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 block_sys_t *p_sys = (block_sys_t *)p_block;
143 size_t requested = i_prebody + i_body;
145 /* Corner case: empty block requested */
146 if( i_prebody <= 0 && i_body <= (size_t)(-i_prebody) )
148 block_Release( p_block );
152 if( p_block->pf_release != BlockRelease )
154 /* Special case when pf_release if overloaded
155 * TODO if used one day, then implement it in a smarter way */
156 block_t *p_dup = block_Duplicate( p_block );
157 block_Release( p_block );
162 p_sys = (block_sys_t *)p_block;
165 uint8_t *p_start = p_sys->p_allocated_buffer;
166 uint8_t *p_end = p_sys->p_allocated_buffer + p_sys->i_allocated_buffer;
168 assert( p_block->p_buffer + p_block->i_buffer <= p_end );
169 assert( p_block->p_buffer >= p_start );
171 /* Corner case: the current payload is discarded completely */
172 if( i_prebody <= 0 && p_block->i_buffer <= (size_t)-i_prebody )
173 p_block->i_buffer = 0; /* discard current payload */
174 if( p_block->i_buffer == 0 )
176 size_t available = p_end - p_start;
178 if( requested <= available )
179 { /* Enough room: recycle buffer */
180 size_t extra = available - requested;
182 p_block->p_buffer = p_start + (extra / 2);
183 p_block->i_buffer = requested;
186 /* Not enough room: allocate a new buffer */
187 block_t *p_rea = block_Alloc( requested );
189 BlockMetaCopy( p_rea, p_block );
190 block_Release( p_block );
194 /* First, shrink payload */
196 /* Pull payload start */
199 assert( p_block->i_buffer >= (size_t)-i_prebody );
200 p_block->p_buffer -= i_prebody;
201 p_block->i_buffer += i_prebody;
206 /* Trim payload end */
207 if( p_block->i_buffer > i_body )
208 p_block->i_buffer = i_body;
210 /* Second, reallocate the buffer if we lack space. This is done now to
211 * minimize the payload size for memory copy. */
212 assert( i_prebody >= 0 );
213 if( (size_t)(p_block->p_buffer - p_start) < (size_t)i_prebody
214 || (size_t)(p_end - p_block->p_buffer) < i_body )
216 block_t *p_rea = block_Alloc( requested );
219 BlockMetaCopy( p_rea, p_block );
220 p_rea->p_buffer += i_prebody;
221 p_rea->i_buffer -= i_prebody;
222 memcpy( p_rea->p_buffer, p_block->p_buffer, p_block->i_buffer );
224 block_Release( p_block );
230 /* We have a very large reserved footer now? Release some of it.
231 * XXX it might not preserve the alignment of p_buffer */
232 if( p_end - (p_block->p_buffer + i_body) > BLOCK_WASTE_SIZE )
234 block_t *p_rea = block_Alloc( requested );
237 BlockMetaCopy( p_rea, p_block );
238 p_rea->p_buffer += i_prebody;
239 p_rea->i_buffer -= i_prebody;
240 memcpy( p_rea->p_buffer, p_block->p_buffer, p_block->i_buffer );
241 block_Release( p_block );
246 /* NOTE: p_start and p_end are corrupted from this point */
248 /* Third, expand payload */
250 /* Push payload start */
253 p_block->p_buffer -= i_prebody;
254 p_block->i_buffer += i_prebody;
259 /* Expand payload to requested size */
260 p_block->i_buffer = i_body;
272 static void block_heap_Release (block_t *self)
274 block_heap_t *block = (block_heap_t *)self;
281 * Creates a block from a heap allocation.
282 * This is provided by LibVLC so that manually heap-allocated blocks can safely
283 * be deallocated even after the origin plugin has been unloaded from memory.
285 * When block_Release() is called, VLC will free() the specified pointer.
287 * @param ptr base address of the heap allocation (will be free()'d)
288 * @param addr base address of the useful buffer data
289 * @param length bytes length of the useful buffer data
290 * @return NULL in case of error (ptr free()'d in that case), or a valid
293 block_t *block_heap_Alloc (void *ptr, void *addr, size_t length)
295 block_heap_t *block = malloc (sizeof (*block));
302 block_Init (&block->self, (uint8_t *)addr, length);
303 block->self.pf_release = block_heap_Release;
309 # include <sys/mman.h>
311 typedef struct block_mmap_t
318 static void block_mmap_Release (block_t *block)
320 block_mmap_t *p_sys = (block_mmap_t *)block;
322 munmap (p_sys->base_addr, p_sys->length);
327 * Creates a block from a virtual address memory mapping (mmap).
328 * This is provided by LibVLC so that mmap blocks can safely be deallocated
329 * even after the allocating plugin has been unloaded from memory.
331 * @param addr base address of the mapping (as returned by mmap)
332 * @param length length (bytes) of the mapping (as passed to mmap)
333 * @return NULL if addr is MAP_FAILED, or an error occurred (in the later
334 * case, munmap(addr, length) is invoked before returning).
336 block_t *block_mmap_Alloc (void *addr, size_t length)
338 if (addr == MAP_FAILED)
341 block_mmap_t *block = malloc (sizeof (*block));
344 munmap (addr, length);
348 block_Init (&block->self, (uint8_t *)addr, length);
349 block->self.pf_release = block_mmap_Release;
350 block->base_addr = addr;
351 block->length = length;
355 block_t *block_mmap_Alloc (void *addr, size_t length)
357 (void)addr; (void)length; return NULL;
365 # define _get_osfhandle(a) ((long) (a))
369 ssize_t pread (int fd, void *buf, size_t count, off_t offset)
371 HANDLE handle = (HANDLE)(intptr_t)_get_osfhandle (fd);
372 if (handle == INVALID_HANDLE_VALUE)
375 OVERLAPPED olap; olap.Offset = offset; olap.OffsetHigh = (offset >> 32);
377 /* This braindead API will override the file pointer even if we specify
378 * an explicit read offset... So do not expect this to mix well with
379 * regular read() calls. */
380 if (ReadFile (handle, buf, count, &written, &olap))
384 #elif !defined( HAVE_PREAD )
386 ssize_t pread(int fd, const void * buf, size_t size, off_t offset) {
389 if ((offs0 = lseek(fd, 0, SEEK_CUR)) == (off_t)-1) return -1;
390 if (lseek(fd, offset, SEEK_SET) == (off_t)-1) return -1;
391 rd = read(fd, (void *)buf, size);
392 if (lseek(fd, offs0, SEEK_SET) == (off_t)-1) return -1;
397 ssize_t pwrite(int fd, const void * buf, size_t size, off_t offset) {
400 if ((offs0 = lseek(fd, 0, SEEK_CUR)) == (off_t)-1) return -1;
401 if (lseek(fd, offset, SEEK_SET) == (off_t)-1) return -1;
402 wr = write(fd, (void *)buf, size);
403 if (lseek(fd, offs0, SEEK_SET) == (off_t)-1) return -1;
409 * Loads a file into a block of memory. If possible a private file mapping is
410 * created. Otherwise, the file is read normally. On 32-bits platforms, this
411 * function will not work for very large files, due to memory space
412 * constraints. Cancellation point.
414 * @param fd file descriptor to load from
415 * @return a new block with the file content at p_buffer, and file length at
416 * i_buffer (release it with block_Release()), or NULL upon error (see errno).
418 block_t *block_File (int fd)
423 /* First, get the file size */
427 /* st_size is meaningful for regular files, shared memory and typed memory.
428 * It's also meaning for symlinks, but that's not possible with fstat().
429 * In other cases, it's undefined, and we should really not go further. */
431 # define S_TYPEISSHM( buf ) (0)
433 if (S_ISDIR (st.st_mode))
438 if (!S_ISREG (st.st_mode) && !S_TYPEISSHM (&st))
444 /* Prevent an integer overflow in mmap() and malloc() */
445 if (st.st_size >= SIZE_MAX)
450 length = (size_t)st.st_size;
457 addr = mmap (NULL, length, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
458 if (addr != MAP_FAILED)
459 return block_mmap_Alloc (addr, length);
463 /* If mmap() is not implemented by the OS _or_ the filesystem... */
464 block_t *block = block_Alloc (length);
467 block_cleanup_push (block);
469 for (size_t i = 0; i < length;)
471 ssize_t len = pread (fd, block->p_buffer + i, length - i, i);
474 block_Release (block);
485 * @section Thread-safe block queue functions
489 * Internal state for block queues
493 vlc_mutex_t lock; /* fifo data lock */
494 vlc_cond_t wait; /**< Wait for data */
495 vlc_cond_t wait_room; /**< Wait for queue depth to shrink */
504 block_fifo_t *block_FifoNew( void )
506 block_fifo_t *p_fifo = malloc( sizeof( block_fifo_t ) );
510 vlc_mutex_init( &p_fifo->lock );
511 vlc_cond_init( &p_fifo->wait );
512 vlc_cond_init( &p_fifo->wait_room );
513 p_fifo->p_first = NULL;
514 p_fifo->pp_last = &p_fifo->p_first;
515 p_fifo->i_depth = p_fifo->i_size = 0;
516 p_fifo->b_force_wake = false;
521 void block_FifoRelease( block_fifo_t *p_fifo )
523 block_FifoEmpty( p_fifo );
524 vlc_cond_destroy( &p_fifo->wait_room );
525 vlc_cond_destroy( &p_fifo->wait );
526 vlc_mutex_destroy( &p_fifo->lock );
530 void block_FifoEmpty( block_fifo_t *p_fifo )
534 vlc_mutex_lock( &p_fifo->lock );
535 block = p_fifo->p_first;
538 p_fifo->i_depth = p_fifo->i_size = 0;
539 p_fifo->p_first = NULL;
540 p_fifo->pp_last = &p_fifo->p_first;
542 vlc_cond_broadcast( &p_fifo->wait_room );
543 vlc_mutex_unlock( &p_fifo->lock );
545 while (block != NULL)
550 block_Release (block);
556 * Wait until the FIFO gets below a certain size (if needed).
558 * Note that if more than one thread writes to the FIFO, you cannot assume that
559 * the FIFO is actually below the requested size upon return (since another
560 * thread could have refilled it already). This is typically not an issue, as
561 * this function is meant for (relaxed) congestion control.
563 * This function may be a cancellation point and it is cancel-safe.
565 * @param fifo queue to wait on
566 * @param max_depth wait until the queue has no more than this many blocks
567 * (use SIZE_MAX to ignore this constraint)
568 * @param max_size wait until the queue has no more than this many bytes
569 * (use SIZE_MAX to ignore this constraint)
572 void block_FifoPace (block_fifo_t *fifo, size_t max_depth, size_t max_size)
576 vlc_mutex_lock (&fifo->lock);
577 while ((fifo->i_depth > max_depth) || (fifo->i_size > max_size))
579 mutex_cleanup_push (&fifo->lock);
580 vlc_cond_wait (&fifo->wait_room, &fifo->lock);
583 vlc_mutex_unlock (&fifo->lock);
587 * Immediately queue one block at the end of a FIFO.
589 * @param block head of a block list to queue (may be NULL)
590 * @return total number of bytes appended to the queue
592 size_t block_FifoPut( block_fifo_t *p_fifo, block_t *p_block )
594 size_t i_size = 0, i_depth = 0;
599 for (p_last = p_block; ; p_last = p_last->p_next)
601 i_size += p_last->i_buffer;
607 vlc_mutex_lock (&p_fifo->lock);
608 *p_fifo->pp_last = p_block;
609 p_fifo->pp_last = &p_last->p_next;
610 p_fifo->i_depth += i_depth;
611 p_fifo->i_size += i_size;
612 /* We queued at least one block: wake up one read-waiting thread */
613 vlc_cond_signal( &p_fifo->wait );
614 vlc_mutex_unlock( &p_fifo->lock );
619 void block_FifoWake( block_fifo_t *p_fifo )
621 vlc_mutex_lock( &p_fifo->lock );
622 if( p_fifo->p_first == NULL )
623 p_fifo->b_force_wake = true;
624 vlc_cond_broadcast( &p_fifo->wait );
625 vlc_mutex_unlock( &p_fifo->lock );
629 * Dequeue the first block from the FIFO. If necessary, wait until there is
630 * one block in the queue. This function is (always) cancellation point.
632 * @return a valid block, or NULL if block_FifoWake() was called.
634 block_t *block_FifoGet( block_fifo_t *p_fifo )
640 vlc_mutex_lock( &p_fifo->lock );
641 mutex_cleanup_push( &p_fifo->lock );
643 /* Remember vlc_cond_wait() may cause spurious wakeups
644 * (on both Win32 and POSIX) */
645 while( ( p_fifo->p_first == NULL ) && !p_fifo->b_force_wake )
646 vlc_cond_wait( &p_fifo->wait, &p_fifo->lock );
651 p_fifo->b_force_wake = false;
655 vlc_mutex_unlock( &p_fifo->lock );
659 p_fifo->p_first = b->p_next;
661 p_fifo->i_size -= b->i_buffer;
663 if( p_fifo->p_first == NULL )
665 p_fifo->pp_last = &p_fifo->p_first;
668 /* We don't know how many threads can queue new packets now. */
669 vlc_cond_broadcast( &p_fifo->wait_room );
670 vlc_mutex_unlock( &p_fifo->lock );
677 * Peeks the first block in the FIFO.
678 * If necessary, wait until there is one block.
679 * This function is (always) a cancellation point.
681 * @warning This function leaves the block in the FIFO.
682 * You need to protect against concurrent threads who could dequeue the block.
683 * Preferrably, there should be only one thread reading from the FIFO.
685 * @return a valid block.
687 block_t *block_FifoShow( block_fifo_t *p_fifo )
693 vlc_mutex_lock( &p_fifo->lock );
694 mutex_cleanup_push( &p_fifo->lock );
696 while( p_fifo->p_first == NULL )
697 vlc_cond_wait( &p_fifo->wait, &p_fifo->lock );
705 /* FIXME: not thread-safe */
706 size_t block_FifoSize( const block_fifo_t *p_fifo )
708 return p_fifo->i_size;
711 /* FIXME: not thread-safe */
712 size_t block_FifoCount( const block_fifo_t *p_fifo )
714 return p_fifo->i_depth;