aboutsummaryrefslogtreecommitdiffstats
path: root/lv2/lv2plug.in/ns/ext/atom/forge.h
blob: 27907786bcd0a156cf876e97de786a1345829e4d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
/*
  Copyright 2008-2012 David Robillard <http://drobilla.net>

  Permission to use, copy, modify, and/or distribute this software for any
  purpose with or without fee is hereby granted, provided that the above
  copyright notice and this permission notice appear in all copies.

  THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/

/**
   @file forge.h An API for constructing LV2 atoms.

   This file provides a simple API which can be used to create complex nested
   atoms by calling the provided functions to append atoms (or atom headers) in
   the correct order.  The size of the parent atom is automatically updated,
   but the caller must handle this situation if atoms are more deeply nested.

   All output is written to a user-provided buffer.  This entire API is
   realtime safe and suitable for writing to output port buffers in the run
   method.

   Note these functions are all static inline, do not take their address.

   This header is non-normative, it is provided for convenience.
*/

#ifndef LV2_ATOM_FORGE_H
#define LV2_ATOM_FORGE_H

#include <assert.h>
#include <string.h>

#include "lv2/lv2plug.in/ns/ext/atom/atom-helpers.h"
#include "lv2/lv2plug.in/ns/ext/atom/atom.h"
#include "lv2/lv2plug.in/ns/ext/urid/urid.h"

#ifdef __cplusplus
extern "C" {
#else
#    include <stdbool.h>
#endif

/**
   A "forge" for creating atoms by appending to a buffer.
*/
typedef struct {
	uint8_t* buf;
	size_t   offset;
	size_t   size;

	LV2_URID Bool;
	LV2_URID Double;
	LV2_URID Float;
	LV2_URID Int32;
	LV2_URID Int64;
	LV2_URID Literal;
	LV2_URID Object;
	LV2_URID Property;
	LV2_URID Sequence;
	LV2_URID String;
	LV2_URID Tuple;
	LV2_URID URID;
	LV2_URID Vector;
} LV2_Atom_Forge;

/** Set the output buffer where @c forge will write atoms. */
static inline void
lv2_atom_forge_set_buffer(LV2_Atom_Forge* forge, uint8_t* buf, size_t size)
{
	forge->buf    = buf;
	forge->size   = size;
	forge->offset = 0;
}

/**
   Initialise @c forge.

   URIs will be mapped using @c map and stored, a reference to @c map itself is
   not held.
*/
static inline void
lv2_atom_forge_init(LV2_Atom_Forge* forge, LV2_URID_Map* map)
{
	lv2_atom_forge_set_buffer(forge, NULL, 0);
	forge->Bool     = map->map(map->handle, LV2_ATOM_URI "#Bool");
	forge->Double   = map->map(map->handle, LV2_ATOM_URI "#Double");
	forge->Float    = map->map(map->handle, LV2_ATOM_URI "#Float");
	forge->Int32    = map->map(map->handle, LV2_ATOM_URI "#Int32");
	forge->Int64    = map->map(map->handle, LV2_ATOM_URI "#Int64");
	forge->Literal  = map->map(map->handle, LV2_ATOM_URI "#Literal");
	forge->Object   = map->map(map->handle, LV2_ATOM_URI "#Object");
	forge->Property = map->map(map->handle, LV2_ATOM_URI "#Property");
	forge->Sequence = map->map(map->handle, LV2_ATOM_URI "#Sequence");
	forge->String   = map->map(map->handle, LV2_ATOM_URI "#String");
	forge->Tuple    = map->map(map->handle, LV2_ATOM_URI "#Tuple");
	forge->URID     = map->map(map->handle, LV2_ATOM_URI "#URID");
	forge->Vector   = map->map(map->handle, LV2_ATOM_URI "#Vector");
}

/**
   Reserve @c size bytes in the output buffer (used internally).
   @return The start of the reserved memory, or NULL if out of space.
*/
static inline uint8_t*
lv2_atom_forge_reserve(LV2_Atom_Forge* forge,
                       LV2_Atom*       parent,
                       uint32_t        size)
{
	uint8_t* const out         = forge->buf + forge->offset;
	const uint32_t padded_size = lv2_atom_pad_size(size);
	if (forge->offset + padded_size > forge->size) {
		return NULL;
	}
	if (parent) {
		parent->size += padded_size;
	}
	forge->offset += padded_size;
	return out;
}

/**
   Write the header of an atom:Atom.

   Space for the complete atom will be reserved, but uninitialised.
*/
static inline LV2_Atom*
lv2_atom_forge_atom_head(LV2_Atom_Forge* forge,
                         LV2_Atom*       parent,
                         uint32_t        type,
                         uint32_t        size)
{
	LV2_Atom* const out = (LV2_Atom*)lv2_atom_forge_reserve(
		forge, parent, size);
	if (out) {
		out->type = type;
		out->size = size - sizeof(LV2_Atom);
	}
	return out;
}

/** Write an atom:Int32. */
static inline LV2_Atom_Int32*
lv2_atom_forge_int32(LV2_Atom_Forge* forge, LV2_Atom* parent, int32_t val)
{
	LV2_Atom_Int32* out = (LV2_Atom_Int32*)lv2_atom_forge_atom_head(
		forge, parent, forge->Int32, sizeof(LV2_Atom_Int32));
	if (out) {
		out->value = val;
	}
	return out;
}

/** Write an atom:Int64. */
static inline LV2_Atom_Int64*
lv2_atom_forge_int64(LV2_Atom_Forge* forge, LV2_Atom* parent, int64_t val)
{
	LV2_Atom_Int64* out = (LV2_Atom_Int64*)lv2_atom_forge_atom_head(
		forge, parent, forge->Int64, sizeof(LV2_Atom_Int64));
	if (out) {
		out->value = val;
	}
	return out;
}

/** Write an atom:Float. */
static inline LV2_Atom_Float*
lv2_atom_forge_float(LV2_Atom_Forge* forge, LV2_Atom* parent, float val)
{
	LV2_Atom_Float* out = (LV2_Atom_Float*)lv2_atom_forge_atom_head(
		forge, parent, forge->Float, sizeof(LV2_Atom_Float));
	if (out) {
		out->value = val;
	}
	return out;
}

/** Write an atom:Double. */
static inline LV2_Atom_Double*
lv2_atom_forge_double(LV2_Atom_Forge* forge, LV2_Atom* parent, double val)
{
	LV2_Atom_Double* out = (LV2_Atom_Double*)lv2_atom_forge_atom_head(
		forge, parent, forge->Double, sizeof(LV2_Atom_Double));
	if (out) {
		out->value = val;
	}
	return out;
}

/** Write an atom:Bool. */
static inline LV2_Atom_Bool*
lv2_atom_forge_bool(LV2_Atom_Forge* forge, LV2_Atom* parent, bool val)
{
	LV2_Atom_Bool* out = (LV2_Atom_Bool*)lv2_atom_forge_atom_head(
		forge, parent, forge->Bool, sizeof(LV2_Atom_Bool));
	if (out) {
		out->value = val ? 1 : 0;
	}
	return out;
}

/** Write an atom:URID. */
static inline LV2_Atom_URID*
lv2_atom_forge_urid(LV2_Atom_Forge* forge, LV2_Atom* parent, LV2_URID id)
{
	LV2_Atom_URID* out = (LV2_Atom_URID*)lv2_atom_forge_reserve(
		forge, parent, sizeof(LV2_Atom_URID));
	if (out) {
		out->atom.type = forge->URID;
		out->atom.size = sizeof(uint32_t);
		out->id        = id;
	}
	return out;
}

/** Write an atom:String. */
static inline LV2_Atom_String*
lv2_atom_forge_string(LV2_Atom_Forge* forge,
                      LV2_Atom*       parent,
                      const uint8_t*  str,
                      size_t          len)
{
	LV2_Atom_String* out = (LV2_Atom_String*)lv2_atom_forge_reserve(
		forge, parent, sizeof(LV2_Atom_String) + len + 1);
	if (out) {
		out->atom.type = forge->String;
		out->atom.size = len + 1;
		assert(LV2_ATOM_CONTENTS(LV2_Atom_String, out) == LV2_ATOM_BODY(out));
		uint8_t* buf = LV2_ATOM_CONTENTS(LV2_Atom_String, out);
		memcpy(buf, str, len);
		buf[len] = '\0';
	}
	return out;
}

/** Write an atom:Literal. */
static inline LV2_Atom_Literal*
lv2_atom_forge_literal(LV2_Atom_Forge* forge,
                       LV2_Atom*       parent,
                       const uint8_t*  str,
                       size_t          len,
                       uint32_t        datatype,
                       uint32_t        lang)
{
	LV2_Atom_Literal* out = (LV2_Atom_Literal*)lv2_atom_forge_reserve(
		forge, parent, sizeof(LV2_Atom_Literal) + len + 1);
	if (out) {
		out->atom.type        = forge->Literal;
		out->atom.size        = sizeof(LV2_Atom_Literal_Head) + len + 1;
		out->literal.datatype = datatype;
		out->literal.lang     = lang;
		uint8_t* buf = LV2_ATOM_CONTENTS(LV2_Atom_Literal, out);
		memcpy(buf, str, len);
		buf[len] = '\0';
	}
	return out;
}

/** Write an atom:Vector header and reserve space for the body. */
static inline LV2_Atom_Vector*
lv2_atom_forge_reserve_vector(LV2_Atom_Forge* forge,
                              LV2_Atom*       parent,
                              uint32_t        elem_count,
                              uint32_t        elem_type,
                              uint32_t        elem_size)
{
	const size_t     size = sizeof(LV2_Atom_Vector) + (elem_size * elem_count);
	LV2_Atom_Vector* out  = (LV2_Atom_Vector*)lv2_atom_forge_reserve(
		forge, parent, size);
	if (out) {
		out->atom.type  = forge->Vector;
		out->atom.size  = size - sizeof(LV2_Atom);
		out->elem_count = elem_count;
		out->elem_type  = elem_type;
	}
	return out;
}

/** Write an atom:Vector. */
static inline LV2_Atom_Vector*
lv2_atom_forge_vector(LV2_Atom_Forge* forge,
                      LV2_Atom*       parent,
                      uint32_t        elem_count,
                      uint32_t        elem_type,
                      uint32_t        elem_size,
                      void*           elems)
{
	LV2_Atom_Vector* out = lv2_atom_forge_reserve_vector(
		forge, parent, elem_count, elem_type, elem_size);
	if (out) {
		uint8_t* buf = LV2_ATOM_CONTENTS(LV2_Atom_Vector, out);
		memcpy(buf, elems, elem_size * elem_count);
	}
	return out;
}

/**
   Write the header of an atom:Tuple.

   To complete the tuple, write a sequence of atoms, always passing the
   returned tuple as the @c parent parameter (or otherwise ensuring the size is
   updated correctly).

   For example:
   @code
   // Write tuple (1, 2.0)
   LV2_Atom* tup = (LV2_Atom*)lv2_atom_forge_tuple(forge, NULL);
   lv2_atom_forge_int32(forge, tup, 1);
   lv2_atom_forge_float(forge, tup, 2.0);
   @endcode
*/
static inline LV2_Atom_Tuple*
lv2_atom_forge_tuple(LV2_Atom_Forge* forge,
                     LV2_Atom*       parent)
{
	return (LV2_Atom_Tuple*)lv2_atom_forge_atom_head(
		forge, parent, forge->Tuple, sizeof(LV2_Atom));
}

/**
   Write the header of an atom:Object.

   To complete the object, write a sequence of properties, always passing the
   object as the @c parent parameter (or otherwise ensuring the size is updated
   correctly).

   For example:
   @code
   LV2_URID eg_Cat  = map("http://example.org/Cat");
   LV2_URID eg_name = map("http://example.org/name");

   // Write object header
   LV2_Atom* obj = (LV2_Atom*)lv2_atom_forge_object(forge, NULL, 0, eg_Cat);

   // Write property: eg:name = "Hobbes"
   lv2_atom_forge_property_head(forge, obj, eg_name, 0);
   lv2_atom_forge_string(forge, obj, "Hobbes", strlen("Hobbes"));
   @endcode
*/
static inline LV2_Atom_Object*
lv2_atom_forge_object(LV2_Atom_Forge* forge,
                      LV2_Atom*       parent,
                      LV2_URID        id,
                      LV2_URID        type)
{
	LV2_Atom_Object* out = (LV2_Atom_Object*)lv2_atom_forge_reserve(
		forge, parent, sizeof(LV2_Atom_Object));
	if (out) {
		out->atom.type = forge->Object;
		out->atom.size = sizeof(LV2_Atom_Object) - sizeof(LV2_Atom);
		out->id        = id;
		out->type      = type;
	}
	return out;
}

/**
   Write the header for a property body (likely in an Object).
   See lv2_atom_forge_object() documentation for an example.
*/
static inline LV2_Atom_Property_Body*
lv2_atom_forge_property_head(LV2_Atom_Forge* forge,
                             LV2_Atom*       parent,
                             LV2_URID        key,
                             LV2_URID        context)
{
	LV2_Atom_Property_Body* out = (LV2_Atom_Property_Body*)
		lv2_atom_forge_reserve(forge, parent, 2 * sizeof(uint32_t));
	if (out) {
		out->key     = key;
		out->context = context;
	}
	return out;
}

/**
   Write the header for a Sequence.
   The size of the returned sequence will be 0, so passing it as the parent
   parameter to other forge methods will do the right thing.
*/
static inline LV2_Atom_Sequence*
lv2_atom_forge_sequence_head(LV2_Atom_Forge* forge,
                             LV2_Atom*       parent,
                             uint32_t        capacity)
{
	LV2_Atom_Sequence* out = (LV2_Atom_Sequence*)
		lv2_atom_forge_reserve(forge, parent, sizeof(LV2_Atom_Sequence));
	if (out) {
		out->atom.type = forge->Sequence;
		out->atom.size = sizeof(LV2_Atom_Sequence) - sizeof(LV2_Atom);
		out->capacity  = capacity;
		out->pad       = 0;
	}
	return out;
}

/**
   Write the time stamp header of an Event (in a Sequence) in audio frames.
   After this, call the appropriate forge method(s) to write the body, passing
   the same @c parent parameter.  Note the returned LV2_Event is NOT an Atom.
*/
static inline LV2_Atom_Event*
lv2_atom_forge_audio_time(LV2_Atom_Forge* forge,
                          LV2_Atom*       parent,
                          uint32_t        frames,
                          uint32_t        subframes)
{
	LV2_Atom_Event* out = (LV2_Atom_Event*)
		lv2_atom_forge_reserve(forge, parent, 2 * sizeof(uint32_t));
	if (out) {
		out->time.audio.frames    = frames;
		out->time.audio.subframes = subframes;
	}
	return out;
}

/**
   Write the time stamp header of an Event (in a Sequence) in beats.
   After this, call the appropriate forge method(s) to write the body, passing
   the same @c parent parameter.  Note the returned LV2_Event is NOT an Atom.
*/
static inline LV2_Atom_Event*
lv2_atom_forge_beat_time(LV2_Atom_Forge* forge,
                         LV2_Atom*       parent,
                         double          beats)
{
	LV2_Atom_Event* out = (LV2_Atom_Event*)
		lv2_atom_forge_reserve(forge, parent, sizeof(double));
	if (out) {
		out->time.beats = beats;
	}
	return out;
}

#ifdef __cplusplus
}  /* extern "C" */
#endif

#endif  /* LV2_ATOM_FORGE_H */