mirror of
https://github.com/isar/libmdbx.git
synced 2025-01-02 00:34:13 +08:00
lmdb: rework key/data comparison to avoid alignment errors.
Change-Id: I291b50ad6f7dd18f6cbdef34028d917e10166cf1
This commit is contained in:
parent
41d38a1e4d
commit
b60f510355
119
mdb.c
119
mdb.c
@ -1194,7 +1194,7 @@ static void mdb_default_cmp(MDB_txn *txn, MDB_dbi dbi);
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static int mdb_reader_check0(MDB_env *env, int rlocked, int *dead);
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/** @cond */
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static MDB_cmp_func mdb_cmp_memn, mdb_cmp_memnr, mdb_cmp_int_a, mdb_cmp_int_na;
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static MDB_cmp_func mdb_cmp_memn, mdb_cmp_memnr, mdb_cmp_int_ai, mdb_cmp_int_a2, mdb_cmp_int_ua;
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/** @endcond */
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/** Return the library version info. */
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@ -4649,7 +4649,7 @@ mdb_env_open(MDB_env *env, const char *path, unsigned flags, mode_t mode)
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rc = ENOMEM;
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goto leave;
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}
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env->me_dbxs[FREE_DBI].md_cmp = mdb_cmp_int_a; /* aligned MDB_INTEGERKEY */
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env->me_dbxs[FREE_DBI].md_cmp = mdb_cmp_int_ai; /* aligned MDB_INTEGERKEY */
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/* For RDONLY, get lockfile after we know datafile exists */
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if (!(flags & MDB_RDONLY)) {
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@ -4818,29 +4818,26 @@ mdb_env_close_ex(MDB_env *env, int dont_sync)
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free(env);
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}
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/** Compare two items pointing at aligned unsigned int's.
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*
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* This is also set as #MDB_INTEGERDUP|#MDB_DUPFIXED's #MDB_dbx.%md_dcmp.
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*/
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/** Compare two items pointing at aligned unsigned int's. */
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static int
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mdb_cmp_int_a(const MDB_val *a, const MDB_val *b)
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mdb_cmp_int_ai(const MDB_val *a, const MDB_val *b)
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{
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mdb_assert(NULL, a->mv_size == b->mv_size);
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mdb_assert(NULL, 0 == (uintptr_t) a->mv_data % sizeof(int));
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mdb_assert(NULL, 0 == (uintptr_t) a->mv_data % sizeof(int)
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&& 0 == (uintptr_t) b->mv_data % sizeof(int));
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if (sizeof(int) != sizeof(size_t) && likely(a->mv_size == sizeof(size_t)))
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if (sizeof(int) != sizeof(size_t) && likely(a->mv_size == sizeof(size_t))) {
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return (*(size_t *)a->mv_data < *(size_t *)b->mv_data) ? -1 :
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*(size_t *)a->mv_data > *(size_t *)b->mv_data;
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}
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mdb_assert(NULL, a->mv_size == sizeof(int) );
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return *(int *)a->mv_data - *(int *)b->mv_data;
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}
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/** Compare two items pointing at unsigneds of unknown alignment.
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* Nodes and keys are guaranteed to be 2-byte aligned.
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*/
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/** Compare two items pointing at 2-byte aligned unsigned int's. */
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static int
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mdb_cmp_int_na(const MDB_val *a, const MDB_val *b)
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mdb_cmp_int_a2(const MDB_val *a, const MDB_val *b)
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{
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mdb_assert(NULL, a->mv_size == b->mv_size);
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mdb_assert(NULL, 0 == a->mv_size % sizeof(short));
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@ -4854,29 +4851,68 @@ mdb_cmp_int_na(const MDB_val *a, const MDB_val *b)
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mdb_assert(NULL, a->mv_size == sizeof(int) );
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return *(int *)a->mv_data - *(int *)b->mv_data;
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#elif BYTE_ORDER == LITTLE_ENDIAN
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unsigned short *u, *c;
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int x;
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u = (unsigned short *) ((char *) a->mv_data + a->mv_size);
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c = (unsigned short *) ((char *) b->mv_data + a->mv_size);
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do {
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x = *--u - *--c;
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} while(!x && u > (unsigned short *)a->mv_data);
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return x;
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#else
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unsigned short *u, *c, *end;
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int x;
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{
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int x;
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unsigned short *u, *c;
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end = (unsigned short *) ((char *) a->mv_data + a->mv_size);
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u = (unsigned short *)a->mv_data;
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c = (unsigned short *)b->mv_data;
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do {
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x = *u++ - *c++;
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} while(!x && u < end);
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return x;
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#endif /* BYTE_ORDER & MISALIGNED_OK */
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#if BYTE_ORDER == LITTLE_ENDIAN
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u = (unsigned short *) ((char *) a->mv_data + a->mv_size);
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c = (unsigned short *) ((char *) b->mv_data + a->mv_size);
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do {
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x = *--u - *--c;
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} while(!x && u > (unsigned short *)a->mv_data);
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#else /* BYTE_ORDER */
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unsigned short *end;
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end = (unsigned short *) ((char *) a->mv_data + a->mv_size);
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u = (unsigned short *)a->mv_data;
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c = (unsigned short *)b->mv_data;
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do {
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x = *u++ - *c++;
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} while(!x && u < end);
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#endif /* BYTE_ORDER */
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return x;
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}
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#endif /* MISALIGNED_OK */
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}
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/** Compare two items pointing at unsigneds of unknown alignment.
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*
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* This is also set as #MDB_INTEGERDUP|#MDB_DUPFIXED's #MDB_dbx.%md_dcmp.
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*/
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static int
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mdb_cmp_int_ua(const MDB_val *a, const MDB_val *b)
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{
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mdb_assert(NULL, a->mv_size == b->mv_size);
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#if MISALIGNED_OK
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if (sizeof(int) != sizeof(size_t) && likely(a->mv_size == sizeof(size_t)))
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return (*(size_t *)a->mv_data < *(size_t *)b->mv_data) ? -1 :
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*(size_t *)a->mv_data > *(size_t *)b->mv_data;
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mdb_assert(NULL, a->mv_size == sizeof(int) );
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return *(int *)a->mv_data - *(int *)b->mv_data;
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#else
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mdb_assert(NULL, a->mv_size == sizeof(int) || a->mv_size == sizeof(size_t));
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{
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#if BYTE_ORDER == LITTLE_ENDIAN
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const unsigned char *p1, *p2;
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int diff;
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p1 = (const unsigned char *)a->mv_data + a->mv_size;
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p2 = (const unsigned char *)b->mv_data + a->mv_size;
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do {
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diff = *--p1 - *--p2;
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if (diff)
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return diff;
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} while(p1 != a->mv_data);
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return 0;
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}
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#else /* BYTE_ORDER */
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return memcmp(a->mv_data, b->mv_data, a->mv_size);
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#endif /* BYTE_ORDER */
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#endif /* MISALIGNED_OK */
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}
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/** Compare two items lexically */
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@ -4954,10 +4990,10 @@ mdb_node_search(MDB_cursor *mc, MDB_val *key, int *exactp)
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cmp = mc->mc_dbx->md_cmp;
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/* Branch pages have no data, so if using integer keys,
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* alignment is guaranteed. Use faster mdb_cmp_int_a.
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* alignment is guaranteed. Use faster mdb_cmp_int_ai.
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*/
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if (cmp == mdb_cmp_int_na && IS_BRANCH(mp))
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cmp = mdb_cmp_int_a;
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if (cmp == mdb_cmp_int_a2 && IS_BRANCH(mp))
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cmp = mdb_cmp_int_ai;
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if (IS_LEAF2(mp)) {
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nodekey.mv_size = mc->mc_db->md_xsize;
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@ -9124,17 +9160,16 @@ mdb_env_info(MDB_env *env, MDB_envinfo *arg)
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static void
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mdb_default_cmp(MDB_txn *txn, MDB_dbi dbi)
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{
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uint16_t f = txn->mt_dbs[dbi].md_flags;
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unsigned f = txn->mt_dbs[dbi].md_flags;
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txn->mt_dbxs[dbi].md_cmp =
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(f & MDB_REVERSEKEY) ? mdb_cmp_memnr :
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(f & MDB_INTEGERKEY) ? mdb_cmp_int_na : mdb_cmp_memn;
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(f & MDB_INTEGERKEY) ? mdb_cmp_int_a2 : mdb_cmp_memn;
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txn->mt_dbxs[dbi].md_dcmp =
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!(f & MDB_DUPSORT) ? 0 :
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((f & MDB_INTEGERDUP)
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? ((f & MDB_DUPFIXED) ? mdb_cmp_int_a : mdb_cmp_int_na)
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: ((f & MDB_REVERSEDUP) ? mdb_cmp_memnr : mdb_cmp_memn));
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((f & MDB_INTEGERDUP) ? mdb_cmp_int_ua :
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((f & MDB_REVERSEDUP) ? mdb_cmp_memnr : mdb_cmp_memn));
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}
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int mdb_dbi_open(MDB_txn *txn, const char *name, unsigned flags, MDB_dbi *dbi)
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