forked from 0ad/0ad
106 lines
2.7 KiB
C++
Executable File
106 lines
2.7 KiB
C++
Executable File
///////////////////////////////////////////////////////////////////////////////
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//
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// Name: FileUnpacker.cpp
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// Author: Rich Cross
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// Contact: rich@wildfiregames.com
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//
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///////////////////////////////////////////////////////////////////////////////
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#include "precompiled.h"
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#include "FileUnpacker.h"
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#include "res/vfs.h"
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////////////////////////////////////////////////////////////////////////////////////////
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// CFileUnpacker constructor
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CFileUnpacker::CFileUnpacker()
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{
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m_Buf = 0;
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m_Size = 0;
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m_UnpackPos = 0;
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m_Version = 0;
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}
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////////////////////////////////////////////////////////////////////////////////////////
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// Read: open and read in given file, check magic bits against those given; throw
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// variety of exceptions for missing files etc
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void CFileUnpacker::Read(const char* filename,const char magicstr[4])
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{
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// load the whole thing into memory
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Handle hm = vfs_load(filename, m_Buf, m_Size);
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if(hm <= 0)
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{
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m_Buf = 0;
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m_Size = 0;
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throw CFileOpenError();
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}
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// make sure we read enough for the header
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if(m_Size < 12)
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{
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mem_free_h(hm);
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m_Buf = 0;
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m_Size = 0;
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throw CFileReadError();
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}
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// extract data from header
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u8* header = (u8*)m_Buf;
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char* magic = (char*)(header+0);
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// FIXME m_Version and datasize: Byte order? -- Simon
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m_Version = *(u32*)(header+4);
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u32 datasize = *(u32*)(header+8);
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// check we've got the right kind of file
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// .. and that we read exactly headersize+datasize
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if(strncmp(magic, magicstr, 4) != 0 ||
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m_Size != 12+datasize)
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{
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mem_free_h(hm);
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m_Buf = 0;
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m_Size = 0;
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throw CFileTypeError();
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}
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m_UnpackPos = 12;
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}
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////////////////////////////////////////////////////////////////////////////////////////
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// UnpackRaw: unpack given number of bytes from the input stream into the given array
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// - throws CFileEOFError if the end of the data stream is reached before the given
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// number of bytes have been read
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void CFileUnpacker::UnpackRaw(void* rawdata,u32 rawdatalen)
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{
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// got enough data to unpack?
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if (m_UnpackPos+rawdatalen<=m_Size)
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{
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// yes .. copy over
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void* src = (char*)m_Buf + m_UnpackPos;
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memcpy(rawdata, src, rawdatalen);
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m_UnpackPos += rawdatalen;
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}
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else
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// nope - throw exception
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throw CFileEOFError();
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}
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////////////////////////////////////////////////////////////////////////////////////////
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// UnpackString: unpack a string from the raw data stream
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// - throws CFileEOFError if eof is reached before the string length has been
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// satisfied
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void CFileUnpacker::UnpackString(CStr& result)
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{
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// get string length
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u32 length;
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UnpackRaw(&length,sizeof(length)); // FIXME Byte order? -- Simon
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if (m_UnpackPos + length <= m_Size)
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{
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result=std::string((char *)m_Buf+m_UnpackPos, length);
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m_UnpackPos += length;
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}
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else
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throw CFileEOFError();
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}
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