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author | ylavic <ylavic@13f79535-47bb-0310-9956-ffa450edef68> | 2022-01-16 13:18:34 +0000 |
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committer | ylavic <ylavic@13f79535-47bb-0310-9956-ffa450edef68> | 2022-01-16 13:18:34 +0000 |
commit | dfec7833867bb71596600e42b456a8d8904512ec (patch) | |
tree | ee620f2fa9b92ea8191e5172a3cc1e84f9e7dc06 | |
parent | a5e5af946ca447b7dfe6062ea2fb8f9de4159ff5 (diff) | |
download | libapr-dfec7833867bb71596600e42b456a8d8904512ec.tar.gz |
apr_cstr: Follow up to r1897102: Yet better apr_cstr_casecmp[n]().
This ones have a shorter prologue and epilogue (-O2 still).
Dump of assembler code for function apr_cstr_casecmp:
0x0000000000049fd0 <+0>: xor %edx,%edx
0x0000000000049fd2 <+2>: lea 0x3d567(%rip),%r8 # 0x87540 <ucharmap>
0x0000000000049fd9 <+9>: nopl 0x0(%rax)
0x0000000000049fe0 <+16>: movzbl (%rsi,%rdx,1),%eax
0x0000000000049fe4 <+20>: movzbl (%r8,%rax,1),%ecx
0x0000000000049fe9 <+25>: movzbl (%rdi,%rdx,1),%eax
0x0000000000049fed <+29>: add $0x1,%rdx
0x0000000000049ff1 <+33>: movzbl (%r8,%rax,1),%eax
0x0000000000049ff6 <+38>: sub %ecx,%eax
0x0000000000049ff8 <+40>: jne 0x49ffe <apr_cstr_casecmp+46>
0x0000000000049ffa <+42>: test %ecx,%ecx
0x0000000000049ffc <+44>: jne 0x49fe0 <apr_cstr_casecmp+16>
0x0000000000049ffe <+46>: ret
End of assembler dump.
Merge r1897121 from trunk.
Submitted by: ylavic
git-svn-id: https://svn.apache.org/repos/asf/apr/apr/branches/1.8.x@1897122 13f79535-47bb-0310-9956-ffa450edef68
-rw-r--r-- | strings/apr_cstr.c | 30 |
1 files changed, 16 insertions, 14 deletions
diff --git a/strings/apr_cstr.c b/strings/apr_cstr.c index c211c46dd..fbd801986 100644 --- a/strings/apr_cstr.c +++ b/strings/apr_cstr.c @@ -282,25 +282,27 @@ static const unsigned char ucharmap[256] = { APR_DECLARE(int) apr_cstr_casecmp(const char *s1, const char *s2) { - apr_size_t i = 0; - for (;; ++i) { - const int c1 = ucharmap[(unsigned char)s1[i]]; - const int c2 = ucharmap[(unsigned char)s2[i]]; - /* Not necessary to test for !c2, this is caught by c1 != c2 */ - if (c1 != c2 || !c1) - return c1 - c2; + const unsigned char *u1 = (const unsigned char *)s1; + const unsigned char *u2 = (const unsigned char *)s2; + for (;;) { + const int c2 = ucharmap[*u2++]; + const int cmp = (int)ucharmap[*u1++] - c2; + /* Not necessary to test for !c1, this is caught by cmp */ + if (cmp || !c2) + return cmp; } } APR_DECLARE(int) apr_cstr_casecmpn(const char *s1, const char *s2, apr_size_t n) { - apr_size_t i = 0; - for (; i < n; ++i) { - const int c1 = ucharmap[(unsigned char)s1[i]]; - const int c2 = ucharmap[(unsigned char)s2[i]]; - /* Not necessary to test for !c2, this is caught by c1 != c2 */ - if (c1 != c2 || !c1) - return c1 - c2; + const unsigned char *u1 = (const unsigned char *)s1; + const unsigned char *u2 = (const unsigned char *)s2; + while (n--) { + const int c2 = ucharmap[*u2++]; + const int cmp = (int)ucharmap[*u1++] - c2; + /* Not necessary to test for !c1, this is caught by cmp */ + if (cmp || !c2) + return cmp; } return 0; } |