1 /*****************************************************************************
2 * block.c: Data blocks management functions
3 *****************************************************************************
4 * Copyright (C) 2003-2004 the VideoLAN team
5 * Copyright (C) 2007-2009 RĂ©mi Denis-Courmont
7 * Authors: Laurent Aimar <fenrir@videolan.org>
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License as published by
11 * the Free Software Foundation; either version 2 of the License, or
12 * (at your option) any later version.
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 * GNU General Public License for more details.
19 * You should have received a copy of the GNU General Public License
20 * along with this program; if not, write to the Free Software
21 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
22 *****************************************************************************/
24 /*****************************************************************************
26 *****************************************************************************/
31 #include <vlc_common.h>
34 #include "vlc_block.h"
37 * @section Block handling functions.
41 * Internal state for heap block.
46 size_t i_allocated_buffer;
47 uint8_t p_allocated_buffer[];
51 static void BlockNoRelease( block_t *b )
53 fprintf( stderr, "block %p has no release callback! This is a bug!\n", b );
58 void block_Init( block_t *restrict b, void *buf, size_t size )
60 /* Fill all fields to their default */
64 b->i_dts = VLC_TS_INVALID;
71 b->pf_release = BlockNoRelease;
75 static void BlockRelease( block_t *p_block )
80 static void BlockMetaCopy( block_t *restrict out, const block_t *in )
82 out->p_next = in->p_next;
83 out->i_dts = in->i_dts;
84 out->i_pts = in->i_pts;
85 out->i_flags = in->i_flags;
86 out->i_length = in->i_length;
87 out->i_rate = in->i_rate;
88 out->i_samples = in->i_samples;
91 /* Memory alignment */
92 #define BLOCK_ALIGN 16
93 /* Initial size of reserved header and footer */
94 #define BLOCK_PADDING_SIZE 32
95 /* Maximum size of reserved footer before we release with realloc() */
96 #define BLOCK_WASTE_SIZE 2048
98 block_t *block_Alloc( size_t i_size )
100 /* We do only one malloc
101 * TODO: bench if doing 2 malloc but keeping a pool of buffer is better
104 * 2 * BLOCK_PADDING_SIZE -> pre + post padding
106 const size_t i_alloc = i_size + 2 * BLOCK_PADDING_SIZE + BLOCK_ALIGN;
107 block_sys_t *p_sys = malloc( sizeof( *p_sys ) + i_alloc );
112 /* Fill opaque data */
113 p_sys->i_allocated_buffer = i_alloc;
115 block_Init( &p_sys->self, p_sys->p_allocated_buffer + BLOCK_PADDING_SIZE
117 - ((uintptr_t)p_sys->p_allocated_buffer % BLOCK_ALIGN),
119 p_sys->self.pf_release = BlockRelease;
124 block_t *block_Realloc( block_t *p_block, ssize_t i_prebody, size_t i_body )
126 block_sys_t *p_sys = (block_sys_t *)p_block;
127 size_t requested = i_prebody + i_body;
129 /* Corner case: empty block requested */
130 if( i_prebody <= 0 && i_body <= (size_t)(-i_prebody) )
132 block_Release( p_block );
136 if( p_block->pf_release != BlockRelease )
138 /* Special case when pf_release if overloaded
139 * TODO if used one day, then implement it in a smarter way */
140 block_t *p_dup = block_Duplicate( p_block );
141 block_Release( p_block );
146 p_sys = (block_sys_t *)p_block;
149 uint8_t *p_start = p_sys->p_allocated_buffer;
150 uint8_t *p_end = p_sys->p_allocated_buffer + p_sys->i_allocated_buffer;
152 assert( p_block->p_buffer + p_block->i_buffer <= p_end );
153 assert( p_block->p_buffer >= p_start );
155 /* Corner case: the current payload is discarded completely */
156 if( i_prebody <= 0 && p_block->i_buffer <= (size_t)-i_prebody )
157 p_block->i_buffer = 0; /* discard current payload */
158 if( p_block->i_buffer == 0 )
160 size_t available = p_end - p_start;
162 if( requested <= available )
163 { /* Enough room: recycle buffer */
164 size_t extra = available - requested;
166 p_block->p_buffer = p_start + (extra / 2);
167 p_block->i_buffer = requested;
170 /* Not enough room: allocate a new buffer */
171 block_t *p_rea = block_Alloc( requested );
173 BlockMetaCopy( p_rea, p_block );
174 block_Release( p_block );
178 /* First, shrink payload */
180 /* Pull payload start */
183 assert( p_block->i_buffer >= (size_t)-i_prebody );
184 p_block->p_buffer -= i_prebody;
185 p_block->i_buffer += i_prebody;
190 /* Trim payload end */
191 if( p_block->i_buffer > i_body )
192 p_block->i_buffer = i_body;
194 /* Second, reallocate the buffer if we lack space. This is done now to
195 * minimize the payload size for memory copy. */
196 assert( i_prebody >= 0 );
197 if( (size_t)(p_block->p_buffer - p_start) < (size_t)i_prebody
198 || (size_t)(p_end - p_block->p_buffer) < i_body )
200 /* FIXME: this is really dumb, we should use realloc() */
201 block_t *p_rea = block_Alloc( requested );
204 BlockMetaCopy( p_rea, p_block );
205 p_rea->p_buffer += i_prebody;
206 p_rea->i_buffer -= i_prebody;
207 memcpy( p_rea->p_buffer, p_block->p_buffer, p_block->i_buffer );
209 block_Release( p_block );
213 /* We have a very large reserved footer now? Release some of it.
214 * XXX it might not preserve the alignment of p_buffer */
215 if( p_end - (p_block->p_buffer + i_body) > BLOCK_WASTE_SIZE )
217 const ptrdiff_t i_prebody = p_block->p_buffer - p_start;
218 const size_t i_new = requested + 1 * BLOCK_PADDING_SIZE;
219 block_sys_t *p_new = realloc( p_sys, sizeof (*p_sys) + i_new );
224 p_sys->i_allocated_buffer = i_new;
225 p_block = &p_sys->self;
226 p_block->p_buffer = &p_sys->p_allocated_buffer[i_prebody];
230 /* NOTE: p_start and p_end are corrupted from this point */
232 /* Third, expand payload */
234 /* Push payload start */
237 p_block->p_buffer -= i_prebody;
238 p_block->i_buffer += i_prebody;
243 /* Expand payload to requested size */
244 p_block->i_buffer = i_body;
256 static void block_heap_Release (block_t *self)
258 block_heap_t *block = (block_heap_t *)self;
265 * Creates a block from a heap allocation.
266 * This is provided by LibVLC so that manually heap-allocated blocks can safely
267 * be deallocated even after the origin plugin has been unloaded from memory.
269 * When block_Release() is called, VLC will free() the specified pointer.
271 * @param ptr base address of the heap allocation (will be free()'d)
272 * @param addr base address of the useful buffer data
273 * @param length bytes length of the useful buffer datan
274 * @return NULL in case of error (ptr free()'d in that case), or a valid
277 block_t *block_heap_Alloc (void *ptr, void *addr, size_t length)
279 block_heap_t *block = malloc (sizeof (*block));
286 block_Init (&block->self, (uint8_t *)addr, length);
287 block->self.pf_release = block_heap_Release;
293 # include <sys/mman.h>
295 typedef struct block_mmap_t
302 static void block_mmap_Release (block_t *block)
304 block_mmap_t *p_sys = (block_mmap_t *)block;
306 munmap (p_sys->base_addr, p_sys->length);
311 * Creates a block from a virtual address memory mapping (mmap).
312 * This is provided by LibVLC so that mmap blocks can safely be deallocated
313 * even after the allocating plugin has been unloaded from memory.
315 * @param addr base address of the mapping (as returned by mmap)
316 * @param length length (bytes) of the mapping (as passed to mmap)
317 * @return NULL if addr is MAP_FAILED, or an error occurred (in the later
318 * case, munmap(addr, length) is invoked before returning).
320 block_t *block_mmap_Alloc (void *addr, size_t length)
322 if (addr == MAP_FAILED)
325 block_mmap_t *block = malloc (sizeof (*block));
328 munmap (addr, length);
332 block_Init (&block->self, (uint8_t *)addr, length);
333 block->self.pf_release = block_mmap_Release;
334 block->base_addr = addr;
335 block->length = length;
339 block_t *block_mmap_Alloc (void *addr, size_t length)
341 (void)addr; (void)length; return NULL;
348 #define _get_osfhandle(a) ((long) (a))
352 ssize_t pread (int fd, void *buf, size_t count, off_t offset)
354 HANDLE handle = (HANDLE)(intptr_t)_get_osfhandle (fd);
355 if (handle == INVALID_HANDLE_VALUE)
358 OVERLAPPED olap; olap.Offset = offset; olap.OffsetHigh = (offset >> 32);
360 /* This braindead API will override the file pointer even if we specify
361 * an explicit read offset... So do not expect this to mix well with
362 * regular read() calls. */
363 if (ReadFile (handle, buf, count, &written, &olap))
370 * Loads a file into a block of memory. If possible a private file mapping is
371 * created. Otherwise, the file is read normally. On 32-bits platforms, this
372 * function will not work for very large files, due to memory space
373 * constraints. Cancellation point.
375 * @param fd file descriptor to load from
376 * @return a new block with the file content at p_buffer, and file length at
377 * i_buffer (release it with block_Release()), or NULL upon error (see errno).
379 block_t *block_File (int fd)
384 /* First, get the file size */
388 /* st_size is meaningful for regular files, shared memory and typed memory.
389 * It's also meaning for symlinks, but that's not possible with fstat().
390 * In other cases, it's undefined, and we should really not go further. */
392 # define S_TYPEISSHM( buf ) (0)
394 if (S_ISDIR (st.st_mode))
399 if (!S_ISREG (st.st_mode) && !S_TYPEISSHM (&st))
405 /* Prevent an integer overflow in mmap() and malloc() */
406 if (st.st_size >= SIZE_MAX)
411 length = (size_t)st.st_size;
418 addr = mmap (NULL, length, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
419 if (addr != MAP_FAILED)
420 return block_mmap_Alloc (addr, length);
424 /* If mmap() is not implemented by the OS _or_ the filesystem... */
425 block_t *block = block_Alloc (length);
428 block_cleanup_push (block);
430 for (size_t i = 0; i < length;)
432 ssize_t len = pread (fd, block->p_buffer + i, length - i, i);
435 block_Release (block);
446 * @section Thread-safe block queue functions
450 * Internal state for block queues
454 vlc_mutex_t lock; /* fifo data lock */
455 vlc_cond_t wait; /**< Wait for data */
456 vlc_cond_t wait_room; /**< Wait for queue depth to shrink */
465 block_fifo_t *block_FifoNew( void )
467 block_fifo_t *p_fifo = malloc( sizeof( block_fifo_t ) );
471 vlc_mutex_init( &p_fifo->lock );
472 vlc_cond_init( &p_fifo->wait );
473 vlc_cond_init( &p_fifo->wait_room );
474 p_fifo->p_first = NULL;
475 p_fifo->pp_last = &p_fifo->p_first;
476 p_fifo->i_depth = p_fifo->i_size = 0;
477 p_fifo->b_force_wake = false;
482 void block_FifoRelease( block_fifo_t *p_fifo )
484 block_FifoEmpty( p_fifo );
485 vlc_cond_destroy( &p_fifo->wait_room );
486 vlc_cond_destroy( &p_fifo->wait );
487 vlc_mutex_destroy( &p_fifo->lock );
491 void block_FifoEmpty( block_fifo_t *p_fifo )
495 vlc_mutex_lock( &p_fifo->lock );
496 for( b = p_fifo->p_first; b != NULL; )
505 p_fifo->i_depth = p_fifo->i_size = 0;
506 p_fifo->p_first = NULL;
507 p_fifo->pp_last = &p_fifo->p_first;
508 vlc_cond_broadcast( &p_fifo->wait_room );
509 vlc_mutex_unlock( &p_fifo->lock );
513 * Wait until the FIFO gets below a certain size (if needed).
515 * Note that if more than one thread writes to the FIFO, you cannot assume that
516 * the FIFO is actually below the requested size upon return (since another
517 * thread could have refilled it already). This is typically not an issue, as
518 * this function is meant for (relaxed) congestion control.
520 * This function may be a cancellation point and it is cancel-safe.
522 * @param fifo queue to wait on
523 * @param max_depth wait until the queue has no more than this many blocks
524 * (use SIZE_MAX to ignore this constraint)
525 * @param max_size wait until the queue has no more than this many bytes
526 * (use SIZE_MAX to ignore this constraint)
529 void block_FifoPace (block_fifo_t *fifo, size_t max_depth, size_t max_size)
533 vlc_mutex_lock (&fifo->lock);
534 while ((fifo->i_depth > max_depth) || (fifo->i_size > max_size))
536 mutex_cleanup_push (&fifo->lock);
537 vlc_cond_wait (&fifo->wait_room, &fifo->lock);
540 vlc_mutex_unlock (&fifo->lock);
544 * Immediately queue one block at the end of a FIFO.
546 * @param block head of a block list to queue (may be NULL)
548 size_t block_FifoPut( block_fifo_t *p_fifo, block_t *p_block )
551 vlc_mutex_lock( &p_fifo->lock );
553 while (p_block != NULL)
555 i_size += p_block->i_buffer;
557 *p_fifo->pp_last = p_block;
558 p_fifo->pp_last = &p_block->p_next;
560 p_fifo->i_size += p_block->i_buffer;
562 p_block = p_block->p_next;
565 /* We queued one block: wake up one read-waiting thread */
566 vlc_cond_signal( &p_fifo->wait );
567 vlc_mutex_unlock( &p_fifo->lock );
572 void block_FifoWake( block_fifo_t *p_fifo )
574 vlc_mutex_lock( &p_fifo->lock );
575 if( p_fifo->p_first == NULL )
576 p_fifo->b_force_wake = true;
577 vlc_cond_broadcast( &p_fifo->wait );
578 vlc_mutex_unlock( &p_fifo->lock );
581 block_t *block_FifoGet( block_fifo_t *p_fifo )
587 vlc_mutex_lock( &p_fifo->lock );
588 mutex_cleanup_push( &p_fifo->lock );
590 /* Remember vlc_cond_wait() may cause spurious wakeups
591 * (on both Win32 and POSIX) */
592 while( ( p_fifo->p_first == NULL ) && !p_fifo->b_force_wake )
593 vlc_cond_wait( &p_fifo->wait, &p_fifo->lock );
598 p_fifo->b_force_wake = false;
602 vlc_mutex_unlock( &p_fifo->lock );
606 p_fifo->p_first = b->p_next;
608 p_fifo->i_size -= b->i_buffer;
610 if( p_fifo->p_first == NULL )
612 p_fifo->pp_last = &p_fifo->p_first;
615 /* We don't know how many threads can queue new packets now. */
616 vlc_cond_broadcast( &p_fifo->wait_room );
617 vlc_mutex_unlock( &p_fifo->lock );
623 block_t *block_FifoShow( block_fifo_t *p_fifo )
629 vlc_mutex_lock( &p_fifo->lock );
630 mutex_cleanup_push( &p_fifo->lock );
632 while( p_fifo->p_first == NULL )
633 vlc_cond_wait( &p_fifo->wait, &p_fifo->lock );
641 /* FIXME: not thread-safe */
642 size_t block_FifoSize( const block_fifo_t *p_fifo )
644 return p_fifo->i_size;
647 /* FIXME: not thread-safe */
648 size_t block_FifoCount( const block_fifo_t *p_fifo )
650 return p_fifo->i_depth;