/*static*/
int GCAlloc::ConservativeGetMark(const void *item, bool bogusPointerReturnValue)
{
GCBlock *block = GetBlock(item);
#ifdef MMGC_MEMORY_INFO
item = GetRealPointer(item);
#endif
// guard against bogus pointers to the block header
if (item < block->items)
return bogusPointerReturnValue;
// floor value to start of item
// FIXME: do this w/o division if we can
int itemNum = GetIndex(block, item);
// skip pointers into dead space at end of block
if (itemNum > block->alloc->m_itemsPerBlock - 1)
return bogusPointerReturnValue;
// skip pointers into objects
if(block->items + itemNum * block->size != item)
return bogusPointerReturnValue;
return GetMark(item);
}
/* static */
bool GCLargeAlloc::ConservativeGetMark(const void *item, bool bogusPointerReturnValue)
{
if(((uintptr) item & 0xfff) == sizeof(LargeBlock))
{
return GetMark(item);
}
return bogusPointerReturnValue;
}
bool SQLTranslator::Translate(std::string& sql, std::string* pError)
{
size_t pos = 0;
size_t mark_size = 0;
std::string mark;
std::string mark_val;
while ( GetMark(sql, mark, pos) )
{
// 整个 $(...) 的大小
mark_size = mark.size() + 3;
if ( mark.find('+') != std::string::npos ) // 含 + 运算
{
if ( !CalcMark(mark, true, mark_val, pError) )
{
return false;
}
}
else if ( mark.find('-') != std::string::npos ) // 含 - 运算
{
if ( !CalcMark(mark, false, mark_val, pError) )
{
return false;
}
}
else // 不含 + 或者 - 运算
{
if ( !TransMark(mark, mark_val, pError) )
{
return false;
}
}
sql.replace(pos, mark_size, mark_val);
}
return true;
}