wav_filter.c

   1 /*
   2  * Copyright (C) 2005-2012 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
  11 #include "para.h"
  12 #include "error.h"
  13 #include "list.h"
  14 #include "sched.h"
  15 #include "ggo.h"
  16 #include "buffer_tree.h"
  17 #include "filter.h"
  18 #include "string.h"
  19 #include "portable_io.h"
  20
  21 /** A wav header is always 44 bytes. */
  22 #define WAV_HEADER_LEN 44
  23 /** Always write 16 bit header. */
  24 #define BITS 16
  25
  26 static void make_wav_header(unsigned int channels, unsigned int sample_rate,
  27                 char *headbuf)
  28 {
  29
  30         unsigned int size = 0x7fffffff;
  31         int bytespersec = channels * sample_rate * BITS / 8;
  32         int align = channels * BITS / 8;
  33
  34         PARA_DEBUG_LOG("writing wave header: %d channels, %d KHz\n", channels, sample_rate);
  35         memset(headbuf, 0, WAV_HEADER_LEN);
  36         memcpy(headbuf, "RIFF", 4);
  37         write_u32(headbuf + 4, size - 8);
  38         memcpy(headbuf + 8, "WAVE", 4);
  39         memcpy(headbuf + 12, "fmt ", 4);
  40         write_u32(headbuf + 16, 16); /* 16 + extra format bytes (zero) */
  41         write_u16(headbuf + 20, 1);     /* format (1 == PCM/uncompressed) */
  42         write_u16(headbuf + 22, channels);
  43         write_u32(headbuf + 24, sample_rate);
  44         write_u32(headbuf + 28, bytespersec);
  45         write_u16(headbuf + 32, align); /* number of bytes per sample slice */
  46         write_u16(headbuf + 34, BITS); /* significant bits per sample */
  47         memcpy(headbuf + 36, "data", 4); /* chunk ID */
  48         write_u32(headbuf + 40, size - 44); /* chunk size */
  49 }
  50
  51 static void wav_close(struct filter_node *fn)
  52 {
  53         free(fn->private_data);
  54         fn->private_data = NULL;
  55 }
  56
  57 static void wav_open(struct filter_node *fn)
  58 {
  59         int *bof;
  60
  61         fn->private_data = para_malloc(sizeof(int));
  62         bof = fn->private_data;
  63         *bof = 1;
  64 }
  65
  66 static void wav_pre_select(struct sched *s, struct task *t)
  67 {
  68         struct filter_node *fn = container_of(t, struct filter_node, task);
  69         size_t iqs = btr_get_input_queue_size(fn->btrn);
  70
  71         t->error = 0;
  72         if (iqs == 0)
  73                 return;
  74         sched_min_delay(s);
  75 }
  76
  77 static void wav_post_select(__a_unused struct sched *s, struct task *t)
  78 {
  79         struct filter_node *fn = container_of(t, struct filter_node, task);
  80         struct btr_node *btrn = fn->btrn;
  81         size_t iqs = btr_get_input_queue_size(btrn);
  82         int ret;
  83         char *header, *buf;
  84         int32_t rate, ch;
  85
  86         t->error = 0;
  87         if (iqs == 0) {
  88                 ret = -E_WAV_EOF;
  89                 if (btr_no_parent(btrn))
  90                         goto err;
  91                 return;
  92         }
  93         ret = btr_exec_up(btrn, "sample_rate", &buf);
  94         if (ret < 0) {
  95                 ret = -E_WAV_BAD_FC;
  96                 goto err;
  97         }
  98         ret = para_atoi32(buf, &rate);
  99         free(buf);
 100         if (ret < 0)
 101                 goto err;
 102         ret = btr_exec_up(btrn, "channels", &buf);
 103         if (ret < 0) {
 104                 ret = -E_WAV_BAD_FC;
 105                 goto err;
 106         }
 107         ret = para_atoi32(buf, &ch);
 108         free(buf);
 109         if (ret < 0)
 110                 goto err;
 111         header = para_malloc(WAV_HEADER_LEN);
 112         make_wav_header(ch, rate, header);
 113         btr_add_output(header, WAV_HEADER_LEN, btrn);
 114         ret = -E_WAV_SUCCESS;
 115 err:
 116         t->error = ret;
 117         if (ret == -E_WAV_SUCCESS)
 118                 btr_splice_out_node(btrn);
 119         else {
 120                 btr_remove_node(btrn);
 121                 PARA_ERROR_LOG("%s\n", para_strerror(-ret));
 122         }
 123 }
 124
 125 /**
 126  * The init function of the wav filter.
 127  *
 128  * \param f Structure to initialize.
 129  */
 130 void wav_filter_init(struct filter *f)
 131 {
 132         f->close = wav_close;
 133         f->open = wav_open;
 134         f->pre_select = wav_pre_select;
 135         f->post_select = wav_post_select;
 136 }