1 /* Copyright (c) 2013, 2021, Oracle and/or its affiliates.
2
3 This program is free software; you can redistribute it and/or modify
4 it under the terms of the GNU General Public License, version 2.0,
5 as published by the Free Software Foundation.
6
7 This program is also distributed with certain software (including
8 but not limited to OpenSSL) that is licensed under separate terms,
9 as designated in a particular file or component or in included license
10 documentation. The authors of MySQL hereby grant you an additional
11 permission to link the program and your derivative works with the
12 separately licensed software that they have included with MySQL.
13
14 This program is distributed in the hope that it will be useful,
15 but WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 GNU General Public License, version 2.0, for more details.
18
19 You should have received a copy of the GNU General Public License
20 along with this program; if not, write to the Free Software
21 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */
22
23 #include "skip_trailing.h"
24
25 namespace skip_trailing_space_unittest {
26
27 /* SPACE_INT is a word that contains only spaces */
28 #if SIZEOF_INT == 4
29 static const unsigned SPACE_INT= 0x20202020U;
30 #elif SIZEOF_INT == 8
31 static const unsigned SPACE_INT= 0x2020202020202020ULL;
32 #else
33 #error define the appropriate constant for a word full of spaces
34 #endif
35
36 // A copy of the original version of skip_trailing_space
skip_trailing_orig(const uchar * ptr,size_t len)37 const uchar *skip_trailing_orig(const uchar *ptr,size_t len)
38 {
39 const uchar *end= ptr + len;
40
41 if (len > 20)
42 {
43 const uchar *end_words= (const uchar *)(intptr)
44 (((ulonglong)(intptr)end) / SIZEOF_INT * SIZEOF_INT);
45 const uchar *start_words= (const uchar *)(intptr)
46 ((((ulonglong)(intptr)ptr) + SIZEOF_INT - 1) / SIZEOF_INT * SIZEOF_INT);
47
48 assert(((ulonglong)(intptr)ptr) >= SIZEOF_INT);
49 if (end_words > ptr)
50 {
51 while (end > end_words && end[-1] == 0x20)
52 end--;
53 if (end[-1] == 0x20 && start_words < end_words)
54 while (end > start_words && ((unsigned *)end)[-1] == SPACE_INT)
55 end -= SIZEOF_INT;
56 }
57 }
58 while (end > ptr && end[-1] == 0x20)
59 end--;
60 return (end);
61 }
62
63
64 // Read 8 bytes at a time, ignoring alignment.
65 // We use uint8korr which is fast on all platforms, except sparc.
skip_trailing_unalgn(const uchar * ptr,size_t len)66 const uchar *skip_trailing_unalgn(const uchar *ptr, size_t len)
67 {
68 const uchar *end= ptr + len;
69 while (end - ptr >= 8)
70 {
71 if (uint8korr(end-8) != 0x2020202020202020ULL)
72 break;
73 end-= 8;
74 }
75 while (end > ptr && end[-1] == 0x20)
76 end--;
77 return (end);
78 }
79
80
81 // Same as the original, except we skip a test which is always true.
skip_trailing_4byte(const uchar * ptr,size_t len)82 const uchar *skip_trailing_4byte(const uchar *ptr, size_t len)
83 {
84 const uchar *end= ptr + len;
85
86 if (len > 20)
87 {
88 const uchar *end_words= (const uchar *)(intptr)
89 (((ulonglong)(intptr)end) / SIZEOF_INT * SIZEOF_INT);
90 const uchar *start_words= (const uchar *)(intptr)
91 ((((ulonglong)(intptr)ptr) + SIZEOF_INT - 1) / SIZEOF_INT * SIZEOF_INT);
92
93 assert(end_words > ptr);
94 {
95 while (end > end_words && end[-1] == 0x20)
96 end--;
97 if (end[-1] == 0x20 && start_words < end_words)
98 while (end > start_words && ((unsigned *)end)[-1] == SPACE_INT)
99 end -= SIZEOF_INT;
100 }
101 }
102 while (end > ptr && end[-1] == 0x20)
103 end--;
104 return (end);
105 }
106
107
108 // Same as skip_trailing_4byte, except we read 8 bytes at a time (aligned).
skip_trailing_8byte(const uchar * ptr,size_t len)109 const uchar *skip_trailing_8byte(const uchar *ptr, size_t len)
110 {
111 const uchar *end= ptr + len;
112
113 if (len > 20)
114 {
115 const uchar *end_words= (const uchar *)(longlong)
116 (((ulonglong)(longlong)end) / 8 * 8);
117 const uchar *start_words= (const uchar *)(longlong)
118 ((((ulonglong)(longlong)ptr) + 8 - 1) / 8 * 8);
119
120 assert(end_words > ptr);
121 {
122 while (end > end_words && end[-1] == 0x20)
123 end--;
124 if (end[-1] == 0x20 && start_words < end_words)
125 while (end > start_words &&
126 ((ulonglong *)end)[-1] == 0x2020202020202020ULL)
127 end -= 8;
128 }
129 }
130 while (end > ptr && end[-1] == 0x20)
131 end--;
132 return (end);
133 }
134
135 }
136