diff options
author | Pauli <pauli@openssl.org> | 2022-05-20 10:15:55 +1000 |
---|---|---|
committer | Dmitry Belyavskiy <beldmit@gmail.com> | 2022-05-21 21:53:39 +0200 |
commit | a4e21d18d5b7cb4fef66c10f13b1b3b55945439f (patch) | |
tree | 3bc17e5c5d96c072a7fc7afad3db202cec62b103 /crypto/lhash | |
parent | b00cf0e790661636e1df1026554f712cc513592d (diff) |
performance: improve ossl_lh_strcasehash
This improvement seems to roughly halve the time it takes to run the
ossl_lh_strcasehash function.
It should have no impact on the strings we hash and search for often (algorithm
names, property strings).
Reviewed-by: Dmitry Belyavskiy <beldmit@gmail.com>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/18354)
Diffstat (limited to 'crypto/lhash')
-rw-r--r-- | crypto/lhash/lhash.c | 21 |
1 files changed, 20 insertions, 1 deletions
diff --git a/crypto/lhash/lhash.c b/crypto/lhash/lhash.c index 21757e47cc..a652631e10 100644 --- a/crypto/lhash/lhash.c +++ b/crypto/lhash/lhash.c @@ -344,18 +344,37 @@ unsigned long OPENSSL_LH_strhash(const char *c) return (ret >> 16) ^ ret; } +/* + * Case insensitive string hashing. + * + * The lower/upper case bit is masked out (forcing all letters to be capitals). + * The major side effect on non-alpha characters is mapping the symbols and + * digits into the control character range (which should be harmless). + * The duplication (with respect to the hash value) of printable characters + * are that '`', '{', '|', '}' and '~' map to '@', '[', '\', ']' and '^' + * respectively (which seems tolerable). + * + * For EBCDIC, the alpha mapping is to lower case, most symbols go to control + * characters. The only duplication is '0' mapping to '^', which is better + * than for ASCII. + */ unsigned long ossl_lh_strcasehash(const char *c) { unsigned long ret = 0; long n; unsigned long v; int r; +#if defined(CHARSET_EBCDIC) && !defined(CHARSET_EBCDIC_TEST) + const long int case_adjust = ~0x40; +#else + const long int case_adjust = ~0x20; +#endif if (c == NULL || *c == '\0') return ret; for (n = 0x100; *c != '\0'; n += 0x100) { - v = n | ossl_tolower(*c); + v = n | (case_adjust & *c); r = (int)((v >> 2) ^ v) & 0x0f; /* cast to uint64_t to avoid 32 bit shift of 32 bit value */ ret = (ret << r) | (unsigned long)((uint64_t)ret >> (32 - r)); |