本文整理汇总了C++中Offsets::back方法的典型用法代码示例。如果您正苦于以下问题：C++ Offsets::back方法的具体用法？C++ Offsets::back怎么用？C++ Offsets::back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Offsets的用法示例。
在下文中一共展示了Offsets::back方法的4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: replicateNumber
ColumnPtr ColumnArray::replicateNumber(const Offsets & replicate_offsets) const
{
size_t col_size = size();
if (col_size != replicate_offsets.size())
throw Exception("Size of offsets doesn't match size of column.", ErrorCodes::SIZES_OF_COLUMNS_DOESNT_MATCH);
MutableColumnPtr res = cloneEmpty();
if (0 == col_size)
return res;
ColumnArray & res_ = typeid_cast<ColumnArray &>(*res);
const typename ColumnVector<T>::Container & src_data = typeid_cast<const ColumnVector<T> &>(*data).getData();
const Offsets & src_offsets = getOffsets();
typename ColumnVector<T>::Container & res_data = typeid_cast<ColumnVector<T> &>(res_.getData()).getData();
Offsets & res_offsets = res_.getOffsets();
res_data.reserve(data->size() / col_size * replicate_offsets.back());
res_offsets.reserve(replicate_offsets.back());
Offset prev_replicate_offset = 0;
Offset prev_data_offset = 0;
Offset current_new_offset = 0;
for (size_t i = 0; i < col_size; ++i)
{
size_t size_to_replicate = replicate_offsets[i] - prev_replicate_offset;
size_t value_size = src_offsets[i] - prev_data_offset;
for (size_t j = 0; j < size_to_replicate; ++j)
{
current_new_offset += value_size;
res_offsets.push_back(current_new_offset);
if (value_size)
{
res_data.resize(res_data.size() + value_size);
memcpy(&res_data[res_data.size() - value_size], &src_data[prev_data_offset], value_size * sizeof(T));
}
}
prev_replicate_offset = replicate_offsets[i];
prev_data_offset = src_offsets[i];
}
return res;
}示例2: replicate
ColumnPtr ColumnFixedString::replicate(const Offsets & offsets) const
{
size_t col_size = size();
if (col_size != offsets.size())
throw Exception("Size of offsets doesn't match size of column.", ErrorCodes::SIZES_OF_COLUMNS_DOESNT_MATCH);
auto res = ColumnFixedString::create(n);
if (0 == col_size)
return std::move(res);
Chars_t & res_chars = res->chars;
res_chars.resize(n * offsets.back());
Offset curr_offset = 0;
for (size_t i = 0; i < col_size; ++i)
for (size_t next_offset = offsets[i]; curr_offset < next_offset; ++curr_offset)
memcpySmallAllowReadWriteOverflow15(&res->chars[curr_offset * n], &chars[i * n], n);
return std::move(res);
}示例3: replicateConst
ColumnPtr ColumnArray::replicateConst(const Offsets & replicate_offsets) const
{
size_t col_size = size();
if (col_size != replicate_offsets.size())
throw Exception("Size of offsets doesn't match size of column.", ErrorCodes::SIZES_OF_COLUMNS_DOESNT_MATCH);
if (0 == col_size)
return cloneEmpty();
const Offsets & src_offsets = getOffsets();
auto res_column_offsets = ColumnOffsets::create();
Offsets & res_offsets = res_column_offsets->getData();
res_offsets.reserve(replicate_offsets.back());
Offset prev_replicate_offset = 0;
Offset prev_data_offset = 0;
Offset current_new_offset = 0;
for (size_t i = 0; i < col_size; ++i)
{
size_t size_to_replicate = replicate_offsets[i] - prev_replicate_offset;
size_t value_size = src_offsets[i] - prev_data_offset;
for (size_t j = 0; j < size_to_replicate; ++j)
{
current_new_offset += value_size;
res_offsets.push_back(current_new_offset);
}
prev_replicate_offset = replicate_offsets[i];
prev_data_offset = src_offsets[i];
}
return ColumnArray::create(getData().cloneResized(current_new_offset), std::move(res_column_offsets));
}示例4: replicateString
ColumnPtr ColumnArray::replicateString(const Offsets & replicate_offsets) const
{
size_t col_size = size();
if (col_size != replicate_offsets.size())
throw Exception("Size of offsets doesn't match size of column.", ErrorCodes::SIZES_OF_COLUMNS_DOESNT_MATCH);
MutableColumnPtr res = cloneEmpty();
if (0 == col_size)
return res;
ColumnArray & res_ = static_cast<ColumnArray &>(*res);
const ColumnString & src_string = typeid_cast<const ColumnString &>(*data);
const ColumnString::Chars & src_chars = src_string.getChars();
const Offsets & src_string_offsets = src_string.getOffsets();
const Offsets & src_offsets = getOffsets();
ColumnString::Chars & res_chars = typeid_cast<ColumnString &>(res_.getData()).getChars();
Offsets & res_string_offsets = typeid_cast<ColumnString &>(res_.getData()).getOffsets();
Offsets & res_offsets = res_.getOffsets();
res_chars.reserve(src_chars.size() / col_size * replicate_offsets.back());
res_string_offsets.reserve(src_string_offsets.size() / col_size * replicate_offsets.back());
res_offsets.reserve(replicate_offsets.back());
Offset prev_replicate_offset = 0;
Offset prev_src_offset = 0;
Offset prev_src_string_offset = 0;
Offset current_res_offset = 0;
Offset current_res_string_offset = 0;
for (size_t i = 0; i < col_size; ++i)
{
/// How much to replicate the array.
size_t size_to_replicate = replicate_offsets[i] - prev_replicate_offset;
/// The number of rows in the array.
size_t value_size = src_offsets[i] - prev_src_offset;
/// Number of characters in rows of the array, including zero/null bytes.
size_t sum_chars_size = value_size == 0 ? 0 : (src_string_offsets[prev_src_offset + value_size - 1] - prev_src_string_offset);
for (size_t j = 0; j < size_to_replicate; ++j)
{
current_res_offset += value_size;
res_offsets.push_back(current_res_offset);
size_t prev_src_string_offset_local = prev_src_string_offset;
for (size_t k = 0; k < value_size; ++k)
{
/// Size of one row.
size_t chars_size = src_string_offsets[k + prev_src_offset] - prev_src_string_offset_local;
current_res_string_offset += chars_size;
res_string_offsets.push_back(current_res_string_offset);
prev_src_string_offset_local += chars_size;
}
if (sum_chars_size)
{
/// Copies the characters of the array of rows.
res_chars.resize(res_chars.size() + sum_chars_size);
memcpySmallAllowReadWriteOverflow15(
&res_chars[res_chars.size() - sum_chars_size], &src_chars[prev_src_string_offset], sum_chars_size);
}
}
prev_replicate_offset = replicate_offsets[i];
prev_src_offset = src_offsets[i];
prev_src_string_offset += sum_chars_size;
}
return res;
}