From patchwork Tue Sep 24 17:24:45 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jacopo Mondi X-Patchwork-Id: 2002 Return-Path: Received: from relay3-d.mail.gandi.net (relay3-d.mail.gandi.net [217.70.183.195]) by lancelot.ideasonboard.com (Postfix) with ESMTPS id 9EF7A6237C for ; Tue, 24 Sep 2019 19:23:30 +0200 (CEST) X-Originating-IP: 213.45.248.89 Received: from uno.homenet.telecomitalia.it (host89-248-dynamic.45-213-r.retail.telecomitalia.it [213.45.248.89]) (Authenticated sender: jacopo@jmondi.org) by relay3-d.mail.gandi.net (Postfix) with ESMTPSA id ACB8E60009 for ; Tue, 24 Sep 2019 17:23:29 +0000 (UTC) From: Jacopo Mondi To: libcamera-devel@lists.libcamera.org Date: Tue, 24 Sep 2019 19:24:45 +0200 Message-Id: <20190924172503.30864-4-jacopo@jmondi.org> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20190924172503.30864-1-jacopo@jmondi.org> References: <20190924172503.30864-1-jacopo@jmondi.org> MIME-Version: 1.0 Subject: [libcamera-devel] [PATCH 03/21] libcamera: Implement serialization helper class 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: , X-List-Received-Date: Tue, 24 Sep 2019 17:23:30 -0000 Define and implement a Serializer class which provides static operations used to serialize and de-serialize DataValue and DataInfo instances to and from a memory buffers. The helpers implementation define the binary serialization format to which data are dumped to and restored from. Signed-off-by: Jacopo Mondi --- src/libcamera/include/meson.build | 1 + src/libcamera/include/serializer.h | 93 +++++++ src/libcamera/meson.build | 1 + src/libcamera/serializer.cpp | 420 +++++++++++++++++++++++++++++ 4 files changed, 515 insertions(+) create mode 100644 src/libcamera/include/serializer.h create mode 100644 src/libcamera/serializer.cpp diff --git a/src/libcamera/include/meson.build b/src/libcamera/include/meson.build index 933be8543a8d..3bec594c3b3d 100644 --- a/src/libcamera/include/meson.build +++ b/src/libcamera/include/meson.build @@ -15,6 +15,7 @@ libcamera_headers = files([ 'message.h', 'pipeline_handler.h', 'process.h', + 'serializer.h', 'thread.h', 'utils.h', 'v4l2_controls.h', diff --git a/src/libcamera/include/serializer.h b/src/libcamera/include/serializer.h new file mode 100644 index 000000000000..19978bc0375f --- /dev/null +++ b/src/libcamera/include/serializer.h @@ -0,0 +1,93 @@ +/* SPDX-License-Identifier: LGPL-2.1-or-later */ +/* + * Copyright (C) 2019, Google Inc. + * + * serializer.h - Data serializer helpers + */ +#ifndef __LIBCAMERA_SERIALIZER_H__ +#define __LIBCAMERA_SERIALIZER_H__ + +#include +#include +#include + +#include + +#include "utils.h" + +namespace libcamera { + +class Serializer +{ +public: + static constexpr unsigned int BLOB_ALIGN_BYTES = 8; + static constexpr unsigned int BLOB_ALIGN(size_t s) + { + return ALIGN(s, BLOB_ALIGN_BYTES); + } + + /* + * These offset define the serialization format. + * Keep the total headers size 8 bytes aligned. + */ + static constexpr unsigned int VALUE_BLOB_TYPE_OFFS = 4; + static constexpr uint8_t *VALUE_BLOB_TYPE(uint8_t *b) + { + + return b + VALUE_BLOB_TYPE_OFFS; + } + + static constexpr unsigned int VALUE_BLOB_SIZE_OFFS = 8; + static constexpr uint8_t *VALUE_BLOB_SIZE(uint8_t *b) + { + return b + VALUE_BLOB_SIZE_OFFS; + } + + static constexpr unsigned int VALUE_BLOB_DATA_OFFS = 16; + static constexpr uint8_t *VALUE_BLOB_DATA(uint8_t *b) + { + return b + VALUE_BLOB_DATA_OFFS; + } + + static constexpr unsigned int INFO_BLOB_TYPE_OFFS = 4; + static constexpr uint8_t *INFO_BLOB_TYPE(uint8_t *b) + { + return b + INFO_BLOB_TYPE_OFFS; + } + + static constexpr unsigned int INFO_BLOB_SIZE_OFFS = 8; + static constexpr uint8_t *INFO_BLOB_SIZE(uint8_t *b) + { + return b + INFO_BLOB_SIZE_OFFS; + } + + static constexpr unsigned int INFO_BLOB_DATA_OFFS = 16; + static constexpr uint8_t *INFO_BLOB_DATA(uint8_t *b) + { + return b + INFO_BLOB_DATA_OFFS; + } + + using DataValueTuple = std::tuple; + using DataInfoTuple = std::tuple; + + static int serialize(unsigned int id, const DataValue &value, + uint8_t *buffer); + static DataValueTuple deserializeValue(uint8_t *buffer); + + static int serialize(unsigned int id, const DataInfo &info, + uint8_t *buffer); + static DataInfoTuple deserializeInfo(uint8_t *buffer); + + static unsigned int size(const DataValue &value); + static unsigned int size(const DataInfo &value); + +private: + static unsigned int dumpValue(const DataValue &value, DataType type, + uint8_t *b); + static DataValue loadValue(DataType type, uint8_t *b); + static DataInfo loadInfo(DataType type, uint8_t *b); +}; + +} /* namespace libcamera */ + +#endif /* __LIBCAMERA_SERIALIZER_H__ */ diff --git a/src/libcamera/meson.build b/src/libcamera/meson.build index 973b20269943..0f6f97305e4f 100644 --- a/src/libcamera/meson.build +++ b/src/libcamera/meson.build @@ -28,6 +28,7 @@ libcamera_sources = files([ 'request.cpp', 'signal.cpp', 'serializable.cpp', + 'serializer.cpp', 'stream.cpp', 'thread.cpp', 'timer.cpp', diff --git a/src/libcamera/serializer.cpp b/src/libcamera/serializer.cpp new file mode 100644 index 000000000000..d624d277434b --- /dev/null +++ b/src/libcamera/serializer.cpp @@ -0,0 +1,420 @@ +/* SPDX-License-Identifier: LGPL-2.1-or-later */ +/* + * Copyright (C) 2019, Google Inc. + * + * serializer.h - Data serializer helpers + */ + +#include "serializer.h" + +#include + +#include + +/** + * \file serializer.h + * \brief Helper class for serialization of values and information + */ + +namespace libcamera { + +/** + * \class Serializer + * \brief Helper class that provides operations to serialize values and + * information to memory buffers + * + * The Serializer class provides helper methods to serialize to binary format + * DataValue and DataInfo associated with a numerical identifier. + * + * A data is serialized to a memory buffer using the serialize() operation. It + * is responsability of the caller to provide a pointer to an opportunely + * allocated memory area, with enough space reserved to contain the whole data + * blob representation. The memory size required to contain all serialized data + * could be esitameted by using the size() operation when iterating on them. + */ + +/** + * \var Serializer::BLOB_ALIGN_BYTES + * \brief The blob alignement, in bytes + */ + +/** + * \fn Serializer::BLOB_ALIGN() + * \brief Align a size \a s to BLOB_ALIGN_BYTES + * \param[in] s The size to align + * \return Size \a s aligned to BLOB_ALIGN_BYTES + */ + +/** + * \var Serializer::VALUE_BLOB_TYPE_OFFS + * \brief The offset from the blob start where the value type is encoded + */ + +/** + * \fn Serializer::VALUE_BLOB_TYPE() + * \brief Return the memory location where the value type is encoded in buffer + * \a b + * \param[in] b The memory buffer containing a serialized value + * \return The memory location in buffer \b where the type information is + * encoded + */ + +/** + * \var Serializer::VALUE_BLOB_SIZE_OFFS + * \brief The offset from the blob start where the value size is encoded + */ + +/** + * \fn Serializer::VALUE_BLOB_SIZE() + * \brief Return the memory location where the value size is encoded in buffer + * \a b + * \param[in] b The memory buffer containing a serialized value + * \return The memory location in buffer \b where the size information is + * encoded + */ + +/** + * \var Serializer::VALUE_BLOB_DATA_OFFS + * \brief The offset from the blob start where the value data is encoded + */ + +/** + * \fn Serializer::VALUE_BLOB_DATA() + * \brief Return the memory location where the value data is encoded in buffer + * \a b + * \param[in] b The memory buffer containing a serialized value + * \return The memory location in buffer \b where the data information is + * encoded + */ + +/** + * \var Serializer::INFO_BLOB_TYPE_OFFS + * \brief The offset from the blob start where the value type is encoded + */ + +/** + * \fn Serializer::INFO_BLOB_TYPE() + * \brief Return the memory location where the value type is encoded in buffer + * \a b + * \param[in] b The memory buffer containing a serialized value + * \return The memory location in buffer \b where the type information is + * encoded + */ + +/** + * \var Serializer::INFO_BLOB_SIZE_OFFS + * \brief The offset from the blob start where the value size is encoded + */ + +/** + * \fn Serializer::INFO_BLOB_SIZE() + * \brief Return the memory location where the value size is encoded in buffer + * \a b + * \param[in] b The memory buffer containing a serialized value + * \return The memory location in buffer \b where the size information is + * encoded + */ + +/** + * \var Serializer::INFO_BLOB_DATA_OFFS + * \brief The offset from the blob start where the value data is encoded + */ + +/** + * \fn Serializer::INFO_BLOB_DATA() + * \brief Return the memory location where the value data is encoded in buffer + * \a b + * \param[in] b The memory buffer containing a serialized value + * \return The memory location in buffer \b where the data information is + * encoded + */ + +/** + * \typedef Serializer::DataValueTuple + * \brief A tuple that contains a numeric id, a DataValue and a size + * + * DataTupleValue is used to return the content of a DataValue de-serialization + * operation. + */ + +/** + * \typedef Serializer::DataInfoTuple + * \brief A tuple that contains a numeric id, a DataInfo and a size + * + * DataTupleInfo is used to return the content of a DataInfo de-serialization + * operation. + */ + +/** + * \var Serializer::BLOB_ALIGN_BYTES + * \brief Memory alignement of the serialized data in bytes + */ + +/** + * \brief Serialize a data value into a memory buffer + * \param[in] id The identifier associated with the DataValue + * \param[in] value The DataValue to serialize + * \param[in] buffer The memory area where to serialize the data blob + * + * A data value is serialized to the following binary sections: + * - id: the identifier provided to the operation + * - type: the DataType of the DataValue provided to the operation + * - size: the size in bytes of the data contained in the DataValue provided + * the operation + * - data: the data contained in the DataValue provided to the operation + * - padding (optional): padding bytes to guarantee alignment to 64-bits + * boundary + * + * The data value is serialized to the following binary format: + * + * Bytes + * Offset: 0 4 8 16 [16 + size] + * +----+----+--------+----- ... -----+--- ... ----+ + * Entry: | id |type| size | data | padding | + * +----+----+--------+----- ... ------+--- ... ---+ + * + * \----- HEADER ----\---- DATA ----\--- PADDING ---\ + * + * The operation returns the total number of data written into \a buffer, + * which is guaranteed to be aligned to Serializer::BLOB_ALIGN_BYTES boundary. + * + * The memory buffer pointer \a b is not advanced during serialization, and is + * responsibility of the caller to advance it using the returned size to the + * next memory location where to serialize data. + * + * \return The number of bytes written in \a buffer, or a negative error code + * in case of errors + */ +int Serializer::serialize(unsigned int id, const DataValue &value, + uint8_t *buffer) +{ + if (!buffer) + return -ENOMEM; + + DataType type = value.type(); + uint8_t *b = buffer; + + *reinterpret_cast(b) = id; + *reinterpret_cast(VALUE_BLOB_TYPE(b)) = type; + *reinterpret_cast(VALUE_BLOB_SIZE(b)) = BLOB_ALIGN(value.size()); + + dumpValue(value, type, VALUE_BLOB_DATA(b)); + + return Serializer::size(value); +} + +/** + * \brief De-serialize a memory buffer to a tuple containing a DataValue + * \param[in] buffer The buffer containing data to de-serialize + * + * De-serialize a data value and its associated id from the memory buffer + * \a b. The de-serialized data are expected to be have been serialized using + * the serialize(unsigned int id, const DataValue &value, uint8_t *buffer) + * operation, which dumps data to the memory in the format known to this + * operation. + * + * The de-serialized data are returned in a tuple which contains: + * - id: the id associated with the de-serialized DataValue + * - value: the de-serialized DataValue + * - size: the size (in bytes) occupied by the serialized data in the memory + * buffer + * + * The memory buffer pointer \a b is not advanced during de-serialization, and + * it is responsibility of the caller to advance it using the returned size to + * the next memory location containing data to de-serialize. + * + * \return A tuple containing the id associated with the de-serialized data, the + * data value itself and the size of the size of the de-serialized memory area + */ +Serializer::DataValueTuple Serializer::deserializeValue(uint8_t *buffer) +{ + if (!buffer) + return {}; + + uint8_t *b = buffer; + unsigned int id = *reinterpret_cast(b); + DataType type = *reinterpret_cast(VALUE_BLOB_TYPE(b)); + size_t size = *reinterpret_cast(VALUE_BLOB_SIZE(b)); + + b = VALUE_BLOB_DATA(b); + return std::make_tuple( + std::forward(id), loadValue(type, b), + std::forward(size + VALUE_BLOB_DATA_OFFS)); +} + +/** + * \brief Serialize a data info into a memory buffer + * \param[in] id The identifier associated with the DataValue + * \param[in] info The DataInfo to serialize + * \param[in] buffer The memory area where to serialize the data blob + * + * A data info is serialized to the following binary sections: + * - id: the identifier provided to the operation + * - type: the DataType of the data this info refers to + * - size: the size in bytes of the data contained in the DataInfo provided + * to the operation + * - data: the data contained in the DataInfo provided to the operation: + * - min (DataValue of type 'type') + * - max (DataValue of type 'type') + * + * The data value is serialized to the following binary format: + * + * Bytes + * Offset: 0 4 8 16 [16 + size] + * +----+----+--------+- ... -+- ... -+ + * Entry: | id |type| size | min | max | + * +----+----+--------+- ... -+- ... -+ + * + * \----- HEADER -----\---- DATA ----\ + * + * The operation returns the total number of data written into \a buffer, + * which is guaranteed to be aligned to Serializer::BLOB_ALIGN_BYTES boundary. + * + * \return The number of bytes written in \a buffer, or a negative error code + * in case of errors + */ +int Serializer::serialize(unsigned int id, const DataInfo &info, + uint8_t *buffer) +{ + if (!buffer) + return -ENOMEM; + + DataType type = info.min().type(); + uint8_t *b = buffer; + + *reinterpret_cast(b) = id; + *reinterpret_cast(INFO_BLOB_TYPE(b)) = type; + *reinterpret_cast(INFO_BLOB_SIZE(b)) = BLOB_ALIGN(DataSize[type]) + + BLOB_ALIGN(DataSize[type]); + + b = INFO_BLOB_DATA(b); + b += dumpValue(info.min(), type, b); + b += dumpValue(info.max(), type, b); + + return Serializer::size(info); +} + +/** + * \brief De-serialize a memory buffer to a tuple containing a DataInfo + * \param[in] buffer The buffer containing data to de-serialize + * + * De-serialize a data value and its associated id from the memory buffer + * \a b. The de-serialized data are expected to be have been serialized using + * the serialize(unsigned int id, const DataInfo &info, uint8_t *buffer) + * operation, which dumps data to the memory in the format known to this + * operation. + * + * The de-serialized data are returned in a tuple which contains: + * - id: the id associated with the de-serialized DataValue + * - info: the de-serialized DataInfo + * - size: the size (in bytes) occupied by the serialized data in the memory + * buffer + * + * The memory buffer pointer \a b is not advanced during de-serialization, and + * it is responsibility of the caller to advance it using the returned size to + * the next memory location containing data to de-serialize. + * + * \return A tuple containing the id associated with the de-serialized data, the + * data value itself and the size of the size of the de-serialized memory area + */ +Serializer::DataInfoTuple Serializer::deserializeInfo(uint8_t *buffer) +{ + if (!buffer) + return {}; + + uint8_t *b = buffer; + unsigned int id = *reinterpret_cast(b); + DataType type = *reinterpret_cast((INFO_BLOB_TYPE(b))); + size_t size = *reinterpret_cast(INFO_BLOB_SIZE(b)); + + b = INFO_BLOB_DATA(b); + return std::make_tuple( + std::forward(id), loadInfo(type, b), + std::forward(size + INFO_BLOB_DATA_OFFS)); +} + +/** + * \brief Calculate the size of the data value once serialized to binary form + * + * Calculate the data value size in bytes comprising header, data and padding + * bytes to guarantee alignement to 64 bits boundary. + * + * The returned size is the actual byte size occupied by the data blob once + * serialized to a memory buffer. + * + * \return The blob size in bytes, aligned to Serializer::BLOB_ALIGN_BYTES + * boundary + */ +unsigned int Serializer::size(const DataValue &value) +{ + return VALUE_BLOB_DATA_OFFS + BLOB_ALIGN(value.size()); +} + +/** + * \brief Calculate the size of the data info once serialized to binary form + * + * Calculate the data info size in bytes comprising header, data and padding + * bytes to guarantee alignement to 64 bits boundary. + * + * The returned size is the actual byte size occupied by the data blob once + * serialized to a memory buffer. + * + * \return The blob size in bytes, aligned to Serializer::BLOB_ALIGN_BYTES + * boundary + */ +unsigned int Serializer::size(const DataInfo &info) +{ + /* + * Header is aligned as well as the transported data + * + * \todo If any non-DataValue field is added to DataInfo, the + * total size of the serialized package should be aligned with the + * ALIGN() macro. + */ + DataType type = info.min().type(); + return INFO_BLOB_DATA_OFFS + BLOB_ALIGN(DataSize[type]) + + BLOB_ALIGN(DataSize[type]); +} + +unsigned int Serializer::dumpValue(const DataValue &value, DataType type, + uint8_t *b) +{ + switch (type) { + case DataTypeBool: + *reinterpret_cast(b) = value.getBool(); + break; + case DataTypeInteger: + *reinterpret_cast(b) = value.getInt(); + break; + case DataTypeInteger64: + *reinterpret_cast(b) = value.getInt64(); + break; + default: + *b = 0; + break; + } + + return DataSize[type]; +} + +DataValue Serializer::loadValue(DataType type, uint8_t *b) +{ + switch (type) { + case DataTypeBool: + return DataValue(*reinterpret_cast(b)); + case DataTypeInteger: + return DataValue(*reinterpret_cast(b)); + case DataTypeInteger64: + return DataValue(*reinterpret_cast(b)); + default: + return DataValue(); + } +} + +DataInfo Serializer::loadInfo(DataType type, uint8_t *b) +{ + return DataInfo(loadValue(type, b), + loadValue(type, b + BLOB_ALIGN(DataSize[type]))); +} + +} /* namespace libcamera */