本文整理汇总了C++中IOStream::BytesLeftToRead方法的典型用法代码示例。如果您正苦于以下问题：C++ IOStream::BytesLeftToRead方法的具体用法？C++ IOStream::BytesLeftToRead怎么用？C++ IOStream::BytesLeftToRead使用的例子？那么, 这里精选的方法代码示例或许可以为您提供帮助。您也可以进一步了解该方法所在类IOStream的用法示例。
在下文中一共展示了IOStream::BytesLeftToRead方法的1个代码示例，这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞，您的评价将有助于系统推荐出更棒的C++代码示例。
示例1: MoveStreamPositionToBlockIndex
// --------------------------------------------------------------------------
//
// Function
// Name: BackupStoreFile::MoveStreamPositionToBlockIndex(IOStream &)
// Purpose: Move the file pointer in this stream to just before the block index.
// Assumes that the stream is at the beginning, seekable, and
// reading from the stream is OK.
// Created: 12/1/04
//
// --------------------------------------------------------------------------
void BackupStoreFile::MoveStreamPositionToBlockIndex(IOStream &rStream)
{
// Size of file
int64_t fileSize = rStream.BytesLeftToRead();
// Get header
file_StreamFormat hdr;
// Read the header
if(!rStream.ReadFullBuffer(&hdr, sizeof(hdr), 0 /* not interested in bytes read if this fails */, IOStream::TimeOutInfinite))
{
// Couldn't read header
THROW_EXCEPTION(BackupStoreException, CouldntReadEntireStructureFromStream)
}
// Check magic number
if(ntohl(hdr.mMagicValue) != OBJECTMAGIC_FILE_MAGIC_VALUE_V1
#ifndef BOX_DISABLE_BACKWARDS_COMPATIBILITY_BACKUPSTOREFILE
&& ntohl(hdr.mMagicValue) != OBJECTMAGIC_FILE_MAGIC_VALUE_V0
#endif
)
{
THROW_EXCEPTION(BackupStoreException, BadBackupStoreFile)
}
// Work out where the index is
int64_t numBlocks = box_ntoh64(hdr.mNumBlocks);
int64_t blockHeaderPosFromEnd = ((numBlocks * sizeof(file_BlockIndexEntry)) + sizeof(file_BlockIndexHeader));
// Sanity check
if(blockHeaderPosFromEnd > static_cast<int64_t>(fileSize - sizeof(file_StreamFormat)))
{
THROW_EXCEPTION(BackupStoreException, BadBackupStoreFile)
}
// Seek to that position
rStream.Seek(0 - blockHeaderPosFromEnd, IOStream::SeekType_End);
// Done. Stream now in right position (as long as the file is formatted correctly)
}