1 | #include <IO/HashingWriteBuffer.h> |
---|---|
2 | #include <iomanip> |
3 | |
4 | |
5 | namespace DB |
6 | { |
7 | |
8 | /// computation of the hash depends on the partitioning of blocks |
9 | /// so you need to compute a hash of n complete pieces and one incomplete |
10 | template <typename Buffer> |
11 | void IHashingBuffer<Buffer>::calculateHash(DB::BufferBase::Position data, size_t len) |
12 | { |
13 | if (len) |
14 | { |
15 | /// if the data is less than `block_size`, then put them into buffer and calculate hash later |
16 | if (block_pos + len < block_size) |
17 | { |
18 | memcpy(&BufferWithOwnMemory<Buffer>::memory[block_pos], data, len); |
19 | block_pos += len; |
20 | } |
21 | else |
22 | { |
23 | /// if something is already written to the buffer, then we'll add it |
24 | if (block_pos) |
25 | { |
26 | size_t n = block_size - block_pos; |
27 | memcpy(&BufferWithOwnMemory<Buffer>::memory[block_pos], data, n); |
28 | append(&BufferWithOwnMemory<Buffer>::memory[0]); |
29 | len -= n; |
30 | data += n; |
31 | block_pos = 0; |
32 | } |
33 | |
34 | while (len >= block_size) |
35 | { |
36 | append(data); |
37 | len -= block_size; |
38 | data += block_size; |
39 | } |
40 | |
41 | /// write the remainder to its buffer |
42 | if (len) |
43 | { |
44 | memcpy(&BufferWithOwnMemory<Buffer>::memory[0], data, len); |
45 | block_pos = len; |
46 | } |
47 | } |
48 | } |
49 | } |
50 | |
51 | template class IHashingBuffer<DB::ReadBuffer>; |
52 | template class IHashingBuffer<DB::WriteBuffer>; |
53 | |
54 | } |
55 |