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https://github.com/isar/libmdbx.git
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mdbx: микро-оптимизация cmp_int().
This commit is contained in:
Леонид Юрьев (Leonid Yuriev)
parent
be05037906
commit
5317e516d2
225
src/core.c
225
src/core.c
@ -3381,9 +3381,6 @@ static int __must_check_result setup_dbx(MDBX_dbx *const dbx,
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const MDBX_db *const db,
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const unsigned pagesize);
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static MDBX_cmp_func cmp_lexical, cmp_reverse, cmp_int_align4, cmp_int_align2,
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cmp_int_unaligned, cmp_lenfast;
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static __inline MDBX_cmp_func *get_default_keycmp(unsigned flags);
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static __inline MDBX_cmp_func *get_default_datacmp(unsigned flags);
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@ -11832,6 +11829,116 @@ fail:
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goto provide_latency;
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}
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static __always_inline int cmp_int_inline(const size_t expected_alignment,
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const MDBX_val *a,
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const MDBX_val *b) {
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if (likely(a->iov_len == b->iov_len)) {
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if (sizeof(size_t) > 7 && likely(a->iov_len == 8))
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return CMP2INT(unaligned_peek_u64(expected_alignment, a->iov_base),
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unaligned_peek_u64(expected_alignment, b->iov_base));
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if (likely(a->iov_len == 4))
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return CMP2INT(unaligned_peek_u32(expected_alignment, a->iov_base),
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unaligned_peek_u32(expected_alignment, b->iov_base));
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if (sizeof(size_t) < 8 && likely(a->iov_len == 8))
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return CMP2INT(unaligned_peek_u64(expected_alignment, a->iov_base),
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unaligned_peek_u64(expected_alignment, b->iov_base));
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}
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ERROR("mismatch and/or invalid size %p.%zu/%p.%zu for INTEGERKEY/INTEGERDUP",
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a->iov_base, a->iov_len, b->iov_base, b->iov_len);
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return 0;
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}
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__hot static int cmp_int_unaligned(const MDBX_val *a, const MDBX_val *b) {
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return cmp_int_inline(1, a, b);
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}
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/* Compare two items pointing at 2-byte aligned unsigned int's. */
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#if MDBX_UNALIGNED_OK < 2 || \
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(MDBX_DEBUG || MDBX_FORCE_ASSERTIONS || !defined(NDEBUG))
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__hot static int cmp_int_align2(const MDBX_val *a, const MDBX_val *b) {
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return cmp_int_inline(2, a, b);
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}
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#else
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#define cmp_int_align2 cmp_int_unaligned
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#endif /* !MDBX_UNALIGNED_OK || debug */
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/* Compare two items pointing at aligned unsigned int's. */
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#if MDBX_UNALIGNED_OK < 4 || \
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(MDBX_DEBUG || MDBX_FORCE_ASSERTIONS || !defined(NDEBUG))
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__hot static int cmp_int_align4(const MDBX_val *a, const MDBX_val *b) {
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return cmp_int_inline(4, a, b);
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}
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#else
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#define cmp_int_align4 cmp_int_unaligned
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#endif /* !MDBX_UNALIGNED_OK || debug */
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/* Compare two items lexically */
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__hot static int cmp_lexical(const MDBX_val *a, const MDBX_val *b) {
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if (a->iov_len == b->iov_len)
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return a->iov_len ? memcmp(a->iov_base, b->iov_base, a->iov_len) : 0;
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const int diff_len = (a->iov_len < b->iov_len) ? -1 : 1;
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const size_t shortest = (a->iov_len < b->iov_len) ? a->iov_len : b->iov_len;
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int diff_data = shortest ? memcmp(a->iov_base, b->iov_base, shortest) : 0;
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return likely(diff_data) ? diff_data : diff_len;
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}
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MDBX_NOTHROW_PURE_FUNCTION static __always_inline unsigned
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tail3le(const uint8_t *p, size_t l) {
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STATIC_ASSERT(sizeof(unsigned) > 2);
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// 1: 0 0 0
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// 2: 0 1 1
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// 3: 0 1 2
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return p[0] | p[l >> 1] << 8 | p[l - 1] << 16;
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}
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/* Compare two items in reverse byte order */
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__hot static int cmp_reverse(const MDBX_val *a, const MDBX_val *b) {
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const size_t shortest = (a->iov_len < b->iov_len) ? a->iov_len : b->iov_len;
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if (likely(shortest)) {
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const uint8_t *pa = ptr_disp(a->iov_base, a->iov_len);
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const uint8_t *pb = ptr_disp(b->iov_base, b->iov_len);
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const uint8_t *const end = pa - shortest;
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do {
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int diff = *--pa - *--pb;
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if (likely(diff))
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return diff;
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} while (pa != end);
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}
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return CMP2INT(a->iov_len, b->iov_len);
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}
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/* Fast non-lexically comparator */
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__hot static int cmp_lenfast(const MDBX_val *a, const MDBX_val *b) {
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int diff = CMP2INT(a->iov_len, b->iov_len);
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return (likely(diff) || a->iov_len == 0)
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? diff
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: memcmp(a->iov_base, b->iov_base, a->iov_len);
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}
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__hot static bool eq_fast_slowpath(const uint8_t *a, const uint8_t *b,
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size_t l) {
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if (likely(l > 3)) {
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if (MDBX_UNALIGNED_OK >= 4 && likely(l < 9))
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return ((unaligned_peek_u32(1, a) - unaligned_peek_u32(1, b)) |
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(unaligned_peek_u32(1, a + l - 4) -
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unaligned_peek_u32(1, b + l - 4))) == 0;
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if (MDBX_UNALIGNED_OK >= 8 && sizeof(size_t) > 7 && likely(l < 17))
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return ((unaligned_peek_u64(1, a) - unaligned_peek_u64(1, b)) |
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(unaligned_peek_u64(1, a + l - 8) -
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unaligned_peek_u64(1, b + l - 8))) == 0;
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return memcmp(a, b, l) == 0;
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}
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if (likely(l))
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return tail3le(a, l) == tail3le(b, l);
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return true;
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}
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static __always_inline bool eq_fast(const MDBX_val *a, const MDBX_val *b) {
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return unlikely(a->iov_len == b->iov_len) &&
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eq_fast_slowpath(a->iov_base, b->iov_base, a->iov_len);
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}
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static int validate_meta(MDBX_env *env, MDBX_meta *const meta,
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const MDBX_page *const page,
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const unsigned meta_number, unsigned *guess_pagesize) {
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@ -15151,118 +15258,6 @@ __cold int mdbx_env_close(MDBX_env *env) {
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}
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#endif /* LIBMDBX_NO_EXPORTS_LEGACY_API */
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/* Compare two items pointing at aligned unsigned int's. */
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__hot static int cmp_int_align4(const MDBX_val *a, const MDBX_val *b) {
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eASSERT(NULL, a->iov_len == b->iov_len);
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switch (a->iov_len) {
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case 4:
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return CMP2INT(unaligned_peek_u32(4, a->iov_base),
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unaligned_peek_u32(4, b->iov_base));
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case 8:
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return CMP2INT(unaligned_peek_u64(4, a->iov_base),
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unaligned_peek_u64(4, b->iov_base));
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default:
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mdbx_panic("invalid size %zu for INTEGERKEY/INTEGERDUP", a->iov_len);
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return 0;
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}
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}
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/* Compare two items pointing at 2-byte aligned unsigned int's. */
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__hot static int cmp_int_align2(const MDBX_val *a, const MDBX_val *b) {
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eASSERT(NULL, a->iov_len == b->iov_len);
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switch (a->iov_len) {
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case 4:
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return CMP2INT(unaligned_peek_u32(2, a->iov_base),
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unaligned_peek_u32(2, b->iov_base));
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case 8:
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return CMP2INT(unaligned_peek_u64(2, a->iov_base),
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unaligned_peek_u64(2, b->iov_base));
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default:
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mdbx_panic("invalid size %zu for INTEGERKEY/INTEGERDUP", a->iov_len);
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return 0;
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}
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}
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/* Compare two items pointing at unsigned values with unknown alignment.
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*
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* This is also set as MDBX_INTEGERDUP|MDBX_DUPFIXED's MDBX_dbx.md_dcmp. */
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__hot static int cmp_int_unaligned(const MDBX_val *a, const MDBX_val *b) {
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eASSERT(NULL, a->iov_len == b->iov_len);
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switch (a->iov_len) {
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case 4:
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return CMP2INT(unaligned_peek_u32(1, a->iov_base),
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unaligned_peek_u32(1, b->iov_base));
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case 8:
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return CMP2INT(unaligned_peek_u64(1, a->iov_base),
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unaligned_peek_u64(1, b->iov_base));
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default:
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mdbx_panic("invalid size %zu for INTEGERKEY/INTEGERDUP", a->iov_len);
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return 0;
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}
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}
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/* Compare two items lexically */
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__hot static int cmp_lexical(const MDBX_val *a, const MDBX_val *b) {
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if (a->iov_len == b->iov_len)
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return a->iov_len ? memcmp(a->iov_base, b->iov_base, a->iov_len) : 0;
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const int diff_len = (a->iov_len < b->iov_len) ? -1 : 1;
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const size_t shortest = (a->iov_len < b->iov_len) ? a->iov_len : b->iov_len;
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int diff_data = shortest ? memcmp(a->iov_base, b->iov_base, shortest) : 0;
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return likely(diff_data) ? diff_data : diff_len;
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}
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/* Compare two items in reverse byte order */
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__hot static int cmp_reverse(const MDBX_val *a, const MDBX_val *b) {
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const size_t shortest = (a->iov_len < b->iov_len) ? a->iov_len : b->iov_len;
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if (likely(shortest)) {
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const uint8_t *pa = ptr_disp(a->iov_base, a->iov_len);
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const uint8_t *pb = ptr_disp(b->iov_base, b->iov_len);
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const uint8_t *const end = pa - shortest;
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do {
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int diff = *--pa - *--pb;
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if (likely(diff))
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return diff;
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} while (pa != end);
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}
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return CMP2INT(a->iov_len, b->iov_len);
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}
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/* Fast non-lexically comparator */
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__hot static int cmp_lenfast(const MDBX_val *a, const MDBX_val *b) {
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int diff = CMP2INT(a->iov_len, b->iov_len);
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return likely(diff) || a->iov_len == 0
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? diff
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: memcmp(a->iov_base, b->iov_base, a->iov_len);
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}
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__hot static bool eq_fast_slowpath(const uint8_t *a, const uint8_t *b,
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size_t l) {
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if (likely(l > 3)) {
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if (MDBX_UNALIGNED_OK >= 4 && likely(l < 9))
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return ((unaligned_peek_u32(1, a) - unaligned_peek_u32(1, b)) |
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(unaligned_peek_u32(1, a + l - 4) -
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unaligned_peek_u32(1, b + l - 4))) == 0;
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if (MDBX_UNALIGNED_OK >= 8 && sizeof(size_t) > 7 && likely(l < 17))
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return ((unaligned_peek_u64(1, a) - unaligned_peek_u64(1, b)) |
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(unaligned_peek_u64(1, a + l - 8) -
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unaligned_peek_u64(1, b + l - 8))) == 0;
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return memcmp(a, b, l) == 0;
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}
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if (likely(l)) {
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STATIC_ASSERT(sizeof(int) > 2);
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const unsigned a3 = a[0] << 16 | a[l >> 1] << 8 | a[l - 1];
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const unsigned b3 = b[0] << 16 | b[l >> 1] << 8 | b[l - 1];
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return a3 == b3;
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}
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return true;
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}
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static __always_inline bool eq_fast(const MDBX_val *a, const MDBX_val *b) {
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return unlikely(a->iov_len == b->iov_len) &&
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eq_fast_slowpath(a->iov_base, b->iov_base, a->iov_len);
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}
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/* Search for key within a page, using binary search.
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* Returns the smallest entry larger or equal to the key.
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* Updates the cursor index with the index of the found entry.
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