Merge branch 't/compress'
[paraslash.git] / check_wav.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 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 /** The possible states of a check_wav instance. */
23 enum check_wav_state {
24 /** Initial state, less than \p WAV_HEADER_LEN bytes available. */
25 CWS_NEED_HEADER,
26 /** Wav hader was detected. */
27 CWS_HAVE_HEADER,
28 /** First part of the stream did not look like a wav header. */
29 CWS_NO_HEADER,
30 };
31
32 struct check_wav_context {
33 enum check_wav_state state;
34 struct btr_node *btrn;
35 size_t min_iqs;
36 /* Command line args. */
37 struct wav_params params;
38 /* Extracted from the wav header.*/
39 unsigned channels;
40 unsigned sample_format;
41 unsigned sample_rate;
42 };
43
44 /**
45 * Set select timeout according to the given context.
46 *
47 * \param s Contains the timeval that should be set.
48 * \param cwc Contains a pointer to the buffer tree node.
49 *
50 * This requests a minimal timeout from the scheduler if btrn of \a cwc is not
51 * idle.
52 */
53 void check_wav_pre_select(struct sched *s, struct check_wav_context *cwc)
54 {
55 int ret = btr_node_status(cwc->btrn, cwc->min_iqs, BTR_NT_INTERNAL);
56 if (ret != 0)
57 sched_min_delay(s);
58 }
59
60 static int check_wav_exec(struct btr_node *btrn, const char *cmd, char **result)
61 {
62 struct check_wav_context *cwc = btr_context(btrn);
63 int val, header_val, given, arg;
64
65 header_val = cwc->channels;
66 arg = cwc->params.channels_arg;
67 given = cwc->params.channels_given;
68 if (!strcmp(cmd, "channels"))
69 goto out;
70
71 header_val = cwc->sample_rate;
72 arg = cwc->params.sample_rate_arg;
73 given = cwc->params.sample_rate_given;
74 if (!strcmp(cmd, "sample_rate"))
75 goto out;
76
77 header_val = cwc->sample_format;
78 arg = cwc->params.sample_format_arg;
79 given = cwc->params.sample_format_given;
80 if (!strcmp(cmd, "sample_format"))
81 goto out;
82
83 return -ERRNO_TO_PARA_ERROR(ENOTSUP);
84 out:
85 if (given)
86 val = arg;
87 else {
88 switch (cwc->state) {
89 case CWS_HAVE_HEADER:
90 val = header_val;
91 break;
92 case CWS_NO_HEADER:
93 /*
94 * No wav header available and no value specified at
95 * the command line. Maybe one of our parent nodes
96 * knows.
97 */
98 if (btr_exec_up(btr_parent(cwc->btrn), cmd, result) >= 0)
99 return 1;
100 /* Use default value */
101 val = arg;
102 break;
103 default:
104 return -E_BTR_NAVAIL;
105 }
106 }
107 *result = make_message("%d", val);
108 return 1;
109 }
110
111 /**
112 * Filter out the wav header, pushdown everything else.
113 *
114 * \param cwc The context of this instance.
115 *
116 * This function looks at the first \p WAV_HEADER_SIZE bytes of the input queue
117 * of the btrn of \a cwc. If they look like a wav header, the function extracts
118 * the information of interest and swallows this part of the stream. Otherwise
119 * it is pushed down to all children. In either case the rest of the input is
120 * pushed down as well.
121 *
122 * Once the first part has been processed this way, the state of the instance
123 * changes from \p CWS_NEED_HEADER to \p CWS_HAVE_HEADER or \p CWS_NO_HEADER.
124 *
125 * \return Standard.
126 */
127 int check_wav_post_select(struct check_wav_context *cwc)
128 {
129 struct btr_node *btrn = cwc->btrn;
130 unsigned char *a;
131 size_t sz;
132 int ret;
133 uint16_t bps; /* bits per sample */
134 const char *sample_formats[] = {SAMPLE_FORMATS};
135
136 if (!btrn)
137 return 0;
138 ret = btr_node_status(btrn, cwc->min_iqs, BTR_NT_INTERNAL);
139 if (ret <= 0)
140 goto out;
141 if (cwc->state != CWS_NEED_HEADER)
142 goto pushdown;
143 btr_merge(btrn, cwc->min_iqs);
144 sz = btr_next_buffer(btrn, (char **)&a);
145 if (sz < cwc->min_iqs) /* file size less than WAV_HEADER_SIZE */
146 goto pushdown;
147 cwc->min_iqs = 0;
148 /*
149 * The default byte ordering assumed for WAVE data files is
150 * little-endian. Files written using the big-endian byte ordering
151 * scheme have the identifier RIFX instead of RIFF.
152 */
153 if (a[0] != 'R' || a[1] != 'I' || a[2] != 'F' ||
154 (a[3] != 'F' && a[3] != 'X')) {
155 PARA_NOTICE_LOG("wav header not found\n");
156 cwc->state = CWS_NO_HEADER;
157 goto out;
158 }
159 PARA_INFO_LOG("found wav header\n");
160 cwc->state = CWS_HAVE_HEADER;
161 /* Only set those values which have not already been set. */
162 cwc->channels = (unsigned)a[22];
163 cwc->sample_rate = a[24] + (a[25] << 8) + (a[26] << 16) + (a[27] << 24);
164 bps = a[34] + ((unsigned)a[35] << 8);
165 if (bps != 8 && bps != 16) {
166 PARA_WARNING_LOG("%u bps not supported, assuming 16\n",
167 bps);
168 bps = 16;
169 }
170 /*
171 * 8-bit samples are stored as unsigned bytes, ranging from 0
172 * to 255. 16-bit samples are stored as 2's-complement signed
173 * integers, ranging from -32768 to 32767.
174 */
175 if (bps == 8)
176 cwc->sample_format = SF_U8;
177 else
178 cwc->sample_format = (a[3] == 'F')?
179 SF_S16_LE : SF_S16_BE;
180 PARA_NOTICE_LOG("%dHz, %s, %s\n", cwc->sample_rate,
181 cwc->channels == 1? "mono" : "stereo",
182 sample_formats[cwc->sample_format]);
183 btr_consume(btrn, WAV_HEADER_LEN);
184 pushdown:
185 btr_pushdown(btrn);
186 out:
187 if (ret < 0)
188 btr_remove_node(&cwc->btrn);
189 return ret;
190 }
191
192 /**
193 * Allocate and set up a new check_wav instance.
194 *
195 * \param parent This buffer tree node will be the parent of the new node.
196 * \param child The child of the new node.
197 * \param params Default values and options.
198 * \param cw_btrn A pointer to the check wav node is returned here.
199 *
200 * This function also sets up the ->execute handler of the btrn so that all
201 * children of this node can figure out channel count, sample rate, etc.
202 *
203 * \return The (opaque) handle of the newly created check_wav instance. It is
204 * supposed to be passed to \ref check_wav_pre_select() and \ref
205 * check_wav_post_select().
206 *
207 * \sa \ref btr_new_node.
208 */
209 struct check_wav_context *check_wav_init(struct btr_node *parent,
210 struct btr_node *child, struct wav_params *params,
211 struct btr_node **cw_btrn)
212 {
213 struct check_wav_context *cwc = para_calloc(sizeof(*cwc));
214
215 cwc->state = CWS_NEED_HEADER;
216 cwc->min_iqs = WAV_HEADER_LEN;
217 cwc->params = *params;
218 cwc->btrn = btr_new_node(&(struct btr_node_description)
219 EMBRACE(.name = "check_wav", .parent = parent, .child = child,
220 .handler = check_wav_exec, .context = cwc));
221 if (cw_btrn)
222 *cw_btrn = cwc->btrn;
223 return cwc;
224 }
225
226 /**
227 * Dellocate all ressources of a check_wav instance.
228 *
229 * \param cwc Determines the instance to shut down.
230 *
231 * This function may only be called after check_wav_post_select() has returned
232 * negative.
233 */
234 void check_wav_shutdown(struct check_wav_context *cwc)
235 {
236 free(cwc);
237 }