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/*-
* Copyright (c) 2014-present MongoDB, Inc.
* Copyright (c) 2008-2014 WiredTiger, Inc.
* All rights reserved.
*
* See the file LICENSE for redistribution information.
*/
#ifdef HAVE_X86INTRIN_H
#if !defined(_MSC_VER) && !defined(_lint)
#include <x86intrin.h>
#endif
#endif
#if defined(HAVE_ARM_NEON_INTRIN_H)
#include <arm_neon.h>
#endif
/* 16B alignment */
#define WT_ALIGNED_16(p) (((uintptr_t)(p)&0x0f) == 0)
#define WT_VECTOR_SIZE 16 /* chunk size */
/*
* __wt_lex_compare --
* Lexicographic comparison routine. Returns: < 0 if user_item is lexicographically < tree_item,
* = 0 if user_item is lexicographically = tree_item, > 0 if user_item is lexicographically >
* tree_item. We use the names "user" and "tree" so it's clear in the btree code which the
* application is looking at when we call its comparison function.
*/
static inline int
__wt_lex_compare(const WT_ITEM *user_item, const WT_ITEM *tree_item)
{
size_t len, usz, tsz;
const uint8_t *userp, *treep;
usz = user_item->size;
tsz = tree_item->size;
len = WT_MIN(usz, tsz);
userp = (const uint8_t *)user_item->data;
treep = (const uint8_t *)tree_item->data;
#ifdef HAVE_X86INTRIN_H
/* Use vector instructions if we'll execute at least 2 of them. */
if (len >= WT_VECTOR_SIZE * 2) {
size_t remain;
__m128i res_eq, u, t;
remain = len % WT_VECTOR_SIZE;
len -= remain;
if (WT_ALIGNED_16(userp) && WT_ALIGNED_16(treep))
for (; len > 0;
len -= WT_VECTOR_SIZE, userp += WT_VECTOR_SIZE, treep += WT_VECTOR_SIZE) {
u = _mm_load_si128((const __m128i *)userp);
t = _mm_load_si128((const __m128i *)treep);
res_eq = _mm_cmpeq_epi8(u, t);
if (_mm_movemask_epi8(res_eq) != 65535)
break;
}
else
for (; len > 0;
len -= WT_VECTOR_SIZE, userp += WT_VECTOR_SIZE, treep += WT_VECTOR_SIZE) {
u = _mm_loadu_si128((const __m128i *)userp);
t = _mm_loadu_si128((const __m128i *)treep);
res_eq = _mm_cmpeq_epi8(u, t);
if (_mm_movemask_epi8(res_eq) != 65535)
break;
}
len += remain;
}
#elif defined(HAVE_ARM_NEON_INTRIN_H)
/* Use vector instructions if we'll execute at least 1 of them. */
if (len >= WT_VECTOR_SIZE) {
size_t remain;
uint8x16_t res_eq, u, t;
remain = len % WT_VECTOR_SIZE;
len -= remain;
for (; len > 0; len -= WT_VECTOR_SIZE, userp += WT_VECTOR_SIZE, treep += WT_VECTOR_SIZE) {
u = vld1q_u8(userp);
t = vld1q_u8(treep);
res_eq = vceqq_u8(u, t);
if (vminvq_u8(res_eq) != 255)
break;
}
len += remain;
}
#endif
/*
* Use the non-vectorized version for the remaining bytes and for the small key sizes.
*/
for (; len > 0; --len, ++userp, ++treep)
if (*userp != *treep)
return (*userp < *treep ? -1 : 1);
/* Contents are equal up to the smallest length. */
return ((usz == tsz) ? 0 : (usz < tsz) ? -1 : 1);
}
/*
* __wt_compare --
* The same as __wt_lex_compare, but using the application's collator function when configured.
*/
static inline int
__wt_compare(WT_SESSION_IMPL *session, WT_COLLATOR *collator, const WT_ITEM *user_item,
const WT_ITEM *tree_item, int *cmpp)
{
if (collator == NULL) {
*cmpp = __wt_lex_compare(user_item, tree_item);
return (0);
}
return (collator->compare(collator, &session->iface, user_item, tree_item, cmpp));
}
/*
* __wt_compare_bounds --
* Return if the cursor key is within the bounded range. If upper is True, this indicates a next
* call and the key is checked against the upper bound. If upper is False, this indicates a prev
* call and the key is then checked against the lower bound.
*/
static inline int
__wt_compare_bounds(WT_SESSION_IMPL *session, WT_CURSOR *cursor, WT_ITEM *key, uint64_t recno,
bool upper, bool *key_out_of_bounds)
{
uint64_t recno_bound;
int cmpp;
cmpp = 0;
recno_bound = 0;
WT_STAT_CONN_DATA_INCR(session, cursor_bounds_comparisons);
if (upper) {
WT_ASSERT(session, WT_DATA_IN_ITEM(&cursor->upper_bound));
if (CUR2BT(cursor)->type == BTREE_ROW)
WT_RET(
__wt_compare(session, CUR2BT(cursor)->collator, key, &cursor->upper_bound, &cmpp));
else
/* Unpack the raw recno buffer into integer variable. */
WT_RET(__wt_struct_unpack(
session, cursor->upper_bound.data, cursor->upper_bound.size, "q", &recno_bound));
if (F_ISSET(cursor, WT_CURSTD_BOUND_UPPER_INCLUSIVE))
*key_out_of_bounds =
CUR2BT(cursor)->type == BTREE_ROW ? (cmpp > 0) : (recno > recno_bound);
else
*key_out_of_bounds =
CUR2BT(cursor)->type == BTREE_ROW ? (cmpp >= 0) : (recno >= recno_bound);
} else {
WT_ASSERT(session, WT_DATA_IN_ITEM(&cursor->lower_bound));
if (CUR2BT(cursor)->type == BTREE_ROW)
WT_RET(
__wt_compare(session, CUR2BT(cursor)->collator, key, &cursor->lower_bound, &cmpp));
else
/* Unpack the raw recno buffer into integer variable. */
WT_RET(__wt_struct_unpack(
session, cursor->lower_bound.data, cursor->lower_bound.size, "q", &recno_bound));
if (F_ISSET(cursor, WT_CURSTD_BOUND_LOWER_INCLUSIVE))
*key_out_of_bounds =
CUR2BT(cursor)->type == BTREE_ROW ? (cmpp < 0) : (recno < recno_bound);
else
*key_out_of_bounds =
CUR2BT(cursor)->type == BTREE_ROW ? (cmpp <= 0) : (recno <= recno_bound);
}
return (0);
}
/*
* __wt_lex_compare_skip --
* Lexicographic comparison routine, skipping leading bytes. Returns: < 0 if user_item is
* lexicographically < tree_item = 0 if user_item is lexicographically = tree_item > 0 if
* user_item is lexicographically > tree_item We use the names "user" and "tree" so it's clear
* in the btree code which the application is looking at when we call its comparison function.
*/
static inline int
__wt_lex_compare_skip(const WT_ITEM *user_item, const WT_ITEM *tree_item, size_t *matchp)
{
size_t len, usz, tsz;
const uint8_t *userp, *treep;
int ret_val;
usz = user_item->size;
tsz = tree_item->size;
len = WT_MIN(usz, tsz) - *matchp;
userp = (const uint8_t *)user_item->data + *matchp;
treep = (const uint8_t *)tree_item->data + *matchp;
#ifdef HAVE_X86INTRIN_H
/* Use vector instructions if we'll execute at least 2 of them. */
if (len >= WT_VECTOR_SIZE * 2) {
size_t remain;
__m128i res_eq, u, t;
remain = len % WT_VECTOR_SIZE;
len -= remain;
if (WT_ALIGNED_16(userp) && WT_ALIGNED_16(treep))
for (; len > 0; len -= WT_VECTOR_SIZE, userp += WT_VECTOR_SIZE, treep += WT_VECTOR_SIZE,
*matchp += WT_VECTOR_SIZE) {
u = _mm_load_si128((const __m128i *)userp);
t = _mm_load_si128((const __m128i *)treep);
res_eq = _mm_cmpeq_epi8(u, t);
if (_mm_movemask_epi8(res_eq) != 65535)
break;
}
else
for (; len > 0; len -= WT_VECTOR_SIZE, userp += WT_VECTOR_SIZE, treep += WT_VECTOR_SIZE,
*matchp += WT_VECTOR_SIZE) {
u = _mm_loadu_si128((const __m128i *)userp);
t = _mm_loadu_si128((const __m128i *)treep);
res_eq = _mm_cmpeq_epi8(u, t);
if (_mm_movemask_epi8(res_eq) != 65535)
break;
}
len += remain;
}
#elif defined(HAVE_ARM_NEON_INTRIN_H)
/* Use vector instructions if we'll execute at least 1 of them. */
if (len >= WT_VECTOR_SIZE) {
size_t remain;
uint8x16_t res_eq, u, t;
remain = len % WT_VECTOR_SIZE;
len -= remain;
if (WT_ALIGNED_16(userp) && WT_ALIGNED_16(treep))
for (; len > 0; len -= WT_VECTOR_SIZE, userp += WT_VECTOR_SIZE, treep += WT_VECTOR_SIZE,
*matchp += WT_VECTOR_SIZE) {
u = vld1q_u8(userp);
t = vld1q_u8(treep);
res_eq = vceqq_u8(u, t);
if (vminvq_u8(res_eq) != 255)
break;
}
len += remain;
}
#endif
ret_val = 0;
/*
* Use the non-vectorized version for the remaining bytes and for the small key sizes.
*/
for (; len > 0; --len, ++userp, ++treep, ++*matchp)
if (*userp != *treep) {
ret_val = *userp < *treep ? -1 : 1;
break;
}
/* Contents are equal up to the smallest length. */
if (ret_val == 0)
ret_val = ((usz == tsz) ? 0 : (usz < tsz) ? -1 : 1);
/* In diagnostic mode ensure that short comparisons work as expected */
#ifdef HAVE_DIAGNOSTIC
{
int full_cmp_ret;
full_cmp_ret = __wt_lex_compare(user_item, tree_item);
WT_ASSERT_ALWAYS(NULL, full_cmp_ret == ret_val,
"Comparison that skipped prefix returned different result than a full comparison");
}
#endif
return (ret_val);
}
/*
* __wt_compare_skip --
* The same as __wt_lex_compare_skip, but using the application's collator function when
* configured.
*/
static inline int
__wt_compare_skip(WT_SESSION_IMPL *session, WT_COLLATOR *collator, const WT_ITEM *user_item,
const WT_ITEM *tree_item, int *cmpp, size_t *matchp)
{
if (collator == NULL) {
*cmpp = __wt_lex_compare_skip(user_item, tree_item, matchp);
return (0);
}
return (collator->compare(collator, &session->iface, user_item, tree_item, cmpp));
}
/*
* __wt_lex_compare_short --
* Lexicographic comparison routine for short keys. Returns: < 0 if user_item is
* lexicographically < tree_item = 0 if user_item is lexicographically = tree_item > 0 if
* user_item is lexicographically > tree_item We use the names "user" and "tree" so it's clear
* in the btree code which the application is looking at when we call its comparison function.
*/
static inline int
__wt_lex_compare_short(const WT_ITEM *user_item, const WT_ITEM *tree_item)
{
size_t len, usz, tsz;
const uint8_t *userp, *treep;
usz = user_item->size;
tsz = tree_item->size;
len = WT_MIN(usz, tsz);
userp = (const uint8_t *)user_item->data;
treep = (const uint8_t *)tree_item->data;
/*
* The maximum packed uint64_t is 9B, catch row-store objects using packed record numbers as keys.
*
* Don't use a #define to compress this case statement: gcc7 complains about implicit fallthrough
* and doesn't support explicit fallthrough comments in macros.
*/
#define WT_COMPARE_SHORT_MAXLEN 9
switch (len) {
case 9:
if (*userp != *treep)
break;
++userp;
++treep;
/* FALLTHROUGH */
case 8:
if (*userp != *treep)
break;
++userp;
++treep;
/* FALLTHROUGH */
case 7:
if (*userp != *treep)
break;
++userp;
++treep;
/* FALLTHROUGH */
case 6:
if (*userp != *treep)
break;
++userp;
++treep;
/* FALLTHROUGH */
case 5:
if (*userp != *treep)
break;
++userp;
++treep;
/* FALLTHROUGH */
case 4:
if (*userp != *treep)
break;
++userp;
++treep;
/* FALLTHROUGH */
case 3:
if (*userp != *treep)
break;
++userp;
++treep;
/* FALLTHROUGH */
case 2:
if (*userp != *treep)
break;
++userp;
++treep;
/* FALLTHROUGH */
case 1:
if (*userp != *treep)
break;
/* Contents are equal up to the smallest length. */
return ((usz == tsz) ? 0 : (usz < tsz) ? -1 : 1);
}
return (*userp < *treep ? -1 : 1);
}
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