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 = b->i_length = 0;
67 b->pf_release = BlockNoRelease;
71 static void BlockRelease( block_t *p_block )
76 /* Memory alignment */
77 #define BLOCK_ALIGN 16
78 /* Initial size of reserved header and footer */
79 #define BLOCK_PADDING_SIZE 32
80 /* Maximum size of reserved footer before we release with realloc() */
81 #define BLOCK_WASTE_SIZE 2048
83 block_t *block_Alloc( size_t i_size )
85 /* We do only one malloc
86 * TODO: bench if doing 2 malloc but keeping a pool of buffer is better
89 * 2 * BLOCK_PADDING_SIZE -> pre + post padding
91 const size_t i_alloc = i_size + 2 * BLOCK_PADDING_SIZE + BLOCK_ALIGN;
92 block_sys_t *p_sys = malloc( sizeof( *p_sys ) + i_alloc );
97 /* Fill opaque data */
98 p_sys->i_allocated_buffer = i_alloc;
100 block_Init( &p_sys->self, p_sys->p_allocated_buffer + BLOCK_PADDING_SIZE
102 - ((uintptr_t)p_sys->p_allocated_buffer % BLOCK_ALIGN),
104 p_sys->self.pf_release = BlockRelease;
109 block_t *block_Realloc( block_t *p_block, ssize_t i_prebody, size_t i_body )
111 block_sys_t *p_sys = (block_sys_t *)p_block;
112 ssize_t i_buffer_size = i_prebody + i_body;
114 if( i_buffer_size <= 0 )
116 block_Release( p_block );
120 if( p_block->pf_release != BlockRelease )
122 /* Special case when pf_release if overloaded
123 * TODO if used one day, then implement it in a smarter way */
124 block_t *p_dup = block_Duplicate( p_block );
125 block_Release( p_block );
130 p_sys = (block_sys_t *)p_block;
133 /* Adjust reserved header if there is enough room */
134 if( p_block->p_buffer - i_prebody > p_sys->p_allocated_buffer &&
135 p_block->p_buffer - i_prebody < p_sys->p_allocated_buffer +
136 p_sys->i_allocated_buffer )
138 p_block->p_buffer -= i_prebody;
139 p_block->i_buffer += i_prebody;
143 /* Adjust payload size if there is enough room */
144 if( p_block->p_buffer + i_body < p_sys->p_allocated_buffer +
145 p_sys->i_allocated_buffer )
147 p_block->i_buffer = i_buffer_size;
151 /* Not enough room, reallocate the buffer */
152 if( i_body > 0 || i_prebody > 0 )
154 /* FIXME: this is really dumb, we should use realloc() */
155 block_t *p_rea = block_New( NULL, i_buffer_size );
159 p_rea->i_dts = p_block->i_dts;
160 p_rea->i_pts = p_block->i_pts;
161 p_rea->i_flags = p_block->i_flags;
162 p_rea->i_length = p_block->i_length;
163 p_rea->i_rate = p_block->i_rate;
164 p_rea->i_samples = p_block->i_samples;
166 memcpy( p_rea->p_buffer + i_prebody, p_block->p_buffer,
167 __MIN( p_block->i_buffer, p_rea->i_buffer - i_prebody ) );
170 block_Release( p_block );
175 /* We have a very large reserved footer now? Release some of it.
176 * XXX it may not keep the algniment of p_buffer */
177 if( (p_sys->p_allocated_buffer + p_sys->i_allocated_buffer) -
178 (p_block->p_buffer + p_block->i_buffer) > BLOCK_WASTE_SIZE )
180 const ptrdiff_t i_prebody = p_block->p_buffer - p_sys->p_allocated_buffer;
181 const size_t i_new = i_prebody + p_block->i_buffer + 1 * BLOCK_PADDING_SIZE;
182 block_sys_t *p_new = realloc( p_sys, sizeof (*p_sys) + i_new );
187 p_sys->i_allocated_buffer = i_new;
188 p_block = &p_sys->self;
189 p_block->p_buffer = &p_sys->p_allocated_buffer[i_prebody];
196 # include <sys/mman.h>
198 typedef struct block_mmap_t
205 static void block_mmap_Release (block_t *block)
207 block_mmap_t *p_sys = (block_mmap_t *)block;
209 munmap (p_sys->base_addr, p_sys->length);
214 * Creates a block from a virtual address memory mapping (mmap).
215 * This is provided by LibVLC so that mmap blocks can safely be deallocated
216 * even after the allocating plugin has been unloaded from memory.
218 * @param addr base address of the mapping (as returned by mmap)
219 * @param length length (bytes) of the mapping (as passed to mmap)
220 * @return NULL if addr is MAP_FAILED, or an error occurred (in the later
221 * case, munmap(addr, length) is invoked before returning).
223 block_t *block_mmap_Alloc (void *addr, size_t length)
225 if (addr == MAP_FAILED)
228 block_mmap_t *block = malloc (sizeof (*block));
231 munmap (addr, length);
235 block_Init (&block->self, (uint8_t *)addr, length);
236 block->self.pf_release = block_mmap_Release;
237 block->base_addr = addr;
238 block->length = length;
242 block_t *block_mmap_Alloc (void *addr, size_t length)
244 (void)addr; (void)length; return NULL;
251 #define _get_osfhandle(a) ((long) (a))
255 ssize_t pread (int fd, void *buf, size_t count, off_t offset)
257 HANDLE handle = (HANDLE)(intptr_t)_get_osfhandle (fd);
258 if (handle == INVALID_HANDLE_VALUE)
261 OVERLAPPED olap = { .Offset = offset, .OffsetHigh = (offset >> 32), };
263 /* This braindead API will override the file pointer even if we specify
264 * an explicit read offset... So do not expect this to mix well with
265 * regular read() calls. */
266 if (ReadFile (handle, buf, count, &written, &olap))
273 * Loads a file into a block of memory. If possible a private file mapping is
274 * created. Otherwise, the file is read normally. On 32-bits platforms, this
275 * function will not work for very large files, due to memory space
276 * constraints. Cancellation point.
278 * @param fd file descriptor to load from
279 * @return a new block with the file content at p_buffer, and file length at
280 * i_buffer (release it with block_Release()), or NULL upon error (see errno).
282 block_t *block_File (int fd)
287 /* First, get the file size */
291 /* st_size is meaningful for regular files, shared memory and typed memory.
292 * It's also meaning for symlinks, but that's not possible with fstat().
293 * In other cases, it's undefined, and we should really not go further. */
295 # define S_TYPEISSHM( buf ) (0)
297 if (S_ISDIR (st.st_mode))
302 if (!S_ISREG (st.st_mode) && !S_TYPEISSHM (&st))
308 /* Prevent an integer overflow in mmap() and malloc() */
309 if (st.st_size >= SIZE_MAX)
314 length = (size_t)st.st_size;
321 addr = mmap (NULL, length, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
322 if (addr != MAP_FAILED)
323 return block_mmap_Alloc (addr, length);
327 /* If mmap() is not implemented by the OS _or_ the filesystem... */
328 block_t *block = block_Alloc (length);
331 block_cleanup_push (block);
333 for (size_t i = 0; i < length;)
335 ssize_t len = pread (fd, block->p_buffer + i, length - i, i);
338 block_Release (block);
349 * @section Thread-safe block queue functions
353 * Internal state for block queues
357 vlc_mutex_t lock; /* fifo data lock */
358 vlc_cond_t wait; /**< Wait for data */
359 vlc_cond_t wait_room; /**< Wait for queue depth to shrink */
368 block_fifo_t *block_FifoNew( void )
370 block_fifo_t *p_fifo = malloc( sizeof( block_fifo_t ) );
374 vlc_mutex_init( &p_fifo->lock );
375 vlc_cond_init( &p_fifo->wait );
376 vlc_cond_init( &p_fifo->wait_room );
377 p_fifo->p_first = NULL;
378 p_fifo->pp_last = &p_fifo->p_first;
379 p_fifo->i_depth = p_fifo->i_size = 0;
380 p_fifo->b_force_wake = false;
385 void block_FifoRelease( block_fifo_t *p_fifo )
387 block_FifoEmpty( p_fifo );
388 vlc_cond_destroy( &p_fifo->wait_room );
389 vlc_cond_destroy( &p_fifo->wait );
390 vlc_mutex_destroy( &p_fifo->lock );
394 void block_FifoEmpty( block_fifo_t *p_fifo )
398 vlc_mutex_lock( &p_fifo->lock );
399 for( b = p_fifo->p_first; b != NULL; )
408 p_fifo->i_depth = p_fifo->i_size = 0;
409 p_fifo->p_first = NULL;
410 p_fifo->pp_last = &p_fifo->p_first;
411 vlc_cond_broadcast( &p_fifo->wait_room );
412 vlc_mutex_unlock( &p_fifo->lock );
416 * Wait until the FIFO gets below a certain size (if needed).
418 * Note that if more than one thread writes to the FIFO, you cannot assume that
419 * the FIFO is actually below the requested size upon return (since another
420 * thread could have refilled it already). This is typically not an issue, as
421 * this function is meant for (relaxed) congestion control.
423 * This function may be a cancellation point and it is cancel-safe.
425 * @param fifo queue to wait on
426 * @param max_depth wait until the queue has no more than this many blocks
427 * (use SIZE_MAX to ignore this constraint)
428 * @param max_size wait until the queue has no more than this many bytes
429 * (use SIZE_MAX to ignore this constraint)
432 void block_FifoPace (block_fifo_t *fifo, size_t max_depth, size_t max_size)
436 vlc_mutex_lock (&fifo->lock);
437 while ((fifo->i_depth > max_depth) || (fifo->i_size > max_size))
439 mutex_cleanup_push (&fifo->lock);
440 vlc_cond_wait (&fifo->wait_room, &fifo->lock);
443 vlc_mutex_unlock (&fifo->lock);
447 * Immediately queue one block at the end of a FIFO.
449 * @param block head of a block list to queue (may be NULL)
451 size_t block_FifoPut( block_fifo_t *p_fifo, block_t *p_block )
454 vlc_mutex_lock( &p_fifo->lock );
456 while (p_block != NULL)
458 i_size += p_block->i_buffer;
460 *p_fifo->pp_last = p_block;
461 p_fifo->pp_last = &p_block->p_next;
463 p_fifo->i_size += p_block->i_buffer;
465 p_block = p_block->p_next;
468 /* We queued one block: wake up one read-waiting thread */
469 vlc_cond_signal( &p_fifo->wait );
470 vlc_mutex_unlock( &p_fifo->lock );
475 void block_FifoWake( block_fifo_t *p_fifo )
477 vlc_mutex_lock( &p_fifo->lock );
478 if( p_fifo->p_first == NULL )
479 p_fifo->b_force_wake = true;
480 vlc_cond_broadcast( &p_fifo->wait );
481 vlc_mutex_unlock( &p_fifo->lock );
484 block_t *block_FifoGet( block_fifo_t *p_fifo )
490 vlc_mutex_lock( &p_fifo->lock );
491 mutex_cleanup_push( &p_fifo->lock );
493 /* Remember vlc_cond_wait() may cause spurious wakeups
494 * (on both Win32 and POSIX) */
495 while( ( p_fifo->p_first == NULL ) && !p_fifo->b_force_wake )
496 vlc_cond_wait( &p_fifo->wait, &p_fifo->lock );
501 p_fifo->b_force_wake = false;
505 vlc_mutex_unlock( &p_fifo->lock );
509 p_fifo->p_first = b->p_next;
511 p_fifo->i_size -= b->i_buffer;
513 if( p_fifo->p_first == NULL )
515 p_fifo->pp_last = &p_fifo->p_first;
518 /* We don't know how many threads can queue new packets now. */
519 vlc_cond_broadcast( &p_fifo->wait_room );
520 vlc_mutex_unlock( &p_fifo->lock );
526 block_t *block_FifoShow( block_fifo_t *p_fifo )
532 vlc_mutex_lock( &p_fifo->lock );
533 mutex_cleanup_push( &p_fifo->lock );
535 while( p_fifo->p_first == NULL )
536 vlc_cond_wait( &p_fifo->wait, &p_fifo->lock );
544 /* FIXME: not thread-safe */
545 size_t block_FifoSize( const block_fifo_t *p_fifo )
547 return p_fifo->i_size;
550 /* FIXME: not thread-safe */
551 size_t block_FifoCount( const block_fifo_t *p_fifo )
553 return p_fifo->i_depth;