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>
35 #include "vlc_block.h"
38 * @section Block handling functions.
42 * Internal state for heap block.
47 size_t i_allocated_buffer;
48 uint8_t p_allocated_buffer[];
52 static void BlockNoRelease( block_t *b )
54 fprintf( stderr, "block %p has no release callback! This is a bug!\n", b );
59 void block_Init( block_t *restrict b, void *buf, size_t size )
61 /* Fill all fields to their default */
68 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_nb_samples = in->i_nb_samples;
84 out->i_dts = in->i_dts;
85 out->i_pts = in->i_pts;
86 out->i_flags = in->i_flags;
87 out->i_length = in->i_length;
90 /* Memory alignment (must be a multiple of sizeof(void*) and a power of two) */
91 #define BLOCK_ALIGN 16
92 /* Initial reserved header and footer size (must be multiple of alignment) */
93 #define BLOCK_PADDING 32
94 /* Maximum size of reserved footer before we release with realloc() */
95 #define BLOCK_WASTE_SIZE 2048
97 block_t *block_Alloc( size_t i_size )
99 /* We do only one malloc
100 * TODO: bench if doing 2 malloc but keeping a pool of buffer is better
101 * 2 * BLOCK_PADDING -> pre + post padding
106 #define ALIGN(x) (((x) + BLOCK_ALIGN - 1) & ~(BLOCK_ALIGN - 1))
107 #if 0 /*def HAVE_POSIX_MEMALIGN */
108 /* posix_memalign(,16,) is much slower than malloc() on glibc.
109 * -- Courmisch, September 2009, glibc 2.5 & 2.9 */
110 const size_t i_alloc = ALIGN(sizeof(*p_sys)) + (2 * BLOCK_PADDING)
114 if( posix_memalign( &ptr, BLOCK_ALIGN, i_alloc ) )
118 buf = p_sys->p_allocated_buffer + (-sizeof(*p_sys) & (BLOCK_ALIGN - 1));
121 const size_t i_alloc = sizeof(*p_sys) + BLOCK_ALIGN + (2 * BLOCK_PADDING)
123 p_sys = malloc( i_alloc );
127 buf = (void *)ALIGN((uintptr_t)p_sys->p_allocated_buffer);
130 buf += BLOCK_PADDING;
132 block_Init( &p_sys->self, buf, i_size );
133 p_sys->self.pf_release = BlockRelease;
134 /* Fill opaque data */
135 p_sys->i_allocated_buffer = i_alloc - sizeof(*p_sys);
140 block_t *block_Realloc( block_t *p_block, ssize_t i_prebody, size_t i_body )
142 size_t requested = i_prebody + i_body;
144 /* Corner case: empty block requested */
145 if( i_prebody <= 0 && i_body <= (size_t)(-i_prebody) )
147 block_Release( p_block );
151 if( p_block->pf_release != BlockRelease )
153 /* Special case when pf_release if overloaded
154 * TODO if used one day, then implement it in a smarter way */
155 block_t *p_dup = block_Duplicate( p_block );
156 block_Release( p_block );
163 block_sys_t *p_sys = (block_sys_t *)p_block;
164 uint8_t *p_start = p_sys->p_allocated_buffer;
165 uint8_t *p_end = p_sys->p_allocated_buffer + p_sys->i_allocated_buffer;
167 assert( p_block->p_buffer + p_block->i_buffer <= p_end );
168 assert( p_block->p_buffer >= p_start );
170 /* Corner case: the current payload is discarded completely */
171 if( i_prebody <= 0 && p_block->i_buffer <= (size_t)-i_prebody )
172 p_block->i_buffer = 0; /* discard current payload */
173 if( p_block->i_buffer == 0 )
175 size_t available = p_end - p_start;
177 if( requested <= available )
178 { /* Enough room: recycle buffer */
179 size_t extra = available - requested;
181 p_block->p_buffer = p_start + (extra / 2);
182 p_block->i_buffer = requested;
185 /* Not enough room: allocate a new buffer */
186 block_t *p_rea = block_Alloc( requested );
188 BlockMetaCopy( p_rea, p_block );
189 block_Release( p_block );
193 /* First, shrink payload */
195 /* Pull payload start */
198 assert( p_block->i_buffer >= (size_t)-i_prebody );
199 p_block->p_buffer -= i_prebody;
200 p_block->i_buffer += i_prebody;
205 /* Trim payload end */
206 if( p_block->i_buffer > i_body )
207 p_block->i_buffer = i_body;
209 /* Second, reallocate the buffer if we lack space. This is done now to
210 * minimize the payload size for memory copy. */
211 assert( i_prebody >= 0 );
212 if( (size_t)(p_block->p_buffer - p_start) < (size_t)i_prebody
213 || (size_t)(p_end - p_block->p_buffer) < i_body )
215 block_t *p_rea = block_Alloc( requested );
218 BlockMetaCopy( p_rea, p_block );
219 p_rea->p_buffer += i_prebody;
220 p_rea->i_buffer -= i_prebody;
221 memcpy( p_rea->p_buffer, p_block->p_buffer, p_block->i_buffer );
223 block_Release( p_block );
229 /* We have a very large reserved footer now? Release some of it.
230 * XXX it might not preserve the alignment of p_buffer */
231 if( p_end - (p_block->p_buffer + i_body) > BLOCK_WASTE_SIZE )
233 block_t *p_rea = block_Alloc( requested );
236 BlockMetaCopy( p_rea, p_block );
237 p_rea->p_buffer += i_prebody;
238 p_rea->i_buffer -= i_prebody;
239 memcpy( p_rea->p_buffer, p_block->p_buffer, p_block->i_buffer );
240 block_Release( p_block );
245 /* NOTE: p_start and p_end are corrupted from this point */
247 /* Third, expand payload */
249 /* Push payload start */
252 p_block->p_buffer -= i_prebody;
253 p_block->i_buffer += i_prebody;
258 /* Expand payload to requested size */
259 p_block->i_buffer = i_body;
271 static void block_heap_Release (block_t *self)
273 block_heap_t *block = (block_heap_t *)self;
280 * Creates a block from a heap allocation.
281 * This is provided by LibVLC so that manually heap-allocated blocks can safely
282 * be deallocated even after the origin plugin has been unloaded from memory.
284 * When block_Release() is called, VLC will free() the specified pointer.
286 * @param ptr base address of the heap allocation (will be free()'d)
287 * @param addr base address of the useful buffer data
288 * @param length bytes length of the useful buffer data
289 * @return NULL in case of error (ptr free()'d in that case), or a valid
292 block_t *block_heap_Alloc (void *ptr, void *addr, size_t length)
294 block_heap_t *block = malloc (sizeof (*block));
301 block_Init (&block->self, (uint8_t *)addr, length);
302 block->self.pf_release = block_heap_Release;
308 # include <sys/mman.h>
310 typedef struct block_mmap_t
317 static void block_mmap_Release (block_t *block)
319 block_mmap_t *p_sys = (block_mmap_t *)block;
321 munmap (p_sys->base_addr, p_sys->length);
326 * Creates a block from a virtual address memory mapping (mmap).
327 * This is provided by LibVLC so that mmap blocks can safely be deallocated
328 * even after the allocating plugin has been unloaded from memory.
330 * @param addr base address of the mapping (as returned by mmap)
331 * @param length length (bytes) of the mapping (as passed to mmap)
332 * @return NULL if addr is MAP_FAILED, or an error occurred (in the later
333 * case, munmap(addr, length) is invoked before returning).
335 block_t *block_mmap_Alloc (void *addr, size_t length)
337 if (addr == MAP_FAILED)
340 block_mmap_t *block = malloc (sizeof (*block));
343 munmap (addr, length);
347 block_Init (&block->self, (uint8_t *)addr, length);
348 block->self.pf_release = block_mmap_Release;
349 block->base_addr = addr;
350 block->length = length;
354 block_t *block_mmap_Alloc (void *addr, size_t length)
356 (void)addr; (void)length; return NULL;
364 # define _get_osfhandle(a) ((long) (a))
368 ssize_t pread (int fd, void *buf, size_t count, off_t offset)
370 HANDLE handle = (HANDLE)(intptr_t)_get_osfhandle (fd);
371 if (handle == INVALID_HANDLE_VALUE)
374 OVERLAPPED olap; olap.Offset = offset; olap.OffsetHigh = (offset >> 32);
376 /* This braindead API will override the file pointer even if we specify
377 * an explicit read offset... So do not expect this to mix well with
378 * regular read() calls. */
379 if (ReadFile (handle, buf, count, &written, &olap))
383 #elif !defined( HAVE_PREAD )
385 ssize_t pread(int fd, const void * buf, size_t size, off_t offset) {
388 if ((offs0 = lseek(fd, 0, SEEK_CUR)) == (off_t)-1) return -1;
389 if (lseek(fd, offset, SEEK_SET) == (off_t)-1) return -1;
390 rd = read(fd, (void *)buf, size);
391 if (lseek(fd, offs0, SEEK_SET) == (off_t)-1) return -1;
396 ssize_t pwrite(int fd, const void * buf, size_t size, off_t offset) {
399 if ((offs0 = lseek(fd, 0, SEEK_CUR)) == (off_t)-1) return -1;
400 if (lseek(fd, offset, SEEK_SET) == (off_t)-1) return -1;
401 wr = write(fd, (void *)buf, size);
402 if (lseek(fd, offs0, SEEK_SET) == (off_t)-1) return -1;
408 * Loads a file into a block of memory. If possible a private file mapping is
409 * created. Otherwise, the file is read normally. On 32-bits platforms, this
410 * function will not work for very large files, due to memory space
411 * constraints. Cancellation point.
413 * @param fd file descriptor to load from
414 * @return a new block with the file content at p_buffer, and file length at
415 * i_buffer (release it with block_Release()), or NULL upon error (see errno).
417 block_t *block_File (int fd)
422 /* First, get the file size */
426 /* st_size is meaningful for regular files, shared memory and typed memory.
427 * It's also meaning for symlinks, but that's not possible with fstat().
428 * In other cases, it's undefined, and we should really not go further. */
430 # define S_TYPEISSHM( buf ) (0)
432 if (S_ISDIR (st.st_mode))
437 if (!S_ISREG (st.st_mode) && !S_TYPEISSHM (&st))
443 /* Prevent an integer overflow in mmap() and malloc() */
444 if (st.st_size >= SIZE_MAX)
449 length = (size_t)st.st_size;
456 addr = mmap (NULL, length, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
457 if (addr != MAP_FAILED)
458 return block_mmap_Alloc (addr, length);
462 /* If mmap() is not implemented by the OS _or_ the filesystem... */
463 block_t *block = block_Alloc (length);
466 block_cleanup_push (block);
468 for (size_t i = 0; i < length;)
470 ssize_t len = pread (fd, block->p_buffer + i, length - i, i);
473 block_Release (block);
484 * @section Thread-safe block queue functions
488 * Internal state for block queues
492 vlc_mutex_t lock; /* fifo data lock */
493 vlc_cond_t wait; /**< Wait for data */
494 vlc_cond_t wait_room; /**< Wait for queue depth to shrink */
503 block_fifo_t *block_FifoNew( void )
505 block_fifo_t *p_fifo = malloc( sizeof( block_fifo_t ) );
509 vlc_mutex_init( &p_fifo->lock );
510 vlc_cond_init( &p_fifo->wait );
511 vlc_cond_init( &p_fifo->wait_room );
512 p_fifo->p_first = NULL;
513 p_fifo->pp_last = &p_fifo->p_first;
514 p_fifo->i_depth = p_fifo->i_size = 0;
515 p_fifo->b_force_wake = false;
520 void block_FifoRelease( block_fifo_t *p_fifo )
522 block_FifoEmpty( p_fifo );
523 vlc_cond_destroy( &p_fifo->wait_room );
524 vlc_cond_destroy( &p_fifo->wait );
525 vlc_mutex_destroy( &p_fifo->lock );
529 void block_FifoEmpty( block_fifo_t *p_fifo )
533 vlc_mutex_lock( &p_fifo->lock );
534 block = p_fifo->p_first;
537 p_fifo->i_depth = p_fifo->i_size = 0;
538 p_fifo->p_first = NULL;
539 p_fifo->pp_last = &p_fifo->p_first;
541 vlc_cond_broadcast( &p_fifo->wait_room );
542 vlc_mutex_unlock( &p_fifo->lock );
544 while (block != NULL)
549 block_Release (block);
555 * Wait until the FIFO gets below a certain size (if needed).
557 * Note that if more than one thread writes to the FIFO, you cannot assume that
558 * the FIFO is actually below the requested size upon return (since another
559 * thread could have refilled it already). This is typically not an issue, as
560 * this function is meant for (relaxed) congestion control.
562 * This function may be a cancellation point and it is cancel-safe.
564 * @param fifo queue to wait on
565 * @param max_depth wait until the queue has no more than this many blocks
566 * (use SIZE_MAX to ignore this constraint)
567 * @param max_size wait until the queue has no more than this many bytes
568 * (use SIZE_MAX to ignore this constraint)
571 void block_FifoPace (block_fifo_t *fifo, size_t max_depth, size_t max_size)
575 vlc_mutex_lock (&fifo->lock);
576 while ((fifo->i_depth > max_depth) || (fifo->i_size > max_size))
578 mutex_cleanup_push (&fifo->lock);
579 vlc_cond_wait (&fifo->wait_room, &fifo->lock);
582 vlc_mutex_unlock (&fifo->lock);
586 * Immediately queue one block at the end of a FIFO.
588 * @param block head of a block list to queue (may be NULL)
589 * @return total number of bytes appended to the queue
591 size_t block_FifoPut( block_fifo_t *p_fifo, block_t *p_block )
593 size_t i_size = 0, i_depth = 0;
598 for (p_last = p_block; ; p_last = p_last->p_next)
600 i_size += p_last->i_buffer;
606 vlc_mutex_lock (&p_fifo->lock);
607 *p_fifo->pp_last = p_block;
608 p_fifo->pp_last = &p_last->p_next;
609 p_fifo->i_depth += i_depth;
610 p_fifo->i_size += i_size;
611 /* We queued at least one block: wake up one read-waiting thread */
612 vlc_cond_signal( &p_fifo->wait );
613 vlc_mutex_unlock( &p_fifo->lock );
618 void block_FifoWake( block_fifo_t *p_fifo )
620 vlc_mutex_lock( &p_fifo->lock );
621 if( p_fifo->p_first == NULL )
622 p_fifo->b_force_wake = true;
623 vlc_cond_broadcast( &p_fifo->wait );
624 vlc_mutex_unlock( &p_fifo->lock );
628 * Dequeue the first block from the FIFO. If necessary, wait until there is
629 * one block in the queue. This function is (always) cancellation point.
631 * @return a valid block, or NULL if block_FifoWake() was called.
633 block_t *block_FifoGet( block_fifo_t *p_fifo )
639 vlc_mutex_lock( &p_fifo->lock );
640 mutex_cleanup_push( &p_fifo->lock );
642 /* Remember vlc_cond_wait() may cause spurious wakeups
643 * (on both Win32 and POSIX) */
644 while( ( p_fifo->p_first == NULL ) && !p_fifo->b_force_wake )
645 vlc_cond_wait( &p_fifo->wait, &p_fifo->lock );
650 p_fifo->b_force_wake = false;
654 vlc_mutex_unlock( &p_fifo->lock );
658 p_fifo->p_first = b->p_next;
660 p_fifo->i_size -= b->i_buffer;
662 if( p_fifo->p_first == NULL )
664 p_fifo->pp_last = &p_fifo->p_first;
667 /* We don't know how many threads can queue new packets now. */
668 vlc_cond_broadcast( &p_fifo->wait_room );
669 vlc_mutex_unlock( &p_fifo->lock );
676 * Peeks the first block in the FIFO.
677 * If necessary, wait until there is one block.
678 * This function is (always) a cancellation point.
680 * @warning This function leaves the block in the FIFO.
681 * You need to protect against concurrent threads who could dequeue the block.
682 * Preferrably, there should be only one thread reading from the FIFO.
684 * @return a valid block.
686 block_t *block_FifoShow( block_fifo_t *p_fifo )
692 vlc_mutex_lock( &p_fifo->lock );
693 mutex_cleanup_push( &p_fifo->lock );
695 while( p_fifo->p_first == NULL )
696 vlc_cond_wait( &p_fifo->wait, &p_fifo->lock );
704 /* FIXME: not thread-safe */
705 size_t block_FifoSize( const block_fifo_t *p_fifo )
707 return p_fifo->i_size;
710 /* FIXME: not thread-safe */
711 size_t block_FifoCount( const block_fifo_t *p_fifo )
713 return p_fifo->i_depth;