filter_common.c

   1 /*
   2  * Copyright (C) 2005-2013 Andre Noll <maan@systemlinux.org>
   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 /** The array of supported filters. */
  23 struct filter filters[NUM_SUPPORTED_FILTERS] = {FILTER_ARRAY};
  24
  25 /**
  26  * Call the init function of each supported filter.
  27  * \sa filter::init
  28  */
  29 void filter_init(void)
  30 {
  31         int i;
  32
  33         FOR_EACH_SUPPORTED_FILTER(i)
  34                 filters[i].init(filters + i);
  35 }
  36
  37 /*
  38  * If the filter has a command line parser and options is not NULL, run it.
  39  * Returns filter_num on success, negative on errors
  40  */
  41 static int parse_filter_args(int filter_num, char *options, void **conf)
  42 {
  43         struct filter *f = &filters[filter_num];
  44         int ret, argc;
  45         char **argv;
  46
  47         if (!f->parse_config)
  48                 return strlen(options)? -E_BAD_FILTER_OPTIONS : filter_num;
  49         argc = create_shifted_argv(options, " \t", &argv);
  50         if (argc < 0)
  51                 return -E_BAD_FILTER_OPTIONS;
  52         argv[0] = para_strdup(f->name);
  53         ret = f->parse_config(argc, argv, conf);
  54         free_argv(argv);
  55         return ret < 0? ret : filter_num;
  56 }
  57
  58 /**
  59  * Check the filter command line options.
  60  *
  61  * \param fa The command line options.
  62  * \param conf Points to the filter configuration upon successful return.
  63  *
  64  * Check if \a fa starts with a the name of a supported filter, followed by
  65  * a colon. If yes, call the command line parser of that filter.
  66  *
  67  * \return On success, the number of the filter is returned and \a conf
  68  * is initialized to point to the filter configuration determined by \a fa.
  69  * On errors, a negative value is returned.
  70  *
  71  * Note: If \a fa specifies a filter that has no command line parser success is
  72  * returned, and \a conf is initialized to \p NULL.
  73  *
  74  * \sa filter::parse_config
  75  */
  76 int check_filter_arg(char *fa, void **conf)
  77 {
  78         int j;
  79
  80         *conf = NULL;
  81 //      PARA_DEBUG_LOG("arg: %s\n", fa);
  82         FOR_EACH_SUPPORTED_FILTER(j) {
  83                 const char *name = filters[j].name;
  84                 size_t len = strlen(name);
  85                 char c;
  86                 if (strlen(fa) < len)
  87                         continue;
  88                 if (strncmp(name, fa, len))
  89                         continue;
  90                 c = fa[len];
  91                 if (c && c != ' ')
  92                         continue;
  93                 if (c && !filters[j].parse_config)
  94                         return -E_BAD_FILTER_OPTIONS;
  95                 return parse_filter_args(j, c? fa + len + 1 :
  96                         fa + strlen(fa), conf);
  97         }
  98         return -E_UNSUPPORTED_FILTER;
  99 }
 100
 101 /**
 102  * Print help text of each filter to stdout.
 103  *
 104  * \param flags Passed to \ref ggo_print_help().
 105  */
 106 void print_filter_helps(unsigned flags)
 107 {
 108         int i, num = 0;
 109
 110         printf_or_die("\nAvailable filters: ");
 111         FOR_EACH_SUPPORTED_FILTER(i) {
 112                 if (num > 50) {
 113                         printf_or_die("\n                  ");
 114                         num = 0;
 115                 }
 116                 num += printf_or_die("%s%s", i? " " : "", filters[i].name);
 117         }
 118         printf_or_die("\n");
 119
 120         FOR_EACH_SUPPORTED_FILTER(i) {
 121                 struct filter *f = filters + i;
 122
 123                 if (!f->help.short_help)
 124                         continue;
 125                 printf_or_die("\nOptions for %s (%s):", f->name,
 126                         f->help.purpose);
 127                 ggo_print_help(&f->help, flags);
 128         }
 129 }
 130
 131 /**
 132  * Set select timeout of the scheduler.
 133  *
 134  * \param s The scheduler.
 135  * \param t The task struct of this filter.
 136  *
 137  * This looks at the status of the btr node of the filter. If data is available
 138  * in the input queue of the filter, or if an error occurred, a minimal timeout
 139  * for the next select call is requested from the scheduler. Otherwise the
 140  * scheduler timeout is left unchanged.
 141  */
 142 void generic_filter_pre_select(struct sched *s, struct task *t)
 143 {
 144         struct filter_node *fn = container_of(t, struct filter_node, task);
 145
 146         t->error = 0;
 147         if (btr_node_status(fn->btrn, fn->min_iqs, BTR_NT_INTERNAL) != 0)
 148                 sched_min_delay(s);
 149 }
 150
 151 #ifdef WORDS_BIGENDIAN
 152 #define DECODER_SAMPLE_FORMAT SF_S16_BE
 153 #else
 154 #define DECODER_SAMPLE_FORMAT SF_S16_LE
 155 #endif
 156
 157 /**
 158  * Execute a btr command for a decoder.
 159  *
 160  * The buffer tree nodes of the writers ask the parent nodes about sample_rate,
 161  * channels count and sample format. This function is called by all decoders to
 162  * answer these queries.
 163  *
 164  * \param cmd The command to be executed by the child node.
 165  * \param sample_rate Known to the decoder.
 166  * \param channels Known to the decoder.
 167  * \param result Ascii representation on the answer is stored here.
 168  *
 169  * \return Standard.
 170  */
 171 int decoder_execute(const char *cmd, unsigned sample_rate, unsigned channels,
 172                 char **result)
 173 {
 174         if (!strcmp(cmd, "sample_rate")) {
 175                 if (sample_rate == 0)
 176                         return -E_BTR_NAVAIL;
 177                 *result = make_message("%u", sample_rate);
 178                 return 1;
 179         }
 180         if (!strcmp(cmd, "channels")) {
 181                 if (channels == 0)
 182                         return -E_BTR_NAVAIL;
 183                 *result = make_message("%u", channels);
 184                 return 1;
 185         }
 186         if (!strcmp(cmd, "sample_format")) {
 187                 *result = make_message("%u", DECODER_SAMPLE_FORMAT);
 188                 return 1;
 189         }
 190         return -ERRNO_TO_PARA_ERROR(ENOTSUP);
 191 }