1 /*****************************************************************************
2 * block.c: Data blocks management functions
3 *****************************************************************************
4 * Copyright (C) 2003-2004 the VideoLAN team
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>
33 #include "vlc_block.h"
36 * @section Block handling functions.
40 * Internal state for heap block.
45 size_t i_allocated_buffer;
46 uint8_t p_allocated_buffer[];
50 static void BlockNoRelease( block_t *b )
52 fprintf( stderr, "block %p has no release callback! This is a bug!\n", b );
57 void block_Init( block_t *restrict b, void *buf, size_t size )
59 /* Fill all fields to their default */
62 b->i_pts = b->i_dts = BLOCK_TS_INVALID;
68 b->pf_release = BlockNoRelease;
72 static void BlockRelease( block_t *p_block )
77 /* Memory alignment */
78 #define BLOCK_ALIGN 16
79 /* Initial size of reserved header and footer */
80 #define BLOCK_PADDING_SIZE 32
81 /* Maximum size of reserved footer before we release with realloc() */
82 #define BLOCK_WASTE_SIZE 2048
84 block_t *block_Alloc( size_t i_size )
86 /* We do only one malloc
87 * TODO: bench if doing 2 malloc but keeping a pool of buffer is better
90 * 2 * BLOCK_PADDING_SIZE -> pre + post padding
92 const size_t i_alloc = i_size + 2 * BLOCK_PADDING_SIZE + BLOCK_ALIGN;
93 block_sys_t *p_sys = malloc( sizeof( *p_sys ) + i_alloc );
98 /* Fill opaque data */
99 p_sys->i_allocated_buffer = i_alloc;
101 block_Init( &p_sys->self, p_sys->p_allocated_buffer + BLOCK_PADDING_SIZE
103 - ((uintptr_t)p_sys->p_allocated_buffer % BLOCK_ALIGN),
105 p_sys->self.pf_release = BlockRelease;
110 block_t *block_Realloc( block_t *p_block, ssize_t i_prebody, size_t i_body )
112 block_sys_t *p_sys = (block_sys_t *)p_block;
113 ssize_t i_buffer_size = i_prebody + i_body;
115 if( i_buffer_size <= 0 )
117 block_Release( p_block );
121 if( p_block->pf_release != BlockRelease )
123 /* Special case when pf_release if overloaded
124 * TODO if used one day, then implement it in a smarter way */
125 block_t *p_dup = block_Duplicate( p_block );
126 block_Release( p_block );
131 p_sys = (block_sys_t *)p_block;
134 /* Adjust reserved header if there is enough room */
135 if( p_block->p_buffer - i_prebody > p_sys->p_allocated_buffer &&
136 p_block->p_buffer - i_prebody < p_sys->p_allocated_buffer +
137 p_sys->i_allocated_buffer )
139 p_block->p_buffer -= i_prebody;
140 p_block->i_buffer += i_prebody;
144 /* Adjust payload size if there is enough room */
145 if( p_block->p_buffer + i_body < p_sys->p_allocated_buffer +
146 p_sys->i_allocated_buffer )
148 p_block->i_buffer = i_buffer_size;
152 /* Not enough room, reallocate the buffer */
153 if( i_body > 0 || i_prebody > 0 )
155 /* FIXME: this is really dumb, we should use realloc() */
156 block_t *p_rea = block_New( NULL, i_buffer_size );
160 p_rea->i_dts = p_block->i_dts;
161 p_rea->i_pts = p_block->i_pts;
162 p_rea->i_flags = p_block->i_flags;
163 p_rea->i_length = p_block->i_length;
164 p_rea->i_rate = p_block->i_rate;
165 p_rea->i_samples = p_block->i_samples;
167 memcpy( p_rea->p_buffer + i_prebody, p_block->p_buffer,
168 __MIN( p_block->i_buffer, p_rea->i_buffer - i_prebody ) );
171 block_Release( p_block );
176 /* We have a very large reserved footer now? Release some of it.
177 * XXX it may not keep the algniment of p_buffer */
178 if( (p_sys->p_allocated_buffer + p_sys->i_allocated_buffer) -
179 (p_block->p_buffer + p_block->i_buffer) > BLOCK_WASTE_SIZE )
181 const ptrdiff_t i_prebody = p_block->p_buffer - p_sys->p_allocated_buffer;
182 const size_t i_new = i_prebody + p_block->i_buffer + 1 * BLOCK_PADDING_SIZE;
183 block_sys_t *p_new = realloc( p_sys, sizeof (*p_sys) + i_new );
188 p_sys->i_allocated_buffer = i_new;
189 p_block = &p_sys->self;
190 p_block->p_buffer = &p_sys->p_allocated_buffer[i_prebody];
197 # include <sys/mman.h>
199 typedef struct block_mmap_t
206 static void block_mmap_Release (block_t *block)
208 block_mmap_t *p_sys = (block_mmap_t *)block;
210 munmap (p_sys->base_addr, p_sys->length);
215 * Creates a block from a virtual address memory mapping (mmap).
216 * This is provided by LibVLC so that mmap blocks can safely be deallocated
217 * even after the allocating plugin has been unloaded from memory.
219 * @param addr base address of the mapping (as returned by mmap)
220 * @param length length (bytes) of the mapping (as passed to mmap)
221 * @return NULL if addr is MAP_FAILED, or an error occurred (in the later
222 * case, munmap(addr, length) is invoked before returning).
224 block_t *block_mmap_Alloc (void *addr, size_t length)
226 if (addr == MAP_FAILED)
229 block_mmap_t *block = malloc (sizeof (*block));
232 munmap (addr, length);
236 block_Init (&block->self, (uint8_t *)addr, length);
237 block->self.pf_release = block_mmap_Release;
238 block->base_addr = addr;
239 block->length = length;
243 block_t *block_mmap_Alloc (void *addr, size_t length)
245 (void)addr; (void)length; return NULL;
252 #define _get_osfhandle(a) ((long) (a))
256 ssize_t pread (int fd, void *buf, size_t count, off_t offset)
258 HANDLE handle = (HANDLE)(intptr_t)_get_osfhandle (fd);
259 if (handle == INVALID_HANDLE_VALUE)
262 OVERLAPPED olap = { .Offset = offset, .OffsetHigh = (offset >> 32), };
264 /* This braindead API will override the file pointer even if we specify
265 * an explicit read offset... So do not expect this to mix well with
266 * regular read() calls. */
267 if (ReadFile (handle, buf, count, &written, &olap))
274 * Loads a file into a block of memory. If possible a private file mapping is
275 * created. Otherwise, the file is read normally. On 32-bits platforms, this
276 * function will not work for very large files, due to memory space
277 * constraints. Cancellation point.
279 * @param fd file descriptor to load from
280 * @return a new block with the file content at p_buffer, and file length at
281 * i_buffer (release it with block_Release()), or NULL upon error (see errno).
283 block_t *block_File (int fd)
288 /* First, get the file size */
292 /* st_size is meaningful for regular files, shared memory and typed memory.
293 * It's also meaning for symlinks, but that's not possible with fstat().
294 * In other cases, it's undefined, and we should really not go further. */
296 # define S_TYPEISSHM( buf ) (0)
298 if (S_ISDIR (st.st_mode))
303 if (!S_ISREG (st.st_mode) && !S_TYPEISSHM (&st))
309 /* Prevent an integer overflow in mmap() and malloc() */
310 if (st.st_size >= SIZE_MAX)
315 length = (size_t)st.st_size;
322 addr = mmap (NULL, length, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
323 if (addr != MAP_FAILED)
324 return block_mmap_Alloc (addr, length);
328 /* If mmap() is not implemented by the OS _or_ the filesystem... */
329 block_t *block = block_Alloc (length);
332 block_cleanup_push (block);
334 for (size_t i = 0; i < length;)
336 ssize_t len = pread (fd, block->p_buffer + i, length - i, i);
339 block_Release (block);
350 * @section Thread-safe block queue functions
354 * Internal state for block queues
358 vlc_mutex_t lock; /* fifo data lock */
359 vlc_cond_t wait; /**< Wait for data */
360 vlc_cond_t wait_room; /**< Wait for queue depth to shrink */
369 block_fifo_t *block_FifoNew( void )
371 block_fifo_t *p_fifo = malloc( sizeof( block_fifo_t ) );
375 vlc_mutex_init( &p_fifo->lock );
376 vlc_cond_init( &p_fifo->wait );
377 vlc_cond_init( &p_fifo->wait_room );
378 p_fifo->p_first = NULL;
379 p_fifo->pp_last = &p_fifo->p_first;
380 p_fifo->i_depth = p_fifo->i_size = 0;
381 p_fifo->b_force_wake = false;
386 void block_FifoRelease( block_fifo_t *p_fifo )
388 block_FifoEmpty( p_fifo );
389 vlc_cond_destroy( &p_fifo->wait_room );
390 vlc_cond_destroy( &p_fifo->wait );
391 vlc_mutex_destroy( &p_fifo->lock );
395 void block_FifoEmpty( block_fifo_t *p_fifo )
399 vlc_mutex_lock( &p_fifo->lock );
400 for( b = p_fifo->p_first; b != NULL; )
409 p_fifo->i_depth = p_fifo->i_size = 0;
410 p_fifo->p_first = NULL;
411 p_fifo->pp_last = &p_fifo->p_first;
412 vlc_cond_broadcast( &p_fifo->wait_room );
413 vlc_mutex_unlock( &p_fifo->lock );
417 * Wait until the FIFO gets below a certain size (if needed).
419 * Note that if more than one thread writes to the FIFO, you cannot assume that
420 * the FIFO is actually below the requested size upon return (since another
421 * thread could have refilled it already). This is typically not an issue, as
422 * this function is meant for (relaxed) congestion control.
424 * This function may be a cancellation point and it is cancel-safe.
426 * @param fifo queue to wait on
427 * @param max_depth wait until the queue has no more than this many blocks
428 * (use SIZE_MAX to ignore this constraint)
429 * @param max_size wait until the queue has no more than this many bytes
430 * (use SIZE_MAX to ignore this constraint)
433 void block_FifoPace (block_fifo_t *fifo, size_t max_depth, size_t max_size)
437 vlc_mutex_lock (&fifo->lock);
438 while ((fifo->i_depth > max_depth) || (fifo->i_size > max_size))
440 mutex_cleanup_push (&fifo->lock);
441 vlc_cond_wait (&fifo->wait_room, &fifo->lock);
444 vlc_mutex_unlock (&fifo->lock);
448 * Immediately queue one block at the end of a FIFO.
450 * @param block head of a block list to queue (may be NULL)
452 size_t block_FifoPut( block_fifo_t *p_fifo, block_t *p_block )
455 vlc_mutex_lock( &p_fifo->lock );
457 while (p_block != NULL)
459 i_size += p_block->i_buffer;
461 *p_fifo->pp_last = p_block;
462 p_fifo->pp_last = &p_block->p_next;
464 p_fifo->i_size += p_block->i_buffer;
466 p_block = p_block->p_next;
469 /* We queued one block: wake up one read-waiting thread */
470 vlc_cond_signal( &p_fifo->wait );
471 vlc_mutex_unlock( &p_fifo->lock );
476 void block_FifoWake( block_fifo_t *p_fifo )
478 vlc_mutex_lock( &p_fifo->lock );
479 if( p_fifo->p_first == NULL )
480 p_fifo->b_force_wake = true;
481 vlc_cond_broadcast( &p_fifo->wait );
482 vlc_mutex_unlock( &p_fifo->lock );
485 block_t *block_FifoGet( block_fifo_t *p_fifo )
491 vlc_mutex_lock( &p_fifo->lock );
492 mutex_cleanup_push( &p_fifo->lock );
494 /* Remember vlc_cond_wait() may cause spurious wakeups
495 * (on both Win32 and POSIX) */
496 while( ( p_fifo->p_first == NULL ) && !p_fifo->b_force_wake )
497 vlc_cond_wait( &p_fifo->wait, &p_fifo->lock );
502 p_fifo->b_force_wake = false;
506 vlc_mutex_unlock( &p_fifo->lock );
510 p_fifo->p_first = b->p_next;
512 p_fifo->i_size -= b->i_buffer;
514 if( p_fifo->p_first == NULL )
516 p_fifo->pp_last = &p_fifo->p_first;
519 /* We don't know how many threads can queue new packets now. */
520 vlc_cond_broadcast( &p_fifo->wait_room );
521 vlc_mutex_unlock( &p_fifo->lock );
527 block_t *block_FifoShow( block_fifo_t *p_fifo )
533 vlc_mutex_lock( &p_fifo->lock );
534 mutex_cleanup_push( &p_fifo->lock );
536 while( p_fifo->p_first == NULL )
537 vlc_cond_wait( &p_fifo->wait, &p_fifo->lock );
545 /* FIXME: not thread-safe */
546 size_t block_FifoSize( const block_fifo_t *p_fifo )
548 return p_fifo->i_size;
551 /* FIXME: not thread-safe */
552 size_t block_FifoCount( const block_fifo_t *p_fifo )
554 return p_fifo->i_depth;