* block.c: Data blocks management functions
*****************************************************************************
* Copyright (C) 2003-2004 the VideoLAN team
- * $Id$
+ * Copyright (C) 2007-2009 Rémi Denis-Courmont
*
* Authors: Laurent Aimar <fenrir@videolan.org>
*
#include <vlc_common.h>
#include <sys/stat.h>
+#include <assert.h>
+#include <errno.h>
#include "vlc_block.h"
-/*****************************************************************************
- * Block functions.
- *****************************************************************************/
-/* private */
+/**
+ * @section Block handling functions.
+ */
+
+/**
+ * Internal state for heap block.
+ */
struct block_sys_t
{
block_t self;
size_t i_allocated_buffer;
- uint8_t p_allocated_buffer[0];
+ uint8_t p_allocated_buffer[];
};
#ifndef NDEBUG
void block_Init( block_t *restrict b, void *buf, size_t size )
{
/* Fill all fields to their default */
- b->p_next = b->p_prev = NULL;
+ b->p_next = NULL;
b->i_flags = 0;
- b->i_pts = b->i_dts = b->i_length = 0;
+ b->i_pts =
+ b->i_dts = VLC_TS_INVALID;
+ b->i_length = 0;
b->i_rate = 0;
+ b->i_nb_samples = 0;
b->p_buffer = buf;
b->i_buffer = size;
#ifndef NDEBUG
free( p_block );
}
-/* Memory alignment */
+static void BlockMetaCopy( block_t *restrict out, const block_t *in )
+{
+ out->p_next = in->p_next;
+ out->i_dts = in->i_dts;
+ out->i_pts = in->i_pts;
+ out->i_flags = in->i_flags;
+ out->i_length = in->i_length;
+ out->i_rate = in->i_rate;
+ out->i_nb_samples = in->i_nb_samples;
+}
+
+/* Memory alignment (must be a multiple of sizeof(void*) and a power of two) */
#define BLOCK_ALIGN 16
-/* Initial size of reserved header and footer */
-#define BLOCK_PADDING_SIZE 32
+/* Initial reserved header and footer size (must be multiple of alignment) */
+#define BLOCK_PADDING 32
/* Maximum size of reserved footer before we release with realloc() */
#define BLOCK_WASTE_SIZE 2048
{
/* We do only one malloc
* TODO: bench if doing 2 malloc but keeping a pool of buffer is better
- * TODO: use memalign
- * 16 -> align on 16
- * 2 * BLOCK_PADDING_SIZE -> pre + post padding
+ * 2 * BLOCK_PADDING -> pre + post padding
*/
- const size_t i_alloc = i_size + 2 * BLOCK_PADDING_SIZE + BLOCK_ALIGN;
- block_sys_t *p_sys = malloc( sizeof( *p_sys ) + i_alloc );
+ block_sys_t *p_sys;
+ uint8_t *buf;
+
+#define ALIGN(x) (((x) + BLOCK_ALIGN - 1) & ~(BLOCK_ALIGN - 1))
+#if 0 /*def HAVE_POSIX_MEMALIGN */
+ /* posix_memalign(,16,) is much slower than malloc() on glibc.
+ * -- Courmisch, September 2009, glibc 2.5 & 2.9 */
+ const size_t i_alloc = ALIGN(sizeof(*p_sys)) + (2 * BLOCK_PADDING)
+ + ALIGN(i_size);
+ void *ptr;
+
+ if( posix_memalign( &ptr, BLOCK_ALIGN, i_alloc ) )
+ return NULL;
+
+ p_sys = ptr;
+ buf = p_sys->p_allocated_buffer + (-sizeof(*p_sys) & (BLOCK_ALIGN - 1));
+#else
+ const size_t i_alloc = sizeof(*p_sys) + BLOCK_ALIGN + (2 * BLOCK_PADDING)
+ + ALIGN(i_size);
+ p_sys = malloc( i_alloc );
if( p_sys == NULL )
return NULL;
- /* Fill opaque data */
- p_sys->i_allocated_buffer = i_alloc;
+ buf = (void *)ALIGN((uintptr_t)p_sys->p_allocated_buffer);
+
+#endif
+ buf += BLOCK_PADDING;
- block_Init( &p_sys->self, p_sys->p_allocated_buffer + BLOCK_PADDING_SIZE
- + BLOCK_ALIGN
- - ((uintptr_t)p_sys->p_allocated_buffer % BLOCK_ALIGN),
- i_size );
+ block_Init( &p_sys->self, buf, i_size );
p_sys->self.pf_release = BlockRelease;
+ /* Fill opaque data */
+ p_sys->i_allocated_buffer = i_alloc - sizeof(*p_sys);
return &p_sys->self;
}
block_t *block_Realloc( block_t *p_block, ssize_t i_prebody, size_t i_body )
{
block_sys_t *p_sys = (block_sys_t *)p_block;
- ssize_t i_buffer_size = i_prebody + i_body;
+ size_t requested = i_prebody + i_body;
- if( i_buffer_size <= 0 )
+ /* Corner case: empty block requested */
+ if( i_prebody <= 0 && i_body <= (size_t)(-i_prebody) )
{
block_Release( p_block );
return NULL;
return NULL;
p_block = p_dup;
+ p_sys = (block_sys_t *)p_block;
}
- /* Adjust reserved header if there is enough room */
- if( p_block->p_buffer - i_prebody > p_sys->p_allocated_buffer &&
- p_block->p_buffer - i_prebody < p_sys->p_allocated_buffer +
- p_sys->i_allocated_buffer )
+ uint8_t *p_start = p_sys->p_allocated_buffer;
+ uint8_t *p_end = p_sys->p_allocated_buffer + p_sys->i_allocated_buffer;
+
+ assert( p_block->p_buffer + p_block->i_buffer <= p_end );
+ assert( p_block->p_buffer >= p_start );
+
+ /* Corner case: the current payload is discarded completely */
+ if( i_prebody <= 0 && p_block->i_buffer <= (size_t)-i_prebody )
+ p_block->i_buffer = 0; /* discard current payload */
+ if( p_block->i_buffer == 0 )
{
+ size_t available = p_end - p_start;
+
+ if( requested <= available )
+ { /* Enough room: recycle buffer */
+ size_t extra = available - requested;
+
+ p_block->p_buffer = p_start + (extra / 2);
+ p_block->i_buffer = requested;
+ return p_block;
+ }
+ /* Not enough room: allocate a new buffer */
+ block_t *p_rea = block_Alloc( requested );
+ if( p_rea )
+ BlockMetaCopy( p_rea, p_block );
+ block_Release( p_block );
+ return p_rea;
+ }
+
+ /* First, shrink payload */
+
+ /* Pull payload start */
+ if( i_prebody < 0 )
+ {
+ assert( p_block->i_buffer >= (size_t)-i_prebody );
p_block->p_buffer -= i_prebody;
p_block->i_buffer += i_prebody;
+ i_body += i_prebody;
i_prebody = 0;
}
- /* Adjust payload size if there is enough room */
- if( p_block->p_buffer + i_body < p_sys->p_allocated_buffer +
- p_sys->i_allocated_buffer )
- {
- p_block->i_buffer = i_buffer_size;
- i_body = 0;
- }
+ /* Trim payload end */
+ if( p_block->i_buffer > i_body )
+ p_block->i_buffer = i_body;
- /* Not enough room, reallocate the buffer */
- if( i_body > 0 || i_prebody > 0 )
+ /* Second, reallocate the buffer if we lack space. This is done now to
+ * minimize the payload size for memory copy. */
+ assert( i_prebody >= 0 );
+ if( (size_t)(p_block->p_buffer - p_start) < (size_t)i_prebody
+ || (size_t)(p_end - p_block->p_buffer) < i_body )
{
- /* FIXME: this is really dumb, we should use realloc() */
- block_t *p_rea = block_New( NULL, i_buffer_size );
-
+ block_t *p_rea = block_Alloc( requested );
if( p_rea )
{
- p_rea->i_dts = p_block->i_dts;
- p_rea->i_pts = p_block->i_pts;
- p_rea->i_flags = p_block->i_flags;
- p_rea->i_length = p_block->i_length;
- p_rea->i_rate = p_block->i_rate;
- p_rea->i_samples = p_block->i_samples;
-
- memcpy( p_rea->p_buffer + i_prebody, p_block->p_buffer,
- __MIN( p_block->i_buffer, p_rea->i_buffer - i_prebody ) );
+ BlockMetaCopy( p_rea, p_block );
+ p_rea->p_buffer += i_prebody;
+ p_rea->i_buffer -= i_prebody;
+ memcpy( p_rea->p_buffer, p_block->p_buffer, p_block->i_buffer );
}
-
block_Release( p_block );
-
- return p_rea;
+ if( p_rea == NULL )
+ return NULL;
+ p_block = p_rea;
}
-
- /* We have a very large reserved footer now? Release some of it. */
- if ((p_sys->p_allocated_buffer + p_sys->i_allocated_buffer) -
- (p_block->p_buffer + p_block->i_buffer) > BLOCK_WASTE_SIZE)
+ else
+ /* We have a very large reserved footer now? Release some of it.
+ * XXX it might not preserve the alignment of p_buffer */
+ if( p_end - (p_block->p_buffer + i_body) > BLOCK_WASTE_SIZE )
{
- const size_t news = p_block->i_buffer + 2 * BLOCK_PADDING_SIZE + 16;
- block_sys_t *newb = realloc (p_sys, sizeof (*p_sys) + news);
-
- if (newb != NULL)
+ block_t *p_rea = block_Alloc( requested );
+ if( p_rea )
{
- p_sys = newb;
- p_sys->i_allocated_buffer = news;
- p_block = &p_sys->self;
- p_block->p_buffer = p_sys->p_allocated_buffer + BLOCK_PADDING_SIZE
- + BLOCK_ALIGN
- - ((uintptr_t)p_sys->p_allocated_buffer % BLOCK_ALIGN);
+ BlockMetaCopy( p_rea, p_block );
+ p_rea->p_buffer += i_prebody;
+ p_rea->i_buffer -= i_prebody;
+ memcpy( p_rea->p_buffer, p_block->p_buffer, p_block->i_buffer );
+ block_Release( p_block );
+ p_block = p_rea;
}
}
+ /* NOTE: p_start and p_end are corrupted from this point */
+
+ /* Third, expand payload */
+
+ /* Push payload start */
+ if( i_prebody > 0 )
+ {
+ p_block->p_buffer -= i_prebody;
+ p_block->i_buffer += i_prebody;
+ i_body += i_prebody;
+ i_prebody = 0;
+ }
+
+ /* Expand payload to requested size */
+ p_block->i_buffer = i_body;
+
return p_block;
}
+
+typedef struct
+{
+ block_t self;
+ void *mem;
+} block_heap_t;
+
+static void block_heap_Release (block_t *self)
+{
+ block_heap_t *block = (block_heap_t *)self;
+
+ free (block->mem);
+ free (block);
+}
+
+/**
+ * Creates a block from a heap allocation.
+ * This is provided by LibVLC so that manually heap-allocated blocks can safely
+ * be deallocated even after the origin plugin has been unloaded from memory.
+ *
+ * When block_Release() is called, VLC will free() the specified pointer.
+ *
+ * @param ptr base address of the heap allocation (will be free()'d)
+ * @param addr base address of the useful buffer data
+ * @param length bytes length of the useful buffer data
+ * @return NULL in case of error (ptr free()'d in that case), or a valid
+ * block_t pointer.
+ */
+block_t *block_heap_Alloc (void *ptr, void *addr, size_t length)
+{
+ block_heap_t *block = malloc (sizeof (*block));
+ if (block == NULL)
+ {
+ free (addr);
+ return NULL;
+ }
+
+ block_Init (&block->self, (uint8_t *)addr, length);
+ block->self.pf_release = block_heap_Release;
+ block->mem = ptr;
+ return &block->self;
+}
+
#ifdef HAVE_MMAP
# include <sys/mman.h>
#ifdef WIN32
+# include <io.h>
+#ifdef UNDER_CE
+#define _get_osfhandle(a) ((long) (a))
+#endif
+
static
ssize_t pread (int fd, void *buf, size_t count, off_t offset)
{
if (handle == INVALID_HANDLE_VALUE)
return -1;
- OVERLAPPED olap = { .Offset = offset, .OffsetHigh = (offset >> 32), };
+ OVERLAPPED olap; olap.Offset = offset; olap.OffsetHigh = (offset >> 32);
DWORD written;
/* This braindead API will override the file pointer even if we specify
* an explicit read offset... So do not expect this to mix well with
* Loads a file into a block of memory. If possible a private file mapping is
* created. Otherwise, the file is read normally. On 32-bits platforms, this
* function will not work for very large files, due to memory space
- * constraints.
+ * constraints. Cancellation point.
*
* @param fd file descriptor to load from
* @return a new block with the file content at p_buffer, and file length at
block_t *block = block_Alloc (length);
if (block == NULL)
return NULL;
+ block_cleanup_push (block);
for (size_t i = 0; i < length;)
{
if (len == -1)
{
block_Release (block);
- return NULL;
+ block = NULL;
+ break;
}
i += len;
}
+ vlc_cleanup_pop ();
return block;
}
-/*****************************************************************************
- * block_fifo_t management
- *****************************************************************************/
+/**
+ * @section Thread-safe block queue functions
+ */
+
+/**
+ * Internal state for block queues
+ */
struct block_fifo_t
{
vlc_mutex_t lock; /* fifo data lock */
- vlc_cond_t wait; /* fifo data conditional variable */
+ vlc_cond_t wait; /**< Wait for data */
+ vlc_cond_t wait_room; /**< Wait for queue depth to shrink */
block_t *p_first;
block_t **pp_last;
return NULL;
vlc_mutex_init( &p_fifo->lock );
- vlc_cond_init( NULL, &p_fifo->wait );
+ vlc_cond_init( &p_fifo->wait );
+ vlc_cond_init( &p_fifo->wait_room );
p_fifo->p_first = NULL;
p_fifo->pp_last = &p_fifo->p_first;
p_fifo->i_depth = p_fifo->i_size = 0;
void block_FifoRelease( block_fifo_t *p_fifo )
{
block_FifoEmpty( p_fifo );
+ vlc_cond_destroy( &p_fifo->wait_room );
vlc_cond_destroy( &p_fifo->wait );
vlc_mutex_destroy( &p_fifo->lock );
free( p_fifo );
void block_FifoEmpty( block_fifo_t *p_fifo )
{
- block_t *b;
+ block_t *block;
vlc_mutex_lock( &p_fifo->lock );
- for( b = p_fifo->p_first; b != NULL; )
+ block = p_fifo->p_first;
+ if (block != NULL)
{
- block_t *p_next;
-
- p_next = b->p_next;
- block_Release( b );
- b = p_next;
+ p_fifo->i_depth = p_fifo->i_size = 0;
+ p_fifo->p_first = NULL;
+ p_fifo->pp_last = &p_fifo->p_first;
}
-
- p_fifo->i_depth = p_fifo->i_size = 0;
- p_fifo->p_first = NULL;
- p_fifo->pp_last = &p_fifo->p_first;
+ vlc_cond_broadcast( &p_fifo->wait_room );
vlc_mutex_unlock( &p_fifo->lock );
+
+ while (block != NULL)
+ {
+ block_t *buf;
+
+ buf = block->p_next;
+ block_Release (block);
+ block = buf;
+ }
}
-size_t block_FifoPut( block_fifo_t *p_fifo, block_t *p_block )
+/**
+ * Wait until the FIFO gets below a certain size (if needed).
+ *
+ * Note that if more than one thread writes to the FIFO, you cannot assume that
+ * the FIFO is actually below the requested size upon return (since another
+ * thread could have refilled it already). This is typically not an issue, as
+ * this function is meant for (relaxed) congestion control.
+ *
+ * This function may be a cancellation point and it is cancel-safe.
+ *
+ * @param fifo queue to wait on
+ * @param max_depth wait until the queue has no more than this many blocks
+ * (use SIZE_MAX to ignore this constraint)
+ * @param max_size wait until the queue has no more than this many bytes
+ * (use SIZE_MAX to ignore this constraint)
+ * @return nothing.
+ */
+void block_FifoPace (block_fifo_t *fifo, size_t max_depth, size_t max_size)
{
- size_t i_size = 0;
- vlc_mutex_lock( &p_fifo->lock );
+ vlc_testcancel ();
- do
+ vlc_mutex_lock (&fifo->lock);
+ while ((fifo->i_depth > max_depth) || (fifo->i_size > max_size))
{
- i_size += p_block->i_buffer;
-
- *p_fifo->pp_last = p_block;
- p_fifo->pp_last = &p_block->p_next;
- p_fifo->i_depth++;
- p_fifo->i_size += p_block->i_buffer;
+ mutex_cleanup_push (&fifo->lock);
+ vlc_cond_wait (&fifo->wait_room, &fifo->lock);
+ vlc_cleanup_pop ();
+ }
+ vlc_mutex_unlock (&fifo->lock);
+}
- p_block = p_block->p_next;
+/**
+ * Immediately queue one block at the end of a FIFO.
+ * @param fifo queue
+ * @param block head of a block list to queue (may be NULL)
+ * @return total number of bytes appended to the queue
+ */
+size_t block_FifoPut( block_fifo_t *p_fifo, block_t *p_block )
+{
+ size_t i_size = 0, i_depth = 0;
+ block_t *p_last;
- } while( p_block );
+ if (p_block == NULL)
+ return 0;
+ for (p_last = p_block; ; p_last = p_last->p_next)
+ {
+ i_size += p_last->i_buffer;
+ i_depth++;
+ if (!p_last->p_next)
+ break;
+ }
- /* warn there is data in this fifo */
+ vlc_mutex_lock (&p_fifo->lock);
+ *p_fifo->pp_last = p_block;
+ p_fifo->pp_last = &p_last->p_next;
+ p_fifo->i_depth += i_depth;
+ p_fifo->i_size += i_size;
+ /* We queued at least one block: wake up one read-waiting thread */
vlc_cond_signal( &p_fifo->wait );
vlc_mutex_unlock( &p_fifo->lock );
vlc_mutex_lock( &p_fifo->lock );
if( p_fifo->p_first == NULL )
p_fifo->b_force_wake = true;
- vlc_cond_signal( &p_fifo->wait );
+ vlc_cond_broadcast( &p_fifo->wait );
vlc_mutex_unlock( &p_fifo->lock );
}
+/**
+ * Dequeue the first block from the FIFO. If necessary, wait until there is
+ * one block in the queue. This function is (always) cancellation point.
+ *
+ * @return a valid block, or NULL if block_FifoWake() was called.
+ */
block_t *block_FifoGet( block_fifo_t *p_fifo )
{
block_t *b;
+ vlc_testcancel( );
+
vlc_mutex_lock( &p_fifo->lock );
+ mutex_cleanup_push( &p_fifo->lock );
/* Remember vlc_cond_wait() may cause spurious wakeups
* (on both Win32 and POSIX) */
while( ( p_fifo->p_first == NULL ) && !p_fifo->b_force_wake )
- {
vlc_cond_wait( &p_fifo->wait, &p_fifo->lock );
- }
+ vlc_cleanup_pop();
b = p_fifo->p_first;
p_fifo->b_force_wake = false;
p_fifo->pp_last = &p_fifo->p_first;
}
+ /* We don't know how many threads can queue new packets now. */
+ vlc_cond_broadcast( &p_fifo->wait_room );
vlc_mutex_unlock( &p_fifo->lock );
b->p_next = NULL;
return b;
}
+/**
+ * Peeks the first block in the FIFO.
+ * If necessary, wait until there is one block.
+ * This function is (always) a cancellation point.
+ *
+ * @warning This function leaves the block in the FIFO.
+ * You need to protect against concurrent threads who could dequeue the block.
+ * Preferrably, there should be only one thread reading from the FIFO.
+ *
+ * @return a valid block.
+ */
block_t *block_FifoShow( block_fifo_t *p_fifo )
{
block_t *b;
+ vlc_testcancel( );
+
vlc_mutex_lock( &p_fifo->lock );
+ mutex_cleanup_push( &p_fifo->lock );
- if( p_fifo->p_first == NULL )
- {
+ while( p_fifo->p_first == NULL )
vlc_cond_wait( &p_fifo->wait, &p_fifo->lock );
- }
b = p_fifo->p_first;
- vlc_mutex_unlock( &p_fifo->lock );
-
- return( b );
+ vlc_cleanup_run ();
+ return b;
}
+/* FIXME: not thread-safe */
size_t block_FifoSize( const block_fifo_t *p_fifo )
{
return p_fifo->i_size;
}
+/* FIXME: not thread-safe */
size_t block_FifoCount( const block_fifo_t *p_fifo )
{
return p_fifo->i_depth;
projects / vlc / blobdiff