write.h

   1 /*
   2  * Copyright (C) 2006 Andre Noll <maan@systemlinux.org>
   3  *
   4  *     This program is free software; you can redistribute it and/or modify
   5  *     it under the terms of the GNU General Public License as published by
   6  *     the Free Software Foundation; either version 2 of the License, or
   7  *     (at your option) any later version.
   8  *
   9  *     This program is distributed in the hope that it will be useful,
  10  *     but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  *     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  *     GNU General Public License for more details.
  13  *
  14  *     You should have received a copy of the GNU General Public License
  15  *     along with this program; if not, write to the Free Software
  16  *     Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111, USA.
  17  */
  18
  19 /** \file write.h writer-related structures */
  20
  21 /** the list of supported writers */
  22 enum writer_enum {WRITER_ENUM};
  23
  24 /**
  25  * decbribes one running instance of a writer
  26  */
  27 struct writer_node {
  28         /** points to the writer structure associated with this node */
  29         struct writer *writer; /* FIXME: Should better be only the number */
  30         /** writer-specific data */
  31         void *private_data;
  32         /** send that many bytes in one go */
  33         int chunk_bytes;
  34         /** pointer to the group this node belongs to */
  35         struct writer_node_group *wng;
  36         /** the writer-specific configuration of this node */
  37         void *conf;
  38         /** how much of the wng's buffer is already written */
  39         size_t written;
  40 };
  41
  42 /** describes one supported writer */
  43 struct writer {
  44         /**
  45          * the init function of the writer
  46          *
  47          * It must fill in all other function pointers of the given
  48          * writer structure.
  49          *
  50          */
  51         void (*init)(struct writer *w);
  52         /**
  53          *
  54          *
  55          * the command line parser of the writer
  56          *
  57          * It should check whether the command line options given by \a options are
  58          * valid.  On success, it should return a pointer to the writer-specific
  59          * configuration data determined by \a options.  Note that this might be called
  60          * more than once with different values of \a options.
  61          *
  62          */
  63                 void * (*parse_config)(char *options);
  64         /**
  65          *
  66          * open one instance of this writer
  67          *
  68          * This function should perform any work necessary to write the incoming
  69          * stream. If To this aim, it may allocate its private data structure and store
  70          * a pointer to that structure via the given writer_node paramenter.
  71          */
  72         int (*open)(struct writer_node *);
  73         /**
  74          *
  75          * write a chunk of audio data
  76          *
  77          * This is called from the driving application whenever a data block of \a
  78          * chunk_bytes is available. It must return the number of bytes consumed from
  79          * \a data on success, and negative on errors.
  80          *
  81          */
  82         int (*write)(char *data, size_t nbytes, struct writer_node *);
  83         int (*pre_select)(struct sched *s, struct writer_node *wn);
  84         int (*post_select)(struct sched *s, struct writer_node *wn);
  85         /**
  86          * close one instance of the writer
  87          *
  88          * This function is assumed to succeed.
  89          */
  90         void (*close)(struct writer_node *);
  91         /**
  92          * shutdown the writer
  93          *
  94          * This is a optional function pointer used for cleaning
  95          * up.
  96          */
  97         void (*shutdown)(struct writer_node *);
  98 };
  99
 100 /**
 101  * describes a set of writer nodes that all write the same stream.
 102  */
 103 struct writer_node_group {
 104         /** number of nodes belonging to this group */
 105         unsigned num_writers;
 106         /** array of pointers to the corresponding writer nodes */
 107         struct writer_node *writer_nodes;
 108         /** the maximum of the chunk_bytes values of the writer nodes in this group */
 109         size_t max_chunk_bytes;
 110         /** non-zero if end of file was encountered */
 111         int *input_eof;
 112         int eof;
 113         char *buf;
 114         unsigned int *channels;
 115         unsigned int *samplerate;
 116         size_t *loaded;
 117         struct task task;
 118 };
 119
 120 /** loop over each writer node in a writer group */
 121 #define FOR_EACH_WRITER_NODE(i, wng) for (i = 0; i < (wng)->num_writers; i++)
 122 /** loop over each supported writer */
 123 #define FOR_EACH_WRITER(i) for (i = 0; i < NUM_SUPPORTED_WRITERS; i++)
 124
 125 /** declare the init functions of all supported writers */
 126 DECLARE_WRITER_INITS;
 127
 128 /** array containing the name of each writer */
 129 extern const char *writer_names[];
 130
 131 /** the writer structure for each supported writer */
 132 extern struct writer writers[NUM_SUPPORTED_WRITERS];