From 23039af8427140bafa92dce3021c1f2a14bcfbad Mon Sep 17 00:00:00 2001 From: Lennart Poettering Date: Mon, 20 Jul 2009 15:49:33 +0100 Subject: [PATCH] client: allow zero-copy writing to the stream --- src/pulse/internal.h | 5 ++ src/pulse/stream.c | 145 ++++++++++++++++++++++++++++++++++++++------------- src/pulse/stream.h | 70 ++++++++++++++++++++++--- 3 files changed, 176 insertions(+), 44 deletions(-) diff --git a/src/pulse/internal.h b/src/pulse/internal.h index ec2da85..e069c9e 100644 --- a/src/pulse/internal.h +++ b/src/pulse/internal.h @@ -151,6 +151,11 @@ struct pa_stream { uint32_t device_index; char *device_name; + /* playback */ + pa_memblock *write_memblock; + void *write_data; + + /* recording */ pa_memchunk peek_memchunk; void *peek_data; pa_memblockq *record_memblockq; diff --git a/src/pulse/stream.c b/src/pulse/stream.c index 4055632..5baf5c2 100644 --- a/src/pulse/stream.c +++ b/src/pulse/stream.c @@ -144,12 +144,13 @@ pa_stream *pa_stream_new_with_proplist( s->suspended = FALSE; s->corked = FALSE; + s->write_memblock = NULL; + s->write_data = NULL; + pa_memchunk_reset(&s->peek_memchunk); s->peek_data = NULL; - s->record_memblockq = NULL; - memset(&s->timing_info, 0, sizeof(s->timing_info)); s->timing_info_valid = FALSE; @@ -221,6 +222,11 @@ static void stream_free(pa_stream *s) { stream_unlink(s); + if (s->write_memblock) { + pa_memblock_release(s->write_memblock); + pa_memblock_unref(s->write_data); + } + if (s->peek_memchunk.memblock) { if (s->peek_data) pa_memblock_release(s->peek_memchunk.memblock); @@ -1187,20 +1193,60 @@ int pa_stream_connect_record( return create_stream(PA_STREAM_RECORD, s, dev, attr, flags, NULL, NULL); } +int pa_stream_begin_write( + pa_stream *s, + void **data, + size_t *nbytes) { + + pa_assert(s); + pa_assert(PA_REFCNT_VALUE(s) >= 1); + + PA_CHECK_VALIDITY(s->context, !pa_detect_fork(), PA_ERR_FORKED); + PA_CHECK_VALIDITY(s->context, s->state == PA_STREAM_READY, PA_ERR_BADSTATE); + PA_CHECK_VALIDITY(s->context, s->direction == PA_STREAM_PLAYBACK || s->direction == PA_STREAM_UPLOAD, PA_ERR_BADSTATE); + PA_CHECK_VALIDITY(s->context, data, PA_ERR_INVALID); + PA_CHECK_VALIDITY(s->context, nbytes && *nbytes != 0, PA_ERR_INVALID); + + if (!s->write_memblock) { + s->write_memblock = pa_memblock_new(s->context->mempool, *nbytes); + s->write_data = pa_memblock_acquire(s->write_memblock); + } + + *data = s->write_data; + *nbytes = pa_memblock_get_length(s->write_memblock); + + return 0; +} + +int pa_stream_cancel_write( + pa_stream *s) { + + pa_assert(s); + pa_assert(PA_REFCNT_VALUE(s) >= 1); + + PA_CHECK_VALIDITY(s->context, !pa_detect_fork(), PA_ERR_FORKED); + PA_CHECK_VALIDITY(s->context, s->state == PA_STREAM_READY, PA_ERR_BADSTATE); + PA_CHECK_VALIDITY(s->context, s->direction == PA_STREAM_PLAYBACK || s->direction == PA_STREAM_UPLOAD, PA_ERR_BADSTATE); + PA_CHECK_VALIDITY(s->context, s->write_memblock, PA_ERR_BADSTATE); + + pa_assert(s->write_data); + + pa_memblock_release(s->write_memblock); + pa_memblock_unref(s->write_memblock); + s->write_memblock = NULL; + s->write_data = NULL; + + return 0; +} + int pa_stream_write( pa_stream *s, const void *data, size_t length, - void (*free_cb)(void *p), + pa_free_cb_t free_cb, int64_t offset, pa_seek_mode_t seek) { - pa_memchunk chunk; - pa_seek_mode_t t_seek; - int64_t t_offset; - size_t t_length; - const void *t_data; - pa_assert(s); pa_assert(PA_REFCNT_VALUE(s) >= 1); pa_assert(data); @@ -1210,46 +1256,71 @@ int pa_stream_write( PA_CHECK_VALIDITY(s->context, s->direction == PA_STREAM_PLAYBACK || s->direction == PA_STREAM_UPLOAD, PA_ERR_BADSTATE); PA_CHECK_VALIDITY(s->context, seek <= PA_SEEK_RELATIVE_END, PA_ERR_INVALID); PA_CHECK_VALIDITY(s->context, s->direction == PA_STREAM_PLAYBACK || (seek == PA_SEEK_RELATIVE && offset == 0), PA_ERR_INVALID); + PA_CHECK_VALIDITY(s->context, + !s->write_memblock || + ((data >= s->write_data) && + ((const char*) data + length <= (const char*) s->write_data + pa_memblock_get_length(s->write_memblock))), + PA_ERR_INVALID); + PA_CHECK_VALIDITY(s->context, !free_cb || !s->write_memblock, PA_ERR_INVALID); - if (length <= 0) - return 0; + if (s->write_memblock) { + pa_memchunk chunk; - t_seek = seek; - t_offset = offset; - t_length = length; - t_data = data; + /* pa_stream_write_begin() was called before */ - while (t_length > 0) { + pa_memblock_release(s->write_memblock); - chunk.index = 0; + chunk.memblock = s->write_memblock; + chunk.index = (const char *) data - (const char *) s->write_data; + chunk.length = length; - if (free_cb && !pa_pstream_get_shm(s->context->pstream)) { - chunk.memblock = pa_memblock_new_user(s->context->mempool, (void*) t_data, t_length, free_cb, 1); - chunk.length = t_length; - } else { - void *d; + s->write_memblock = NULL; + s->write_data = NULL; - chunk.length = PA_MIN(t_length, pa_mempool_block_size_max(s->context->mempool)); - chunk.memblock = pa_memblock_new(s->context->mempool, chunk.length); + pa_pstream_send_memblock(s->context->pstream, s->channel, offset, seek, &chunk); + pa_memblock_unref(chunk.memblock); - d = pa_memblock_acquire(chunk.memblock); - memcpy(d, t_data, chunk.length); - pa_memblock_release(chunk.memblock); - } + } else { + pa_seek_mode_t t_seek = seek; + int64_t t_offset = offset; + size_t t_length = length; + const void *t_data = data; - pa_pstream_send_memblock(s->context->pstream, s->channel, t_offset, t_seek, &chunk); + /* pa_stream_write_begin() was not called before */ - t_offset = 0; - t_seek = PA_SEEK_RELATIVE; + while (t_length > 0) { + pa_memchunk chunk; - t_data = (const uint8_t*) t_data + chunk.length; - t_length -= chunk.length; + chunk.index = 0; - pa_memblock_unref(chunk.memblock); - } + if (free_cb && !pa_pstream_get_shm(s->context->pstream)) { + chunk.memblock = pa_memblock_new_user(s->context->mempool, (void*) t_data, t_length, free_cb, 1); + chunk.length = t_length; + } else { + void *d; + + chunk.length = PA_MIN(t_length, pa_mempool_block_size_max(s->context->mempool)); + chunk.memblock = pa_memblock_new(s->context->mempool, chunk.length); + + d = pa_memblock_acquire(chunk.memblock); + memcpy(d, t_data, chunk.length); + pa_memblock_release(chunk.memblock); + } - if (free_cb && pa_pstream_get_shm(s->context->pstream)) - free_cb((void*) data); + pa_pstream_send_memblock(s->context->pstream, s->channel, t_offset, t_seek, &chunk); + + t_offset = 0; + t_seek = PA_SEEK_RELATIVE; + + t_data = (const uint8_t*) t_data + chunk.length; + t_length -= chunk.length; + + pa_memblock_unref(chunk.memblock); + } + + if (free_cb && pa_pstream_get_shm(s->context->pstream)) + free_cb((void*) data); + } /* This is obviously wrong since we ignore the seeking index . But * that's OK, the server side applies the same error */ diff --git a/src/pulse/stream.h b/src/pulse/stream.h index 49c132a..fecc587 100644 --- a/src/pulse/stream.h +++ b/src/pulse/stream.h @@ -418,15 +418,71 @@ int pa_stream_connect_record( /** Disconnect a stream from a source/sink */ int pa_stream_disconnect(pa_stream *s); -/** Write some data to the server (for playback sinks), if free_cb is - * non-NULL this routine is called when all data has been written out - * and an internal reference to the specified data is kept, the data - * is not copied. If NULL, the data is copied into an internal - * buffer. The client my freely seek around in the output buffer. For +/** Prepare writing data to the server (for playback streams). This + * function may be used to optimize the number of memory copies when + * doing playback ("zero-copy"). It is recommended to call this + * function before each call to pa_stream_write(). Pass in the address + * to a pointer and an address of the number of bytes you want to + * write. On return the two values will contain a pointer where you + * can place the data to write and the maximum number of bytes you can + * write. On return *nbytes can be larger or have the same value as + * you passed in. You need to be able to handle both cases. Accessing + * memory beyond the returned *nbytes value is invalid. Acessing the + * memory returned after the following pa_stream_write() or + * pa_stream_cancel_write() is invalid. On invocation only *nbytes + * needs to be initialized, on return both *data and *nbytes will be + * valid. If you place (size_t) -1 in *nbytes on invocation the memory + * size will be chosen automatically (which is recommended to + * do). After placing your data in the memory area returned call + * pa_stream_write() with data set to an address within this memory + * area and an nbytes value that is smaller or equal to what was + * returned by this function to actually execute the write. An + * invocation of pa_stream_write() should follow "quickly" on + * pa_stream_begin_write(). It is not recommended letting an unbounded + * amount of time pass after calling pa_stream_begin_write() and + * before calling pa_stream_write(). If you want to cancel a + * previously called pa_stream_begin_write() without calling + * pa_stream_write() use pa_stream_cancel_write() instead. Calling + * pa_stream_begin_write() twice without calling pa_stream_write() or + * pa_stream_cancel_write() in between will return exactly the same + * pointer/nbytes values.\since 0.9.16 */ +int pa_stream_begin_write( + pa_stream *p, + void **data, + size_t *nbytes); + +/** Reverses the effect of pa_stream_begin_write() dropping all data + * that has already been placed in the memory area returned by + * pa_stream_begin_write(). Only valid to call if + * pa_stream_begin_write() was called before and neither + * pa_stream_cancel_write() nor pa_stream_write() have been called + * yet. Accessing the memory previously returned by + * pa_stream_begin_write() after this call is invalid. Any further + * explicit freeing of the memory area is not necessary. \since + * 0.9.16 */ +int pa_stream_cancel_write( + pa_stream *p); + +/** Write some data to the server (for playback streams), if free_cb + * is non-NULL this routine is called when all data has been written + * out and an internal reference to the specified data is kept, the + * data is not copied. If NULL, the data is copied into an internal + * buffer. The client may freely seek around in the output buffer. For * most applications passing 0 and PA_SEEK_RELATIVE as arguments for * offset and seek should be useful. Afte ther write call succeeded * the write index will be a the position after where this chunk of - * data has been written to. */ + * data has been written to. + * + * As an optimization for avoiding needless memory copies you may call + * pa_stream_begin_write() before this call and then place your audio + * data directly in the memory area returned by that call. Then, pass + * a pointer to that memory area to pa_stream_write(). After the + * invocation of pa_stream_write() the memory area may no longer be + * accessed. Any further explicit freeing of the memory area is not + * necessary. It is OK to write the memory area returned by + * pa_stream_begin_write() only partially with this call, skipping + * bytes both at the end and at the beginning of the reserved memory + * area.*/ int pa_stream_write( pa_stream *p /**< The stream to use */, const void *data /**< The data to write */, @@ -435,7 +491,7 @@ int pa_stream_write( int64_t offset, /**< Offset for seeking, must be 0 for upload streams */ pa_seek_mode_t seek /**< Seek mode, must be PA_SEEK_RELATIVE for upload streams */); -/** Read the next fragment from the buffer (for recording). +/** Read the next fragment from the buffer (for recording streams). * data will point to the actual data and length will contain the size * of the data in bytes (which can be less than a complete framgnet). * Use pa_stream_drop() to actually remove the data from the -- 2.7.4