stringpiece.cc revision 5821806d5e7f356e8fa4b058a389a808ea183019 
1// Copyright 2004 The RE2 Authors.  All Rights Reserved.
2// Use of this source code is governed by a BSD-style
3// license that can be found in the LICENSE file.
4
5#include "re2/stringpiece.h"
6#include "util/util.h"
7
8using re2::StringPiece;
9
10std::ostream& operator<<(std::ostream& o, const StringPiece& piece) {
11  o.write(piece.data(), piece.size());
12  return o;
13}
14
15bool StringPiece::_equal(const StringPiece& x, const StringPiece& y) {
16  int len = x.size();
17  if (len != y.size()) {
18    return false;
19  }
20  const char* p = x.data();
21  const char* p2 = y.data();
22  // Test last byte in case strings share large common prefix
23  if ((len > 0) && (p[len-1] != p2[len-1])) return false;
24  const char* p_limit = p + len;
25  for (; p < p_limit; p++, p2++) {
26    if (*p != *p2)
27      return false;
28  }
29  return true;
30}
31
32void StringPiece::CopyToString(string* target) const {
33  target->assign(ptr_, length_);
34}
35
36int StringPiece::copy(char* buf, size_type n, size_type pos) const {
37  int ret = min(length_ - pos, n);
38  memcpy(buf, ptr_ + pos, ret);
39  return ret;
40}
41
42int StringPiece::find(const StringPiece& s, size_type pos) const {
43  if (length_ < 0 || pos > static_cast<size_type>(length_))
44    return npos;
45
46  const char* result = std::search(ptr_ + pos, ptr_ + length_,
47                                   s.ptr_, s.ptr_ + s.length_);
48  const size_type xpos = result - ptr_;
49  return xpos + s.length_ <= length_ ? xpos : npos;
50}
51
52int StringPiece::find(char c, size_type pos) const {
53  if (length_ <= 0 || pos >= static_cast<size_type>(length_)) {
54    return npos;
55  }
56  const char* result = std::find(ptr_ + pos, ptr_ + length_, c);
57  return result != ptr_ + length_ ? result - ptr_ : npos;
58}
59
60int StringPiece::rfind(const StringPiece& s, size_type pos) const {
61  if (length_ < s.length_) return npos;
62  const size_t ulen = length_;
63  if (s.length_ == 0) return min(ulen, pos);
64
65  const char* last = ptr_ + min(ulen - s.length_, pos) + s.length_;
66  const char* result = std::find_end(ptr_, last, s.ptr_, s.ptr_ + s.length_);
67  return result != last ? result - ptr_ : npos;
68}
69
70int StringPiece::rfind(char c, size_type pos) const {
71  if (length_ <= 0) return npos;
72  for (int i = min(pos, static_cast<size_type>(length_ - 1));
73       i >= 0; --i) {
74    if (ptr_[i] == c) {
75      return i;
76    }
77  }
78  return npos;
79}
80
81StringPiece StringPiece::substr(size_type pos, size_type n) const {
82  if (pos > length_) pos = length_;
83  if (n > length_ - pos) n = length_ - pos;
84  return StringPiece(ptr_ + pos, n);
85}
86
87const StringPiece::size_type StringPiece::npos = size_type(-1);
88