From: ThorstenB Date: Sat, 10 Nov 2012 09:44:19 +0000 (+0100) Subject: gz wrapper to write and read "container files". X-Git-Url: https://git.mxchange.org/?a=commitdiff_plain;h=a9b45967ce43806ddd1df9f28860d6af0e51f39a;p=simgear.git gz wrapper to write and read "container files". Packs arbitrary data (strings, property trees, binary blobs, ...) into a single file. Use this for storing/loading user-data only, not for distribution files (scenery, aircraft etc). --- diff --git a/simgear/misc/CMakeLists.txt b/simgear/misc/CMakeLists.txt index d07b6718..6743cf89 100644 --- a/simgear/misc/CMakeLists.txt +++ b/simgear/misc/CMakeLists.txt @@ -13,7 +13,7 @@ set(HEADERS tabbed_values.hxx texcoord.hxx zfstream.hxx - + gzcontainerfile.hxx ) set(SOURCES @@ -26,6 +26,7 @@ set(SOURCES tabbed_values.cxx texcoord.cxx zfstream.cxx + gzcontainerfile.cxx ) simgear_component(misc misc "${SOURCES}" "${HEADERS}") diff --git a/simgear/misc/gzcontainerfile.cxx b/simgear/misc/gzcontainerfile.cxx new file mode 100644 index 00000000..b10b5f74 --- /dev/null +++ b/simgear/misc/gzcontainerfile.cxx @@ -0,0 +1,260 @@ +// Written by Thorsten Brehm, started November 2012. +// +// Copyright (C) 2012 Thorsten Brehm, brehmt at gmail dt com +// +// This library is free software; you can redistribute it and/or +// modify it under the terms of the GNU Library General Public +// License as published by the Free Software Foundation; either +// version 2 of the License, or (at your option) any later version. +// +// This library is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +// Library General Public License for more details. +// +// You should have received a copy of the GNU General Public License +// along with this program; if not, write to the Free Software +// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. +// +// $Id$ + +/** + * GZ Container File Format + * + * A (gzipped) binary file. + * + * Byte-order is little endian (we're ignoring big endian machines - for now..., + * - still usable, but they are writing an incompatible format). + * + * The binary file may contain an arbitrary number of containers. + * + * Each container has three elements: + * - container type + * - container payload size + * - container payload data (of given "size" in bytes) + * + * A container may consist of strings, property trees, raw binary data, and whatever else + * is implemented. + * + * Use this for storing/loading user-data only - not for distribution files (scenery, aircraft etc). + */ + +#ifdef HAVE_CONFIG_H +# include +#endif + +#include "gzcontainerfile.hxx" + +#include +#include + +#include + +using namespace std; +using namespace simgear; + +#if 1 + #define MY_SG_DEBUG SG_DEBUG +#else + #define MY_SG_DEBUG SG_ALERT +#endif + +/** The header is always the first container in each file, so it's ID doesn't + * really matter (as long as it isn't changed) - it cannot conflict with user-specific types. */ +const ContainerType HeaderType = 0; + +/** Magic word to detect big/little-endian file formats */ +static const uint32_t EndianMagic = 0x11223344; + +/************************************************************************** + * gzContainerWriter + **************************************************************************/ + +gzContainerWriter::gzContainerWriter(const std::string& name, + const std::string& fileMagic) : + sg_gzofstream(name, ios_out | ios_binary), + filename(name) +{ + /* write byte-order marker **************************************/ + write((char*)&EndianMagic, sizeof(EndianMagic)); + + /* write file header ********************************************/ + writeContainer(HeaderType, fileMagic.c_str()); +} + +/** Write the header of a single container. */ +bool +gzContainerWriter::writeContainerHeader(ContainerType Type, size_t Size) +{ + uint32_t ui32Data; + uint64_t ui64Data; + + SG_LOG(SG_IO, MY_SG_DEBUG, "Writing container " << Type << ", size " << Size); + + // write container type + ui32Data = Type; + write((char*)&ui32Data, sizeof(ui32Data)); + if (fail()) + return false; + + // write container payload size + ui64Data = Size; + write((char*)&ui64Data, sizeof(ui64Data)); + return !fail(); +} + +/** Write a complete container. */ +bool +gzContainerWriter::writeContainer(ContainerType Type, const char* pData, size_t Size) +{ + // write container type and size + if (!writeContainerHeader(Type, Size)) + return false; + + // write container payload + write(pData, Size); + return !fail(); +} + + +/** Save a single string in a separate container */ +bool +gzContainerWriter::writeContainer(ContainerType Type, const char* stringBuffer) +{ + return writeContainer(Type, stringBuffer, strlen(stringBuffer)+1); +} + +/** Save a property tree in a separate container */ +bool +gzContainerWriter::writeContainer(ContainerType Type, SGPropertyNode* root) +{ + stringstream oss; + writeProperties(oss, root, true); + return writeContainer(Type, oss.str().c_str()); +} + +/************************************************************************** + * gzContainerReader + **************************************************************************/ + +gzContainerReader::gzContainerReader(const std::string& name, + const std::string& fileMagic) : + sg_gzifstream(name, ios_in | ios_binary), + filename(name) +{ + bool ok = (good() && !eof()); + + /* check byte-order marker **************************************/ + if (ok) + { + uint32_t EndianCheck; + read((char*)&EndianCheck, sizeof(EndianCheck)); + if (eof() || !good()) + { + SG_LOG(SG_IO, SG_ALERT, "Error reading file " << name); + ok = false; + } + else + if (EndianCheck != EndianMagic) + { + SG_LOG(SG_IO, SG_ALERT, "Byte-order mismatch. This file was created for another architecture: " << filename); + ok = false; + } + } + + /* read file header *********************************************/ + if (ok) + { + char* FileHeader = NULL; + size_t Size = 0; + ContainerType Type = -1; + if (!readContainer(&Type, &FileHeader, &Size)) + { + SG_LOG(SG_IO, SG_ALERT, "File format not recognized. Missing file header: " << filename); + ok = false; + } + else + if ((HeaderType != Type)||(strcmp(FileHeader, fileMagic.c_str()))) + { + SG_LOG(SG_IO, MY_SG_DEBUG, "Invalid header. Container type " << Type << ", Header " << + ((FileHeader) ? FileHeader : "(none)")); + SG_LOG(SG_IO, SG_ALERT, "File not recognized. This is not a valid '" << fileMagic << "' file: " << filename); + ok = false; + } + + if (FileHeader) + { + free(FileHeader); + FileHeader = NULL; + } + } + + if (!ok) + { + setstate(badbit); + } +} + +/** Read the header of a single container. */ +bool +gzContainerReader::readContainerHeader(ContainerType* pType, size_t* pSize) +{ + uint32_t ui32Data; + uint64_t ui64Data; + + *pSize = 0; + *pType = -1; + + read((char*) &ui32Data, sizeof(ui32Data)); + if (eof()) + { + SG_LOG(SG_IO, SG_ALERT, "File corrupt? Unexpected end of file when reading container type in " << filename); + return false; + } + *pType = (ContainerType) ui32Data; + + read((char*) &ui64Data, sizeof(ui64Data)); + if (eof()) + { + SG_LOG(SG_IO, SG_ALERT, "File corrupt? Unexpected end of file when reading container size in " << filename); + return false; + } + *pSize = ui64Data; + + return !fail(); +} + +/** Read a single container and return its contents as a binary blob */ +bool +gzContainerReader::readContainer(ContainerType* pType, char** ppData, size_t* pSize) +{ + size_t Size = 0; + + *ppData = 0; + + if (!readContainerHeader(pType, &Size)) + { + SG_LOG(SG_IO, SG_ALERT, "Cannot load data. Invalid container header in " << filename); + return false; + } + + char* pData = (char*) malloc(Size); + if (!pData) + { + SG_LOG(SG_IO, SG_ALERT, "Cannot load data. No more memory when reading " << filename); + return false; + } + + read(pData, Size); + if (fail()) + { + SG_LOG(SG_IO, SG_ALERT, "File corrupt? Unexpected end of file when reading " << filename); + free(pData); + pData = 0; + return false; + } + + *ppData = pData; + *pSize = Size; + return true; +} diff --git a/simgear/misc/gzcontainerfile.hxx b/simgear/misc/gzcontainerfile.hxx new file mode 100644 index 00000000..bb30f69c --- /dev/null +++ b/simgear/misc/gzcontainerfile.hxx @@ -0,0 +1,64 @@ +// Written by Thorsten Brehm, started November 2012. +// +// Copyright (C) 2012 Thorsten Brehm, brehmt at gmail dt com +// +// This library is free software; you can redistribute it and/or +// modify it under the terms of the GNU Library General Public +// License as published by the Free Software Foundation; either +// version 2 of the License, or (at your option) any later version. +// +// This library is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +// Library General Public License for more details. +// +// You should have received a copy of the GNU General Public License +// along with this program; if not, write to the Free Software +// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. +// +// $Id$ + +#ifndef GZ_CONTAINER_FILE_HXX +#define GZ_CONTAINER_FILE_HXX + +#include +#include + +class SGPropertyNode; + +namespace simgear +{ + +typedef int ContainerType; + +/** A class to write container files. */ +class gzContainerReader : public sg_gzifstream +{ +public: + gzContainerReader( const std::string& name, + const std::string& fileMagic); + + bool readContainerHeader(ContainerType* pType, size_t* pSize); + bool readContainer(ContainerType* pType, char** ppData, size_t* pSize); +private: + std::string filename; +}; + +/** A class to read container files. */ +class gzContainerWriter : public sg_gzofstream +{ +public: + gzContainerWriter( const std::string& name, + const std::string& fileMagic); + + bool writeContainerHeader(ContainerType Type, size_t Size); + bool writeContainer(ContainerType Type, const char* pData, size_t Size); + bool writeContainer(ContainerType Type, const char* stringBuffer); + bool writeContainer(ContainerType Type, SGPropertyNode* root); +private: + std::string filename; +}; + +} + +#endif // GZ_CONTAINER_FILE_HXX