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p7zip-rar/CPP/7zip/Compress/Lzham/lzhamcomp/lzham_match_accel.cpp

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Imported Upstream version 16.02
2017-10-11 12:40:22 +02:00
// File: lzham_match_accel.cpp
// See Copyright Notice and license at the end of include/lzham.h
#include "lzham_core.h"
#include "lzham_match_accel.h"
#include "lzham_timer.h"
static const int cHashSize24 = 0x1000000;
static const int cHashSize16 = 0x10000;
namespace lzham
{
static inline uint32 hash2_to_12(uint c0, uint c1) { return c0 ^ (c1 << 4); }
#define LZHAM_HASH3_16(c0, c1, c2) ((((uint)c0) | (((uint)c1) << 8U)) ^ (((uint)c2) << 4U))
#define LZHAM_HASH3_24(c0, c1, c2) (((uint)c0) | (((uint)c1) << 8U) | (((uint)c2) << 16U))
search_accelerator::search_accelerator(lzham_malloc_context malloc_context) :
m_malloc_context(malloc_context),
m_pLZBase(NULL),
m_pTask_pool(NULL),
m_max_helper_threads(0),
m_max_dict_size(0),
m_max_dict_size_mask(0),
m_lookahead_pos(0),
m_lookahead_size(0),
m_cur_dict_size(0),
m_dict(malloc_context),
m_hash(malloc_context),
m_nodes(malloc_context),
m_matches(malloc_context),
m_match_refs(malloc_context),
m_digram_hash(malloc_context),
m_digram_next(malloc_context),
m_fill_lookahead_pos(0),
m_fill_lookahead_size(0),
m_fill_dict_size(0),
m_max_probes(0),
m_max_matches(0),
m_all_matches(false),
m_deterministic(false),
m_len2_matches(false),
m_hash24(false),
m_next_match_ref(0),
m_num_completed_helper_threads(0)
{
for (uint i = 0; i < LZHAM_ARRAY_SIZE(m_thread_dict_offsets); i++)
m_thread_dict_offsets[i].set_malloc_context(malloc_context);
}
bool search_accelerator::init(CLZBase* pLZBase, task_pool* pPool, uint max_helper_threads, uint max_dict_size, uint max_matches, bool all_matches, uint max_probes, uint flags)
{
LZHAM_ASSERT(pLZBase);
LZHAM_ASSERT(max_dict_size && math::is_power_of_2(max_dict_size));
LZHAM_ASSERT(max_probes);
m_max_probes = LZHAM_MIN(cMatchAccelMaxSupportedProbes, max_probes);
m_deterministic = (flags & cFlagDeterministic) != 0;
m_len2_matches = (flags & cFlagLen2Matches) != 0;
m_hash24 = (flags & cFlagHash24) != 0;
m_pLZBase = pLZBase;
m_pTask_pool = max_helper_threads ? pPool : NULL;
m_max_helper_threads = m_pTask_pool ? max_helper_threads : 0;
m_max_matches = LZHAM_MIN(m_max_probes, max_matches);
m_all_matches = all_matches;
m_max_dict_size = max_dict_size;
m_max_dict_size_mask = m_max_dict_size - 1;
m_cur_dict_size = 0;
m_lookahead_size = 0;
m_lookahead_pos = 0;
m_fill_lookahead_pos = 0;
m_fill_lookahead_size = 0;
m_fill_dict_size = 0;
m_num_completed_helper_threads = 0;
if (!m_dict.try_resize_no_construct(max_dict_size + LZHAM_MIN(m_max_dict_size, static_cast<uint>(CLZBase::cMaxHugeMatchLen))))
{
LZHAM_LOG_ERROR(9000);
return false;
}
if (!m_hash.try_resize_no_construct(m_hash24 ? cHashSize24 : cHashSize16))
{
LZHAM_LOG_ERROR(9001);
return false;
}
memset(m_hash.get_ptr(), 0, m_hash.size_in_bytes());
if (!m_nodes.try_resize_no_construct(max_dict_size))
{
LZHAM_LOG_ERROR(9002);
return false;
}
for (uint i = 0; i < max_helper_threads; i++)
{
if (!m_thread_dict_offsets[i].try_reserve(256 * 1024))
{
LZHAM_LOG_ERROR(9003);
return false;
}
}
// Shouldn't be necessary
//if (m_deterministic)
// memset(m_nodes.get_ptr(), 0, m_nodes.size_in_bytes());
return true;
}
void search_accelerator::reset()
{
m_cur_dict_size = 0;
m_lookahead_size = 0;
m_lookahead_pos = 0;
m_fill_lookahead_pos = 0;
m_fill_lookahead_size = 0;
m_fill_dict_size = 0;
m_num_completed_helper_threads = 0;
// Clearing the hash tables is only necessary for determinism (otherwise, it's possible the matches returned after a reset will depend on the data processes before the reset).
if (m_hash.size())
memset(m_hash.get_ptr(), 0, m_hash.size_in_bytes());
if (m_digram_hash.size())
memset(m_digram_hash.get_ptr(), 0, m_digram_hash.size_in_bytes());
// Shouldn't be necessary
//if (m_deterministic)
// memset(m_nodes.get_ptr(), 0, m_nodes.size_in_bytes());
}
void search_accelerator::flush()
{
m_cur_dict_size = 0;
}
uint search_accelerator::get_max_add_bytes() const
{
uint add_pos = static_cast<uint>(m_lookahead_pos & (m_max_dict_size - 1));
return m_max_dict_size - add_pos;
}
static uint8 g_hamming_dist[256] =
{
0, 1, 1, 2, 1, 2, 2, 3, 1, 2, 2, 3, 2, 3, 3, 4,
1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
4, 5, 5, 6, 5, 6, 6, 7, 5, 6, 6, 7, 6, 7, 7, 8
};
void search_accelerator::find_all_matches_callback_st(uint64 data, void* pData_ptr)
{
scoped_perf_section find_all_matches_timer("find_all_matches_callback_st");
LZHAM_NOTE_UNUSED(data);
LZHAM_NOTE_UNUSED(pData_ptr);
dict_match temp_matches[cMatchAccelMaxSupportedProbes * 2];
uint fill_lookahead_pos = m_fill_lookahead_pos;
uint fill_dict_size = m_fill_dict_size;
uint fill_lookahead_size = m_fill_lookahead_size;
uint c0 = 0, c1 = 0;
if (fill_lookahead_size >= 2)
{
c0 = m_dict[fill_lookahead_pos & m_max_dict_size_mask];
c1 = m_dict[(fill_lookahead_pos & m_max_dict_size_mask) + 1];
}
const uint8* pDict = m_dict.get_ptr();
while (fill_lookahead_size >= 3)
{
uint insert_pos = fill_lookahead_pos & m_max_dict_size_mask;
uint c2 = pDict[insert_pos + 2];
uint h;
if (m_hash24)
h = LZHAM_HASH3_24(c0, c1, c2);
else
h = LZHAM_HASH3_16(c0, c1, c2);
c0 = c1;
c1 = c2;
dict_match *pDstMatch = temp_matches;
uint cur_pos = m_hash[h];
m_hash[h] = static_cast<uint>(fill_lookahead_pos);
uint *pLeft = &m_nodes[insert_pos].m_left;
uint *pRight = &m_nodes[insert_pos].m_right;
const uint max_match_len = LZHAM_MIN(static_cast<uint>(CLZBase::cMaxMatchLen), fill_lookahead_size);
uint best_match_len = 2;
const uint8* pIns = &pDict[insert_pos];
uint n = m_max_probes;
for ( ; ; )
{
uint delta_pos = fill_lookahead_pos - cur_pos;
if ((n-- == 0) || (!delta_pos) || (delta_pos >= fill_dict_size))
{
*pLeft = 0;
*pRight = 0;
break;
}
uint pos = cur_pos & m_max_dict_size_mask;
// Unfortunately, the initial compare match_len must be 0 because of the way we hash and truncate matches at the end of each block.
uint match_len = 0;
const uint8* pComp = &pDict[pos];
#if LZHAM_PLATFORM_X360 || (LZHAM_USE_UNALIGNED_INT_LOADS == 0) || LZHAM_BIG_ENDIAN_CPU
for ( ; match_len < max_match_len; match_len++)
if (pComp[match_len] != pIns[match_len])
break;
#else
// Compare a qword at a time for a bit more efficiency.
uint64 x = *reinterpret_cast<const uint64 *>(pComp);
uint64 y = *reinterpret_cast<const uint64 *>(pIns);
if ((max_match_len >= 8) && (x == y))
{
const uint64* pComp_cur = reinterpret_cast<const uint64*>(pComp) + 1;
const uint64* pIns_cur = reinterpret_cast<const uint64*>(pIns) + 1;
const uint64* pComp_end = reinterpret_cast<const uint64*>(pComp + max_match_len - 7);
while (pComp_cur < pComp_end)
{
if (*pComp_cur != *pIns_cur)
break;
++pComp_cur;
++pIns_cur;
}
uint alt_match_len = static_cast<uint>(reinterpret_cast<const uint8*>(pComp_cur) - reinterpret_cast<const uint8*>(pComp));
for ( ; alt_match_len < max_match_len; alt_match_len++)
if (pComp[alt_match_len] != pIns[alt_match_len])
break;
match_len = alt_match_len;
}
else
{
if ((uint32)x == (uint32)y)
{
x >>= 32;
y >>= 32;
match_len += 4;
}
if ((uint16)x == (uint16)y)
{
x >>= 16;
y >>= 16;
match_len += 2;
}
if ((uint8)x == (uint8)y)
match_len++;
match_len = math::minimum(match_len, max_match_len);
}
#endif
#ifdef LZVERIFY
uint check_match_len;
for (check_match_len = 0; check_match_len < max_match_len; check_match_len++)
if (pComp[check_match_len] != pIns[check_match_len])
break;
LZHAM_VERIFY(match_len == check_match_len);
#endif
node *pNode = &m_nodes[pos];
if (match_len > best_match_len)
{
pDstMatch->m_len = static_cast<uint16>(match_len - CLZBase::cMinMatchLen);
pDstMatch->m_dist = delta_pos;
pDstMatch++;
best_match_len = match_len;
if (match_len == max_match_len)
{
*pLeft = pNode->m_left;
*pRight = pNode->m_right;
break;
}
}
else if (m_all_matches)
{
pDstMatch->m_len = static_cast<uint16>(match_len - CLZBase::cMinMatchLen);
pDstMatch->m_dist = delta_pos;
pDstMatch++;
}
else if ((best_match_len > 2) && (best_match_len == match_len))
{
uint bestMatchDist = pDstMatch[-1].m_dist;
uint compMatchDist = delta_pos;
uint bestMatchSlot, bestMatchSlotOfs;
m_pLZBase->compute_lzx_position_slot(bestMatchDist, bestMatchSlot, bestMatchSlotOfs);
uint compMatchSlot, compMatchOfs;
m_pLZBase->compute_lzx_position_slot(compMatchDist, compMatchSlot, compMatchOfs);
// If both matches uses the same match slot, choose the one with the offset containing the lowest nibble as these bits separately entropy coded.
// This could choose a match which is further away in the absolute sense, but closer in a coding sense.
if ( (compMatchSlot < bestMatchSlot) ||
((compMatchSlot >= 8) && (compMatchSlot == bestMatchSlot) && ((compMatchOfs & 15) < (bestMatchSlotOfs & 15))) )
{
LZHAM_ASSERT((pDstMatch[-1].m_len + (uint)CLZBase::cMinMatchLen) == best_match_len);
pDstMatch[-1].m_dist = delta_pos;
}
else if ((match_len < max_match_len) && (compMatchSlot <= bestMatchSlot))
{
// Choose the match which has lowest hamming distance in the mismatch byte for a tiny win on binary files.
// TODO: This competes against the prev. optimization.
uint desired_mismatch_byte = pIns[match_len];
uint cur_mismatch_byte = pDict[(insert_pos - bestMatchDist + match_len) & m_max_dict_size_mask];
uint cur_mismatch_dist = g_hamming_dist[cur_mismatch_byte ^ desired_mismatch_byte];
uint new_mismatch_byte = pComp[match_len];
uint new_mismatch_dist = g_hamming_dist[new_mismatch_byte ^ desired_mismatch_byte];
if (new_mismatch_dist < cur_mismatch_dist)
{
LZHAM_ASSERT((pDstMatch[-1].m_len + (uint)CLZBase::cMinMatchLen) == best_match_len);
pDstMatch[-1].m_dist = delta_pos;
}
}
}
uint new_pos;
if (pComp[match_len] < pIns[match_len])
{
*pLeft = cur_pos;
pLeft = &pNode->m_right;
new_pos = pNode->m_right;
}
else
{
*pRight = cur_pos;
pRight = &pNode->m_left;
new_pos = pNode->m_left;
}
if (new_pos == cur_pos)
break;
cur_pos = new_pos;
}
const uint num_matches = (uint)(pDstMatch - temp_matches);
if (num_matches)
{
pDstMatch[-1].m_dist |= 0x80000000;
const uint num_matches_to_write = LZHAM_MIN(num_matches, m_max_matches);
const uint match_ref_ofs = m_next_match_ref;
m_next_match_ref += num_matches_to_write;
memcpy(&m_matches[match_ref_ofs],
temp_matches + (num_matches - num_matches_to_write),
sizeof(temp_matches[0]) * num_matches_to_write);
m_match_refs[static_cast<uint>(fill_lookahead_pos - m_fill_lookahead_pos)] = match_ref_ofs;
}
else
{
m_match_refs[static_cast<uint>(fill_lookahead_pos - m_fill_lookahead_pos)] = -2;
}
fill_lookahead_pos++;
fill_lookahead_size--;
fill_dict_size++;
}
while (fill_lookahead_size)
{
uint insert_pos = fill_lookahead_pos & m_max_dict_size_mask;
m_nodes[insert_pos].m_left = 0;
m_nodes[insert_pos].m_right = 0;
m_match_refs[static_cast<uint>(fill_lookahead_pos - m_fill_lookahead_pos)] = -2;
fill_lookahead_pos++;
fill_lookahead_size--;
fill_dict_size++;
}
m_num_completed_helper_threads++;
}
void search_accelerator::find_all_matches_callback_mt(uint64 data, void* pData_ptr)
{
scoped_perf_section find_all_matches_timer(cVarArgs, "find_all_matches_callback_mt %u", (uint)data);
LZHAM_NOTE_UNUSED(pData_ptr);
const uint thread_index = (uint)data;
dict_match temp_matches[cMatchAccelMaxSupportedProbes * 2];
const uint8* pDict = m_dict.get_ptr();
const uint *pDict_ofsets = m_thread_dict_offsets[thread_index].get_ptr();
const uint num_dict_offsets = m_thread_dict_offsets[thread_index].size();
for (uint i = 0; i < num_dict_offsets; i++)
{
uint lookahead_ofs = *pDict_ofsets++;
uint fill_lookahead_pos = m_fill_lookahead_pos + lookahead_ofs;
uint fill_dict_size = m_fill_dict_size + lookahead_ofs;
LZHAM_ASSERT(m_fill_lookahead_size > lookahead_ofs);
uint fill_lookahead_size = m_fill_lookahead_size - lookahead_ofs;
const uint max_match_len = LZHAM_MIN(static_cast<uint>(CLZBase::cMaxMatchLen), fill_lookahead_size);
uint insert_pos = fill_lookahead_pos & m_max_dict_size_mask;
uint c0 = pDict[insert_pos];
uint c1 = pDict[insert_pos + 1];
uint c2 = pDict[insert_pos + 2];
uint h;
if (m_hash24)
h = LZHAM_HASH3_24(c0, c1, c2);
else
h = LZHAM_HASH3_16(c0, c1, c2);
dict_match* pDstMatch = temp_matches;
uint cur_pos = m_hash[h];
m_hash[h] = static_cast<uint>(fill_lookahead_pos);
uint *pLeft = &m_nodes[insert_pos].m_left;
uint *pRight = &m_nodes[insert_pos].m_right;
uint best_match_len = 2;
const uint8* pIns = &pDict[insert_pos];
uint n = m_max_probes;
for ( ; ; )
{
uint delta_pos = fill_lookahead_pos - cur_pos;
if ((n-- == 0) || (!delta_pos) || (delta_pos >= fill_dict_size))
{
*pLeft = 0;
*pRight = 0;
break;
}
uint pos = cur_pos & m_max_dict_size_mask;
// Unfortunately, the initial compare match_len must be 0 because of the way we hash and truncate matches at the end of each block.
uint match_len = 0;
const uint8* pComp = &pDict[pos];
#if LZHAM_PLATFORM_X360 || (LZHAM_USE_UNALIGNED_INT_LOADS == 0) || LZHAM_BIG_ENDIAN_CPU
for ( ; match_len < max_match_len; match_len++)
if (pComp[match_len] != pIns[match_len])
break;
#else
// Compare a qword at a time for a bit more efficiency.
uint64 x = *reinterpret_cast<const uint64 *>(pComp);
uint64 y = *reinterpret_cast<const uint64 *>(pIns);
if ((max_match_len >= 8) && (x == y))
{
const uint64* pComp_cur = reinterpret_cast<const uint64*>(pComp) + 1;
const uint64* pIns_cur = reinterpret_cast<const uint64*>(pIns) + 1;
const uint64* pComp_end = reinterpret_cast<const uint64*>(pComp + max_match_len - 7);
while (pComp_cur < pComp_end)
{
if (*pComp_cur != *pIns_cur)
break;
++pComp_cur;
++pIns_cur;
}
uint alt_match_len = static_cast<uint>(reinterpret_cast<const uint8*>(pComp_cur) - reinterpret_cast<const uint8*>(pComp));
for ( ; alt_match_len < max_match_len; alt_match_len++)
if (pComp[alt_match_len] != pIns[alt_match_len])
break;
match_len = alt_match_len;
}
else
{
if ((uint32)x == (uint32)y)
{
x >>= 32;
y >>= 32;
match_len += 4;
}
if ((uint16)x == (uint16)y)
{
x >>= 16;
y >>= 16;
match_len += 2;
}
if ((uint8)x == (uint8)y)
match_len++;
match_len = math::minimum(match_len, max_match_len);
}
#endif
#ifdef LZVERIFY
uint check_match_len;
for (check_match_len = 0; check_match_len < max_match_len; check_match_len++)
if (pComp[check_match_len] != pIns[check_match_len])
break;
LZHAM_VERIFY(match_len == check_match_len);
#endif
node *pNode = &m_nodes[pos];
if (match_len > best_match_len)
{
pDstMatch->m_len = static_cast<uint16>(match_len - CLZBase::cMinMatchLen);
pDstMatch->m_dist = delta_pos;
pDstMatch++;
best_match_len = match_len;
if (match_len == max_match_len)
{
*pLeft = pNode->m_left;
*pRight = pNode->m_right;
break;
}
}
else if (m_all_matches)
{
pDstMatch->m_len = static_cast<uint16>(match_len - CLZBase::cMinMatchLen);
pDstMatch->m_dist = delta_pos;
pDstMatch++;
}
else if ((best_match_len > 2) && (best_match_len == match_len))
{
uint bestMatchDist = pDstMatch[-1].m_dist;
uint compMatchDist = delta_pos;
uint bestMatchSlot, bestMatchSlotOfs;
m_pLZBase->compute_lzx_position_slot(bestMatchDist, bestMatchSlot, bestMatchSlotOfs);
uint compMatchSlot, compMatchOfs;
m_pLZBase->compute_lzx_position_slot(compMatchDist, compMatchSlot, compMatchOfs);
// If both matches uses the same match slot, choose the one with the offset containing the lowest nibble as these bits separately entropy coded.
// This could choose a match which is further away in the absolute sense, but closer in a coding sense.
if ( (compMatchSlot < bestMatchSlot) ||
((compMatchSlot >= 8) && (compMatchSlot == bestMatchSlot) && ((compMatchOfs & 15) < (bestMatchSlotOfs & 15))) )
{
LZHAM_ASSERT((pDstMatch[-1].m_len + (uint)CLZBase::cMinMatchLen) == best_match_len);
pDstMatch[-1].m_dist = delta_pos;
}
else if ((match_len < max_match_len) && (compMatchSlot <= bestMatchSlot))
{
// Choose the match which has lowest hamming distance in the mismatch byte for a tiny win on binary files.
// TODO: This competes against the prev. optimization.
uint desired_mismatch_byte = pIns[match_len];
uint cur_mismatch_byte = pDict[(insert_pos - bestMatchDist + match_len) & m_max_dict_size_mask];
uint cur_mismatch_dist = g_hamming_dist[cur_mismatch_byte ^ desired_mismatch_byte];
uint new_mismatch_byte = pComp[match_len];
uint new_mismatch_dist = g_hamming_dist[new_mismatch_byte ^ desired_mismatch_byte];
if (new_mismatch_dist < cur_mismatch_dist)
{
LZHAM_ASSERT((pDstMatch[-1].m_len + (uint)CLZBase::cMinMatchLen) == best_match_len);
pDstMatch[-1].m_dist = delta_pos;
}
}
}
uint new_pos;
if (pComp[match_len] < pIns[match_len])
{
*pLeft = cur_pos;
pLeft = &pNode->m_right;
new_pos = pNode->m_right;
}
else
{
*pRight = cur_pos;
pRight = &pNode->m_left;
new_pos = pNode->m_left;
}
if (new_pos == cur_pos)
break;
cur_pos = new_pos;
}
const uint num_matches = (uint)(pDstMatch - temp_matches);
if (num_matches)
{
pDstMatch[-1].m_dist |= 0x80000000;
const uint num_matches_to_write = LZHAM_MIN(num_matches, m_max_matches);
const uint match_ref_ofs = static_cast<uint>(atomic_exchange_add(&m_next_match_ref, num_matches_to_write));
memcpy(&m_matches[match_ref_ofs],
temp_matches + (num_matches - num_matches_to_write),
sizeof(temp_matches[0]) * num_matches_to_write);
// FIXME: This is going to really hurt on platforms requiring export barriers.
LZHAM_MEMORY_EXPORT_BARRIER
atomic_exchange32((atomic32_t*)&m_match_refs[static_cast<uint>(fill_lookahead_pos - m_fill_lookahead_pos)], match_ref_ofs);
}
else
{
atomic_exchange32((atomic32_t*)&m_match_refs[static_cast<uint>(fill_lookahead_pos - m_fill_lookahead_pos)], -2);
}
}
atomic_increment32(&m_num_completed_helper_threads);
}
bool search_accelerator::find_len2_matches()
{
if (!m_digram_hash.size())
{
if (!m_digram_hash.try_resize(cDigramHashSize))
{
LZHAM_LOG_ERROR(9004);
return false;
}
}
if (m_digram_next.size() < m_lookahead_size)
{
if (!m_digram_next.try_resize(m_lookahead_size))
{
LZHAM_LOG_ERROR(9005);
return false;
}
}
uint lookahead_dict_pos = m_lookahead_pos & m_max_dict_size_mask;
for (int lookahead_ofs = 0; lookahead_ofs < ((int)m_lookahead_size - 1); ++lookahead_ofs, ++lookahead_dict_pos)
{
uint c0 = m_dict[lookahead_dict_pos];
uint c1 = m_dict[lookahead_dict_pos + 1];
uint h = hash2_to_12(c0, c1) & (cDigramHashSize - 1);
m_digram_next[lookahead_ofs] = m_digram_hash[h];
m_digram_hash[h] = m_lookahead_pos + lookahead_ofs;
}
m_digram_next[m_lookahead_size - 1] = 0;
return true;
}
uint search_accelerator::get_len2_match(uint lookahead_ofs)
{
if ((m_fill_lookahead_size - lookahead_ofs) < 2)
return 0;
if (!m_digram_next.size())
return 0;
uint cur_pos = m_lookahead_pos + lookahead_ofs;
uint next_match_pos = m_digram_next[cur_pos - m_fill_lookahead_pos];
uint match_dist = cur_pos - next_match_pos;
if ((!match_dist) || (match_dist > CLZBase::cMaxLen2MatchDist) || (match_dist > (m_cur_dict_size + lookahead_ofs)))
return 0;
const uint8* pCur = &m_dict[cur_pos & m_max_dict_size_mask];
const uint8* pMatch = &m_dict[next_match_pos & m_max_dict_size_mask];
if ((pCur[0] == pMatch[0]) && (pCur[1] == pMatch[1]))
return match_dist;
return 0;
}
static inline uint32 bitmix32(uint32 a)
{
a -= (a << 6);
a ^= (a >> 17);
a -= (a << 9);
a ^= (a << 4);
a -= (a << 3);
a ^= (a << 10);
a ^= (a >> 15);
return a;
}
bool search_accelerator::find_all_matches(uint num_bytes)
{
if (!m_matches.try_resize_no_construct(m_max_probes * num_bytes))
{
LZHAM_LOG_ERROR(9006);
return false;
}
if (!m_match_refs.try_resize_no_construct(num_bytes))
{
LZHAM_LOG_ERROR(9007);
return false;
}
memset(m_match_refs.get_ptr(), 0xFF, m_match_refs.size_in_bytes());
m_fill_lookahead_pos = m_lookahead_pos;
m_fill_lookahead_size = num_bytes;
m_fill_dict_size = m_cur_dict_size;
m_next_match_ref = 0;
if ((!m_pTask_pool) || (m_max_helper_threads < 1) || (num_bytes < 1024))
{
find_all_matches_callback_st(0, NULL);
m_num_completed_helper_threads = 0;
}
else
{
for (uint i = num_bytes - 2; i < num_bytes; i++)
{
uint fill_lookahead_pos = m_fill_lookahead_pos + i;
uint insert_pos = fill_lookahead_pos & m_max_dict_size_mask;
m_nodes[insert_pos].m_left = 0;
m_nodes[insert_pos].m_right = 0;
m_match_refs[static_cast<uint>(fill_lookahead_pos - m_fill_lookahead_pos)] = -2;
}
for (uint i = 0; i < m_max_helper_threads; i++)
m_thread_dict_offsets[i].try_resize(0);
uint bytes_to_add = num_bytes - 2;
scoped_perf_section sect(cVarArgs, "****** find_all_matches_prep %u", bytes_to_add);
const uint8* pDict = &m_dict[m_lookahead_pos & m_max_dict_size_mask];
if (m_hash24)
{
uint t = (pDict[0] << 8) | (pDict[1] << 16);
if (math::is_power_of_2(m_max_helper_threads))
{
const uint bitmask = (m_max_helper_threads - 1);
for (uint i = 0; i < bytes_to_add; i++)
{
t = (t >> 8) | (pDict[2] << 16);
LZHAM_ASSERT(t == LZHAM_HASH3_24(pDict[0], pDict[1], pDict[2]));
uint thread_index = bitmix32(t) & bitmask;
if (!m_thread_dict_offsets[thread_index].try_push_back(i))
{
LZHAM_LOG_ERROR(9008);
return false;
}
pDict++;
}
}
else
{
for (uint i = 0; i < bytes_to_add; i++)
{
t = (t >> 8) | (pDict[2] << 16);
LZHAM_ASSERT(t == LZHAM_HASH3_24(pDict[0], pDict[1], pDict[2]));
uint thread_index = bitmix32(t) % m_max_helper_threads;
if (!m_thread_dict_offsets[thread_index].try_push_back(i))
{
LZHAM_LOG_ERROR(9009);
return false;
}
pDict++;
}
}
}
else
{
uint c0 = pDict[0];
uint c1 = pDict[1];
for (uint i = 0; i < bytes_to_add; i++)
{
uint c2 = pDict[2];
uint t = LZHAM_HASH3_16(c0, c1, c2);
c0 = c1;
c1 = c2;
uint thread_index = bitmix32(t) % m_max_helper_threads;
if (!m_thread_dict_offsets[thread_index].try_push_back(i))
{
LZHAM_LOG_ERROR(9010);
return false;
}
pDict++;
}
}
m_num_completed_helper_threads = 0;
if (!m_pTask_pool->queue_multiple_object_tasks(this, &search_accelerator::find_all_matches_callback_mt, 0, m_max_helper_threads))
{
LZHAM_LOG_ERROR(9011);
return false;
}
}
return m_len2_matches ? find_len2_matches() : true;
}
bool search_accelerator::add_bytes_begin(uint num_bytes, const uint8* pBytes)
{
LZHAM_ASSERT(num_bytes <= m_max_dict_size);
LZHAM_ASSERT(!m_lookahead_size);
uint add_pos = m_lookahead_pos & m_max_dict_size_mask;
LZHAM_ASSERT((add_pos + num_bytes) <= m_max_dict_size);
memcpy(&m_dict[add_pos], pBytes, num_bytes);
uint dict_bytes_to_mirror = LZHAM_MIN(static_cast<uint>(CLZBase::cMaxHugeMatchLen), m_max_dict_size);
if (add_pos < dict_bytes_to_mirror)
memcpy(&m_dict[m_max_dict_size], &m_dict[0], dict_bytes_to_mirror);
m_lookahead_size = num_bytes;
uint max_possible_dict_size = m_max_dict_size - num_bytes;
m_cur_dict_size = LZHAM_MIN(m_cur_dict_size, max_possible_dict_size);
m_next_match_ref = 0;
return find_all_matches(num_bytes);
}
void search_accelerator::add_bytes_end()
{
if (m_pTask_pool)
{
m_pTask_pool->join();
}
LZHAM_ASSERT((uint)m_next_match_ref <= m_matches.size());
}
dict_match* search_accelerator::find_matches(uint lookahead_ofs, bool spin)
{
LZHAM_ASSERT(lookahead_ofs < m_lookahead_size);
const uint match_ref_ofs = static_cast<uint>(m_lookahead_pos - m_fill_lookahead_pos + lookahead_ofs);
int match_ref;
uint spin_count = 0;
// This may spin until the match finder job(s) catch up to the caller's lookahead position.
for ( ; ; )
{
match_ref = static_cast<int>(m_match_refs[match_ref_ofs]);
if (match_ref == -2)
return NULL;
else if (match_ref != -1)
break;
spin_count++;
const uint cMaxSpinCount = 1000;
if ((spin) && (spin_count < cMaxSpinCount))
{
lzham_yield_processor();
lzham_yield_processor();
lzham_yield_processor();
lzham_yield_processor();
lzham_yield_processor();
lzham_yield_processor();
lzham_yield_processor();
lzham_yield_processor();
LZHAM_MEMORY_IMPORT_BARRIER
}
else
{
scoped_perf_section sect("find_matches_sleep");
spin_count = cMaxSpinCount;
lzham_sleep(1);
}
}
LZHAM_MEMORY_IMPORT_BARRIER
return &m_matches[match_ref];
}
void search_accelerator::advance_bytes(uint num_bytes)
{
LZHAM_ASSERT(num_bytes <= m_lookahead_size);
m_lookahead_pos += num_bytes;
m_lookahead_size -= num_bytes;
m_cur_dict_size += num_bytes;
LZHAM_ASSERT(m_cur_dict_size <= m_max_dict_size);
}
}
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