa[len];
112 if (c && c != ' ')
113 continue;
114 if (c && !filter_get(j)->parse_config)
115 return -E_BAD_FILTER_OPTIONS;
116 return parse_filter_args(j, c? fa + len + 1 :
117 fa + strlen(fa), conf);
118 }
119 return -E_UNSUPPORTED_FILTER;
120 }
121
122 /**
123 * Print help text of each filter to stdout.
124 *
125 * \param flags Passed to \ref ggo_print_help().
126 */
127 void print_filter_helps(unsigned flags)
128 {
129 int i, num = 0;
130
131 printf_or_die("\nAvailable filters: ");
132 FOR_EACH_SUPPORTED_FILTER(i) {
133 if (num > 50) {
134 printf_or_die("\n ");
135 num = 0;
136 }
137 num += printf_or_die("%s%s", i? " " : "", filter_get(i)->name);
138 }
139 printf_or_die("\n");
140
141 FOR_EACH_SUPPORTED_FILTER(i) {
142 struct filter *f = (struct filter *)filter_get(i);
143
144 if (!f->help.short_help)
145 continue;
146 printf_or_die("\nOptions for %s (%s):", f->name,
147 f->help.purpose);
148 ggo_print_help(&f->help, flags);
149 }
150 }
151
152 /**
153 * Set select timeout of the scheduler.
154 *
155 * \param s The scheduler.
156 * \param context Pointer to the filter node (task context).
157 *
158 * This looks at the status of the btr node of the filter. If data is available
159 * in the input queue of the filter, or if an error occurred, a minimal timeout
160 * for the next select call is requested from the scheduler. Otherwise the
161 * scheduler timeout is left unchanged.
162 */
163 void generic_filter_pre_select(struct sched *s, void *context)
164 {
165 struct filter_node *fn = context;
166
167 if (btr_node_status(fn->btrn, fn->min_iqs, BTR_NT_INTERNAL) != 0)
168 sched_min_delay(s);
169 }
170
171 #ifdef WORDS_BIGENDIAN
172 #define DECODER_SAMPLE_FORMAT SF_S16_BE
173 #else
174 #define DECODER_SAMPLE_FORMAT SF_S16_LE
175 #endif
176
177 /**
178 * Execute a btr command for a decoder.
179 *
180 * The buffer tree nodes of the writers ask the parent nodes about sample_rate,
181 * channels count and sample format. This function is called by all decoders to
182 * answer these queries.
183 *
184 * \param cmd The command to be executed by the child node.
185 * \param sample_rate Known to the decoder.
186 * \param channels Known to the decoder.
187 * \param result Ascii representation on the answer is stored here.
188 *
189 * \return Standard.
190 */
191 int decoder_execute(const char *cmd, unsigned sample_rate, unsigned channels,
192 char **result)
193 {
194 if (!strcmp(cmd, "sample_rate")) {
195 if (sample_rate == 0)
196 return -E_BTR_NAVAIL;
197 *result = make_message("%u", sample_rate);
198 return 1;
199 }
200 if (!strcmp(cmd, "channels")) {
201 if (channels == 0)
202 return -E_BTR_NAVAIL;
203 *result = make_message("%u", channels);
204 return 1;
205 }
206 if (!strcmp(cmd, "sample_format")) {
207 *result = make_message("%d", DECODER_SAMPLE_FORMAT);
208 return 1;
209 }
210 return -ERRNO_TO_PARA_ERROR(ENOTSUP);
211 }