LCOV - code coverage report
Current view: top level - source/ps - FileIo.cpp (source / functions) Hit Total Coverage
Test: 0 A.D. test coverage report Lines: 31 71 43.7 %
Date: 2022-06-14 00:41:00 Functions: 6 12 50.0 %

          Line data    Source code
       1             : /* Copyright (C) 2019 Wildfire Games.
       2             :  * This file is part of 0 A.D.
       3             :  *
       4             :  * 0 A.D. is free software: you can redistribute it and/or modify
       5             :  * it under the terms of the GNU General Public License as published by
       6             :  * the Free Software Foundation, either version 2 of the License, or
       7             :  * (at your option) any later version.
       8             :  *
       9             :  * 0 A.D. is distributed in the hope that it will be useful,
      10             :  * but WITHOUT ANY WARRANTY; without even the implied warranty of
      11             :  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
      12             :  * GNU General Public License for more details.
      13             :  *
      14             :  * You should have received a copy of the GNU General Public License
      15             :  * along with 0 A.D.  If not, see <http://www.gnu.org/licenses/>.
      16             :  */
      17             : 
      18             : /*
      19             :  * endian-safe binary file IO helpers.
      20             :  */
      21             : 
      22             : #include "precompiled.h"
      23             : 
      24             : #include "FileIo.h"
      25             : #include "ps/CLogger.h"
      26             : #include "ps/CStr.h"
      27             : #include "ps/Filesystem.h"
      28             : #include "lib/byte_order.h"
      29             : 
      30             : #pragma pack(push, 1)
      31             : 
      32             : struct FileHeader
      33             : {
      34             :     char magic[4];
      35             :     u32 version_le;
      36             :     u32 payloadSize_le; // = file size - sizeof(FileHeader)
      37             : };
      38             : cassert(sizeof(FileHeader) == 12);
      39             : 
      40             : #pragma pack(pop)
      41             : 
      42             : 
      43             : //-----------------------------------------------------------------------------
      44             : // CFilePacker
      45             : 
      46           0 : CFilePacker::CFilePacker(u32 version, const char magic[4])
      47             : {
      48             :     // put header in our data array.
      49             :     // (its payloadSize_le will be updated on every Pack*() call)
      50           0 :     FileHeader header;
      51           0 :     std::copy(magic, magic + 4, header.magic);
      52           0 :     write_le32(&header.version_le, version);
      53           0 :     write_le32(&header.payloadSize_le, 0);
      54           0 :     m_writeBuffer.Append(&header, sizeof(FileHeader));
      55           0 : }
      56             : 
      57             : 
      58           0 : CFilePacker::~CFilePacker()
      59             : {
      60           0 : }
      61             : 
      62             : 
      63           0 : void CFilePacker::Write(const VfsPath& filename)
      64             : {
      65           0 :     const size_t payloadSize = m_writeBuffer.Size() - sizeof(FileHeader);
      66           0 :     const u32 payloadSize_le = to_le32(u32_from_larger(payloadSize));
      67           0 :     m_writeBuffer.Overwrite(&payloadSize_le, sizeof(payloadSize_le), 0+offsetof(FileHeader, payloadSize_le));
      68             : 
      69             :     // write out all data (including header)
      70           0 :     const Status st = g_VFS->CreateFile(filename, m_writeBuffer.Data(), m_writeBuffer.Size());
      71           0 :     if (st < 0)
      72             :     {
      73           0 :         LOGERROR("Failed to write file '%s' with status '%lld'", filename.string8(), (long long)st);
      74           0 :         throw PSERROR_File_WriteFailed();
      75             :     }
      76           0 : }
      77             : 
      78             : 
      79           0 : void CFilePacker::PackRaw(const void* rawData, size_t rawSize)
      80             : {
      81           0 :     m_writeBuffer.Append(rawData, rawSize);
      82           0 : }
      83             : 
      84           0 : void CFilePacker::PackSize(size_t value)
      85             : {
      86           0 :     const u32 value_le32 = to_le32(u32_from_larger(value));
      87           0 :     PackRaw(&value_le32, sizeof(value_le32));
      88           0 : }
      89             : 
      90           0 : void CFilePacker::PackString(const CStr& str)
      91             : {
      92           0 :     const size_t length = str.length();
      93           0 :     PackSize(length);
      94           0 :     PackRaw(str.c_str(), length);
      95           0 : }
      96             : 
      97             : 
      98             : //-----------------------------------------------------------------------------
      99             : // CFileUnpacker
     100             : 
     101           6 : CFileUnpacker::CFileUnpacker()
     102          12 :     : m_bufSize(0), m_unpackPos(0), m_version(0)
     103             : {
     104           6 : }
     105             : 
     106             : 
     107           6 : CFileUnpacker::~CFileUnpacker()
     108             : {
     109           6 : }
     110             : 
     111             : 
     112           6 : void CFileUnpacker::Read(const VfsPath& filename, const char magic[4])
     113             : {
     114             :     // if the file doesn't exist, LoadFile would raise an annoying error dialog.
     115             :     // since this (unfortunately) happens so often, we perform a separate
     116             :     // check and "just" raise an exception for the caller to handle.
     117             :     // (this is nicer than somehow squelching internal VFS error reporting)
     118           6 :     if(!VfsFileExists(filename))
     119           0 :         throw PSERROR_File_OpenFailed();
     120             : 
     121             :     // load the whole thing into memory
     122          12 :     if(g_VFS->LoadFile(filename, m_buf, m_bufSize) < 0)
     123           0 :         throw PSERROR_File_OpenFailed();
     124             : 
     125             :     // make sure we read enough for the header
     126           6 :     if(m_bufSize < sizeof(FileHeader))
     127             :     {
     128           0 :         m_buf.reset();
     129           0 :         m_bufSize = 0;
     130           0 :         throw PSERROR_File_ReadFailed();
     131             :     }
     132             : 
     133             :     // extract data from header
     134           6 :     FileHeader* header = (FileHeader*)m_buf.get();
     135           6 :     m_version = read_le32(&header->version_le);
     136           6 :     const size_t payloadSize = (size_t)read_le32(&header->payloadSize_le);
     137             : 
     138             :     // check we've got the right kind of file
     139             :     // .. and that we read exactly headerSize+payloadSize
     140           6 :     if(strncmp(header->magic, magic, 4) != 0 || m_bufSize != sizeof(FileHeader)+payloadSize)
     141             :     {
     142           0 :         m_buf.reset();
     143           0 :         m_bufSize = 0;
     144           0 :         throw PSERROR_File_InvalidType();
     145             :     }
     146             : 
     147           6 :     m_unpackPos = sizeof(FileHeader);
     148           6 : }
     149             : 
     150             : 
     151        3029 : void CFileUnpacker::UnpackRaw(void* rawData, size_t rawDataSize)
     152             : {
     153             :     // fail if reading past end of stream
     154        3029 :     if (m_unpackPos+rawDataSize > m_bufSize)
     155           0 :         throw PSERROR_File_UnexpectedEOF();
     156             : 
     157        3029 :     void* src = m_buf.get() + m_unpackPos;
     158        3029 :     memcpy(rawData, src, rawDataSize);
     159        3029 :     m_unpackPos += rawDataSize;
     160        3029 : }
     161             : 
     162             : 
     163          27 : size_t CFileUnpacker::UnpackSize()
     164             : {
     165          30 :     u32 value_le32;
     166          27 :     UnpackRaw(&value_le32, sizeof(value_le32));
     167          30 :     return (size_t)to_le32(value_le32);
     168             : }
     169             : 
     170             : 
     171           3 : void CFileUnpacker::UnpackString(CStr8& result)
     172             : {
     173           3 :     const size_t length = UnpackSize();
     174             : 
     175             :     // fail if reading past end of stream
     176           3 :     if (m_unpackPos+length > m_bufSize)
     177           0 :         throw PSERROR_File_UnexpectedEOF();
     178             : 
     179           3 :     result = CStr((char*)m_buf.get()+m_unpackPos, length);
     180           3 :     m_unpackPos += length;
     181           3 : }

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