1
0
forked from 0ad/0ad
0ad/source/ps/FileUnpacker.cpp

124 lines
3.5 KiB
C++

///////////////////////////////////////////////////////////////////////////////
//
// Name: FileUnpacker.cpp
// Author: Rich Cross
// Contact: rich@wildfiregames.com
//
///////////////////////////////////////////////////////////////////////////////
#include "precompiled.h"
#include "FileUnpacker.h"
#include "lib/path_util.h"
#include "lib/res/res.h"
////////////////////////////////////////////////////////////////////////////////////////
// CFileUnpacker constructor
CFileUnpacker::CFileUnpacker()
{
m_Buf = 0;
m_Size = 0;
m_UnpackPos = 0;
m_Version = 0;
}
CFileUnpacker::~CFileUnpacker()
{
file_buf_free(m_Buf);
}
////////////////////////////////////////////////////////////////////////////////////////
// Read: open and read in given file, check magic bits against those given; throw
// variety of exceptions for missing files etc
void CFileUnpacker::Read(const char* filename,const char magicstr[4])
{
// avoid vfs_load complaining about missing data files (which happens
// too often). better to check here than squelch internal VFS error
// reporting. we disable this in release mode to avoid a speed hit.
// UPDATE: We don't disable this in release mode, because vfs_load now
// complains about missing files when running in release
//#ifndef NDEBUG
if(!vfs_exists(filename))
throw PSERROR_File_OpenFailed();
//#endif
// somewhat of a hack: if loading a map (.PMP), tell the file manager
// that the buffer will be kept in memory longer (avoids warning).
uint flags = 0;
const char* ext = path_extension(filename);
if(!stricmp(ext, "pmp"))
flags |= FILE_LONG_LIVED;
// load the whole thing into memory
if(vfs_load(filename, m_Buf, m_Size, flags) < 0)
throw PSERROR_File_OpenFailed();
// make sure we read enough for the header
if(m_Size < 12)
{
(void)file_buf_free(m_Buf);
m_Buf = 0;
m_Size = 0;
throw PSERROR_File_ReadFailed();
}
// extract data from header
u8* header = (u8*)m_Buf;
char* magic = (char*)(header+0);
// FIXME m_Version and datasize: Byte order? -- Simon
m_Version = *(u32*)(header+4);
u32 datasize = *(u32*)(header+8);
// check we've got the right kind of file
// .. and that we read exactly headersize+datasize
if(strncmp(magic, magicstr, 4) != 0 ||
m_Size != 12+datasize)
{
(void)file_buf_free(m_Buf);
m_Buf = 0;
m_Size = 0;
throw PSERROR_File_InvalidType();
}
m_UnpackPos = 12;
}
////////////////////////////////////////////////////////////////////////////////////////
// UnpackRaw: unpack given number of bytes from the input stream into the given array
// - throws CFileEOFError if the end of the data stream is reached before the given
// number of bytes have been read
void CFileUnpacker::UnpackRaw(void* rawdata,u32 rawdatalen)
{
// got enough data to unpack?
if (m_UnpackPos+rawdatalen<=m_Size)
{
// yes .. copy over
void* src = (char*)m_Buf + m_UnpackPos;
memcpy2(rawdata, src, rawdatalen);
m_UnpackPos += rawdatalen;
}
else
// nope - throw exception
throw PSERROR_File_UnexpectedEOF();
}
////////////////////////////////////////////////////////////////////////////////////////
// UnpackString: unpack a string from the raw data stream
// - throws CFileEOFError if eof is reached before the string length has been
// satisfied
void CFileUnpacker::UnpackString(CStr& result)
{
// get string length
u32 length;
UnpackRaw(&length,sizeof(length)); // FIXME Byte order? -- Simon
if (m_UnpackPos + length <= m_Size)
{
result=std::string((char *)m_Buf+m_UnpackPos, length);
m_UnpackPos += length;
}
else
throw PSERROR_File_UnexpectedEOF();
}