string_split.cc revision 4a5e2dc747d50c653511c68ccb2cfbfb740bd5a7 
1// Copyright (c) 2010 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#include "base/string_split.h"
6
7#include "base/logging.h"
8#include "base/string_util.h"
9#include "base/third_party/icu/icu_utf.h"
10#include "base/utf_string_conversions.h"
11
12namespace base {
13
14template<typename STR>
15static void SplitStringT(const STR& str,
16                         const typename STR::value_type s,
17                         bool trim_whitespace,
18                         std::vector<STR>* r) {
19  size_t last = 0;
20  size_t i;
21  size_t c = str.size();
22  for (i = 0; i <= c; ++i) {
23    if (i == c || str[i] == s) {
24      size_t len = i - last;
25      STR tmp = str.substr(last, len);
26      if (trim_whitespace) {
27        STR t_tmp;
28        TrimWhitespace(tmp, TRIM_ALL, &t_tmp);
29        r->push_back(t_tmp);
30      } else {
31        r->push_back(tmp);
32      }
33      last = i + 1;
34    }
35  }
36}
37
38void SplitString(const std::wstring& str,
39                 wchar_t c,
40                 std::vector<std::wstring>* r) {
41  SplitStringT(str, c, true, r);
42}
43
44#if !defined(WCHAR_T_IS_UTF16)
45void SplitString(const string16& str,
46                 char16 c,
47                 std::vector<string16>* r) {
48  DCHECK(CBU16_IS_SINGLE(c));
49  SplitStringT(str, c, true, r);
50}
51#endif
52
53void SplitString(const std::string& str,
54                 char c,
55                 std::vector<std::string>* r) {
56  DCHECK(c >= 0 && c < 0x7F);
57  SplitStringT(str, c, true, r);
58}
59
60bool SplitStringIntoKeyValues(
61    const std::string& line,
62    char key_value_delimiter,
63    std::string* key, std::vector<std::string>* values) {
64  key->clear();
65  values->clear();
66
67  // Find the key string.
68  size_t end_key_pos = line.find_first_of(key_value_delimiter);
69  if (end_key_pos == std::string::npos) {
70    DVLOG(1) << "cannot parse key from line: " << line;
71    return false;    // no key
72  }
73  key->assign(line, 0, end_key_pos);
74
75  // Find the values string.
76  std::string remains(line, end_key_pos, line.size() - end_key_pos);
77  size_t begin_values_pos = remains.find_first_not_of(key_value_delimiter);
78  if (begin_values_pos == std::string::npos) {
79    DVLOG(1) << "cannot parse value from line: " << line;
80    return false;   // no value
81  }
82  std::string values_string(remains, begin_values_pos,
83                            remains.size() - begin_values_pos);
84
85  // Construct the values vector.
86  values->push_back(values_string);
87  return true;
88}
89
90bool SplitStringIntoKeyValuePairs(
91    const std::string& line,
92    char key_value_delimiter,
93    char key_value_pair_delimiter,
94    std::vector<std::pair<std::string, std::string> >* kv_pairs) {
95  kv_pairs->clear();
96
97  std::vector<std::string> pairs;
98  SplitString(line, key_value_pair_delimiter, &pairs);
99
100  bool success = true;
101  for (size_t i = 0; i < pairs.size(); ++i) {
102    // Empty pair. SplitStringIntoKeyValues is more strict about an empty pair
103    // line, so continue with the next pair.
104    if (pairs[i].empty())
105      continue;
106
107    std::string key;
108    std::vector<std::string> value;
109    if (!SplitStringIntoKeyValues(pairs[i],
110                                  key_value_delimiter,
111                                  &key, &value)) {
112      // Don't return here, to allow for keys without associated
113      // values; just record that our split failed.
114      success = false;
115    }
116    DCHECK_LE(value.size(), 1U);
117    kv_pairs->push_back(make_pair(key, value.empty()? "" : value[0]));
118  }
119  return success;
120}
121
122template <typename STR>
123static void SplitStringUsingSubstrT(const STR& str,
124                                    const STR& s,
125                                    std::vector<STR>* r) {
126  typename STR::size_type begin_index = 0;
127  while (true) {
128    const typename STR::size_type end_index = str.find(s, begin_index);
129    if (end_index == STR::npos) {
130      const STR term = str.substr(begin_index);
131      STR tmp;
132      TrimWhitespace(term, TRIM_ALL, &tmp);
133      r->push_back(tmp);
134      return;
135    }
136    const STR term = str.substr(begin_index, end_index - begin_index);
137    STR tmp;
138    TrimWhitespace(term, TRIM_ALL, &tmp);
139    r->push_back(tmp);
140    begin_index = end_index + s.size();
141  }
142}
143
144void SplitStringUsingSubstr(const string16& str,
145                            const string16& s,
146                            std::vector<string16>* r) {
147  SplitStringUsingSubstrT(str, s, r);
148}
149
150void SplitStringUsingSubstr(const std::string& str,
151                            const std::string& s,
152                            std::vector<std::string>* r) {
153  SplitStringUsingSubstrT(str, s, r);
154}
155
156void SplitStringDontTrim(const string16& str,
157                         char16 c,
158                         std::vector<string16>* r) {
159  DCHECK(CBU16_IS_SINGLE(c));
160  SplitStringT(str, c, false, r);
161}
162
163void SplitStringDontTrim(const std::string& str,
164                         char c,
165                         std::vector<std::string>* r) {
166  DCHECK(IsStringUTF8(str));
167  DCHECK(c >= 0 && c < 0x7F);
168  SplitStringT(str, c, false, r);
169}
170
171template<typename STR>
172void SplitStringAlongWhitespaceT(const STR& str, std::vector<STR>* result) {
173  const size_t length = str.length();
174  if (!length)
175    return;
176
177  bool last_was_ws = false;
178  size_t last_non_ws_start = 0;
179  for (size_t i = 0; i < length; ++i) {
180    switch (str[i]) {
181      // HTML 5 defines whitespace as: space, tab, LF, line tab, FF, or CR.
182      case L' ':
183      case L'\t':
184      case L'\xA':
185      case L'\xB':
186      case L'\xC':
187      case L'\xD':
188        if (!last_was_ws) {
189          if (i > 0) {
190            result->push_back(
191                str.substr(last_non_ws_start, i - last_non_ws_start));
192          }
193          last_was_ws = true;
194        }
195        break;
196
197      default:  // Not a space character.
198        if (last_was_ws) {
199          last_was_ws = false;
200          last_non_ws_start = i;
201        }
202        break;
203    }
204  }
205  if (!last_was_ws) {
206    result->push_back(
207        str.substr(last_non_ws_start, length - last_non_ws_start));
208  }
209}
210
211void SplitStringAlongWhitespace(const std::wstring& str,
212                                std::vector<std::wstring>* result) {
213  SplitStringAlongWhitespaceT(str, result);
214}
215
216#if !defined(WCHAR_T_IS_UTF16)
217void SplitStringAlongWhitespace(const string16& str,
218                                std::vector<string16>* result) {
219  SplitStringAlongWhitespaceT(str, result);
220}
221#endif
222
223void SplitStringAlongWhitespace(const std::string& str,
224                                std::vector<std::string>* result) {
225  SplitStringAlongWhitespaceT(str, result);
226}
227
228}  // namespace base
229