From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ffbox0-bg.mplayerhq.hu (ffbox0-bg.ffmpeg.org [79.124.17.100]) by master.gitmailbox.com (Postfix) with ESMTP id D448542B14 for ; Tue, 11 Jan 2022 20:50:05 +0000 (UTC) Received: from [127.0.1.1] (localhost [127.0.0.1]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTP id BF88E68AF9C; Tue, 11 Jan 2022 22:47:48 +0200 (EET) Received: from mail0.khirnov.net (red.khirnov.net [176.97.15.12]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTPS id 3A3FA68AF0D for ; Tue, 11 Jan 2022 22:47:32 +0200 (EET) Received: from localhost (localhost [IPv6:::1]) by mail0.khirnov.net (Postfix) with ESMTP id 558BD240511 for ; Tue, 11 Jan 2022 21:47:28 +0100 (CET) Received: from mail0.khirnov.net ([IPv6:::1]) by localhost (mail0.khirnov.net [IPv6:::1]) (amavisd-new, port 10024) with ESMTP id UnfO-GVVIlj5 for ; Tue, 11 Jan 2022 21:47:27 +0100 (CET) Received: from libav.khirnov.net (libav.khirnov.net [IPv6:2a00:c500:561:201::7]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256 client-signature RSA-PSS (2048 bits) client-digest SHA256) (Client CN "libav.khirnov.net", Issuer "smtp.khirnov.net SMTP CA" (verified OK)) by mail0.khirnov.net (Postfix) with ESMTPS id 7BD0824050B for ; Tue, 11 Jan 2022 21:47:25 +0100 (CET) Received: by libav.khirnov.net (Postfix, from userid 1000) id 0A00A3A0804; Tue, 11 Jan 2022 21:47:25 +0100 (CET) From: Anton Khirnov To: ffmpeg-devel@ffmpeg.org Date: Tue, 11 Jan 2022 21:45:43 +0100 Message-Id: <20220111204610.14262-8-anton@khirnov.net> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20220111204610.14262-1-anton@khirnov.net> References: <20220111204610.14262-1-anton@khirnov.net> MIME-Version: 1.0 Subject: [FFmpeg-devel] [PATCH 08/35] lavu/fifo: add new FIFO read/peek functions X-BeenThere: ffmpeg-devel@ffmpeg.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: FFmpeg development discussions and patches List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: FFmpeg development discussions and patches Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: ffmpeg-devel-bounces@ffmpeg.org Sender: "ffmpeg-devel" Archived-At: List-Archive: List-Post: As for writing, use separate functions for reading to a buffer and a callback. Allow the callbacks to limit the amount of data read, similarly to what is done for writing. Consistently use size_t for sizes. --- doc/APIchanges | 3 ++- libavutil/fifo.c | 68 ++++++++++++++++++++++++++++++++++++++++++++++++ libavutil/fifo.h | 60 ++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 130 insertions(+), 1 deletion(-) diff --git a/doc/APIchanges b/doc/APIchanges index 0b179c30e5..f64759d69d 100644 --- a/doc/APIchanges +++ b/doc/APIchanges @@ -19,7 +19,8 @@ API changes, most recent first: Operations on FIFOs created with this function on these elements rather than bytes. Add av_fifo_elem_size(), av_fifo_can_read(), av_fifo_can_write(), - av_fifo_grow2(), av_fifo_drain2(), av_fifo_write(), av_fifo_write_from_cb(). + av_fifo_grow2(), av_fifo_drain2(), av_fifo_write(), av_fifo_write_from_cb(), + av_fifo_read(), av_fifo_read_to_cb(), av_fifo_peek(), av_fifo_peek_to_cb(). 2022-01-xx - xxxxxxxxxx - lavu fifo.h Access to all AVFifoBuffer members is deprecated. The struct will diff --git a/libavutil/fifo.c b/libavutil/fifo.c index 1d94fff457..ea944bc936 100644 --- a/libavutil/fifo.c +++ b/libavutil/fifo.c @@ -265,6 +265,74 @@ int av_fifo_write_from_cb(AVFifoBuffer *f, AVFifoCB read_cb, return fifo_write_common(f, NULL, nb_elems, read_cb, opaque); } +static int fifo_peek_common(const AVFifoBuffer *f, uint8_t *buf, size_t *nb_elems, + size_t offset, AVFifoCB write_cb, void *opaque) +{ + const FifoBuffer *fb = (FifoBuffer*)f; + size_t to_read = *nb_elems; + size_t offset_r = fb->offset_r; + int ret = 0; + + if (offset > av_fifo_can_read(f) || + to_read > av_fifo_can_read(f) - offset) { + *nb_elems = 0; + return AVERROR(EINVAL); + } + + if (offset_r >= fb->nb_elems - offset) + offset_r -= fb->nb_elems - offset; + else + offset_r += offset; + + do { + size_t len = FFMIN(fb->nb_elems - offset_r, to_read); + uint8_t *rptr = f->buffer + offset_r * fb->elem_size; + + if (write_cb) { + ret = write_cb(opaque, rptr, &len); + if (ret < 0 || len == 0) + break; + } else { + memcpy(buf, rptr, len * fb->elem_size); + buf += len * fb->elem_size; + } + offset_r += len; + if (offset_r >= fb->nb_elems) + offset_r = 0; + to_read -= len; + } while (to_read > 0); + + *nb_elems -= to_read; + + return ret; +} + +int av_fifo_read(AVFifoBuffer *f, void *buf, size_t nb_elems) +{ + int ret = fifo_peek_common(f, buf, &nb_elems, 0, NULL, NULL); + av_fifo_drain2(f, nb_elems); + return ret; +} + +int av_fifo_read_to_cb(AVFifoBuffer *f, AVFifoCB write_cb, + void *opaque, size_t *nb_elems) +{ + int ret = fifo_peek_common(f, NULL, nb_elems, 0, write_cb, opaque); + av_fifo_drain2(f, *nb_elems); + return ret; +} + +int av_fifo_peek(AVFifoBuffer *f, void *buf, size_t nb_elems, size_t offset) +{ + return fifo_peek_common(f, buf, &nb_elems, offset, NULL, NULL); +} + +int av_fifo_peek_to_cb(AVFifoBuffer *f, AVFifoCB write_cb, void *opaque, + size_t *nb_elems, size_t offset) +{ + return fifo_peek_common(f, NULL, nb_elems, offset, write_cb, opaque); +} + int av_fifo_realloc2(AVFifoBuffer *f, unsigned int new_size) { FifoBuffer *fb = (FifoBuffer*)f; diff --git a/libavutil/fifo.h b/libavutil/fifo.h index ac1245ff39..c7be5e8f7d 100644 --- a/libavutil/fifo.h +++ b/libavutil/fifo.h @@ -189,6 +189,66 @@ int av_fifo_write(AVFifoBuffer *f, const void *buf, size_t nb_elems); int av_fifo_write_from_cb(AVFifoBuffer *f, AVFifoCB read_cb, void *opaque, size_t *nb_elems); +/** + * Read data from a FIFO. + * + * @param f the FIFO buffer + * @param buf Buffer to store the data. nb_elems * av_fifo_elem_size(f) bytes + * will be written into buf. + * @param nb_elems number of elements to read from FIFO + * + * @return a non-negative number on success, a negative error code on failure + */ +int av_fifo_read(AVFifoBuffer *f, void *buf, size_t nb_elems); + +/** + * Feed data from a FIFO into a user-provided callback. + * + * @param f the FIFO buffer + * @param write_cb Callback the data will be supplied to. May be called + * multiple times. + * @param opaque opaque user data to be provided to write_cb + * @param nb_elems Should point to the maximum number of elements that can be + * read. Will be updated to contain the total number of elements + * actually sent to the callback. + * + * @return non-negative number on success, a negative error code on failure + */ +int av_fifo_read_to_cb(AVFifoBuffer *f, AVFifoCB write_cb, + void *opaque, size_t *nb_elems); + +/** + * Read data from a FIFO without modifying FIFO state. + * + * @param f the FIFO buffer + * @param buf Buffer to store the data. nb_elems * av_fifo_elem_size(f) bytes + * will be written into buf. + * @param nb_elems number of elements to read from FIFO + * @param offset number of initial elements to skip; offset + nb_elems must not + * be larger than av_fifo_can_read(f). + * + * @return a non-negative number on success, a negative error code on failure + */ +int av_fifo_peek(AVFifoBuffer *f, void *buf, size_t nb_elems, size_t offset); + +/** + * Feed data from a FIFO into a user-provided callback. + * + * @param f the FIFO buffer + * @param write_cb Callback the data will be supplied to. May be called + * multiple times. + * @param opaque opaque user data to be provided to write_cb + * @param nb_elems Should point to the maximum number of elements that can be + * read. Will be updated to contain the total number of elements + * actually sent to the callback. + * @param offset number of initial elements to skip; offset + *nb_elems must not + * be larger than av_fifo_can_read(f). + * + * @return a non-negative number on success, a negative error code on failure + */ +int av_fifo_peek_to_cb(AVFifoBuffer *f, AVFifoCB write_cb, void *opaque, + size_t *nb_elems, size_t offset); + /** * Discard the specified amount of data from an AVFifoBuffer. * @param size number of elements to discard, MUST NOT be larger than -- 2.33.0 _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".