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/* Copyright (C) 2013 Wildfire Games.
* This file is part of 0 A.D.
*
* 0 A.D. is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 2 of the License, or
* (at your option) any later version.
*
* 0 A.D. 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with 0 A.D. If not, see <http://www.gnu.org/licenses/>.
*/
/*
* endian-safe binary file IO helpers.
*/
#include "precompiled.h"
#include "FileIo.h"
#include "ps/CLogger.h"
#include "ps/Filesystem.h"
#include "lib/byte_order.h"
#pragma pack(push, 1)
struct FileHeader
{
char magic[4];
u32 version_le;
u32 payloadSize_le; // = file size - sizeof(FileHeader)
};
cassert(sizeof(FileHeader) == 12);
#pragma pack(pop)
//-----------------------------------------------------------------------------
// CFilePacker
CFilePacker::CFilePacker(u32 version, const char magic[4])
{
// put header in our data array.
// (its payloadSize_le will be updated on every Pack*() call)
FileHeader header;
strncpy(header.magic, magic, 4); // not 0-terminated => no _s
write_le32(&header.version_le, version);
write_le32(&header.payloadSize_le, 0);
m_writeBuffer.Append(&header, sizeof(FileHeader));
}
CFilePacker::~CFilePacker()
{
}
void CFilePacker::Write(const VfsPath& filename)
{
const size_t payloadSize = m_writeBuffer.Size() - sizeof(FileHeader);
const u32 payloadSize_le = to_le32(u32_from_larger(payloadSize));
m_writeBuffer.Overwrite(&payloadSize_le, sizeof(payloadSize_le), 0+offsetof(FileHeader, payloadSize_le));
// write out all data (including header)
const Status st = g_VFS->CreateFile(filename, m_writeBuffer.Data(), m_writeBuffer.Size());
if (st < 0)
{
LOGERROR("Failed to write file '%s' with status '%lld'", filename.string8(), (long long)st);
throw PSERROR_File_WriteFailed();
}
}
void CFilePacker::PackRaw(const void* rawData, size_t rawSize)
{
m_writeBuffer.Append(rawData, rawSize);
}
void CFilePacker::PackSize(size_t value)
{
const u32 value_le32 = to_le32(u32_from_larger(value));
PackRaw(&value_le32, sizeof(value_le32));
}
void CFilePacker::PackString(const CStr& str)
{
const size_t length = str.length();
PackSize(length);
PackRaw(str.c_str(), length);
}
//-----------------------------------------------------------------------------
// CFileUnpacker
CFileUnpacker::CFileUnpacker()
: m_bufSize(0), m_unpackPos(0), m_version(0)
{
}
CFileUnpacker::~CFileUnpacker()
{
}
void CFileUnpacker::Read(const VfsPath& filename, const char magic[4])
{
// if the file doesn't exist, LoadFile would raise an annoying error dialog.
// since this (unfortunately) happens so often, we perform a separate
// check and "just" raise an exception for the caller to handle.
// (this is nicer than somehow squelching internal VFS error reporting)
if(!VfsFileExists(filename))
throw PSERROR_File_OpenFailed();
// load the whole thing into memory
if(g_VFS->LoadFile(filename, m_buf, m_bufSize) < 0)
throw PSERROR_File_OpenFailed();
// make sure we read enough for the header
if(m_bufSize < sizeof(FileHeader))
{
m_buf.reset();
m_bufSize = 0;
throw PSERROR_File_ReadFailed();
}
// extract data from header
FileHeader* header = (FileHeader*)m_buf.get();
m_version = read_le32(&header->version_le);
const size_t payloadSize = (size_t)read_le32(&header->payloadSize_le);
// check we've got the right kind of file
// .. and that we read exactly headerSize+payloadSize
if(strncmp(header->magic, magic, 4) != 0 || m_bufSize != sizeof(FileHeader)+payloadSize)
{
m_buf.reset();
m_bufSize = 0;
throw PSERROR_File_InvalidType();
}
m_unpackPos = sizeof(FileHeader);
}
void CFileUnpacker::UnpackRaw(void* rawData, size_t rawDataSize)
{
// fail if reading past end of stream
if (m_unpackPos+rawDataSize > m_bufSize)
throw PSERROR_File_UnexpectedEOF();
void* src = m_buf.get() + m_unpackPos;
memcpy(rawData, src, rawDataSize);
m_unpackPos += rawDataSize;
}
size_t CFileUnpacker::UnpackSize()
{
u32 value_le32;
UnpackRaw(&value_le32, sizeof(value_le32));
return (size_t)to_le32(value_le32);
}
void CFileUnpacker::UnpackString(CStr8& result)
{
const size_t length = UnpackSize();
// fail if reading past end of stream
if (m_unpackPos+length > m_bufSize)
throw PSERROR_File_UnexpectedEOF();
result = CStr((char*)m_buf.get()+m_unpackPos, length);
m_unpackPos += length;
}
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