base/strings/string_split.cc

   1 // Copyright (c) 2012 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/strings/string_split.h"
   6
   7 #include "base/logging.h"
   8 #include "base/strings/string_util.h"
   9 #include "base/strings/utf_string_conversions.h"
  10 #include "base/third_party/icu/icu_utf.h"
  11
  12 namespace base {
  13
  14 namespace {
  15
  16 template <typename STR>
  17 void SplitStringT(const STR& str,
  18                   const typename STR::value_type s,
  19                   bool trim_whitespace,
  20                   std::vector<STR>* r) {
  21   r->clear();
  22   size_t last = 0;
  23   size_t c = str.size();
  24   for (size_t i = 0; i <= c; ++i) {
  25     if (i == c || str[i] == s) {
  26       STR tmp(str, last, i - last);
  27       if (trim_whitespace)
  28         TrimWhitespace(tmp, TRIM_ALL, &tmp);
  29       // Avoid converting an empty or all-whitespace source string into a vector
  30       // of one empty string.
  31       if (i != c || !r->empty() || !tmp.empty())
  32         r->push_back(tmp);
  33       last = i + 1;
  34     }
  35   }
  36 }
  37
  38 bool SplitStringIntoKeyValue(const std::string& line,
  39                              char key_value_delimiter,
  40                              std::string* key,
  41                              std::string* value) {
  42   key->clear();
  43   value->clear();
  44
  45   // Find the delimiter.
  46   size_t end_key_pos = line.find_first_of(key_value_delimiter);
  47   if (end_key_pos == std::string::npos) {
  48     DVLOG(1) << "cannot find delimiter in: " << line;
  49     return false;    // no delimiter
  50   }
  51   key->assign(line, 0, end_key_pos);
  52
  53   // Find the value string.
  54   std::string remains(line, end_key_pos, line.size() - end_key_pos);
  55   size_t begin_value_pos = remains.find_first_not_of(key_value_delimiter);
  56   if (begin_value_pos == std::string::npos) {
  57     DVLOG(1) << "cannot parse value from line: " << line;
  58     return false;   // no value
  59   }
  60   value->assign(remains, begin_value_pos, remains.size() - begin_value_pos);
  61   return true;
  62 }
  63
  64 template <typename STR>
  65 void SplitStringUsingSubstrT(const STR& str,
  66                                     const STR& s,
  67                                     std::vector<STR>* r) {
  68   r->clear();
  69   typename STR::size_type begin_index = 0;
  70   while (true) {
  71     const typename STR::size_type end_index = str.find(s, begin_index);
  72     if (end_index == STR::npos) {
  73       const STR term = str.substr(begin_index);
  74       STR tmp;
  75       TrimWhitespace(term, TRIM_ALL, &tmp);
  76       r->push_back(tmp);
  77       return;
  78     }
  79     const STR term = str.substr(begin_index, end_index - begin_index);
  80     STR tmp;
  81     TrimWhitespace(term, TRIM_ALL, &tmp);
  82     r->push_back(tmp);
  83     begin_index = end_index + s.size();
  84   }
  85 }
  86
  87 template<typename STR>
  88 void SplitStringAlongWhitespaceT(const STR& str, std::vector<STR>* result) {
  89   result->clear();
  90   const size_t length = str.length();
  91   if (!length)
  92     return;
  93
  94   bool last_was_ws = false;
  95   size_t last_non_ws_start = 0;
  96   for (size_t i = 0; i < length; ++i) {
  97     switch (str[i]) {
  98       // HTML 5 defines whitespace as: space, tab, LF, line tab, FF, or CR.
  99       case L' ':
 100       case L'\t':
 101       case L'\xA':
 102       case L'\xB':
 103       case L'\xC':
 104       case L'\xD':
 105         if (!last_was_ws) {
 106           if (i > 0) {
 107             result->push_back(
 108                 str.substr(last_non_ws_start, i - last_non_ws_start));
 109           }
 110           last_was_ws = true;
 111         }
 112         break;
 113
 114       default:  // Not a space character.
 115         if (last_was_ws) {
 116           last_was_ws = false;
 117           last_non_ws_start = i;
 118         }
 119         break;
 120     }
 121   }
 122   if (!last_was_ws) {
 123     result->push_back(
 124         str.substr(last_non_ws_start, length - last_non_ws_start));
 125   }
 126 }
 127
 128 }  // namespace
 129
 130 void SplitString(const string16& str,
 131                  char16 c,
 132                  std::vector<string16>* r) {
 133   DCHECK(CBU16_IS_SINGLE(c));
 134   SplitStringT(str, c, true, r);
 135 }
 136
 137 void SplitString(const std::string& str,
 138                  char c,
 139                  std::vector<std::string>* r) {
 140 #if CHAR_MIN < 0
 141   DCHECK(c >= 0);
 142 #endif
 143   DCHECK(c < 0x7F);
 144   SplitStringT(str, c, true, r);
 145 }
 146
 147 bool SplitStringIntoKeyValuePairs(const std::string& line,
 148                                   char key_value_delimiter,
 149                                   char key_value_pair_delimiter,
 150                                   StringPairs* key_value_pairs) {
 151   key_value_pairs->clear();
 152
 153   std::vector<std::string> pairs;
 154   SplitString(line, key_value_pair_delimiter, &pairs);
 155
 156   bool success = true;
 157   for (size_t i = 0; i < pairs.size(); ++i) {
 158     // Don't add empty pairs into the result.
 159     if (pairs[i].empty())
 160       continue;
 161
 162     std::string key;
 163     std::string value;
 164     if (!SplitStringIntoKeyValue(pairs[i], key_value_delimiter, &key, &value)) {
 165       // Don't return here, to allow for pairs without associated
 166       // value or key; just record that the split failed.
 167       success = false;
 168     }
 169     key_value_pairs->push_back(make_pair(key, value));
 170   }
 171   return success;
 172 }
 173
 174 void SplitStringUsingSubstr(const string16& str,
 175                             const string16& s,
 176                             std::vector<string16>* r) {
 177   SplitStringUsingSubstrT(str, s, r);
 178 }
 179
 180 void SplitStringUsingSubstr(const std::string& str,
 181                             const std::string& s,
 182                             std::vector<std::string>* r) {
 183   SplitStringUsingSubstrT(str, s, r);
 184 }
 185
 186 void SplitStringDontTrim(const string16& str,
 187                          char16 c,
 188                          std::vector<string16>* r) {
 189   DCHECK(CBU16_IS_SINGLE(c));
 190   SplitStringT(str, c, false, r);
 191 }
 192
 193 void SplitStringDontTrim(const std::string& str,
 194                          char c,
 195                          std::vector<std::string>* r) {
 196   DCHECK(IsStringUTF8(str));
 197 #if CHAR_MIN < 0
 198   DCHECK(c >= 0);
 199 #endif
 200   DCHECK(c < 0x7F);
 201   SplitStringT(str, c, false, r);
 202 }
 203
 204 void SplitStringAlongWhitespace(const string16& str,
 205                                 std::vector<string16>* result) {
 206   SplitStringAlongWhitespaceT(str, result);
 207 }
 208
 209 void SplitStringAlongWhitespace(const std::string& str,
 210                                 std::vector<std::string>* result) {
 211   SplitStringAlongWhitespaceT(str, result);
 212 }
 213
 214 }  // namespace base