check_wav.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 check_wav.c Detect and delete a wav header. */
   8
   9 #include <regex.h>
  10
  11 #include "para.h"
  12 #include "string.h"
  13 #include "list.h"
  14 #include "sched.h"
  15 #include "buffer_tree.h"
  16 #include "error.h"
  17 #include "check_wav.h"
  18
  19 /** Length of a standard wav header. */
  20 #define WAV_HEADER_LEN 44
  21
  22 enum check_wav_state {
  23         CWS_NEED_HEADER,
  24         CWS_HAVE_HEADER,
  25         CWS_NO_HEADER,
  26 };
  27
  28 struct check_wav_context {
  29         enum check_wav_state state;
  30         struct btr_node *btrn;
  31         size_t min_iqs;
  32         /* Command line args. */
  33         struct wav_params params;
  34         /* Extracted from the wav header.*/
  35         unsigned channels;
  36         unsigned sample_format;
  37         unsigned sample_rate;
  38 };
  39
  40 void check_wav_pre_select(struct sched *s, struct check_wav_context *cwc)
  41 {
  42         int ret = btr_node_status(cwc->btrn, cwc->min_iqs, BTR_NT_INTERNAL);
  43         if (ret != 0)
  44                 sched_min_delay(s);
  45 }
  46
  47 static int check_wav_exec(struct btr_node *btrn, const char *cmd, char **result)
  48 {
  49         struct check_wav_context *cwc = btr_context(btrn);
  50         int val, header_val, given, arg;
  51
  52         header_val = cwc->channels;
  53         arg = cwc->params.channels_arg;
  54         given = cwc->params.channels_given;
  55         if (!strcmp(cmd, "channels"))
  56                 goto out;
  57
  58         header_val = cwc->sample_rate;
  59         arg = cwc->params.sample_rate_arg;
  60         given = cwc->params.sample_rate_given;
  61         if (!strcmp(cmd, "sample_rate"))
  62                 goto out;
  63
  64         header_val = cwc->sample_format;
  65         arg = cwc->params.sample_format_arg;
  66         given = cwc->params.sample_format_given;
  67         if (!strcmp(cmd, "sample_format"))
  68                 goto out;
  69
  70         return -ERRNO_TO_PARA_ERROR(ENOTSUP);
  71 out:
  72         if (given)
  73                 val = arg;
  74         else {
  75                 switch (cwc->state) {
  76                 case CWS_HAVE_HEADER:
  77                         val = header_val;
  78                         break;
  79                 case CWS_NO_HEADER:
  80                         /* Use default value */
  81                         val = arg;
  82                         break;
  83                 default:
  84                         return -E_BTR_NAVAIL;
  85                 }
  86         }
  87         *result = make_message("%d", val);
  88         return 1;
  89 }
  90
  91 int check_wav_post_select(struct check_wav_context *cwc)
  92 {
  93         struct btr_node *btrn = cwc->btrn;
  94         unsigned char *a;
  95         size_t sz;
  96         int ret;
  97         uint16_t bps; /* bits per sample */
  98         const char *sample_formats[] = {SAMPLE_FORMATS};
  99
 100         ret = btr_node_status(btrn, cwc->min_iqs, BTR_NT_INTERNAL);
 101         if (ret <= 0)
 102                 goto out;
 103         if (cwc->state != CWS_NEED_HEADER)
 104                 goto pushdown;
 105         btr_merge(btrn, cwc->min_iqs);
 106         sz = btr_next_buffer(btrn, (char **)&a);
 107         if (sz < cwc->min_iqs) /* file size less than WAV_HEADER_SIZE */
 108                 goto pushdown;
 109         cwc->min_iqs = 0;
 110         /*
 111          * The default byte ordering assumed for WAVE data files is
 112          * little-endian. Files written using the big-endian byte ordering
 113          * scheme have the identifier RIFX instead of RIFF.
 114          */
 115         if (a[0] != 'R' || a[1] != 'I' || a[2] != 'F' ||
 116                         (a[3] != 'F' && a[3] != 'X')) {
 117                 PARA_NOTICE_LOG("wav header not found\n");
 118                 cwc->state = CWS_NO_HEADER;
 119                 goto out;
 120         }
 121         PARA_INFO_LOG("found wav header\n");
 122         cwc->state = CWS_HAVE_HEADER;
 123         /* Only set those values which have not already been set. */
 124         cwc->channels = (unsigned)a[22];
 125         cwc->sample_rate = a[24] + (a[25] << 8) + (a[26] << 16) + (a[27] << 24);
 126         bps = a[34] + ((unsigned)a[35] << 8);
 127         if (bps != 8 && bps != 16) {
 128                 PARA_WARNING_LOG("%u bps not supported, assuming 16\n",
 129                         bps);
 130                 bps = 16;
 131         }
 132         /*
 133          * 8-bit samples are stored as unsigned bytes, ranging from 0
 134          * to 255.  16-bit samples are stored as 2's-complement signed
 135          * integers, ranging from -32768 to 32767.
 136          */
 137         if (bps == 8)
 138                 cwc->sample_format = SF_U8;
 139         else
 140                 cwc->sample_format = (a[3] == 'F')?
 141                         SF_S16_LE : SF_S16_BE;
 142         PARA_NOTICE_LOG("%dHz, %s, %s\n", cwc->sample_rate,
 143                 cwc->channels == 1? "mono" : "stereo",
 144                 sample_formats[cwc->sample_format]);
 145         btr_consume(btrn, WAV_HEADER_LEN);
 146 pushdown:
 147         btr_pushdown(btrn);
 148 out:
 149         if (ret < 0)
 150                 btr_remove_node(&cwc->btrn);
 151         return ret;
 152 }
 153
 154 struct check_wav_context *check_wav_init(struct btr_node *parent,
 155                 struct wav_params *params, struct btr_node **cw_btrn)
 156 {
 157         struct check_wav_context *cwc = para_calloc(sizeof(*cwc));
 158
 159         cwc->state = CWS_NEED_HEADER;
 160         cwc->min_iqs = WAV_HEADER_LEN;
 161         cwc->params = *params;
 162         cwc->btrn = btr_new_node(&(struct btr_node_description)
 163                 EMBRACE(.name = "check_wav", .parent = parent,
 164                 .handler = check_wav_exec, .context = cwc));
 165         if (cw_btrn)
 166                 *cw_btrn = cwc->btrn;
 167         return cwc;
 168 }
 169
 170 void check_wav_shutdown(struct check_wav_context *cwc)
 171 {
 172         free(cwc);
 173 }