: blockSize_(blockSize)
, allocChunk_(0)
, deallocChunk_(0)
{
assert(blockSize_ > 0);
prev_ = next_ = this;
std::size_t numBlocks = DEFAULT_CHUNK_SIZE / blockSize;
if (numBlocks > UCHAR_MAX) numBlocks = UCHAR_MAX;
else if (numBlocks == 0) numBlocks = 8 * blockSize;
//when numBlocks equals zero,the assert statement
// "assert(numBlocks_ == numBlocks);" always fails
numBlocks_ = static_cast<unsigned char>(numBlocks);
assert(numBlocks_ == numBlocks);
}
如注释所所示，当参数blockSize>DEFAULT_CHUNK_SIZE时，最后一条断言始终失败,
