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1 | /* -*-c-*- |
2 | * |
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3 | * $Id: au.h,v 1.2 2002/02/02 22:43:50 mdw Exp $ |
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4 | * |
5 | * Audio handling |
6 | * |
7 | * (c) 2002 Mark Wooding |
8 | */ |
9 | |
10 | /*----- Licensing notice --------------------------------------------------* |
11 | * |
12 | * This file is part of Jog: Programming for a jogging machine. |
13 | * |
14 | * Jog is free software; you can redistribute it and/or modify |
15 | * it under the terms of the GNU General Public License as published by |
16 | * the Free Software Foundation; either version 2 of the License, or |
17 | * (at your option) any later version. |
18 | * |
19 | * Jog is distributed in the hope that it will be useful, |
20 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
21 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
22 | * GNU General Public License for more details. |
23 | * |
24 | * You should have received a copy of the GNU General Public License |
25 | * along with Jog; if not, write to the Free Software Foundation, |
26 | * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
27 | */ |
28 | |
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29 | #ifndef AU_H |
30 | #define AU_H |
31 | |
32 | #ifdef __cplusplus |
33 | extern "C" { |
34 | #endif |
35 | |
36 | /*----- Header files ------------------------------------------------------*/ |
37 | |
38 | #include <stddef.h> |
39 | |
40 | #include <mLib/bits.h> |
41 | #include <mLib/sym.h> |
42 | |
43 | /*----- Data structures ---------------------------------------------------*/ |
44 | |
45 | /* --- An audio sample --- * |
46 | * |
47 | * We maintain a cache of sample data, keyed by textual tags. An entry in |
48 | * the cache may indicate one of three states: |
49 | * |
50 | * * a tag for a sample which doesn't exist (negative answer); |
51 | * |
52 | * * a sample whose data is currently resident; or |
53 | * |
54 | * * sample with nonresident data. |
55 | * |
56 | * A negative answer is indicated by the @AUF_NOMATCH@ flag. If an entry has |
57 | * resident data, the @a@ pointer is non-null. |
58 | */ |
59 | |
60 | typedef struct au_sample { |
61 | sym_base s; /* Base structure for name lookup */ |
62 | unsigned f; /* Flags for this entry */ |
63 | struct au_data *a; /* Sample data, if present */ |
64 | } au_sample; |
65 | |
66 | #define AUF_NOMATCH 1u /* Cached non-match for this tag */ |
67 | |
68 | /* --- Audio data --- * |
69 | * |
70 | * The actual sample data, in an internal representation chosen by the |
71 | * system-specific layer. |
72 | * |
73 | * The sample data can be in one of two states: in-use or spare. Sample data |
74 | * is considered to be in-use if the @ref@ field is nonzero. Spare sample |
75 | * data is left in-memory for efficiency's sake, but will be discarded |
76 | * (least-recently-used first) when the total size of sample data (as |
77 | * measured by the @sz@ fields) exceeds @AU_CACHEMAX@. |
78 | */ |
79 | |
80 | typedef struct au_data { |
81 | struct au_data *next, *prev; /* Other samples in this list */ |
82 | unsigned ref; /* Reference count for sample data */ |
83 | struct au_sample *s; /* Parent sample node */ |
84 | octet *p; /* Pointer to sample file data */ |
85 | size_t sz; /* Size of sample file data */ |
86 | } au_data; |
87 | |
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88 | /* --- Audio cache information --- */ |
89 | |
90 | typedef struct au_cacheinfo { |
91 | size_t sz_max; /* Maximum allowed cache size */ |
92 | size_t sz_total; /* Total size used by samples */ |
93 | size_t sz_spare; /* Size used by `spare' samples */ |
94 | size_t sz_queue; /* Size used by queued samples */ |
95 | unsigned n_total; /* Total number of cached samples */ |
96 | unsigned n_spare; /* Number of `spare' samples */ |
97 | unsigned n_queue; /* Number of queued samples */ |
98 | unsigned long hits; /* Number of cache hits */ |
99 | unsigned long misses; /* Number of cache misses */ |
100 | } au_cacheinfo; |
101 | |
102 | #define AU_CACHEMAX 0x01000000 /* Default cache maximum size */ |
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103 | |
104 | /*----- Functions provided ------------------------------------------------*/ |
105 | |
106 | /* --- @au_init@ --- * |
107 | * |
108 | * Arguments: @const char *dir@ = samples directory, or null |
109 | * @size_t max@ = maximum cache size |
110 | * |
111 | * Returns: --- |
112 | * |
113 | * Use: Initializes the audio subsystem. |
114 | */ |
115 | |
116 | extern void au_init(const char */*dir*/, size_t /*max*/); |
117 | |
118 | /* --- @au_shutdown@ --- * |
119 | * |
120 | * Arguments: --- |
121 | * |
122 | * Returns: --- |
123 | * |
124 | * Use: Shuts down the audio subsystem. |
125 | */ |
126 | |
127 | extern void au_shutdown(void); |
128 | |
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129 | /* --- @au_getcacheinfo@ --- * |
130 | * |
131 | * Arguments: @au_cacheinfo *c@ = where to put the information |
132 | * |
133 | * Returns: --- |
134 | * |
135 | * Use: Extracts audio cache information. |
136 | */ |
137 | |
138 | extern void au_getcacheinfo(au_cacheinfo */*c*/); |
139 | |
140 | /* --- @au_setcachelimit@ --- * |
141 | * |
142 | * Arguments: @size_t max@ = new cache limit |
143 | * |
144 | * Returns: --- |
145 | * |
146 | * Use: Reconfigures the maximum cache size. This probably isn't |
147 | * very useful, but it was easy... |
148 | */ |
149 | |
150 | extern void au_setcachelimit(size_t /*max*/); |
151 | |
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152 | /* --- @au_find@ --- * |
153 | * |
154 | * Arguments: @const char *tag@ = sample tag string |
155 | * |
156 | * Returns: A pointer to the sample corresponding to the tag, or null if |
157 | * the sample wasn't found. |
158 | * |
159 | * Use: Looks up a sample by its name. |
160 | */ |
161 | |
162 | extern au_sample *au_find(const char */*tag*/); |
163 | |
164 | /* --- @au_fetch@ --- * |
165 | * |
166 | * Arguments: @au_sample *s@ = sample pointer |
167 | * |
168 | * Returns: A pointer to the audio data for the sample. |
169 | * |
170 | * Use: Fetches a sample, and decodes it, if necessary. The decoded |
171 | * sample data is left with an outstanding reference to it, so |
172 | * it won't be freed. This is used internally by @au_queue@, |
173 | * before passing the fetched sample data to the system-specific |
174 | * layer for playback. It can also be used to lock sample data |
175 | * in memory (e.g., for the `abort' error message), or (by |
176 | * freeing it immediately afterwards) to prefetch a sample which |
177 | * will be used soon, to reduce the latency before the sample is |
178 | * heard. |
179 | */ |
180 | |
181 | extern au_data *au_fetch(au_sample */*s*/); |
182 | |
183 | /* --- @au_queue@ --- * |
184 | * |
185 | * Arguments: @au_sample *s@ = sample pointer |
186 | * |
187 | * Returns: Zero on success, nonzero on failure. |
188 | * |
189 | * Use: Queues a sample to be played. |
190 | */ |
191 | |
192 | extern int au_queue(au_sample */*s*/); |
193 | |
194 | /* --- @au_free@, @au_free_unlocked@ --- * |
195 | * |
196 | * Arguments: @au_data *a@ = pointer to audio data block |
197 | * |
198 | * Returns: --- |
199 | * |
200 | * Use: Frees a sample data block when it's no longer required. |
201 | */ |
202 | |
203 | extern void au_free(au_data */*a*/); |
204 | extern void au_free_unlocked(au_data */*a*/); |
205 | |
206 | /* --- @au_play@, @au_tryplay@ --- * |
207 | * |
208 | * Arguments: @const char *tag@ = sample tag string |
209 | * |
210 | * Returns: Zero on success, nonzero on failure. |
211 | * |
212 | * Use: Convenience functions for queueing samples by tag. |
213 | * If @au_tryplay@ cannot find the requested sample, it returns |
214 | * a zero value; if @au_play@ cannot find the sample, it aborts |
215 | * the program. |
216 | */ |
217 | |
218 | extern int au_play(const char */*tag*/); |
219 | extern int au_tryplay(const char */*tag*/); |
220 | |
221 | /*----- That's all, folks -------------------------------------------------*/ |
222 | |
223 | #ifdef __cplusplus |
224 | } |
225 | #endif |
226 | |
227 | #endif |