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;
70 b->pf_release = BlockNoRelease;
74 static void BlockRelease( block_t *p_block )
79 static void BlockMetaCopy( block_t *restrict out, const block_t *in )
81 out->i_dts = in->i_dts;
82 out->i_pts = in->i_pts;
83 out->i_flags = in->i_flags;
84 out->i_length = in->i_length;
85 out->i_rate = in->i_rate;
86 out->i_samples = in->i_samples;
89 /* Memory alignment */
90 #define BLOCK_ALIGN 16
91 /* Initial size of reserved header and footer */
92 #define BLOCK_PADDING_SIZE 32
93 /* Maximum size of reserved footer before we release with realloc() */
94 #define BLOCK_WASTE_SIZE 2048
96 block_t *block_Alloc( size_t i_size )
98 /* We do only one malloc
99 * TODO: bench if doing 2 malloc but keeping a pool of buffer is better
102 * 2 * BLOCK_PADDING_SIZE -> pre + post padding
104 const size_t i_alloc = i_size + 2 * BLOCK_PADDING_SIZE + BLOCK_ALIGN;
105 block_sys_t *p_sys = malloc( sizeof( *p_sys ) + i_alloc );
110 /* Fill opaque data */
111 p_sys->i_allocated_buffer = i_alloc;
113 block_Init( &p_sys->self, p_sys->p_allocated_buffer + BLOCK_PADDING_SIZE
115 - ((uintptr_t)p_sys->p_allocated_buffer % BLOCK_ALIGN),
117 p_sys->self.pf_release = BlockRelease;
122 block_t *block_Realloc( block_t *p_block, ssize_t i_prebody, size_t i_body )
124 block_sys_t *p_sys = (block_sys_t *)p_block;
125 size_t requested = i_prebody + i_body;
127 /* Corner case: empty block requested */
128 if( i_prebody <= 0 && i_body <= (size_t)(-i_prebody) )
130 block_Release( p_block );
134 if( p_block->pf_release != BlockRelease )
136 /* Special case when pf_release if overloaded
137 * TODO if used one day, then implement it in a smarter way */
138 block_t *p_dup = block_Duplicate( p_block );
139 block_Release( p_block );
144 p_sys = (block_sys_t *)p_block;
147 uint8_t *p_start = p_sys->p_allocated_buffer;
148 uint8_t *p_end = p_sys->p_allocated_buffer + p_sys->i_allocated_buffer;
150 assert( p_block->p_buffer + p_block->i_buffer <= p_end );
151 assert( p_block->p_buffer >= p_start );
153 /* Corner case: the current payload is discarded completely */
154 if( i_prebody <= 0 && p_block->i_buffer <= (size_t)-i_prebody )
155 p_block->i_buffer = 0; /* discard current payload */
156 if( p_block->i_buffer == 0 )
158 size_t available = p_end - p_start;
160 if( requested <= available )
161 { /* Enough room: recycle buffer */
162 size_t extra = available - requested;
164 p_block->p_buffer = p_start + (extra / 2);
165 p_block->i_buffer = requested;
168 /* Not enough room: allocate a new buffer */
169 block_t *p_rea = block_Alloc( requested );
171 BlockMetaCopy( p_rea, p_block );
172 block_Release( p_block );
176 /* First, shrink payload */
178 /* Pull payload start */
181 assert( p_block->i_buffer >= (size_t)-i_prebody );
182 p_block->p_buffer -= i_prebody;
183 p_block->i_buffer += i_prebody;
188 /* Trim payload end */
189 if( p_block->i_buffer > i_body )
190 p_block->i_buffer = i_body;
192 /* Second, reallocate the buffer if we lack space. This is done now to
193 * minimize the payload size for memory copy. */
194 assert( i_prebody >= 0 );
195 if( (size_t)(p_block->p_buffer - p_start) < (size_t)i_prebody
196 || (size_t)(p_end - p_block->p_buffer) < i_body )
198 /* FIXME: this is really dumb, we should use realloc() */
199 block_t *p_rea = block_Alloc( requested );
202 BlockMetaCopy( p_rea, p_block );
203 p_rea->p_buffer += i_prebody;
204 p_rea->i_buffer -= i_prebody;
205 memcpy( p_rea->p_buffer, p_block->p_buffer, p_block->i_buffer );
207 block_Release( p_block );
211 /* We have a very large reserved footer now? Release some of it.
212 * XXX it might not preserve the alignment of p_buffer */
213 if( p_end - (p_block->p_buffer + i_body) > BLOCK_WASTE_SIZE )
215 const ptrdiff_t i_prebody = p_block->p_buffer - p_start;
216 const size_t i_new = requested + 1 * BLOCK_PADDING_SIZE;
217 block_sys_t *p_new = realloc( p_sys, sizeof (*p_sys) + i_new );
222 p_sys->i_allocated_buffer = i_new;
223 p_block = &p_sys->self;
224 p_block->p_buffer = &p_sys->p_allocated_buffer[i_prebody];
228 /* NOTE: p_start and p_end are corrupted from this point */
230 /* Third, expand payload */
232 /* Push payload start */
235 p_block->p_buffer -= i_prebody;
236 p_block->i_buffer += i_prebody;
241 /* Expand payload to requested size */
242 p_block->i_buffer = i_body;
254 static void block_heap_Release (block_t *self)
256 block_heap_t *block = (block_heap_t *)self;
263 * Creates a block from a heap allocation.
264 * This is provided by LibVLC so that manually heap-allocated blocks can safely
265 * be deallocated even after the origin plugin has been unloaded from memory.
267 * When block_Release() is called, VLC will free() the specified pointer.
269 * @param ptr base address of the heap allocation (will be free()'d)
270 * @param addr base address of the useful buffer data
271 * @param length bytes length of the useful buffer datan
272 * @return NULL in case of error (ptr free()'d in that case), or a valid
275 block_t *block_heap_Alloc (void *ptr, void *addr, size_t length)
277 block_heap_t *block = malloc (sizeof (*block));
284 block_Init (&block->self, (uint8_t *)addr, length);
285 block->self.pf_release = block_heap_Release;
291 # include <sys/mman.h>
293 typedef struct block_mmap_t
300 static void block_mmap_Release (block_t *block)
302 block_mmap_t *p_sys = (block_mmap_t *)block;
304 munmap (p_sys->base_addr, p_sys->length);
309 * Creates a block from a virtual address memory mapping (mmap).
310 * This is provided by LibVLC so that mmap blocks can safely be deallocated
311 * even after the allocating plugin has been unloaded from memory.
313 * @param addr base address of the mapping (as returned by mmap)
314 * @param length length (bytes) of the mapping (as passed to mmap)
315 * @return NULL if addr is MAP_FAILED, or an error occurred (in the later
316 * case, munmap(addr, length) is invoked before returning).
318 block_t *block_mmap_Alloc (void *addr, size_t length)
320 if (addr == MAP_FAILED)
323 block_mmap_t *block = malloc (sizeof (*block));
326 munmap (addr, length);
330 block_Init (&block->self, (uint8_t *)addr, length);
331 block->self.pf_release = block_mmap_Release;
332 block->base_addr = addr;
333 block->length = length;
337 block_t *block_mmap_Alloc (void *addr, size_t length)
339 (void)addr; (void)length; return NULL;
346 #define _get_osfhandle(a) ((long) (a))
350 ssize_t pread (int fd, void *buf, size_t count, off_t offset)
352 HANDLE handle = (HANDLE)(intptr_t)_get_osfhandle (fd);
353 if (handle == INVALID_HANDLE_VALUE)
356 OVERLAPPED olap; olap.Offset = offset; olap.OffsetHigh = (offset >> 32);
358 /* This braindead API will override the file pointer even if we specify
359 * an explicit read offset... So do not expect this to mix well with
360 * regular read() calls. */
361 if (ReadFile (handle, buf, count, &written, &olap))
368 * Loads a file into a block of memory. If possible a private file mapping is
369 * created. Otherwise, the file is read normally. On 32-bits platforms, this
370 * function will not work for very large files, due to memory space
371 * constraints. Cancellation point.
373 * @param fd file descriptor to load from
374 * @return a new block with the file content at p_buffer, and file length at
375 * i_buffer (release it with block_Release()), or NULL upon error (see errno).
377 block_t *block_File (int fd)
382 /* First, get the file size */
386 /* st_size is meaningful for regular files, shared memory and typed memory.
387 * It's also meaning for symlinks, but that's not possible with fstat().
388 * In other cases, it's undefined, and we should really not go further. */
390 # define S_TYPEISSHM( buf ) (0)
392 if (S_ISDIR (st.st_mode))
397 if (!S_ISREG (st.st_mode) && !S_TYPEISSHM (&st))
403 /* Prevent an integer overflow in mmap() and malloc() */
404 if (st.st_size >= SIZE_MAX)
409 length = (size_t)st.st_size;
416 addr = mmap (NULL, length, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
417 if (addr != MAP_FAILED)
418 return block_mmap_Alloc (addr, length);
422 /* If mmap() is not implemented by the OS _or_ the filesystem... */
423 block_t *block = block_Alloc (length);
426 block_cleanup_push (block);
428 for (size_t i = 0; i < length;)
430 ssize_t len = pread (fd, block->p_buffer + i, length - i, i);
433 block_Release (block);
444 * @section Thread-safe block queue functions
448 * Internal state for block queues
452 vlc_mutex_t lock; /* fifo data lock */
453 vlc_cond_t wait; /**< Wait for data */
454 vlc_cond_t wait_room; /**< Wait for queue depth to shrink */
463 block_fifo_t *block_FifoNew( void )
465 block_fifo_t *p_fifo = malloc( sizeof( block_fifo_t ) );
469 vlc_mutex_init( &p_fifo->lock );
470 vlc_cond_init( &p_fifo->wait );
471 vlc_cond_init( &p_fifo->wait_room );
472 p_fifo->p_first = NULL;
473 p_fifo->pp_last = &p_fifo->p_first;
474 p_fifo->i_depth = p_fifo->i_size = 0;
475 p_fifo->b_force_wake = false;
480 void block_FifoRelease( block_fifo_t *p_fifo )
482 block_FifoEmpty( p_fifo );
483 vlc_cond_destroy( &p_fifo->wait_room );
484 vlc_cond_destroy( &p_fifo->wait );
485 vlc_mutex_destroy( &p_fifo->lock );
489 void block_FifoEmpty( block_fifo_t *p_fifo )
493 vlc_mutex_lock( &p_fifo->lock );
494 for( b = p_fifo->p_first; b != NULL; )
503 p_fifo->i_depth = p_fifo->i_size = 0;
504 p_fifo->p_first = NULL;
505 p_fifo->pp_last = &p_fifo->p_first;
506 vlc_cond_broadcast( &p_fifo->wait_room );
507 vlc_mutex_unlock( &p_fifo->lock );
511 * Wait until the FIFO gets below a certain size (if needed).
513 * Note that if more than one thread writes to the FIFO, you cannot assume that
514 * the FIFO is actually below the requested size upon return (since another
515 * thread could have refilled it already). This is typically not an issue, as
516 * this function is meant for (relaxed) congestion control.
518 * This function may be a cancellation point and it is cancel-safe.
520 * @param fifo queue to wait on
521 * @param max_depth wait until the queue has no more than this many blocks
522 * (use SIZE_MAX to ignore this constraint)
523 * @param max_size wait until the queue has no more than this many bytes
524 * (use SIZE_MAX to ignore this constraint)
527 void block_FifoPace (block_fifo_t *fifo, size_t max_depth, size_t max_size)
531 vlc_mutex_lock (&fifo->lock);
532 while ((fifo->i_depth > max_depth) || (fifo->i_size > max_size))
534 mutex_cleanup_push (&fifo->lock);
535 vlc_cond_wait (&fifo->wait_room, &fifo->lock);
538 vlc_mutex_unlock (&fifo->lock);
542 * Immediately queue one block at the end of a FIFO.
544 * @param block head of a block list to queue (may be NULL)
546 size_t block_FifoPut( block_fifo_t *p_fifo, block_t *p_block )
549 vlc_mutex_lock( &p_fifo->lock );
551 while (p_block != NULL)
553 i_size += p_block->i_buffer;
555 *p_fifo->pp_last = p_block;
556 p_fifo->pp_last = &p_block->p_next;
558 p_fifo->i_size += p_block->i_buffer;
560 p_block = p_block->p_next;
563 /* We queued one block: wake up one read-waiting thread */
564 vlc_cond_signal( &p_fifo->wait );
565 vlc_mutex_unlock( &p_fifo->lock );
570 void block_FifoWake( block_fifo_t *p_fifo )
572 vlc_mutex_lock( &p_fifo->lock );
573 if( p_fifo->p_first == NULL )
574 p_fifo->b_force_wake = true;
575 vlc_cond_broadcast( &p_fifo->wait );
576 vlc_mutex_unlock( &p_fifo->lock );
579 block_t *block_FifoGet( block_fifo_t *p_fifo )
585 vlc_mutex_lock( &p_fifo->lock );
586 mutex_cleanup_push( &p_fifo->lock );
588 /* Remember vlc_cond_wait() may cause spurious wakeups
589 * (on both Win32 and POSIX) */
590 while( ( p_fifo->p_first == NULL ) && !p_fifo->b_force_wake )
591 vlc_cond_wait( &p_fifo->wait, &p_fifo->lock );
596 p_fifo->b_force_wake = false;
600 vlc_mutex_unlock( &p_fifo->lock );
604 p_fifo->p_first = b->p_next;
606 p_fifo->i_size -= b->i_buffer;
608 if( p_fifo->p_first == NULL )
610 p_fifo->pp_last = &p_fifo->p_first;
613 /* We don't know how many threads can queue new packets now. */
614 vlc_cond_broadcast( &p_fifo->wait_room );
615 vlc_mutex_unlock( &p_fifo->lock );
621 block_t *block_FifoShow( block_fifo_t *p_fifo )
627 vlc_mutex_lock( &p_fifo->lock );
628 mutex_cleanup_push( &p_fifo->lock );
630 while( p_fifo->p_first == NULL )
631 vlc_cond_wait( &p_fifo->wait, &p_fifo->lock );
639 /* FIXME: not thread-safe */
640 size_t block_FifoSize( const block_fifo_t *p_fifo )
642 return p_fifo->i_size;
645 /* FIXME: not thread-safe */
646 size_t block_FifoCount( const block_fifo_t *p_fifo )
648 return p_fifo->i_depth;