/src/icu/icu4c/source/common/stringpiece.cpp
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1 | | // © 2016 and later: Unicode, Inc. and others. |
2 | | // License & terms of use: http://www.unicode.org/copyright.html |
3 | | // Copyright (C) 2009-2013, International Business Machines |
4 | | // Corporation and others. All Rights Reserved. |
5 | | // |
6 | | // Copyright 2004 and onwards Google Inc. |
7 | | // |
8 | | // Author: wilsonh@google.com (Wilson Hsieh) |
9 | | // |
10 | | |
11 | | #include "unicode/utypes.h" |
12 | | #include "unicode/stringpiece.h" |
13 | | #include "cstring.h" |
14 | | #include "cmemory.h" |
15 | | |
16 | | U_NAMESPACE_BEGIN |
17 | | |
18 | | StringPiece::StringPiece(const char* str) |
19 | 0 | : ptr_(str), length_((str == nullptr) ? 0 : static_cast<int32_t>(uprv_strlen(str))) { } |
20 | | |
21 | 0 | StringPiece::StringPiece(const StringPiece& x, int32_t pos) { |
22 | 0 | if (pos < 0) { |
23 | 0 | pos = 0; |
24 | 0 | } else if (pos > x.length_) { |
25 | 0 | pos = x.length_; |
26 | 0 | } |
27 | 0 | ptr_ = x.ptr_ + pos; |
28 | 0 | length_ = x.length_ - pos; |
29 | 0 | } |
30 | | |
31 | 0 | StringPiece::StringPiece(const StringPiece& x, int32_t pos, int32_t len) { |
32 | 0 | if (pos < 0) { |
33 | 0 | pos = 0; |
34 | 0 | } else if (pos > x.length_) { |
35 | 0 | pos = x.length_; |
36 | 0 | } |
37 | 0 | if (len < 0) { |
38 | 0 | len = 0; |
39 | 0 | } else if (len > x.length_ - pos) { |
40 | 0 | len = x.length_ - pos; |
41 | 0 | } |
42 | 0 | ptr_ = x.ptr_ + pos; |
43 | 0 | length_ = len; |
44 | 0 | } |
45 | | |
46 | 0 | void StringPiece::set(const char* str) { |
47 | 0 | ptr_ = str; |
48 | 0 | if (str != nullptr) |
49 | 0 | length_ = static_cast<int32_t>(uprv_strlen(str)); |
50 | 0 | else |
51 | 0 | length_ = 0; |
52 | 0 | } |
53 | | |
54 | 0 | int32_t StringPiece::find(StringPiece needle, int32_t offset) { |
55 | 0 | if (length() == 0 && needle.length() == 0) { |
56 | 0 | return 0; |
57 | 0 | } |
58 | | // TODO: Improve to be better than O(N^2)? |
59 | 0 | for (int32_t i = offset; i < length(); i++) { |
60 | 0 | int32_t j = 0; |
61 | 0 | for (; j < needle.length(); i++, j++) { |
62 | 0 | if (data()[i] != needle.data()[j]) { |
63 | 0 | i -= j; |
64 | 0 | goto outer_end; |
65 | 0 | } |
66 | 0 | } |
67 | 0 | return i - j; |
68 | 0 | outer_end: void(); |
69 | 0 | } |
70 | 0 | return -1; |
71 | 0 | } |
72 | | |
73 | 0 | int32_t StringPiece::compare(StringPiece other) { |
74 | 0 | int32_t i = 0; |
75 | 0 | for (; i < length(); i++) { |
76 | 0 | if (i == other.length()) { |
77 | | // this is longer |
78 | 0 | return 1; |
79 | 0 | } |
80 | 0 | char a = data()[i]; |
81 | 0 | char b = other.data()[i]; |
82 | 0 | if (a < b) { |
83 | 0 | return -1; |
84 | 0 | } else if (a > b) { |
85 | 0 | return 1; |
86 | 0 | } |
87 | 0 | } |
88 | 0 | if (i < other.length()) { |
89 | | // other is longer |
90 | 0 | return -1; |
91 | 0 | } |
92 | 0 | return 0; |
93 | 0 | } |
94 | | |
95 | | U_EXPORT UBool U_EXPORT2 |
96 | 0 | operator==(const StringPiece& x, const StringPiece& y) { |
97 | 0 | int32_t len = x.size(); |
98 | 0 | if (len != y.size()) { |
99 | 0 | return false; |
100 | 0 | } |
101 | 0 | if (len == 0) { |
102 | 0 | return true; |
103 | 0 | } |
104 | 0 | const char* p = x.data(); |
105 | 0 | const char* p2 = y.data(); |
106 | | // Test last byte in case strings share large common prefix |
107 | 0 | --len; |
108 | 0 | if (p[len] != p2[len]) return false; |
109 | | // At this point we can, but don't have to, ignore the last byte. |
110 | 0 | return uprv_memcmp(p, p2, len) == 0; |
111 | 0 | } |
112 | | |
113 | | |
114 | | const int32_t StringPiece::npos = 0x7fffffff; |
115 | | |
116 | | U_NAMESPACE_END |