diff options
Diffstat (limited to 'src/lib')
| -rw-r--r-- | src/lib/stream/ctr/ctr.cpp | 24 |
1 files changed, 19 insertions, 5 deletions
diff --git a/src/lib/stream/ctr/ctr.cpp b/src/lib/stream/ctr/ctr.cpp index 6a7d81729..3608eedf9 100644 --- a/src/lib/stream/ctr/ctr.cpp +++ b/src/lib/stream/ctr/ctr.cpp @@ -205,13 +205,27 @@ void CTR_BE::seek(uint64_t offset) const size_t BS = m_block_size; // Set m_counter blocks to IV, IV + 1, ... IV + n - for(size_t i = 1; i != m_ctr_blocks; ++i) + + if(m_ctr_size == 4 && BS >= 8) + { + const uint32_t low32 = load_be<uint32_t>(&m_counter[BS-4], 0); + for(size_t i = 1; i != m_ctr_blocks; ++i) + { + copy_mem(&m_counter[i*BS], &m_counter[0], BS); + uint32_t c = low32 + i; + store_be(c, &m_counter[(BS-4)+i*BS]); + } + } + else { - buffer_insert(m_counter, i*BS, &m_counter[(i-1)*BS], BS); + for(size_t i = 1; i != m_ctr_blocks; ++i) + { + buffer_insert(m_counter, i*BS, &m_counter[(i-1)*BS], BS); - for(size_t j = 0; j != m_ctr_size; ++j) - if(++m_counter[i*BS + (BS - 1 - j)]) - break; + for(size_t j = 0; j != m_ctr_size; ++j) + if(++m_counter[i*BS + (BS - 1 - j)]) + break; + } } if(base_counter > 0) |