From 444cc405e1ad5afea49c9757be5a2c31c81804b6 Mon Sep 17 00:00:00 2001 From: "Paul R. Eggert" Date: Mon, 12 Jul 2010 10:58:35 -0700 Subject: [PATCH] memcoll: clarify sizes versus lengths, document better, and tweak perf * lib/memcoll.c (strcoll_loop, memcoll0): Improve quality of descriptive comments. Name variables consistently as to whether they are lengths (which do not include terminating null) versus sizes (which do). * lib/xmemcoll.c (xmemcoll0): Likewise. * lib/memcoll.c (strcoll_loop): Tweak the way that the diff is returned when s1size == 0; this is easier to compile and saves about 17% of memcoll's code space on x86-64 with GCC 4.1.2. --- ChangeLog | 12 ++++++++++++ lib/memcoll.c | 52 +++++++++++++++++++++++--------------------------- lib/xmemcoll.c | 6 ++++-- 3 files changed, 40 insertions(+), 30 deletions(-) diff --git a/ChangeLog b/ChangeLog index 0034cadcfc..886f5bde4d 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,15 @@ +2010-07-12 Paul R. Eggert + + memcoll: clarify sizes versus lengths, document better, and tweak perf + * lib/memcoll.c (strcoll_loop, memcoll0): + Improve quality of descriptive comments. Name variables + consistently as to whether they are lengths (which do not include + terminating null) versus sizes (which do). + * lib/xmemcoll.c (xmemcoll0): Likewise. + * lib/memcoll.c (strcoll_loop): Tweak the way that the diff is + returned when s1size == 0; this is easier to compile and saves + about 17% of memcoll's code space on x86-64 with GCC 4.1.2. + 2010-07-12 Bruno Haible Tests for module '_Exit'. diff --git a/lib/memcoll.c b/lib/memcoll.c index 580f81d02b..39b383c742 100644 --- a/lib/memcoll.c +++ b/lib/memcoll.c @@ -26,11 +26,13 @@ #include #include -/* Ensure strcoll operates on the entire input strings, in case they contain - NUL bytes. */ - +/* Compare S1 (with size S1SIZE) and S2 (with length S2SIZE) according + to the LC_COLLATE locale. S1 and S2 are both blocks of memory with + nonzero sizes, and the last byte in each block must be a null byte. + Set errno to an error number if there is an error, and to zero + otherwise. */ static inline int -strcoll_loop (char const *s1, size_t s1len, const char *s2, size_t s2len) +strcoll_loop (char const *s1, size_t s1size, char const *s2, size_t s2size) { int diff; @@ -43,20 +45,13 @@ strcoll_loop (char const *s1, size_t s1len, const char *s2, size_t s2len) size_t size2 = strlen (s2) + 1; s1 += size1; s2 += size2; - s1len -= size1; - s2len -= size2; - - if (s1len == 0) - { - if (s2len != 0) - diff = -1; - break; - } - else if (s2len == 0) - { - diff = 1; - break; - } + s1size -= size1; + s2size -= size2; + + if (s1size == 0) + return - (s2size != 0); + if (s2size == 0) + return 1; } return diff; @@ -86,30 +81,31 @@ memcoll (char *s1, size_t s1len, char *s2, size_t s2len) char n1 = s1[s1len]; char n2 = s2[s2len]; - s1[s1len++] = '\0'; - s2[s2len++] = '\0'; + s1[s1len] = '\0'; + s2[s2len] = '\0'; - diff = strcoll_loop (s1, s1len, s2, s2len); + diff = strcoll_loop (s1, s1len + 1, s2, s2len + 1); - s1[s1len - 1] = n1; - s2[s2len - 1] = n2; + s1[s1len] = n1; + s2[s2len] = n2; } return diff; } -/* Compare S1 (with length S1LEN) and S2 (with length S2LEN) according - to the LC_COLLATE locale. S1 and S2 must both end in a null byte. +/* Compare S1 (with size S1SIZE) and S2 (with length S2SIZE) according + to the LC_COLLATE locale. S1 and S2 are both blocks of memory with + nonzero sizes, and the last byte in each block must be a null byte. Set errno to an error number if there is an error, and to zero otherwise. */ int -memcoll0 (char const *s1, size_t s1len, const char *s2, size_t s2len) +memcoll0 (char const *s1, size_t s1size, char const *s2, size_t s2size) { - if (s1len == s2len && memcmp (s1, s2, s1len) == 0) + if (s1size == s2size && memcmp (s1, s2, s1size) == 0) { errno = 0; return 0; } else - return strcoll_loop (s1, s1len, s2, s2len); + return strcoll_loop (s1, s1size, s2, s2size); } diff --git a/lib/xmemcoll.c b/lib/xmemcoll.c index 7f8c894b05..d2ddc33d08 100644 --- a/lib/xmemcoll.c +++ b/lib/xmemcoll.c @@ -60,8 +60,10 @@ xmemcoll (char *s1, size_t s1len, char *s2, size_t s2len) return diff; } -/* Like xmemcoll, but S1 and S2 are known to be NUL delimited, thus - no modifications to S1 and S2 are needed. */ +/* Compare S1 (with size S1SIZE) and S2 (with length S2SIZE) according + to the LC_COLLATE locale. S1 and S2 are both blocks of memory with + nonzero sizes, and the last byte in each block must be a null byte. + Report an error and exit if there is an error. */ int xmemcoll0 (char const *s1, size_t s1len, char const *s2, size_t s2len) -- 2.30.2