From patchwork Sun Jul 12 14:44:16 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Laurent Pinchart X-Patchwork-Id: 8745 Return-Path: X-Original-To: parsemail@patchwork.libcamera.org Delivered-To: parsemail@patchwork.libcamera.org Received: from lancelot.ideasonboard.com (lancelot.ideasonboard.com [92.243.16.209]) by patchwork.libcamera.org (Postfix) with ESMTPS id 87411BD792 for ; Sun, 12 Jul 2020 14:44:48 +0000 (UTC) Received: from lancelot.ideasonboard.com (localhost [IPv6:::1]) by lancelot.ideasonboard.com (Postfix) with ESMTP id D9FC36059B; Sun, 12 Jul 2020 16:44:47 +0200 (CEST) Authentication-Results: lancelot.ideasonboard.com; dkim=fail reason="signature verification failed" (1024-bit key; unprotected) header.d=ideasonboard.com header.i=@ideasonboard.com header.b="OHUX6JQ6"; dkim-atps=neutral Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [IPv6:2001:4b98:dc2:55:216:3eff:fef7:d647]) by lancelot.ideasonboard.com (Postfix) with ESMTPS id 9C17960553 for ; Sun, 12 Jul 2020 16:44:45 +0200 (CEST) Received: from pendragon.bb.dnainternet.fi (81-175-216-236.bb.dnainternet.fi [81.175.216.236]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 14B4F514 for ; Sun, 12 Jul 2020 16:44:45 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1594565085; bh=THdfDQdrAo8snr4U/HP5Lz0tEW0rvScablw+oZ3uEXM=; h=From:To:Subject:Date:From; b=OHUX6JQ6twTddXYp4JNnlba5qTdgQ/hV+6tL1eGwgDTDKctTArFP5m4IGPJP6oiVT j6GPy36Fu/I7qalBaB1pv3HK0yVYLAXaRYJ9JjUr41mZCFl0jHZKZpJtCk4vj8G/UL X68QptRpVm+H7jv8eNnTgDV83bRWpxVBuErPDoNY= From: Laurent Pinchart To: libcamera-devel@lists.libcamera.org Date: Sun, 12 Jul 2020 17:44:16 +0300 Message-Id: <20200712144419.21457-1-laurent.pinchart@ideasonboard.com> X-Mailer: git-send-email 2.27.0 MIME-Version: 1.0 Subject: [libcamera-devel] [PATCH 1/4] libcamera: file: Add read/write support X-BeenThere: libcamera-devel@lists.libcamera.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: libcamera-devel-bounces@lists.libcamera.org Sender: "libcamera-devel" Add basic support to read and write data from/to a file, along with retrieving and setting the current read/write position. Signed-off-by: Laurent Pinchart Reviewed-by: Kieran Bingham --- include/libcamera/internal/file.h | 7 ++ src/libcamera/file.cpp | 111 +++++++++++++++++++++++++++++- 2 files changed, 116 insertions(+), 2 deletions(-) diff --git a/include/libcamera/internal/file.h b/include/libcamera/internal/file.h index e3e72132e336..ead94cdf29c9 100644 --- a/include/libcamera/internal/file.h +++ b/include/libcamera/internal/file.h @@ -49,6 +49,12 @@ public: int error() const { return error_; } ssize_t size() const; + off_t pos() const { return pos_; } + off_t seek(off_t pos); + + ssize_t read(const Span &data); + ssize_t write(const Span &data); + Span map(off_t offset = 0, ssize_t size = -1, MapFlag flags = MapNoOption); bool unmap(uint8_t *addr); @@ -61,6 +67,7 @@ private: std::string name_; int fd_; OpenMode mode_; + off_t pos_; int error_; std::map maps_; diff --git a/src/libcamera/file.cpp b/src/libcamera/file.cpp index c471bde3fc68..8bd109090919 100644 --- a/src/libcamera/file.cpp +++ b/src/libcamera/file.cpp @@ -73,7 +73,7 @@ LOG_DEFINE_CATEGORY(File); * before performing I/O operations. */ File::File(const std::string &name) - : name_(name), fd_(-1), mode_(NotOpen), error_(0) + : name_(name), fd_(-1), mode_(NotOpen), pos_(0), error_(0) { } @@ -84,7 +84,7 @@ File::File(const std::string &name) * setFileName(). */ File::File() - : fd_(-1), mode_(NotOpen), error_(0) + : fd_(-1), mode_(NotOpen), pos_(0), error_(0) { } @@ -202,6 +202,7 @@ void File::close() ::close(fd_); fd_ = -1; mode_ = NotOpen; + pos_ = 0; } /** @@ -237,6 +238,112 @@ ssize_t File::size() const return st.st_size; } +/** + * \fn off_t File::pos() const + * \brief Return current read or write position + * + * If the file is closed, this function returns 0. + * + * \return The current read or write position + */ + +/** + * \brief Set the read or write position + * \param[in] pos The desired position + * \return The resulting offset from the beginning of the file on success, or a + * negative error code otherwise + */ +off_t File::seek(off_t pos) +{ + if (!isOpen()) + return -EINVAL; + + off_t ret = lseek(fd_, pos, SEEK_SET); + if (ret < 0) + return -errno; + + pos_ = ret; + return ret; +} + +/** + * \brief Read data from the file + * \param[in] data Memory to read data into + * + * Read at most \a data.size() bytes from the file into \a data.data(), and + * return the number of bytes read. If less data than requested is available, + * the returned byte count may be smaller than the requested size. If no more + * data is available, 0 is returned. + * + * The position of the file as returned by pos() is advanced by the number of + * bytes read. If an error occurs, the position isn't modified. + * + * \return The number of bytes read on success, or a negative error code + * otherwise + */ +ssize_t File::read(const Span &data) +{ + if (!isOpen()) + return -EINVAL; + + size_t readBytes = 0; + ssize_t ret = 0; + + /* Retry in case of interrupted system calls. */ + while (readBytes < data.size()) { + ret = ::read(fd_, data.data() + readBytes, + data.size() - readBytes); + if (ret <= 0) + break; + + readBytes += ret; + } + + if (ret < 0 && !readBytes) + return -errno; + + pos_ += readBytes; + return readBytes; +} + +/** + * \brief Write data to the file + * \param[in] data Memory containing data to be written + * + * Write at most \a data.size() bytes from \a data.data() to the file, and + * return the number of bytes written. If the file system doesn't have enough + * space for the data, the returned byte count may be less than requested. + * + * The position of the file as returned by pos() is advanced by the number of + * bytes written. If an error occurs, the position isn't modified. + * + * \return The number of bytes written on success, or a negative error code + * otherwise + */ +ssize_t File::write(const Span &data) +{ + if (!isOpen()) + return -EINVAL; + + size_t writtenBytes = 0; + + /* Retry in case of interrupted system calls. */ + while (writtenBytes < data.size()) { + ssize_t ret = ::write(fd_, data.data() + writtenBytes, + data.size() - writtenBytes); + if (ret <= 0) + break; + + writtenBytes += ret; + } + + if (data.size() && !writtenBytes) + return -errno; + + pos_ += writtenBytes; + return writtenBytes; +} + /** * \brief Map a region of the file in the process memory * \param[in] offset The region offset within the file