wav_filter.c

   1 /*
   2  * Copyright (C) 2005-2011 Andre Noll <maan@systemlinux.org>
   3  *
   4  * Licensed under the GPL v2. For licencing details see COPYING.
   5  */
   6
   7 /** \file wav_filter.c A filter that inserts a wave header. */
   8
   9 #include <regex.h>
  10 #include <stdbool.h>
  11
  12 #include "para.h"
  13 #include "error.h"
  14 #include "list.h"
  15 #include "sched.h"
  16 #include "ggo.h"
  17 #include "buffer_tree.h"
  18 #include "filter.h"
  19 #include "string.h"
  20 #include "portable_io.h"
  21
  22 /** A wav header is always 44 bytes. */
  23 #define WAV_HEADER_LEN 44
  24 /** Always write 16 bit header. */
  25 #define BITS 16
  26
  27 static void make_wav_header(unsigned int channels, unsigned int sample_rate,
  28                 char *headbuf)
  29 {
  30
  31         unsigned int size = 0x7fffffff;
  32         int bytespersec = channels * sample_rate * BITS / 8;
  33         int align = channels * BITS / 8;
  34
  35         PARA_DEBUG_LOG("writing wave header: %d channels, %d KHz\n", channels, sample_rate);
  36         memset(headbuf, 0, WAV_HEADER_LEN);
  37         memcpy(headbuf, "RIFF", 4);
  38         write_u32(headbuf + 4, size - 8);
  39         memcpy(headbuf + 8, "WAVE", 4);
  40         memcpy(headbuf + 12, "fmt ", 4);
  41         write_u32(headbuf + 16, 16); /* 16 + extra format bytes (zero) */
  42         write_u16(headbuf + 20, 1);     /* format (1 == PCM/uncompressed) */
  43         write_u16(headbuf + 22, channels);
  44         write_u32(headbuf + 24, sample_rate);
  45         write_u32(headbuf + 28, bytespersec);
  46         write_u16(headbuf + 32, align); /* number of bytes per sample slice */
  47         write_u16(headbuf + 34, BITS); /* significant bits per sample */
  48         memcpy(headbuf + 36, "data", 4); /* chunk ID */
  49         write_u32(headbuf + 40, size - 44); /* chunk size */
  50 }
  51
  52 static void wav_close(struct filter_node *fn)
  53 {
  54         free(fn->private_data);
  55         fn->private_data = NULL;
  56 }
  57
  58 static void wav_open(struct filter_node *fn)
  59 {
  60         int *bof;
  61
  62         fn->private_data = para_malloc(sizeof(int));
  63         bof = fn->private_data;
  64         *bof = 1;
  65 }
  66
  67 static void wav_pre_select(struct sched *s, struct task *t)
  68 {
  69         struct filter_node *fn = container_of(t, struct filter_node, task);
  70         size_t iqs = btr_get_input_queue_size(fn->btrn);
  71
  72         t->error = 0;
  73         if (iqs == 0)
  74                 return;
  75         sched_min_delay(s);
  76 }
  77
  78 static void wav_post_select(__a_unused struct sched *s, struct task *t)
  79 {
  80         struct filter_node *fn = container_of(t, struct filter_node, task);
  81         struct btr_node *btrn = fn->btrn;
  82         size_t iqs = btr_get_input_queue_size(btrn);
  83         int ret;
  84         char *header, *buf;
  85         int32_t rate, ch;
  86
  87         t->error = 0;
  88         if (iqs == 0) {
  89                 ret = -E_WAV_EOF;
  90                 if (btr_no_parent(btrn))
  91                         goto err;
  92                 return;
  93         }
  94         ret = btr_exec_up(btrn, "sample_rate", &buf);
  95         if (ret < 0) {
  96                 ret = -E_WAV_BAD_FC;
  97                 goto err;
  98         }
  99         ret = para_atoi32(buf, &rate);
 100         free(buf);
 101         if (ret < 0)
 102                 goto err;
 103         ret = btr_exec_up(btrn, "channels", &buf);
 104         if (ret < 0) {
 105                 ret = -E_WAV_BAD_FC;
 106                 goto err;
 107         }
 108         ret = para_atoi32(buf, &ch);
 109         free(buf);
 110         if (ret < 0)
 111                 goto err;
 112         header = para_malloc(WAV_HEADER_LEN);
 113         make_wav_header(ch, rate, header);
 114         btr_add_output(header, WAV_HEADER_LEN, btrn);
 115         ret = -E_WAV_SUCCESS;
 116 err:
 117         t->error = ret;
 118         if (ret == -E_WAV_SUCCESS)
 119                 btr_splice_out_node(btrn);
 120         else {
 121                 btr_remove_node(btrn);
 122                 PARA_ERROR_LOG("%s\n", para_strerror(-ret));
 123         }
 124 }
 125
 126 /**
 127  * The init function of the wav filter.
 128  *
 129  * \param f Structure to initialize.
 130  */
 131 void wav_filter_init(struct filter *f)
 132 {
 133         f->close = wav_close;
 134         f->open = wav_open;
 135         f->pre_select = wav_pre_select;
 136         f->post_select = wav_post_select;
 137 }