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>
39 #include "vlc_block.h"
42 * @section Block handling functions.
46 * Internal state for heap block.
51 size_t i_allocated_buffer;
52 uint8_t p_allocated_buffer[];
56 static void BlockNoRelease( block_t *b )
58 fprintf( stderr, "block %p has no release callback! This is a bug!\n", b );
63 void block_Init( block_t *restrict b, void *buf, size_t size )
65 /* Fill all fields to their default */
72 b->i_dts = VLC_TS_INVALID;
75 b->pf_release = BlockNoRelease;
79 static void BlockRelease( block_t *p_block )
84 static void BlockMetaCopy( block_t *restrict out, const block_t *in )
86 out->p_next = in->p_next;
87 out->i_nb_samples = in->i_nb_samples;
88 out->i_dts = in->i_dts;
89 out->i_pts = in->i_pts;
90 out->i_flags = in->i_flags;
91 out->i_length = in->i_length;
94 /* Memory alignment (must be a multiple of sizeof(void*) and a power of two) */
95 #define BLOCK_ALIGN 16
96 /* Initial reserved header and footer size (must be multiple of alignment) */
97 #define BLOCK_PADDING 32
98 /* Maximum size of reserved footer before we release with realloc() */
99 #define BLOCK_WASTE_SIZE 2048
101 block_t *block_Alloc( size_t i_size )
103 /* We do only one malloc
104 * TODO: bench if doing 2 malloc but keeping a pool of buffer is better
105 * 2 * BLOCK_PADDING -> pre + post padding
110 #define ALIGN(x) (((x) + BLOCK_ALIGN - 1) & ~(BLOCK_ALIGN - 1))
111 #if 0 /*def HAVE_POSIX_MEMALIGN */
112 /* posix_memalign(,16,) is much slower than malloc() on glibc.
113 * -- Courmisch, September 2009, glibc 2.5 & 2.9 */
114 const size_t i_alloc = ALIGN(sizeof(*p_sys)) + (2 * BLOCK_PADDING)
118 if( posix_memalign( &ptr, BLOCK_ALIGN, i_alloc ) )
122 buf = p_sys->p_allocated_buffer + (-sizeof(*p_sys) & (BLOCK_ALIGN - 1));
125 const size_t i_alloc = sizeof(*p_sys) + BLOCK_ALIGN + (2 * BLOCK_PADDING)
127 p_sys = malloc( i_alloc );
131 buf = (void *)ALIGN((uintptr_t)p_sys->p_allocated_buffer);
134 buf += BLOCK_PADDING;
136 block_Init( &p_sys->self, buf, i_size );
137 p_sys->self.pf_release = BlockRelease;
138 /* Fill opaque data */
139 p_sys->i_allocated_buffer = i_alloc - sizeof(*p_sys);
144 block_t *block_Realloc( block_t *p_block, ssize_t i_prebody, size_t i_body )
146 size_t requested = i_prebody + i_body;
148 /* Corner case: empty block requested */
149 if( i_prebody <= 0 && i_body <= (size_t)(-i_prebody) )
151 block_Release( p_block );
155 if( p_block->pf_release != BlockRelease )
157 /* Special case when pf_release if overloaded
158 * TODO if used one day, then implement it in a smarter way */
159 block_t *p_dup = block_Duplicate( p_block );
160 block_Release( p_block );
167 block_sys_t *p_sys = (block_sys_t *)p_block;
168 uint8_t *p_start = p_sys->p_allocated_buffer;
169 uint8_t *p_end = p_sys->p_allocated_buffer + p_sys->i_allocated_buffer;
171 assert( p_block->p_buffer + p_block->i_buffer <= p_end );
172 assert( p_block->p_buffer >= p_start );
174 /* Corner case: the current payload is discarded completely */
175 if( i_prebody <= 0 && p_block->i_buffer <= (size_t)-i_prebody )
176 p_block->i_buffer = 0; /* discard current payload */
177 if( p_block->i_buffer == 0 )
179 size_t available = p_end - p_start;
181 if( requested <= available )
182 { /* Enough room: recycle buffer */
183 size_t extra = available - requested;
185 p_block->p_buffer = p_start + (extra / 2);
186 p_block->i_buffer = requested;
189 /* Not enough room: allocate a new buffer */
190 block_t *p_rea = block_Alloc( requested );
192 BlockMetaCopy( p_rea, p_block );
193 block_Release( p_block );
197 /* First, shrink payload */
199 /* Pull payload start */
202 assert( p_block->i_buffer >= (size_t)-i_prebody );
203 p_block->p_buffer -= i_prebody;
204 p_block->i_buffer += i_prebody;
209 /* Trim payload end */
210 if( p_block->i_buffer > i_body )
211 p_block->i_buffer = i_body;
213 /* Second, reallocate the buffer if we lack space. This is done now to
214 * minimize the payload size for memory copy. */
215 assert( i_prebody >= 0 );
216 if( (size_t)(p_block->p_buffer - p_start) < (size_t)i_prebody
217 || (size_t)(p_end - p_block->p_buffer) < i_body )
219 block_t *p_rea = block_Alloc( requested );
222 BlockMetaCopy( p_rea, p_block );
223 p_rea->p_buffer += i_prebody;
224 p_rea->i_buffer -= i_prebody;
225 memcpy( p_rea->p_buffer, p_block->p_buffer, p_block->i_buffer );
227 block_Release( p_block );
233 /* We have a very large reserved footer now? Release some of it.
234 * XXX it might not preserve the alignment of p_buffer */
235 if( p_end - (p_block->p_buffer + i_body) > BLOCK_WASTE_SIZE )
237 block_t *p_rea = block_Alloc( requested );
240 BlockMetaCopy( p_rea, p_block );
241 p_rea->p_buffer += i_prebody;
242 p_rea->i_buffer -= i_prebody;
243 memcpy( p_rea->p_buffer, p_block->p_buffer, p_block->i_buffer );
244 block_Release( p_block );
249 /* NOTE: p_start and p_end are corrupted from this point */
251 /* Third, expand payload */
253 /* Push payload start */
256 p_block->p_buffer -= i_prebody;
257 p_block->i_buffer += i_prebody;
262 /* Expand payload to requested size */
263 p_block->i_buffer = i_body;
275 static void block_heap_Release (block_t *self)
277 block_heap_t *block = (block_heap_t *)self;
284 * Creates a block from a heap allocation.
285 * This is provided by LibVLC so that manually heap-allocated blocks can safely
286 * be deallocated even after the origin plugin has been unloaded from memory.
288 * When block_Release() is called, VLC will free() the specified pointer.
290 * @param ptr base address of the heap allocation (will be free()'d)
291 * @param addr base address of the useful buffer data
292 * @param length bytes length of the useful buffer data
293 * @return NULL in case of error (ptr free()'d in that case), or a valid
296 block_t *block_heap_Alloc (void *ptr, void *addr, size_t length)
298 block_heap_t *block = malloc (sizeof (*block));
305 block_Init (&block->self, (uint8_t *)addr, length);
306 block->self.pf_release = block_heap_Release;
312 # include <sys/mman.h>
314 typedef struct block_mmap_t
321 static void block_mmap_Release (block_t *block)
323 block_mmap_t *p_sys = (block_mmap_t *)block;
325 munmap (p_sys->base_addr, p_sys->length);
330 * Creates a block from a virtual address memory mapping (mmap).
331 * This is provided by LibVLC so that mmap blocks can safely be deallocated
332 * even after the allocating plugin has been unloaded from memory.
334 * @param addr base address of the mapping (as returned by mmap)
335 * @param length length (bytes) of the mapping (as passed to mmap)
336 * @return NULL if addr is MAP_FAILED, or an error occurred (in the later
337 * case, munmap(addr, length) is invoked before returning).
339 block_t *block_mmap_Alloc (void *addr, size_t length)
341 if (addr == MAP_FAILED)
344 block_mmap_t *block = malloc (sizeof (*block));
347 munmap (addr, length);
351 block_Init (&block->self, (uint8_t *)addr, length);
352 block->self.pf_release = block_mmap_Release;
353 block->base_addr = addr;
354 block->length = length;
358 block_t *block_mmap_Alloc (void *addr, size_t length)
360 (void)addr; (void)length; return NULL;
368 # define _get_osfhandle(a) ((long) (a))
372 ssize_t pread (int fd, void *buf, size_t count, off_t offset)
374 HANDLE handle = (HANDLE)(intptr_t)_get_osfhandle (fd);
375 if (handle == INVALID_HANDLE_VALUE)
378 OVERLAPPED olap; olap.Offset = offset; olap.OffsetHigh = (offset >> 32);
380 /* This braindead API will override the file pointer even if we specify
381 * an explicit read offset... So do not expect this to mix well with
382 * regular read() calls. */
383 if (ReadFile (handle, buf, count, &written, &olap))
387 #elif !defined( HAVE_PREAD )
389 ssize_t pread(int fd, const void * buf, size_t size, off_t offset) {
392 if ((offs0 = lseek(fd, 0, SEEK_CUR)) == (off_t)-1) return -1;
393 if (lseek(fd, offset, SEEK_SET) == (off_t)-1) return -1;
394 rd = read(fd, (void *)buf, size);
395 if (lseek(fd, offs0, SEEK_SET) == (off_t)-1) return -1;
400 ssize_t pwrite(int fd, const void * buf, size_t size, off_t offset) {
403 if ((offs0 = lseek(fd, 0, SEEK_CUR)) == (off_t)-1) return -1;
404 if (lseek(fd, offset, SEEK_SET) == (off_t)-1) return -1;
405 wr = write(fd, (void *)buf, size);
406 if (lseek(fd, offs0, SEEK_SET) == (off_t)-1) return -1;
412 * Loads a file into a block of memory. If possible a private file mapping is
413 * created. Otherwise, the file is read normally. On 32-bits platforms, this
414 * function will not work for very large files, due to memory space
415 * constraints. Cancellation point.
417 * @param fd file descriptor to load from
418 * @return a new block with the file content at p_buffer, and file length at
419 * i_buffer (release it with block_Release()), or NULL upon error (see errno).
421 block_t *block_File (int fd)
426 /* First, get the file size */
430 /* st_size is meaningful for regular files, shared memory and typed memory.
431 * It's also meaning for symlinks, but that's not possible with fstat().
432 * In other cases, it's undefined, and we should really not go further. */
434 # define S_TYPEISSHM( buf ) (0)
436 if (S_ISDIR (st.st_mode))
441 if (!S_ISREG (st.st_mode) && !S_TYPEISSHM (&st))
447 /* Prevent an integer overflow in mmap() and malloc() */
448 if (st.st_size >= SIZE_MAX)
453 length = (size_t)st.st_size;
460 addr = mmap (NULL, length, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
461 if (addr != MAP_FAILED)
462 return block_mmap_Alloc (addr, length);
466 /* If mmap() is not implemented by the OS _or_ the filesystem... */
467 block_t *block = block_Alloc (length);
470 block_cleanup_push (block);
472 for (size_t i = 0; i < length;)
474 ssize_t len = pread (fd, block->p_buffer + i, length - i, i);
477 block_Release (block);
488 * @section Thread-safe block queue functions
492 * Internal state for block queues
496 vlc_mutex_t lock; /* fifo data lock */
497 vlc_cond_t wait; /**< Wait for data */
498 vlc_cond_t wait_room; /**< Wait for queue depth to shrink */
507 block_fifo_t *block_FifoNew( void )
509 block_fifo_t *p_fifo = malloc( sizeof( block_fifo_t ) );
513 vlc_mutex_init( &p_fifo->lock );
514 vlc_cond_init( &p_fifo->wait );
515 vlc_cond_init( &p_fifo->wait_room );
516 p_fifo->p_first = NULL;
517 p_fifo->pp_last = &p_fifo->p_first;
518 p_fifo->i_depth = p_fifo->i_size = 0;
519 p_fifo->b_force_wake = false;
524 void block_FifoRelease( block_fifo_t *p_fifo )
526 block_FifoEmpty( p_fifo );
527 vlc_cond_destroy( &p_fifo->wait_room );
528 vlc_cond_destroy( &p_fifo->wait );
529 vlc_mutex_destroy( &p_fifo->lock );
533 void block_FifoEmpty( block_fifo_t *p_fifo )
537 vlc_mutex_lock( &p_fifo->lock );
538 block = p_fifo->p_first;
541 p_fifo->i_depth = p_fifo->i_size = 0;
542 p_fifo->p_first = NULL;
543 p_fifo->pp_last = &p_fifo->p_first;
545 vlc_cond_broadcast( &p_fifo->wait_room );
546 vlc_mutex_unlock( &p_fifo->lock );
548 while (block != NULL)
553 block_Release (block);
559 * Wait until the FIFO gets below a certain size (if needed).
561 * Note that if more than one thread writes to the FIFO, you cannot assume that
562 * the FIFO is actually below the requested size upon return (since another
563 * thread could have refilled it already). This is typically not an issue, as
564 * this function is meant for (relaxed) congestion control.
566 * This function may be a cancellation point and it is cancel-safe.
568 * @param fifo queue to wait on
569 * @param max_depth wait until the queue has no more than this many blocks
570 * (use SIZE_MAX to ignore this constraint)
571 * @param max_size wait until the queue has no more than this many bytes
572 * (use SIZE_MAX to ignore this constraint)
575 void block_FifoPace (block_fifo_t *fifo, size_t max_depth, size_t max_size)
579 vlc_mutex_lock (&fifo->lock);
580 while ((fifo->i_depth > max_depth) || (fifo->i_size > max_size))
582 mutex_cleanup_push (&fifo->lock);
583 vlc_cond_wait (&fifo->wait_room, &fifo->lock);
586 vlc_mutex_unlock (&fifo->lock);
590 * Immediately queue one block at the end of a FIFO.
592 * @param block head of a block list to queue (may be NULL)
593 * @return total number of bytes appended to the queue
595 size_t block_FifoPut( block_fifo_t *p_fifo, block_t *p_block )
597 size_t i_size = 0, i_depth = 0;
602 for (p_last = p_block; ; p_last = p_last->p_next)
604 i_size += p_last->i_buffer;
610 vlc_mutex_lock (&p_fifo->lock);
611 *p_fifo->pp_last = p_block;
612 p_fifo->pp_last = &p_last->p_next;
613 p_fifo->i_depth += i_depth;
614 p_fifo->i_size += i_size;
615 /* We queued at least one block: wake up one read-waiting thread */
616 vlc_cond_signal( &p_fifo->wait );
617 vlc_mutex_unlock( &p_fifo->lock );
622 void block_FifoWake( block_fifo_t *p_fifo )
624 vlc_mutex_lock( &p_fifo->lock );
625 if( p_fifo->p_first == NULL )
626 p_fifo->b_force_wake = true;
627 vlc_cond_broadcast( &p_fifo->wait );
628 vlc_mutex_unlock( &p_fifo->lock );
632 * Dequeue the first block from the FIFO. If necessary, wait until there is
633 * one block in the queue. This function is (always) cancellation point.
635 * @return a valid block, or NULL if block_FifoWake() was called.
637 block_t *block_FifoGet( block_fifo_t *p_fifo )
643 vlc_mutex_lock( &p_fifo->lock );
644 mutex_cleanup_push( &p_fifo->lock );
646 /* Remember vlc_cond_wait() may cause spurious wakeups
647 * (on both Win32 and POSIX) */
648 while( ( p_fifo->p_first == NULL ) && !p_fifo->b_force_wake )
649 vlc_cond_wait( &p_fifo->wait, &p_fifo->lock );
654 p_fifo->b_force_wake = false;
658 vlc_mutex_unlock( &p_fifo->lock );
662 p_fifo->p_first = b->p_next;
664 p_fifo->i_size -= b->i_buffer;
666 if( p_fifo->p_first == NULL )
668 p_fifo->pp_last = &p_fifo->p_first;
671 /* We don't know how many threads can queue new packets now. */
672 vlc_cond_broadcast( &p_fifo->wait_room );
673 vlc_mutex_unlock( &p_fifo->lock );
680 * Peeks the first block in the FIFO.
681 * If necessary, wait until there is one block.
682 * This function is (always) a cancellation point.
684 * @warning This function leaves the block in the FIFO.
685 * You need to protect against concurrent threads who could dequeue the block.
686 * Preferrably, there should be only one thread reading from the FIFO.
688 * @return a valid block.
690 block_t *block_FifoShow( block_fifo_t *p_fifo )
696 vlc_mutex_lock( &p_fifo->lock );
697 mutex_cleanup_push( &p_fifo->lock );
699 while( p_fifo->p_first == NULL )
700 vlc_cond_wait( &p_fifo->wait, &p_fifo->lock );
708 /* FIXME: not thread-safe */
709 size_t block_FifoSize( const block_fifo_t *p_fifo )
711 return p_fifo->i_size;
714 /* FIXME: not thread-safe */
715 size_t block_FifoCount( const block_fifo_t *p_fifo )
717 return p_fifo->i_depth;