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 */
65 b->i_dts = VLC_TS_INVALID;
72 b->pf_release = BlockNoRelease;
76 static void BlockRelease( block_t *p_block )
81 static void BlockMetaCopy( block_t *restrict out, const block_t *in )
83 out->p_next = in->p_next;
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;
88 out->i_rate = in->i_rate;
89 out->i_samples = in->i_samples;
92 /* Memory alignment */
93 #define BLOCK_ALIGN 16
94 /* Initial size of reserved header and footer */
95 #define BLOCK_PADDING_SIZE 32
96 /* Maximum size of reserved footer before we release with realloc() */
97 #define BLOCK_WASTE_SIZE 2048
99 block_t *block_Alloc( size_t i_size )
101 /* We do only one malloc
102 * TODO: bench if doing 2 malloc but keeping a pool of buffer is better
105 * 2 * BLOCK_PADDING_SIZE -> pre + post padding
107 const size_t i_alloc = i_size + 2 * BLOCK_PADDING_SIZE + BLOCK_ALIGN;
108 block_sys_t *p_sys = malloc( sizeof( *p_sys ) + i_alloc );
113 /* Fill opaque data */
114 p_sys->i_allocated_buffer = i_alloc;
116 block_Init( &p_sys->self, p_sys->p_allocated_buffer + BLOCK_PADDING_SIZE
118 - ((uintptr_t)p_sys->p_allocated_buffer % BLOCK_ALIGN),
120 p_sys->self.pf_release = BlockRelease;
125 block_t *block_Realloc( block_t *p_block, ssize_t i_prebody, size_t i_body )
127 block_sys_t *p_sys = (block_sys_t *)p_block;
128 size_t requested = i_prebody + i_body;
130 /* Corner case: empty block requested */
131 if( i_prebody <= 0 && i_body <= (size_t)(-i_prebody) )
133 block_Release( p_block );
137 if( p_block->pf_release != BlockRelease )
139 /* Special case when pf_release if overloaded
140 * TODO if used one day, then implement it in a smarter way */
141 block_t *p_dup = block_Duplicate( p_block );
142 block_Release( p_block );
147 p_sys = (block_sys_t *)p_block;
150 uint8_t *p_start = p_sys->p_allocated_buffer;
151 uint8_t *p_end = p_sys->p_allocated_buffer + p_sys->i_allocated_buffer;
153 assert( p_block->p_buffer + p_block->i_buffer <= p_end );
154 assert( p_block->p_buffer >= p_start );
156 /* Corner case: the current payload is discarded completely */
157 if( i_prebody <= 0 && p_block->i_buffer <= (size_t)-i_prebody )
158 p_block->i_buffer = 0; /* discard current payload */
159 if( p_block->i_buffer == 0 )
161 size_t available = p_end - p_start;
163 if( requested <= available )
164 { /* Enough room: recycle buffer */
165 size_t extra = available - requested;
167 p_block->p_buffer = p_start + (extra / 2);
168 p_block->i_buffer = requested;
171 /* Not enough room: allocate a new buffer */
172 block_t *p_rea = block_Alloc( requested );
174 BlockMetaCopy( p_rea, p_block );
175 block_Release( p_block );
179 /* First, shrink payload */
181 /* Pull payload start */
184 assert( p_block->i_buffer >= (size_t)-i_prebody );
185 p_block->p_buffer -= i_prebody;
186 p_block->i_buffer += i_prebody;
191 /* Trim payload end */
192 if( p_block->i_buffer > i_body )
193 p_block->i_buffer = i_body;
195 /* Second, reallocate the buffer if we lack space. This is done now to
196 * minimize the payload size for memory copy. */
197 assert( i_prebody >= 0 );
198 if( (size_t)(p_block->p_buffer - p_start) < (size_t)i_prebody
199 || (size_t)(p_end - p_block->p_buffer) < i_body )
201 /* FIXME: this is really dumb, we should use realloc() */
202 block_t *p_rea = block_Alloc( requested );
205 BlockMetaCopy( p_rea, p_block );
206 p_rea->p_buffer += i_prebody;
207 p_rea->i_buffer -= i_prebody;
208 memcpy( p_rea->p_buffer, p_block->p_buffer, p_block->i_buffer );
210 block_Release( p_block );
214 /* We have a very large reserved footer now? Release some of it.
215 * XXX it might not preserve the alignment of p_buffer */
216 if( p_end - (p_block->p_buffer + i_body) > BLOCK_WASTE_SIZE )
218 const ptrdiff_t i_prebody = p_block->p_buffer - p_start;
219 const size_t i_new = requested + 1 * BLOCK_PADDING_SIZE;
220 block_sys_t *p_new = realloc( p_sys, sizeof (*p_sys) + i_new );
225 p_sys->i_allocated_buffer = i_new;
226 p_block = &p_sys->self;
227 p_block->p_buffer = &p_sys->p_allocated_buffer[i_prebody];
231 /* NOTE: p_start and p_end are corrupted from this point */
233 /* Third, expand payload */
235 /* Push payload start */
238 p_block->p_buffer -= i_prebody;
239 p_block->i_buffer += i_prebody;
244 /* Expand payload to requested size */
245 p_block->i_buffer = i_body;
257 static void block_heap_Release (block_t *self)
259 block_heap_t *block = (block_heap_t *)self;
266 * Creates a block from a heap allocation.
267 * This is provided by LibVLC so that manually heap-allocated blocks can safely
268 * be deallocated even after the origin plugin has been unloaded from memory.
270 * When block_Release() is called, VLC will free() the specified pointer.
272 * @param ptr base address of the heap allocation (will be free()'d)
273 * @param addr base address of the useful buffer data
274 * @param length bytes length of the useful buffer datan
275 * @return NULL in case of error (ptr free()'d in that case), or a valid
278 block_t *block_heap_Alloc (void *ptr, void *addr, size_t length)
280 block_heap_t *block = malloc (sizeof (*block));
287 block_Init (&block->self, (uint8_t *)addr, length);
288 block->self.pf_release = block_heap_Release;
294 # include <sys/mman.h>
296 typedef struct block_mmap_t
303 static void block_mmap_Release (block_t *block)
305 block_mmap_t *p_sys = (block_mmap_t *)block;
307 munmap (p_sys->base_addr, p_sys->length);
312 * Creates a block from a virtual address memory mapping (mmap).
313 * This is provided by LibVLC so that mmap blocks can safely be deallocated
314 * even after the allocating plugin has been unloaded from memory.
316 * @param addr base address of the mapping (as returned by mmap)
317 * @param length length (bytes) of the mapping (as passed to mmap)
318 * @return NULL if addr is MAP_FAILED, or an error occurred (in the later
319 * case, munmap(addr, length) is invoked before returning).
321 block_t *block_mmap_Alloc (void *addr, size_t length)
323 if (addr == MAP_FAILED)
326 block_mmap_t *block = malloc (sizeof (*block));
329 munmap (addr, length);
333 block_Init (&block->self, (uint8_t *)addr, length);
334 block->self.pf_release = block_mmap_Release;
335 block->base_addr = addr;
336 block->length = length;
340 block_t *block_mmap_Alloc (void *addr, size_t length)
342 (void)addr; (void)length; return NULL;
349 #define _get_osfhandle(a) ((long) (a))
353 ssize_t pread (int fd, void *buf, size_t count, off_t offset)
355 HANDLE handle = (HANDLE)(intptr_t)_get_osfhandle (fd);
356 if (handle == INVALID_HANDLE_VALUE)
359 OVERLAPPED olap; olap.Offset = offset; olap.OffsetHigh = (offset >> 32);
361 /* This braindead API will override the file pointer even if we specify
362 * an explicit read offset... So do not expect this to mix well with
363 * regular read() calls. */
364 if (ReadFile (handle, buf, count, &written, &olap))
371 * Loads a file into a block of memory. If possible a private file mapping is
372 * created. Otherwise, the file is read normally. On 32-bits platforms, this
373 * function will not work for very large files, due to memory space
374 * constraints. Cancellation point.
376 * @param fd file descriptor to load from
377 * @return a new block with the file content at p_buffer, and file length at
378 * i_buffer (release it with block_Release()), or NULL upon error (see errno).
380 block_t *block_File (int fd)
385 /* First, get the file size */
389 /* st_size is meaningful for regular files, shared memory and typed memory.
390 * It's also meaning for symlinks, but that's not possible with fstat().
391 * In other cases, it's undefined, and we should really not go further. */
393 # define S_TYPEISSHM( buf ) (0)
395 if (S_ISDIR (st.st_mode))
400 if (!S_ISREG (st.st_mode) && !S_TYPEISSHM (&st))
406 /* Prevent an integer overflow in mmap() and malloc() */
407 if (st.st_size >= SIZE_MAX)
412 length = (size_t)st.st_size;
419 addr = mmap (NULL, length, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
420 if (addr != MAP_FAILED)
421 return block_mmap_Alloc (addr, length);
425 /* If mmap() is not implemented by the OS _or_ the filesystem... */
426 block_t *block = block_Alloc (length);
429 block_cleanup_push (block);
431 for (size_t i = 0; i < length;)
433 ssize_t len = pread (fd, block->p_buffer + i, length - i, i);
436 block_Release (block);
447 * @section Thread-safe block queue functions
451 * Internal state for block queues
455 vlc_mutex_t lock; /* fifo data lock */
456 vlc_cond_t wait; /**< Wait for data */
457 vlc_cond_t wait_room; /**< Wait for queue depth to shrink */
466 block_fifo_t *block_FifoNew( void )
468 block_fifo_t *p_fifo = malloc( sizeof( block_fifo_t ) );
472 vlc_mutex_init( &p_fifo->lock );
473 vlc_cond_init( &p_fifo->wait );
474 vlc_cond_init( &p_fifo->wait_room );
475 p_fifo->p_first = NULL;
476 p_fifo->pp_last = &p_fifo->p_first;
477 p_fifo->i_depth = p_fifo->i_size = 0;
478 p_fifo->b_force_wake = false;
483 void block_FifoRelease( block_fifo_t *p_fifo )
485 block_FifoEmpty( p_fifo );
486 vlc_cond_destroy( &p_fifo->wait_room );
487 vlc_cond_destroy( &p_fifo->wait );
488 vlc_mutex_destroy( &p_fifo->lock );
492 void block_FifoEmpty( block_fifo_t *p_fifo )
496 vlc_mutex_lock( &p_fifo->lock );
497 for( b = p_fifo->p_first; b != NULL; )
506 p_fifo->i_depth = p_fifo->i_size = 0;
507 p_fifo->p_first = NULL;
508 p_fifo->pp_last = &p_fifo->p_first;
509 vlc_cond_broadcast( &p_fifo->wait_room );
510 vlc_mutex_unlock( &p_fifo->lock );
514 * Wait until the FIFO gets below a certain size (if needed).
516 * Note that if more than one thread writes to the FIFO, you cannot assume that
517 * the FIFO is actually below the requested size upon return (since another
518 * thread could have refilled it already). This is typically not an issue, as
519 * this function is meant for (relaxed) congestion control.
521 * This function may be a cancellation point and it is cancel-safe.
523 * @param fifo queue to wait on
524 * @param max_depth wait until the queue has no more than this many blocks
525 * (use SIZE_MAX to ignore this constraint)
526 * @param max_size wait until the queue has no more than this many bytes
527 * (use SIZE_MAX to ignore this constraint)
530 void block_FifoPace (block_fifo_t *fifo, size_t max_depth, size_t max_size)
534 vlc_mutex_lock (&fifo->lock);
535 while ((fifo->i_depth > max_depth) || (fifo->i_size > max_size))
537 mutex_cleanup_push (&fifo->lock);
538 vlc_cond_wait (&fifo->wait_room, &fifo->lock);
541 vlc_mutex_unlock (&fifo->lock);
545 * Immediately queue one block at the end of a FIFO.
547 * @param block head of a block list to queue (may be NULL)
549 size_t block_FifoPut( block_fifo_t *p_fifo, block_t *p_block )
552 vlc_mutex_lock( &p_fifo->lock );
554 while (p_block != NULL)
556 i_size += p_block->i_buffer;
558 *p_fifo->pp_last = p_block;
559 p_fifo->pp_last = &p_block->p_next;
561 p_fifo->i_size += p_block->i_buffer;
563 p_block = p_block->p_next;
566 /* We queued one block: wake up one read-waiting thread */
567 vlc_cond_signal( &p_fifo->wait );
568 vlc_mutex_unlock( &p_fifo->lock );
573 void block_FifoWake( block_fifo_t *p_fifo )
575 vlc_mutex_lock( &p_fifo->lock );
576 if( p_fifo->p_first == NULL )
577 p_fifo->b_force_wake = true;
578 vlc_cond_broadcast( &p_fifo->wait );
579 vlc_mutex_unlock( &p_fifo->lock );
582 block_t *block_FifoGet( block_fifo_t *p_fifo )
588 vlc_mutex_lock( &p_fifo->lock );
589 mutex_cleanup_push( &p_fifo->lock );
591 /* Remember vlc_cond_wait() may cause spurious wakeups
592 * (on both Win32 and POSIX) */
593 while( ( p_fifo->p_first == NULL ) && !p_fifo->b_force_wake )
594 vlc_cond_wait( &p_fifo->wait, &p_fifo->lock );
599 p_fifo->b_force_wake = false;
603 vlc_mutex_unlock( &p_fifo->lock );
607 p_fifo->p_first = b->p_next;
609 p_fifo->i_size -= b->i_buffer;
611 if( p_fifo->p_first == NULL )
613 p_fifo->pp_last = &p_fifo->p_first;
616 /* We don't know how many threads can queue new packets now. */
617 vlc_cond_broadcast( &p_fifo->wait_room );
618 vlc_mutex_unlock( &p_fifo->lock );
624 block_t *block_FifoShow( block_fifo_t *p_fifo )
630 vlc_mutex_lock( &p_fifo->lock );
631 mutex_cleanup_push( &p_fifo->lock );
633 while( p_fifo->p_first == NULL )
634 vlc_cond_wait( &p_fifo->wait, &p_fifo->lock );
642 /* FIXME: not thread-safe */
643 size_t block_FifoSize( const block_fifo_t *p_fifo )
645 return p_fifo->i_size;
648 /* FIXME: not thread-safe */
649 size_t block_FifoCount( const block_fifo_t *p_fifo )
651 return p_fifo->i_depth;