X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=src%2Fmisc%2Fblock.c;h=efa4fce3271774de7be0585d5545d6dad3b53f51;hb=65022ed2467ecb2d0890df5a5af629eb50dd10f4;hp=4f0a04b119c79bdfb52606822aa3033cdc84bf0c;hpb=a2f64f8a853a69dc30d5df100e84792c8c4440b7;p=vlc diff --git a/src/misc/block.c b/src/misc/block.c index 4f0a04b119..efa4fce327 100644 --- a/src/misc/block.c +++ b/src/misc/block.c @@ -2,7 +2,7 @@ * block.c: Data blocks management functions ***************************************************************************** * Copyright (C) 2003-2004 the VideoLAN team - * $Id$ + * Copyright (C) 2007-2009 Rémi Denis-Courmont * * Authors: Laurent Aimar * @@ -30,12 +30,17 @@ #include #include +#include +#include #include "vlc_block.h" -/***************************************************************************** - * Block functions. - *****************************************************************************/ -/* private */ +/** + * @section Block handling functions. + */ + +/** + * Internal state for heap block. + */ struct block_sys_t { block_t self; @@ -54,10 +59,13 @@ static void BlockNoRelease( block_t *b ) 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 @@ -70,10 +78,21 @@ static void BlockRelease( block_t *p_block ) 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 @@ -81,24 +100,41 @@ block_t *block_Alloc( size_t i_size ) { /* 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); - 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 ); +#endif + buf += BLOCK_PADDING; + + 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; } @@ -106,9 +142,10 @@ block_t *block_Alloc( size_t i_size ) 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; @@ -127,68 +164,149 @@ block_t *block_Realloc( block_t *p_block, ssize_t i_prebody, size_t i_body ) 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 @@ -244,6 +362,7 @@ block_t *block_mmap_Alloc (void *addr, size_t length) #ifdef WIN32 +# include #ifdef UNDER_CE #define _get_osfhandle(a) ((long) (a)) #endif @@ -255,7 +374,7 @@ 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 @@ -342,13 +461,18 @@ block_t *block_File (int fd) 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; @@ -365,6 +489,7 @@ block_fifo_t *block_FifoNew( void ) vlc_mutex_init( &p_fifo->lock ); 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; @@ -376,6 +501,7 @@ block_fifo_t *block_FifoNew( void ) 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 ); @@ -383,47 +509,87 @@ void block_FifoRelease( block_fifo_t *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_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 ); - p_next = b->p_next; - block_Release( b ); - b = p_next; + while (block != NULL) + { + block_t *buf; + + buf = block->p_next; + block_Release (block); + block = buf; } +} - p_fifo->i_depth = p_fifo->i_size = 0; - p_fifo->p_first = NULL; - p_fifo->pp_last = &p_fifo->p_first; - vlc_mutex_unlock( &p_fifo->lock ); +/** + * 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) +{ + vlc_testcancel (); + + vlc_mutex_lock (&fifo->lock); + while ((fifo->i_depth > max_depth) || (fifo->i_size > max_size)) + { + mutex_cleanup_push (&fifo->lock); + vlc_cond_wait (&fifo->wait_room, &fifo->lock); + vlc_cleanup_pop (); + } + vlc_mutex_unlock (&fifo->lock); } /** * 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; - vlc_mutex_lock( &p_fifo->lock ); + size_t i_size = 0, i_depth = 0; + block_t *p_last; - while (p_block != NULL) + if (p_block == NULL) + return 0; + for (p_last = p_block; ; p_last = p_last->p_next) { - 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; - - p_block = p_block->p_next; + i_size += p_last->i_buffer; + i_depth++; + if (!p_last->p_next) + break; } - /* We queued one block: wake up one read-waiting thread */ + 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 ); @@ -439,10 +605,18 @@ void block_FifoWake( block_fifo_t *p_fifo ) 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 ); @@ -471,20 +645,35 @@ block_t *block_FifoGet( block_fifo_t *p_fifo ) 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;