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Posted to commits@apr.apache.org by yl...@apache.org on 2022/01/15 23:22:33 UTC
svn commit: r1897103 - in /apr/apr/branches/1.8.x: ./ strings/ strings/apr_cstr.c
Author: ylavic
Date: Sat Jan 15 23:22:33 2022
New Revision: 1897103
URL: http://svn.apache.org/viewvc?rev=1897103&view=rev
Log:
apr_cstr: Improve apr_cstr_casecmp() and apr_cstr_casecmpn() performances.
The new versions [1] compile to a shorter/faster assembly than the previous
ones [2], no functionnal change.
[1] apr_cstr_casecmp() after this commit:
Dump of assembler code for function apr_cstr_casecmp:
0x0000000000049fc0 <+0>: movzbl (%rdi),%eax
0x0000000000049fc3 <+3>: movzbl (%rsi),%edx
0x0000000000049fc6 <+6>: lea 0x3d573(%rip),%r8 # 0x87540 <ucharmap>
0x0000000000049fcd <+13>: movzbl (%r8,%rax,1),%eax
0x0000000000049fd2 <+18>: movzbl (%r8,%rdx,1),%ecx
0x0000000000049fd7 <+23>: cmp %ecx,%eax
0x0000000000049fd9 <+25>: jne 0x49ffe <apr_cstr_casecmp+62>
0x0000000000049fdb <+27>: xor %edx,%edx
0x0000000000049fdd <+29>: jmp 0x49ffa <apr_cstr_casecmp+58>
0x0000000000049fdf <+31>: nop
0x0000000000049fe0 <+32>: add $0x1,%rdx
0x0000000000049fe4 <+36>: movzbl (%rdi,%rdx,1),%eax
0x0000000000049fe8 <+40>: movzbl (%rsi,%rdx,1),%ecx
0x0000000000049fec <+44>: movzbl (%r8,%rax,1),%eax
0x0000000000049ff1 <+49>: movzbl (%r8,%rcx,1),%ecx
0x0000000000049ff6 <+54>: cmp %ecx,%eax
0x0000000000049ff8 <+56>: jne 0x49ffe <apr_cstr_casecmp+62>
0x0000000000049ffa <+58>: test %eax,%eax
0x0000000000049ffc <+60>: jne 0x49fe0 <apr_cstr_casecmp+32>
0x0000000000049ffe <+62>: sub %ecx,%eax
0x000000000004a000 <+64>: ret
End of assembler dump.
[2] apr_cstr_casecmp() before this commit:
Dump of assembler code for function apr_cstr_casecmp:
0x000000000004a000 <+0>: movzbl (%rdi),%eax
0x000000000004a003 <+3>: movzbl (%rsi),%edx
0x000000000004a006 <+6>: lea 0x3d533(%rip),%r8 # 0x87540 <ucharmap>
0x000000000004a00d <+13>: mov %rdi,%r9
0x000000000004a010 <+16>: mov %rax,%rcx
0x000000000004a013 <+19>: movswl (%r8,%rdx,2),%edx
0x000000000004a018 <+24>: movswl (%r8,%rax,2),%eax
0x000000000004a01d <+29>: sub %edx,%eax
0x000000000004a01f <+31>: jne 0x4a052 <apr_cstr_casecmp+82>
0x000000000004a021 <+33>: mov $0x1,%edx
0x000000000004a026 <+38>: test %ecx,%ecx
0x000000000004a028 <+40>: je 0x4a052 <apr_cstr_casecmp+82>
0x000000000004a02a <+42>: nopw 0x0(%rax,%rax,1)
0x000000000004a030 <+48>: movzbl (%r9,%rdx,1),%eax
0x000000000004a035 <+53>: movzbl (%rsi,%rdx,1),%ecx
0x000000000004a039 <+57>: add $0x1,%rdx
0x000000000004a03d <+61>: mov %rax,%rdi
0x000000000004a040 <+64>: movswl (%r8,%rcx,2),%ecx
0x000000000004a045 <+69>: movswl (%r8,%rax,2),%eax
0x000000000004a04a <+74>: sub %ecx,%eax
0x000000000004a04c <+76>: jne 0x4a052 <apr_cstr_casecmp+82>
0x000000000004a04e <+78>: test %edi,%edi
0x000000000004a050 <+80>: jne 0x4a030 <apr_cstr_casecmp+48>
0x000000000004a052 <+82>: ret
End of assembler dump.
Merge r1897102 from trunk.
Submitted by: ylavic
Modified:
apr/apr/branches/1.8.x/ (props changed)
apr/apr/branches/1.8.x/strings/ (props changed)
apr/apr/branches/1.8.x/strings/apr_cstr.c
Propchange: apr/apr/branches/1.8.x/
------------------------------------------------------------------------------
Merged /apr/apr/trunk:r1897102
Propchange: apr/apr/branches/1.8.x/strings/
------------------------------------------------------------------------------
Merged /apr/apr/trunk/strings:r1897102
Modified: apr/apr/branches/1.8.x/strings/apr_cstr.c
URL: http://svn.apache.org/viewvc/apr/apr/branches/1.8.x/strings/apr_cstr.c?rev=1897103&r1=1897102&r2=1897103&view=diff
==============================================================================
--- apr/apr/branches/1.8.x/strings/apr_cstr.c (original)
+++ apr/apr/branches/1.8.x/strings/apr_cstr.c Sat Jan 15 23:22:33 2022
@@ -197,7 +197,7 @@ APR_DECLARE(char *) apr_cstr_join(const
* octets (such as extended latin alphabetics) are never case-folded.
* NOTE: Other than Alpha A-Z/a-z, each code point is unique!
*/
-static const short ucharmap[] = {
+static const unsigned char ucharmap[256] = {
0x0, 0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7,
0x8, 0x9, 0xa, 0xb, 0xc, 0xd, 0xe, 0xf,
0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
@@ -244,7 +244,7 @@ static const short ucharmap[] = {
*
* NOTE: Other than Alpha A-Z/a-z, each code point is unique!
*/
-static const short ucharmap[] = {
+static const unsigned char ucharmap[256] = {
0x00, 0x01, 0x02, 0x03, 0x9C, 0x09, 0x86, 0x7F,
0x97, 0x8D, 0x8E, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F,
0x10, 0x11, 0x12, 0x13, 0x9D, 0x85, 0x08, 0x87,
@@ -282,35 +282,25 @@ static const short ucharmap[] = {
APR_DECLARE(int) apr_cstr_casecmp(const char *s1, const char *s2)
{
- const unsigned char *str1 = (const unsigned char *)s1;
- const unsigned char *str2 = (const unsigned char *)s2;
- for (;;)
- {
- const int c1 = (int)(*str1);
- const int c2 = (int)(*str2);
- const int cmp = ucharmap[c1] - ucharmap[c2];
- /* Not necessary to test for !c2, this is caught by cmp */
- if (cmp || !c1)
- return cmp;
- str1++;
- str2++;
+ 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;
}
}
APR_DECLARE(int) apr_cstr_casecmpn(const char *s1, const char *s2, apr_size_t n)
{
- const unsigned char *str1 = (const unsigned char *)s1;
- const unsigned char *str2 = (const unsigned char *)s2;
- while (n--)
- {
- const int c1 = (int)(*str1);
- const int c2 = (int)(*str2);
- const int cmp = ucharmap[c1] - ucharmap[c2];
- /* Not necessary to test for !c2, this is caught by cmp */
- if (cmp || !c1)
- return cmp;
- str1++;
- str2++;
+ 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;
}
return 0;
}